From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Date: Fri, 06 May 2022 15:28:49 +0000 Subject: Re: [PATCH v7 04/20] kernel: Add combined power-off+restart handler call chain API Message-Id: <296e6f6f-e96d-2db1-77b9-288dc47d1b98@collabora.com> List-Id: References: <20220411233832.391817-1-dmitry.osipenko@collabora.com> <20220411233832.391817-5-dmitry.osipenko@collabora.com> <990621e7-9f8a-8b4a-02ec-fd6c1e1f48ff@collabora.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Rafael J. Wysocki" Cc: Thierry Reding , Jonathan Hunter , Russell King , Catalin Marinas , Will Deacon , Guo Ren , Geert Uytterhoeven , Greg Ungerer , Joshua Thompson , Thomas Bogendoerfer , Sebastian Reichel , Linus Walleij , Philipp Zabel , Greentime Hu , Vincent Chen , "James E.J. Bottomley" , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Paul Walmsley , Palmer Dabbelt , Albert Ou , Yoshinori Sato , Rich Felker , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , the arch/x86 maintainers , "H. Peter Anvin" , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , Len Brown , Santosh Shilimkar , Krzysztof Kozlowski , Liam Girdwood , Mark Brown , Pavel Machek , Lee Jones , Andrew Morton , Guenter Roeck , Daniel Lezcano , Andy Shevchenko , Ulf Hansson , =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , Linux Kernel Mailing List , linux-csky@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, "open list:BROADCOM NVRAM DRIVER" , linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, Linux-sh list , xen-devel@lists.xenproject.org, ACPI Devel Maling List , Linux PM , linux-tegra On 4/20/22 21:47, Rafael J. Wysocki wrote: >>>> + spin_unlock(&platform_power_off_lock); >>>> + >>>> + if (ret) >>>> + return ret; >>>> + >>>> + ret = register_power_off_handler(&priv->power_off_nb); >>>> + if (ret) >>>> + priv->platform_power_off_cb = NULL; >>>> + >>>> + return ret; >>>> +} >>>> +EXPORT_SYMBOL_GPL(register_platform_power_off); >>>> + >>>> +/** >>>> + * unregister_platform_power_off - Unregister platform-level power-off callback >>>> + * @power_off: Power-off callback >>>> + * >>>> + * Unregisters previously registered platform power-off callback. >>>> + * >>>> + * Returns zero on success, or error code on failure. >>>> + */ >>>> +int unregister_platform_power_off(void (*power_off)(void)) >>>> +{ >>>> + struct sys_off_handler_private_data *priv; >>>> + int ret; >>>> + >>>> + priv = sys_off_handler_private_data(&platform_power_off_handler); >>>> + >>>> + if (priv->platform_power_off_cb != power_off) >>>> + return -EINVAL; >>>> + >>>> + ret = unregister_power_off_handler(&priv->power_off_nb); >>>> + priv->platform_power_off_cb = NULL; >>>> + >>>> + return ret; >>>> +} >>>> +EXPORT_SYMBOL_GPL(unregister_platform_power_off); >>>> + >>>> +/** >>>> + * do_kernel_power_off - Execute kernel power-off handler call chain >>>> + * >>>> + * Calls functions registered with register_power_off_handler. >>>> + * >>>> + * Expected to be called as last step of the power-off sequence. >>>> + * >>>> + * Powers off the system immediately if a power-off handler function has >>>> + * been registered. Otherwise does nothing. >>>> + */ >>>> +void do_kernel_power_off(void) >>>> +{ >>>> + /* legacy pm_power_off() is unchained and has highest priority */ >>>> + if (pm_power_off && pm_power_off != dummy_pm_power_off) >>>> + return pm_power_off(); >>>> + >>>> + blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_NORMAL, >>>> + NULL); >>>> +} >>>> + >>>> +static void do_kernel_power_off_prepare(void) >>>> +{ >>>> + /* legacy pm_power_off_prepare() is unchained and has highest priority */ >>>> + if (pm_power_off_prepare) >>>> + return pm_power_off_prepare(); >>>> + >>>> + blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_PREPARE, >>>> + NULL); >>>> +} >>>> + >>>> /** >>>> * kernel_power_off - power_off the system >>>> * >>>> @@ -304,8 +893,7 @@ EXPORT_SYMBOL_GPL(kernel_halt); >>>> void kernel_power_off(void) >>>> { >>>> kernel_shutdown_prepare(SYSTEM_POWER_OFF); >>>> - if (pm_power_off_prepare) >>>> - pm_power_off_prepare(); >>>> + do_kernel_power_off_prepare(); >>>> migrate_to_reboot_cpu(); >>>> syscore_shutdown(); >>>> pr_emerg("Power down\n"); >>>> @@ -314,6 +902,16 @@ void kernel_power_off(void) >>>> } >>>> EXPORT_SYMBOL_GPL(kernel_power_off); >>>> >>>> +bool kernel_can_power_off(void) >>>> +{ >>>> + if (!pm_power_off && >>>> + blocking_notifier_call_chain_is_empty(&power_off_handler_list)) >>>> + return false; >>>> + >>>> + return true; >>> return pm_power_off || >>> blocking_notifier_call_chain_is_empty(&power_off_handler_list); >> Thank you for the thorough review! > You're very welcome! Thanks again for taking a look at the patches. I don't have strong preferences about the names and etc, so I'll update it all in v8 like you suggested. -- Best regards, Dmitry