diff --git a/drivers/reset/core.c b/drivers/reset/core.c index f15f150b79da..72b32bd15549 100644 --- a/drivers/reset/core.c +++ b/drivers/reset/core.c @@ -8,6 +8,7 @@ * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ +#include #include #include #include @@ -18,19 +19,27 @@ #include #include -static DEFINE_MUTEX(reset_controller_list_mutex); +static DEFINE_MUTEX(reset_list_mutex); static LIST_HEAD(reset_controller_list); /** * struct reset_control - a reset control * @rcdev: a pointer to the reset controller device * this reset control belongs to + * @list: list entry for the rcdev's reset controller list * @id: ID of the reset controller in the reset * controller device + * @refcnt: Number of gets of this reset_control + * @shared: Is this a shared (1), or an exclusive (0) reset_control? + * @deassert_cnt: Number of times this reset line has been deasserted */ struct reset_control { struct reset_controller_dev *rcdev; + struct list_head list; unsigned int id; + unsigned int refcnt; + int shared; + atomic_t deassert_count; }; /** @@ -62,9 +71,11 @@ int reset_controller_register(struct reset_controller_dev *rcdev) rcdev->of_xlate = of_reset_simple_xlate; } - mutex_lock(&reset_controller_list_mutex); + INIT_LIST_HEAD(&rcdev->reset_control_head); + + mutex_lock(&reset_list_mutex); list_add(&rcdev->list, &reset_controller_list); - mutex_unlock(&reset_controller_list_mutex); + mutex_unlock(&reset_list_mutex); return 0; } @@ -76,18 +87,23 @@ EXPORT_SYMBOL_GPL(reset_controller_register); */ void reset_controller_unregister(struct reset_controller_dev *rcdev) { - mutex_lock(&reset_controller_list_mutex); + mutex_lock(&reset_list_mutex); list_del(&rcdev->list); - mutex_unlock(&reset_controller_list_mutex); + mutex_unlock(&reset_list_mutex); } EXPORT_SYMBOL_GPL(reset_controller_unregister); /** * reset_control_reset - reset the controlled device * @rstc: reset controller + * + * Calling this on a shared reset controller is an error. */ int reset_control_reset(struct reset_control *rstc) { + if (WARN_ON(rstc->shared)) + return -EINVAL; + if (rstc->rcdev->ops->reset) return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); @@ -98,26 +114,48 @@ EXPORT_SYMBOL_GPL(reset_control_reset); /** * reset_control_assert - asserts the reset line * @rstc: reset controller + * + * Calling this on an exclusive reset controller guarantees that the reset + * will be asserted. When called on a shared reset controller the line may + * still be deasserted, as long as other users keep it so. + * + * For shared reset controls a driver cannot expect the hw's registers and + * internal state to be reset, but must be prepared for this to happen. */ int reset_control_assert(struct reset_control *rstc) { - if (rstc->rcdev->ops->assert) - return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); + if (!rstc->rcdev->ops->assert) + return -ENOTSUPP; - return -ENOTSUPP; + if (rstc->shared) { + if (WARN_ON(atomic_read(&rstc->deassert_count) == 0)) + return -EINVAL; + + if (atomic_dec_return(&rstc->deassert_count) != 0) + return 0; + } + + return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); } EXPORT_SYMBOL_GPL(reset_control_assert); /** * reset_control_deassert - deasserts the reset line * @rstc: reset controller + * + * After calling this function, the reset is guaranteed to be deasserted. */ int reset_control_deassert(struct reset_control *rstc) { - if (rstc->rcdev->ops->deassert) - return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); + if (!rstc->rcdev->ops->deassert) + return -ENOTSUPP; - return -ENOTSUPP; + if (rstc->shared) { + if (atomic_inc_return(&rstc->deassert_count) != 1) + return 0; + } + + return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); } EXPORT_SYMBOL_GPL(reset_control_deassert); @@ -136,18 +174,54 @@ int reset_control_status(struct reset_control *rstc) } EXPORT_SYMBOL_GPL(reset_control_status); -/** - * of_reset_control_get_by_index - Lookup and obtain a reference to a reset - * controller by index. - * @node: device to be reset by the controller - * @index: index of the reset controller - * - * This is to be used to perform a list of resets for a device or power domain - * in whatever order. Returns a struct reset_control