| Message ID | 20220509233235.995021-1-dmitry.osipenko@collabora.com |
|---|---|
| Headers | show |
| Series | Introduce power-off+restart call chain API | expand |
On Tue, May 10, 2022 at 1:33 AM Dmitry Osipenko <dmitry.osipenko@collabora.com> wrote: > > Problem > ------- > > SoC devices require power-off call chaining functionality from kernel. > We have a widely used restart chaining provided by restart notifier API, > but nothing for power-off. > > Solution > -------- > > Introduce new API that provides call chains support for all restart and > power-off modes. The new API is designed with simplicity and extensibility > in mind. > > This is a third attempt to introduce the new API. First was made by > Guenter Roeck back in 2014, second was made by Thierry Reding in 2017. > In fact the work didn't stop and recently arm_pm_restart() was removed > from v5.14 kernel, which was a part of preparatory work started by > Guenter Roeck. > > Adoption plan > ------------- > > This patchset introduces the new API. It also converts multiple drivers > and arch code to the new API to demonstrate how it all looks in practice, > removing the pm_power_off_prepare global variable. > > The plan is: > > 1. Merge the new API and convert arch code to use do_kernel_power_off(). > For now the new API will co-exist with the older API. > > 2. Convert all drivers and platform code to the new API. > > 3. Remove obsoleted pm_power_off and pm_power_off_prepare variables. > > Results > ------- > > 1. Devices can be powered off properly. > > 2. Global variables are removed from drivers. > > 3. Global pm_power_off and pm_power_off_prepare callback variables are > removed once all users are converted to the new API. The latter callback > is removed by patch #24 of this series. > > 4. Ambiguous call chain ordering is prohibited for non-default priorities. > > Changelog: > > v8: - Reworked sys-off handler like was suggested by Rafael Wysocki in > the comments to v7. > > - The struct sys-off handler now is private to kernel/reboot.c and > new API is simplified. > > - There is a single sys-off API function for all handler types. > Users shall pass the required sys-off mode type (restart, power-off > and etc). > > - There is single struct sys_off_data callback argument for all > handler modes. > > - User's callback now must return NOTIFY_DONE or NOTIFY_STOP. > > - The default priority level is zero now. > > - Multiple handlers now allowed to be registered at the default > priority level. > > - Power-off call chain is atomic now, like the restart chain. > > - kernel/reboot.c changes are split up into several logical patches. > > - Added r-b from Michał Mirosław to unmodified patches from v7. > > - Added acks that were missing in v7 by accident. The v8 looks much better than the previous versions to me. I actually don't really have any comments on it except for the minor remark regarding patch [1/27] sent separately. Please just send an update of that one patch and I will queue up the series for 5.19. However, I'm going to send a pull request with it in the second half of the merge window, after the majority of the other changes in the subsystems touched by it have been integrated. > v7: - Rebased on a recent linux-next. Dropped the recently removed > NDS32 architecture. Only SH and x86 arches left un-acked. > > - Added acks from Thomas Bogendoerfer and Krzysztof Kozlowski > to the MIPS and memory/emif patches respectively. > > - Made couple minor cosmetic improvements to the new API. > > - A month ago I joined Collabora and continuing to work on this series > on the company's time, so changed my email address to collabora.com > > v6: - Rebased on a recent linux-next. > > - Made minor couple cosmetic changes. > > v5: - Dropped patches which cleaned up notifier/reboot headers, as was > requested by Rafael Wysocki. > > - Dropped WARN_ON() from the code, as was requested by Rafael Wysocki. > Replaced it with pr_err() appropriately. > > - Dropped *_notifier_has_unique_priority() functions and added > *_notifier_chain_register_unique_prio() instead, as was suggested > by Michał Mirosław and Rafael Wysocki. > > - Dropped export of blocking_notifier_call_chain_is_empty() symbol, > as was suggested by Rafael Wysocki. > > - Michał Mirosław suggested that will be better to split up patch > that adds the new API to ease reviewing, but Rafael Wysocki asked > not add more patches, so I kept it as a single patch. > > - Added temporary "weak" stub for pm_power_off() which fixes linkage > failure once symbol is removed from arch/* code. Previously I missed > this problem because was only compile-testing