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authorStefan Agner <stefan.agner@toradex.com>2013-10-15 11:26:51 +0200
committerStefan Agner <stefan.agner@toradex.com>2013-10-15 11:26:51 +0200
commit5da592b805718b4f33897d642f577b1e6511bc2b (patch)
treea204dcdffbb1e7a2dad080bb8aba61212fec0d47 /drivers/watchdog
parent35412b809534b5fe6572b6c14949594b8053bc84 (diff)
tegra_wdt: support default watchdog api
Reworked driver in order to properly support default watchdog api such as triggering by writing a character and disable by sending a magic character. Renamed ENABLE_ON_PROBE to ENABLE_HEARTBEAT which triggers the watchdog using the interrupt service routine.
Diffstat (limited to 'drivers/watchdog')
-rw-r--r--drivers/watchdog/Kconfig15
-rw-r--r--drivers/watchdog/tegra_wdt.c200
2 files changed, 150 insertions, 65 deletions
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 9a94f7e093dd..8d41441b05ed 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -217,17 +217,20 @@ config TEGRA_WATCHDOG
depends on ARCH_TEGRA
help
Say Y here to include support for the watchdog timer
- embedded in NVIDIA Tegra SoCs.
+ embedded in NVIDIA Tegra SoCs. The default timeout
+ is set to 60 seconds.
To compile this driver as a module, choose M here: the
module will be called tegra_wdt.
-config TEGRA_WATCHDOG_ENABLE_ON_PROBE
- tristate "Turn on Tegra watchdog at system start up"
- depends on ARCH_TEGRA && TEGRA_WATCHDOG
+config TEGRA_WATCHDOG_ENABLE_HEARTBEAT
+ bool "Use the first Tegra watchdog as kernel heartbeats"
+ depends on TEGRA_WATCHDOG
+ default n
help
- Say Y here to enable the tegra watchdog at driver
- probe time, rather than when the device is opened.
+ Say Y here to enable the first tegra watchdog at driver
+ probe time. The kernel will reload the watchdog by
+ itself in an interrupt handler.
config EP93XX_WATCHDOG
tristate "EP93xx Watchdog"
diff --git a/drivers/watchdog/tegra_wdt.c b/drivers/watchdog/tegra_wdt.c
index 1bcd726ebbd6..d32c516b2c55 100644
--- a/drivers/watchdog/tegra_wdt.c
+++ b/drivers/watchdog/tegra_wdt.c
@@ -4,6 +4,7 @@
* watchdog driver for NVIDIA tegra internal watchdog
*
* Copyright (c) 2012, NVIDIA Corporation.
+ * Copyright (c) 2013, Toradex AG
*
* based on drivers/watchdog/softdog.c and drivers/watchdog/omap_wdt.c
*
@@ -42,13 +43,33 @@
/* minimum and maximum watchdog trigger periods, in seconds */
#define MIN_WDT_PERIOD 5
#define MAX_WDT_PERIOD 1000
+
/* Assign Timer 7 to Timer 10 for WDT0 to WDT3, respectively */
#define TMR_SRC_START 7
+/*
+ * For spinlock lockup detection to work, the heartbeat should be 2*lockup
+ * for cases where the spinlock disabled irqs.
+ * Must be between MIN_WDT_PERIOD and MAX_WDT_PERIOD
+ */
+#define WDT_DEFAULT_TIME 60
+
+static int heartbeat = WDT_DEFAULT_TIME;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds (default="
+ __MODULE_STRING(WDT_DEFAULT_TIME));
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+#endif
enum tegra_wdt_status {
WDT_DISABLED = 1 << 0,
WDT_ENABLED = 1 << 1,
- WDT_ENABLED_AT_PROBE = 1 << 2,
+ WDT_KERNEL_HEARTBEAT = 1 << 2,
};
struct tegra_wdt {
@@ -61,18 +82,15 @@ struct tegra_wdt {
void __iomem *wdt_source;
void __iomem *wdt_timer;
void __iomem *int_base;
- int irq;
int tmrsrc;
int timeout;
int status;
+ int way_out_ok;
+ struct tasklet_struct tasklet;
+ int irq;
+ int irq_counter;
};
-/*
- * For spinlock lockup detection to work, the heartbeat should be 2*lockup
- * for cases where the spinlock disabled irqs.
