Date: Tue, 16 Nov 2010 15:00:28 +0800

Subject: [PATCH] export clock debug information to user space

create a tree-like directory structure in debugfs so user space tools like powerdebug can generate readable clock information.

more functions tend to be add in, like individual clock enable/disable by writing to this debugfs.

Signed-off-by: Yong Shen <yong.shen@linaro.org>

---

arch/arm/common/Kconfig | 7 +++

arch/arm/common/clkdev.c | 28 +++++++++++++

arch/arm/plat-mxc/clock-common.c | 5 ++-

include/linux/clk.h | 19 ++++++++-

kernel/clk.c | 83 ++++++++++++++++++++++++++++++++++++++

5 files changed, 139 insertions(+), 3 deletions(-)

diff --git a/arch/arm/common/Kconfig b/arch/arm/common/Kconfig

index 0a34c81..0300c95 100644

--- a/arch/arm/common/Kconfig

+++ b/arch/arm/common/Kconfig

@@ -41,3 +41,10 @@ config SHARP_SCOOP

config COMMON_CLKDEV

bool

select HAVE_CLK

+config CLK_DEBUG

+ bool "clock debug information export to user space"

+ depends on COMMON_CLKDEV && PM_DEBUG && DEBUG_FS

+ default n

+ help

+ export clk debug information to user space

diff --git a/arch/arm/common/clkdev.c b/arch/arm/common/clkdev.c

index 9e4c4d9..5f4a309 100644

--- a/arch/arm/common/clkdev.c

+++ b/arch/arm/common/clkdev.c

@@ -19,6 +19,9 @@

#include <linux/mutex.h>

#include <linux/clk.h>

#include <linux/slab.h>

+#ifdef CONFIG_CLK_DEBUG

+#include <linux/debugfs.h>

+#endif

#include <asm/clkdev.h>

@@ -186,3 +189,28 @@ void clkdev_drop(struct clk_lookup *cl)

kfree(cl);

}

EXPORT_SYMBOL(clkdev_drop);

+#ifdef CONFIG_CLK_DEBUG

+static int __init clk_debugfs_init(void)

+ struct clk_lookup *cl;

+ struct dentry *d;

+ int err;

+ d = debugfs_create_dir("clocks", NULL);

+ if (!d)

+ return -ENOMEM;

+ list_for_each_entry(cl, &clocks, node) {

+ err = clk_debugfs_register(cl->clk, d);

+ if (err)

+ goto err_out;

+ }

+ return 0;

+err_out:

+ debugfs_remove_recursive(d);

+ return err;

+late_initcall(clk_debugfs_init);

+#endif

diff --git a/arch/arm/plat-mxc/clock-common.c b/arch/arm/plat-mxc/clock-common.c

index 8911813..20d38a8 100644

--- a/arch/arm/plat-mxc/clock-common.c

+++ b/arch/arm/plat-mxc/clock-common.c

@@ -97,7 +97,10 @@ unsigned long clk_mxc_get_rate(struct clk *_clk)

if (clk->get_rate)

return clk->get_rate(clk);

- return clk_get_rate(clk->parent);

+ if (clk->parent)

+ return clk_get_rate(clk->parent);

+ return 0;

}

/* Round the requested clock rate to the nearest supported

diff --git a/include/linux/clk.h b/include/linux/clk.h

index 56416b7..751c086 100644

--- a/include/linux/clk.h

+++ b/include/linux/clk.h

@@ -44,16 +44,28 @@ struct device;

* registered with the arch-specific clock management code; the clock driver

* code does not need to handle these.

+#define CLK_NAME_LEN 32

struct clk {

const struct clk_ops *ops;

unsigned int enable_count;

struct mutex mutex;

+#ifdef CONFIG_CLK_DEBUG

+ char name[CLK_NAME_LEN];

+ struct dentry *dentry;

+#endif

};

-#define INIT_CLK(name, o) { \

+#ifdef CONFIG_CLK_DEBUG

+#define __INIT_CLK_DEBUG(n) .name = #n,

+#else

+#define __INIT_CLK_DEBUG(n)

+#endif

+#define INIT_CLK(clk_name, o) { \

.ops = &o, \

.enable_count = 0, \

- .mutex = __MUTEX_INITIALIZER(name.mutex), \

+ .mutex = __MUTEX_INITIALIZER(clk_name.mutex), \

+ __INIT_CLK_DEBUG(clk_name) \

}

struct clk_ops {

@@ -245,4 +257,7 @@ struct clk *clk_get_sys(const char *dev_id, const char *con_id);

int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,

struct device *dev);

+#ifdef CONFIG_CLK_DEBUG

+int clk_debugfs_register(struct clk *clk, struct dentry *root);

+#endif

#endif

diff --git a/kernel/clk.c b/kernel/clk.c

index 32f25ef..97e5e66 100644

--- a/kernel/clk.c

+++ b/kernel/clk.c

@@ -12,6 +12,10 @@

#include <linux/mutex.h>

#include <linux/module.h>

+#ifdef CONFIG_CLK_DEBUG

+#include <linux/debugfs.h>

+#endif

int clk_enable(struct clk *clk)

{

int ret = 0;

@@ -113,3 +117,82 @@ struct clk_ops clk_fixed_ops = {

.get_rate = clk_fixed_get_rate,

};

EXPORT_SYMBOL_GPL(clk_fixed_ops);

