| Message ID | 20210621103310.186334-1-jhp@endlessos.org |
|---|---|
| State | New |
| Headers | show |
| Series | net: bcmgenet: Fix attaching to PYH failed on RPi 4B | expand |
Florian Fainelli <f.fainelli@gmail.com> 於 2021年6月22日 週二 上午5:47寫道： > > On 6/21/21 1:15 PM, Stefan Wahren wrote: > > Am 21.06.21 um 18:56 schrieb Peter Robinson: > >> On Mon, Jun 21, 2021 at 5:39 PM Florian Fainelli <f.fainelli@gmail.com> wrote: > >>> On 6/21/21 6:09 AM, Andrew Lunn wrote: > >>>> On Mon, Jun 21, 2021 at 06:33:11PM +0800, Jian-Hong Pan wrote: > >>>>> The Broadcom UniMAC MDIO bus comes too late. So, GENET cannot find the > >>>>> ethernet PHY on UniMAC MDIO bus. This leads GENET fail to attach the > >>>>> PHY. > >>>>> > >>>>> bcmgenet fd580000.ethernet: GENET 5.0 EPHY: 0x0000 > >>>>> ... > >>>>> could not attach to PHY > >>>>> bcmgenet fd580000.ethernet eth0: failed to connect to PHY > >>>>> uart-pl011 fe201000.serial: no DMA platform data > >>>>> libphy: bcmgenet MII bus: probed > >>>>> ... > >>>>> unimac-mdio unimac-mdio.-19: Broadcom UniMAC MDIO bus > >>>>> > >>>>> This patch makes GENET try to connect the PHY up to 3 times. Also, waits > >>>>> a while between each time for mdio-bcm-unimac module's loading and > >>>>> probing. > >>>> Don't loop. Return -EPROBE_DEFER. The driver core will then probed the > >>>> driver again later, by which time, the MDIO bus driver should of > >>>> probed. > >>> This is unlikely to work because GENET register the mdio-bcm-unimac > >>> platform device so we will likely run into a chicken and egg problem, > >>> though surprisingly I have not seen this on STB platforms where GENET is > >>> used, I will try building everything as a module like you do. Can you > >>> see if the following helps: > >> For reference we have mdio_bcm_unimac/genet both built as modules in > >> Fedora and I've not seen this issue reported using vanilla upstream > >> kernels if that's a useful reference point. > > > > I was also unable to reproduce this issue, but it seems to be a known > > issue [1], [2]. > > > > Jian-Hong opened an issue in my Github repo [3], but before the issue > > was narrowed down, he decided to send this workaround. > > The comment about changing the phy-mode property is not quite making > sense to me, except if that means that in one case the Broadcom PHY > driver is used and in the other case the Generic PHY driver is used. > > What is not clear to me from the debugging that has been done so far is > whether the mdio-bcm-unimac MDIO controller was not loaded at the time > of_phy_connect() was trying to identify the PHY device. MODULE_SOFTDEP("pre: mdio-bcm-unimac") mentioned in the comment [1] solves this issue. Tracing the code by following the debug message in comment #2 [2], I learned the path bcmgenet_mii_probe()'s of_phy_connect() -> of_phy_find_device() -> of_mdio_find_device() -> bus_find_device_by_of_node(). And, bus_find_device_by_of_node() cannot find the device on the mdio bus. So, I traced bcm2711-rpi-4-b's device tree to find out which one is the mdio device and why it has not been prepared ready on the mdio bus for genet. Then, I found out it is mdio-bcm-unimac module as mentioned in comment #4 [3]. Also, noticed "unimac-mdio unimac-mdio.-19: Broadcom UniMAC MDIO bus" comes after "bcmgenet fd580000.ethernet eth0: failed to connect to PHY" in the log. With these findings, I try to re-modprobe genet module again. The ethernet on RPi 4B works correctly! Also, noticed mdio-bcm-unimac module is loaded before I re-modprobe genet module. Therefore, I try to make mdio-bcm-unimac built in kernel image, instead of a module. Then, genet always can find the mdio device on the bus and the ethernet works as well. Consequently, the idea, loading mdio-bcm-unimac module earlier than genet module comes in my head! However, I don't know the key word "MODULE_SOFTDEP" until Florian's guide. That is why I have a loop to connect the PHY in the original patch. But, I understand MODULE_SOFTDEP is a better solution now! I think this is like the module loading order situation mentioned in commit 11287b693d03 ("r8169: load Realtek PHY driver module before r8169") [4]. [1] https://bugzilla.kernel.org/show_bug.cgi?id=213485#c6 [2] https://bugzilla.kernel.org/show_bug.cgi?id=213485#c2 [3] https://bugzilla.kernel.org/show_bug.cgi?id=213485#c4 [4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=11287b693d03830010356339e4ceddf47dee34fa Jian-Hong Pan
