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

Guenter Roeck
2013-12-02T20:21:33Z

On Mon, Dec 02, 2013 at 10:14:41AM -0800, Doug Anderson wrote:
> 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)
>
I am not really happy about the NEED (both of them, really) here.
How about HAS instead ?

> 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,

Why not use QUIRKS_NEED_PMUREG ?

Also, is there ever a chance that the two bits don't come together ?
If not a single bit might be sufficient.

Thanks,
Guenter

> };
>
> 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
>
>