[PATCH] mmc: append a file to change host clock at run time

[PATCH] mmc: append a file to change host clock at run time

[Andy Shevchenko]

For debugging power managment features there is quite convenient to have a
possibility to change MMC host controller clock at run time. This patch adds
'clock' file under MMC host root of debugfs.

Usage as follows:

	# cat /sys/kernel/debug/mmc0/clock
	24000000

	# echo "1000000000" > /sys/kernel/debug/mmc0/clock
	# cat /sys/kernel/debug/mmc0/clock
	52000000

	# echo "48000000" > /sys/kernel/debug/mmc0/clock
	# cat /sys/kernel/debug/mmc0/clock
	48000000

The second piece of example shows limits which are applied accordingly to used
host driver.

Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
---
 drivers/mmc/core/debugfs.c |   33 +++++++++++++++++++++++++++++++--
 1 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 96d10f4..4ff109f 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -133,6 +133,31 @@ static const struct file_operations mmc_ios_fops = {
 	.release	= single_release,
 };
 
+static int mmc_clock_opt_get(void *data, u64 *val)
+{
+	struct mmc_host *host = data;
+
+	*val = host->ios.clock;
+
+	return 0;
+}
+
+static int mmc_clock_opt_set(void *data, u64 val)
+{
+	struct mmc_host *host = data;
+
+	/* We need this check due to input value is u64 */
+	if (val > host->f_max)
+		return -EINVAL;
+
+	mmc_set_clock(host, (unsigned int) val);
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(mmc_clock_fops, mmc_clock_opt_get, mmc_clock_opt_set,
+	"%llu\n");
+
 void mmc_add_host_debugfs(struct mmc_host *host)
 {
 	struct dentry *root;
@@ -149,11 +174,15 @@ void mmc_add_host_debugfs(struct mmc_host *host)
 	host->debugfs_root = root;
 
 	if (!debugfs_create_file("ios", S_IRUSR, root, host, &mmc_ios_fops))
-		goto err_ios;
+		goto err_node;
+
+	if (!debugfs_create_file("clock", S_IRUSR | S_IWUSR, root, host,
+			&mmc_clock_fops))
+		goto err_node;
 
 	return;
 
-err_ios:
+err_node:
 	debugfs_remove_recursive(root);
 	host->debugfs_root = NULL;
 err_root:
-- 
1.6.3.3

Re: [PATCH] mmc: append a file to change host clock at run time

[Andy Shevchenko]

On Tue, Oct 12, 2010 at 6:17 PM, Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> For debugging power managment features there is quite convenient to have a
> possibility to change MMC host controller clock at run time. This patch adds
> 'clock' file under MMC host root of debugfs.
>
> Usage as follows:
>
>        # cat /sys/kernel/debug/mmc0/clock
>        24000000
Actually this value should be 52000000 here.

>
>        # echo "1000000000" > /sys/kernel/debug/mmc0/clock
>        # cat /sys/kernel/debug/mmc0/clock
>        52000000
>
>        # echo "48000000" > /sys/kernel/debug/mmc0/clock
>        # cat /sys/kernel/debug/mmc0/clock
>        48000000
>
> The second piece of example shows limits which are applied accordingly to used
> host driver.


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] mmc: append a file to change host clock at run time

[Adrian Hunter]

