[v2,00/11] fw_devlink improvements

This patch series improves fw_devlink in the following ways:

1. It no longer cares about a fwnode having a "compatible" property. It
   figures this our more dynamically. The only expectation is that
   fwnode that are converted to devices actually get probed by a driver
   for the dependencies to be enforced correctly.

2. Finer grained dependency tracking. fw_devlink will now create device
   links from the consumer to the actual resource's device (if it has one,
   Eg: gpio_device) instead of the parent supplier device. This improves
   things like async suspend/resume ordering, potentially remove the need
   for frameworks to create device links, more parallelized async probing,
   and better sync_state() tracking.

3. Handle hardware/software quirks where a child firmware node gets
   populated as a device before its parent firmware node AND actually
   supplies a non-optional resource to the parent firmware node's
   device.

4. Way more robust at cycle handling (see patch for the insane cases).

5. Stops depending on OF_POPULATED to figure out some corner cases.

6. Simplifies the work that needs to be done by the firmware specific
   code.

Sorry it took a while to roll in the fixes I gave in the v1 series
thread[1] into a v2 series.

Since I didn't make any additional changes on top of what I already gave
in the v1 thread and Dmitry is very eager to get this series going, I'm
sending it out without testing locally. I already tested these patches a
few months ago as part of the v1 series. So I don't expect any major
issues. I'll test them again on my end in the next few days and will
report here if I actually find anything wrong.

Tony, Naresh, Abel, Sudeep, Geert,

I got the following reviewed by's and tested by's a few months back, but
it's been 5 months since I sent out v1. So I wasn't sure if it was okay
to include them in the v2 commits. Let me know if you are okay with this
being included in the commits and/or if you want to test this series
again.

Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Abel Vesa <abel.vesa@linaro.org>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Dmitry, Maxim(s), Miquel, Luca, Doug, Colin, Martin, Jean-Philippe,

I've Cc-ed you because I had pointed you to v1 of this series + the
patches in that thread at one point or another as a fix to some issue
you were facing. It'd appreciate it if you can test this series and
report any issues, or things it fixed and give Tested-bys.

In addition, if you can also apply a revert of this series[2] and delete
driver_deferred_probe_check_state() from your tree and see if you hit
any issues and report them, that'd be great too! I'm pretty sure some of
you will hit issues with that. I want to fix those next and then
revert[2].

Thanks,
Saravana

[1] - https://lore.kernel.org/lkml/20220810060040.321697-1-saravanak@google.com/
[2] - https://lore.kernel.org/lkml/20220819221616.2107893-1-saravanak@google.com/
[3] - https://lore.kernel.org/lkml/CAGETcx-JUV1nj8wBJrTPfyvM7=Mre5j_vkVmZojeiumUGG6QZQ@mail.gmail.com/

v1 -> v2:
- Fixed Patch 1 to handle a corner case discussed in [3].
- New patch 10 to handle "fsl,imx8mq-gpc" being initialized by 2 drivers.
- New patch 11 to add fw_devlink support for SCMI devices.

Cc: Abel Vesa <abel.vesa@linaro.org>
Cc: Alexander Stein <alexander.stein@ew.tq-group.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: John Stultz <jstultz@google.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Maxim Kiselev <bigunclemax@gmail.com>
Cc: Maxim Kochetkov <fido_max@inbox.ru>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Luca Weiss <luca.weiss@fairphone.com>
Cc: Colin Foster <colin.foster@in-advantage.com>
Cc: Martin Kepplinger <martin.kepplinger@puri.sm>
Cc: Jean-Philippe Brucker <jpb@kernel.org>

Saravana Kannan (11):
  driver core: fw_devlink: Don't purge child fwnode's consumer links
  driver core: fw_devlink: Improve check for fwnode with no
    device/driver
  soc: renesas: Move away from using OF_POPULATED for fw_devlink
  gpiolib: Clear the gpio_device's fwnode initialized flag before adding
  driver core: fw_devlink: Add DL_FLAG_CYCLE support to device links
  driver core: fw_devlink: Allow marking a fwnode link as being part of
    a cycle
  driver core: fw_devlink: Consolidate device link flag computation
  driver core: fw_devlink: Make cycle detection more robust
  of: property: Simplify of_link_to_phandle()
  irqchip/irq-imx-gpcv2: Mark fwnode device as not initialized
  firmware: arm_scmi: Set fwnode for the scmi_device

 drivers/base/core.c             | 443 +++++++++++++++++++++-----------
 drivers/firmware/arm_scmi/bus.c |   2 +
 drivers/gpio/gpiolib.c          |   6 +
 drivers/irqchip/irq-imx-gpcv2.c |   1 +
 drivers/of/property.c           |  84 +-----
 drivers/soc/imx/gpcv2.c         |   1 +
 drivers/soc/renesas/rcar-sysc.c |   2 +-
 include/linux/device.h          |   1 +
 include/linux/fwnode.h          |  12 +-
 9 files changed, 332 insertions(+), 220 deletions(-)

On Fri, Jan 27, 2023 at 12:30 PM Colin Foster
<colin.foster@in-advantage.com> wrote:
>
> On Thu, Jan 26, 2023 at 04:11:27PM -0800, Saravana Kannan wrote:
> > Dmitry, Maxim(s), Miquel, Luca, Doug, Colin, Martin, Jean-Philippe,
> >
> > I've Cc-ed you because I had pointed you to v1 of this series + the
> > patches in that thread at one point or another as a fix to some issue
> > you were facing. It'd appreciate it if you can test this series and
> > report any issues, or things it fixed and give Tested-bys.
>
> I applied this on my working net-next/main development branch and can
> confirm I am able to successfully boot the Beaglebone Black.
>
> Tested-by: Colin Foster <colin.foster@in-advantage.com>

Thanks!

-Saravana

On Fri, Jan 27, 2023 at 12:11 AM Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
>
> Hi Saravana,
>
> On Fri, Jan 27, 2023 at 1:11 AM Saravana Kannan <saravanak@google.com> wrote:
> > The OF_POPULATED flag was set to let fw_devlink know that the device
> > tree node will not have a struct device created for it. This information
> > is used by fw_devlink to avoid deferring the probe of consumers of this
> > device tree node.
> >
> > Let's use fwnode_dev_initialized() instead because it achieves the same
> > effect without using OF specific flags. This allows more generic code to
> > be written in driver core.
> >
> > Signed-off-by: Saravana Kannan <saravanak@google.com>
>
> Thanks for your patch!
>
> > --- a/drivers/soc/renesas/rcar-sysc.c
> > +++ b/drivers/soc/renesas/rcar-sysc.c
> > @@ -437,7 +437,7 @@ static int __init rcar_sysc_pd_init(void)
> >
> >         error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
> >         if (!error)
> > -               of_node_set_flag(np, OF_POPULATED);
> > +               fwnode_dev_initialized(&np->fwnode, true);
>
> As drivers/soc/renesas/rmobile-sysc.c is already using this method,
> it should work fine.
>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> i.e. will queue in renesas-devel for v6.4.

Thanks! Does that mean I should drop this from this series? If two
maintainers pick the same patch up, will it cause problems? I'm
eventually expecting this series to be picked up by Greg into
driver-core-next.

-Saravana

>
> >
> >  out_put:
> >         of_node_put(np);
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds

Hi Saravana,

On Sat, Jan 28, 2023 at 8:19 AM Saravana Kannan <saravanak@google.com> wrote:
> On Fri, Jan 27, 2023 at 12:11 AM Geert Uytterhoeven
> <geert@linux-m68k.org> wrote:
> > On Fri, Jan 27, 2023 at 1:11 AM Saravana Kannan <saravanak@google.com> wrote:
> > > The OF_POPULATED flag was set to let fw_devlink know that the device
> > > tree node will not have a struct device created for it. This information
> > > is used by fw_devlink to avoid deferring the probe of consumers of this
> > > device tree node.
> > >
> > > Let's use fwnode_dev_initialized() instead because it achieves the same
> > > effect without using OF specific flags. This allows more generic code to
> > > be written in driver core.
> > >
> > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> >
> > Thanks for your patch!
> >
> > > --- a/drivers/soc/renesas/rcar-sysc.c
> > > +++ b/drivers/soc/renesas/rcar-sysc.c
> > > @@ -437,7 +437,7 @@ static int __init rcar_sysc_pd_init(void)
> > >
> > >         error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
> > >         if (!error)
> > > -               of_node_set_flag(np, OF_POPULATED);
> > > +               fwnode_dev_initialized(&np->fwnode, true);
> >
> > As drivers/soc/renesas/rmobile-sysc.c is already using this method,
> > it should work fine.
> >
> > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > i.e. will queue in renesas-devel for v6.4.
>
> Thanks! Does that mean I should drop this from this series? If two
> maintainers pick the same patch up, will it cause problems? I'm
> eventually expecting this series to be picked up by Greg into
> driver-core-next.

Indeed. Patches for drivers/soc/renesas/ are supposed to go upstream
through the renesas-devel and soc trees. This patch has no dependencies
on anything else in the series (or vice versa), so there is no reason
to deviate from that, and possibly cause conflicts later.

BTW, I will convert to of_node_to_fwnode() while applying.

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Build test pass on arm, arm64, i386, mips, parisc, powerpc, riscv, s390, sh,
sparc and x86_64.

Boot and LTP smoke pass on qemu-arm64, qemu-armv7, qemu-i386 and qemu-x86_64.
Boot failed on FVP.

Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>

Please refer following link for details of testing.
FVP boot log failed.
https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/lore_kernel_org_linux-devicetree_20230127001141_407071-1-saravanak_google_com/testrun/14389034/suite/boot/test/gcc-12-lkftconfig-64k_page_size/details/


[    2.613437] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
[    2.613628] Mem abort info:
[    2.613756]   ESR = 0x0000000096000005
[    2.613904]   EC = 0x25: DABT (current EL), IL = 32 bits
[    2.614071]   SET = 0, FnV = 0
[    2.614215]   EA = 0, S1PTW = 0
[    2.614358]   FSC = 0x05: level 1 translation fault
[    2.614517] Data abort info:
[    2.614647]   ISV = 0, ISS = 0x00000005
[    2.614792]   CM = 0, WnR = 0
[    2.614934] [0000000000000010] user address but active_mm is swapper
[    2.615105] Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
[    2.615219] Modules linked in:
[    2.615310] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.2.0-rc5 #1
[    2.615445] Hardware name: FVP Base RevC (DT)
[    2.615533] pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[    2.615685] pc : gpiochip_setup_dev (include/linux/err.h:41 include/linux/fwnode.h:201 drivers/gpio/gpiolib.c:586) 
[    2.615816] lr : gpiochip_add_data_with_key (drivers/gpio/gpiolib.c:871) 
[    2.615970] sp : ffff8000081af5e0
[    2.616051] x29: ffff8000081af5e0 x28: 0000000000000000 x27: ffff0008027cb5a0
[    2.616261] x26: 0000000000000000 x25: ffffd7c5d6745910 x24: ffff0008027f4800
[    2.616472] x23: 0000000000000000 x22: ffffd7c5d62b99a8 x21: 0000000000000202
[    2.616679] x20: 0000000000000000 x19: ffff0008027f4800 x18: ffffffffffffffff
[    2.616890] x17: ffffd7c5d6467928 x16: 0000000013e3690a x15: ffff8000081af3b0
[    2.617102] x14: ffff00080275cd8a x13: ffff00080275cd88 x12: 0000000000000001
[    2.617312] x11: 62726568746f6d3a x10: 0000000000000000 x9 : ffffd7c5d3b3ebe0
[    2.617522] x8 : ffff8000081af548 x7 : 0000000000000000 x6 : 0000000000000001
[    2.617727] x5 : 0000000000000000 x4 : ffff000800640000 x3 : ffffd7c5d62b99c8
[    2.617933] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
[    2.618138] Call trace:
[    2.618204] gpiochip_setup_dev (include/linux/err.h:41 include/linux/fwnode.h:201 drivers/gpio/gpiolib.c:586) 
[    2.618337] gpiochip_add_data_with_key (drivers/gpio/gpiolib.c:871) 
[    2.618493] devm_gpiochip_add_data_with_key (drivers/gpio/gpiolib-devres.c:478) 
[    2.618654] bgpio_pdev_probe (drivers/gpio/gpio-mmio.c:793) 
[    2.618785] platform_probe (drivers/base/platform.c:1401) 
[    2.618928] really_probe (drivers/base/dd.c:560 drivers/base/dd.c:639) 
[    2.619056] __driver_probe_device (drivers/base/dd.c:778) 
[    2.619193] driver_probe_device (drivers/base/dd.c:808) 
[    2.619329] __device_attach_driver (drivers/base/dd.c:937) 
[    2.619464] bus_for_each_drv (drivers/base/bus.c:427) 
[    2.619590] __device_attach (drivers/base/dd.c:1010) 
[    2.619722] device_initial_probe (drivers/base/dd.c:1058) 
[    2.619861] bus_probe_device (drivers/base/bus.c:489) 
[    2.619988] device_add (drivers/base/core.c:3637) 
[    2.620102] platform_device_add (drivers/base/platform.c:717) 
[    2.620251] mfd_add_device (drivers/mfd/mfd-core.c:297) 
[    2.620397] devm_mfd_add_devices (drivers/mfd/mfd-core.c:351 drivers/mfd/mfd-core.c:449) 
[    2.620548] vexpress_sysreg_probe (drivers/mfd/vexpress-sysreg.c:115) 
[    2.620672] platform_probe (drivers/base/platform.c:1401) 
[    2.620814] really_probe (drivers/base/dd.c:560 drivers/base/dd.c:639) 
[    2.620940] __driver_probe_device (drivers/base/dd.c:778) 
[    2.621080] driver_probe_device (drivers/base/dd.c:808) 
[    2.621216] __driver_attach (drivers/base/dd.c:1195) 
[    2.621344] bus_for_each_dev (drivers/base/bus.c:301) 
[    2.621467] driver_attach (drivers/base/dd.c:1212) 
[    2.621596] bus_add_driver (drivers/base/bus.c:618) 
[    2.621720] driver_register (drivers/base/driver.c:246) 
[    2.621859] __platform_driver_register (drivers/base/platform.c:868) 
[    2.622012] vexpress_sysreg_driver_init (drivers/mfd/vexpress-sysreg.c:134) 
[    2.622145] do_one_initcall (init/main.c:1306) 
[    2.622269] kernel_init_freeable (init/main.c:1378 init/main.c:1395 init/main.c:1414 init/main.c:1634) 
[    2.622394] kernel_init (init/main.c:1526) 
[    2.622531] ret_from_fork (arch/arm64/kernel/entry.S:864) 
[ 2.622692] Code: 910003fd a90153f3 aa0003f3 f9414c00 (f9400801)
All code
========
   0:*	fd                   	std    		<-- trapping instruction
   1:	03 00                	add    (%rax),%eax
   3:	91                   	xchg   %eax,%ecx
   4:	f3 53                	repz push %rbx
   6:	01 a9 f3 03 00 aa    	add    %ebp,-0x55fffc0d(%rcx)
   c:	00 4c 41 f9          	add    %cl,-0x7(%rcx,%rax,2)
  10:	01 08                	add    %ecx,(%rax)
  12:	40 f9                	rex stc 

