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[82.125.3.219]) by mx.google.com with ESMTPSA id k10sm15223488wia.4.2013.06.06.04.40.36 for (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 06 Jun 2013 04:40:37 -0700 (PDT) From: Daniel Lezcano To: rjw@sisk.pl Cc: francescolavra.fl@gmail.com, lenb@kernel.org, linaro-kernel@lists.linaro.org, patches@linaro.org, linux-pm@vger.kernel.org Subject: [PATCH V3 2/2] cpuidle: Comment the driver's framework code Date: Thu, 6 Jun 2013 13:40:31 +0200 Message-Id: <1370518831-19287-2-git-send-email-daniel.lezcano@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1370518831-19287-1-git-send-email-daniel.lezcano@linaro.org> References: <1370518831-19287-1-git-send-email-daniel.lezcano@linaro.org> X-Gm-Message-State: ALoCoQmkEqsdH7cFy3ZPzseQSP6LJA50vMoJlQjRbWd9/dtkhRy0V30xthzsck5mjZibK/DhaV5K X-Original-Sender: daniel.lezcano@linaro.org X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 209.85.220.175 is neither permitted nor denied by best guess record for domain of patch+caf_=patchwork-forward=linaro.org@linaro.org) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Precedence: list Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org List-ID: X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , Added kerneldoc and comments for the cpuidle framework driver's code. Signed-off-by: Daniel Lezcano --- drivers/cpuidle/driver.c | 128 +++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 120 insertions(+), 8 deletions(-) diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index 745adae..0268346 100644 --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -22,11 +22,28 @@ DEFINE_SPINLOCK(cpuidle_driver_lock); static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers); +/** + * __cpuidle_get_cpu_driver: returns the cpuidle driver tied with the specified + * cpu. + * + * @cpu: an integer specifying the cpu number + * + * Returns a pointer to struct cpuidle_driver, NULL if no driver has been + * registered for this driver + */ static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) { return per_cpu(cpuidle_drivers, cpu); } +/** + * __cpuidle_set_driver: assign to the per cpu variable the driver pointer for + * each cpu the driver is assigned to with the cpumask. + * + * @drv: a pointer to a struct cpuidle_driver + * + * Returns 0 on success, < 0 otherwise + */ static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) { int cpu; @@ -42,6 +59,12 @@ static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) return 0; } +/** + * __cpuidle_unset_driver: for each cpu the driver is handling, set the per cpu + * variable driver to NULL. + * + * @drv: a pointer to a struct cpuidle_driver + */ static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) { int cpu; @@ -59,11 +82,27 @@ static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) static struct cpuidle_driver *cpuidle_curr_driver; +/** + * __cpuidle_get_cpu_driver: returns the global cpuidle driver pointer. + * + * @cpu: an integer specifying the cpu number, this parameter is ignored + * + * Returns a pointer to a struct cpuidle_driver, NULL if no driver was + * previously registered + */ static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) { return cpuidle_curr_driver; } +/** + * __cpuidle_set_driver: assign the cpuidle driver pointer to the global cpuidle + * driver variable. + * + * @drv: a pointer to a struct cpuidle_driver + * + * Returns 0 on success, < 0 otherwise + */ static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) { if (cpuidle_curr_driver) @@ -74,6 +113,12 @@ static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) return 0; } +/** + * __cpuidle_unset_driver: reset the global cpuidle driver variable if the + * cpuidle driver pointer match it. + * + * @drv: a pointer to a struct cpuidle_driver + */ static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) { if (drv == cpuidle_curr_driver) @@ -82,21 +127,49 @@ static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) #endif +/** + * cpuidle_setup_broadcast_timer: set the broadcast timer notification for the + * current cpu. This function is called per cpu context invoked by a smp cross + * call. It is not supposed to be called directly. + * + * @arg: a void pointer, actually used to match the smp cross call api but used + * as a long with two values: + * - CLOCK_EVT_NOTIFY_BROADCAST_ON + * - CLOCK_EVT_NOTIFY_BROADCAST_OFF + */ static void cpuidle_setup_broadcast_timer(void *arg) { int cpu = smp_processor_id(); clockevents_notify((long)(arg), &cpu); } +/** + * __cpuidle_driver_init: initialize the driver internal data. + * + * @drv: a valid pointer to a struct cpuidle_driver + * + * Returns 0 on success, < 0 otherwise + */ static int __cpuidle_driver_init(struct cpuidle_driver *drv) { int i; drv->refcnt = 0; + /* + * we default here to all cpu possible because if the kernel + * boots with some cpus offline and then we online one of them + * the cpu notifier won't know which driver to assign + */ if (!drv->cpumask) drv->cpumask = (struct cpumask *)cpu_possible_mask; + /* + * we look for the timer stop flag in the different states, + * so know we have to setup the broadcast timer. The loop is + * in reverse order, because usually the deeper state has this + * flag set + */ for (i = drv->state_count - 1; i >= 0 ; i--) { if (!(drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP)) @@ -109,6 +182,16 @@ static int __cpuidle_driver_init(struct cpuidle_driver *drv) return 0; } +/** + * __cpuidle_register_driver: do some sanity checks, initializes the driver, + * assign the driver to the global cpuidle driver variable(s) and setup the + * broadcast timer if the cpuidle driver has some states which shutdown the + * local timer. + * + * @drv: a valid pointer to a struct cpuidle_driver + * + * Returns 0 on success, < 0 otherwise + */ static int __cpuidle_register_driver(struct cpuidle_driver *drv) { int ret; @@ -135,8 +218,12 @@ static int __cpuidle_register_driver(struct cpuidle_driver *drv) } /** - * cpuidle_unregister_driver - unregisters a driver - * @drv: the driver + * __cpuidle_unregister_driver: checks the driver is no longer in use, reset the + * global cpuidle driver variable(s) and disable the timer broadcast + * notification mechanism if it was in use. + * + * @drv: a valid pointer to a struct cpuidle_driver + * */ static void __cpuidle_unregister_driver(struct cpuidle_driver *drv) { @@ -153,8 +240,12 @@ static void __cpuidle_unregister_driver(struct cpuidle_driver *drv) } /** - * cpuidle_register_driver - registers a driver - * @drv: the driver + * cpuidle_register_driver: registers a driver by taking a lock to prevent + * multiple callers to [un]register a driver at the same time. + * + * @drv: a pointer to a valid struct cpuidle_driver + * + * Returns 0 on success, < 0 otherwise */ int cpuidle_register_driver(struct cpuidle_driver *drv) { @@ -169,8 +260,11 @@ int cpuidle_register_driver(struct cpuidle_driver *drv) EXPORT_SYMBOL_GPL(cpuidle_register_driver); /** - * cpuidle_unregister_driver - unregisters a driver - * @drv: the driver + * cpuidle_unregister_driver: unregisters a driver by taking a lock to prevent + * multiple callers to [un]register a driver at the same time. The specified + * driver must match the driver currently registered. + * + * @drv: a pointer to a valid struct cpuidle_driver */ void cpuidle_unregister_driver(struct cpuidle_driver *drv) { @@ -181,7 +275,9 @@ void cpuidle_unregister_driver(struct cpuidle_driver *drv) EXPORT_SYMBOL_GPL(cpuidle_unregister_driver); /** - * cpuidle_get_driver - return the current driver + * cpuidle_get_driver: returns the driver tied with the current cpu. + * + * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered */ struct cpuidle_driver *cpuidle_get_driver(void) { @@ -197,7 +293,12 @@ struct cpuidle_driver *cpuidle_get_driver(void) EXPORT_SYMBOL_GPL(cpuidle_get_driver); /** - * cpuidle_get_cpu_driver - return the driver tied with a cpu + * cpuidle_get_cpu_driver: returns the driver registered with a cpu. + * + * @dev: a valid pointer to a struct cpuidle_device + * + * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered + * for the specified cpu */ struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev) { @@ -208,6 +309,13 @@ struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev) } EXPORT_SYMBOL_GPL(cpuidle_get_cpu_driver); +/** + * cpuidle_driver_ref: gets a refcount for the driver. Note this function takes + * a refcount for the driver assigned to the current cpu. + * + * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered + * for the current cpu + */ struct cpuidle_driver *cpuidle_driver_ref(void) { struct cpuidle_driver *drv; @@ -221,6 +329,10 @@ struct cpuidle_driver *cpuidle_driver_ref(void) return drv; } +/** + * cpuidle_driver_unref: puts down the refcount for the driver. Note this + * function decrement the refcount for the driver assigned to the current cpu. + */ void cpuidle_driver_unref(void) { struct cpuidle_driver *drv = cpuidle_get_driver();