From ac2df527fb407b61f9c812a99035b62a75a77d6d Mon Sep 17 00:00:00 2001 From: Sylwester Nawrocki Date: Sat, 24 Aug 2013 20:10:41 +0200 Subject: clk: Add common __clk_get(), __clk_put() implementations This patch adds common __clk_get(), __clk_put() clkdev helpers that replace their platform specific counterparts when the common clock API is used. The owner module pointer field is added to struct clk so a reference to the clock supplier module can be taken by the clock consumers. The owner module is assigned while the clock is being registered, in functions _clk_register() and __clk_register(). Signed-off-by: Sylwester Nawrocki Signed-off-by: Kyungmin Park Acked-by: Russell King --- include/linux/clk-private.h | 3 +++ include/linux/clkdev.h | 5 +++++ 2 files changed, 8 insertions(+) (limited to 'include/linux') diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h index 8138c94409f3..8cb1865e7d9d 100644 --- a/include/linux/clk-private.h +++ b/include/linux/clk-private.h @@ -25,10 +25,13 @@ #ifdef CONFIG_COMMON_CLK +struct module; + struct clk { const char *name; const struct clk_ops *ops; struct clk_hw *hw; + struct module *owner; struct clk *parent; const char **parent_names; struct clk **parents; diff --git a/include/linux/clkdev.h b/include/linux/clkdev.h index a6a6f603103b..94bad77eeb4a 100644 --- a/include/linux/clkdev.h +++ b/include/linux/clkdev.h @@ -43,4 +43,9 @@ int clk_add_alias(const char *, const char *, char *, struct device *); int clk_register_clkdev(struct clk *, const char *, const char *, ...); int clk_register_clkdevs(struct clk *, struct clk_lookup *, size_t); +#ifdef CONFIG_COMMON_CLK +int __clk_get(struct clk *clk); +void __clk_put(struct clk *clk); +#endif + #endif -- cgit v1.2.3-71-gd317 From fcb0ee6a3d331fb23dbb546500021f6e4cac5689 Mon Sep 17 00:00:00 2001 From: Sylwester Nawrocki Date: Sat, 24 Aug 2013 15:00:10 +0200 Subject: clk: Implement clk_unregister clk_unregister() is currently not implemented and it is required when a clock provider module needs to be unloaded. Normally the clock supplier module is prevented to be unloaded by taking reference on the module in clk_get(). For cases when the clock supplier module deinitializes despite the consumers of its clocks holding a reference on the module, e.g. when the driver is unbound through "unbind" sysfs attribute, there are empty clock ops added. These ops are assigned temporarily to struct clk and used until all consumers release the clock, to avoid invoking callbacks from the module which just got removed. Signed-off-by: Jiada Wang Signed-off-by: Sylwester Nawrocki Signed-off-by: Kyungmin Park --- drivers/clk/clk.c | 121 ++++++++++++++++++++++++++++++++++++++++++-- include/linux/clk-private.h | 2 + 2 files changed, 120 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index baa2f66a7d19..da7b33e4c5a2 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -345,6 +345,21 @@ out: return ret; } + /** + * clk_debug_unregister - remove a clk node from the debugfs clk tree + * @clk: the clk being removed from the debugfs clk tree + * + * Dynamically removes a clk and all it's children clk nodes from the + * debugfs clk tree if clk->dentry points to debugfs created by + * clk_debug_register in __clk_init. + * + * Caller must hold prepare_lock. + */ +static void clk_debug_unregister(struct clk *clk) +{ + debugfs_remove_recursive(clk->dentry); +} + /** * clk_debug_reparent - reparent clk node in the debugfs clk tree * @clk: the clk being reparented @@ -435,6 +450,9 @@ static inline int