On 12/10/10 18:17, Andy Shevchenko wrote:
> For debugging power managment features there is quite convenient to have a
> possibility to change MMC host controller clock at run time. This patch adds
> 'clock' file under MMC host root of debugfs.
>
> Usage as follows:
>
> 	# cat /sys/kernel/debug/mmc0/clock
> 	24000000
>
> 	# echo "1000000000">  /sys/kernel/debug/mmc0/clock
> 	# cat /sys/kernel/debug/mmc0/clock
> 	52000000
>
> 	# echo "48000000">  /sys/kernel/debug/mmc0/clock
> 	# cat /sys/kernel/debug/mmc0/clock
> 	48000000
>
> The second piece of example shows limits which are applied accordingly to used
> host driver.
>
> Signed-off-by: Andy Shevchenko<ext-andriy.shevchenko@nokia.com>
> ---
>   drivers/mmc/core/debugfs.c |   33 +++++++++++++++++++++++++++++++--
>   1 files changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
> index 96d10f4..4ff109f 100644
> --- a/drivers/mmc/core/debugfs.c
> +++ b/drivers/mmc/core/debugfs.c
> @@ -133,6 +133,31 @@ static const struct file_operations mmc_ios_fops = {
>   	.release	= single_release,
>   };
>
> +static int mmc_clock_opt_get(void *data, u64 *val)
> +{
> +	struct mmc_host *host = data;
> +
> +	*val = host->ios.clock;
> +
> +	return 0;
> +}
> +
> +static int mmc_clock_opt_set(void *data, u64 val)
> +{
> +	struct mmc_host *host = data;
> +
> +	/* We need this check due to input value is u64 */
> +	if (val>  host->f_max)
> +		return -EINVAL;
> +
> +	mmc_set_clock(host, (unsigned int) val);

Probably need to claim the host here otherwise you might
be changing the clock while a request is in progress

> +
> +	return 0;
> +}
> +
> +DEFINE_SIMPLE_ATTRIBUTE(mmc_clock_fops, mmc_clock_opt_get, mmc_clock_opt_set,
> +	"%llu\n");
> +
>   void mmc_add_host_debugfs(struct mmc_host *host)
>   {
>   	struct dentry *root;
> @@ -149,11 +174,15 @@ void mmc_add_host_debugfs(struct mmc_host *host)
>   	host->debugfs_root = root;
>
>   	if (!debugfs_create_file("ios", S_IRUSR, root, host,&mmc_ios_fops))
> -		goto err_ios;
> +		goto err_node;
> +
> +	if (!debugfs_create_file("clock", S_IRUSR | S_IWUSR, root, host,
> +			&mmc_clock_fops))
> +		goto err_node;
>
>   	return;
>
> -err_ios:
> +err_node:
>   	debugfs_remove_recursive(root);
>   	host->debugfs_root = NULL;
>   err_root:

Re: [PATCH] mmc: append a file to change host clock at run time

[Adrian Hunter]

On 12/10/10 18:17, Andy Shevchenko wrote:
> For debugging power managment features there is quite convenient to have a
> possibility to change MMC host controller clock at run time. This patch adds
> 'clock' file under MMC host root of debugfs.
>
> Usage as follows:
>
> 	# cat /sys/kernel/debug/mmc0/clock
> 	24000000
>
> 	# echo "1000000000">  /sys/kernel/debug/mmc0/clock
> 	# cat /sys/kernel/debug/mmc0/clock
> 	52000000
>
> 	# echo "48000000">  /sys/kernel/debug/mmc0/clock
> 	# cat /sys/kernel/debug/mmc0/clock
> 	48000000
>
> The second piece of example shows limits which are applied accordingly to used
> host driver.
>
> Signed-off-by: Andy Shevchenko<ext-andriy.shevchenko@nokia.com>
> ---
>   drivers/mmc/core/debugfs.c |   33 +++++++++++++++++++++++++++++++--
>   1 files changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
> index 96d10f4..4ff109f 100644
> --- a/drivers/mmc/core/debugfs.c
> +++ b/drivers/mmc/core/debugfs.c
> @@ -133,6 +133,31 @@ static const struct file_operations mmc_ios_fops = {
>   	.release	= single_release,
>   };
>
> +static int mmc_clock_opt_get(void *data, u64 *val)
> +{
> +	struct mmc_host *host = data;
> +
> +	*val = host->ios.clock;
> +
> +	return 0;
> +}
> +
> +static int mmc_clock_opt_set(void *data, u64 val)
> +{
> +	struct mmc_host *host = data;
> +
> +	/* We need this check due to input value is u64 */
> +	if (val>  host->f_max)
> +		return -EINVAL;
> +
> +	mmc_set_clock(host, (unsigned int) val);