On 22.06.2021 08:29, Jian-Hong Pan wrote: > Florian Fainelli <f.fainelli@gmail.com> 於 2021年6月22日 週二 上午5:47寫道： >> >> On 6/21/21 1:15 PM, Stefan Wahren wrote: >>> Am 21.06.21 um 18:56 schrieb Peter Robinson: >>>> On Mon, Jun 21, 2021 at 5:39 PM Florian Fainelli <f.fainelli@gmail.com> wrote: >>>>> On 6/21/21 6:09 AM, Andrew Lunn wrote: >>>>>> On Mon, Jun 21, 2021 at 06:33:11PM +0800, Jian-Hong Pan wrote: >>>>>>> The Broadcom UniMAC MDIO bus comes too late. So, GENET cannot find the >>>>>>> ethernet PHY on UniMAC MDIO bus. This leads GENET fail to attach the >>>>>>> PHY. >>>>>>> >>>>>>> bcmgenet fd580000.ethernet: GENET 5.0 EPHY: 0x0000 >>>>>>> ... >>>>>>> could not attach to PHY >>>>>>> bcmgenet fd580000.ethernet eth0: failed to connect to PHY >>>>>>> uart-pl011 fe201000.serial: no DMA platform data >>>>>>> libphy: bcmgenet MII bus: probed >>>>>>> ... >>>>>>> unimac-mdio unimac-mdio.-19: Broadcom UniMAC MDIO bus >>>>>>> >>>>>>> This patch makes GENET try to connect the PHY up to 3 times. Also, waits >>>>>>> a while between each time for mdio-bcm-unimac module's loading and >>>>>>> probing. >>>>>> Don't loop. Return -EPROBE_DEFER. The driver core will then probed the >>>>>> driver again later, by which time, the MDIO bus driver should of >>>>>> probed. >>>>> This is unlikely to work because GENET register the mdio-bcm-unimac >>>>> platform device so we will likely run into a chicken and egg problem, >>>>> though surprisingly I have not seen this on STB platforms where GENET is >>>>> used, I will try building everything as a module like you do. Can you >>>>> see if the following helps: >>>> For reference we have mdio_bcm_unimac/genet both built as modules in >>>> Fedora and I've not seen this issue reported using vanilla upstream >>>> kernels if that's a useful reference point. >>> >>> I was also unable to reproduce this issue, but it seems to be a known >>> issue [1], [2]. >>> >>> Jian-Hong opened an issue in my Github repo [3], but before the issue >>> was narrowed down, he decided to send this workaround. >> >> The comment about changing the phy-mode property is not quite making >> sense to me, except if that means that in one case the Broadcom PHY >> driver is used and in the other case the Generic PHY driver is used. >> >> What is not clear to me from the debugging that has been done so far is >> whether the mdio-bcm-unimac MDIO controller was not loaded at the time >> of_phy_connect() was trying to identify the PHY device. > > MODULE_SOFTDEP("pre: mdio-bcm-unimac") mentioned in the comment [1] > solves this issue. > > Tracing the code by following the debug message in comment #2 [2], I > learned the path bcmgenet_mii_probe()'s of_phy_connect() -> > of_phy_find_device() -> of_mdio_find_device() -> > bus_find_device_by_of_node(). And, bus_find_device_by_of_node() > cannot find the device on the mdio bus. > > So, I traced bcm2711-rpi-4-b's device tree to find out which one is > the mdio device and why it has not been prepared ready on the mdio bus > for genet. > Then, I found out it is mdio-bcm-unimac module as mentioned in comment > #4 [3]. Also, noticed "unimac-mdio unimac-mdio.-19: Broadcom UniMAC > MDIO bus" comes after "bcmgenet fd580000.ethernet eth0: failed to > connect to PHY" in the log. > > With these findings, I try to re-modprobe genet module again. The > ethernet on RPi 4B works correctly! Also, noticed mdio-bcm-unimac > module is loaded before I re-modprobe genet module. > Therefore, I try to make mdio-bcm-unimac built in kernel image, > instead of a module. Then, genet always can find the mdio device on > the bus and the ethernet works as well. > > Consequently, the idea, loading mdio-bcm-unimac module earlier than > genet module comes in my head! However, I don't know the