[PATCH] Common clock: To list active consumers of clocks

From: Vishal Badole
Date: Tue May 31 2022 - 11:53:34 EST

This feature lists the name of clocks and their consumer devices.
Using this feature user can easily check which device is using a
perticular clock.

for example:
debian@beaglebone:~$ cat /sys/kernel/debug/clk/clk_devices_name
clock_name devices_name
-------------------------------------------------------------------------
l4-wkup-clkctrl:0008:0 44e07000.target-module
l4ls-clkctrl:0074:0 4804c000.target-module
l4ls-clkctrl:0058:0 48311fe0.target-module
l4-rtc-clkctrl:0000:0 44e3e074.target-module
clk_32768_ck 44e3e000.rtc
l4ls-clkctrl:00d8:0 480c8000.target-module
cpsw-125mhz-clkctrl:0014:0 4a101200.target-module

Signed-off-by: Vishal Badole <badolevishal1116@xxxxxxxxx>
Signed-off-by: Chinmoy Ghosh <chinmoyghosh2001@xxxxxxxxx>
Signed-off-by: Mintu Patel <mintupatel89@xxxxxxxxx>
Signed-off-by: Vimal Kumar <vimal.kumar32@xxxxxxxxx>
---
drivers/clk/Kconfig | 8 ++++
drivers/clk/clk.c | 120 +++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 127 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index c44247d..549cdda 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -23,6 +23,14 @@ config COMMON_CLK
menu "Common Clock Framework"
depends on COMMON_CLK

+config DEBUG_CLK_CONSUMER
+ bool "Debug feature to list clocks and their active consumers"
+ depends on DEBUG_FS && COMMON_CLK
+ help
+ Clock consumer debug feature supports for clock debugging. Chose y
+ to get debug entry in file system to list clocks and their active
+ consumer devices.
+
config COMMON_CLK_WM831X
tristate "Clock driver for WM831x/2x PMICs"
depends on MFD_WM831X
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 13332f8..dccbd35 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -105,6 +105,84 @@ struct clk {
struct hlist_node clks_node;
};

+#ifdef CONFIG_DEBUG_CLK_CONSUMER
+/*Linked List Node*/
+struct clk_dev_list {
+ struct list_head list;
+ const char *clk_name;
+ const char *dev_name;
+};
+
+/*Declare and init the head node of the linked list*/
+LIST_HEAD(head_node);
+
+static void clk_dev_entry(struct clk *clk_ptr)
+{
+ struct clk_dev_list *new_node_ptr = NULL;
+ struct clk_dev_list *temp_node_ptr = NULL;
+ int repeat_count = 0;
+ static bool is_first_node;
+ const char *clk_name_ptr = NULL;
+ const char *dev_name_ptr = NULL;
+
+ if (clk_ptr->dev) {
+ dev_name_ptr = dev_name(clk_ptr->dev);
+
+ clk_name_ptr = clk_ptr->core->name;
+
+ if (is_first_node) {
+ /* Iterate the list to check duplicate entry */
+ list_for_each_entry(temp_node_ptr, &head_node, list) {
+ if (temp_node_ptr->clk_name == clk_name_ptr &&
+ temp_node_ptr->dev_name == dev_name_ptr) {
+ repeat_count++;
+ break;
+ }
+ }
+ }
+
+ is_first_node = 1;
+
+ if (!repeat_count && clk_ptr->core->enable_count) {
+ /*Creating Node*/
+ new_node_ptr = kmalloc(sizeof(*new_node_ptr),
+ GFP_KERNEL);
+ if (!new_node_ptr)
+ return;
+
+ /*Assgin the data that is received*/
+ new_node_ptr->clk_name = clk_name_ptr;
+ new_node_ptr->dev_name = dev_name_ptr;
+
+ /*Init the list within the struct*/
+ INIT_LIST_HEAD(&new_node_ptr->list);
+
+ /*Add Node to Linked List*/
+ list_add_tail(&new_node_ptr->list, &head_node);
+ }
+ }
+}
+
+/* Function to remove the clk and device entry */
+static void clk_dev_dentry(struct clk *clk)
+{
+ struct clk_dev_list *temp_node_ptr = NULL;
+ struct clk_dev_list *cur_node_ptr = NULL;
+
+ if (clk->dev) {
+ /* Go through the list and free the memory */
+ list_for_each_entry_safe(cur_node_ptr, temp_node_ptr,
+ &head_node, list) {
+ if (cur_node_ptr->clk_name == clk->core->name &&
+ cur_node_ptr->dev_name == dev_name(clk->dev)) {
+ list_del(&cur_node_ptr->list);
+ kfree(cur_node_ptr);
+ }
+ }
+ }
+}
+#endif
+
/*** runtime pm ***/
static int clk_pm_runtime_get(struct clk_core *core)
{
@@ -1020,6 +1098,9 @@ void clk_disable(struct clk *clk)
return;

clk_core_disable_lock(clk->core);
+#ifdef CONFIG_DEBUG_CLK_CONSUMER
+ clk_dev_dentry(clk);
+#endif
}
EXPORT_SYMBOL_GPL(clk_disable);

@@ -1181,10 +1262,21 @@ EXPORT_SYMBOL_GPL(clk_restore_context);
*/
int clk_enable(struct clk *clk)
{
+#ifdef CONFIG_DEBUG_CLK_CONSUMER
+ int ret = 0;
+#endif
if (!clk)
return 0;

+#ifndef CONFIG_DEBUG_CLK_CONSUMER
return clk_core_enable_lock(clk->core);
+#else
+ ret = clk_core_enable_lock(clk->core);
+ if (!ret)
+ clk_dev_entry(clk);
+
+ return ret;
+#endif
}
EXPORT_SYMBOL_GPL(clk_enable);

@@ -2986,6 +3078,29 @@ static void clk_dump_one(struct seq_file *s, struct clk_core *c, int level)
clk_core_get_scaled_duty_cycle(c, 100000));
}

+#ifdef CONFIG_DEBUG_CLK_CONSUMER
+static int clk_devices_show(struct seq_file *s, void *data)
+{
+ struct clk_dev_list *clk_dev_node;
+
+ seq_puts(s, " clock_name devices_name\n");
+ seq_puts(s, "-------------------------------------------------------------------------\n");
+
+ clk_prepare_lock();
+
+ /*Traversing Linked List and Print its Members*/
+ list_for_each_entry(clk_dev_node, &head_node, list) {
+ seq_printf(s, "%35s %35s\n", clk_dev_node->clk_name,
+ clk_dev_node->dev_name);
+ }
+
+ clk_prepare_unlock();
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(clk_devices);
+#endif
+
static void clk_dump_subtree(struct seq_file *s, struct clk_core *c, int level)
{
struct clk_core *child;
@@ -3256,7 +3371,10 @@ static int __init clk_debug_init(void)
&clk_summary_fops);
debugfs_create_file("clk_orphan_dump", 0444, rootdir, &orphan_list,
&clk_dump_fops);
-
+#ifdef CONFIG_DEBUG_CLK_CONSUMER
+ debugfs_create_file("clk_devices_name", 0444, rootdir, NULL,
+ &clk_devices_fops);
+#endif
mutex_lock(&clk_debug_lock);
hlist_for_each_entry(core, &clk_debug_list, debug_node)
clk_debug_create_one(core, rootdir);
--
2.7.4