diff options
Diffstat (limited to 'kernel/drivers/watchdog/bcm2835_wdt.c')
| -rw-r--r-- | kernel/drivers/watchdog/bcm2835_wdt.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/kernel/drivers/watchdog/bcm2835_wdt.c b/kernel/drivers/watchdog/bcm2835_wdt.c index 2b5a9bbf8..8a5ce5b5a 100644 --- a/kernel/drivers/watchdog/bcm2835_wdt.c +++ b/kernel/drivers/watchdog/bcm2835_wdt.c @@ -13,30 +13,43 @@ * option) any later version. */ +#include <linux/delay.h> +#include <linux/reboot.h> #include <linux/types.h> #include <linux/module.h> #include <linux/io.h> #include <linux/watchdog.h> #include <linux/platform_device.h> #include <linux/of_address.h> +#include <linux/of_platform.h> #define PM_RSTC 0x1c +#define PM_RSTS 0x20 #define PM_WDOG 0x24 #define PM_PASSWORD 0x5a000000 #define PM_WDOG_TIME_SET 0x000fffff #define PM_RSTC_WRCFG_CLR 0xffffffcf +#define PM_RSTS_HADWRH_SET 0x00000040 #define PM_RSTC_WRCFG_SET 0x00000030 #define PM_RSTC_WRCFG_FULL_RESET 0x00000020 #define PM_RSTC_RESET 0x00000102 +/* + * The Raspberry Pi firmware uses the RSTS register to know which partiton + * to boot from. The partiton value is spread into bits 0, 2, 4, 6, 8, 10. + * Partiton 63 is a special partition used by the firmware to indicate halt. + */ +#define PM_RSTS_RASPBERRYPI_HALT 0x555 + #define SECS_TO_WDOG_TICKS(x) ((x) << 16) #define WDOG_TICKS_TO_SECS(x) ((x) >> 16) struct bcm2835_wdt { void __iomem *base; spinlock_t lock; + struct notifier_block restart_handler; }; static unsigned int heartbeat; @@ -106,6 +119,52 @@ static struct watchdog_device bcm2835_wdt_wdd = { .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET), }; +static int +bcm2835_restart(struct notifier_block *this, unsigned long mode, void *cmd) +{ + struct bcm2835_wdt *wdt = container_of(this, struct bcm2835_wdt, + restart_handler); + u32 val; + + /* use a timeout of 10 ticks (~150us) */ + writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG); + val = readl_relaxed(wdt->base + PM_RSTC); + val &= PM_RSTC_WRCFG_CLR; + val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET; + writel_relaxed(val, wdt->base + PM_RSTC); + + /* No sleeping, possibly atomic. */ + mdelay(1); + + return 0; +} + +/* + * We can't really power off, but if we do the normal reset scheme, and + * indicate to bootcode.bin not to reboot, then most of the chip will be + * powered off. + */ +static void bcm2835_power_off(void) +{ + struct device_node *np = + of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt"); + struct platform_device *pdev = of_find_device_by_node(np); + struct bcm2835_wdt *wdt = platform_get_drvdata(pdev); + u32 val; + + /* + * We set the watchdog hard reset bit here to distinguish this reset + * from the normal (full) reset. bootcode.bin will not reboot after a + * hard reset. + */ + val = readl_relaxed(wdt->base + PM_RSTS); + val |= PM_PASSWORD | PM_RSTS_RASPBERRYPI_HALT; + writel_relaxed(val, wdt->base + PM_RSTS); + + /* Continue with normal reset mechanism */ + bcm2835_restart(&wdt->restart_handler, REBOOT_HARD, NULL); +} + static int bcm2835_wdt_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; @@ -129,6 +188,7 @@ static int bcm2835_wdt_probe(struct platform_device *pdev) watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt); watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev); watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout); + bcm2835_wdt_wdd.parent = &pdev->dev; err = watchdog_register_device(&bcm2835_wdt_wdd); if (err) { dev_err(dev, "Failed to register watchdog device"); @@ -136,6 +196,12 @@ static int bcm2835_wdt_probe(struct platform_device *pdev) return err; } + wdt->restart_handler.notifier_call = bcm2835_restart; + wdt->restart_handler.priority = 128; + register_restart_handler(&wdt->restart_handler); + if (pm_power_off == NULL) + pm_power_off = bcm2835_power_off; + dev_info(dev, "Broadcom BCM2835 watchdog timer"); return 0; } @@ -144,6 +210,9 @@ static int bcm2835_wdt_remove(struct platform_device *pdev) { struct bcm2835_wdt *wdt = platform_get_drvdata(pdev); + unregister_restart_handler(&wdt->restart_handler); + if (pm_power_off == bcm2835_power_off) + pm_power_off = NULL; watchdog_unregister_device(&bcm2835_wdt_wdd); iounmap(wdt->base); |