[PATCH 0/2] watchdog: bcm281xx: Debugfs support

[PATCH 0/2] watchdog: bcm281xx: Debugfs support

[Markus Mayer]

This series adds debugfs support to the bcm281xx watchdog driver. Most
of the code submitted here was already included as part of v5 of the
original driver submission. See
http://www.spinics.net/lists/linux-watchdog/msg03328.html

However, the debugfs code has since been broken out of the original
driver submission and the following changes have been made over what
was submitted earlier:

- The global variable busy_count is now, instead, part of struct
  bcm_kona_wdt.
- As a result secure_register_read() now needs to take a struct
  bcm_kona_wdt * and a register offset as its arguments.
- debugfs setup and teardown is now performed by
  bcm_kona_wdt_debug_init() and bcm_kona_wdt_debug_exit() rather than
  by using #ifdefs in bcm_kona_wdt_probe() and
  bcm_kona_wdt_debug_exit().

This series is dependent on commit
bd90ccd42c5d6317979c62919ba1c79fd34fa785 in linux-watchdog-next.

Markus Mayer (2):
  watchdog: bcm281xx: Debugfs support
  watchdog: bcm281xx: Turn on debugfs support for watchdog driver

 arch/arm/configs/bcm_defconfig  |    1 +
 drivers/watchdog/Kconfig        |   10 ++++
 drivers/watchdog/bcm_kona_wdt.c |  116 +++++++++++++++++++++++++++++++++++++--
 3 files changed, 123 insertions(+), 4 deletions(-)

-- 
1.7.9.5

[PATCH 1/2] watchdog: bcm281xx: Debugfs support

[Markus Mayer]

This change introduces debugfs support for the BCM281xx watchdog driver.

Signed-off-by: Markus Mayer <markus.mayer@linaro.org>
---
 drivers/watchdog/Kconfig        |   10 ++++
 drivers/watchdog/bcm_kona_wdt.c |  116 +++++++++++++++++++++++++++++++++++++--
 2 files changed, 122 insertions(+), 4 deletions(-)

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 10d188a..9b8b96d 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1152,6 +1152,16 @@ config BCM_KONA_WDT
 	  Say 'Y' or 'M' here to enable the driver. The module will be called
 	  bcm_kona_wdt.
 
+config BCM_KONA_WDT_DEBUG
+	bool "DEBUGFS support for BCM Kona Watchdog"
+	depends on BCM_KONA_WDT
+	help
+	  If enabled, adds /sys/kernel/debug/bcm-kona-wdt/info which provides
+	  access to the driver's internal data structures as well as watchdog
+	  timer hardware registres.
+
+	  If in doubt, say 'N'.
+
 config LANTIQ_WDT
 	tristate "Lantiq SoC watchdog"
 	depends on LANTIQ
diff --git a/drivers/watchdog/bcm_kona_wdt.c b/drivers/watchdog/bcm_kona_wdt.c
index 7e41a83..d3aa473 100644
--- a/drivers/watchdog/bcm_kona_wdt.c
+++ b/drivers/watchdog/bcm_kona_wdt.c
@@ -11,6 +11,7 @@
  * GNU General Public License for more details.
  */
 
+#include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/io.h>
@@ -55,9 +56,13 @@ struct bcm_kona_wdt {
 	 */
 	int resolution;
 	spinlock_t lock;
+#ifdef CONFIG_BCM_KONA_WDT_DEBUG
+	unsigned long busy_count;
+	struct dentry *debugfs;
+#endif
 };
 
-static int secure_register_read(void __iomem *addr)
+static int secure_register_read(struct bcm_kona_wdt *wdt, uint32_t offset)
 {
 	uint32_t val;
 	unsigned count = 0;
@@ -70,10 +75,16 @@ static int secure_register_read(void __iomem *addr)
 	do {
 		if (unlikely(count > 1))
 			udelay(5);
-		val = readl_relaxed(addr);
+		val = readl_relaxed(wdt->base + offset);
 		count++;
 	} while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY);
 
+#ifdef CONFIG_BCM_KONA_WDT_DEBUG
+	/* Remember the maximum number iterations due to WD_LOAD_FLAG */
+	if (count > wdt->busy_count)
+		wdt->busy_count = count;
+#endif
+
 	/* This is the only place we return a negative value. */
 	if (val & SECWDOG_WD_LOAD_FLAG)
 		return -ETIMEDOUT;
@@ -84,6 +95,80 @@ static int secure_register_read(void __iomem *addr)
 	return val;
 }
 
