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author | Sylwester Nawrocki <s.nawrocki@samsung.com> | 2013-08-23 17:03:43 +0200 |
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committer | Sylwester Nawrocki <s.nawrocki@samsung.com> | 2013-12-04 17:19:30 +0100 |
commit | d6782c263661abd6c7e8a375141d69fdc457f9e1 (patch) | |
tree | 4e43750d3ddbcbe1de3696e1bcbe50e3e982acc2 /drivers | |
parent | 4eadfc38c4d6e30775d3764f9a1a3098789d2acc (diff) | |
download | linux-stable-d6782c263661abd6c7e8a375141d69fdc457f9e1.tar.gz linux-stable-d6782c263661abd6c7e8a375141d69fdc457f9e1.tar.bz2 linux-stable-d6782c263661abd6c7e8a375141d69fdc457f9e1.zip |
clk: Provide not locked variant of of_clk_get_from_provider()
Add helper functions for the of_clk_providers list locking and
an unlocked variant of of_clk_get_from_provider().
These functions are intended to be used in the clkdev to avoid
race condition in the device tree based clock look up in clk_get().
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/clk/clk.c | 38 | ||||
-rw-r--r-- | drivers/clk/clk.h | 16 |
2 files changed, 46 insertions, 8 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 77fcd069c64a..c687dc8d0b64 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -21,6 +21,8 @@ #include <linux/init.h> #include <linux/sched.h> +#include "clk.h" + static DEFINE_SPINLOCK(enable_lock); static DEFINE_MUTEX(prepare_lock); @@ -2111,7 +2113,18 @@ static const struct of_device_id __clk_of_table_sentinel __used __section(__clk_of_table_end); static LIST_HEAD(of_clk_providers); -static DEFINE_MUTEX(of_clk_lock); +static DEFINE_MUTEX(of_clk_mutex); + +/* of_clk_provider list locking helpers */ +void of_clk_lock(void) +{ + mutex_lock(&of_clk_mutex); +} + +void of_clk_unlock(void) +{ + mutex_unlock(&of_clk_mutex); +} struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec, void *data) @@ -2155,9 +2168,9 @@ int of_clk_add_provider(struct device_node *np, cp->data = data; cp->get = clk_src_get; - mutex_lock(&of_clk_lock); + mutex_lock(&of_clk_mutex); list_add(&cp->link, &of_clk_providers); - mutex_unlock(&of_clk_lock); + mutex_unlock(&of_clk_mutex); pr_debug("Added clock from %s\n", np->full_name); return 0; @@ -2172,7 +2185,7 @@ void of_clk_del_provider(struct device_node *np) { struct of_clk_provider *cp; - mutex_lock(&of_clk_lock); + mutex_lock(&of_clk_mutex); list_for_each_entry(cp, &of_clk_providers, link) { if (cp->node == np) { list_del(&cp->link); @@ -2181,24 +2194,33 @@ void of_clk_del_provider(struct device_node *np) break; } } - mutex_unlock(&of_clk_lock); + mutex_unlock(&of_clk_mutex); } EXPORT_SYMBOL_GPL(of_clk_del_provider); -struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec) +struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec) { struct of_clk_provider *provider; struct clk *clk = ERR_PTR(-ENOENT); /* Check if we have such a provider in our array */ - mutex_lock(&of_clk_lock); list_for_each_entry(provider, &of_clk_providers, link) { if (provider->node == clkspec->np) clk = provider->get(clkspec, provider->data); if (!IS_ERR(clk)) break; } - mutex_unlock(&of_clk_lock); + + return clk; +} + +struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec) +{ + struct clk *clk; + + mutex_lock(&of_clk_mutex); + clk = __of_clk_get_from_provider(clkspec); + mutex_unlock(&of_clk_mutex); return clk; } diff --git a/drivers/clk/clk.h b/drivers/clk/clk.h new file mode 100644 index 000000000000..795cc9f0dac0 --- /dev/null +++ b/drivers/clk/clk.h @@ -0,0 +1,16 @@ +/* + * linux/drivers/clk/clk.h + * + * Copyright (C) 2013 Samsung Electronics Co., Ltd. + * Sylwester Nawrocki <s.nawrocki@samsung.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) +struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec); +void of_clk_lock(void); +void of_clk_unlock(void); +#endif |