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

Doug Anderson
2013-12-05T18:16:23Z

Guenter,

On Thu, Dec 5, 2013 at 8:40 AM, Guenter Roeck <linux@roeck-us.net> wrote:
> On Thu, Dec 05, 2013 at 05:21:47PM +0100, Tomasz Figa wrote:
>> 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.
>>
>
> nit: If so, it would make sense to to the same for the other 'quirk'
> for consistency.
>
> static int s3c2410wdt_mask_and_disable_reset(struct s3c2410_wdt *wdt, bool mask)
> {
> ...
> if (!(wdt->drv_data->quirks & QUIRK_NEEDS_PMU_CONFIG))
> return 0;
> ...
> }

Done in my proposed fixup for Leela Krishna's patch.

-Doug