[PATCH] watchdog: s3c2410_wdt: Report when the watchdog reset the system

Doug Anderson
2013-12-02T18:15:15Z

A good watchdog driver is supposed to report when it was responsible
for resetting the system. Implement this for the s3c2410, at least on
exynos5250 and exynos5420 where we already have a pointer to the PMU
registers to read the information.

Signed-off-by: Doug Anderson <dianders@chromium.org>
---
This patch is based atop Leela Krishna's recent series that ends with
(ARM: dts: update watchdog device nodes for Exynos5250 and Exynos5420)
AKA <https://patchwork.kernel.org/patch/3251861/>.

drivers/watchdog/s3c2410_wdt.c | 42 +++++++++++++++++++++++++++++++++++++++---
1 file changed, 39 insertions(+), 3 deletions(-)

diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index 47f4dcf..2c87d37 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -62,9 +62,13 @@
#define CONFIG_S3C2410_WATCHDOG_ATBOOT (0)
#define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15)

+#define RST_STAT_REG_OFFSET 0x0404
#define WDT_DISABLE_REG_OFFSET 0x0408
#define WDT_MASK_RESET_REG_OFFSET 0x040c
#define QUIRK_NEEDS_PMU_CONFIG (1 << 0)
+#define QUIRK_HAS_RST_STAT (1 << 1)
+#define QUIRKS_NEED_PMUREG (QUIRK_NEEDS_PMU_CONFIG | \
+ QUIRK_HAS_RST_STAT)

static bool nowayout = WATCHDOG_NOWAYOUT;
static int tmr_margin;
@@ -98,6 +102,9 @@ MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug (default 0)");
* timer reset functionality.
* @mask_bit: Bit number for the watchdog timer in the disable register and the
* mask reset register.
+ * @rst_stat_reg: Offset in pmureg for the register that has the reset status.
+ * @rst_stat_bit: Bit number in the rst_stat register indicating a watchdog
+ * reset.
* @quirks: A bitfield of quirks.
*/

@@ -105,6 +112,8 @@ struct s3c2410_wdt_variant {
int disable_reg;
int mask_reset_reg;
int mask_bit;
+ int rst_stat_reg;
+ int rst_stat_bit;
u32 quirks;
};

@@ -131,14 +140,20 @@ static const struct s3c2410_wdt_variant drv_data_exynos5250 = {
.disable_reg = WDT_DISABLE_REG_OFFSET,
.mask_reset_reg = WDT_MASK_RESET_REG_OFFSET,
.mask_bit = 20,
- .quirks = QUIRK_NEEDS_PMU_CONFIG
+ .rst_stat_reg = RST_STAT_REG_OFFSET,
+ .rst_stat_bit = 20,
+ .quirks = QUIRK_NEEDS_PMU_CONFIG |
+ QUIRK_HAS_RST_STAT,
};

static const struct s3c2410_wdt_variant drv_data_exynos5420 = {
.disable_reg = WDT_DISABLE_REG_OFFSET,
.mask_reset_reg = WDT_MASK_RESET_REG_OFFSET,
.mask_bit = 0,
- .quirks = QUIRK_NEEDS_PMU_CONFIG
+ .rst_stat_reg = RST_STAT_REG_OFFSET,
+ .rst_stat_bit = 9,
+ .quirks = QUIRK_NEEDS_PMU_CONFIG |
+ QUIRK_HAS_RST_STAT,
};

static const struct of_device_id s3c2410_wdt_match[] = {
@@ -423,6 +438,25 @@ static inline void s3c2410wdt_cpufreq_deregister(struct s3c2410_wdt *wdt)
}
#endif

+static inline unsigned int s3c2410wdt_get_bootstatus(struct s3c2410_wdt *wdt)
+{
+ unsigned int bootstatus = 0;
+ int ret;
+
+ if (wdt->drv_data->quirks & QUIRK_HAS_RST_STAT) {
+ unsigned int rst_stat;
+
+ ret = regmap_read(wdt->pmureg, wdt->drv_data->rst_stat_reg,
+ &rst_stat);
+ if (ret)
+ dev_warn(wdt->dev, "Couldn't get RST_STAT register\n");
+ else if (rst_stat & BIT(wdt->drv_data->rst_stat_bit))
+ bootstatus |= WDIOF_CARDRESET;
+ }
+
+ return bootstatus;
+}
+
/* s3c2410_get_wdt_driver_data */
static inline struct s3c2410_wdt_variant *
get_wdt_drv_data(struct platform_device *pdev)
@@ -460,7 +494,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
wdt->wdt_device = s3c2410_wdd;

wdt->drv_data = get_wdt_drv_data(pdev);
- if (wdt->drv_data->quirks & QUIRK_NEEDS_PMU_CONFIG) {
+ if (wdt->drv_data->quirks & QUIRKS_NEED_PMUREG) {
wdt->pmureg = syscon_regmap_lookup_by_phandle(dev->of_node,
"samsung,syscon-phandle");
if (IS_ERR(wdt->pmureg)) {
@@ -531,6 +565,8 @@ static int s3c2410wdt_probe(struct platform_device *pdev)

watchdog_set_nowayout(&wdt->wdt_device, nowayout);

+ wdt->wdt_device.bootstatus = s3c2410wdt_get_bootstatus(wdt);
+
ret = watchdog_register_device(&wdt->wdt_device);
if (ret) {
dev_err(dev, "cannot register watchdog (%d)\n", ret);
--
1.8.4.1