+#ifdef CONFIG_BCM_KONA_WDT_DEBUG
+
+static int bcm_kona_wdt_dbg_show(struct seq_file *s, void *data)
+{
+	int ctl_val, cur_val, ret;
+	unsigned long flags;
+	struct bcm_kona_wdt *wdt = s->private;
+
+	if (!wdt)
+		return seq_puts(s, "No device pointer\n");
+
+	spin_lock_irqsave(&wdt->lock, flags);
+	ctl_val = secure_register_read(wdt, SECWDOG_CTRL_REG);
+	cur_val = secure_register_read(wdt, SECWDOG_COUNT_REG);
+	spin_unlock_irqrestore(&wdt->lock, flags);
+
+	if (ctl_val < 0 || cur_val < 0) {
+		ret = seq_puts(s, "Error accessing hardware\n");
+	} else {
+		int ctl, cur, ctl_sec, cur_sec, res;
+
+		ctl = ctl_val & SECWDOG_COUNT_MASK;
+		res = (ctl_val & SECWDOG_RES_MASK) >> SECWDOG_CLKS_SHIFT;
+		cur = cur_val & SECWDOG_COUNT_MASK;
+		ctl_sec = TICKS_TO_SECS(ctl, wdt);
+		cur_sec = TICKS_TO_SECS(cur, wdt);
+		ret = seq_printf(s, "Resolution: %d / %d\n"
+				"Control: %d s / %d (%#x) ticks\n"
+				"Current: %d s / %d (%#x) ticks\n"
+				"Busy count: %lu\n", res,
+				wdt->resolution, ctl_sec, ctl, ctl, cur_sec,
+				cur, cur, wdt->busy_count);
+	}
+
+	return ret;
+}
+
+static int bcm_kona_dbg_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, bcm_kona_wdt_dbg_show, inode->i_private);
+}
+
+static const struct file_operations bcm_kona_dbg_operations = {
+	.open		= bcm_kona_dbg_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static struct dentry *bcm_kona_wdt_debugfs_init(struct bcm_kona_wdt *wdt,
+	struct watchdog_device *wdd)
+{
+	struct dentry *dir;
+
+	dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);
+	if (IS_ERR_OR_NULL(dir))
+		return NULL;
+
+	if (debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,
+				&bcm_kona_dbg_operations))
+		return dir;
+
+	/* Clean up */
+	debugfs_remove_recursive(dir);
+	return NULL;
+}
+
+static void bcm_kona_debugfs_exit(struct dentry *dir)
+{
+	debugfs_remove_recursive(dir);
+}
+
+#endif /* CONFIG_BCM_KONA_WDT_DEBUG */
+
 static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
 					unsigned mask, unsigned newval)
 {
@@ -93,7 +178,7 @@ static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
 
 	spin_lock_irqsave(&wdt->lock, flags);
 
-	val = secure_register_read(wdt->base + SECWDOG_CTRL_REG);
+	val = secure_register_read(wdt, SECWDOG_CTRL_REG);
 	if (val < 0) {
 		ret = val;
 	} else {
@@ -140,7 +225,7 @@ static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)
 	unsigned long flags;
 
 	spin_lock_irqsave(&wdt->lock, flags);
-	val = secure_register_read(wdt->base + SECWDOG_COUNT_REG);
+	val = secure_register_read(wdt, SECWDOG_COUNT_REG);
 	spin_unlock_irqrestore(&wdt->lock, flags);
 
 	if (val < 0)
@@ -190,6 +275,27 @@ static void bcm_kona_wdt_shutdown(struct platform_device *pdev)
 	bcm_kona_wdt_stop(&bcm_kona_wdt_wdd);
 }
 
+#ifdef CONFIG_BCM_KONA_WDT_DEBUG
+static void bcm_kona_wdt_debug_init(struct platform_device *pdev)
+{
+	struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
+
+	wdt->debugfs = bcm_kona_wdt_debugfs_init(wdt, &bcm_kona_wdt_wdd);
+}
+
+static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)
+{
+	struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
+
+	if (wdt->debugfs)
+		bcm_kona_debugfs_exit(wdt->debugfs);
+}
+
+#else
+static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {}
+static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {}
+#endif
+
 static int bcm_kona_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -229,6 +335,7 @@ static int bcm_kona_wdt_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	bcm_kona_wdt_debug_init(pdev);
 	dev_dbg(dev, "Broadcom Kona Watchdog Timer");
 
 	return 0;
@@ -236,6 +343,7 @@ static int bcm_kona_wdt_probe(struct platform_device *pdev)
 
 static int bcm_kona_wdt_remove(struct platform_device *pdev)
 {
+	bcm_kona_wdt_debug_exit(pdev);
 	bcm_kona_wdt_shutdown(pdev);
 	watchdog_unregister_device(&bcm_kona_wdt_wdd);
 	dev_dbg(&pdev->dev, "Watchdog driver disabled");
-- 
1.7.9.5

[PATCH 2/2] watchdog: bcm281xx: Turn on debugfs support for watchdog driver

[Markus Mayer]

This change turns on debugfs support for the BCM281xx watchdog driver.

