[PATCH v2 1/2] watchdog: bcm281xx: Debugfs support
From: Markus Mayer
Date: Mon Jan 06 2014 - 16:56:48 EST
This change introduces debugfs support for the BCM281xx watchdog driver.
Signed-off-by: Markus Mayer <markus.mayer@xxxxxxxxxx>
---
drivers/watchdog/Kconfig | 10 ++++
drivers/watchdog/bcm_kona_wdt.c | 108 +++++++++++++++++++++++++++++++++++++--
2 files changed, 114 insertions(+), 4 deletions(-)
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 10d188a..af8f7c7 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..9c24809 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 +95,93 @@ 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 void bcm_kona_wdt_debug_init(struct platform_device *pdev)
+{
+ struct dentry *dir;
+ struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
+
+ if (!wdt)
+ return;
+
+ wdt->debugfs = NULL;
+
+ dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);
+ if (IS_ERR_OR_NULL(dir))
+ return;
+
+ if (debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,
+ &bcm_kona_dbg_operations))
+ wdt->debugfs = dir;
+ else
+ debugfs_remove_recursive(dir);
+}
+
+static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)
+{
+ struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
+
+ if (wdt && wdt->debugfs) {
+ debugfs_remove_recursive(wdt->debugfs);
+ wdt->debugfs = NULL;
+ }
+}
+
+#else
+
+static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {}
+static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {}
+
+#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 +191,7 @@ 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 +238,7 @@ 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)
@@ -229,6 +327,7 @@ 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 +335,7 @@ 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
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