diff options
Diffstat (limited to 'drivers/base/power/clock_ops.c')
| -rw-r--r-- | drivers/base/power/clock_ops.c | 805 |
1 files changed, 805 insertions, 0 deletions
diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c new file mode 100644 index 0000000000..4110c19c08 --- /dev/null +++ b/drivers/base/power/clock_ops.c @@ -0,0 +1,805 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * drivers/base/power/clock_ops.c - Generic clock manipulation PM callbacks + * + * Copyright (c) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp. + */ + +#include <linux/kernel.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/pm.h> +#include <linux/pm_clock.h> +#include <linux/clk.h> +#include <linux/clkdev.h> +#include <linux/of_clk.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/pm_domain.h> +#include <linux/pm_runtime.h> + +#ifdef CONFIG_PM_CLK + +enum pce_status { + PCE_STATUS_NONE = 0, + PCE_STATUS_ACQUIRED, + PCE_STATUS_PREPARED, + PCE_STATUS_ENABLED, + PCE_STATUS_ERROR, +}; + +struct pm_clock_entry { + struct list_head node; + char *con_id; + struct clk *clk; + enum pce_status status; + bool enabled_when_prepared; +}; + +/** + * pm_clk_list_lock - ensure exclusive access for modifying the PM clock + * entry list. + * @psd: pm_subsys_data instance corresponding to the PM clock entry list + * and clk_op_might_sleep count to be modified. + * + * Get exclusive access before modifying the PM clock entry list and the + * clock_op_might_sleep count to guard against concurrent modifications. + * This also protects against a concurrent clock_op_might_sleep and PM clock + * entry list usage in pm_clk_suspend()/pm_clk_resume() that may or may not + * happen in atomic context, hence both the mutex and the spinlock must be + * taken here. + */ +static void pm_clk_list_lock(struct pm_subsys_data *psd) + __acquires(&psd->lock) +{ + mutex_lock(&psd->clock_mutex); + spin_lock_irq(&psd->lock); +} + +/** + * pm_clk_list_unlock - counterpart to pm_clk_list_lock(). + * @psd: the same pm_subsys_data instance previously passed to + * pm_clk_list_lock(). + */ +static void pm_clk_list_unlock(struct pm_subsys_data *psd) + __releases(&psd->lock) +{ + spin_unlock_irq(&psd->lock); + mutex_unlock(&psd->clock_mutex); +} + +/** + * pm_clk_op_lock - ensure exclusive access for performing clock operations. + * @psd: pm_subsys_data instance corresponding to the PM clock entry list + * and clk_op_might_sleep count being used. + * @flags: stored irq flags. + * @fn: string for the caller function's name. + * + * This is used by pm_clk_suspend() and pm_clk_resume() to guard + * against concurrent modifications to the clock entry list and the + * clock_op_might_sleep count. If clock_op_might_sleep is != 0 then + * only the mutex can be locked and those functions can only be used in + * non atomic context. If clock_op_might_sleep == 0 then these functions + * may be used in any context and only the spinlock can be locked. + * Returns -EINVAL if called in atomic context when clock ops might sleep. + */ +static int pm_clk_op_lock(struct pm_subsys_data *psd, unsigned long *flags, + const char *fn) + /* sparse annotations don't work here as exit state isn't static */ +{ + bool atomic_context = in_atomic() || irqs_disabled(); + +try_again: + spin_lock_irqsave(&psd->lock, *flags); + if (!psd->clock_op_might_sleep) { + /* the __release is there to work around sparse limitations */ + __release(&psd->lock); + return 