key word > "MODULE_SOFTDEP" until Florian's guide. That is why I have a loop to > connect the PHY in the original patch. But, I understand > MODULE_SOFTDEP is a better solution now! > > I think this is like the module loading order situation mentioned in > commit 11287b693d03 ("r8169: load Realtek PHY driver module before > r8169") [4]. > The reason in r8169 is different. When people add r8169 module to initramfs but not the Realtek PHY driver module then loading r8169 will fail. The MODULE_SOFTDEP is a hint to tools building initramfs. > [1] https://bugzilla.kernel.org/show_bug.cgi?id=213485#c6 > [2] https://bugzilla.kernel.org/show_bug.cgi?id=213485#c2 > [3] https://bugzilla.kernel.org/show_bug.cgi?id=213485#c4 > [4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=11287b693d03830010356339e4ceddf47dee34fa > > Jian-Hong Pan >
Heiner Kallweit <hkallweit1@gmail.com> 於 2021年6月22日 週二 下午2:50寫道： > > On 22.06.2021 08:29, Jian-Hong Pan wrote: > > Florian Fainelli <f.fainelli@gmail.com> 於 2021年6月22日 週二 上午5:47寫道： > >> > >> On 6/21/21 1:15 PM, Stefan Wahren wrote: > >>> Am 21.06.21 um 18:56 schrieb Peter Robinson: > >>>> On Mon, Jun 21, 2021 at 5:39 PM Florian Fainelli <f.fainelli@gmail.com> wrote: > >>>>> On 6/21/21 6:09 AM, Andrew Lunn wrote: > >>>>>> On Mon, Jun 21, 2021 at 06:33:11PM +0800, Jian-Hong Pan wrote: > >>>>>>> The Broadcom UniMAC MDIO bus comes too late. So, GENET cannot find the > >>>>>>> ethernet PHY on UniMAC MDIO bus. This leads GENET fail to attach the > >>>>>>> PHY. > >>>>>>> > >>>>>>> bcmgenet fd580000.ethernet: GENET 5.0 EPHY: 0x0000 > >>>>>>> ... > >>>>>>> could not attach to PHY > >>>>>>> bcmgenet fd580000.ethernet eth0: failed to connect to PHY > >>>>>>> uart-pl011 fe201000.serial: no DMA platform data > >>>>>>> libphy: bcmgenet MII bus: probed > >>>>>>> ... > >>>>>>> unimac-mdio unimac-mdio.-19: Broadcom UniMAC MDIO bus > >>>>>>> > >>>>>>> This patch makes GENET try to connect the PHY up to 3 times. Also, waits > >>>>>>> a while between each time for mdio-bcm-unimac module's loading and > >>>>>>> probing. > >>>>>> Don't loop. Return -EPROBE_DEFER. The driver core will then probed the > >>>>>> driver again later, by which time, the MDIO bus driver should of > >>>>>> probed. > >>>>> This is unlikely to work because GENET register the mdio-bcm-unimac > >>>>> platform device so we will likely run into a chicken and egg problem, > >>>>> though surprisingly I have not seen this on STB platforms where GENET is > >>>>> used, I will try building everything as a module like you do. Can you > >>>>> see if the following helps: > >>>> For reference we have mdio_bcm_unimac/genet both built as modules in > >>>> Fedora and I've not seen this issue reported using vanilla upstream > >>>> kernels if that's a useful reference point. > >>> > >>> I was also unable to reproduce this issue, but it seems to be a known > >>> issue [1], [2]. > >>> > >>> Jian-Hong opened an issue in my Github repo [3], but before the issue > >>> was narrowed down, he decided to send this workaround. > >> > >> The comment about changing the phy-mode property is not quite making > >> sense to me, except if that means that in one case the Broadcom PHY > >> driver is used and in the other case the Generic PHY driver is used. > >> > >> What is not clear to me from the debugging that has been done so far is > >> whether the mdio-bcm-unimac MDIO controller was not loaded at the time > >> of_phy_connect() was trying to identify the PHY device. > > > > MODULE_SOFTDEP("pre: mdio-bcm-unimac") mentioned in the comment [1] > > solves this issue. > > > > Tracing the code by following the debug message in comment #2 [2], I > > learned the path bcmgenet_mii_probe()'s of_phy_connect() -> > > of_phy_find_device() -> of_mdio_find_device() -> > > bus_find_device_by_of_node(). And, bus_find_device_by_of_node() > > cannot find the device on the mdio bus. > > > > So, I traced bcm2711-rpi-4-b's device tree to find out which one is > > the mdio device and why it has not been prepared ready on the mdio bus > > for genet. > > Then, I found out it is mdio-bcm-unimac module as mentioned in comment > > #4 [3]. Also, noticed "unimac-mdio unimac-mdio.