- */
-static int heartbeat = 120; /* must be greater than MIN_WDT_PERIOD and lower than MAX_WDT_PERIOD */
-
#if defined(CONFIG_ARCH_TEGRA_2x_SOC)
#define TIMER_PTV 0x0
@@ -107,6 +125,16 @@ static void tegra_wdt_disable(struct tegra_wdt *wdt)
static inline void tegra_wdt_ping(struct tegra_wdt *wdt)
{
+ /* Reset timer */
+ tegra_wdt_enable(wdt);
+
+ /* Reenable IRQ in case an interrupt already happend */
+ if (wdt->irq_counter) {
+ writel(TIMER_PCR_INTR, wdt->wdt_timer + TIMER_PCR);
+ wdt->irq_counter = 0;
+ enable_irq(wdt->irq);
+ }
+
return;
}
@@ -114,9 +142,30 @@ static irqreturn_t tegra_wdt_interrupt(int irq, void *dev_id)
{
struct tegra_wdt *wdt = dev_id;
- writel(TIMER_PCR_INTR, wdt->wdt_timer + TIMER_PCR);
+ wdt->irq_counter++;
+
+ if (wdt->status & WDT_KERNEL_HEARTBEAT) {
+ tegra_wdt_ping(wdt);
+ } else {
+ /* If not in heartbeat mode, disable IRQs to avoid IRQ storm
+ * We don't acknowledge the interrupt here since the user
+ * did not reload the timer in time. Upon next interrupt
+ * the system will reset...
+ */
+ tasklet_schedule(&wdt->tasklet);
+ disable_irq_nosync(irq);
+ }
+
return IRQ_HANDLED;
}
+
+static void tegra_wdt_do_tasklet(unsigned long data)
+{
+ struct tegra_wdt *wdt = (struct tegra_wdt *)data;
+ dev_info(wdt->miscdev.parent, "Watchdog interrupt received, system "
+ "will reset soon if no ping arrives\n");
+}
+
#elif defined(CONFIG_ARCH_TEGRA_3x_SOC)
#define TIMER_PTV 0
@@ -132,6 +181,7 @@ static irqreturn_t tegra_wdt_interrupt(int irq, void *dev_id)
#define WDT_CFG_PMC2CAR_RST_EN (1 << 15)
#define WDT_STATUS (4)
#define WDT_INTR_STAT (1 << 1)
+ #define WDT_STATUS_EXPIR_COUNTER (3 << 12)
#define WDT_CMD (8)
#define WDT_CMD_START_COUNTER (1 << 0)
#define WDT_CMD_DISABLE_COUNTER (1 << 1)
@@ -169,19 +219,21 @@ static void tegra_wdt_enable(struct tegra_wdt *wdt)
val |= (TIMER_EN | TIMER_PERIODIC);
writel(val, wdt->wdt_timer + TIMER_PTV);
- /* Interrupt handler is not required for user space
- * WDT accesses, since the caller is responsible to ping the
- * WDT to reset the counter before expiration, through ioctls.
+ writel(WDT_CMD_START_COUNTER, wdt->wdt_source + WDT_CMD);
+
+ /* Interrupt handler is not required for user space since
+ * a warning in a fourth of time don't make sense. Then
+ * the interrupt line is also shared, so it can't be disabled
+ * if one watchdog is about to expire... (interrupt storm)
* SYS_RST_EN doesnt work as there is no external reset
* from Tegra.
