Hi,
The subject prefix is not correct, it should be rtc: ds1307:
Also, shouldn't that kind of software timeout which doesn't actually
depend on the hardware better be handled in the watchdog core? Then this
will benefit all the watchdog and will certainly avoid a lot of code
duplication.
On 04/08/2020 17:17:43+1200, Mark Tomlinson wrote:
> If the hardware watchdog in the clock chip simply pulls the reset line
> of the CPU, then there is no chance to write a stack trace to help
> determine what may have been blocking the CPU.
>
> This patch adds a pretimeout to the watchdog, which, if enabled, sets
> a timer to go off before the hardware watchdog kicks in, and calls
> the standard pretimeout function, which can (for example) call panic.
>
> Signed-off-by: Mark Tomlinson <mark.tomlin...@alliedtelesis.co.nz>
> ---
> drivers/rtc/rtc-ds1307.c | 35 ++++++++++++++++++++++++++++++++++-
> 1 file changed, 34 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
> index 49702942bb08..647f8659d0bd 100644
> --- a/drivers/rtc/rtc-ds1307.c
> +++ b/drivers/rtc/rtc-ds1307.c
> @@ -23,6 +23,7 @@
> #include <linux/clk-provider.h>
> #include <linux/regmap.h>
> #include <linux/watchdog.h>
> +#include <linux/timer.h>
>
> /*
> * We can't determine type by probing, but if we expect pre-Linux code
> @@ -174,6 +175,10 @@ struct ds1307 {
> #ifdef CONFIG_COMMON_CLK
> struct clk_hw clks[2];
> #endif
> +#ifdef CONFIG_WATCHDOG_CORE
> + struct timer_list soft_timer;
> + struct watchdog_device *wdt;
> +#endif
> };
>
> struct chip_desc {
> @@ -863,12 +868,34 @@ static int m41txx_rtc_set_offset(struct device *dev,
> long offset)
> }
>
> #ifdef CONFIG_WATCHDOG_CORE
> +static void ds1388_soft_wdt_expire(struct timer_list *soft_timer)
> +{
> + struct ds1307 *ds1307 = container_of(soft_timer, struct ds1307,
> soft_timer);
> +
> + watchdog_notify_pretimeout(ds1307->wdt);
> +}
> +
> +static void ds1388_soft_timer_set(struct watchdog_device *wdt_dev)
> +{
> + struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
> + int soft_timeout;
> +
> + if (wdt_dev->pretimeout > 0) {
> + soft_timeout = wdt_dev->timeout - wdt_dev->pretimeout;
> + mod_timer(&ds1307->soft_timer, jiffies + soft_timeout * HZ);
> + } else {
> + del_timer(&ds1307->soft_timer);
> + }
> +}
> +
> static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
> {
> struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
> u8 regs[2];
> int ret;
>
> + ds1388_soft_timer_set(wdt_dev);
> +
> ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
> DS1388_BIT_WF, 0);
> if (ret)
> @@ -900,6 +927,7 @@ static int ds1388_wdt_stop(struct watchdog_device
> *wdt_dev)
> {
> struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
>
> + del_timer(&ds1307->soft_timer);
> return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
> DS1388_BIT_WDE | DS1388_BIT_RST, 0);
> }
> @@ -909,6 +937,7 @@ static int ds1388_wdt_ping(struct watchdog_device
> *wdt_dev)
> struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
> u8 regs[2];
>
> + ds1388_soft_timer_set(wdt_dev);
> return regmap_bulk_read(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
> sizeof(regs));
> }
> @@ -923,6 +952,7 @@ static int ds1388_wdt_set_timeout(struct watchdog_device
> *wdt_dev,
> regs[0] = 0;
> regs[1] = bin2bcd(wdt_dev->timeout);
>
> + ds1388_soft_timer_set(wdt_dev);
> return regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
> sizeof(regs));
> }
> @@ -1652,7 +1682,8 @@ static void ds1307_clks_register(struct ds1307 *ds1307)
>
> #ifdef CONFIG_WATCHDOG_CORE
> static const struct watchdog_info ds1388_wdt_info = {
> - .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
> + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
> + WDIOF_MAGICCLOSE | WDIOF_PRETIMEOUT,
> .identity = "DS1388 watchdog",
> };
>
> @@ -1681,6 +1712,8 @@ static void ds1307_wdt_register(struct ds1307 *ds1307)
> wdt->timeout = 99;
> wdt->max_timeout = 99;
> wdt->min_timeout = 1;
> + ds1307->wdt = wdt;
> + timer_setup(&ds1307->soft_timer, ds1388_soft_wdt_expire, 0);
>
> watchdog_init_timeout(wdt, 0, ds1307->dev);
> watchdog_set_drvdata(wdt, ds1307);
> --
> 2.28.0
>
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
