From d5622a9c13752be46e6fcde9d31391ce0bb0598b Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 2 Mar 2015 15:45:41 +0000 Subject: clkdev: use clk_hw internally clk_add_alias() calls clk_get() followed by clk_put() but in between those two calls it saves away the struct clk pointer to a clk_lookup structure. This leaves the 'clk' member of the clk_lookup pointing at freed memory on configurations where CONFIG_COMMON_CLK=y. This is a problem because clk_get_sys() will eventually try to dereference the freed pointer by calling __clk_get_hw() on it. Fix this by saving away the struct clk_hw pointer instead of the struct clk pointer so that when we try to create a per-user struct clk in clk_get_sys() we don't dereference a junk pointer. Signed-off-by: Russell King --- include/linux/clkdev.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/clkdev.h b/include/linux/clkdev.h index 94bad77eeb4a..3003afad46c9 100644 --- a/include/linux/clkdev.h +++ b/include/linux/clkdev.h @@ -22,6 +22,7 @@ struct clk_lookup { const char *dev_id; const char *con_id; struct clk *clk; + struct clk_hw *clk_hw; }; #define CLKDEV_INIT(d, n, c) \ -- cgit v1.2.3 From d2d14a77886485310ec66e575f00ea5232ac7a14 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sat, 14 Mar 2015 15:12:35 +0000 Subject: clk: update clk API documentation to clarify clk_round_rate() The idea is that rate = clk_round_rate(clk, r) is equivalent to: clk_set_rate(clk, r); rate = clk_get_rate(clk); except that clk_round_rate() does not change the hardware in any way. Signed-off-by: Russell King --- include/linux/clk.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'include/linux') diff --git a/include/linux/clk.h b/include/linux/clk.h index 68c16a6bedb3..cafb22df8d00 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -306,6 +306,20 @@ void devm_clk_put(struct device *dev, struct clk *clk); * @clk: clock source * @rate: desired clock rate in Hz * + * This answers the question "if I were to pass @rate to clk_set_rate(), + * what clock rate would I end up with?" without changing the hardware + * in any way. In other words: + * + * rate = clk_round_rate(clk, r); + * + * and: + * + * clk_set_rate(clk, r); + * rate = clk_get_rate(clk); + * + * are equivalent except the former does not modify the clock hardware + * in any way. + * * Returns rounded clock rate in Hz, or negative errno. */ long clk_round_rate(struct clk *clk, unsigned long rate); -- cgit v1.2.3 From 2d34e507293102f29ee94d9a9c5b890696d42452 Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 9 Mar 2015 11:03:00 +0000 Subject: clkdev: get rid of redundant clk_add_alias() prototype in linux/clk.h clk_add_alias() is provided by clkdev, and is not part of the clk API. Howver, it is prototyped in two locations: linux/clkdev.h and linux/clk.h. This is a mess. Get rid of the redundant and unnecessary version in linux/clk.h. Acked-by: Tony Lindgren Tested-by: Robert Jarzmik Acked-by: Sekhar Nori Signed-off-by: Russell King --- include/linux/clk.h | 13 ------------- 1 file changed, 13 deletions(-) (limited to 'include/linux') diff --git a/include/linux/clk.h b/include/linux/clk.h index cafb22df8d00..0df4a51e1a78 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -485,19 +485,6 @@ static inline void clk_disable_unprepare(struct clk *clk) clk_unprepare(clk); } -/** - * clk_add_alias - add a new clock alias - * @alias: name for clock alias - * @alias_dev_name: device name - * @id: platform specific clock name - * @dev: device - * - * Allows using generic clock names for drivers by adding a new alias. - * Assumes clkdev, see clkdev.h for more info. - */ -int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, - struct device *dev); - struct device_node; struct of_phandle_args; -- cgit v1.2.3 From b3d8d7e89fab374d731dfb46fe048f09766ca9c8 Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 9 Mar 2015 10:43:04 +0000 Subject: clkdev: const-ify connection id to clk_add_alias() The connection id is only passed to clk_get() which is already const. Const-ify this argument too. Signed-off-by: Russell King --- include/linux/clkdev.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/clkdev.h b/include/linux/clkdev.h index 3003afad46c9..cd93b215e3af 100644 --- a/include/linux/clkdev.h +++ b/include/linux/clkdev.h @@ -39,7 +39,7 @@ void clkdev_add(struct clk_lookup *cl); void clkdev_drop(struct clk_lookup *cl); void clkdev_add_table(struct clk_lookup *, size_t); -int clk_add_alias(const char *, const char *, char *, struct device *); +int clk_add_alias(const char *, const char *, const char *, struct device *); int clk_register_clkdev(struct clk *, const char *, const char *, ...); int clk_register_clkdevs(struct clk *, struct clk_lookup *, size_t); -- cgit v1.2.3 From 2568999835d7797afce3dcc3a3f368051ffcaf1f Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 2 Mar 2015 15:40:29 +0000 Subject: clkdev: add clkdev_create() helper Add a helper to allocate and add a clk_lookup structure. This can not only be used in several places in clkdev.c to simplify the code, but more importantly, can be used by callers of the clkdev code to simplify their clkdev creation and registration. Signed-off-by: Russell King --- include/linux/clkdev.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/clkdev.h b/include/linux/clkdev.h index cd93b215e3af..a240b18e86fa 100644 --- a/include/linux/clkdev.h +++ b/include/linux/clkdev.h @@ -38,6 +38,9 @@ struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id, void clkdev_add(struct clk_lookup *cl); void clkdev_drop(struct clk_lookup *cl); +struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id, + const char *dev_fmt, ...); + void clkdev_add_table(struct clk_lookup *, size_t); int clk_add_alias(const char *, const char *, const char *, struct device *); -- cgit v1.2.3