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From: Guenter Roeck <linux@roeck-us.net>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Wolfram Sang <wsa@the-dreams.de>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Subject: Re: [PATCH 3/6] ARM: PSCI: Register with kernel restart handler
Date: Wed, 13 Apr 2016 06:10:40 -0700	[thread overview]
Message-ID: <570E4550.5000207@roeck-us.net> (raw)
In-Reply-To: <20160413110519.GE32018@leverpostej>

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 <linux@roeck-us.net>
>> ---
>> 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
>>
>

WARNING: multiple messages have this Message-ID
From: linux@roeck-us.net (Guenter Roeck)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/6] ARM: PSCI: Register with kernel restart handler
Date: Wed, 13 Apr 2016 06:10:40 -0700	[thread overview]
Message-ID: <570E4550.5000207@roeck-us.net> (raw)
In-Reply-To: <20160413110519.GE32018@leverpostej>

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 <linux@roeck-us.net>
>> ---
>> 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
>>
>

  parent reply	other threads:[~2016-04-13 13:10 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-08 12:53 [PATCH 0/6] ARM/ARM64: Drop arm_pm_restart Guenter Roeck
2016-04-08 12:53 ` Guenter Roeck
2016-04-08 12:53 ` [PATCH 1/6] ARM: prima2: Register with kernel restart handler Guenter Roeck
2016-04-08 12:53   ` Guenter Roeck
2016-04-08 12:53 ` [PATCH 2/6] ARM: xen: " Guenter Roeck
2016-04-08 12:53   ` Guenter Roeck
2016-04-08 12:53   ` Guenter Roeck
2016-04-08 15:22   ` Konrad Rzeszutek Wilk
2016-04-08 18:20     ` Guenter Roeck
2016-04-08 18:20     ` [Xen-devel] " Guenter Roeck
2016-04-08 18:20       ` Guenter Roeck
2016-04-09 23:46   ` Stefano Stabellini
2016-04-09 23:46     ` Stefano Stabellini
2016-04-09 23:56     ` Stefano Stabellini
2016-04-09 23:56       ` Stefano Stabellini
2016-04-09 23:56     ` Stefano Stabellini
2016-04-09 23:46   ` Stefano Stabellini
2016-04-08 12:53 ` [PATCH 3/6] ARM: PSCI: " Guenter Roeck
2016-04-08 12:53   ` Guenter Roeck
2016-04-12 15:36   ` Wolfram Sang
2016-04-12 15:36     ` Wolfram Sang
2016-04-13 11:05   ` Mark Rutland
2016-04-13 11:05     ` Mark Rutland
2016-04-13 11:24     ` Jisheng Zhang
2016-04-13 11:24       ` Jisheng Zhang
2016-04-13 13:10     ` Guenter Roeck [this message]
2016-04-13 13:10       ` Guenter Roeck
2016-04-13 13:22       ` Geert Uytterhoeven
2016-04-13 13:22         ` Geert Uytterhoeven
2016-04-14  0:42         ` Guenter Roeck
2016-04-14  0:42           ` Guenter Roeck
2016-04-14  8:52           ` Wolfram Sang
2016-04-14  8:52             ` Wolfram Sang
2016-04-14 13:21             ` Guenter Roeck
2016-04-14 13:21               ` Guenter Roeck
2016-04-14 14:31               ` Wolfram Sang
2016-04-14 14:31                 ` Wolfram Sang
2016-04-08 12:53 ` [PATCH 4/6] ARM: " Guenter Roeck
2016-04-08 12:53   ` Guenter Roeck
2016-04-08 12:53 ` [PATCH 5/6] ARM64: Remove arm_pm_restart Guenter Roeck
2016-04-08 12:53   ` Guenter Roeck
2016-04-12 13:10   ` Catalin Marinas
2016-04-12 13:10     ` Catalin Marinas
2016-04-08 12:53 ` [PATCH 6/6] ARM: " Guenter Roeck
2016-04-08 12:53   ` Guenter Roeck
2016-04-08 15:44 ` [PATCH 0/6] ARM/ARM64: Drop arm_pm_restart Wolfram Sang
2016-04-08 15:44   ` Wolfram Sang
2016-04-08 20:46 ` Arnd Bergmann
2016-04-08 20:46   ` Arnd Bergmann
2016-04-12 15:41 ` Wolfram Sang
2016-04-12 15:41   ` Wolfram Sang

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