or IS_ERR() condition - * containing errno. - */ -struct reset_control *of_reset_control_get_by_index(struct device_node *node, - int index) +static struct reset_control *__reset_control_get( + struct reset_controller_dev *rcdev, + unsigned int index, int shared) +{ + struct reset_control *rstc; + + lockdep_assert_held(&reset_list_mutex); + + list_for_each_entry(rstc, &rcdev->reset_control_head, list) { + if (rstc->id == index) { + if (WARN_ON(!rstc->shared || !shared)) + return ERR_PTR(-EBUSY); + + rstc->refcnt++; + return rstc; + } + } + + rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); + if (!rstc) + return ERR_PTR(-ENOMEM); + + try_module_get(rcdev->owner); + + rstc->rcdev = rcdev; + list_add(&rstc->list, &rcdev->reset_control_head); + rstc->id = index; + rstc->refcnt = 1; + rstc->shared = shared; + + return rstc; +} + +static void __reset_control_put(struct reset_control *rstc) +{ + lockdep_assert_held(&reset_list_mutex); + + if (--rstc->refcnt) + return; + + module_put(rstc->rcdev->owner); + + list_del(&rstc->list); + kfree(rstc); +} + +struct reset_control *__of_reset_control_get(struct device_node *node, + const char *id, int index, int shared) { struct reset_control *rstc; struct reset_controller_dev *r, *rcdev; @@ -155,12 +229,22 @@ struct reset_control *of_reset_control_get_by_index(struct device_node *node, int rstc_id; int ret; + if (!node) + return ERR_PTR(-EINVAL); + + if (id) { + index = of_property_match_string(node, + "reset-names", id); + if (index < 0) + return ERR_PTR(-ENOENT); + } + ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", index, &args); if (ret) return ERR_PTR(ret); - mutex_lock(&reset_controller_list_mutex); + mutex_lock(&reset_list_mutex); rcdev = NULL; list_for_each_entry(r, &reset_controller_list, list) { if (args.np == r->of_node) { @@ -171,78 +255,29 @@ struct reset_control *of_reset_control_get_by_index(struct device_node *node, of_node_put(args.np); if (!rcdev) { - mutex_unlock(&reset_controller_list_mutex); + mutex_unlock(&reset_list_mutex); return ERR_PTR(-EPROBE_DEFER); } if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) { - mutex_unlock(&reset_controller_list_mutex); + mutex_unlock(&reset_list_mutex); return ERR_PTR(-EINVAL); } rstc_id = rcdev->of_xlate(rcdev, &args); if (rstc_id < 0) { - mutex_unlock(&reset_controller_list_mutex); + mutex_unlock(&reset_list_mutex); return ERR_PTR(rstc_id); } - try_module_get(rcdev->owner); - mutex_unlock(&reset_controller_list_mutex); + /* reset_list_mutex also protects the rcdev's reset_control list */ + rstc = __reset_control_get(rcdev, rstc_id, shared); - rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); - if (!rstc) { - module_put(rcdev->owner); - return ERR_PTR(-ENOMEM); - } - - rstc->rcdev = rcdev; - rstc->id = rstc_id; + mutex_unlock(&reset_list_mutex); return rstc; } -EXPORT_SYMBOL_GPL(of_reset_control_get_by_index); - -/** - * of_reset_control_get - Lookup and obtain a reference to a reset controller. - * @node: device to be reset by the controller - * @id: reset line name - * - * Returns a struct reset_control or IS_ERR() condition containing errno. - * - * Use of id names is optional. - */ -struct reset_control *of_reset_control_get(struct device_node *node, - const char *id) -{ - int index = 0; - - if (id) { - index = of_property_match_string(node, - "reset-names", id); - if (index < 0) - return ERR_PTR(-ENOENT); - } - return of_reset_control_get_by_index(node, index); -} -EXPORT_SYMBOL_GPL(of_reset_control_get); - -/** - * reset_control_get - Lookup and obtain a reference to a reset controller. - * @dev: device to be reset by the controller - * @id: reset line name - * - * Returns a struct reset_control or IS_ERR() condition containing errno. - * - * Use of id names is optional. - */ -struct reset_control *reset_control_get(struct device *dev, const char *id) -{ - if (!dev) - return ERR_PTR(-EINVAL); - - return of_reset_control_get(dev->of_node, id); -} -EXPORT_SYMBOL_GPL(reset_control_get); +EXPORT_SYMBOL_GPL(__of_reset_control_get); /** * reset_control_put - free the reset controller @@ -254,8 +289,9 @@ void reset_control_put(struct reset_control *rstc) if (IS_ERR(rstc)) return; - module_put(rstc->rcdev->owner); - kfree(rstc); + mutex_lock(&reset_list_mutex); + __reset_control_put(rstc); + mutex_unlock(&reset_list_mutex); } EXPORT_SYMBOL_GPL(reset_control_put); @@ -264,16 +300,8 @@ static void devm_reset_control_release(struct device *dev, void *res) reset_control_put(*(struct reset_control **)res); } -/** - * devm_reset_control_get - resource managed reset_control_get() - * @dev: device to be reset by the controller - * @id: reset line name - * - * Managed reset_control_get(). For reset controllers returned from this - * function, reset_control_put() is called automatically on driver detach. - * See reset_control_get() for more information. - */ -struct reset_control *devm_reset_control_get(struct device *dev, const char *id) +struct reset_control *__devm_reset_control_get(struct device *dev, + const char *id, int index, int shared) { struct reset_control **ptr, *rstc; @@ -282,7 +310,8 @@ struct reset_control *devm_reset_control_get(struct device *dev, const char *id) if (!ptr) return ERR_PTR(-ENOMEM); - rstc = reset_control_get(dev, id); + rstc = __of_reset_control_get(dev ? dev->of_node : NULL, + id, index, shared); if (!IS_ERR(rstc)) { *ptr = rstc; devres_add(dev, ptr); @@ -292,7 +321,7 @@ struct reset_control *devm_reset_control_get(struct device *dev, const char *id) return rstc; } -EXPORT_SYMBOL_GPL(devm_reset_control_get); +EXPORT_SYMBOL_GPL(__devm_reset_control_get); /** * device_reset - find reset controller associated with the device diff --git a/drivers/reset/reset-lpc18xx.c b/drivers/reset/reset-lpc18xx.c index 3b8a4f5a1ff6..54cca0055171 100644 --- a/drivers/reset/reset-lpc18xx.c +++ b/drivers/reset/reset-lpc18xx.c @@ -35,6 +35,7 @@ struct lpc18xx_rgu_data { struct reset_controller_dev rcdev; + struct notifier_block restart_nb; struct clk *clk_delay; struct clk *clk_reg; void __iomem *base; @@ -44,12 +45,13 @@ struct lpc18xx_rgu_data { #define to_rgu_data(p) container_of(p, struct lpc18xx_rgu_data, rcdev) -static void __iomem *rgu_base; - -static int lpc18xx_rgu_restart(struct notifier_block *this, unsigned long mode, +static int lpc18xx_rgu_restart(struct notifier_block *nb, unsigned long mode, void *cmd) { - writel(BIT(LPC18XX_RGU_CORE_RST), rgu_base + LPC18XX_RGU_CTRL0); + struct lpc18xx_rgu_data *rc = container_of(nb, struct lpc18xx_rgu_data, + restart_nb); + + writel(BIT(LPC18XX_RGU_CORE_RST), rc->base + LPC18XX_RGU_CTRL0); mdelay(2000); pr_emerg("%s: unable to restart system\n", __func__); @@ -57,11 +59,6 @@ static int lpc18xx_rgu_restart(struct notifier_block *this, unsigned long mode, return NOTIFY_DONE; } -static struct notifier_block lpc18xx_rgu_restart_nb = { - .notifier_call = lpc18xx_rgu_restart, - .priority = 192, -}; - /* * The LPC18xx RGU has mostly self-deasserting resets except for the * two reset lines going to the internal Cortex-M0 cores. @@ -205,8 +202,9 @@ static int lpc18xx_rgu_probe(struct platform_device *pdev) goto dis_clks; } - rgu_base = rc->base; - ret = register_restart_handler(&lpc18xx_rgu_restart_nb); + rc->restart_nb.priority = 192, + rc->restart_nb.notifier_call = lpc18xx_rgu_restart, + ret = register_restart_handler(&rc->restart_nb); if (ret) dev_warn(&pdev->dev, "failed to register restart handler\n"); @@ -225,7 +223,7 @@ static int lpc18xx_rgu_remove(struct platform_device *pdev) struct lpc18xx_rgu_data *rc = platform_get_drvdata(pdev); int ret; - ret = unregister_restart_handler(&lpc18xx_rgu_restart_nb); + ret = unregister_restart_handler(&rc->restart_nb); if (ret) dev_warn(&pdev->dev, "failed to unregister restart handler\n"); diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h index a3a5bcdb1d02..b91ba932bbd4 100644 --- a/include/linux/reset-controller.h +++ b/include/linux/reset-controller.h @@ -31,6 +31,7 @@ struct of_phandle_args; * @ops: a pointer to device specific struct reset_control_ops * @owner: kernel module of the reset controller driver * @list: internal list of reset controller devices + * @reset_control_head: head of internal list of requested reset controls * @of_node: corresponding device tree node as phandle target * @of_reset_n_cells: number of cells in reset line specifiers * @of_xlate: translation function to translate from specifier as found in the @@ -41,6 +42,7 @@ struct reset_controller_dev { const struct reset_control_ops *ops; struct module *owner; struct list_head list; + struct list_head reset_control_head; struct device_node *of_node; int of_reset_n_cells; int (*of_xlate)(struct reset_controller_dev *rcdev, diff --git a/include/linux/reset.h b/include/linux/reset.h index c4c097de0ba9..a552134a209e 100644 --- a/include/linux/reset.h +++ b/include/linux/reset.h @@ -1,8 +1,8 @@ #ifndef _LINUX_RESET_H_ #define _LINUX_RESET_H_ -struct device; -struct device_node; +#include + struct reset_control; #ifdef CONFIG_RESET_CONTROLLER @@ -12,9 +12,11 @@ int reset_control_assert(struct reset_control *rstc); int reset_control_deassert(struct reset_control *rstc); int reset_control_status(struct reset_control *rstc); -struct reset_control *reset_control_get(struct device *dev, const char *id); +struct reset_control *__of_reset_control_get(struct device_node *node, + const char *id, int index, int shared); void reset_control_put(struct reset_control *rstc); -struct reset_control *devm_reset_control_get(struct device *dev, const char *id); +struct reset_control *__devm_reset_control_get(struct device *dev, + const char *id, int index, int shared); int __must_check device_reset(struct device *dev); @@ -23,24 +25,6 @@ static inline int device_reset_optional(struct device *dev) return device_reset(dev); } -static inline struct reset_control *reset_control_get_optional( - struct device *dev, const char *id) -{ - return reset_control_get(dev, id); -} - -static inline struct reset_control *devm_reset_control_get_optional( - struct device *dev, const char *id) -{ - return devm_reset_control_get(dev, id); -} - -struct reset_control *of_reset_control_get(struct device_node *node, - const char *id); - -struct reset_control *of_reset_control_get_by_index( - struct device_node *node, int index); - #else static inline int reset_control_reset(struct reset_control *rstc) @@ -77,44 +61,180 @@ static inline int device_reset_optional(struct device *dev) return -ENOTSUPP; } -static inline struct reset_control *__must_check reset_control_get( - struct device *dev, const char *id) +static inline struct reset_control *__of_reset_control_get( + struct device_node *node, + const char *id, int index, int shared) { - WARN_ON(1); return ERR_PTR(-EINVAL); } -static inline struct reset_control *__must_check devm_reset_control_get( +static inline struct reset_control *__devm_reset_control_get( + struct device *dev, + const char *id, int index, int shared) +{ + return ERR_PTR(-EINVAL); +} + +#endif /* CONFIG_RESET_CONTROLLER */ + +/** + * reset_control_get - Lookup and obtain an exclusive reference to a + * reset controller. + * @dev: device to be reset by the controller + * @id: reset line name + * + * Returns a struct reset_control or IS_ERR() condition containing errno. + * If this function is called more then once for the same reset_control it will + * return -EBUSY. + * + * See reset_control_get_shared for details on shared references to + * reset-controls. + * + * Use of id names is optional. + */ +static inline struct reset_control *__must_check reset_control_get( struct device *dev, const char *id) { +#ifndef CONFIG_RESET_CONTROLLER WARN_ON(1); - return ERR_PTR(-EINVAL); +#endif + return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0); } static inline struct reset_control *reset_control_get_optional( struct device *dev, const char *id) { - return ERR_PTR(-ENOTSUPP); + return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0); +} + +/** + * reset_control_get_shared - Lookup and obtain a shared reference to a + * reset controller. + * @dev: device to be reset by the controller + * @id: reset line name + * + * Returns a struct reset_control or IS_ERR() condition containing errno. + * This function is intended for use with reset-controls which are shared + * between hardware-blocks. + * + * When a reset-control is shared, the behavior of reset_control_assert / + * deassert is changed, the reset-core will keep track of a deassert_count + * and only (re-)assert the reset after reset_control_assert has been called + * as many times as reset_control_deassert was called. Also see the remark + * about shared reset-controls