Signed-off-by: Markus Mayer <markus.mayer@linaro.org>
---
 arch/arm/configs/bcm_defconfig |    1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/configs/bcm_defconfig b/arch/arm/configs/bcm_defconfig
index 10d1392..d4d0083 100644
--- a/arch/arm/configs/bcm_defconfig
+++ b/arch/arm/configs/bcm_defconfig
@@ -128,3 +128,4 @@ CONFIG_XZ_DEC=y
 CONFIG_AVERAGE=y
 CONFIG_WATCHDOG=y
 CONFIG_BCM_KONA_WDT=y
+CONFIG_BCM_KONA_WDT_DEBUG=y
-- 
1.7.9.5

Re: [PATCH 1/2] watchdog: bcm281xx: Debugfs support

[Guenter Roeck]

On 12/31/2013 01:22 PM, Markus Mayer wrote:
> This change introduces debugfs support for the BCM281xx watchdog driver.
>
> Signed-off-by: Markus Mayer <markus.mayer@linaro.org>
> ---
>   drivers/watchdog/Kconfig        |   10 ++++
>   drivers/watchdog/bcm_kona_wdt.c |  116 +++++++++++++++++++++++++++++++++++++--
>   2 files changed, 122 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 10d188a..9b8b96d 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1152,6 +1152,16 @@ config BCM_KONA_WDT
>   	  Say 'Y' or 'M' here to enable the driver. The module will be called
>   	  bcm_kona_wdt.
>
> +config BCM_KONA_WDT_DEBUG
> +	bool "DEBUGFS support for BCM Kona Watchdog"
> +	depends on BCM_KONA_WDT
> +	help
> +	  If enabled, adds /sys/kernel/debug/bcm-kona-wdt/info which provides
> +	  access to the driver's internal data structures as well as watchdog
> +	  timer hardware registres.
> +
Unless Wim already applied this patch, I would suggest to merge the followup patch
with this one.