0; + } + + /* bail out if in atomic context */ + if (atomic_context) { + pr_err("%s: atomic context with clock_ops_might_sleep = %d", + fn, psd->clock_op_might_sleep); + spin_unlock_irqrestore(&psd->lock, *flags); + might_sleep(); + return -EPERM; + } + + /* we must switch to the mutex */ + spin_unlock_irqrestore(&psd->lock, *flags); + mutex_lock(&psd->clock_mutex); + + /* + * There was a possibility for psd->clock_op_might_sleep + * to become 0 above. Keep the mutex only if not the case. + */ + if (likely(psd->clock_op_might_sleep)) + return 0; + + mutex_unlock(&psd->clock_mutex); + goto try_again; +} + +/** + * pm_clk_op_unlock - counterpart to pm_clk_op_lock(). + * @psd: the same pm_subsys_data instance previously passed to + * pm_clk_op_lock(). + * @flags: irq flags provided by pm_clk_op_lock(). + */ +static void pm_clk_op_unlock(struct pm_subsys_data *psd, unsigned long *flags) + /* sparse annotations don't work here as entry state isn't static */ +{ + if (psd->clock_op_might_sleep) { + mutex_unlock(&psd->clock_mutex); + } else { + /* the __acquire is there to work around sparse limitations */ + __acquire(&psd->lock); + spin_unlock_irqrestore(&psd->lock, *flags); + } +} + +/** + * __pm_clk_enable - Enable a clock, reporting any errors + * @dev: The device for the given clock + * @ce: PM clock entry corresponding to the clock. + */ +static inline void __pm_clk_enable(struct device *dev, struct pm_clock_entry *ce) +{ + int ret; + + switch (ce->status) { + case PCE_STATUS_ACQUIRED: + ret = clk_prepare_enable(ce->clk); + break; + case PCE_STATUS_PREPARED: + ret = clk_enable(ce->clk); + break; + default: + return; + } + if (!ret) + ce->status = PCE_STATUS_ENABLED; + else + dev_err(dev, "%s: failed to enable clk %p, error %d\n", + __func__, ce->clk, ret); +} + +/** + * pm_clk_acquire - Acquire a device clock. + * @dev: Device whose clock is to be acquired. + * @ce: PM clock entry corresponding to the clock. + */ +static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce) +{ + if (!ce->clk) + ce->clk = clk_get(dev, ce->con_id); + if (IS_ERR(ce->clk)) { + ce->status = PCE_STATUS_ERROR; + return; + } else if (clk_is_enabled_when_prepared(ce->clk)) { + /* we defer preparing the clock in that case */ + ce->status = PCE_STATUS_ACQUIRED; + ce->enabled_when_prepared = true; + } else if (clk_prepare(ce->clk)) { + ce->status = PCE_STATUS_ERROR; + dev_err(dev, "clk_prepare() failed\n"); + return; + } else { + ce->status = PCE_STATUS_PREPARED; + } + dev_dbg(dev, "Clock %pC con_id %s managed by runtime PM.\n", + ce->clk, ce->con_id); +} + +static int __pm_clk_add(struct device *dev, const char *con_id, + struct clk *clk) +{ + struct pm_subsys_data *psd = dev_to_psd(dev); + struct pm_clock_entry *ce; + + if (!psd) + return -EINVAL; + + ce = kzalloc(sizeof(*ce), GFP_KERNEL); + if (!ce) + return -ENOMEM; + + if (con_id) { + ce->con_id = kstrdup(con_id, GFP_KERNEL); + if (!ce->con_id) { + kfree(ce); + return -ENOMEM; + } + } else { + if (IS_ERR(clk)) { + kfree(ce); + return -ENOENT; + } + ce->clk = clk; + } + + pm_clk_acquire(dev, ce); + + pm_clk_list_lock(psd); + list_add_tail(&ce->node, &psd->clock_list); + if (ce->enabled_when_prepared) + psd->clock_op_might_sleep++; + pm_clk_list_unlock(psd); + return 0; +} + +/** + * pm_clk_add - Start using a device clock for power management. + * @dev: Device whose clock is going to be used for power management. + * @con_id: Connection ID of the