in the reset_control_assert docs. + * + * Calling reset_control_assert without first calling reset_control_deassert + * is not allowed on a shared reset control. Calling reset_control_reset is + * also not allowed on a shared reset control. + * + * Use of id names is optional. + */ +static inline struct reset_control *reset_control_get_shared( + struct device *dev, const char *id) +{ + return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 1); +} + +/** + * of_reset_control_get - Lookup and obtain an exclusive reference to a + * reset controller. + * @node: device to be reset by the controller + * @id: reset line name + * + * Returns a struct reset_control or IS_ERR() condition containing errno. + * + * Use of id names is optional. + */ +static inline struct reset_control *of_reset_control_get( + struct device_node *node, const char *id) +{ + return __of_reset_control_get(node, id, 0, 0); +} + +/** + * of_reset_control_get_by_index - Lookup and obtain an exclusive reference to + * a reset controller by index. + * @node: device to be reset by the controller + * @index: index of the reset controller + * + * This is to be used to perform a list of resets for a device or power domain + * in whatever order. Returns a struct reset_control or IS_ERR() condition + * containing errno. + */ +static inline struct reset_control *of_reset_control_get_by_index( + struct device_node *node, int index) +{ + return __of_reset_control_get(node, NULL, index, 0); +} + +/** + * devm_reset_control_get - resource managed reset_control_get() + * @dev: device to be reset by the controller + * @id: reset line name + * + * Managed reset_control_get(). For reset controllers returned from this + * function, reset_control_put() is called automatically on driver detach. + * See reset_control_get() for more information. + */ +static inline struct reset_control *__must_check devm_reset_control_get( + struct device *dev, const char *id) +{ +#ifndef CONFIG_RESET_CONTROLLER + WARN_ON(1); +#endif + return __devm_reset_control_get(dev, id, 0, 0); } static inline struct reset_control *devm_reset_control_get_optional( struct device *dev, const char *id) { - return ERR_PTR(-ENOTSUPP); + return __devm_reset_control_get(dev, id, 0, 0); } -static inline struct reset_control *of_reset_control_get( - struct device_node *node, const char *id) +/** + * devm_reset_control_get_by_index - resource managed reset_control_get + * @dev: device to be reset by the controller + * @index: index of the reset controller + * + * Managed reset_control_get(). For reset controllers returned from this + * function, reset_control_put() is called automatically on driver detach. + * See reset_control_get() for more information. + */ +static inline struct reset_control *devm_reset_control_get_by_index( + struct device *dev, int index) { - return ERR_PTR(-ENOTSUPP); + return __devm_reset_control_get(dev, NULL, index, 0); } -static inline struct reset_control *of_reset_control_get_by_index( - struct device_node *node, int index) +/** + * devm_reset_control_get_shared - resource managed reset_control_get_shared() + * @dev: device to be reset by the controller + * @id: reset line name + * + * Managed reset_control_get_shared(). For reset controllers returned from + * this function, reset_control_put() is called automatically on driver detach. + * See reset_control_get_shared() for more information. + */ +static inline struct reset_control *devm_reset_control_get_shared( + struct device *dev, const char *id) { - return ERR_PTR(-ENOTSUPP); + return __devm_reset_control_get(dev, id, 0, 1); } -#endif /* CONFIG_RESET_CONTROLLER */ +/** + * devm_reset_control_get_shared_by_index - resource managed + * reset_control_get_shared + * @dev: device to be reset by the controller + * @index: index of the reset controller + * + * Managed reset_control_get_shared(). For reset controllers returned from + * this function, reset_control_put() is called automatically on driver detach. + * See reset_control_get_shared() for more information. + */ +static inline struct reset_control *devm_reset_control_get_shared_by_index( + struct device *dev, int index) +{ + return __devm_reset_control_get(dev, NULL, index, 1); +} #endif