From: Domenico Andreoli <domenico.andreoli@xxxxxxxxx>
Proof of concept: sp805 as provider of reset hooks.
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Olof Johansson <olof@xxxxxxxxx>
Cc: Wim Van Sebroeck <wim@xxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Domenico Andreoli <domenico.andreoli@xxxxxxxxx>
---
drivers/watchdog/Kconfig | 9 ++++++++
drivers/watchdog/sp805_wdt.c | 48 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 57 insertions(+)
Index: b/drivers/watchdog/Kconfig
===================================================================
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -110,11 +110,20 @@ config WM8350_WATCHDOG
config ARM_SP805_WATCHDOG
tristate "ARM SP805 Watchdog"
depends on ARM && ARM_AMBA
+ select MACHINE_RESET
select WATCHDOG_CORE
help
ARM Primecell SP805 Watchdog timer. This will reboot your system when
the timeout is reached.
+config ARM_SP805_WATCHDOG_RESTART_HOOK
+ bool "ARM SP805 system restart hook"
+ depends on ARM_SP805_WATCHDOG
+ help
+ Register hook to reboot the system based on the SP805 Watchdog.
+
+ This can be overriden with cmdline option restart_hook=0.
+
config AT91RM9200_WATCHDOG
tristate "AT91RM9200 watchdog"
depends on ARCH_AT91RM9200
Index: b/drivers/watchdog/sp805_wdt.c
===================================================================
--- a/drivers/watchdog/sp805_wdt.c
+++ b/drivers/watchdog/sp805_wdt.c
@@ -28,6 +28,8 @@
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/watchdog.h>
+#include <linux/machine_reset.h>
+#include <linux/delay.h>
/* default timeout in seconds */
#define DEFAULT_TIMEOUT 60
@@ -77,6 +79,11 @@ module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Set to 1 to keep watchdog running after device release");
+static bool restart_hook = IS_ENABLED(CONFIG_ARM_SP805_WATCHDOG_RESTART_HOOK);
+module_param(restart_hook, bool, 0);
+MODULE_PARM_DESC(restart_hook,
+ "Set to 1 to install a machine restart handler based on this watchdog");
+
/* This routine finds load value that will reset system in required timout */
static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
{
@@ -189,6 +196,33 @@ static int wdt_disable(struct watchdog_d
return 0;
}
+/* trigger watchdog timer */
+static void wdt_atomic_trigger(struct watchdog_device *wdd)
+{
+ struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ spin_lock(&wdt->lock);
+
+ writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
+ writel_relaxed(0, wdt->base + WDTCONTROL);
+ udelay(20);
+ writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
+ udelay(20);
+
+ /* Expire after 5 cycles */
+ writel_relaxed(5, wdt->base + WDTLOAD);
+
+ writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base + WDTCONTROL);
+ writel_relaxed(LOCK, wdt->base + WDTLOCK);
+
+ /* Flush posted writes. */
+ readl_relaxed(wdt->base + WDTLOCK);
+ spin_unlock(&wdt->lock);
+
+ /* Wait the bite */
+ udelay(400);
+}
+
static const struct watchdog_info wdt_info = {
.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = MODULE_NAME,
@@ -201,8 +235,15 @@ static const struct watchdog_ops wdt_ops
.ping = wdt_ping,
.set_timeout = wdt_setload,
.get_timeleft = wdt_timeleft,
+/* .atomic_trigger = wdt_atomic_trigger, */
};
+static void sp805_wdt_machine_restart(void *wdd, enum reboot_mode mode,
+ const char *cmd)
+{
+ wdt_atomic_trigger(wdd);
+}
+
static int
sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
{
@@ -247,6 +288,13 @@ sp805_wdt_probe(struct amba_device *adev
watchdog_set_drvdata(&wdt->wdd, wdt);
wdt_setload(&wdt->wdd, DEFAULT_TIMEOUT);
+ if (restart_hook) {
+ struct reset_hook hook;
+ reset_hook_init(&hook);
+ hook.restart = sp805_wdt_machine_restart;
+ set_machine_reset(RESET_RESTART, &hook, &wdt->wdd);
+ }
+
ret = watchdog_register_device(&wdt->wdd);
if (ret) {
dev_err(&adev->dev, "watchdog_register_device() failed: %d\n",
--
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