object files. > > v4: - Made a very minor improvement to doc comments, clarifying couple > default values. > > - Corrected list of emails recipient by adding Linus, Sebastian, > Philipp and more NDS people. Removed bouncing emails. > > - Added acks that were given to v3. > > v3: - Renamed power_handler to sys_off_handler as was suggested by > Rafael Wysocki. > > - Improved doc-comments as was suggested by Rafael Wysocki. Added more > doc-comments. > > - Implemented full set of 180 patches which convert whole kernel in > accordance to the plan, see link [1] above. Slightly adjusted API to > better suit for the remaining converted drivers. > > * Added unregister_sys_off_handler() that is handy for a couple old > platform drivers. > > * Dropped devm_register_trivial_restart_handler(), 'simple' variant > is enough to have. > > - Improved "Add atomic/blocking_notifier_has_unique_priority()" patch, > as was suggested by Andy Shevchenko. Also replaced down_write() with > down_read() and factored out common notifier_has_unique_priority(). > > - Added stop_chain field to struct restart_data and reboot_prep_data > after discovering couple drivers wanting that feature. > > - Added acks that were given to v2. > > v2: - Replaced standalone power-off call chain demo-API with the combined > power-off+restart API because this is what drivers want. It's a more > comprehensive solution. > > - Converted multiple drivers and arch code to the new API. Suggested by > Andy Shevchenko. I skimmed through the rest of drivers, verifying that > new API suits them. The rest of the drivers will be converted once we > will settle on the new API, otherwise will be too many patches here. > > - v2 API doesn't expose notifier to users and require handlers to > have unique priority. Suggested by Guenter Roeck. > > - v2 API has power-off chaining disabled by default and require > drivers to explicitly opt-in to the chaining. This preserves old > behaviour for existing drivers once they are converted to the new > API. > > Dmitry Osipenko (27): > notifier: Add atomic_notifier_call_chain_is_empty() > notifier: Add blocking/atomic_notifier_chain_register_unique_prio() > kernel/reboot: Introduce sys-off handler API > kernel/reboot: Wrap legacy power-off callbacks into sys-off handlers > kernel/reboot: Add do_kernel_power_off() > kernel/reboot: Add stub for pm_power_off > kernel/reboot: Add kernel_can_power_off() > kernel/reboot: Add register_platform_power_off() > ARM: Use do_kernel_power_off() > csky: Use do_kernel_power_off() > riscv: Use do_kernel_power_off() > arm64: Use do_kernel_power_off() > parisc: Use do_kernel_power_off() > xen/x86: Use do_kernel_power_off() > powerpc: Use do_kernel_power_off() > m68k: Switch to new sys-off handler API > sh: Use do_kernel_power_off() > x86: Use do_kernel_power_off() > ia64: Use do_kernel_power_off() > mips: Use do_kernel_power_off() > memory: emif: Use kernel_can_power_off() > ACPI: power: Switch to sys-off handler API > regulator: pfuze100: Use devm_register_sys_off_handler() > reboot: Remove pm_power_off_prepare() > soc/tegra: pmc: Use sys-off handler API to power off Nexus 7 properly > kernel/reboot: Add devm_register_power_off_handler() > kernel/reboot: Add devm_register_restart_handler() > > arch/arm/kernel/reboot.c | 4 +- > arch/arm64/kernel/process.c | 3 +- > arch/csky/kernel/power.c | 6 +- > arch/ia64/kernel/process.c | 4 +- > arch/m68k/emu/natfeat.c | 3 +- > arch/m68k/include/asm/machdep.h | 1 - > arch/m68k/kernel/process.c | 5 +- > arch/m68k/kernel/setup_mm.c | 1 - > arch/m68k/kernel/setup_no.c | 1 - > arch/m68k/mac/config.c | 4 +- > arch/mips/kernel/reset.c | 3 +- > arch/parisc/kernel/process.c | 4 +- > arch/powerpc/kernel/setup-common.c | 4 +- > arch/powerpc/xmon/xmon.c | 3 +- > arch/riscv/kernel/reset.c | 12 +- > arch/sh/kernel/reboot.c | 3 +- > arch/x86/kernel/reboot.c | 4 +- > arch/x86/xen/enlighten_pv.c | 4 +- > drivers/acpi/sleep.c | 16 +- > drivers/memory/emif.c | 2 +- > drivers/regulator/pfuze100-regulator.c | 42 ++- > drivers/soc/tegra/pmc.c | 87 +++++-- > include/linux/notifier.h | 7 + > include/linux/pm.h | 1 - > include/linux/reboot.h | 91 +++++++ > kernel/notifier.c | 101 +++++-- > kernel/reboot.c | 347 ++++++++++++++++++++++++- > 27 files changed, 639 insertions(+), 124 deletions(-) > > -- > 2.35.1 >