clock. + * + * Add the clock represented by @con_id to the list of clocks used for + * the power management of @dev. + */ +int pm_clk_add(struct device *dev, const char *con_id) +{ + return __pm_clk_add(dev, con_id, NULL); +} +EXPORT_SYMBOL_GPL(pm_clk_add); + +/** + * pm_clk_add_clk - Start using a device clock for power management. + * @dev: Device whose clock is going to be used for power management. + * @clk: Clock pointer + * + * Add the clock to the list of clocks used for the power management of @dev. + * The power-management code will take control of the clock reference, so + * callers should not call clk_put() on @clk after this function sucessfully + * returned. + */ +int pm_clk_add_clk(struct device *dev, struct clk *clk) +{ + return __pm_clk_add(dev, NULL, clk); +} +EXPORT_SYMBOL_GPL(pm_clk_add_clk); + + +/** + * of_pm_clk_add_clk - Start using a device clock for power management. + * @dev: Device whose clock is going to be used for power management. + * @name: Name of clock that is going to be used for power management. + * + * Add the clock described in the 'clocks' device-tree node that matches + * with the 'name' provided, to the list of clocks used for the power + * management of @dev. On success, returns 0. Returns a negative error + * code if the clock is not found or cannot be added. + */ +int of_pm_clk_add_clk(struct device *dev, const char *name) +{ + struct clk *clk; + int ret; + + if (!dev || !dev->of_node || !name) + return -EINVAL; + + clk = of_clk_get_by_name(dev->of_node, name); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + ret = pm_clk_add_clk(dev, clk); + if (ret) { + clk_put(clk); + return ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(of_pm_clk_add_clk); + +/** + * of_pm_clk_add_clks - Start using device clock(s) for power management. + * @dev: Device whose clock(s) is going to be used for power management. + * + * Add a series of clocks described in the 'clocks' device-tree node for + * a device to the list of clocks used for the power management of @dev. + * On success, returns the number of clocks added. Returns a negative + * error code if there are no clocks in the device node for the device + * or if adding a clock fails. + */ +int of_pm_clk_add_clks(struct device *dev) +{ + struct clk **clks; + int i, count; + int ret; + + if (!dev || !dev->of_node) + return -EINVAL; + + count = of_clk_get_parent_count(dev->of_node); + if (count <= 0) + return -ENODEV; + + clks = kcalloc(count, sizeof(*clks), GFP_KERNEL); + if (!clks) + return -ENOMEM; + + for (i = 0; i < count; i++) { + clks[i] = of_clk_get(dev->of_node, i); + if (IS_ERR(clks[i])) { + ret = PTR_ERR(clks[i]); + goto error; + } + + ret = pm_clk_add_clk(dev, clks[i]); + if (ret) { + clk_put(clks[i]); + goto error; + } + } + + kfree(clks); + + return i; + +error: + while (i--) + pm_clk_remove_clk(dev, clks[i]); + + kfree(clks); + + return ret; +} +EXPORT_SYMBOL_GPL(of_pm_clk_add_clks); + +/** + * __pm_clk_remove - Destroy PM clock entry. + * @ce: PM clock entry to destroy. + */ +static void __pm_clk_remove(struct pm_clock_entry *ce) +{ + if (!ce) + return; + + switch (ce->status) { + case PCE_STATUS_ENABLED: + clk_disable(ce->clk); + fallthrough; + case PCE_STATUS_PREPARED: + clk_unprepare(ce->clk); + fallthrough; + case PCE_STATUS_ACQUIRED: + case PCE_STATUS_ERROR: + if (!IS_ERR(ce->clk)) + clk_put(ce->clk); + break; + default: + break; + } + + kfree(ce->con_id); + kfree(ce); +} + +/** + * pm_clk_remove - Stop using a device clock for power management. + * @dev: Device whose clock should not be used for PM any more. + * @con_id: Connection ID of the clock. + * + * Remove the clock represented by @con_id from the list of clocks used for + * the power management of @dev. + */ +void pm_clk_remove(struct device *dev, const char *con_id) +{ + struct pm_subsys_data *psd = dev_to_psd(dev); + struct pm_clock_entry *ce; + + if (!psd) + return; + + pm_clk_list_lock(psd); + + list_for_each_entry(ce, &psd->clock_list, node) { + if (!con_id && !ce->con_id) + goto remove; + else if (!con_id || !ce->con_id) + continue; + else if (!strcmp(con_id, ce->con_id)) + goto remove; + } + + pm_clk_list_unlock(psd); + return; + + remove: + list_del(&ce->node); + if (ce->enabled_when_prepared) + psd->clock_op_might_sleep--; + pm_clk_list_unlock(psd); + + __pm_clk_remove(ce); +} +EXPORT_SYMBOL_GPL(pm_clk_remove); + +/** + * pm_clk_remove_clk - Stop using a device clock for power management. + * @dev: Device whose clock should not be used for PM any more. + * @clk: Clock pointer + * + * Remove the clock pointed to by @clk from the list of clocks used for + * the power management of @dev. + */ +void pm_clk_remove_clk(struct device *dev, struct clk *clk) +{ + struct pm_subsys_data *psd = dev_to_psd(dev); + struct pm_clock_entry *ce; + + if (!psd || !clk) + return; + + pm_clk_list_lock(psd); + + list_for_each_entry(ce, &psd->clock_list, node) { + if (clk == ce->clk) + goto remove; + } + + pm_clk_list_unlock(psd); + return; + + remove: + list_del(&ce->node); + if (ce->enabled_when_prepared) + psd->clock_op_might_sleep--; + pm_clk_list_unlock(psd); + + __pm_clk_remove(ce); +} +EXPORT_SYMBOL_GPL(pm_clk_remove_clk); + +/** + * pm_clk_init - Initialize a device's list of power management clocks. + * @dev: Device to initialize the list of PM clocks for. + * + * Initialize the lock and clock_list members of the device's pm_subsys_data + * object, set the count of clocks that might sleep to 0. + */ +void pm_clk_init(struct device *dev) +{ + struct pm_subsys_data *psd = dev_to_psd(dev); + if (psd) { + INIT_LIST_HEAD(&psd->clock_list); + mutex_init(&psd->clock_mutex); + psd->clock_op_might_sleep = 0; + } +} +EXPORT_SYMBOL_GPL(pm_clk_init); + +/** + * pm_clk_create - Create and initialize a device's list of PM clocks. + * @dev: Device to create and initialize the list of PM clocks for. + * + * Allocate a struct pm_subsys_data object, initialize its lock and clock_list + * members and make the @dev's power.subsys_data field point to it. + */ +int pm_clk_create(struct device *dev) +{ + return dev_pm_get_subsys_data(dev); +} +EXPORT_SYMBOL_GPL(pm_clk_create); + +/** + * pm_clk_destroy - Destroy a device's list of power management clocks. + * @dev: Device to destroy the list of PM clocks for. + * + * Clear the @dev's power.subsys_data field, remove the list of clock entries + * from the struct pm_subsys_data object pointed to by it before and free + * that object. + */ +void pm_clk_destroy(struct device *dev) +{ + struct pm_subsys_data *psd = dev_to_psd(dev); + struct pm_clock_entry *ce, *c; + struct list_head list; + + if (!psd) + return; + + INIT_LIST_HEAD(&list); + + pm_clk_list_lock(psd); + + list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node) + list_move(&ce->node, &list); + psd->clock_op_might_sleep = 