*/
- val = wdt->tmrsrc | WDT_CFG_PERIOD | /*WDT_CFG_INT_EN |*/
+ val = wdt->tmrsrc | WDT_CFG_PERIOD | /* WDT_CFG_INT_EN | */
/*WDT_CFG_SYS_RST_EN |*/ WDT_CFG_PMC2CAR_RST_EN;
#ifdef CONFIG_TEGRA_FIQ_DEBUGGER
val |= WDT_CFG_FIQ_INT_EN;
#endif
writel(val, wdt->wdt_source + WDT_CFG);
- writel(WDT_CMD_START_COUNTER, wdt->wdt_source + WDT_CMD);
}
static void tegra_wdt_disable(struct tegra_wdt *wdt)
@@ -192,17 +244,30 @@ static void tegra_wdt_disable(struct tegra_wdt *wdt)
writel(0, wdt->wdt_timer + TIMER_PTV);
}
+static void tegra_wdt_interrupt_instance(struct tegra_wdt *wdt)
+{
+ WARN_ON_ONCE(!(wdt->status & WDT_KERNEL_HEARTBEAT));
+
+ if (wdt->status & WDT_KERNEL_HEARTBEAT) {
+ tegra_wdt_ping(wdt);
+ }
+}
+
static irqreturn_t tegra_wdt_interrupt(int irq, void *dev_id)
{
+ struct tegra_wdt *wdt = NULL;
unsigned i, status;
for (i = 0; i < MAX_NR_CPU_WDT; i++) {
- if (tegra_wdt[i] == NULL)
+ wdt = tegra_wdt[i];
+ if (wdt == NULL)
continue;
- status = readl(tegra_wdt[i]->wdt_source + WDT_STATUS);
- if ((tegra_wdt[i]->status & WDT_ENABLED) &&
- (status & WDT_INTR_STAT))
- tegra_wdt_ping(tegra_wdt[i]);
+ status = readl(wdt->wdt_source + WDT_STATUS);
+ if ((wdt->status & WDT_ENABLED) &&
+ (status & WDT_INTR_STAT))
+ {
+ tegra_wdt_interrupt_instance(wdt);
+ }
}
return IRQ_HANDLED;
@@ -228,6 +293,9 @@ static int tegra_wdt_open(struct inode *inode, struct file *file)
if (test_and_set_bit(1, &wdt->users))
return -EBUSY;
+ /* Reset no way out, we need a new magic again */
+ wdt->way_out_ok = 0;
+
wdt->status |= WDT_ENABLED;
wdt->timeout = heartbeat;
tegra_wdt_enable(wdt);
@@ -239,13 +307,19 @@ static int tegra_wdt_release(struct inode *inode, struct file *file)
{
struct tegra_wdt *wdt = file->private_data;
- if (wdt->status == WDT_ENABLED) {
-#ifndef CONFIG_WATCHDOG_NOWAYOUT
- tegra_wdt_disable(wdt);
- wdt->status = WDT_DISABLED;
-#endif
+ if (wdt->status & WDT_ENABLED && !nowayout) {
+ if (wdt->way_out_ok) {
+ tegra_wdt_disable(wdt);
+ wdt->status = WDT_DISABLED;
+ } else {
+ dev_info(wdt->miscdev.parent, "No Magic Close "
+ "received, watchdog not disabled!\n");
+ }
+ } else if (nowayout) {
+ dev_info(wdt->miscdev.parent, "No way out is "
+ "enabled, watchdog not disabled!\n");
}
- wdt->users = 0;
+ clear_bit(1, &wdt->users);
return 0;
}
@@ -288,11 +362,10 @@ static long tegra_wdt_ioctl(struct file *file, unsigned int cmd,
return put_user(wdt->timeout, (int __user *)arg);
case WDIOC_SETOPTIONS:
-#ifndef CONFIG_WATCHDOG_NOWAYOUT
if (get_user(option, (int __user *)arg))
return -EFAULT;
spin_lock(&lock);
- if (option & WDIOS_DISABLECARD) {
+ if (option & WDIOS_DISABLECARD && !nowayout) {
wdt->status &= ~WDT_ENABLED;
wdt->status |= WDT_DISABLED;
tegra_wdt_disable(wdt);
@@ -306,9 +379,6 @@ static long tegra_wdt_ioctl(struct file *file, unsigned int cmd,
}
spin_unlock(&lock);
return 0;
-#else
- return -EINVAL;
-#endif
}
return -ENOTTY;
}
@@ -316,6 +386,19 @@ static long tegra_wdt_ioctl(struct file *file, unsigned int cmd,
static ssize_t tegra_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
+ struct tegra_wdt *wdt = file->private_data;
+
+ /* check if way-out char was written as last data */
+ char c;
+ if(len) {
+ tegra_wdt_ping(wdt);
+
+ if(get_user(c, data + len - 1))
+ return -EFAULT;
+ else
+ wdt->way_out_ok = (('V' == c) ? 1 : 0);
+ }
+
return len;
}
@@ -333,8 +416,14 @@ static int tegra_wdt_probe(struct platform_device *pdev)