Probably need to claim the host here otherwise you might
be changing the clock while a request is in progress

> +
> +	return 0;
> +}
> +
> +DEFINE_SIMPLE_ATTRIBUTE(mmc_clock_fops, mmc_clock_opt_get, mmc_clock_opt_set,
> +	"%llu\n");
> +
>   void mmc_add_host_debugfs(struct mmc_host *host)
>   {
>   	struct dentry *root;
> @@ -149,11 +174,15 @@ void mmc_add_host_debugfs(struct mmc_host *host)
>   	host->debugfs_root = root;
>
>   	if (!debugfs_create_file("ios", S_IRUSR, root, host,&mmc_ios_fops))
> -		goto err_ios;
> +		goto err_node;
> +
> +	if (!debugfs_create_file("clock", S_IRUSR | S_IWUSR, root, host,
> +			&mmc_clock_fops))
> +		goto err_node;
>
>   	return;
>
> -err_ios:
> +err_node:
>   	debugfs_remove_recursive(root);
>   	host->debugfs_root = NULL;
>   err_root:

Re: [PATCH] mmc: append a file to change host clock at run time

[Andy Shevchenko]

On Wed, Oct 13, 2010 at 11:07 AM, Adrian Hunter <adrian.hunter@nokia.com> wrote:
>> +static int mmc_clock_opt_set(void *data, u64 val)
>> +{
>> +       struct mmc_host *host = data;
>> +
>> +       /* We need this check due to input value is u64 */
>> +       if (val>  host->f_max)
>> +               return -EINVAL;
>> +
>> +       mmc_set_clock(host, (unsigned int) val);
>
> Probably need to claim the host here otherwise you might
> be changing the clock while a request is in progress
Yeah, good catch. Will fix. Thanks.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] mmc: append a file to change host clock at run time

[Andy Shevchenko]

On Wed, Oct 13, 2010 at 11:07 AM, Adrian Hunter <adrian.hunter@nokia.com> wrote:
>> +static int mmc_clock_opt_set(void *data, u64 val)
>> +{
>> +       struct mmc_host *host = data;
>> +
>> +       /* We need this check due to input value is u64 */
>> +       if (val>  host->f_max)
>> +               return -EINVAL;
>> +
>> +       mmc_set_clock(host, (unsigned int) val);
>
> Probably need to claim the host here otherwise you might
> be changing the clock while a request is in progress
Yeah, good catch. Will fix. Thanks.

-- 
With Best Regards,
Andy Shevchenko

[PATCHv2] mmc: append a file to change host clock at run time

[Andy Shevchenko]

For debugging power managment features there is quite convenient to have a
possibility to change MMC host controller clock at run time. This patch adds
'clock' file under MMC host root of debugfs.

Usage as follows:

	# cat /sys/kernel/debug/mmc0/clock
	52000000

	# echo "1000000000" > /sys/kernel/debug/mmc0/clock
	# cat /sys/kernel/debug/mmc0/clock
	52000000

	# echo "48000000" > /sys/kernel/debug/mmc0/clock
	# cat /sys/kernel/debug/mmc0/clock
	48000000

The second piece of example shows limits which are applied accordingly to used
host driver.

Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
---
 drivers/mmc/core/debugfs.c |   35 +++++++++++++++++++++++++++++++++--
 1 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 96d10f4..9b6ec07 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -133,6 +133,33 @@ static const struct file_operations mmc_ios_fops = {
 	.release	= single_release,
 };
 