0; + + pm_clk_list_unlock(psd); + + dev_pm_put_subsys_data(dev); + + list_for_each_entry_safe_reverse(ce, c, &list, node) { + list_del(&ce->node); + __pm_clk_remove(ce); + } +} +EXPORT_SYMBOL_GPL(pm_clk_destroy); + +static void pm_clk_destroy_action(void *data) +{ + pm_clk_destroy(data); +} + +int devm_pm_clk_create(struct device *dev) +{ + int ret; + + ret = pm_clk_create(dev); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, pm_clk_destroy_action, dev); +} +EXPORT_SYMBOL_GPL(devm_pm_clk_create); + +/** + * pm_clk_suspend - Disable clocks in a device's PM clock list. + * @dev: Device to disable the clocks for. + */ +int pm_clk_suspend(struct device *dev) +{ + struct pm_subsys_data *psd = dev_to_psd(dev); + struct pm_clock_entry *ce; + unsigned long flags; + int ret; + + dev_dbg(dev, "%s()\n", __func__); + + if (!psd) + return 0; + + ret = pm_clk_op_lock(psd, &flags, __func__); + if (ret) + return ret; + + list_for_each_entry_reverse(ce, &psd->clock_list, node) { + if (ce->status == PCE_STATUS_ENABLED) { + if (ce->enabled_when_prepared) { + clk_disable_unprepare(ce->clk); + ce->status = PCE_STATUS_ACQUIRED; + } else { + clk_disable(ce->clk); + ce->status = PCE_STATUS_PREPARED; + } + } + } + + pm_clk_op_unlock(psd, &flags); + + return 0; +} +EXPORT_SYMBOL_GPL(pm_clk_suspend); + +/** + * pm_clk_resume - Enable clocks in a device's PM clock list. + * @dev: Device to enable the clocks for. + */ +int pm_clk_resume(struct device *dev) +{ + struct pm_subsys_data *psd = dev_to_psd(dev); + struct pm_clock_entry *ce; + unsigned long flags; + int ret; + + dev_dbg(dev, "%s()\n", __func__); + + if (!psd) + return 0; + + ret = pm_clk_op_lock(psd, &flags, __func__); + if (ret) + return ret; + + list_for_each_entry(ce, &psd->clock_list, node) + __pm_clk_enable(dev, ce); + + pm_clk_op_unlock(psd, &flags); + + return 0; +} +EXPORT_SYMBOL_GPL(pm_clk_resume); + +/** + * pm_clk_notify - Notify routine for device addition and removal. + * @nb: Notifier block object this function is a member of. + * @action: Operation being carried out by the caller. + * @data: Device the routine is being run for. + * + * For this function to work, @nb must be a member of an object of type + * struct pm_clk_notifier_block containing all of the requisite data. + * Specifically, the pm_domain member of that object is copied to the device's + * pm_domain field and its con_ids member is used to populate the device's list + * of PM clocks, depending on @action. + * + * If the device's pm_domain field is already populated with a value different + * from the one stored in the struct pm_clk_notifier_block object, the function + * does nothing. + */ +static int pm_clk_notify(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct pm_clk_notifier_block *clknb; + struct device *dev = data; + char **con_id; + int error; + + dev_dbg(dev, "%s() %ld\n", __func__, action); + + clknb = container_of(nb, struct pm_clk_notifier_block, nb); + + switch (action) { + case BUS_NOTIFY_ADD_DEVICE: + if (dev->pm_domain) + break; + + error = pm_clk_create(dev); + if (error) + break; + + dev_pm_domain_set(dev, clknb->pm_domain); + if (clknb->con_ids[0]) { + for (con_id = clknb->con_ids; *con_id; con_id++) + pm_clk_add(dev, *con_id); + } else { + pm_clk_add(dev, NULL); + } + + break; + case BUS_NOTIFY_DEL_DEVICE: + if (dev->pm_domain != clknb->pm_domain) + break; + + dev_pm_domain_set(dev, NULL); + pm_clk_destroy(dev); + break; + } + + return 0; +} + +int pm_clk_runtime_suspend(struct device *dev) +{ + int