Add a debugfs file to expose system clocks.
Signed-off-by: Jeremy Kerr <jeremy.k...@canonical.com>
---
Yong: as promised, here's the sample debug code for the common struck clk
---
arch/Kconfig | 4 +
arch/arm/common/clkdev.c | 2
include/linux/clk.h | 20 ++++++++
kernel/clk.c | 92 +++++++++++++++++++++++++++++++++++++++
4 files changed, 118 insertions(+)
diff --git a/arch/Kconfig b/arch/Kconfig
index 212bd3c..8c2e329 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -168,6 +168,10 @@ config HAVE_USER_RETURN_NOTIFIER
config USE_COMMON_STRUCT_CLK
bool
+config CLK_DEBUG
+ bool "Expose clock status information in debugfs"
+ depends on USE_COMMON_STRUCT_CLK && DEBUG_FS
+
config HAVE_PERF_EVENTS_NMI
bool
help
diff --git a/arch/arm/common/clkdev.c b/arch/arm/common/clkdev.c
index e2b2bb6..7524445 100644
--- a/arch/arm/common/clkdev.c
+++ b/arch/arm/common/clkdev.c
@@ -97,6 +97,7 @@ void clkdev_add(struct clk_lookup *cl)
{
mutex_lock(&clocks_mutex);
list_add_tail(&cl->node, &clocks);
+ clk_register(cl->clk);
mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clkdev_add);
@@ -106,6 +107,7 @@ void __init clkdev_add_table(struct clk_lookup *cl, size_t
num)
mutex_lock(&clocks_mutex);
while (num--) {
list_add_tail(&cl->node, &clocks);
+ clk_register(cl->clk);
cl++;
}
mutex_unlock(&clocks_mutex);
diff --git a/include/linux/clk.h b/include/linux/clk.h
index ae7e4ed..d6e64bf 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -20,6 +20,8 @@ struct device;
#ifdef CONFIG_USE_COMMON_STRUCT_CLK
+#define CLK_NAME_LEN 32
+
#define CLK_ATOMIC 0x1
/* If we're using the common struct clk, we define the base clk object here */
@@ -64,14 +66,25 @@ struct clk {
struct mutex mutex;
spinlock_t spinlock;
} lock;
+#ifdef CONFIG_CLK_DEBUG
+ const char name[CLK_NAME_LEN];
+ struct list_head list;
+#endif /* CONFIG_CLK_DEBUG */
};
+#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 */
@@ -80,6 +93,7 @@ struct clk {
.enable_count = 0, \
.flags = CLK_ATOMIC, \
.lock.spinlock = __SPIN_LOCK_UNLOCKED(name.lock.spinlock), \
+ __INIT_CLK_DEBUG(name) \
}
/**
@@ -308,4 +322,10 @@ 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
+extern void clk_register(struct clk *clk);
+#else
+static inline void clk_register(struct clk *clk) { }
+#endif
+
#endif
diff --git a/kernel/clk.c b/kernel/clk.c
index 2779abb..1969b0c 100644
--- a/kernel/clk.c
+++ b/kernel/clk.c
@@ -9,7 +9,11 @@
*/
#include <linux/clk.h>
+#include <linux/debugfs.h>
+#include <linux/fs.h>
#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
int clk_enable(struct clk *clk)
{
@@ -112,3 +116,91 @@ struct clk_ops clk_fixed_ops = {
.get_rate = clk_fixed_get_rate,
};
EXPORT_SYMBOL_GPL(clk_fixed_ops);
+
+#ifdef CONFIG_CLK_DEBUG
+static LIST_HEAD(clocks);
+static DEFINE_MUTEX(clocks_lock);
+
+void clk_register(struct clk *clk)
+{
+ struct clk *c;
+
+ mutex_lock(&clocks_lock);
+
+ /* Look for duplicates. Since we're being called from clkdev_add,
+ * we may see multiple clk_lookups for one clock, so seeing the same
+ * clock is fine. However, warn if we see different clocks with the
+ * same name */
+ list_for_each_entry(c, &clocks, list) {
+ if (c == clk)
+ goto out_unlock;
+
+ if (!strcmp(clk->name, c->name))
+ pr_warn("clock %s: duplicate name\n", clk->name);
+ }
+
+ list_add(&clk->list, &clocks);
+out_unlock:
+ mutex_unlock(&clocks_lock);
+}
+
+static void *clk_debug_seq_start(struct seq_file *m, loff_t *pos)
+{
+ mutex_lock(&clocks_lock);
+ return seq_list_start(&clocks, *pos);
+}
+
+static void *clk_debug_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ return seq_list_next(v, &clocks, pos);
+}
+
+static void clk_debug_seq_stop(struct seq_file *m, void *v)
+{
+ mutex_unlock(&clocks_lock);
+}
+
+static int clk_debug_seq_show(struct seq_file *m, void *v)
+{
+ struct clk *parent, *clk = list_entry(v, struct clk, list);
+ const char *parent_name = "root";
+
+ parent = clk_get_parent(clk);
+ if (parent && !IS_ERR(parent))
+ parent_name = parent->name;
+
+ seq_printf(m, "%s [parent %s] usecount %d rate %lu\n",
+ clk->name, parent_name,
+ clk->enable_count, clk_get_rate(clk));
+ return 0;
+}
+
+static const struct seq_operations clk_debug_seq_ops = {
+ .start = clk_debug_seq_start,
+ .next = clk_debug_seq_next,
+ .stop = clk_debug_seq_stop,
+ .show = clk_debug_seq_show,
+};
+
+static int clk_debug_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &clk_debug_seq_ops);
+}
+
+static const struct file_operations clk_debug_file_ops = {
+ .open = clk_debug_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+int clk_debug_init(void)
+{
+ debugfs_create_file("clocks", 0444, NULL, NULL,
+ &clk_debug_file_ops);
+ return 0;
+}
+
+late_initcall(clk_debug_init);
+
+#endif /* CONFIG_CLK_DEBUG */
_______________________________________________
linaro-dev mailing list
linaro-dev@lists.linaro.org
http://lists.linaro.org/mailman/listinfo/linaro-dev
