linux-kernel - Re: [PATCH v10 17/27] drivers: firmware: psci: Prepare to support PM domains

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Date:   Thu, 20 Dec 2018 15:19:23 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Ulf Hansson <ulf.hansson@...aro.org>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Sudeep Holla <sudeep.holla@....com>,
        Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
        Mark Rutland <mark.rutland@....com>, linux-pm@...r.kernel.org
Cc:     "Raju P . L . S . S . S . N" <rplsssn@...eaurora.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Tony Lindgren <tony@...mide.com>,
        Kevin Hilman <khilman@...nel.org>,
        Lina Iyer <ilina@...eaurora.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v10 17/27] drivers: firmware: psci: Prepare to support PM
 domains

On 29/11/2018 18:46, Ulf Hansson wrote:
> Following changes are about to implement support for PM domains to PSCI.
> Those changes are mainly going to be implemented in a new separate file,
> hence a couple of the internal PSCI functions needs to be shared to be
> accessible. So, let's do that via adding new PSCI header file.
> 
> Moreover, the changes deploying support for PM domains, needs to be able to
> switch the PSCI FW into the OS initiated mode. For that reason, let's add a
> new function that deals with this and share it via the new PSCI header
> file.
> 
> Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
> ---
> 
> Changes in v10:
> 	- New patch. Re-places the earlier patch: "drivers: firmware: psci:
> 	  Share a few internal PSCI functions".
> 
> ---
>  drivers/firmware/psci/psci.c | 28 +++++++++++++++++++++-------
>  drivers/firmware/psci/psci.h | 14 ++++++++++++++
>  2 files changed, 35 insertions(+), 7 deletions(-)
>  create mode 100644 drivers/firmware/psci/psci.h
> 
> diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> index 8dbcdecc2ae4..623591b541a4 100644
> --- a/drivers/firmware/psci/psci.c
> +++ b/drivers/firmware/psci/psci.c
> @@ -34,6 +34,8 @@
>  #include <asm/smp_plat.h>
>  #include <asm/suspend.h>
>  
> +#include "psci.h"
> +
>  /*
>   * While a 64-bit OS can make calls with SMC32 calling conventions, for some
>   * calls it is necessary to use SMC64 to pass or return 64-bit values.
> @@ -90,23 +92,35 @@ static u32 psci_function_id[PSCI_FN_MAX];
>  static DEFINE_PER_CPU(u32, domain_state);
>  static u32 psci_cpu_suspend_feature;
>  
> -static inline u32 psci_get_domain_state(void)
> +u32 psci_get_domain_state(void)
>  {
>  	return __this_cpu_read(domain_state);
>  }
>
> -static inline void psci_set_domain_state(u32 state)
> +void psci_set_domain_state(u32 state)
>  {
>  	__this_cpu_write(domain_state, state);
>  }
>  
> +bool psci_set_osi_mode(void)
> +{
> +	int ret;
> +
> +	ret = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE,
> +			PSCI_1_0_SUSPEND_MODE_OSI, 0, 0);
> +	if (ret)
> +		pr_warn("failed to enable OSI mode: %d\n", ret);
> +
> +	return !ret;
> +}

Please keep the convention with the error code (0 => success)

In the next patch it can be called:

if (psci_has_osi_support())
	osi_mode_enabled = psci_set_osi_mode() ? false : true;

> +
>  static inline bool psci_has_ext_power_state(void)
>  {
>  	return psci_cpu_suspend_feature &
>  				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
>  }
>  
> -static inline bool psci_has_osi_support(void)
> +bool psci_has_osi_support(void)
>  {
>  	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
>  }
> @@ -285,10 +299,7 @@ static int __init psci_features(u32 psci_func_id)
>  			      psci_func_id, 0, 0);
>  }
>  
> -#ifdef CONFIG_CPU_IDLE
> -static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
> -
> -static int psci_dt_parse_state_node(struct device_node *np, u32 *state)
> +int psci_dt_parse_state_node(struct device_node *np, u32 *state)
>  {
>  	int err = of_property_read_u32(np, "arm,psci-suspend-param", state);
>  
> @@ -305,6 +316,9 @@ static int psci_dt_parse_state_node(struct device_node *np, u32 *state)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_CPU_IDLE

It would be nicer if you can remove the CONFIG_CPU_IDLE by replacing it
with a specific one (eg. CONFIG_PSCI_IDLE) and make it depend on
CONFIG_CPU_IDLE, so the config options stay contained in their
respective subsystems directory.

> +static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
> +
>  static int psci_dt_cpu_init_idle(struct cpuidle_driver *drv,
>  			struct device_node *cpu_node, int cpu)
>  {
> diff --git a/drivers/firmware/psci/psci.h b/drivers/firmware/psci/psci.h
> new file mode 100644
> index 000000000000..7d9d38fd57e1
> --- /dev/null
> +++ b/drivers/firmware/psci/psci.h
> @@ -0,0 +1,14 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef __PSCI_H
> +#define __PSCI_H
> +
> +struct device_node;
> +
> +bool psci_set_osi_mode(void);
> +u32 psci_get_domain_state(void);
> +void psci_set_domain_state(u32 state);
> +bool psci_has_osi_support(void);
> +int psci_dt_parse_state_node(struct device_node *np, u32 *state);
> +
> +#endif /* __PSCI_H */
> 


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