Re: [PATCH v3] power: reset: use restart_notifier mechanism for msm-poweroff

From: Kumar Gala
Date: Tue Sep 23 2014 - 13:48:53 EST



On Sep 23, 2014, at 1:28 AM, Pramod Gurav <pramod.gurav@xxxxxxxxxxxxxxx> wrote:

> +linux-arm-msm
> On Tuesday 23 September 2014 11:38 AM, Pramod Gurav wrote:
>> This change replaces use of arm_pm_restart with recently introduced
>> reset mechanism in Linux kernel called restart_notifier.

Can you update the commit message to include details about the priority level we are setting it to.

Probably something like Josh had:

Choose priority 128, as according to documentation, this mechanism "is
sufficient to restart the entire system”.

Hmm, what happens if we have ps_hold restart and msm-poweroff enabled. Which one should have priority?

>>
>> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
>> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
>> Cc: Josh Cartwright <joshc@xxxxxxxxxxxxxx>
>> Cc: Sebastian Reichel <sre@xxxxxxxxxx>
>> Cc: Dmitry Eremin-Solenikov <dbaryshkov@xxxxxxxxx>
>> Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
>> Cc: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
>> Cc: linux-pm@xxxxxxxxxxxxxxx
>>
>> Signed-off-by: Pramod Gurav <pramod.gurav@xxxxxxxxxxxxxxx>
>> ---
>> Tested on Dragonboard APQ8074
>>
>> Changes since v2:
>> - Removed unwanted header file and added linux/pm.h
>>
>> Changes since v1:
>> - Initialized restart_nb with its declaration
>> - Removed return check for register_restart_handler as it always
>> returns 0 as per Guenter's suggestion to Josh's similar patch.
>> This takes care of Guenter's comments on error logs and NULL
>> initialization of restart_nb.notifier_call.
>> ---
>> drivers/power/reset/msm-poweroff.c | 20 ++++++++++++++------
>> 1 file changed, 14 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/power/reset/msm-poweroff.c b/drivers/power/reset/msm-poweroff.c
>> index 774f9a3..4702efd 100644
>> --- a/drivers/power/reset/msm-poweroff.c
>> +++ b/drivers/power/reset/msm-poweroff.c
>> @@ -20,21 +20,27 @@
>> #include <linux/platform_device.h>
>> #include <linux/module.h>
>> #include <linux/reboot.h>
>> -
>> -#include <asm/system_misc.h>
>> +#include <linux/pm.h>
>>
>> static void __iomem *msm_ps_hold;
>> -
>> -static void do_msm_restart(enum reboot_mode reboot_mode, const char *cmd)
>> +static int do_msm_restart(struct notifier_block *nb, unsigned long action,
>> + void *data)
>> {
>> writel(0, msm_ps_hold);
>> mdelay(10000);
>> +
>> + return NOTIFY_DONE;
>> }
>>
>> +static struct notifier_block restart_nb = {
>> + .notifier_call = do_msm_restart,
>> + .priority = 128,
>> +};
>> +
>> static void do_msm_poweroff(void)
>> {
>> /* TODO: Add poweroff capability */
>> - do_msm_restart(REBOOT_HARD, NULL);
>> + do_msm_restart(&restart_nb, 0, NULL);
>> }
>>
>> static int msm_restart_probe(struct platform_device *pdev)
>> @@ -47,8 +53,10 @@ static int msm_restart_probe(struct platform_device *pdev)
>> if (IS_ERR(msm_ps_hold))
>> return PTR_ERR(msm_ps_hold);
>>
>> + register_restart_handler(&restart_nb);
>> +
>> pm_power_off = do_msm_poweroff;
>> - arm_pm_restart = do_msm_restart;
>> +
>> return 0;
>> }
>>
>>
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