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watchdog: bcm2835_wdt: set WDOG_HW_RUNNING bit when appropriate 

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 <rasmus.villemoes@prevas.dk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Rasmus Villemoes 2016-12-12 10:48:43 +01:00 committed by Guenter Roeck
parent 1d8565ee4f
commit 054ae19422
1 changed files with 20 additions and 0 deletions
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20
drivers/watchdog/bcm2835_wdt.c
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@ -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");