From 6c96f05c8bb8bc4177613ef3c23a56b455e75887 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 23 Feb 2016 18:46:24 +0100 Subject: reset: Make [of_]reset_control_get[_foo] functions wrappers With both the regular, _by_index and _optional variants we already have quite a few variants of [of_]reset_control_get[_foo], the upcoming addition of shared reset lines support makes this worse. This commit changes all the variants into wrappers around common core functions. For completeness sake this commit also adds a new devm_get_reset_control_by_index wrapper. Signed-off-by: Hans de Goede Signed-off-by: Philipp Zabel --- drivers/reset/core.c | 84 +++++++++++----------------------------------------- 1 file changed, 17 insertions(+), 67 deletions(-) (limited to 'drivers/reset/core.c') diff --git a/drivers/reset/core.c b/drivers/reset/core.c index f15f150b79da..bdf1763da87a 100644 --- a/drivers/reset/core.c +++ b/drivers/reset/core.c @@ -136,18 +136,8 @@ 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) +struct reset_control *__of_reset_control_get(struct device_node *node, + const char *id, int index) { struct reset_control *rstc; struct reset_controller_dev *r, *rcdev; @@ -155,6 +145,16 @@ 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) @@ -200,49 +200,7 @@ struct reset_control *of_reset_control_get_by_index(struct device_node *node, 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 @@ -264,16 +222,8 @@ 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) { struct reset_control **ptr, *rstc; @@ -282,7 +232,7 @@ 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); if (!IS_ERR(rstc)) { *ptr = rstc; devres_add(dev, ptr); @@ -292,7 +242,7 @@ 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 -- cgit v1.2.3 From c15ddec2ca06076a11195313aa1fce47d2a28c5d Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 23 Feb 2016 18:46:25 +0100 Subject: reset: Share struct reset_control between reset_control_get calls Now that struct reset_control no longer stores the device pointer for the device calling reset_control_get we can share a single struct reset_control when multiple calls to reset_control_get are made for the same reset line (same id / index). This is a preparation patch for adding support for shared reset lines. Signed-off-by: Hans de Goede Signed-off-by: Philipp Zabel --- drivers/reset/core.c | 84 ++++++++++++++++++++++++++++++---------- include/linux/reset-controller.h | 2 + 2 files changed, 65 insertions(+), 21 deletions(-) (limited to 'drivers/reset/core.c') diff --git a/drivers/reset/core.c b/drivers/reset/core.c index bdf1763da87a..957750600ff3 100644 --- a/drivers/reset/core.c +++ b/drivers/reset/core.c @@ -18,19 +18,23 @@ #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 */ struct reset_control { struct reset_controller_dev *rcdev; + struct list_head list; unsigned int id; + unsigned int refcnt; }; /** @@ -62,9 +66,11 @@ 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; } @@ -76,9 +82,9 @@ 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); @@ -136,6 +142,48 @@ int reset_control_status(struct reset_control *rstc) } EXPORT_SYMBOL_GPL(reset_control_status); +static struct reset_control *__reset_control_get( + struct reset_controller_dev *rcdev, + unsigned int index) +{ + struct reset_control *rstc; + + lockdep_assert_held(&reset_list_mutex); + + list_for_each_entry(rstc, &rcdev->reset_control_head, list) { + if (rstc->id == index) { + 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; + + 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) { @@ -160,7 +208,7 @@ struct reset_control *__of_reset_control_get(struct device_node *node, 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) { @@ -171,32 +219,25 @@ struct reset_control *__of_reset_control_get(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); - - rstc = kzalloc(sizeof(*rstc), GFP_KERNEL); - if (!rstc) { - module_put(rcdev->owner); - return ERR_PTR(-ENOMEM); - } + /* reset_list_mutex also protects the rcdev's reset_control list */ + rstc = __reset_control_get(rcdev, rstc_id); - rstc->rcdev = rcdev; - rstc->id = rstc_id; + mutex_unlock(&reset_list_mutex); return rstc; } @@ -212,8 +253,9 @@ 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); 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, -- cgit v1.2.3 From 0b52297f2288ca239e598afe6c92db83d8d2bfcd Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 23 Feb 2016 18:46:26 +0100 Subject: reset: Add support for shared reset controls In some SoCs some hw-blocks share a reset control. Add support for this setup by adding new: reset_control_get_shared() devm_reset_control_get_shared() devm_reset_control_get_shared_by_index() methods to get a reset_control. Note that this patch omits adding of_ variants, if these are needed later they can be easily added. This patch also changes the behavior of the existing exclusive reset_control_get() variants, if these are now called more then once for the same reset_control they will return -EBUSY. To catch existing drivers triggering this error (there should not be any) a WARN_ON(1) is added in this path. When a reset_control is shared, the behavior of reset_control_assert / deassert is changed, for shared reset_controls these will work like the clock-enable/disable and regulator-on/off functions. They will keep 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. 