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

Tomasz Figa
2013-12-05T16:22:01Z

Hi Doug,

Please see my comments inline.

On Monday 02 of December 2013 10:14:41 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

IMHO this should be namespaced, at least with EXYNOS5 prefix. The two
registers below should be as well, but I missed this in the patch adding
them.

> #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) {

nit: I guess it's just a matter of taste, but to reduce code indentation
you could inverse the check and simply return 0 here.

Best regards,
Tomasz