Code starting with the faulting instruction
===========================================
   0:	01 08                	add    %ecx,(%rax)
   2:	40 f9                	rex stc 
[    2.622807] ---[ end trace 0000000000000000 ]---
[    2.623043] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
[    2.623157] SMP: stopping secondary CPUs
[    2.623303] Kernel Offset: 0x57c5cb400000 from 0xffff800008000000
[    2.623413] PHYS_OFFSET: 0x80000000
[    2.623492] CPU features: 0x00000,001439ff,cd3e772f
[    2.623591] Memory Limit: none
[    2.623679] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]---


ref:
 - https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/lore_kernel_org_linux-devicetree_20230127001141_407071-1-saravanak_google_com/?results_layout=table&failures_only=false#!?details=#test-results



--
Linaro LKFT
https://lkft.linaro.org

Hi Maxim & Maxim,

saravanak@google.com wrote on Thu, 26 Jan 2023 16:11:27 -0800:

> This patch series improves fw_devlink in the following ways:
> 
> 1. It no longer cares about a fwnode having a "compatible" property. It
>    figures this our more dynamically. The only expectation is that
>    fwnode that are converted to devices actually get probed by a driver
>    for the dependencies to be enforced correctly.
> 
> 2. Finer grained dependency tracking. fw_devlink will now create device
>    links from the consumer to the actual resource's device (if it has one,
>    Eg: gpio_device) instead of the parent supplier device. This improves
>    things like async suspend/resume ordering, potentially remove the need
>    for frameworks to create device links, more parallelized async probing,
>    and better sync_state() tracking.
> 
> 3. Handle hardware/software quirks where a child firmware node gets
>    populated as a device before its parent firmware node AND actually
>    supplies a non-optional resource to the parent firmware node's
>    device.
> 
> 4. Way more robust at cycle handling (see patch for the insane cases).
> 
> 5. Stops depending on OF_POPULATED to figure out some corner cases.
> 
> 6. Simplifies the work that needs to be done by the firmware specific
>    code.
> 
> Sorry it took a while to roll in the fixes I gave in the v1 series
> thread[1] into a v2 series.
> 
> Since I didn't make any additional changes on top of what I already gave
> in the v1 thread and Dmitry is very eager to get this series going, I'm
> sending it out without testing locally. I already tested these patches a
> few months ago as part of the v1 series. So I don't expect any major
> issues. I'll test them again on my end in the next few days and will
> report here if I actually find anything wrong.
> 
> Tony, Naresh, Abel, Sudeep, Geert,
> 
> I got the following reviewed by's and tested by's a few months back, but
> it's been 5 months since I sent out v1. So I wasn't sure if it was okay
> to include them in the v2 commits. Let me know if you are okay with this
> being included in the commits and/or if you want to test this series
> again.
> 
> Reviewed-by: Tony Lindgren <tony@atomide.com>
> Tested-by: Tony Lindgren <tony@atomide.com>
> Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Tested-by: Abel Vesa <abel.vesa@linaro.org>
> Tested-by: Sudeep Holla <sudeep.holla@arm.com>
> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
> 
> Dmitry, Maxim(s), Miquel, Luca, Doug, Colin, Martin, Jean-Philippe,
> 
> I've Cc-ed you because I had pointed you to v1 of this series + the
> patches in that thread at one point or another as a fix to some issue
> you were facing. It'd appreciate it if you can test this series and
> report any issues, or things it fixed and give Tested-bys.

Maxim & Maxim I would really appreciate if you could validate that the
original issue you had is solved with this version? I don't have any
hardware suffering from this issue.

> In addition, if you can also apply a revert of this series[2] and delete
> driver_deferred_probe_check_state() from your tree and see if you hit
> any issues and report them, that'd be great too! I'm pretty sure some of
> you will hit issues with that. I want to fix those next and then
> revert[2].
> 
> Thanks,
> Saravana
> 
> [1] - https://lore.kernel.org/lkml/20220810060040.321697-1-saravanak@google.com/
> [2] - https://lore.kernel.org/lkml/20220819221616.2107893-1-saravanak@google.com/
> [3] - https://lore.kernel.org/lkml/CAGETcx-JUV1nj8wBJrTPfyvM7=Mre5j_vkVmZojeiumUGG6QZQ@mail.gmail.com/
> 
> v1 -> v2:
> - Fixed Patch 1 to handle a corner case discussed in [3].
> - New patch 10 to handle "fsl,imx8mq-gpc" being initialized by 2 drivers.
> - New patch 11 to add fw_devlink support for SCMI devices.
> 
> Cc: Abel Vesa <abel.vesa@linaro.org>
> Cc: Alexander Stein <alexander.stein@ew.tq-group.com>
> Cc: Tony Lindgren <tony@atomide.com>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: John Stultz <jstultz@google.com>
> Cc: Doug Anderson <dianders@chromium.org>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Cc: Maxim Kiselev <bigunclemax@gmail.com>
> Cc: Maxim Kochetkov <fido_max@inbox.ru>
> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: Luca Weiss <luca.weiss@fairphone.com>
> Cc: Colin Foster <colin.foster@in-advantage.com>
> Cc: Martin Kepplinger <martin.kepplinger@puri.sm>
> Cc: Jean-Philippe Brucker <jpb@kernel.org>
> 
> Saravana Kannan (11):
>   driver core: fw_devlink: Don't purge child fwnode's consumer links
>   driver core: fw_devlink: Improve check for fwnode with no
>     device/driver
>   soc: renesas: Move away from using OF_POPULATED for fw_devlink
>   gpiolib: Clear the gpio_device's fwnode initialized flag before adding
>   driver core: fw_devlink: Add DL_FLAG_CYCLE support to device links
>   driver core: fw_devlink: Allow marking a fwnode link as being part of
>     a cycle
>   driver core: fw_devlink: Consolidate device link flag computation
>   driver core: fw_devlink: Make cycle detection more robust
>   of: property: Simplify of_link_to_phandle()
>   irqchip/irq-imx-gpcv2: Mark fwnode device as not initialized
>   firmware: arm_scmi: Set fwnode for the scmi_device
> 
>  drivers/base/core.c             | 443 +++++++++++++++++++++-----------
>  drivers/firmware/arm_scmi/bus.c |   2 +
>  drivers/gpio/gpiolib.c          |   6 +
>  drivers/irqchip/irq-imx-gpcv2.c |   1 +
>  drivers/of/property.c           |  84 +-----
>  drivers/soc/imx/gpcv2.c         |   1 +
>  drivers/soc/renesas/rcar-sysc.c |   2 +-
>  include/linux/device.h          |   1 +
>  include/linux/fwnode.h          |  12 +-
>  9 files changed, 332 insertions(+), 220 deletions(-)
> 


Thanks,
Miquèl

On Mon, 30 Jan 2023 08:55:42 +0000,
Naresh Kamboju <naresh.kamboju@linaro.org> wrote:
> 
> Build test pass on arm, arm64, i386, mips, parisc, powerpc, riscv, s390, sh,
> sparc and x86_64.
> 
> Boot and LTP smoke pass on qemu-arm64, qemu-armv7, qemu-i386 and qemu-x86_64.
> Boot failed on FVP.
> 
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> 
> Please refer following link for details of testing.
> FVP boot log failed.
> https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/lore_kernel_org_linux-devicetree_20230127001141_407071-1-saravanak_google_com/testrun/14389034/suite/boot/test/gcc-12-lkftconfig-64k_page_size/details/
> 
> 
> [    2.613437] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
> [    2.613628] Mem abort info:
> [    2.613756]   ESR = 0x0000000096000005
> [    2.613904]   EC = 0x25: DABT (current EL), IL = 32 bits
> [    2.614071]   SET = 0, FnV = 0
> [    2.614215]   EA = 0, S1PTW = 0
> [    2.614358]   FSC = 0x05: level 1 translation fault
> [    2.614517] Data abort info:
> [    2.614647]   ISV = 0, ISS = 0x00000005
> [    2.614792]   CM = 0, WnR = 0
> [    2.614934] [0000000000000010] user address but active_mm is swapper
> [    2.615105] Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
> [    2.615219] Modules linked in:
> [    2.615310] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.2.0-rc5 #1
> [    2.615445] Hardware name: FVP Base RevC (DT)
> [    2.615533] pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
> [    2.615685] pc : gpiochip_setup_dev (include/linux/err.h:41 include/linux/fwnode.h:201 drivers/gpio/gpiolib.c:586) 
> [    2.615816] lr : gpiochip_add_data_with_key (drivers/gpio/gpiolib.c:871) 
> [    2.615970] sp : ffff8000081af5e0
> [    2.616051] x29: ffff8000081af5e0 x28: 0000000000000000 x27: ffff0008027cb5a0
> [    2.616261] x26: 0000000000000000 x25: ffffd7c5d6745910 x24: ffff0008027f4800
> [    2.616472] x23: 0000000000000000 x22: ffffd7c5d62b99a8 x21: 0000000000000202
> [    2.616679] x20: 0000000000000000 x19: ffff0008027f4800 x18: ffffffffffffffff
> [    2.616890] x17: ffffd7c5d6467928 x16: 0000000013e3690a x15: ffff8000081af3b0
> [    2.617102] x14: ffff00080275cd8a x13: ffff00080275cd88 x12: 0000000000000001
> [    2.617312] x11: 62726568746f6d3a x10: 0000000000000000 x9 : ffffd7c5d3b3ebe0
> [    2.617522] x8 : ffff8000081af548 x7 : 0000000000000000 x6 : 0000000000000001
> [    2.617727] x5 : 0000000000000000 x4 : ffff000800640000 x3 : ffffd7c5d62b99c8
> [    2.617933] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
> [    2.618138] Call trace:
> [    2.618204] gpiochip_setup_dev (include/linux/err.h:41 include/linux/fwnode.h:201 drivers/gpio/gpiolib.c:586) 
> [    2.618337] gpiochip_add_data_with_key (drivers/gpio/gpiolib.c:871) 
> [    2.618493] devm_gpiochip_add_data_with_key (drivers/gpio/gpiolib-devres.c:478) 
> [    2.618654] bgpio_pdev_probe (drivers/gpio/gpio-mmio.c:793) 
> [    2.618785] platform_probe (drivers/base/platform.c:1401) 
> [    2.618928] really_probe (drivers/base/dd.c:560 drivers/base/dd.c:639) 
> [    2.619056] __driver_probe_device (drivers/base/dd.c:778) 
> [    2.619193] driver_probe_device (drivers/base/dd.c:808) 
> [    2.619329] __device_attach_driver (drivers/base/dd.c:937) 
> [    2.619464] bus_for_each_drv (drivers/base/bus.c:427) 
> [    2.619590] __device_attach (drivers/base/dd.c:1010) 
> [    2.619722] device_initial_probe (drivers/base/dd.c:1058) 
> [    2.619861] bus_probe_device (drivers/base/bus.c:489) 
> [    2.619988] device_add (drivers/base/core.c:3637) 
> [    2.620102] platform_device_add (drivers/base/platform.c:717) 
> [    2.620251] mfd_add_device (drivers/mfd/mfd-core.c:297) 
> [    2.620397] devm_mfd_add_devices (drivers/mfd/mfd-core.c:351 drivers/mfd/mfd-core.c:449) 
> [    2.620548] vexpress_sysreg_probe (drivers/mfd/vexpress-sysreg.c:115) 
> [    2.620672] platform_probe (drivers/base/platform.c:1401) 
> [    2.620814] really_probe (drivers/base/dd.c:560 drivers/base/dd.c:639) 
> [    2.620940] __driver_probe_device (drivers/base/dd.c:778) 
> [    2.621080] driver_probe_device (drivers/base/dd.c:808) 
> [    2.621216] __driver_attach (drivers/base/dd.c:1195) 
> [    2.621344] bus_for_each_dev (drivers/base/bus.c:301) 
> [    2.621467] driver_attach (drivers/base/dd.c:1212) 
> [    2.621596] bus_add_driver (drivers/base/bus.c:618) 
> [    2.621720] driver_register (drivers/base/driver.c:246) 
> [    2.621859] __platform_driver_register (drivers/base/platform.c:868) 
> [    2.622012] vexpress_sysreg_driver_init (drivers/mfd/vexpress-sysreg.c:134) 
> [    2.622145] do_one_initcall (init/main.c:1306) 
> [    2.622269] kernel_init_freeable (init/main.c:1378 init/main.c:1395 init/main.c:1414 init/main.c:1634) 
> [    2.622394] kernel_init (init/main.c:1526) 
> [    2.622531] ret_from_fork (arch/arm64/kernel/entry.S:864) 
> [ 2.622692] Code: 910003fd a90153f3 aa0003f3 f9414c00 (f9400801)
> All code
> ========
>    0:*	fd                   	std    		<-- trapping instruction
>    1:	03 00                	add    (%rax),%eax
>    3:	91                   	xchg   %eax,%ecx
>    4:	f3 53                	repz push %rbx
>    6:	01 a9 f3 03 00 aa    	add    %ebp,-0x55fffc0d(%rcx)
>    c:	00 4c 41 f9          	add    %cl,-0x7(%rcx,%rax,2)
>   10:	01 08                	add    %ecx,(%rax)
>   12:	40 f9                	rex stc

Could you please fix your scripts so that they report something that
matches the tested architecture? I like x86 asm as much as the next
guy, but this is an arm64 crash... :-/

Thanks,

	M.

On Fri, Jan 27, 2023 at 11:33:28PM -0800, Saravana Kannan wrote:
> On Fri, Jan 27, 2023 at 1:22 AM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Thu, Jan 26, 2023 at 04:11:28PM -0800, Saravana Kannan wrote:

...

> > >  static unsigned int defer_sync_state_count = 1;
> > >  static DEFINE_MUTEX(fwnode_link_lock);
> > >  static bool fw_devlink_is_permissive(void);
> > > +static void __fw_devlink_link_to_consumers(struct device *dev);
> > >  static bool fw_devlink_drv_reg_done;
> > >  static bool fw_devlink_best_effort;
> >
> > I'm wondering if may avoid adding more forward declarations...
> >
> > Perhaps it's a sign that devlink code should be split to its own
> > module?
> 
> I've thought about that before, but I'm not there yet. Maybe once my
> remaining refactors and TODOs are done, it'd be a good time to revisit
> this question.
> 
> But I don't think it should be done for the reason of forward
> declaration as we'd just end up moving these into base.h and we can do
> that even today.

What I meant is that the stacking up forward declarations is a good sign that
something has to be done sooner than later.

...

> > > -int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
> > > +static int __fwnode_link_add(struct fwnode_handle *con,
> > > +                          struct fwnode_handle *sup)
> >
> > I believe we tolerate a bit longer lines, so you may still have it on a single
> > line.
> 
> That'd make it >80 cols. I'm going to leave it as is.

Is it a problem?

...