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. Signed-off-by: Hans de Goede Signed-off-by: Philipp Zabel --- drivers/reset/core.c | 59 +++++++++++++++++++++++++------ include/linux/reset.h | 96 +++++++++++++++++++++++++++++++++++++++++++-------- 2 files changed, 129 insertions(+), 26 deletions(-) (limited to 'drivers/reset/core.c') diff --git a/drivers/reset/core.c b/drivers/reset/core.c index 957750600ff3..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 @@ -29,12 +30,16 @@ static LIST_HEAD(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; }; /** @@ -91,9 +96,14 @@ 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); @@ -104,26 +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); @@ -144,7 +176,7 @@ EXPORT_SYMBOL_GPL(reset_control_status); static struct reset_control *__reset_control_get( struct reset_controller_dev *rcdev, - unsigned int index) + unsigned int index, int shared) { struct reset_control *rstc; @@ -152,6 +184,9 @@ static struct reset_control *__reset_control_get( 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; } @@ -167,6 +202,7 @@ static struct reset_control *__reset_control_get( list_add(&rstc->list, &rcdev->reset_control_head); rstc->id = index; rstc->refcnt = 1; + rstc->shared = shared; return rstc; } @@ -185,7 +221,7 @@ static void __reset_control_put(struct reset_control *rstc) } struct reset_control *__of_reset_control_get(struct device_node *node, - const char *id, int index) + const char *id, int index, int shared) { struct reset_control *rstc; struct reset_controller_dev *r, *rcdev; @@ -235,7 +271,7 @@ struct reset_control *__of_reset_control_get(struct device_node *node, } /* reset_list_mutex also protects the rcdev's reset_control list */ - rstc = __reset_control_get(rcdev, rstc_id); + rstc = __reset_control_get(rcdev, rstc_id, shared); mutex_unlock(&reset_list_mutex); @@ -265,7 +301,7 @@ static void devm_reset_control_release(struct device *dev, void *res) } struct reset_control *__devm_reset_control_get(struct device *dev, - const char *id, int index) + const char *id, int index, int shared) { struct reset_control **ptr, *rstc; @@ -274,7 +310,8 @@ struct reset_control *__devm_reset_control_get(struct device *dev, if (!ptr) return ERR_PTR(-ENOMEM); - rstc = __of_reset_control_get(dev ? dev->of_node : NULL, id, index); + rstc = __of_reset_control_get(dev ? dev->of_node : NULL, + id, index, shared); if (!IS_ERR(rstc)) { *ptr = rstc; devres_add(dev, ptr); diff --git a/include/linux/reset.h b/include/linux/reset.h index 1bb69a29d6db..a552134a209e 100644 --- a/include/linux/reset.h +++ b/include/linux/reset.h @@ -13,10 +13,10 @@ int reset_control_deassert(struct reset_control *rstc); int reset_control_status(struct reset_control *rstc); struct reset_control *__of_reset_control_get(struct device_node *node, - const char *id, int index); + 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, int index); + const char *id, int index, int shared); int __must_check device_reset(struct device *dev); @@ -63,14 +63,14 @@ static inline int device_reset_optional(struct device *dev) static inline struct reset_control *__of_reset_control_get( struct device_node *node, - const char *id, int index) + const char *id, int index, int shared) { return ERR_PTR(-EINVAL); } static inline struct reset_control *__devm_reset_control_get( struct device *dev, - const char *id, int index) + const char *id, int index, int shared) { return ERR_PTR(-EINVAL); } @@ -78,11 +78,17 @@ static inline struct reset_control *__devm_reset_control_get( #endif /* CONFIG_RESET_CONTROLLER */ /** - * reset_control_get - Lookup and obtain a reference to a 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. */ @@ -92,17 +98,46 @@ static inline struct reset_control *__must_check reset_control_get( #ifndef CONFIG_RESET_CONTROLLER WARN_ON(1); #endif - return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0); + 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 __of_reset_control_get(dev ? dev->of_node : NULL, id, 0); + return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0); } /** - * of_reset_control_get - Lookup and obtain a reference to a reset controller. + * 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 * @@ -113,12 +148,12 @@ static inline struct reset_control *reset_control_get_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); + return __of_reset_control_get(node, id, 0, 0); } /** - * of_reset_control_get_by_index - Lookup and obtain a reference to a reset - * controller by index. + * 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 * @@ -129,7 +164,7 @@ static inline struct reset_control *of_reset_control_get( 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); + return __of_reset_control_get(node, NULL, index, 0); } /** @@ -147,13 +182,13 @@ static inline struct reset_control *__must_check devm_reset_control_get( #ifndef CONFIG_RESET_CONTROLLER WARN_ON(1); #endif - return __devm_reset_control_get(dev, id, 0); + 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 __devm_reset_control_get(dev, id, 0); + return __devm_reset_control_get(dev, id, 0, 0); } /** @@ -168,7 +203,38 @@ static inline struct reset_control *devm_reset_control_get_optional( static inline struct reset_control *devm_reset_control_get_by_index( struct device *dev, int index) { - return __devm_reset_control_get(dev, NULL, index); + return __devm_reset_control_get(dev, NULL, index, 0); +} + +/** + * 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 __devm_reset_control_get(dev, id, 0, 1); +} + +/** + * 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 -- cgit v1.2.3