> +	  If in doubt, say 'N'.
> +
>   config LANTIQ_WDT
>   	tristate "Lantiq SoC watchdog"
>   	depends on LANTIQ
> diff --git a/drivers/watchdog/bcm_kona_wdt.c b/drivers/watchdog/bcm_kona_wdt.c
> index 7e41a83..d3aa473 100644
> --- a/drivers/watchdog/bcm_kona_wdt.c
> +++ b/drivers/watchdog/bcm_kona_wdt.c
> @@ -11,6 +11,7 @@
>    * GNU General Public License for more details.
>    */
>
> +#include <linux/debugfs.h>
>   #include <linux/delay.h>
>   #include <linux/err.h>
>   #include <linux/io.h>
> @@ -55,9 +56,13 @@ struct bcm_kona_wdt {
>   	 */
>   	int resolution;
>   	spinlock_t lock;
> +#ifdef CONFIG_BCM_KONA_WDT_DEBUG
> +	unsigned long busy_count;
> +	struct dentry *debugfs;
> +#endif
>   };
>
> -static int secure_register_read(void __iomem *addr)
> +static int secure_register_read(struct bcm_kona_wdt *wdt, uint32_t offset)
>   {
>   	uint32_t val;
>   	unsigned count = 0;
> @@ -70,10 +75,16 @@ static int secure_register_read(void __iomem *addr)
>   	do {
>   		if (unlikely(count > 1))
>   			udelay(5);
> -		val = readl_relaxed(addr);
> +		val = readl_relaxed(wdt->base + offset);
>   		count++;
>   	} while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY);
>
> +#ifdef CONFIG_BCM_KONA_WDT_DEBUG
> +	/* Remember the maximum number iterations due to WD_LOAD_FLAG */
> +	if (count > wdt->busy_count)
> +		wdt->busy_count = count;
> +#endif
> +
>   	/* This is the only place we return a negative value. */
>   	if (val & SECWDOG_WD_LOAD_FLAG)
>   		return -ETIMEDOUT;
> @@ -84,6 +95,80 @@ static int secure_register_read(void __iomem *addr)
>   	return val;
>   }
>
> +#ifdef CONFIG_BCM_KONA_WDT_DEBUG
> +
> +static int bcm_kona_wdt_dbg_show(struct seq_file *s, void *data)
> +{
> +	int ctl_val, cur_val, ret;
> +	unsigned long flags;
> +	struct bcm_kona_wdt *wdt = s->private;
> +
> +	if (!wdt)
> +		return seq_puts(s, "No device pointer\n");
> +
> +	spin_lock_irqsave(&wdt->lock, flags);
> +	ctl_val = secure_register_read(wdt, SECWDOG_CTRL_REG);
> +	cur_val = secure_register_read(wdt, SECWDOG_COUNT_REG);
> +	spin_unlock_irqrestore(&wdt->lock, flags);
> +
> +	if (ctl_val < 0 || cur_val < 0) {
> +		ret = seq_puts(s, "Error accessing hardware\n");
> +	} else {
> +		int ctl, cur, ctl_sec, cur_sec, res;
> +
> +		ctl = ctl_val & SECWDOG_COUNT_MASK;
> +		res = (ctl_val & SECWDOG_RES_MASK) >> SECWDOG_CLKS_SHIFT;
> +		cur = cur_val & SECWDOG_COUNT_MASK;
> +		ctl_sec = TICKS_TO_SECS(ctl, wdt);
> +		cur_sec = TICKS_TO_SECS(cur, wdt);
> +		ret = seq_printf(s, "Resolution: %d / %d\n"
> +				"Control: %d s / %d (%#x) ticks\n"
> +				"Current: %d s / %d (%#x) ticks\n"
> +				"Busy count: %lu\n", res,
> +				wdt->resolution, ctl_sec, ctl, ctl, cur_sec,
> +				cur, cur, wdt->busy_count);
> +	}
> +
> +	return ret;
> +}
> +
> +static int bcm_kona_dbg_open(struct inode *inode, struct file *file)
> +{
> +	return single_open(file, bcm_kona_wdt_dbg_show, inode->i_private);
> +}
> +
> +static const struct file_operations bcm_kona_dbg_operations = {
> +	.open		= bcm_kona_dbg_open,
> +	.read		= seq_read,
> +	.llseek		= seq_lseek,
> +	.release	= single_release,
> +};
> +
> +static struct dentry *bcm_kona_wdt_debugfs_init(struct bcm_kona_wdt *wdt,
> +	struct watchdog_device *wdd)
> +{
> +	struct dentry *dir;
> +
> +	dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);
> +	if (IS_ERR_OR_NULL(dir))
> +		return NULL;
> +
> +	if (debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,
> +				&bcm_kona_dbg_operations))
> +		return dir;
> +
> +	/* Clean up */
> +	debugfs_remove_recursive(dir);
> +	return NULL;
> +}
> +
> +static void bcm_kona_debugfs_exit(struct dentry *dir)
> +{
> +	debugfs_remove_recursive(dir);
> +}
> +
> +#endif /* CONFIG_BCM_KONA_WDT_DEBUG */
> +
>   static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
>   					unsigned mask, unsigned newval)
>   {
> @@ -93,7 +178,7 @@ static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
>
>   	spin_lock_irqsave(&wdt->lock, flags);
>
> -	val = secure_register_read(wdt->base + SECWDOG_CTRL_REG);
> +	val = secure_register_read(wdt, SECWDOG_CTRL_REG);
>   	if (val < 0) {
>   		ret = val;
>   	} else {
> @@ -140,7 +225,7 @@ static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)
>   	unsigned long flags;
>
>   	spin_lock_irqsave(&wdt->lock, flags);
> -	val = secure_register_read(wdt->base + SECWDOG_COUNT_REG);
> +	val = secure_register_read(wdt, SECWDOG_COUNT_REG);
>   	spin_unlock_irqrestore(&wdt->lock, flags);
>
>   	if (val < 0)
> @@ -190,6 +275,27 @@ static void bcm_kona_wdt_shutdown(struct platform_device *pdev)
>   	bcm_kona_wdt_stop(&bcm_kona_wdt_wdd);
>   }
>
> +#ifdef CONFIG_BCM_KONA_WDT_DEBUG
> +static void bcm_kona_wdt_debug_init(struct platform_device *pdev)
> +{
> +	struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
> +
> +	wdt->debugfs = bcm_kona_wdt_debugfs_init(wdt, &bcm_kona_wdt_wdd);
> +}
> +
> +static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)
> +{
> +	struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
> +
> +	if (wdt->debugfs)
> +		bcm_kona_debugfs_exit(wdt->debugfs);
> +}
> +
> +#else
> +static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {}
> +static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {}
> +#endif
> +

Can you fold those functions into bcm_kona_wdt_debugfs_init() and bcm_kona_debugfs_exit() ?
Then you only need a sinfle #ifdef / #else combination. Only functional change would be to
set wdt->debugfs in bcm_kona_wdt_debugfs_init() and to check it in bcm_kona_debugfs_exit().

Thanks,
Guenter