Re: [PATCH 5.4] Common clock: ​​To list active consumers of clocks

Stephen Boyd
2022-06-10T19:40:22Z

Why "5.4" in the subject?

Quoting Vishal Badole (2022-05-31 11:28:35)
> This feature lists the name of clocks and their consumer devices. This
> debug feature can be used to check the active clocks and the devices who
> have enabled them.
>
> 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@gmail.com>
> Signed-off-by: Chinmoy Ghosh <chinmoyghosh2001@gmail.com>
> Signed-off-by: Mintu Patel <mintupatel89@gmail.com>
> Signed-off-by: Vimal Kumar <vimal.kumar32@gmail.com>

Where are the Co-developed-by tags? Also, your SoB should be last.

> ---
>  drivers/clk/Kconfig |   8 ++++
>  drivers/clk/clk.c   | 120 +++++++++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 127 insertions(+), 1 deletion(-)

The patch is malformed. Not sure what's happening with your MUA.

>
> 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"

Don't think we need a new config for this. Just add it to the existing
CONFIG_DEBUGFS area.

> + 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*/

Typo in Assign.

> + 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

Not sure what this is doing.

>  }
>  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) {

It's hard to read but we already have a list of all clk consumers for a
clk_hw pointer, see clk_core_link_consumer(). And we stash the device
consuming it with clk_hw_create_clk(). That should be sufficient.

> + 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,

Call it 'clk_consumers' please.

> +    &clk_devices_fops);