Re: [PATCH 3/6] drivers: firmware: psci: Register with kernel restart handler

From: Stefan Agner <stefan@agner•ch>
To: Thierry Reding <thierry.reding@gmail•com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm•com>,
	Arnd Bergmann <arnd@arndb•de>,
	Stefano Stabellini <stefano.stabellini@eu•citrix.com>,
	Catalin Marinas <catalin.marinas@arm•com>,
	Russell King <linux@armlinux•org.uk>,
	linux-kernel@vger•kernel.org,
	Wolfram Sang <wsa+renesas@sang-engineering•com>,
	arm@kernel•org, linux-arm-kernel@lists•infradead.org,
	Olof Johansson <olof@lixom•net>,
	Guenter Roeck <linux@roeck-us•net>
Subject: Re: [PATCH 3/6] drivers: firmware: psci: Register with kernel restart handler
Date: Wed, 16 Oct 2019 09:46:10 +0200	[thread overview]
Message-ID: <e354a51deb667269744d6f415c711297@agner.ch> (raw)
In-Reply-To: <20191015145147.1106247-4-thierry.reding@gmail.com>

On 2019-10-15 16:51, Thierry Reding wrote:
> From: Guenter Roeck <linux@roeck-us•net>
> 
> 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.
> 
> Acked-by: Arnd Bergmann <arnd@arndb•de>
> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering•com>
> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering•com>
> Signed-off-by: Guenter Roeck <linux@roeck-us•net>
> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm•com>
> Signed-off-by: Thierry Reding <treding@nvidia•com>

Looks good to me! And helps also in my case, a board which has a broken
PSCI reset capability.

Reviewed-by: Stefan Agner <stefan.agner@toradex•com>

--
Stefan

> ---
>  drivers/firmware/psci/psci.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index 84f4ff351c62..a41c6ba043a2 100644
> --- a/drivers/firmware/psci/psci.c
> +++ b/drivers/firmware/psci/psci.c
> @@ -250,7 +250,8 @@ 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 *nb, unsigned long action,
> +			  void *data)
>  {
>  	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
>  	    psci_system_reset2_supported) {
> @@ -263,8 +264,15 @@ static void psci_sys_reset(enum reboot_mode
> reboot_mode, const char *cmd)
>  	} else {
>  		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);
> @@ -431,7 +439,7 @@ 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;
>  }

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