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Wysocki" , Kevin Hilman , Ulf Hansson , Pavel Machek , Len Brown , Greg Kroah-Hartman , Bjorn Andersson , Andy Gross , Konrad Dybcio , Mike Turquette , Stephen Boyd , Taniya Das Cc: linux-pm@vger.kernel.org, Linux Kernel Mailing List , linux-arm-msm@vger.kernel.org Subject: [PATCH v3 1/5] PM: domains: Allow devices attached to genpd to be managed by HW Date: Wed, 23 Aug 2023 14:45:24 +0300 Message-Id: <20230823114528.3677667-2-abel.vesa@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230823114528.3677667-1-abel.vesa@linaro.org> References: <20230823114528.3677667-1-abel.vesa@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Ulf Hansson Some power-domains may be capable of relying on the HW to control the power for a device that's hooked up to it. Typically, for these kinds of configurations the device doesn't really need to be attached to a PM domain (genpd), from Linux point of view. However, in some cases the behaviour of the power-domain and its device can be changed in runtime. To allow a consumer driver to change the behaviour of the PM domain for its device, let's provide a new function, dev_pm_genpd_set_hwmode(). Moreover, let's add a corresponding optional genpd callback, ->set_hwmode_dev(), which the genpd provider should implement if it can support switching between HW controlled mode and SW controlled mode. Similarly, add the dev_pm_genpd_get_hwmode() to allow consumers to read the current mode and its corresponding optional genpd callback, ->get_hwmode_dev(), which the genpd provider can also implement for reading back the mode from the hardware. Signed-off-by: Ulf Hansson Signed-off-by: Abel Vesa --- Changes since v2: * None drivers/base/power/domain.c | 69 +++++++++++++++++++++++++++++++++++++ include/linux/pm_domain.h | 17 +++++++++ 2 files changed, 86 insertions(+) diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index 5cb2023581d4..dfb4f1de540d 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -541,6 +541,75 @@ void dev_pm_genpd_synced_poweroff(struct device *dev) } EXPORT_SYMBOL_GPL(dev_pm_genpd_synced_poweroff); =20 +/** + * dev_pm_genpd_set_hwmode - Set the HW mode for the device and its PM dom= ain. + * + * @dev: Device for which the HW-mode should be changed. + * @enable: Value to set or unset the HW-mode. + * + * Some PM domains can rely on HW signals to control the power for a devic= e. To + * allow a consumer driver to switch the behaviour for its device in runti= me, + * which may be beneficial from a latency or energy point of view, this fu= nction + * may be called. + * + * It is assumed that the users guarantee that the genpd wouldn't be detac= hed + * while this routine is getting called. + * + * Returns 0 on success and negative error values on failures. + */ +int dev_pm_genpd_set_hwmode(struct device *dev, bool enable) +{ + struct generic_pm_domain *genpd; + int ret =3D 0; + + genpd =3D dev_to_genpd_safe(dev); + if (!genpd) + return -ENODEV; + + if (!genpd->set_hwmode_dev) + return -EOPNOTSUPP; + + genpd_lock(genpd); + + if (dev_gpd_data(dev)->hw_mode =3D=3D enable) + goto out; + + ret =3D genpd->set_hwmode_dev(genpd, dev, enable); + if (!ret) + dev_gpd_data(dev)->hw_mode =3D enable; + +out: + genpd_unlock(genpd); + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_genpd_set_hwmode); + +/** + * dev_pm_genpd_get_hwmode - Get the HW mode setting for the device. + * + * @dev: Device for which the current HW-mode setting should be fetched. + * + * This helper function allows consumer drivers to fetch the current HW mo= de + * setting of its the device. + * + * It is assumed that the users guarantee that the genpd wouldn't be detac= hed + * while this routine is getting called. + */ +bool dev_pm_genpd_get_hwmode(struct device *dev) +{ + struct generic_pm_domain *genpd; + + genpd =3D dev_to_genpd_safe(dev); + if (!genpd) + return false; + + if (genpd->get_hwmode_dev) + return genpd->get_hwmode_dev(genpd, dev); + + return dev_gpd_data(dev)->hw_mode; +} +EXPORT_SYMBOL_GPL(dev_pm_genpd_get_hwmode); + static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed) { unsigned int state_idx =3D genpd->state_idx; diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index f776fb93eaa0..36d308ba40b0 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -146,6 +146,10 @@ struct generic_pm_domain { int (*set_performance_state)(struct generic_pm_domain *genpd, unsigned int state); struct gpd_dev_ops dev_ops; + int (*set_hwmode_dev)(struct generic_pm_domain *domain, + struct device *dev, bool enable); + bool (*get_hwmode_dev)(struct generic_pm_domain *domain, + struct device *dev); int (*attach_dev)(struct generic_pm_domain *domain, struct device *dev); void (*detach_dev)(struct generic_pm_domain *domain, @@ -208,6 +212,7 @@ struct generic_pm_domain_data { unsigned int performance_state; unsigned int default_pstate; unsigned int rpm_pstate; + bool hw_mode; void *data; }; =20 @@ -237,6 +242,8 @@ int dev_pm_genpd_remove_notifier(struct device *dev); void dev_pm_genpd_set_next_wakeup(struct device *dev, ktime_t next); ktime_t dev_pm_genpd_get_next_hrtimer(struct device *dev); void dev_pm_genpd_synced_poweroff(struct device *dev); +int dev_pm_genpd_set_hwmode(struct device *dev, bool enable); +bool dev_pm_genpd_get_hwmode(struct device *dev); =20 extern struct dev_power_governor simple_qos_governor; extern struct dev_power_governor pm_domain_always_on_gov; @@ -305,6 +312,16 @@ static inline ktime_t dev_pm_genpd_get_next_hrtimer(st= ruct device *dev) static inline void dev_pm_genpd_synced_poweroff(struct device *dev) { } =20 +static inline int dev_pm_genpd_set_hwmode(struct device *dev, bool enable) +{ + return -EOPNOTSUPP; +} + +static inline bool dev_pm_genpd_get_hwmode(struct device *dev) +{ + return false; +} + #define simple_qos_governor (*(struct dev_power_governor *)(NULL)) #define pm_domain_always_on_gov (*(struct dev_power_governor *)(NULL)) #endif --=20 2.34.1