> > >       if (dev->fwnode && dev->fwnode->dev == dev) {
> >
> > You may have above something like
> >
> >         fwnode = dev_fwnode(dev);
> 
> I'll leave it as-is for now. I see dev->fwnode vs dev_fwnode() don't
> always give the same results. I need to re-examine other places I use
> dev->fwnode in fw_devlink code before I start using that function. But
> in general it seems like a good idea. I'll add this to my TODOs.

Please do, the rationale is to actually move the fwnode to the proper layer,
now we have the single linked list defined in struct fwnode_handle and
dereferencing fwnode from struct device without helper adds a lot of
headache in the future. So, I really would like to see that we stopped doing
that.

> >         if (fwnode && fwnode->dev == dev) {
> >
> > >               struct fwnode_handle *child;
> > >               fwnode_links_purge_suppliers(dev->fwnode);
> > > +             mutex_lock(&fwnode_link_lock);
> > >               fwnode_for_each_available_child_node(dev->fwnode, child)
> > > -                     fw_devlink_purge_absent_suppliers(child);
> > > +                     __fw_devlink_pickup_dangling_consumers(child,
> > > +                                                            dev->fwnode);
> >
> >                         __fw_devlink_pickup_dangling_consumers(child, fwnode);
> 
> I like the dev->fwnode->dev == dev check. It makes it super clear that
> I'm checking "The device's fwnode points back to the device". If I
> just use fwnode->dev == dev, then one will have to go back and read
> what fwnode is set to, etc. Also, when reading all these function
> calls it's easier to see that I'm working on the dev's fwnode (where
> dev is the device that was just bound to a driver) instead of some
> other fwnode.
> 
> So I find it more readable as is and the compiler would optimize it
> anyway. If you feel strongly about this, I can change to use fwnode
> instead of dev->fwnode.

Please, read above.

On Fri, Jan 27, 2023 at 11:34:11PM -0800, Saravana Kannan wrote:
> On Fri, Jan 27, 2023 at 1:30 AM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Thu, Jan 26, 2023 at 04:11:32PM -0800, Saravana Kannan wrote:

...

> > >                              DL_FLAG_AUTOREMOVE_SUPPLIER | \
> > >                              DL_FLAG_AUTOPROBE_CONSUMER  | \
> > >                              DL_FLAG_SYNC_STATE_ONLY | \
> > > -                            DL_FLAG_INFERRED)
> > > +                            DL_FLAG_INFERRED | \
> > > +                            DL_FLAG_CYCLE)
> >
> > You can make less churn by squeezing the new one above the last one.
> 
> I feel like this part is getting bike shedded. I'm going to leave it
> as is. It's done in the order it's defined in the header and keeping
> it that way makes it way more easier to read than worry about a single
> line churn.

Not at all. What you are showing here is the additional churn for the sake of
the churn. With a no-cost trick you may avoid that.

Also, it will compress better the Git index and save some mW here and there
and in the size of the world and amount of Git copies of the Linux kernel
this may save the planet (I'm serious, no jokes).

Hi Saravana & Miquel.

Sorry for the long response. I finally got access to my test device
and tried this patch series.

And unfortunately it didn't solve my issue. I'm still getting a
hanging f1070000.ethernet dependency
from the nvmem-cell mac@6 subnode.

Here are related parts of my kernel log and device tree:


    [    2.713302] device: 'mtd-0': device_add
    [    2.719528] device: 'spi0': device_add
    [    2.724180] device: 'spi0.0': device_add
    [    2.728957] spi-nor spi0.0: mx66l51235f (65536 Kbytes)
    [    2.735338] 7 fixed-partitions partitions found on MTD device spi0.0
    [    2.741978] device:
'f1010600.spi:m25p80@0:partitions:partition@1': device_add
    [    2.749636] Creating 7 MTD partitions on "spi0.0":
    [    2.754564] 0x000000000000-0x000000080000 : "SPI.U_BOOT"
    [    2.759981] device: 'mtd0': device_add
    [    2.764323] device: 'mtd0': device_add
    [    2.768280] device: 'mtd0ro': device_add
    [    2.772624] 0x0000000a0000-0x0000000c0000 : "SPI.INV_INFO"
    [    2.778218] device: 'mtd1': device_add
    [    2.782549] device: 'mtd1': device_add
    [    2.786582] device: 'mtd1ro': device_add
    ...
    [    5.426625] mvneta_bm f10c0000.bm: Buffer Manager for network
controller enabled
    [    5.492867] platform f1070000.ethernet: error -EPROBE_DEFER:
wait for supplier mac@6
    [    5.528636] device: 'Fixed MDIO bus.0': device_add
    [    5.533726] device: 'fixed-0': device_add
    [    5.547564] device: 'f1072004.mdio-eth-mii': device_add
    [    5.616368] device: 'f1072004.mdio-eth-mii:00': device_add
    [    5.645127] device: 'f1072004.mdio-eth-mii:1e': device_add
    [    5.651530] devices_kset: Moving f1070000.ethernet to end of list
    [    5.657948] platform f1070000.ethernet: error -EPROBE_DEFER:
wait for supplier mac@6

    spi@10600 {
        m25p80@0 {
            compatible = "mx66l51235l";

            partitions {
                compatible = "fixed-partitions";

                partition@0 {
                    label = "SPI.U_BOOT";
                };
                partition@1 {
                    compatible = "nvmem-cells";
                    label = "SPI.INV_INFO";
                    macaddr: mac@6 {
                        reg = <0x6 0x6>;
                    };
                };
                ...
            };
        };
    };

    enet1: ethernet@70000 {
        nvmem-cells = <&macaddr>;
        nvmem-cell-names = "mac-address";
        phy-mode = "rgmii";
        phy = <&phy0>;
    };


Maybe I should provide some additional debug info?

пн, 30 янв. 2023 г. в 13:48, Miquel Raynal <miquel.raynal@bootlin.com>:
>
> Hi Maxim & Maxim,
>
> saravanak@google.com wrote on Thu, 26 Jan 2023 16:11:27 -0800:
>
> > This patch series improves fw_devlink in the following ways:
> >
> > 1. It no longer cares about a fwnode having a "compatible" property. It
> >    figures this our more dynamically. The only expectation is that
> >    fwnode that are converted to devices actually get probed by a driver
> >    for the dependencies to be enforced correctly.
> >
> > 2. Finer grained dependency tracking. fw_devlink will now create device
> >    links from the consumer to the actual resource's device (if it has one,
> >    Eg: gpio_device) instead of the parent supplier device. This improves
> >    things like async suspend/resume ordering, potentially remove the need
> >    for frameworks to create device links, more parallelized async probing,
> >    and better sync_state() tracking.
> >
> > 3. Handle hardware/software quirks where a child firmware node gets
> >    populated as a device before its parent firmware node AND actually
> >    supplies a non-optional resource to the parent firmware node's
> >    device.
> >
> > 4. Way more robust at cycle handling (see patch for the insane cases).
> >
> > 5. Stops depending on OF_POPULATED to figure out some corner cases.
> >
> > 6. Simplifies the work that needs to be done by the firmware specific
> >    code.
> >
> > Sorry it took a while to roll in the fixes I gave in the v1 series
> > thread[1] into a v2 series.
> >
> > Since I didn't make any additional changes on top of what I already gave
> > in the v1 thread and Dmitry is very eager to get this series going, I'm
> > sending it out without testing locally. I already tested these patches a
> > few months ago as part of the v1 series. So I don't expect any major
> > issues. I'll test them again on my end in the next few days and will
> > report here if I actually find anything wrong.
> >
> > Tony, Naresh, Abel, Sudeep, Geert,
> >
> > I got the following reviewed by's and tested by's a few months back, but
> > it's been 5 months since I sent out v1. So I wasn't sure if it was okay
> > to include them in the v2 commits. Let me know if you are okay with this
> > being included in the commits and/or if you want to test this series
> > again.
> >
> > Reviewed-by: Tony Lindgren <tony@atomide.com>
> > Tested-by: Tony Lindgren <tony@atomide.com>
> > Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
> > Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> > Tested-by: Abel Vesa <abel.vesa@linaro.org>
> > Tested-by: Sudeep Holla <sudeep.holla@arm.com>
> > Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
> >
> > Dmitry, Maxim(s), Miquel, Luca, Doug, Colin, Martin, Jean-Philippe,
> >
> > I've Cc-ed you because I had pointed you to v1 of this series + the
> > patches in that thread at one point or another as a fix to some issue
> > you were facing. It'd appreciate it if you can test this series and
> > report any issues, or things it fixed and give Tested-bys.
>
> Maxim & Maxim I would really appreciate if you could validate that the
> original issue you had is solved with this version? I don't have any
> hardware suffering from this issue.
>
> > In addition, if you can also apply a revert of this series[2] and delete
> > driver_deferred_probe_check_state() from your tree and see if you hit
> > any issues and report them, that'd be great too! I'm pretty sure some of
> > you will hit issues with that. I want to fix those next and then
> > revert[2].
> >
> > Thanks,
> > Saravana
> >
> > [1] - https://lore.kernel.org/lkml/20220810060040.321697-1-saravanak@google.com/
> > [2] - https://lore.kernel.org/lkml/20220819221616.2107893-1-saravanak@google.com/
> > [3] - https://lore.kernel.org/lkml/CAGETcx-JUV1nj8wBJrTPfyvM7=Mre5j_vkVmZojeiumUGG6QZQ@mail.gmail.com/
> >
> > v1 -> v2:
> > - Fixed Patch 1 to handle a corner case discussed in [3].
> > - New patch 10 to handle "fsl,imx8mq-gpc" being initialized by 2 drivers.
> > - New patch 11 to add fw_devlink support for SCMI devices.
> >
> > Cc: Abel Vesa <abel.vesa@linaro.org>
> > Cc: Alexander Stein <alexander.stein@ew.tq-group.com>
> > Cc: Tony Lindgren <tony@atomide.com>
> > Cc: Sudeep Holla <sudeep.holla@arm.com>
> > Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> > Cc: John Stultz <jstultz@google.com>
> > Cc: Doug Anderson <dianders@chromium.org>
> > Cc: Guenter Roeck <linux@roeck-us.net>
> > Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > Cc: Maxim Kiselev <bigunclemax@gmail.com>
> > Cc: Maxim Kochetkov <fido_max@inbox.ru>
> > Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> > Cc: Luca Weiss <luca.weiss@fairphone.com>
> > Cc: Colin Foster <colin.foster@in-advantage.com>
> > Cc: Martin Kepplinger <martin.kepplinger@puri.sm>
> > Cc: Jean-Philippe Brucker <jpb@kernel.org>
> >
> > Saravana Kannan (11):
> >   driver core: fw_devlink: Don't purge child fwnode's consumer links
> >   driver core: fw_devlink: Improve check for fwnode with no
> >     device/driver
> >   soc: renesas: Move away from using OF_POPULATED for fw_devlink
> >   gpiolib: Clear the gpio_device's fwnode initialized flag before adding
> >   driver core: fw_devlink: Add DL_FLAG_CYCLE support to device links
> >   driver core: fw_devlink: Allow marking a fwnode link as being part of
> >     a cycle
> >   driver core: fw_devlink: Consolidate device link flag computation
> >   driver core: fw_devlink: Make cycle detection more robust
> >   of: property: Simplify of_link_to_phandle()
> >   irqchip/irq-imx-gpcv2: Mark fwnode device as not initialized
> >   firmware: arm_scmi: Set fwnode for the scmi_device
> >
> >  drivers/base/core.c             | 443 +++++++++++++++++++++-----------
> >  drivers/firmware/arm_scmi/bus.c |   2 +
> >  drivers/gpio/gpiolib.c          |   6 +
> >  drivers/irqchip/irq-imx-gpcv2.c |   1 +
> >  drivers/of/property.c           |  84 +-----
> >  drivers/soc/imx/gpcv2.c         |   1 +
> >  drivers/soc/renesas/rcar-sysc.c |   2 +-
> >  include/linux/device.h          |   1 +
> >  include/linux/fwnode.h          |  12 +-
> >  9 files changed, 332 insertions(+), 220 deletions(-)
> >
>
>
> Thanks,
> Miquèl

Hi Saravana,

On Thu, Jan 26, 2023 at 04:11:36PM -0800, Saravana Kannan wrote:
> The driver core now:
> - Has the parent device of a supplier pick up the consumers if the
>   supplier never has a device created for it.
> - Ignores a supplier if the supplier has no parent device and will never
>   be probed by a driver
> 
> And already prevents creating a device link with the consumer as a
> supplier of a parent.
> 
> So, we no longer need to find the "compatible" node of the supplier or
> do any other checks in of_link_to_phandle(). We simply need to make sure
> that the supplier is available in DT.
> 
> Signed-off-by: Saravana Kannan <saravanak@google.com>
> ---
>  drivers/of/property.c | 84 +++++++------------------------------------
>  1 file changed, 13 insertions(+), 71 deletions(-)
> 
> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index 134cfc980b70..c651aad6f34b 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -1062,20 +1062,6 @@ of_fwnode_device_get_match_data(const struct fwnode_handle *fwnode,
>  	return of_device_get_match_data(dev);
>  }
>  
> -static bool of_is_ancestor_of(struct device_node *test_ancestor,
> -			      struct device_node *child)
> -{
> -	of_node_get(child);
> -	while (child) {
> -		if (child == test_ancestor) {
> -			of_node_put(child);
> -			return true;
> -		}
> -		child = of_get_next_parent(child);
> -	}
> -	return false;
> -}
> -
>  static struct device_node *of_get_compat_node(struct device_node *np)
>  {
>  	of_node_get(np);
> @@ -1106,71 +1092,27 @@ static struct device_node *of_get_compat_node_parent(struct device_node *np)
>  	return node;
>  }
>  
> -/**
> - * of_link_to_phandle - Add fwnode link to supplier from supplier phandle
> - * @con_np: consumer device tree node
> - * @sup_np: supplier device tree node
> - *
> - * Given a phandle to a supplier device tree node (@sup_np), this function
> - * finds the device that owns the supplier device tree node and creates a
> - * device link from @dev consumer device to the supplier device. This function
> - * doesn't create device links for invalid scenarios such as trying to create a
> - * link with a parent device as the consumer of its child device. In such
> - * cases, it returns an error.
> - *
> - * Returns:
> - * - 0 if fwnode link successfully created to supplier
> - * - -EINVAL if the supplier link is invalid and should not be created
> - * - -ENODEV if struct device will never be create for supplier
> - */
> -static int of_link_to_phandle(struct device_node *con_np,
> +static void of_link_to_phandle(struct device_node *con_np,
>  			      struct device_node *sup_np)
>  {
> -	struct device *sup_dev;
> -	struct device_node *tmp_np = sup_np;
> +	struct device_node *tmp_np = of_node_get(sup_np);
>  
> -	/*
> -	 * Find the device node that contains the supplier phandle.  It may be
> -	 * @sup_np or it may be an ancestor of @sup_np.
> -	 */
> -	sup_np = of_get_compat_node(sup_np);
> -	if (!sup_np) {
> -		pr_debug("Not linking %pOFP to %pOFP - No device\n",
> -			 con_np, tmp_np);
> -		return -ENODEV;
> -	}
> +	/* Check that sup_np and its ancestors are available. */
> +	while (tmp_np) {
> +		if (of_fwnode_handle(tmp_np)->dev) {
> +			of_node_put(tmp_np);
> +			break;
> +		}
>  
> -	/*
> -	 * Don't allow linking a device node as a consumer of one of its
> -	 * descendant nodes. By definition, a child node can't be a functional
> -	 * dependency for the parent node.
> -	 */
> -	if (of_is_ancestor_of(con_np, sup_np)) {
> -		pr_debug("Not linking %pOFP to %pOFP - is descendant\n",
> -			 con_np, sup_np);
> -		of_node_put(sup_np);
> -		return -EINVAL;
> -	}
> +		if (!of_device_is_available(tmp_np)) {
> +			of_node_put(tmp_np);
> +			return;
> +		}
>  
> -	/*
> -	 * Don't create links to "early devices" that won't have struct devices
> -	 * created for them.
> -	 */
> -	sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
> -	if (!sup_dev &&
> -	    (of_node_check_flag(sup_np, OF_POPULATED) ||
> -	     sup_np->fwnode.flags & FWNODE_FLAG_NOT_DEVICE)) {
> -		pr_debug("Not linking %pOFP to %pOFP - No struct device\n",
> -			 con_np, sup_np);
> -		of_node_put(sup_np);
> -		return -ENODEV;
> +		tmp_np = of_get_next_parent(tmp_np);
>  	}
> -	put_device(sup_dev);
>  
>  	fwnode_link_add(of_fwnode_handle(con_np), of_fwnode_handle(sup_np));

fwnode_link_add() returns int. Why is the return type of this function
changed to void?