clk_debug_register(struct clk *clk) { return 0; } static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent) { } +static inline void clk_debug_unregister(struct clk *clk) +{ +} #endif /* caller must hold prepare_lock */ @@ -1778,6 +1796,7 @@ int __clk_init(struct device *dev, struct clk *clk) clk_debug_register(clk); + kref_init(&clk->ref); out: clk_prepare_unlock(); @@ -1913,13 +1932,104 @@ fail_out: } EXPORT_SYMBOL_GPL(clk_register); +/* + * Free memory allocated for a clock. + * Caller must hold prepare_lock. + */ +static void __clk_release(struct kref *ref) +{ + struct clk *clk = container_of(ref, struct clk, ref); + int i = clk->num_parents; + + kfree(clk->parents); + while (--i >= 0) + kfree(clk->parent_names[i]); + + kfree(clk->parent_names); + kfree(clk->name); + kfree(clk); +} + +/* + * Empty clk_ops for unregistered clocks. These are used temporarily + * after clk_unregister() was called on a clock and until last clock + * consumer calls clk_put() and the struct clk object is freed. + */ +static int clk_nodrv_prepare_enable(struct clk_hw *hw) +{ + return -ENXIO; +} + +static void clk_nodrv_disable_unprepare(struct clk_hw *hw) +{ + WARN_ON_ONCE(1); +} + +static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + return -ENXIO; +} + +static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index) +{ + return -ENXIO; +} + +static const struct clk_ops clk_nodrv_ops = { + .enable = clk_nodrv_prepare_enable, + .disable = clk_nodrv_disable_unprepare, + .prepare = clk_nodrv_prepare_enable, + .unprepare = clk_nodrv_disable_unprepare, + .set_rate = clk_nodrv_set_rate, + .set_parent = clk_nodrv_set_parent, +}; + /** * clk_unregister - unregister a currently registered clock * @clk: clock to unregister - * - * Currently unimplemented. */ -void clk_unregister(struct clk *clk) {} +void clk_unregister(struct clk *clk) +{ + unsigned long flags; + + if (!clk || WARN_ON_ONCE(IS_ERR(clk))) + return; + + clk_prepare_lock(); + + if (clk->ops == &clk_nodrv_ops) { + pr_err("%s: unregistered clock: %s\n", __func__, clk->name); + goto out; + } + /* + * Assign empty clock ops for consumers that might still hold + * a reference to this clock. + */ + flags = clk_enable_lock(); + clk->ops = &clk_nodrv_ops; + clk_enable_unlock(flags); + + if (!hlist_empty(&clk->children)) { + struct clk *child; + + /* Reparent all children to the orphan list. */ + hlist_for_each_entry(child, &clk->children, child_node) + clk_set_parent(child, NULL); + } + + clk_debug_unregister(clk); + + hlist_del_init(&clk->child_node); + + if (clk->prepare_count) + pr_warn("%s: unregistering prepared clock: %s\n", + __func__, clk->name); + + kref_put(&clk->ref, __clk_release); +out: + clk_prepare_unlock(); +} EXPORT_SYMBOL_GPL(clk_unregister); static void devm_clk_release(struct device *dev, void *res) @@ -1987,6 +2097,7 @@ int __clk_get(struct clk *clk) if (clk && !try_module_get(clk->owner)) return 0; + kref_get(&clk->ref); return 1; } @@ -1995,6 +2106,10 @@ void __clk_put(struct clk *clk) if (WARN_ON_ONCE(IS_ERR(clk))) return; + clk_prepare_lock(); + kref_put(&clk->ref, __clk_release); + clk_prepare_unlock(); + if (clk) module_put(clk->owner); } diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h index 8cb1865e7d9d..72c65e05450b 100644 --- a/include/linux/clk-private.h +++ b/include/linux/clk-private.h @@ -12,6 +12,7 @@ #define __LINUX_CLK_PRIVATE_H #include +#include #include /* @@ -50,6 +51,7 @@ struct clk { #ifdef CONFIG_COMMON_CLK_DEBUG struct dentry *dentry; #endif + struct kref ref; }; /* -- cgit v1.2.3-71-gd317