+static int mmc_clock_opt_get(void *data, u64 *val)
+{
+	struct mmc_host *host = data;
+
+	*val = host->ios.clock;
+
+	return 0;
+}
+
+static int mmc_clock_opt_set(void *data, u64 val)
+{
+	struct mmc_host *host = data;
+
+	/* We need this check due to input value is u64 */
+	if (val > host->f_max)
+		return -EINVAL;
+
+	mmc_claim_host(host);
+	mmc_set_clock(host, (unsigned int) val);
+	mmc_release_host(host);
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(mmc_clock_fops, mmc_clock_opt_get, mmc_clock_opt_set,
+	"%llu\n");
+
 void mmc_add_host_debugfs(struct mmc_host *host)
 {
 	struct dentry *root;
@@ -149,11 +176,15 @@ void mmc_add_host_debugfs(struct mmc_host *host)
 	host->debugfs_root = root;
 
 	if (!debugfs_create_file("ios", S_IRUSR, root, host, &mmc_ios_fops))
-		goto err_ios;
+		goto err_node;
+
+	if (!debugfs_create_file("clock", S_IRUSR | S_IWUSR, root, host,
+			&mmc_clock_fops))
+		goto err_node;
 
 	return;
 
-err_ios:
+err_node:
 	debugfs_remove_recursive(root);
 	host->debugfs_root = NULL;
 err_root:
-- 
1.6.3.3

Re: [PATCHv2] mmc: append a file to change host clock at run time

[Chris Ball]

Hi Andy,

On Wed, Oct 13, 2010 at 11:22:22AM +0300, Andy Shevchenko wrote:
> For debugging power managment features there is quite convenient to have a
> possibility to change MMC host controller clock at run time. This patch adds
> 'clock' file under MMC host root of debugfs.
> 
> Usage as follows:
> 
> 	# cat /sys/kernel/debug/mmc0/clock
> 	52000000
> 
> 	# echo "1000000000" > /sys/kernel/debug/mmc0/clock
> 	# cat /sys/kernel/debug/mmc0/clock
> 	52000000
> 
> 	# echo "48000000" > /sys/kernel/debug/mmc0/clock
> 	# cat /sys/kernel/debug/mmc0/clock
> 	48000000
> 
> The second piece of example shows limits which are applied accordingly to used
> host driver.
> 
> Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
> ---
>  drivers/mmc/core/debugfs.c |   35 +++++++++++++++++++++++++++++++++--
>  1 files changed, 33 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
> index 96d10f4..9b6ec07 100644
> --- a/drivers/mmc/core/debugfs.c
> +++ b/drivers/mmc/core/debugfs.c
> @@ -133,6 +133,33 @@ static const struct file_operations mmc_ios_fops = {
>  	.release	= single_release,
>  };
>  
> +static int mmc_clock_opt_get(void *data, u64 *val)
> +{
> +	struct mmc_host *host = data;
> +
> +	*val = host->ios.clock;
> +
> +	return 0;
> +}
> +
> +static int mmc_clock_opt_set(void *data, u64 val)
> +{
> +	struct mmc_host *host = data;
> +
> +	/* We need this check due to input value is u64 */
> +	if (val > host->f_max)
> +		return -EINVAL;
> +
> +	mmc_claim_host(host);
> +	mmc_set_clock(host, (unsigned int) val);
> +	mmc_release_host(host);
> +
> +	return 0;
> +}
> +
> +DEFINE_SIMPLE_ATTRIBUTE(mmc_clock_fops, mmc_clock_opt_get, mmc_clock_opt_set,
> +	"%llu\n");
> +
>  void mmc_add_host_debugfs(struct mmc_host *host)
>  {
>  	struct dentry *root;
> @@ -149,11 +176,15 @@ void mmc_add_host_debugfs(struct mmc_host *host)
>  	host->debugfs_root = root;
>  
>  	if (!debugfs_create_file("ios", S_IRUSR, root, host, &mmc_ios_fops))
> -		goto err_ios;
> +		goto err_node;
> +
> +	if (!debugfs_create_file("clock", S_IRUSR | S_IWUSR, root, host,
> +			&mmc_clock_fops))
> +		goto err_node;
>  
>  	return;
>  
> -err_ios:
> +err_node:
>  	debugfs_remove_recursive(root);
>  	host->debugfs_root = NULL;
>  err_root:
> -- 

Thanks, looks good -- applied to mmc-next with minor changelog edits.

-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child