> -	of_node_put(sup_np);
> -
> -	return 0;
>  }
>  
>  /**

On Mon, Jan 30, 2023 at 12:43 AM Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
>
> Hi Saravana,
>
> On Sat, Jan 28, 2023 at 8:19 AM Saravana Kannan <saravanak@google.com> wrote:
> > On Fri, Jan 27, 2023 at 12:11 AM Geert Uytterhoeven
> > <geert@linux-m68k.org> wrote:
> > > On Fri, Jan 27, 2023 at 1:11 AM Saravana Kannan <saravanak@google.com> wrote:
> > > > The OF_POPULATED flag was set to let fw_devlink know that the device
> > > > tree node will not have a struct device created for it. This information
> > > > is used by fw_devlink to avoid deferring the probe of consumers of this
> > > > device tree node.
> > > >
> > > > Let's use fwnode_dev_initialized() instead because it achieves the same
> > > > effect without using OF specific flags. This allows more generic code to
> > > > be written in driver core.
> > > >
> > > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > >
> > > Thanks for your patch!
> > >
> > > > --- a/drivers/soc/renesas/rcar-sysc.c
> > > > +++ b/drivers/soc/renesas/rcar-sysc.c
> > > > @@ -437,7 +437,7 @@ static int __init rcar_sysc_pd_init(void)
> > > >
> > > >         error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
> > > >         if (!error)
> > > > -               of_node_set_flag(np, OF_POPULATED);
> > > > +               fwnode_dev_initialized(&np->fwnode, true);
> > >
> > > As drivers/soc/renesas/rmobile-sysc.c is already using this method,
> > > it should work fine.
> > >
> > > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > > i.e. will queue in renesas-devel for v6.4.

I hope you meant queue it up for 6.3 and not 6.4?

> >
> > Thanks! Does that mean I should drop this from this series? If two
> > maintainers pick the same patch up, will it cause problems? I'm
> > eventually expecting this series to be picked up by Greg into
> > driver-core-next.
>
> Indeed. Patches for drivers/soc/renesas/ are supposed to go upstream
> through the renesas-devel and soc trees. This patch has no dependencies
> on anything else in the series (or vice versa), so there is no reason
> to deviate from that, and possibly cause conflicts later.

This series is supposed to fix a bunch of issues and I vaguely think
the series depends on this patch to work correctly on some Renesas
systems. You are my main renesas person, so it's probably some issue
you hit. Is you pick it up outside of this series I need to keep
asking folks to pick up two different patch threads. I don't have a
strong opinion, just a FYI. If you can take this patch soon, I don't
have any concerns.

> BTW, I will convert to of_node_to_fwnode() while applying.

Sounds good.

-Saravana

On Mon, Jan 30, 2023 at 12:56 AM Naresh Kamboju
<naresh.kamboju@linaro.org> wrote:
>
> Build test pass on arm, arm64, i386, mips, parisc, powerpc, riscv, s390, sh,
> sparc and x86_64.
>
> Boot and LTP smoke pass on qemu-arm64, qemu-armv7, qemu-i386 and qemu-x86_64.
> Boot failed on FVP.
>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
>
> Please refer following link for details of testing.
> FVP boot log failed.
> https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/lore_kernel_org_linux-devicetree_20230127001141_407071-1-saravanak_google_com/testrun/14389034/suite/boot/test/gcc-12-lkftconfig-64k_page_size/details/

Sudeep pointed me to what the issue might be. But it's strange that
you are hitting an issue now. I'm pretty sure I haven't changed this
part since v1. I'd also expect the limited assumptions I made to have
not been affected between v1 and v2.

Anyway, I'll look at this and fix it in v3.

-Saravana

On Mon, Jan 30, 2023 at 4:09 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
>
> Hi Saravana & Miquel.
>
> Sorry for the long response. I finally got access to my test device
> and tried this patch series.
>
> And unfortunately it didn't solve my issue. I'm still getting a
> hanging f1070000.ethernet dependency
> from the nvmem-cell mac@6 subnode.

Thanks for testing the series.

Btw, don't top post. It's frowned upon. Top post means your reply is
on the top before the email you are replying to. See how my first line
of reply in inline with your email I'm replying to?

>
> Here are related parts of my kernel log and device tree:
>
>
>     [    2.713302] device: 'mtd-0': device_add
>     [    2.719528] device: 'spi0': device_add
>     [    2.724180] device: 'spi0.0': device_add
>     [    2.728957] spi-nor spi0.0: mx66l51235f (65536 Kbytes)
>     [    2.735338] 7 fixed-partitions partitions found on MTD device spi0.0
>     [    2.741978] device:
> 'f1010600.spi:m25p80@0:partitions:partition@1': device_add
>     [    2.749636] Creating 7 MTD partitions on "spi0.0":
>     [    2.754564] 0x000000000000-0x000000080000 : "SPI.U_BOOT"
>     [    2.759981] device: 'mtd0': device_add
>     [    2.764323] device: 'mtd0': device_add
>     [    2.768280] device: 'mtd0ro': device_add
>     [    2.772624] 0x0000000a0000-0x0000000c0000 : "SPI.INV_INFO"
>     [    2.778218] device: 'mtd1': device_add
>     [    2.782549] device: 'mtd1': device_add
>     [    2.786582] device: 'mtd1ro': device_add
>     ...
>     [    5.426625] mvneta_bm f10c0000.bm: Buffer Manager for network
> controller enabled
>     [    5.492867] platform f1070000.ethernet: error -EPROBE_DEFER:
> wait for supplier mac@6
>     [    5.528636] device: 'Fixed MDIO bus.0': device_add
>     [    5.533726] device: 'fixed-0': device_add
>     [    5.547564] device: 'f1072004.mdio-eth-mii': device_add
>     [    5.616368] device: 'f1072004.mdio-eth-mii:00': device_add
>     [    5.645127] device: 'f1072004.mdio-eth-mii:1e': device_add
>     [    5.651530] devices_kset: Moving f1070000.ethernet to end of list
>     [    5.657948] platform f1070000.ethernet: error -EPROBE_DEFER:
> wait for supplier mac@6
>
>     spi@10600 {
>         m25p80@0 {
>             compatible = "mx66l51235l";
>
>             partitions {
>                 compatible = "fixed-partitions";
>
>                 partition@0 {
>                     label = "SPI.U_BOOT";
>                 };
>                 partition@1 {
>                     compatible = "nvmem-cells";
>                     label = "SPI.INV_INFO";
>                     macaddr: mac@6 {
>                         reg = <0x6 0x6>;
>                     };
>                 };
>                 ...
>             };
>         };
>     };
>
>     enet1: ethernet@70000 {
>         nvmem-cells = <&macaddr>;
>         nvmem-cell-names = "mac-address";
>         phy-mode = "rgmii";
>         phy = <&phy0>;
>     };
>
>
> Maybe I should provide some additional debug info?

I took a look at it and I think I know the issue. But it'll be good if
you can point me to the dts (not dtsi) file that corresponds to the
board you are seeing this issue on so I can double check my guess by
looking at the exact code/drivers.

The main problem/mistake is the nvmem framework is using a "struct
bus" instead of a "struct class" to keep a list of the nvmem devices.
And we can't change it now because it'd affect the sysfs paths
significantly and might break userspace ABI.

Can you try the patch at the end of this email under these
configurations and tell me which ones fail vs pass? I don't need logs
for any pass/failures.
1. On top of this series
2. Without this series
3. On top of the series but with the call to fwnode_dev_initialized() deleted?
4. Without this series, but with the call to fwnode_dev_initialized() deleted?

-Saravana

Sorry about tabs to spaces conversion. Email client issue.

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 321d7d63e068..23d94c0ecccf 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -752,6 +752,7 @@ static int nvmem_add_cells_from_of(struct
nvmem_device *nvmem)
 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 {
        struct nvmem_device *nvmem;
+       struct fwnode_handle *fwnode;
        int rval;

        if (!config->dev)
@@ -804,9 +805,18 @@ struct nvmem_device *nvmem_register(const struct
nvmem_config *config)
        nvmem->keepout = config->keepout;
        nvmem->nkeepout = config->nkeepout;
        if (config->of_node)
-               nvmem->dev.of_node = config->of_node;
+               fwnode = of_fwnode_handle(config->of_node);
        else if (!config->no_of_node)
-               nvmem->dev.of_node = config->dev->of_node;
+               fwnode = of_fwnode_handle(config->dev->of_node);
+       device_set_node(&nvmem->dev, fwnode);
+
+       /*
+        * If the fwnode doesn't have another device associated with it, mark
+        * the fwnode as initialized since no driver is going to bind to the
+        * nvmem.
+        */
+       if (fwnode && !fwnode->dev)
+               fwnode_dev_initialized(fwnode, true);

        switch (config->id) {
        case NVMEM_DEVID_NONE:

On Mon, Jan 30, 2023 at 10:15 AM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
>
> Hi Saravana,
>
> On Thu, Jan 26, 2023 at 04:11:36PM -0800, Saravana Kannan wrote:
> > The driver core now:
> > - Has the parent device of a supplier pick up the consumers if the
> >   supplier never has a device created for it.
> > - Ignores a supplier if the supplier has no parent device and will never
> >   be probed by a driver
> >
> > And already prevents creating a device link with the consumer as a
> > supplier of a parent.
> >
> > So, we no longer need to find the "compatible" node of the supplier or
> > do any other checks in of_link_to_phandle(). We simply need to make sure
> > that the supplier is available in DT.
> >
> > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > ---
> >  drivers/of/property.c | 84 +++++++------------------------------------
> >  1 file changed, 13 insertions(+), 71 deletions(-)
> >
> > diff --git a/drivers/of/property.c b/drivers/of/property.c
> > index 134cfc980b70..c651aad6f34b 100644
> > --- a/drivers/of/property.c
> > +++ b/drivers/of/property.c
> > @@ -1062,20 +1062,6 @@ of_fwnode_device_get_match_data(const struct fwnode_handle *fwnode,
> >       return of_device_get_match_data(dev);
> >  }
> >
> > -static bool of_is_ancestor_of(struct device_node *test_ancestor,
> > -                           struct device_node *child)
> > -{
> > -     of_node_get(child);
> > -     while (child) {
> > -             if (child == test_ancestor) {
> > -                     of_node_put(child);
> > -                     return true;
> > -             }
> > -             child = of_get_next_parent(child);
> > -     }
> > -     return false;
> > -}
> > -
> >  static struct device_node *of_get_compat_node(struct device_node *np)
> >  {
> >       of_node_get(np);
> > @@ -1106,71 +1092,27 @@ static struct device_node *of_get_compat_node_parent(struct device_node *np)
> >       return node;
> >  }
> >
> > -/**
> > - * of_link_to_phandle - Add fwnode link to supplier from supplier phandle
> > - * @con_np: consumer device tree node
> > - * @sup_np: supplier device tree node
> > - *
> > - * Given a phandle to a supplier device tree node (@sup_np), this function
> > - * finds the device that owns the supplier device tree node and creates a
> > - * device link from @dev consumer device to the supplier device. This function
> > - * doesn't create device links for invalid scenarios such as trying to create a
> > - * link with a parent device as the consumer of its child device. In such
> > - * cases, it returns an error.
> > - *
> > - * Returns:
> > - * - 0 if fwnode link successfully created to supplier
> > - * - -EINVAL if the supplier link is invalid and should not be created
> > - * - -ENODEV if struct device will never be create for supplier
> > - */
> > -static int of_link_to_phandle(struct device_node *con_np,
> > +static void of_link_to_phandle(struct device_node *con_np,
> >                             struct device_node *sup_np)
> >  {
> > -     struct device *sup_dev;
> > -     struct device_node *tmp_np = sup_np;
> > +     struct device_node *tmp_np = of_node_get(sup_np);
> >
> > -     /*
> > -      * Find the device node that contains the supplier phandle.  It may be
> > -      * @sup_np or it may be an ancestor of @sup_np.
> > -      */
> > -     sup_np = of_get_compat_node(sup_np);
> > -     if (!sup_np) {
> > -             pr_debug("Not linking %pOFP to %pOFP - No device\n",
> > -                      con_np, tmp_np);
> > -             return -ENODEV;
> > -     }
> > +     /* Check that sup_np and its ancestors are available. */
> > +     while (tmp_np) {
> > +             if (of_fwnode_handle(tmp_np)->dev) {
> > +                     of_node_put(tmp_np);
> > +                     break;
> > +             }
> >
> > -     /*
> > -      * Don't allow linking a device node as a consumer of one of its
> > -      * descendant nodes. By definition, a child node can't be a functional
> > -      * dependency for the parent node.
> > -      */
> > -     if (of_is_ancestor_of(con_np, sup_np)) {
> > -             pr_debug("Not linking %pOFP to %pOFP - is descendant\n",
> > -                      con_np, sup_np);
> > -             of_node_put(sup_np);
> > -             return -EINVAL;
> > -     }
> > +             if (!of_device_is_available(tmp_np)) {
> > +                     of_node_put(tmp_np);
> > +                     return;
> > +             }
> >
> > -     /*
> > -      * Don't create links to "early devices" that won't have struct devices
> > -      * created for them.
> > -      */
> > -     sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
> > -     if (!sup_dev &&
> > -         (of_node_check_flag(sup_np, OF_POPULATED) ||
> > -          sup_np->fwnode.flags & FWNODE_FLAG_NOT_DEVICE)) {
> > -             pr_debug("Not linking %pOFP to %pOFP - No struct device\n",
> > -                      con_np, sup_np);
> > -             of_node_put(sup_np);
> > -             return -ENODEV;
> > +             tmp_np = of_get_next_parent(tmp_np);
> >       }
> > -     put_device(sup_dev);
> >
> >       fwnode_link_add(of_fwnode_handle(con_np), of_fwnode_handle(sup_np));
>
> fwnode_link_add() returns int. Why is the return type of this function
> changed to void?

