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Diffstat (limited to 'kernel/drivers/watchdog/bcm2835_wdt.c')
-rw-r--r--kernel/drivers/watchdog/bcm2835_wdt.c69
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);