From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760380AbcDMNKr (ORCPT ); Wed, 13 Apr 2016 09:10:47 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:49397 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758252AbcDMNKp (ORCPT ); Wed, 13 Apr 2016 09:10:45 -0400 Subject: Re: [PATCH 3/6] ARM: PSCI: Register with kernel restart handler To: Mark Rutland References: <1460120039-2497-1-git-send-email-linux@roeck-us.net> <1460120039-2497-4-git-send-email-linux@roeck-us.net> <20160413110519.GE32018@leverpostej> Cc: Russell King , Catalin Marinas , Wolfram Sang , Geert Uytterhoeven , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Lorenzo Pieralisi From: Guenter Roeck Message-ID: <570E4550.5000207@roeck-us.net> Date: Wed, 13 Apr 2016 06:10:40 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <20160413110519.GE32018@leverpostej> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/13/2016 04:05 AM, Mark Rutland wrote: > On Fri, Apr 08, 2016 at 05:53:56AM -0700, Guenter Roeck wrote: >> Register with kernel restart handler instead of setting arm_pm_restart >> directly. This enables support for replacing the PSCI restart handler >> with a different handler if necessary for a specific board. >> >> Select a priority of 129 to indicate a higher than default priority, but >> keep it as low as possible since PSCI reset is known to fail on some >> boards. > > For reference, which boards? > Salvator-X, reported by Geert Uytterhoeven. Wolfram Sang also reported that it is broken on a board he is using, but I don't recall if it is the same board. > It's unfortunate that that a PSCI 0.2+ implementation would be lacking a > working SYSTEM_RESET implementation, and it's certainly a mistake to > discourage. > >> Signed-off-by: Guenter Roeck >> --- >> It might make sense to introduce a restart-priority property for devicetree >> based configurations, but I am not sure if this would be acceptable. > >>>From the DT side, I'm not keen on properties for priorities. They're > incredibly fragile and don't really encode a HW property. > Depends. It is a convenient means to say "primary restart method" or "may be broken". > A better option would be to have a property to describe how the PSCI > implementation is broken (e.g. broken-system-reset), and not register > the handler at all in that case. > ... just like this. I'll look into it. Thanks, Guenter > Thanks, > Mark. > >> drivers/firmware/psci.c | 11 +++++++++-- >> 1 file changed, 9 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c >> index 11bfee8b79a9..99fab3ac3fd5 100644 >> --- a/drivers/firmware/psci.c >> +++ b/drivers/firmware/psci.c >> @@ -231,11 +231,18 @@ static int get_set_conduit_method(struct device_node *np) >> return 0; >> } >> >> -static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd) >> +static int psci_sys_reset(struct notifier_block *np, unsigned long action, >> + void *data) >> { >> invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0); >> + return NOTIFY_DONE; >> } >> >> +static struct notifier_block psci_sys_reset_nb = { >> + .notifier_call = psci_sys_reset, >> + .priority = 129, >> +}; >> + >> static void psci_sys_poweroff(void) >> { >> invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0); >> @@ -461,7 +468,7 @@ static void __init psci_0_2_set_functions(void) >> >> psci_ops.migrate_info_type = psci_migrate_info_type; >> >> - arm_pm_restart = psci_sys_reset; >> + register_restart_handler(&psci_sys_reset_nb); >> >> pm_power_off = psci_sys_poweroff; >> } >> -- >> 2.5.0 >> > From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@roeck-us.net (Guenter Roeck) Date: Wed, 13 Apr 2016 06:10:40 -0700 Subject: [PATCH 3/6] ARM: PSCI: Register with kernel restart handler In-Reply-To: <20160413110519.GE32018@leverpostej> References: <1460120039-2497-1-git-send-email-linux@roeck-us.net> <1460120039-2497-4-git-send-email-linux@roeck-us.net> <20160413110519.GE32018@leverpostej> Message-ID: <570E4550.5000207@roeck-us.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 04/13/2016 04:05 AM, Mark Rutland wrote: > On Fri, Apr 08, 2016 at 05:53:56AM -0700, Guenter Roeck wrote: >> Register with kernel restart handler instead of setting arm_pm_restart >> directly. This enables support for replacing the PSCI restart handler >> with a different handler if necessary for a specific board. >> >> Select a priority of 129 to indicate a higher than default priority, but >> keep it as low as possible since PSCI reset is known to fail on some >> boards. > > For reference, which boards? > Salvator-X, reported by Geert Uytterhoeven. Wolfram Sang also reported that it is broken on a board he is using, but I don't recall if it is the same board. > It's unfortunate that that a PSCI 0.2+ implementation would be lacking a > working SYSTEM_RESET implementation, and it's certainly a mistake to > discourage. > >> Signed-off-by: Guenter Roeck >> --- >> It might make sense to introduce a restart-priority property for devicetree >> based configurations, but I am not sure if this would be acceptable. > >>>From the DT side, I'm not keen on properties for priorities. They're > incredibly fragile and don't really encode a HW property. > Depends. It is a convenient means to say "primary restart method" or "may be broken". > A better option would be to have a property to describe how the PSCI > implementation is broken (e.g. broken-system-reset), and not register > the handler at all in that case. > ... just like this. I'll look into it. Thanks, Guenter > Thanks, > Mark. > >> drivers/firmware/psci.c | 11 +++++++++-- >> 1 file changed, 9 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c >> index 11bfee8b79a9..99fab3ac3fd5 100644 >> --- a/drivers/firmware/psci.c >> +++ b/drivers/firmware/psci.c >> @@ -231,11 +231,18 @@ static int get_set_conduit_method(struct device_node *np) >> return 0; >> } >> >> -static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd) >> +static int psci_sys_reset(struct notifier_block *np, unsigned long action, >> + void *data) >> { >> invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0); >> + return NOTIFY_DONE; >> } >> >> +static struct notifier_block psci_sys_reset_nb = { >> + .notifier_call = psci_sys_reset, >> + .priority = 129, >> +}; >> + >> static void psci_sys_poweroff(void) >> { >> invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0); >> @@ -461,7 +468,7 @@ static void __init psci_0_2_set_functions(void) >> >> psci_ops.migrate_info_type = psci_migrate_info_type; >> >> - arm_pm_restart = psci_sys_reset; >> + register_restart_handler(&psci_sys_reset_nb); >> >> pm_power_off = psci_sys_poweroff; >> } >> -- >> 2.5.0 >> >