The return value of fwnode_link_add() was ignored even before this
patch. Since all other reasons for of_link_to_phandle() to fail are
gone, I'm switching it to void.

fwnode_link_add() is ignored because it can only fail due to -ENOMEM.
Not much to do in that case. We do our best and move on.

-Saravana

Hi Saravana,

On Mon, Jan 30, 2023 at 9:00 PM Saravana Kannan <saravanak@google.com> wrote:
> On Mon, Jan 30, 2023 at 12:43 AM Geert Uytterhoeven
> <geert@linux-m68k.org> wrote:
> > On Sat, Jan 28, 2023 at 8:19 AM Saravana Kannan <saravanak@google.com> wrote:
> > > On Fri, Jan 27, 2023 at 12:11 AM Geert Uytterhoeven
> > > <geert@linux-m68k.org> wrote:
> > > > On Fri, Jan 27, 2023 at 1:11 AM Saravana Kannan <saravanak@google.com> wrote:
> > > > > The OF_POPULATED flag was set to let fw_devlink know that the device
> > > > > tree node will not have a struct device created for it. This information
> > > > > is used by fw_devlink to avoid deferring the probe of consumers of this
> > > > > device tree node.
> > > > >
> > > > > Let's use fwnode_dev_initialized() instead because it achieves the same
> > > > > effect without using OF specific flags. This allows more generic code to
> > > > > be written in driver core.
> > > > >
> > > > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > > >
> > > > Thanks for your patch!
> > > >
> > > > > --- a/drivers/soc/renesas/rcar-sysc.c
> > > > > +++ b/drivers/soc/renesas/rcar-sysc.c
> > > > > @@ -437,7 +437,7 @@ static int __init rcar_sysc_pd_init(void)
> > > > >
> > > > >         error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
> > > > >         if (!error)
> > > > > -               of_node_set_flag(np, OF_POPULATED);
> > > > > +               fwnode_dev_initialized(&np->fwnode, true);
> > > >
> > > > As drivers/soc/renesas/rmobile-sysc.c is already using this method,
> > > > it should work fine.
> > > >
> > > > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > > > i.e. will queue in renesas-devel for v6.4.
>
> I hope you meant queue it up for 6.3 and not 6.4?

V6.4.
The deadline for submitting pull requests for the soc tree is rc6.
Sorry, your series was posted too late to make that.

> > > Thanks! Does that mean I should drop this from this series? If two
> > > maintainers pick the same patch up, will it cause problems? I'm
> > > eventually expecting this series to be picked up by Greg into
> > > driver-core-next.
> >
> > Indeed. Patches for drivers/soc/renesas/ are supposed to go upstream
> > through the renesas-devel and soc trees. This patch has no dependencies
> > on anything else in the series (or vice versa), so there is no reason
> > to deviate from that, and possibly cause conflicts later.
>
> This series is supposed to fix a bunch of issues and I vaguely think
> the series depends on this patch to work correctly on some Renesas
> systems. You are my main renesas person, so it's probably some issue
> you hit. Is you pick it up outside of this series I need to keep
> asking folks to pick up two different patch threads. I don't have a
> strong opinion, just a FYI. If you can take this patch soon, I don't
> have any concerns.

Oh right, you do remove OF_POPULATED handling in
"[PATCH v2 09/11] of: property: Simplify of_link_to_phandle()".
It might be wise to postpone that removal, as after your series,
there are stillseveral users left, some of them might be impacted.

I do plan to test your full series on all my boards, but probably that
won't happen this week.

> > BTW, I will convert to of_node_to_fwnode() while applying.
>
> Sounds good.

If you still want this to land in v6,3 (with the of_node_to_fwnode()
conversion):
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Hi Saravana,

On Mon, Jan 30, 2023 at 03:03:01PM -0800, Saravana Kannan wrote:
> On Mon, Jan 30, 2023 at 12:56 AM Naresh Kamboju
> <naresh.kamboju@linaro.org> wrote:
> >
> > Build test pass on arm, arm64, i386, mips, parisc, powerpc, riscv, s390, sh,
> > sparc and x86_64.
> >
> > Boot and LTP smoke pass on qemu-arm64, qemu-armv7, qemu-i386 and qemu-x86_64.
> > Boot failed on FVP.
> >
> > Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> >
> > Please refer following link for details of testing.
> > FVP boot log failed.
> > https://qa-reports.linaro.org/~anders.roxell/linux-mainline-patches/build/lore_kernel_org_linux-devicetree_20230127001141_407071-1-saravanak_google_com/testrun/14389034/suite/boot/test/gcc-12-lkftconfig-64k_page_size/details/
>
> Sudeep pointed me to what the issue might be. But it's strange that
> you are hitting an issue now. I'm pretty sure I haven't changed this
> part since v1. I'd also expect the limited assumptions I made to have
> not been affected between v1 and v2.
>

Sorry I hadn't seen or tested v1.

FYI The fwnode non-NULL check as in your nvmem diff/suggestion and the diff I
replied on the gpiolib patch thread fixes the issues.

> Anyway, I'll look at this and fix it in v3.
>

If you add that fwnode check, feel free to add my tested by.

--
Regards,
Sudeep

Hi Saravana,

> Can you try the patch at the end of this email under these
> configurations and tell me which ones fail vs pass? I don't need logs

I did these tests and here is the results:

1. On top of this series - Not works
2. Without this series    - Works
3. On top of the series with the fwnode_dev_initialized() deleted - Not works
4. Without this series, with the fwnode_dev_initialized() deleted  - Works

So your nvmem/core.c patch helps only when it is applied without the series.
But despite the fact that this helps to avoid getting stuck at probing
my ethernet device, there is still regression.

When the ethernet module is loaded it takes a lot of time to drop dependency
from the nvmem-cell with mac address.

Please look at the kernel logs below.

The first log corresponds to kernel with your nvmem/core.c patch:

    [    0.036462] ethernet@70000 Linked as a fwnode consumer to
clock-gating-control@1821c
    [    0.036572] ethernet@70000 Linked as a fwnode consumer to partition@1
    [    0.045596] device: 'f1070000.ethernet': device_add
    [    0.045854] ethernet@70000 Dropping the fwnode link to
clock-gating-control@1821c
    [    0.114990] device:
'platform:f1010600.spi:m25p80@0:partitions:partition@1--platform:f1070000.ethernet':
device_add
    [    0.115266] devices_kset: Moving f1070000.ethernet to end of list
    [    0.115308] platform f1070000.ethernet: Linked as a consumer to
f1010600.spi:m25p80@0:partitions:partition@1
    [    0.115345] ethernet@70000 Dropping the fwnode link to partition@1
    [    1.968232] platform f1070000.ethernet: error -EPROBE_DEFER:
supplier f1010600.spi:m25p80@0:partitions:partition@1 not ready
    [    2.088696] devices_kset: Moving f1070000.ethernet to end of list
    [    2.088988] platform f1070000.ethernet: error -EPROBE_DEFER:
supplier f1010600.spi:m25p80@0:partitions:partition@1 not ready
    [    2.152411] devices_kset: Moving f1070000.ethernet to end of list
    [    2.152735] platform f1070000.ethernet: error -EPROBE_DEFER:
supplier f1010600.spi:m25p80@0:partitions:partition@1 not ready
    [    2.153870] devices_kset: Moving f1070000.ethernet to end of list
    [    2.154152] platform f1070000.ethernet: error -EPROBE_DEFER:
supplier f1010600.spi:m25p80@0:partitions:partition@1 not ready
    [    2.644950] devices_kset: Moving f1070000.ethernet to end of list
    [    2.645282] platform f1070000.ethernet: error -EPROBE_DEFER:
supplier f1010600.spi:m25p80@0:partitions:partition@1 not ready
    [    3.169218] devices_kset: Moving f1070000.ethernet to end of list
    [    3.169506] platform f1070000.ethernet: error -EPROBE_DEFER:
supplier f1010600.spi:m25p80@0:partitions:partition@1 not ready
    [    3.170444] devices_kset: Moving f1070000.ethernet to end of list
    [    3.170721] platform f1070000.ethernet: error -EPROBE_DEFER:
supplier f1010600.spi:m25p80@0:partitions:partition@1 not ready
    [    3.419068] devices_kset: Moving f1070000.ethernet to end of list
    [    3.419359] platform f1070000.ethernet: error -EPROBE_DEFER:
supplier f1010600.spi:m25p80@0:partitions:partition@1 not ready
    [    3.521275] devices_kset: Moving f1070000.ethernet to end of list
    [    3.521564] platform f1070000.ethernet: error -EPROBE_DEFER:
supplier f1010600.spi:m25p80@0:partitions:partition@1 not ready
    [    3.639196] devices_kset: Moving f1070000.ethernet to end of list
    [    3.639532] platform f1070000.ethernet: error -EPROBE_DEFER:
supplier f1010600.spi:m25p80@0:partitions:partition@1 not ready
    [   13.960144] platform f1070000.ethernet: Relaxing link with
f1010600.spi:m25p80@0:partitions:partition@1
    [   13.960260] devices_kset: Moving f1070000.ethernet to end of list
    [   13.971735] device: 'eth0': device_add
    [   13.974140] mvneta f1070000.ethernet eth0: Using device tree
mac address de:fa:ce:db:ab:e1
    [   13.974275] mvneta f1070000.ethernet: Dropping the link to
f1010600.spi:m25p80@0:partitions:partition@1
    [   13.974318] device:
'platform:f1010600.spi:m25p80@0:partitions:partition@1--platform:f1070000.ethernet':
device_unregister

It took around 13 seconds to obtain a mac from nvmem-cell and bring up
f1070000.ethernet


And here is the second log which corresponds to kernel without your
nvmem/core.c patch but also with reverted change 'bcdf0315':

    [    0.036285] ethernet@70000 Linked as a fwnode consumer to
clock-gating-control@1821c
    [    0.036395] ethernet@70000 Linked as a fwnode consumer to partition@1
    [    0.045416] device: 'f1070000.ethernet': device_add
    [    0.045674] ethernet@70000 Dropping the fwnode link to
clock-gating-control@1821c
    [    0.116136] ethernet@70000 Dropping the fwnode link to partition@1
    [    1.977060] device: 'eth0': device_add
    [    1.979145] mvneta f1070000.ethernet eth0: Using device tree
mac address de:fa:ce:db:ab:e1

It took around 1.5 second to obtain a mac from nvmem-cell

P.S. Your nvmem patch definitely helps to avoid a device probe stuck
but look like it is not best way to solve a problem which we discussed
in the MTD thread.

P.P.S. Also I don't know why your nvmem-cell patch doesn't help when it was
applied on top of this series. Maybe I missed something.

On Thu, Feb 2, 2023 at 9:36 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
>
> Hi Saravana,
>
> > Can you try the patch at the end of this email under these
> > configurations and tell me which ones fail vs pass? I don't need logs
>
> I did these tests and here is the results:

Did you hand edit the In-Reply-To: in the header? Because in the
thread you are reply to the wrong email, but the context in your email
seems to be from the right email.

For example, see how your reply isn't under the email you are replying
to in this thread overview:
https://lore.kernel.org/lkml/20230127001141.407071-1-saravanak@google.com/#r

> 1. On top of this series - Not works
> 2. Without this series    - Works
> 3. On top of the series with the fwnode_dev_initialized() deleted - Not works
> 4. Without this series, with the fwnode_dev_initialized() deleted  - Works
>
> So your nvmem/core.c patch helps only when it is applied without the series.
> But despite the fact that this helps to avoid getting stuck at probing
> my ethernet device, there is still regression.
>
> When the ethernet module is loaded it takes a lot of time to drop dependency
> from the nvmem-cell with mac address.
>
> Please look at the kernel logs below.

The kernel logs below really aren't that useful for me in their
current state. See more below.

---8<---- <snip> --->8----

> P.S. Your nvmem patch definitely helps to avoid a device probe stuck
> but look like it is not best way to solve a problem which we discussed
> in the MTD thread.
>
> P.P.S. Also I don't know why your nvmem-cell patch doesn't help when it was
> applied on top of this series. Maybe I missed something.

Yeah, I'm not too sure if the test was done correctly. You also didn't
answer my question about the dts from my earlier email.
https://lore.kernel.org/lkml/CAGETcx8FpmbaRm2CCwqt3BRBpgbogwP5gNB+iA5OEtuxWVTNLA@mail.gmail.com/#t

So, can you please retest config 1 with all pr_debug and dev_dbg in
drivers/core/base.c changed to the _info variants? And then share the
kernel log from the beginning of boot? Maybe attach it to the email so
it doesn't get word wrapped by your email client. And please point me
to the .dts that corresponds to your board. Without that, I can't
debug much.

Thanks,
Saravana

пт, 3 февр. 2023 г. в 09:07, Saravana Kannan <saravanak@google.com>:
>
> On Thu, Feb 2, 2023 at 9:36 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> >
> > Hi Saravana,
> >
> > > Can you try the patch at the end of this email under these
> > > configurations and tell me which ones fail vs pass? I don't need logs
> >
> > I did these tests and here is the results:
>
> Did you hand edit the In-Reply-To: in the header? Because in the
> thread you are reply to the wrong email, but the context in your email
> seems to be from the right email.
>
> For example, see how your reply isn't under the email you are replying
> to in this thread overview:
> https://lore.kernel.org/lkml/20230127001141.407071-1-saravanak@google.com/#r
>
> > 1. On top of this series - Not works
> > 2. Without this series    - Works
> > 3. On top of the series with the fwnode_dev_initialized() deleted - Not works
> > 4. Without this series, with the fwnode_dev_initialized() deleted  - Works
> >
> > So your nvmem/core.c patch helps only when it is applied without the series.
> > But despite the fact that this helps to avoid getting stuck at probing
> > my ethernet device, there is still regression.
> >
> > When the ethernet module is loaded it takes a lot of time to drop dependency
> > from the nvmem-cell with mac address.
> >
> > Please look at the kernel logs below.
>
> The kernel logs below really aren't that useful for me in their
> current state. See more below.
>
> ---8<---- <snip> --->8----
>
> > P.S. Your nvmem patch definitely helps to avoid a device probe stuck
> > but look like it is not best way to solve a problem which we discussed
> > in the MTD thread.
> >
> > P.P.S. Also I don't know why your nvmem-cell patch doesn't help when it was
> > applied on top of this series. Maybe I missed something.
>
> Yeah, I'm not too sure if the test was done correctly. You also didn't
> answer my question about the dts from my earlier email.
> https://lore.kernel.org/lkml/CAGETcx8FpmbaRm2CCwqt3BRBpgbogwP5gNB+iA5OEtuxWVTNLA@mail.gmail.com/#t
>
> So, can you please retest config 1 with all pr_debug and dev_dbg in
> drivers/core/base.c changed to the _info variants? And then share the
> kernel log from the beginning of boot? Maybe attach it to the email so
> it doesn't get word wrapped by your email client. And please point me
> to the .dts that corresponds to your board. Without that, I can't
> debug much.
>
> Thanks,
> Saravana

> Did you hand edit the In-Reply-To: in the header? Because in the
> thread you are reply to the wrong email, but the context in your email
> seems to be from the right email.

