linux-kernel - Re: [PATCH 7/7] drivers: firmware: psci: Announce support for OS initiated suspend mode

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Message-ID: <20190301173238.GT15517@lakrids.cambridge.arm.com>
Date:   Fri, 1 Mar 2019 17:32:39 +0000
From:   Mark Rutland <mark.rutland@....com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Sudeep Holla <sudeep.holla@....com>,
        Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Lina Iyer <ilina@...eaurora.org>, linux-pm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 7/7] drivers: firmware: psci: Announce support for OS
 initiated suspend mode

On Thu, Feb 28, 2019 at 02:59:19PM +0100, Ulf Hansson wrote:
> PSCI firmware v1.0+, supports two different modes for CPU_SUSPEND. The
> Platform Coordinated mode, which is the default and mandatory mode, while
> support for the OS initiated (OSI) mode is optional.
> 
> In some cases it's interesting for the user/developer to know if the OSI
> mode is supported by the PSCI FW. Therefore, let's print a message to the
> log, if that is the case.
> 
> Cc: Lina Iyer <ilina@...eaurora.org>
> Co-developed-by: Lina Iyer <lina.iyer@...aro.org>
> Reviewed-by: Daniel Lezcano <daniel.lezcano@...aro.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>

Acked-by: Mark Rutland <mark.rutland@....com>

Mark.

> ---
>  drivers/firmware/psci/psci.c | 21 ++++++++++++++++++++-
>  include/uapi/linux/psci.h    |  5 +++++
>  2 files changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index 14d25b54b9f2..417d43886948 100644
> --- a/drivers/firmware/psci/psci.c
> +++ b/drivers/firmware/psci/psci.c
> @@ -95,6 +95,11 @@ static inline bool psci_has_ext_power_state(void)
>  				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
>  }
>  
> +static inline bool psci_has_osi_support(void)
> +{
> +	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
> +}
> +
>  static inline bool psci_power_state_loses_context(u32 state)
>  {
>  	const u32 mask = psci_has_ext_power_state() ?
> @@ -659,10 +664,24 @@ static int __init psci_0_1_init(struct device_node *np)
>  	return 0;
>  }
>  
> +static int __init psci_1_0_init(struct device_node *np)
> +{
> +	int err;
> +
> +	err = psci_0_2_init(np);
> +	if (err)
> +		return err;
> +
> +	if (psci_has_osi_support())
> +		pr_info("OSI mode supported.\n");
> +
> +	return 0;
> +}
> +
>  static const struct of_device_id psci_of_match[] __initconst = {
>  	{ .compatible = "arm,psci",	.data = psci_0_1_init},
>  	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
> -	{ .compatible = "arm,psci-1.0",	.data = psci_0_2_init},
> +	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
>  	{},
>  };
>  
> diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
> index b3bcabe380da..581f72085c33 100644
> --- a/include/uapi/linux/psci.h
> +++ b/include/uapi/linux/psci.h
> @@ -49,6 +49,7 @@
>  
>  #define PSCI_1_0_FN_PSCI_FEATURES		PSCI_0_2_FN(10)
>  #define PSCI_1_0_FN_SYSTEM_SUSPEND		PSCI_0_2_FN(14)
> +#define PSCI_1_0_FN_SET_SUSPEND_MODE		PSCI_0_2_FN(15)
>  
>  #define PSCI_1_0_FN64_SYSTEM_SUSPEND		PSCI_0_2_FN64(14)
>  
> @@ -97,6 +98,10 @@
>  #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK	\
>  			(0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)
>  
> +#define PSCI_1_0_OS_INITIATED			BIT(0)
> +#define PSCI_1_0_SUSPEND_MODE_PC		0
> +#define PSCI_1_0_SUSPEND_MODE_OSI		1
> +
>  /* PSCI return values (inclusive of all PSCI versions) */
>  #define PSCI_RET_SUCCESS			0
>  #define PSCI_RET_NOT_SUPPORTED			-1
> -- 
> 2.17.1
>