A bootloader may start the watchdog device before handing control to
the kernel - in that case, we should tell the kernel about it so the
watchdog framework can keep it alive until userspace opens
/dev/watchdog0.
Signed-off-by: Rasmus Villemoes <[email protected]>
---
drivers/watchdog/bcm2835_wdt.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c
index 4dddd82..c32c45b 100644
--- a/drivers/watchdog/bcm2835_wdt.c
+++ b/drivers/watchdog/bcm2835_wdt.c
@@ -55,6 +55,15 @@ struct bcm2835_wdt {
static unsigned int heartbeat;
static bool nowayout = WATCHDOG_NOWAYOUT;
+static bool bcm2835_wdt_is_running(struct bcm2835_wdt *wdt)
+{
+ uint32_t cur;
+
+ cur = readl(wdt->base + PM_RSTC);
+
+ return !!(cur & PM_RSTC_WRCFG_FULL_RESET);
+}
+
static int bcm2835_wdt_start(struct watchdog_device *wdog)
{
struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
@@ -181,6 +190,17 @@ static int bcm2835_wdt_probe(struct platform_device *pdev)
watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
bcm2835_wdt_wdd.parent = &pdev->dev;
+ if (bcm2835_wdt_is_running(wdt)) {
+ /*
+ * The currently active timeout value (set by the
+ * bootloader) may be different from the module
+ * heartbeat parameter or the value in device
+ * tree. But we just need to set WDOG_HW_RUNNING,
+ * because then the framework will "immediately" ping
+ * the device, updating the timeout.
+ */
+ set_bit(WDOG_HW_RUNNING, &bcm2835_wdt_wdd.status);
+ }
err = watchdog_register_device(&bcm2835_wdt_wdd);
if (err) {
dev_err(dev, "Failed to register watchdog device");
--
2.7.4
On 12/12/2016 01:48 AM, Rasmus Villemoes wrote:
> A bootloader may start the watchdog device before handing control to
> the kernel - in that case, we should tell the kernel about it so the
> watchdog framework can keep it alive until userspace opens
> /dev/watchdog0.
>
> Signed-off-by: Rasmus Villemoes <[email protected]>
Reviewed-by: Guenter Roeck <[email protected]>
> ---
> drivers/watchdog/bcm2835_wdt.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c
> index 4dddd82..c32c45b 100644
> --- a/drivers/watchdog/bcm2835_wdt.c
> +++ b/drivers/watchdog/bcm2835_wdt.c
> @@ -55,6 +55,15 @@ struct bcm2835_wdt {
> static unsigned int heartbeat;
> static bool nowayout = WATCHDOG_NOWAYOUT;
>
> +static bool bcm2835_wdt_is_running(struct bcm2835_wdt *wdt)
> +{
> + uint32_t cur;
> +
> + cur = readl(wdt->base + PM_RSTC);
> +
> + return !!(cur & PM_RSTC_WRCFG_FULL_RESET);
> +}
> +
> static int bcm2835_wdt_start(struct watchdog_device *wdog)
> {
> struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
> @@ -181,6 +190,17 @@ static int bcm2835_wdt_probe(struct platform_device *pdev)
> watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
> watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
> bcm2835_wdt_wdd.parent = &pdev->dev;
> + if (bcm2835_wdt_is_running(wdt)) {
> + /*
> + * The currently active timeout value (set by the
> + * bootloader) may be different from the module
> + * heartbeat parameter or the value in device
> + * tree. But we just need to set WDOG_HW_RUNNING,
> + * because then the framework will "immediately" ping
> + * the device, updating the timeout.
> + */
> + set_bit(WDOG_HW_RUNNING, &bcm2835_wdt_wdd.status);
> + }
> err = watchdog_register_device(&bcm2835_wdt_wdd);
> if (err) {
> dev_err(dev, "Failed to register watchdog device");
>
Rasmus Villemoes <[email protected]> writes:
> A bootloader may start the watchdog device before handing control to
> the kernel - in that case, we should tell the kernel about it so the
> watchdog framework can keep it alive until userspace opens
> /dev/watchdog0.
I don't believe our current bootloaders (the closed firmware or u-boot)
set up the watchdog, but this seems reasonable since they might want to
later.
Acked-by: Eric Anholt <[email protected]>