+#ifdef CONFIG_CLK_DEBUG

+/*

+ * debugfs support to trace clock tree hierarchy and attributes

+ */

+static int clk_debug_rate_get(void *data, u64 *val)

+ struct clk *clk = data;

+ *val = (u64)clk_get_rate(clk);

+ return 0;

+DEFINE_SIMPLE_ATTRIBUTE(clk_debug_rate_fops, clk_debug_rate_get, NULL,

+ "%llu\n");

+static int clk_debugfs_register_one(struct clk *clk, struct dentry *root)

+ int err;

+ struct dentry *d, *child, *child_tmp;

+ struct clk *pa = clk_get_parent(clk);

+ if (pa && !IS_ERR(pa))

+ d = debugfs_create_dir(clk->name, pa->dentry);

+ else

+ d = debugfs_create_dir(clk->name, root);

+ if (!d)

+ return -ENOMEM;

+ clk->dentry = d;

+ d = debugfs_create_u32("enable_count", S_IRUGO, clk->dentry,

+ (u32 *)&clk->enable_count);

+ if (!d) {

+ err = -ENOMEM;

+ goto err_out;

+ }

+ d = debugfs_create_file("rate", S_IRUGO, clk->dentry, (void *)clk,

+ &clk_debug_rate_fops);

+ if (!d) {

+ err = -ENOMEM;

+ goto err_out;

+ }

+ return 0;

+err_out:

+ d = clk->dentry;

+ list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)

+ debugfs_remove(child);

+ debugfs_remove(clk->dentry);

+ return err;

+int clk_debugfs_register(struct clk *clk, struct dentry *root)

+ int err;

+ struct clk *pa;

+ pa = clk_get_parent(clk);

+ if (pa && !IS_ERR(pa) && !pa->dentry) {

+ err = clk_debugfs_register(pa, root);

+ if (err)

+ return err;

+ }

+ if (!clk->dentry) {

+ err = clk_debugfs_register_one(clk, root);

+ if (err)

+ return err;

+ }

+ return 0;

+EXPORT_SYMBOL_GPL(clk_debugfs_register);

+#endif /* defined CONFIG_CLK_DEBUG */

1.7.0.4

Cheers

Yong

On Tue, Nov 16, 2010 at 5:16 PM, Jeremy Kerr <jeremy.kerr@canonical.com> wrote:

Hi Yong,

Looks good, just a couple of things:

> diff --git a/arch/arm/common/clkdev.c b/arch/arm/common/clkdev.c
> index 9e4c4d9..cf81e70 100644
> --- a/arch/arm/common/clkdev.c
> +++ b/arch/arm/common/clkdev.c

Why not do this in the core clock code (kernel/clk.c) instead? No need to make
it ARM-specific.

> diff --git a/arch/arm/plat-mxc/clock-common.c
> b/arch/arm/plat-mxc/clock-common.c
> index 8911813..20d38a8 100644
> --- a/arch/arm/plat-mxc/clock-common.c
> +++ b/arch/arm/plat-mxc/clock-common.c
> @@ -97,7 +97,10 @@ unsigned long clk_mxc_get_rate(struct clk *_clk)
> if (clk->get_rate)
> return clk->get_rate(clk);
>
> - return clk_get_rate(clk->parent);
> + if (clk->parent)
> + return clk_get_rate(clk->parent);
> +
> + return 0;
> }
>
> /* Round the requested clock rate to the nearest supported
> diff --git a/include/linux/clk.h b/include/linux/clk.h
> index 56416b7..1102c2c 100644
> --- a/include/linux/clk.h
> +++ b/include/linux/clk.h
> @@ -44,17 +44,31 @@ struct device;
> * registered with the arch-specific clock management code; the clock
> driver
> * code does not need to handle these.
> */
> +#define CLK_NAME_LEN 16

We might need more than 16 bytes here; 32 should be fine.

> struct clk {
> const struct clk_ops *ops;
> unsigned int enable_count;
> struct mutex mutex;
> +#ifdef CONFIG_CLK_DEBUG
> + char name[CLK_NAME_LEN];
> + struct dentry *dentry;
> +#endif
> };
>
> -#define INIT_CLK(name, o) { \
> +#ifndef CONFIG_CLK_DEBUG
> +#define INIT_CLK(clk_name, o) { \
> .ops = &o, \
> .enable_count = 0, \
> - .mutex = __MUTEX_INITIALIZER(name.mutex), \
> + .mutex = __MUTEX_INITIALIZER(clk_name.mutex), \
> }
> +#else
> +#define INIT_CLK(clk_name, o) { \
> + .ops = &o, \
> + .enable_count = 0, \
> + .mutex = __MUTEX_INITIALIZER(clk_name.mutex), \
> + .name = #clk_name, \
> +}
> +#endif

How about this instead:

+#ifdef CONFIG_CLK_DEBUG
+#define __INIT_CLK_DEBUG(n) .name = #n,
+#else
+#define __INIT_CLK_DEBUG(n)
+#endif
+

/* static initialiser for non-atomic clocks */

#define INIT_CLK(name, o) { \

.ops = &o, \
.enable_count = 0, \

.flags = 0, \
.lock.mutex = __MUTEX_INITIALIZER(name.lock.mutex), \
+ __INIT_CLK_DEBUG(name) \
}

/* static initialiser for atomic clocks */

- otherwise, you're going to need to add another definition of INIT_CLK_ATOMIC
too, giving four in total.

Cheers,

Jeremy