On 5/18/22 17:46, Rafael J. Wysocki wrote: > On Tue, May 10, 2022 at 1:33 AM Dmitry Osipenko > <dmitry.osipenko@collabora.com> wrote: ... >> Introduce new API that provides call chains support for all restart and >> power-off modes. The new API is designed with simplicity and extensibility >> in mind. ... > The v8 looks much better than the previous versions to me. > > I actually don't really have any comments on it except for the minor > remark regarding patch [1/27] sent separately. > > Please just send an update of that one patch and I will queue up the > series for 5.19. > > However, I'm going to send a pull request with it in the second half > of the merge window, after the majority of the other changes in the > subsystems touched by it have been integrated. Thanks, Rafael. I sent out the updated [1/27] patch to you. For the reference, the updated patch can be found here as well: https://lore.kernel.org/all/20220519105015.1195955-1-dmitry.osipenko@collabora.com/T/#u
Hi Rafael, On Wed, May 18, 2022 at 4:46 PM Rafael J. Wysocki <rafael@kernel.org> wrote: > On Tue, May 10, 2022 at 1:33 AM Dmitry Osipenko > <dmitry.osipenko@collabora.com> wrote: > > m68k: Switch to new sys-off handler API Sorry, I didn't realize this was going to interact with the new m68k virtual machine support, which is included in the m68k pull request for v5.19. > However, I'm going to send a pull request with it in the second half > of the merge window, after the majority of the other changes in the > subsystems touched by it have been integrated. And presumably you will have to merge in v5.19-rc1, too? I've sent a fix. It should appear at https://lore.kernel.org/r/20220523175520.949681-1-geert@linux-m68k.org soon. Can you please include that in your PR? 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
Problem ------- SoC devices require power-off call chaining functionality from kernel. We have a widely used restart chaining provided by restart notifier API, but nothing for power-off. Solution -------- Introduce new API that provides call chains support for all restart and power-off modes. The new API is designed with simplicity and extensibility in mind. This is a third attempt to introduce the new API. First was made by Guenter Roeck back in 2014, second was made by Thierry Reding in 2017. In fact the work didn't stop and recently arm_pm_restart() was removed from v5.14 kernel, which was a part of preparatory work started by Guenter Roeck. Adoption plan ------------- This patchset introduces the new API. It also converts multiple drivers and arch code to the new API to demonstrate how it all looks in practice, removing the pm_power_off_prepare global variable. The plan is: 1. Merge the new API and convert arch code to use do_kernel_power_off(). For now the new API will co-exist with the older API. 2. Convert all drivers and platform code to the new API. 3. Remove obsoleted pm_power_off and pm_power_off_prepare variables. Results ------- 1. Devices can be powered off properly. 2. Global variables are removed from drivers. 3. Global pm_power_off and pm_power_off_prepare callback variables are removed once all users are converted to the new API. The latter callback is removed by patch #24 of this series. 4. Ambiguous call chain ordering is prohibited for non-default priorities. Changelog: v8: - Reworked sys-off handler like was suggested by Rafael Wysocki in the comments to v7. - The struct sys-off handler now is private to kernel/reboot.c and new API is simplified. - There is a single sys-off API function for all handler types. Users shall pass the required sys-off mode type (restart, power-off and etc). - There is single struct sys_off_data callback argument for all handler modes. - User's callback now must return NOTIFY_DONE or NOTIFY_STOP. - The default priority level is zero now. - Multiple handlers now allowed to be registered at the default priority level. - Power-off call chain is atomic now, like the restart chain. - kernel/reboot.c changes are split up into several logical patches. - Added r-b from Michał Mirosław to unmodified patches from v7. - Added acks that were missing in v7 by accident. v7: - Rebased on a recent linux-next. Dropped the recently removed NDS32 architecture. Only SH and x86 arches left un-acked. - Added acks from Thomas Bogendoerfer and Krzysztof Kozlowski to the MIPS and memory/emif patches respectively. - Made couple minor cosmetic improvements to the new API. - A month ago I joined Collabora and continuing to work on this series on the company's time, so changed my email address to collabora.com v6: - Rebased on a recent linux-next. - Made minor couple cosmetic changes. v5: - Dropped patches which cleaned up notifier/reboot headers, as was requested by Rafael Wysocki. - Dropped WARN_ON() from the code, as was requested by Rafael Wysocki. Replaced it with pr_err() appropriately. - Dropped *_notifier_has_unique_priority() functions and added *_notifier_chain_register_unique_prio() instead, as was suggested by Michał Mirosław and Rafael Wysocki. - Dropped export of blocking_notifier_call_chain_is_empty() symbol, as was suggested by Rafael Wysocki. - Michał Mirosław suggested that will be better to split up patch that adds the new API to ease reviewing, but Rafael Wysocki asked not add more patches, so I kept it as a single patch. - Added temporary "weak" stub for pm_power_off() which fixes linkage failure once symbol is removed from arch/* code. Previously I missed this problem because was only compile-testing object files. v4: - Made a very minor improvement to doc comments, clarifying couple default values. - Corrected list of emails recipient by adding Linus, Sebastian, Philipp and more NDS people. Removed bouncing emails. - Added acks that were given to v3. v3: - Renamed power_handler to sys_off_handler as was suggested by Rafael Wysocki. - Improved doc-comments as was suggested by Rafael Wysocki. Added more doc-comments. - Implemented full set of 180 patches which convert whole kernel in accordance to the plan, see link [1] above. Slightly adjusted API to better suit for the remaining converted drivers. * Added unregister_sys_off_handler() that is handy for a couple old platform drivers. * Dropped devm_register_trivial_restart_handler(), 'simple' variant is enough to have. - Improved "Add atomic/blocking_notifier_has_unique_priority()" patch, as was suggested by Andy Shevchenko. Also replaced down_write() with down_read() and factored out common notifier_has_unique_priority(). - Added stop_chain field to struct restart_data and reboot_prep_data after discovering couple drivers wanting that feature. - Added acks that were given to v2. v2: - Replaced standalone power-off call chain demo-API with the combined power-off+restart API because this is what drivers want. It's a more comprehensive solution. - Converted multiple drivers and arch code to the new API. Suggested by Andy Shevchenko. I skimmed through the rest of drivers, verifying that new API suits them. The rest of the drivers will be converted once we will settle on the new API, otherwise will be too many patches here. - v2 API doesn't expose notifier to users and require handlers to have unique priority. Suggested by Guenter Roeck. - v2 API has power-off chaining disabled by default and require drivers to explicitly opt-in to the chaining. This preserves old behaviour for existing drivers once they are converted to the new API. Dmitry Osipenko (27): notifier: Add atomic_notifier_call_chain_is_empty() notifier: Add blocking/atomic_notifier_chain_register_unique_prio() kernel/reboot: Introduce sys-off handler API kernel/reboot: Wrap legacy power-off callbacks into sys-off handlers kernel/reboot: Add do_kernel_power_off() kernel/reboot: Add stub for pm_power_off kernel/reboot: Add kernel_can_power_off() kernel/reboot: Add register_platform_power_off() ARM: Use do_kernel_power_off() csky: Use do_kernel_power_off() riscv: Use do_kernel_power_off() arm64: Use do_kernel_power_off() parisc: Use do_kernel_power_off() xen/x86: Use do_kernel_power_off() powerpc: Use do_kernel_power_off() m68k: Switch to new sys-off handler API sh: Use do_kernel_power_off() x86: Use do_kernel_power_off() ia64: Use do_kernel_power_off() mips: Use do_kernel_power_off() memory: emif: Use kernel_can_power_off() ACPI: power: Switch to sys-off handler API regulator: pfuze100: Use devm_register_sys_off_handler() reboot: Remove pm_power_off_prepare() soc/tegra: pmc: Use sys-off handler API to power off Nexus 7 properly kernel/reboot: Add devm_register_power_off_handler() kernel/reboot: Add devm_register_restart_handler() arch/arm/kernel/reboot.c | 4 +- arch/arm64/kernel/process.c | 3 +- arch/csky/kernel/power.c | 6 +- arch/ia64/kernel/process.c | 4 +- arch/m68k/emu/natfeat.c | 3 +- arch/m68k/include/asm/machdep.h | 1 - arch/m68k/kernel/process.c | 5 +- arch/m68k/kernel/setup_mm.c | 1 - arch/m68k/kernel/setup_no.c | 1 - arch/m68k/mac/config.c | 4 +- arch/mips/kernel/reset.c | 3 +- arch/parisc/kernel/process.c | 4 +- arch/powerpc/kernel/setup-common.c | 4 +- arch/powerpc/xmon/xmon.c | 3 +- arch/riscv/kernel/reset.c | 12 +- arch/sh/kernel/reboot.c | 3 +- arch/x86/kernel/reboot.c | 4 +- arch/x86/xen/enlighten_pv.c | 4 +- drivers/acpi/sleep.c | 16 +- drivers/memory/emif.c | 2 +- drivers/regulator/pfuze100-regulator.c | 42 ++- drivers/soc/tegra/pmc.c | 87 +++++-- include/linux/notifier.h | 7 + include/linux/pm.h | 1 - include/linux/reboot.h | 91 +++++++ kernel/notifier.c | 101 +++++-- kernel/reboot.c | 347 ++++++++++++++++++++++++- 27 files changed, 639 insertions(+), 124 deletions(-)