struct resource *res_src, *res_wdt, *res_irq;
struct resource *res_int_base = NULL;
struct tegra_wdt *wdt;
- u32 src;
int ret = 0;
+#ifdef CONFIG_TEGRA_WATCHDOG_ENABLE_HEARTBEAT
+#ifdef CONFIG_ARCH_TEGRA_2x_SOC
+ int is_heartbeat_wdt = 1;
+#else
+ int is_heartbeat_wdt = !(pdev->id);
+#endif
+#endif
if (pdev->id < -1 && pdev->id > 3) {
dev_err(&pdev->dev, "only IDs 3:0 supported\n");
@@ -369,7 +458,6 @@ static int tegra_wdt_probe(struct platform_device *pdev)
return -ENOMEM;
}
- wdt->irq = -1;
wdt->miscdev.parent = &pdev->dev;
if (pdev->id == -1) {
wdt->miscdev.minor = WATCHDOG_MINOR;
@@ -410,12 +498,17 @@ static int tegra_wdt_probe(struct platform_device *pdev)
goto fail;
}
- src = readl(wdt->wdt_source);
- if (src & BIT(12))
+#ifdef CONFIG_ARCH_TEGRA_2x_SOC
+ /* Watchdog of Tegra 3 are not at the reset controller regs */
+ if (readl(wdt->wdt_source) & BIT(12))
dev_info(&pdev->dev, "last reset due to watchdog timeout\n");
+#endif
tegra_wdt_disable(wdt);
writel(TIMER_PCR_INTR, wdt->wdt_timer + TIMER_PCR);
+#ifndef CONFIG_ARCH_TEGRA_2x_SOC
+ writel(WDT_CMD_START_COUNTER, wdt->wdt_source + WDT_CMD);
+#endif
if (res_irq != NULL) {
#ifdef CONFIG_TEGRA_FIQ_DEBUGGER
@@ -436,6 +529,7 @@ static int tegra_wdt_probe(struct platform_device *pdev)
goto fail;
tegra_wdt_int_priority(wdt);
#endif
+ wdt->irq = -1;
ret = request_irq(res_irq->start, tegra_wdt_interrupt,
IRQF_DISABLED, dev_name(&pdev->dev), wdt);
if (ret) {
@@ -464,24 +558,26 @@ static int tegra_wdt_probe(struct platform_device *pdev)
}
platform_set_drvdata(pdev, wdt);
+#ifdef CONFIG_ARCH_TEGRA_2x_SOC
+ tasklet_init(&wdt->tasklet, tegra_wdt_do_tasklet, (unsigned long)wdt);
+#endif
-#ifndef CONFIG_ARCH_TEGRA_2x_SOC
-#ifdef CONFIG_TEGRA_WATCHDOG_ENABLE_ON_PROBE
- /* Init and enable watchdog on WDT0 with timer 8 during probe */
- if (!(pdev->id)) {
- u32 val = 0;
- wdt->status = WDT_ENABLED | WDT_ENABLED_AT_PROBE;
+#ifdef CONFIG_TEGRA_WATCHDOG_ENABLE_HEARTBEAT
+ /* Enable first watchdog during probe */
+ if (is_heartbeat_wdt) {
+ wdt->status = WDT_ENABLED | WDT_KERNEL_HEARTBEAT;
wdt->timeout = heartbeat;
+ set_bit(1, &wdt->users);
tegra_wdt_enable(wdt);
- val = readl(wdt->wdt_source + WDT_CFG);
- val |= WDT_CFG_INT_EN;
- writel(val, wdt->wdt_source + WDT_CFG);
- pr_info("WDT heartbeat enabled on probe\n");
+ pr_info("WDT kernel heartbeat enabled on probe\n");
}
#endif
+
+#ifndef CONFIG_ARCH_TEGRA_2x_SOC
tegra_wdt[pdev->id] = wdt;
#endif
- pr_info("%s done\n", __func__);
+
+ dev_info(&pdev->dev, "%s done\n", __func__);
return 0;
fail:
if (wdt->irq != -1)
@@ -543,16 +639,6 @@ static int tegra_wdt_resume(struct platform_device *pdev)
if (wdt->status & WDT_ENABLED)
tegra_wdt_enable(wdt);
-#ifndef CONFIG_ARCH_TEGRA_2x_SOC
- /* Enable interrupt for WDT3 heartbeat watchdog */
- if (wdt->status & WDT_ENABLED_AT_PROBE) {
- u32 val = 0;
- val = readl(wdt->wdt_source + WDT_CFG);
- val |= WDT_CFG_INT_EN;
- writel(val, wdt->wdt_source + WDT_CFG);
- pr_info("WDT heartbeat enabled on probe\n");
- }
-#endif
return 0;
}
#endif
@@ -586,10 +672,6 @@ module_exit(tegra_wdt_exit);
MODULE_AUTHOR("NVIDIA Corporation");
MODULE_DESCRIPTION("Tegra Watchdog Driver");
-module_param(heartbeat, int, 0);
-MODULE_PARM_DESC(heartbeat,
- "Watchdog heartbeat period in seconds");
-
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:tegra_wdt");