ret; + + dev_dbg(dev, "%s\n", __func__); + + ret = pm_generic_runtime_suspend(dev); + if (ret) { + dev_err(dev, "failed to suspend device\n"); + return ret; + } + + ret = pm_clk_suspend(dev); + if (ret) { + dev_err(dev, "failed to suspend clock\n"); + pm_generic_runtime_resume(dev); + return ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(pm_clk_runtime_suspend); + +int pm_clk_runtime_resume(struct device *dev) +{ + int ret; + + dev_dbg(dev, "%s\n", __func__); + + ret = pm_clk_resume(dev); + if (ret) { + dev_err(dev, "failed to resume clock\n"); + return ret; + } + + return pm_generic_runtime_resume(dev); +} +EXPORT_SYMBOL_GPL(pm_clk_runtime_resume); + +#else /* !CONFIG_PM_CLK */ + +/** + * enable_clock - Enable a device clock. + * @dev: Device whose clock is to be enabled. + * @con_id: Connection ID of the clock. + */ +static void enable_clock(struct device *dev, const char *con_id) +{ + struct clk *clk; + + clk = clk_get(dev, con_id); + if (!IS_ERR(clk)) { + clk_prepare_enable(clk); + clk_put(clk); + dev_info(dev, "Runtime PM disabled, clock forced on.\n"); + } +} + +/** + * disable_clock - Disable a device clock. + * @dev: Device whose clock is to be disabled. + * @con_id: Connection ID of the clock. + */ +static void disable_clock(struct device *dev, const char *con_id) +{ + struct clk *clk; + + clk = clk_get(dev, con_id); + if (!IS_ERR(clk)) { + clk_disable_unprepare(clk); + clk_put(clk); + dev_info(dev, "Runtime PM disabled, clock forced off.\n"); + } +} + +/** + * pm_clk_notify - Notify routine for device addition and removal. + * @nb: Notifier block object this function is a member of. + * @action: Operation being carried out by the caller. + * @data: Device the routine is being run for. + * + * For this function to work, @nb must be a member of an object of type + * struct pm_clk_notifier_block containing all of the requisite data. + * Specifically, the con_ids member of that object is used to enable or disable + * the device's clocks, depending on @action. + */ +static int pm_clk_notify(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct pm_clk_notifier_block *clknb; + struct device *dev = data; + char **con_id; + + dev_dbg(dev, "%s() %ld\n", __func__, action); + + clknb = container_of(nb, struct pm_clk_notifier_block, nb); + + switch (action) { + case BUS_NOTIFY_BIND_DRIVER: + if (clknb->con_ids[0]) { + for (con_id = clknb->con_ids; *con_id; con_id++) + enable_clock(dev, *con_id); + } else { + enable_clock(dev, NULL); + } + break; + case BUS_NOTIFY_DRIVER_NOT_BOUND: + case BUS_NOTIFY_UNBOUND_DRIVER: + if (clknb->con_ids[0]) { + for (con_id = clknb->con_ids; *con_id; con_id++) + disable_clock(dev, *con_id); + } else { + disable_clock(dev, NULL); + } + break; + } + + return 0; +} + +#endif /* !CONFIG_PM_CLK */ + +/** + * pm_clk_add_notifier - Add bus type notifier for power management clocks. + * @bus: Bus type to add the notifier to. + * @clknb: Notifier to be added to the given bus type. + * + * The nb member of @clknb is not expected to be initialized and its + * notifier_call member will be replaced with pm_clk_notify(). However, + * the remaining members of @clknb should be populated prior to calling this + * routine. + */ +void pm_clk_add_notifier(struct bus_type *bus, + struct pm_clk_notifier_block *clknb) +{ + if (!bus || !clknb) + return; + + clknb->nb.notifier_call = pm_clk_notify; + bus_register_notifier(bus, &clknb->nb); +} +EXPORT_SYMBOL_GPL(pm_clk_add_notifier); |