-19: Broadcom UniMAC > > MDIO bus" comes after "bcmgenet fd580000.ethernet eth0: failed to > > connect to PHY" in the log. > > > > With these findings, I try to re-modprobe genet module again. The > > ethernet on RPi 4B works correctly! Also, noticed mdio-bcm-unimac > > module is loaded before I re-modprobe genet module. > > Therefore, I try to make mdio-bcm-unimac built in kernel image, > > instead of a module. Then, genet always can find the mdio device on > > the bus and the ethernet works as well. > > > > Consequently, the idea, loading mdio-bcm-unimac module earlier than > > genet module comes in my head! However, I don't know the key word > > "MODULE_SOFTDEP" until Florian's guide. That is why I have a loop to > > connect the PHY in the original patch. But, I understand > > MODULE_SOFTDEP is a better solution now! Forgot to place some reference as note: * MODULE_SOFTDEP is defined in include/linux/module.h [1] * modprobe.d has an example: [2] Assume "softdep c pre: a b post: d e" is provided in the configuration. Running "modprobe c" is now equivalent to "modprobe a b c d e" without the softdep. [1] https://elixir.bootlin.com/linux/v5.13-rc7/source/include/linux/module.h#L170 [2] https://man7.org/linux/man-pages/man5/modprobe.d.5.html > > I think this is like the module loading order situation mentioned in > > commit 11287b693d03 ("r8169: load Realtek PHY driver module before > > r8169") [4]. > > > The reason in r8169 is different. When people add r8169 module to > initramfs but not the Realtek PHY driver module then loading > r8169 will fail. The MODULE_SOFTDEP is a hint to tools building > initramfs. Thanks for Heiner's quick clarification. Maybe I missed some background of the commit ("r8169: load Realtek PHY driver module before r8169"). Jian-Hong Pan > > [1] https://bugzilla.kernel.org/show_bug.cgi?id=213485#c6 > > [2] https://bugzilla.kernel.org/show_bug.cgi?id=213485#c2 > > [3] https://bugzilla.kernel.org/show_bug.cgi?id=213485#c4 > > [4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=11287b693d03830010356339e4ceddf47dee34fa > > > > Jian-Hong Pan > > >
diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c index 5335244e4577..64f244471fd3 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmmii.c +++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c @@ -289,6 +289,7 @@ int bcmgenet_mii_probe(struct net_device *dev) struct phy_device *phydev; u32 phy_flags = 0; int ret; + int i; /* Communicate the integrated PHY revision */ if (priv->internal_phy) @@ -301,8 +302,22 @@ int bcmgenet_mii_probe(struct net_device *dev) priv->old_pause = -1; if (dn) { - phydev = of_phy_connect(dev, priv->phy_dn, bcmgenet_mii_setup, - phy_flags, priv->phy_interface); + /* Try to connect the PHY on UniMAC DMIO bus up to 3 times. + * Wait a while between each time for mdio-bcm-unimac module's + * loading and probing. + */ + phydev = NULL; + for (i = 1; i < 4 && !phydev; i++) { + netdev_info(dev, + "connect %s on UniMAC MDIO bus %d time", + priv->phy_dn->full_name, i); + phydev = of_phy_connect(dev, priv->phy_dn, + bcmgenet_mii_setup, + phy_flags, priv->phy_interface); + if (!phydev && i < 3) + msleep(500); + } + if (!phydev) { pr_err("could not attach to PHY\n"); return -ENODEV;
The Broadcom UniMAC MDIO bus comes too late. So, GENET cannot find the ethernet PHY on UniMAC MDIO bus. This leads GENET fail to attach the PHY. bcmgenet fd580000.ethernet: GENET 5.0 EPHY: 0x0000 ... could not attach to PHY bcmgenet fd580000.ethernet eth0: failed to connect to PHY uart-pl011 fe201000.serial: no DMA platform data libphy: bcmgenet MII bus: probed ... unimac-mdio unimac-mdio.-19: Broadcom UniMAC MDIO bus This patch makes GENET try to connect the PHY up to 3 times. Also, waits a while between each time for mdio-bcm-unimac module's loading and probing. Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=213485 Signed-off-by: Jian-Hong Pan <jhp@endlessos.org> --- drivers/net/ethernet/broadcom/genet/bcmmii.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-)