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 <diand...@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
> 
> 
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