Sorry for that, it seems like I accidently deleted it.

> So, can you please retest config 1 with all pr_debug and dev_dbg in
> drivers/core/base.c changed to the _info variants? And then share the
> kernel log from the beginning of boot? Maybe attach it to the email so
> it doesn't get word wrapped by your email client. And please point me
> to the .dts that corresponds to your board. Without that, I can't
> debug much.

Ok, I retested config 1 with all _debug logs changed to the _info. I
added the kernel log and the dts file to the attachment of this email.

On Tue, Jan 31, 2023 at 12:14 AM Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
>
> Hi Saravana,
>
> On Mon, Jan 30, 2023 at 9:00 PM Saravana Kannan <saravanak@google.com> wrote:
> > On Mon, Jan 30, 2023 at 12:43 AM Geert Uytterhoeven
> > <geert@linux-m68k.org> wrote:
> > > On Sat, Jan 28, 2023 at 8:19 AM Saravana Kannan <saravanak@google.com> wrote:
> > > > On Fri, Jan 27, 2023 at 12:11 AM Geert Uytterhoeven
> > > > <geert@linux-m68k.org> wrote:
> > > > > On Fri, Jan 27, 2023 at 1:11 AM Saravana Kannan <saravanak@google.com> wrote:
> > > > > > The OF_POPULATED flag was set to let fw_devlink know that the device
> > > > > > tree node will not have a struct device created for it. This information
> > > > > > is used by fw_devlink to avoid deferring the probe of consumers of this
> > > > > > device tree node.
> > > > > >
> > > > > > Let's use fwnode_dev_initialized() instead because it achieves the same
> > > > > > effect without using OF specific flags. This allows more generic code to
> > > > > > be written in driver core.
> > > > > >
> > > > > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > > > >
> > > > > Thanks for your patch!
> > > > >
> > > > > > --- a/drivers/soc/renesas/rcar-sysc.c
> > > > > > +++ b/drivers/soc/renesas/rcar-sysc.c
> > > > > > @@ -437,7 +437,7 @@ static int __init rcar_sysc_pd_init(void)
> > > > > >
> > > > > >         error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
> > > > > >         if (!error)
> > > > > > -               of_node_set_flag(np, OF_POPULATED);
> > > > > > +               fwnode_dev_initialized(&np->fwnode, true);
> > > > >
> > > > > As drivers/soc/renesas/rmobile-sysc.c is already using this method,
> > > > > it should work fine.
> > > > >
> > > > > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > > > > i.e. will queue in renesas-devel for v6.4.
> >
> > I hope you meant queue it up for 6.3 and not 6.4?
>
> V6.4.
> The deadline for submitting pull requests for the soc tree is rc6.
> Sorry, your series was posted too late to make that.
>
> > > > Thanks! Does that mean I should drop this from this series? If two
> > > > maintainers pick the same patch up, will it cause problems? I'm
> > > > eventually expecting this series to be picked up by Greg into
> > > > driver-core-next.
> > >
> > > Indeed. Patches for drivers/soc/renesas/ are supposed to go upstream
> > > through the renesas-devel and soc trees. This patch has no dependencies
> > > on anything else in the series (or vice versa), so there is no reason
> > > to deviate from that, and possibly cause conflicts later.
> >
> > This series is supposed to fix a bunch of issues and I vaguely think
> > the series depends on this patch to work correctly on some Renesas
> > systems. You are my main renesas person, so it's probably some issue
> > you hit. Is you pick it up outside of this series I need to keep
> > asking folks to pick up two different patch threads. I don't have a
> > strong opinion, just a FYI. If you can take this patch soon, I don't
> > have any concerns.
>
> Oh right, you do remove OF_POPULATED handling in
> "[PATCH v2 09/11] of: property: Simplify of_link_to_phandle()".
> It might be wise to postpone that removal, as after your series,
> there are stillseveral users left, some of them might be impacted.
>
> I do plan to test your full series on all my boards, but probably that
> won't happen this week.
>
> > > BTW, I will convert to of_node_to_fwnode() while applying.
> >
> > Sounds good.
>
> If you still want this to land in v6,3 (with the of_node_to_fwnode()
> conversion):
> Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
>

Yeah, let me try to land this in 6.3 with the series.

-Saravana

On Fri, Feb 3, 2023 at 1:39 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
>
> пт, 3 февр. 2023 г. в 09:07, Saravana Kannan <saravanak@google.com>:
> >
> > On Thu, Feb 2, 2023 at 9:36 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> > >
> > > Hi Saravana,
> > >
> > > > Can you try the patch at the end of this email under these
> > > > configurations and tell me which ones fail vs pass? I don't need logs
> > >
> > > I did these tests and here is the results:
> >
> > Did you hand edit the In-Reply-To: in the header? Because in the
> > thread you are reply to the wrong email, but the context in your email
> > seems to be from the right email.
> >
> > For example, see how your reply isn't under the email you are replying
> > to in this thread overview:
> > https://lore.kernel.org/lkml/20230127001141.407071-1-saravanak@google.com/#r
> >
> > > 1. On top of this series - Not works
> > > 2. Without this series    - Works
> > > 3. On top of the series with the fwnode_dev_initialized() deleted - Not works
> > > 4. Without this series, with the fwnode_dev_initialized() deleted  - Works
> > >
> > > So your nvmem/core.c patch helps only when it is applied without the series.
> > > But despite the fact that this helps to avoid getting stuck at probing
> > > my ethernet device, there is still regression.
> > >
> > > When the ethernet module is loaded it takes a lot of time to drop dependency
> > > from the nvmem-cell with mac address.
> > >
> > > Please look at the kernel logs below.
> >
> > The kernel logs below really aren't that useful for me in their
> > current state. See more below.
> >
> > ---8<---- <snip> --->8----
> >
> > > P.S. Your nvmem patch definitely helps to avoid a device probe stuck
> > > but look like it is not best way to solve a problem which we discussed
> > > in the MTD thread.
> > >
> > > P.P.S. Also I don't know why your nvmem-cell patch doesn't help when it was
> > > applied on top of this series. Maybe I missed something.
> >
> > Yeah, I'm not too sure if the test was done correctly. You also didn't
> > answer my question about the dts from my earlier email.
> > https://lore.kernel.org/lkml/CAGETcx8FpmbaRm2CCwqt3BRBpgbogwP5gNB+iA5OEtuxWVTNLA@mail.gmail.com/#t
> >
> > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > drivers/core/base.c changed to the _info variants? And then share the
> > kernel log from the beginning of boot? Maybe attach it to the email so
> > it doesn't get word wrapped by your email client. And please point me
> > to the .dts that corresponds to your board. Without that, I can't
> > debug much.
> >
> > Thanks,
> > Saravana
>
> > Did you hand edit the In-Reply-To: in the header? Because in the
> > thread you are reply to the wrong email, but the context in your email
> > seems to be from the right email.
>
> Sorry for that, it seems like I accidently deleted it.
>
> > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > drivers/core/base.c changed to the _info variants? And then share the
> > kernel log from the beginning of boot? Maybe attach it to the email so
> > it doesn't get word wrapped by your email client. And please point me
> > to the .dts that corresponds to your board. Without that, I can't
> > debug much.
>
> Ok, I retested config 1 with all _debug logs changed to the _info. I
> added the kernel log and the dts file to the attachment of this email.

Ah, so your device is not supported/present upstream? Even though it's
not upstream, I'll help fix this because it should fix what I believe
are unreported issues in upstream.

Ok I know why configs 1 - 4 behaved the way they did and why my test
patch didn't help.

After staring at mtd/nvmem code for a few hours I think mtd/nvmem
interaction is kind of a mess. mtd core creates "partition" platform
devices (including for nvmem-cells) that are probed by drivers in
drivers/nvmem. However, there's no driver for "nvmem-cells" partition
platform device. However, the nvmem core creates nvmem_device when
nvmem_register() is called by MTD or these partition platform devices
created by MTD. But these nvmem_devices are added to a nvmem_bus but
the bus has no means to even register a driver (it should really be a
nvmem_class and not nvmem_bus). And the nvmem_device sometimes points
to the DT node of the MTD device or sometimes the partition platform
devices or maybe no DT node at all.

So it's a mess of multiple devices pointing to the same DT node with
no clear way to identify which ones will point to a DT node and which
ones will probe and which ones won't. In the future, we shouldn't
allow adding new compatible strings for partitions for which we don't
plan on adding nvmem drivers.

Can you give the patch at the end of the email a shot? It should fix
the issue with this series and without this series. It just avoids
this whole mess by not creating useless platform device for
nvmem-cells compatible DT nodes.

Thanks,
Saravana

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index d442fa94c872..88a213f4d651 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -577,6 +577,7 @@ static int mtd_part_of_parse(struct mtd_info *master,
 {
        struct mtd_part_parser *parser;
        struct device_node *np;
+       struct device_node *child;
        struct property *prop;
        struct device *dev;
        const char *compat;
@@ -594,6 +595,10 @@ static int mtd_part_of_parse(struct mtd_info *master,
        else
                np = of_get_child_by_name(np, "partitions");

+       for_each_child_of_node(np, child)
+               if (of_device_is_compatible(child, "nvmem-cells"))
+                       of_node_set_flag(child, OF_POPULATED);
+
        of_property_for_each_string(np, "compatible", prop, compat) {
                parser = mtd_part_get_compatible_parser(compat);
                if (!parser)

On Sun, Feb 5, 2023 at 5:32 PM Saravana Kannan <saravanak@google.com> wrote:
>
> On Fri, Feb 3, 2023 at 1:39 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> >
> > пт, 3 февр. 2023 г. в 09:07, Saravana Kannan <saravanak@google.com>:
> > >
> > > On Thu, Feb 2, 2023 at 9:36 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> > > >
> > > > Hi Saravana,
> > > >
> > > > > Can you try the patch at the end of this email under these
> > > > > configurations and tell me which ones fail vs pass? I don't need logs
> > > >
> > > > I did these tests and here is the results:
> > >
> > > Did you hand edit the In-Reply-To: in the header? Because in the
> > > thread you are reply to the wrong email, but the context in your email
> > > seems to be from the right email.
> > >
> > > For example, see how your reply isn't under the email you are replying
> > > to in this thread overview:
> > > https://lore.kernel.org/lkml/20230127001141.407071-1-saravanak@google.com/#r
> > >
> > > > 1. On top of this series - Not works
> > > > 2. Without this series    - Works
> > > > 3. On top of the series with the fwnode_dev_initialized() deleted - Not works
> > > > 4. Without this series, with the fwnode_dev_initialized() deleted  - Works
> > > >
> > > > So your nvmem/core.c patch helps only when it is applied without the series.
> > > > But despite the fact that this helps to avoid getting stuck at probing
> > > > my ethernet device, there is still regression.
> > > >
> > > > When the ethernet module is loaded it takes a lot of time to drop dependency
> > > > from the nvmem-cell with mac address.
> > > >
> > > > Please look at the kernel logs below.
> > >
> > > The kernel logs below really aren't that useful for me in their
> > > current state. See more below.
> > >
> > > ---8<---- <snip> --->8----
> > >
> > > > P.S. Your nvmem patch definitely helps to avoid a device probe stuck
> > > > but look like it is not best way to solve a problem which we discussed
> > > > in the MTD thread.
> > > >
> > > > P.P.S. Also I don't know why your nvmem-cell patch doesn't help when it was
> > > > applied on top of this series. Maybe I missed something.
> > >
> > > Yeah, I'm not too sure if the test was done correctly. You also didn't
> > > answer my question about the dts from my earlier email.
> > > https://lore.kernel.org/lkml/CAGETcx8FpmbaRm2CCwqt3BRBpgbogwP5gNB+iA5OEtuxWVTNLA@mail.gmail.com/#t
> > >
> > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > drivers/core/base.c changed to the _info variants? And then share the
> > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > it doesn't get word wrapped by your email client. And please point me
> > > to the .dts that corresponds to your board. Without that, I can't
> > > debug much.
> > >
> > > Thanks,
> > > Saravana
> >
> > > Did you hand edit the In-Reply-To: in the header? Because in the
> > > thread you are reply to the wrong email, but the context in your email
> > > seems to be from the right email.
> >
> > Sorry for that, it seems like I accidently deleted it.
> >
> > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > drivers/core/base.c changed to the _info variants? And then share the
> > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > it doesn't get word wrapped by your email client. And please point me
> > > to the .dts that corresponds to your board. Without that, I can't
> > > debug much.
> >
> > Ok, I retested config 1 with all _debug logs changed to the _info. I
> > added the kernel log and the dts file to the attachment of this email.
>
> Ah, so your device is not supported/present upstream? Even though it's
> not upstream, I'll help fix this because it should fix what I believe
> are unreported issues in upstream.
>
> Ok I know why configs 1 - 4 behaved the way they did and why my test
> patch didn't help.
>
> After staring at mtd/nvmem code for a few hours I think mtd/nvmem
> interaction is kind of a mess. mtd core creates "partition" platform
> devices (including for nvmem-cells) that are probed by drivers in
> drivers/nvmem. However, there's no driver for "nvmem-cells" partition
> platform device. However, the nvmem core creates nvmem_device when
> nvmem_register() is called by MTD or these partition platform devices
> created by MTD. But these nvmem_devices are added to a nvmem_bus but
> the bus has no means to even register a driver (it should really be a
> nvmem_class and not nvmem_bus). And the nvmem_device sometimes points
> to the DT node of the MTD device or sometimes the partition platform
> devices or maybe no DT node at all.
>
> So it's a mess of multiple devices pointing to the same DT node with
> no clear way to identify which ones will point to a DT node and which
> ones will probe and which ones won't. In the future, we shouldn't
> allow adding new compatible strings for partitions for which we don't
> plan on adding nvmem drivers.
>
> Can you give the patch at the end of the email a shot? It should fix
> the issue with this series and without this series. It just avoids
> this whole mess by not creating useless platform device for
> nvmem-cells compatible DT nodes.

Actually, without this series, the patch below will need an additional
line of code inside the if block:
fwnode_dev_initialized(of_fwnode_handle(child), true);

-Saravana

>
> Thanks,
> Saravana
>
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index d442fa94c872..88a213f4d651 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -577,6 +577,7 @@ static int mtd_part_of_parse(struct mtd_info *master,
>  {
>         struct mtd_part_parser *parser;
>         struct device_node *np;
> +       struct device_node *child;
>         struct property *prop;
>         struct device *dev;
>         const char *compat;
> @@ -594,6 +595,10 @@ static int mtd_part_of_parse(struct mtd_info *master,
>         else
>                 np = of_get_child_by_name(np, "partitions");
>
> +       for_each_child_of_node(np, child)
> +               if (of_device_is_compatible(child, "nvmem-cells"))
> +                       of_node_set_flag(child, OF_POPULATED);
> +
>         of_property_for_each_string(np, "compatible", prop, compat) {
>                 parser = mtd_part_get_compatible_parser(compat);
>                 if (!parser)

Hi Saravana,

+ Srinivas, nvmem maintainer

saravanak@google.com wrote on Sun, 5 Feb 2023 17:32:57 -0800:

> On Fri, Feb 3, 2023 at 1:39 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> >
> > пт, 3 февр. 2023 г. в 09:07, Saravana Kannan <saravanak@google.com>:  
> > >
> > > On Thu, Feb 2, 2023 at 9:36 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:  
> > > >
> > > > Hi Saravana,
> > > >  
> > > > > Can you try the patch at the end of this email under these
> > > > > configurations and tell me which ones fail vs pass? I don't need logs  
> > > >
> > > > I did these tests and here is the results:  
> > >
> > > Did you hand edit the In-Reply-To: in the header? Because in the
> > > thread you are reply to the wrong email, but the context in your email
> > > seems to be from the right email.
> > >
> > > For example, see how your reply isn't under the email you are replying
> > > to in this thread overview:
> > > https://lore.kernel.org/lkml/20230127001141.407071-1-saravanak@google.com/#r
> > >  
> > > > 1. On top of this series - Not works
> > > > 2. Without this series    - Works
> > > > 3. On top of the series with the fwnode_dev_initialized() deleted - Not works
> > > > 4. Without this series, with the fwnode_dev_initialized() deleted  - Works
> > > >
> > > > So your nvmem/core.c patch helps only when it is applied without the series.
> > > > But despite the fact that this helps to avoid getting stuck at probing
> > > > my ethernet device, there is still regression.
> > > >
> > > > When the ethernet module is loaded it takes a lot of time to drop dependency
> > > > from the nvmem-cell with mac address.
> > > >
> > > > Please look at the kernel logs below.  
> > >
> > > The kernel logs below really aren't that useful for me in their
> > > current state. See more below.
> > >
> > > ---8<---- <snip> --->8----
> > >  
> > > > P.S. Your nvmem patch definitely helps to avoid a device probe stuck
> > > > but look like it is not best way to solve a problem which we discussed
> > > > in the MTD thread.
> > > >
> > > > P.P.S. Also I don't know why your nvmem-cell patch doesn't help when it was
> > > > applied on top of this series. Maybe I missed something.  
> > >
> > > Yeah, I'm not too sure if the test was done correctly. You also didn't
> > > answer my question about the dts from my earlier email.
> > > https://lore.kernel.org/lkml/CAGETcx8FpmbaRm2CCwqt3BRBpgbogwP5gNB+iA5OEtuxWVTNLA@mail.gmail.com/#t
> > >
> > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > drivers/core/base.c changed to the _info variants? And then share the
> > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > it doesn't get word wrapped by your email client. And please point me
> > > to the .dts that corresponds to your board. Without that, I can't
> > > debug much.
> > >
> > > Thanks,
> > > Saravana  
> >  
> > > Did you hand edit the In-Reply-To: in the header? Because in the
> > > thread you are reply to the wrong email, but the context in your email
> > > seems to be from the right email.  
> >
> > Sorry for that, it seems like I accidently deleted it.
> >  
> > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > drivers/core/base.c changed to the _info variants? And then share the
> > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > it doesn't get word wrapped by your email client. And please point me
> > > to the .dts that corresponds to your board. Without that, I can't
> > > debug much.  
> >
> > Ok, I retested config 1 with all _debug logs changed to the _info. I
> > added the kernel log and the dts file to the attachment of this email.  
> 
> Ah, so your device is not supported/present upstream? Even though it's
> not upstream, I'll help fix this because it should fix what I believe
> are unreported issues in upstream.
> 
> Ok I know why configs 1 - 4 behaved the way they did and why my test
> patch didn't help.
> 
> After staring at mtd/nvmem code for a few hours I think mtd/nvmem
> interaction is kind of a mess.

nvmem is a recent subsystem but mtd carries a lot of legacy stuff we
cannot really re-wire without breaking users, so nvmem on top of mtd
of course inherit from the fragile designs in place.

> mtd core creates "partition" platform
> devices (including for nvmem-cells) that are probed by drivers in
> drivers/nvmem. However, there's no driver for "nvmem-cells" partition
> platform device. However, the nvmem core creates nvmem_device when
> nvmem_register() is called by MTD or these partition platform devices
> created by MTD. But these nvmem_devices are added to a nvmem_bus but
> the bus has no means to even register a driver (it should really be a
> nvmem_class and not nvmem_bus).

Srinivas, do you think we could change this?

> And the nvmem_device sometimes points
> to the DT node of the MTD device or sometimes the partition platform
> devices or maybe no DT node at all.

I guess this comes from the fact that this is not strongly defined in
mtd and depends on the situation (not mentioning 20 years of history
there as well). "mtd" is a bit inconsistent on what it means. Older
designs mixed: controllers, ECC engines when relevant and memories;
while these three components are completely separated. Hence
sometimes the mtd device ends up being the top level controller,
sometimes it's just one partition...

But I'm surprised not all of them point to a DT node. Could you show us
an example? Because that might likely be unexpected (or perhaps I am
missing something).

> So it's a mess of multiple devices pointing to the same DT node with
> no clear way to identify which ones will point to a DT node and which
> ones will probe and which ones won't. In the future, we shouldn't
> allow adding new compatible strings for partitions for which we don't
> plan on adding nvmem drivers.
>
> Can you give the patch at the end of the email a shot? It should fix
> the issue with this series and without this series. It just avoids
> this whole mess by not creating useless platform device for
> nvmem-cells compatible DT nodes.

Thanks a lot for your help.

> 
> Thanks,
> Saravana
> 
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index d442fa94c872..88a213f4d651 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -577,6 +577,7 @@ static int mtd_part_of_parse(struct mtd_info *master,
>  {
>         struct mtd_part_parser *parser;
>         struct device_node *np;
> +       struct device_node *child;
>         struct property *prop;
>         struct device *dev;
>         const char *compat;
> @@ -594,6 +595,10 @@ static int mtd_part_of_parse(struct mtd_info *master,
>         else
>                 np = of_get_child_by_name(np, "partitions");
> 
> +       for_each_child_of_node(np, child)
> +               if (of_device_is_compatible(child, "nvmem-cells"))
> +                       of_node_set_flag(child, OF_POPULATED);

What about a comment explaining why we need that in the final patch
(with a comment)? Otherwise it's a little bit obscure.

> +
>         of_property_for_each_string(np, "compatible", prop, compat) {
>                 parser = mtd_part_get_compatible_parser(compat);
>                 if (!parser)


Thanks,
Miquèl

On Sun, Feb 5, 2023 at 7:33 PM Saravana Kannan <saravanak@google.com> wrote:
>
> On Fri, Feb 3, 2023 at 1:39 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> >
> > пт, 3 февр. 2023 г. в 09:07, Saravana Kannan <saravanak@google.com>:
> > >
> > > On Thu, Feb 2, 2023 at 9:36 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> > > >
> > > > Hi Saravana,
> > > >
> > > > > Can you try the patch at the end of this email under these
> > > > > configurations and tell me which ones fail vs pass? I don't need logs
> > > >
> > > > I did these tests and here is the results:
> > >
> > > Did you hand edit the In-Reply-To: in the header? Because in the
> > > thread you are reply to the wrong email, but the context in your email
> > > seems to be from the right email.
> > >
> > > For example, see how your reply isn't under the email you are replying
> > > to in this thread overview:
> > > https://lore.kernel.org/lkml/20230127001141.407071-1-saravanak@google.com/#r
> > >
> > > > 1. On top of this series - Not works
> > > > 2. Without this series    - Works
> > > > 3. On top of the series with the fwnode_dev_initialized() deleted - Not works
> > > > 4. Without this series, with the fwnode_dev_initialized() deleted  - Works
> > > >
> > > > So your nvmem/core.c patch helps only when it is applied without the series.
> > > > But despite the fact that this helps to avoid getting stuck at probing
> > > > my ethernet device, there is still regression.
> > > >
> > > > When the ethernet module is loaded it takes a lot of time to drop dependency
> > > > from the nvmem-cell with mac address.
> > > >
> > > > Please look at the kernel logs below.
> > >
> > > The kernel logs below really aren't that useful for me in their
> > > current state. See more below.
> > >
> > > ---8<---- <snip> --->8----
> > >
> > > > P.S. Your nvmem patch definitely helps to avoid a device probe stuck
> > > > but look like it is not best way to solve a problem which we discussed
> > > > in the MTD thread.
> > > >
> > > > P.P.S. Also I don't know why your nvmem-cell patch doesn't help when it was
> > > > applied on top of this series. Maybe I missed something.
> > >
> > > Yeah, I'm not too sure if the test was done correctly. You also didn't
> > > answer my question about the dts from my earlier email.
> > > https://lore.kernel.org/lkml/CAGETcx8FpmbaRm2CCwqt3BRBpgbogwP5gNB+iA5OEtuxWVTNLA@mail.gmail.com/#t
> > >
> > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > drivers/core/base.c changed to the _info variants? And then share the
> > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > it doesn't get word wrapped by your email client. And please point me
> > > to the .dts that corresponds to your board. Without that, I can't
> > > debug much.
> > >
> > > Thanks,
> > > Saravana
> >
> > > Did you hand edit the In-Reply-To: in the header? Because in the
> > > thread you are reply to the wrong email, but the context in your email
> > > seems to be from the right email.
> >
> > Sorry for that, it seems like I accidently deleted it.
> >
> > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > drivers/core/base.c changed to the _info variants? And then share the
> > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > it doesn't get word wrapped by your email client. And please point me
> > > to the .dts that corresponds to your board. Without that, I can't
> > > debug much.
> >
> > Ok, I retested config 1 with all _debug logs changed to the _info. I
> > added the kernel log and the dts file to the attachment of this email.
>
> Ah, so your device is not supported/present upstream? Even though it's
> not upstream, I'll help fix this because it should fix what I believe
> are unreported issues in upstream.
>
> Ok I know why configs 1 - 4 behaved the way they did and why my test
> patch didn't help.
>
> After staring at mtd/nvmem code for a few hours I think mtd/nvmem
> interaction is kind of a mess. mtd core creates "partition" platform
> devices (including for nvmem-cells) that are probed by drivers in
> drivers/nvmem. However, there's no driver for "nvmem-cells" partition
> platform device. However, the nvmem core creates nvmem_device when
> nvmem_register() is called by MTD or these partition platform devices
> created by MTD. But these nvmem_devices are added to a nvmem_bus but
> the bus has no means to even register a driver (it should really be a
> nvmem_class and not nvmem_bus). And the nvmem_device sometimes points
> to the DT node of the MTD device or sometimes the partition platform
> devices or maybe no DT node at all.
>
> So it's a mess of multiple devices pointing to the same DT node with
> no clear way to identify which ones will point to a DT node and which
> ones will probe and which ones won't. In the future, we shouldn't
> allow adding new compatible strings for partitions for which we don't
> plan on adding nvmem drivers.

That won't work. Having a compatible string cannot mean there must be a driver.

Rob

On Mon, Feb 6, 2023 at 7:19 AM Rob Herring <robh+dt@kernel.org> wrote:
>
> On Sun, Feb 5, 2023 at 7:33 PM Saravana Kannan <saravanak@google.com> wrote:
> >
> > On Fri, Feb 3, 2023 at 1:39 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> > >
> > > пт, 3 февр. 2023 г. в 09:07, Saravana Kannan <saravanak@google.com>:
> > > >
> > > > On Thu, Feb 2, 2023 at 9:36 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> > > > >
> > > > > Hi Saravana,
> > > > >
> > > > > > Can you try the patch at the end of this email under these
> > > > > > configurations and tell me which ones fail vs pass? I don't need logs
> > > > >
> > > > > I did these tests and here is the results:
> > > >
> > > > Did you hand edit the In-Reply-To: in the header? Because in the
> > > > thread you are reply to the wrong email, but the context in your email
> > > > seems to be from the right email.
> > > >
> > > > For example, see how your reply isn't under the email you are replying
> > > > to in this thread overview:
> > > > https://lore.kernel.org/lkml/20230127001141.407071-1-saravanak@google.com/#r
> > > >
> > > > > 1. On top of this series - Not works
> > > > > 2. Without this series    - Works
> > > > > 3. On top of the series with the fwnode_dev_initialized() deleted - Not works
> > > > > 4. Without this series, with the fwnode_dev_initialized() deleted  - Works
> > > > >
> > > > > So your nvmem/core.c patch helps only when it is applied without the series.
> > > > > But despite the fact that this helps to avoid getting stuck at probing
> > > > > my ethernet device, there is still regression.
> > > > >
> > > > > When the ethernet module is loaded it takes a lot of time to drop dependency
> > > > > from the nvmem-cell with mac address.
> > > > >
> > > > > Please look at the kernel logs below.
> > > >
> > > > The kernel logs below really aren't that useful for me in their
> > > > current state. See more below.
> > > >
> > > > ---8<---- <snip> --->8----
> > > >
> > > > > P.S. Your nvmem patch definitely helps to avoid a device probe stuck
> > > > > but look like it is not best way to solve a problem which we discussed
> > > > > in the MTD thread.
> > > > >
> > > > > P.P.S. Also I don't know why your nvmem-cell patch doesn't help when it was
> > > > > applied on top of this series. Maybe I missed something.
> > > >
> > > > Yeah, I'm not too sure if the test was done correctly. You also didn't
> > > > answer my question about the dts from my earlier email.
> > > > https://lore.kernel.org/lkml/CAGETcx8FpmbaRm2CCwqt3BRBpgbogwP5gNB+iA5OEtuxWVTNLA@mail.gmail.com/#t
> > > >
> > > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > > drivers/core/base.c changed to the _info variants? And then share the
> > > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > > it doesn't get word wrapped by your email client. And please point me
> > > > to the .dts that corresponds to your board. Without that, I can't
> > > > debug much.
> > > >
> > > > Thanks,
> > > > Saravana
> > >
> > > > Did you hand edit the In-Reply-To: in the header? Because in the
> > > > thread you are reply to the wrong email, but the context in your email
> > > > seems to be from the right email.
> > >
> > > Sorry for that, it seems like I accidently deleted it.
> > >
> > > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > > drivers/core/base.c changed to the _info variants? And then share the
> > > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > > it doesn't get word wrapped by your email client. And please point me
> > > > to the .dts that corresponds to your board. Without that, I can't
> > > > debug much.
> > >
> > > Ok, I retested config 1 with all _debug logs changed to the _info. I
> > > added the kernel log and the dts file to the attachment of this email.
> >
> > Ah, so your device is not supported/present upstream? Even though it's
> > not upstream, I'll help fix this because it should fix what I believe
> > are unreported issues in upstream.
> >
> > Ok I know why configs 1 - 4 behaved the way they did and why my test
> > patch didn't help.
> >
> > After staring at mtd/nvmem code for a few hours I think mtd/nvmem
> > interaction is kind of a mess. mtd core creates "partition" platform
> > devices (including for nvmem-cells) that are probed by drivers in
> > drivers/nvmem. However, there's no driver for "nvmem-cells" partition
> > platform device. However, the nvmem core creates nvmem_device when
> > nvmem_register() is called by MTD or these partition platform devices
> > created by MTD. But these nvmem_devices are added to a nvmem_bus but
> > the bus has no means to even register a driver (it should really be a
> > nvmem_class and not nvmem_bus). And the nvmem_device sometimes points
> > to the DT node of the MTD device or sometimes the partition platform
> > devices or maybe no DT node at all.
> >
> > So it's a mess of multiple devices pointing to the same DT node with
> > no clear way to identify which ones will point to a DT node and which
> > ones will probe and which ones won't. In the future, we shouldn't
> > allow adding new compatible strings for partitions for which we don't
> > plan on adding nvmem drivers.
>
> That won't work. Having a compatible string cannot mean there must be a driver.

Right, I know what you mean Rob and I know where you are coming from
(DT isn't just about Linux or even driver core). But what I'm saying
is that this seems to already be the case for MTD partitions after
commit:
bcdf0315a61a mtd: call of_platform_populate() for MTD partitions

So, if we are adding compatible properties only for some of them, then
I'm saying we should make sure people write drivers for them going
forward.

I don't know enough about MTD partitions to know why only some of them
have compatible properties.

-Saravana

On Mon, Feb 6, 2023 at 1:39 AM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
>
> Hi Saravana,
>
> + Srinivas, nvmem maintainer
>
> saravanak@google.com wrote on Sun, 5 Feb 2023 17:32:57 -0800:
>
> > On Fri, Feb 3, 2023 at 1:39 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> > >
> > > пт, 3 февр. 2023 г. в 09:07, Saravana Kannan <saravanak@google.com>:
> > > >
> > > > On Thu, Feb 2, 2023 at 9:36 AM Maxim Kiselev <bigunclemax@gmail.com> wrote:
> > > > >
> > > > > Hi Saravana,
> > > > >
> > > > > > Can you try the patch at the end of this email under these
> > > > > > configurations and tell me which ones fail vs pass? I don't need logs
> > > > >
> > > > > I did these tests and here is the results:
> > > >
> > > > Did you hand edit the In-Reply-To: in the header? Because in the
> > > > thread you are reply to the wrong email, but the context in your email
> > > > seems to be from the right email.
> > > >
> > > > For example, see how your reply isn't under the email you are replying
> > > > to in this thread overview:
> > > > https://lore.kernel.org/lkml/20230127001141.407071-1-saravanak@google.com/#r
> > > >
> > > > > 1. On top of this series - Not works
> > > > > 2. Without this series    - Works
> > > > > 3. On top of the series with the fwnode_dev_initialized() deleted - Not works
> > > > > 4. Without this series, with the fwnode_dev_initialized() deleted  - Works
> > > > >
> > > > > So your nvmem/core.c patch helps only when it is applied without the series.
> > > > > But despite the fact that this helps to avoid getting stuck at probing
> > > > > my ethernet device, there is still regression.
> > > > >
> > > > > When the ethernet module is loaded it takes a lot of time to drop dependency
> > > > > from the nvmem-cell with mac address.
> > > > >
> > > > > Please look at the kernel logs below.
> > > >
> > > > The kernel logs below really aren't that useful for me in their
> > > > current state. See more below.
> > > >
> > > > ---8<---- <snip> --->8----
> > > >
> > > > > P.S. Your nvmem patch definitely helps to avoid a device probe stuck
> > > > > but look like it is not best way to solve a problem which we discussed
> > > > > in the MTD thread.
> > > > >
> > > > > P.P.S. Also I don't know why your nvmem-cell patch doesn't help when it was
> > > > > applied on top of this series. Maybe I missed something.
> > > >
> > > > Yeah, I'm not too sure if the test was done correctly. You also didn't
> > > > answer my question about the dts from my earlier email.
> > > > https://lore.kernel.org/lkml/CAGETcx8FpmbaRm2CCwqt3BRBpgbogwP5gNB+iA5OEtuxWVTNLA@mail.gmail.com/#t
> > > >
> > > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > > drivers/core/base.c changed to the _info variants? And then share the
> > > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > > it doesn't get word wrapped by your email client. And please point me
> > > > to the .dts that corresponds to your board. Without that, I can't
> > > > debug much.
> > > >
> > > > Thanks,
> > > > Saravana
> > >
> > > > Did you hand edit the In-Reply-To: in the header? Because in the
> > > > thread you are reply to the wrong email, but the context in your email
> > > > seems to be from the right email.
> > >
> > > Sorry for that, it seems like I accidently deleted it.
> > >
> > > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > > drivers/core/base.c changed to the _info variants? And then share the
> > > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > > it doesn't get word wrapped by your email client. And please point me
> > > > to the .dts that corresponds to your board. Without that, I can't
> > > > debug much.
> > >
> > > Ok, I retested config 1 with all _debug logs changed to the _info. I
> > > added the kernel log and the dts file to the attachment of this email.
> >
> > Ah, so your device is not supported/present upstream? Even though it's
> > not upstream, I'll help fix this because it should fix what I believe
> > are unreported issues in upstream.
> >
> > Ok I know why configs 1 - 4 behaved the way they did and why my test
> > patch didn't help.
> >
> > After staring at mtd/nvmem code for a few hours I think mtd/nvmem
> > interaction is kind of a mess.
>
> nvmem is a recent subsystem but mtd carries a lot of legacy stuff we
> cannot really re-wire without breaking users, so nvmem on top of mtd
> of course inherit from the fragile designs in place.

Thanks for the context. Yeah, I figured. That's why I explicitly
limited my comment to "interaction". Although, I'd love to see the MTD
parsers all be converted to proper drivers that probe. MTD is
essentially repeating the driver matching logic. I think it can be
cleaned up to move to proper drivers and still not break backward
compatibility. Not saying it'll be trivial, but it should be possible.
Ironically MTD uses mtd_class but has real drivers that work on the
device (compared to nvmem_bus below).

> > mtd core creates "partition" platform
> > devices (including for nvmem-cells) that are probed by drivers in
> > drivers/nvmem. However, there's no driver for "nvmem-cells" partition
> > platform device. However, the nvmem core creates nvmem_device when
> > nvmem_register() is called by MTD or these partition platform devices
> > created by MTD. But these nvmem_devices are added to a nvmem_bus but
> > the bus has no means to even register a driver (it should really be a
> > nvmem_class and not nvmem_bus).
>
> Srinivas, do you think we could change this?

Yeah, this part gets a bit tricky. It depends on whether the sysfs
files for nvmem devices is considered an ABI. Changing from bus to
class would change the sysfs path for nvmem devices from:
/sys/class/nvmem to /sys/bus/nvmem

> > And the nvmem_device sometimes points
> > to the DT node of the MTD device or sometimes the partition platform
> > devices or maybe no DT node at all.
>
> I guess this comes from the fact that this is not strongly defined in
> mtd and depends on the situation (not mentioning 20 years of history
> there as well). "mtd" is a bit inconsistent on what it means. Older
> designs mixed: controllers, ECC engines when relevant and memories;
> while these three components are completely separated. Hence
> sometimes the mtd device ends up being the top level controller,
> sometimes it's just one partition...
>
> But I'm surprised not all of them point to a DT node. Could you show us
> an example? Because that might likely be unexpected (or perhaps I am
> missing something).

Well, the logic that sets the DT node for nvmem_device is like so:

        if (config->of_node)
                nvmem->dev.of_node = config->of_node;
        else if (!config->no_of_node)
                nvmem->dev.of_node = config->dev->of_node;

So there's definitely a path (where both if's could be false) where
the DT node will not get set. I don't know if that path is possible
with the existing users of nvmem_register(), but it's definitely
possible.

> > So it's a mess of multiple devices pointing to the same DT node with
> > no clear way to identify which ones will point to a DT node and which
> > ones will probe and which ones won't. In the future, we shouldn't
> > allow adding new compatible strings for partitions for which we don't
> > plan on adding nvmem drivers.
> >
> > Can you give the patch at the end of the email a shot? It should fix
> > the issue with this series and without this series. It just avoids
> > this whole mess by not creating useless platform device for
> > nvmem-cells compatible DT nodes.
>
> Thanks a lot for your help.

No problem. I want fw_devlink to work for everyone.

> >
> > Thanks,
> > Saravana
> >
> > diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> > index d442fa94c872..88a213f4d651 100644
> > --- a/drivers/mtd/mtdpart.c
> > +++ b/drivers/mtd/mtdpart.c
> > @@ -577,6 +577,7 @@ static int mtd_part_of_parse(struct mtd_info *master,
> >  {
> >         struct mtd_part_parser *parser;
> >         struct device_node *np;
> > +       struct device_node *child;
> >         struct property *prop;
> >         struct device *dev;
> >         const char *compat;
> > @@ -594,6 +595,10 @@ static int mtd_part_of_parse(struct mtd_info *master,
> >         else
> >                 np = of_get_child_by_name(np, "partitions");
> >
> > +       for_each_child_of_node(np, child)
> > +               if (of_device_is_compatible(child, "nvmem-cells"))
> > +                       of_node_set_flag(child, OF_POPULATED);
>
> What about a comment explaining why we need that in the final patch
> (with a comment)? Otherwise it's a little bit obscure.

This wasn't meant to be reviewed :) Just a quick patch to make sure
I'm going down the right path. Once Maxim confirms I was going to roll
this into a proper patch.

But point noted. Will add a comment.

Thanks,
Saravana

Hi Saravana,

> > > > > So, can you please retest config 1 with all pr_debug and dev_dbg in
> > > > > drivers/core/base.c changed to the _info variants? And then share the
> > > > > kernel log from the beginning of boot? Maybe attach it to the email so
> > > > > it doesn't get word wrapped by your email client. And please point me
> > > > > to the .dts that corresponds to your board. Without that, I can't
> > > > > debug much.  
> > > >
> > > > Ok, I retested config 1 with all _debug logs changed to the _info. I
> > > > added the kernel log and the dts file to the attachment of this email.  
> > >
> > > Ah, so your device is not supported/present upstream? Even though it's
> > > not upstream, I'll help fix this because it should fix what I believe
> > > are unreported issues in upstream.
> > >
> > > Ok I know why configs 1 - 4 behaved the way they did and why my test
> > > patch didn't help.
> > >
> > > After staring at mtd/nvmem code for a few hours I think mtd/nvmem
> > > interaction is kind of a mess.  
> >
> > nvmem is a recent subsystem but mtd carries a lot of legacy stuff we
> > cannot really re-wire without breaking users, so nvmem on top of mtd
> > of course inherit from the fragile designs in place.  
> 
> Thanks for the context. Yeah, I figured. That's why I explicitly
> limited my comment to "interaction". Although, I'd love to see the MTD
> parsers all be converted to proper drivers that probe. MTD is
> essentially repeating the driver matching logic. I think it can be
> cleaned up to move to proper drivers and still not break backward
> compatibility. Not saying it'll be trivial, but it should be possible.
> Ironically MTD uses mtd_class but has real drivers that work on the
> device (compared to nvmem_bus below).
> 
> > > mtd core creates "partition" platform
> > > devices (including for nvmem-cells) that are probed by drivers in
> > > drivers/nvmem. However, there's no driver for "nvmem-cells" partition
> > > platform device. However, the nvmem core creates nvmem_device when
> > > nvmem_register() is called by MTD or these partition platform devices
> > > created by MTD. But these nvmem_devices are added to a nvmem_bus but
> > > the bus has no means to even register a driver (it should really be a
> > > nvmem_class and not nvmem_bus).  
> >
> > Srinivas, do you think we could change this?  
> 
> Yeah, this part gets a bit tricky. It depends on whether the sysfs
> files for nvmem devices is considered an ABI. Changing from bus to
> class would change the sysfs path for nvmem devices from:
> /sys/class/nvmem to /sys/bus/nvmem

Ok, so this is a no :)

> > > And the nvmem_device sometimes points
> > > to the DT node of the MTD device or sometimes the partition platform
> > > devices or maybe no DT node at all.  
> >
> > I guess this comes from the fact that this is not strongly defined in
> > mtd and depends on the situation (not mentioning 20 years of history
> > there as well). "mtd" is a bit inconsistent on what it means. Older
> > designs mixed: controllers, ECC engines when relevant and memories;
> > while these three components are completely separated. Hence
> > sometimes the mtd device ends up being the top level controller,
> > sometimes it's just one partition...
> >
> > But I'm surprised not all of them point to a DT node. Could you show us
> > an example? Because that might likely be unexpected (or perhaps I am
> > missing something).  
> 
> Well, the logic that sets the DT node for nvmem_device is like so:
> 
>         if (config->of_node)
>                 nvmem->dev.of_node = config->of_node;
>         else if (!config->no_of_node)
>                 nvmem->dev.of_node = config->dev->of_node;
> 
> So there's definitely a path (where both if's could be false) where
> the DT node will not get set. I don't know if that path is possible
> with the existing users of nvmem_register(), but it's definitely
> possible.

It's an actual path. I just checked more in details, this is the change
from 2018 which uses the no_of_node flag:
c4dfa25ab307 ("mtd: add support for reading MTD devices via the nvmem API")

It basically allows any mtd device to be accessible (read-only) through
nvmem. So mtd partitions or such which are not described in the DT may
just be accessed through nvmem (that is my current understanding).

There was later a patch in 2021 which prevented this flag to be
automatically set, so that if partitions (well, mtd devices in general)
were described in the DT, they would provide a valid of_node in order
to be used as cell providers (again, my understanding):
658c4448bbbf ("mtd: core: add nvmem-cells compatible to parse mtd as nvmem cells")

But I guess the major problem comes from the nvmem-cell compatible. I
am wondering if it would make sense to kind of transpose the meaning of
this compatible into a property. But, well, backward compatibility
would still be a problem I guess...

> > > So it's a mess of multiple devices pointing to the same DT node with
> > > no clear way to identify which ones will point to a DT node and which
> > > ones will probe and which ones won't. In the future, we shouldn't
> > > allow adding new compatible strings for partitions for which we don't
> > > plan on adding nvmem drivers.
> > >
> > > Can you give the patch at the end of the email a shot? It should fix
> > > the issue with this series and without this series. It just avoids
> > > this whole mess by not creating useless platform device for
> > > nvmem-cells compatible DT nodes.  
> >
> > Thanks a lot for your help.  
> 
> No problem. I want fw_devlink to work for everyone.
> 

Thanks,
Miquèl