[PATCH 7/10] watchdog: bcm63xx_wdt: Add get_timeleft function

Simon Arlott
2015-11-22T14:09:20Z

Return the remaining time from the hardware control register.

Warn when the device is registered if the hardware watchdog is currently
running and report the remaining time left.

Signed-off-by: Simon Arlott <simon-A6De1vDTPLDsq35pWSNszA@public.gmane.org>
---
drivers/watchdog/bcm63xx_wdt.c | 38 +++++++++++++++++++++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/bcm63xx_wdt.c b/drivers/watchdog/bcm63xx_wdt.c
index eb5e551..7109eb4 100644
--- a/drivers/watchdog/bcm63xx_wdt.c
+++ b/drivers/watchdog/bcm63xx_wdt.c
@@ -14,6 +14,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/clk.h>
+#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/kernel.h>
@@ -75,6 +76,19 @@ static int bcm63xx_wdt_stop(struct watchdog_device *wdd)
return 0;
}

+static unsigned int bcm63xx_wdt_get_timeleft(struct watchdog_device *wdd)
+{
+ struct bcm63xx_wdt_hw *hw = watchdog_get_drvdata(wdd);
+ unsigned long flags;
+ u32 val;
+
+ raw_spin_lock_irqsave(&hw->lock, flags);
+ val = __raw_readl(hw->regs + WDT_CTL_REG);
+ val /= hw->clock_hz;
+ raw_spin_unlock_irqrestore(&hw->lock, flags);
+ return val;
+}
+
static int bcm63xx_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
@@ -130,6 +144,7 @@ static struct watchdog_ops bcm63xx_wdt_ops = {
.owner = THIS_MODULE,
.start = bcm63xx_wdt_start,
.stop = bcm63xx_wdt_stop,
+ .get_timeleft = bcm63xx_wdt_get_timeleft,
.set_timeout = bcm63xx_wdt_set_timeout,
};

@@ -144,6 +159,8 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
struct bcm63xx_wdt_hw *hw;
struct watchdog_device *wdd;
struct resource *r;
+ u32 timeleft1, timeleft2;
+ unsigned int timeleft;
int ret;

hw = devm_kzalloc(&pdev->dev, sizeof(*hw), GFP_KERNEL);
@@ -182,7 +199,6 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
}

raw_spin_lock_init(&hw->lock);
- hw->running = false;

wdd->parent = &pdev->dev;
wdd->ops = &bcm63xx_wdt_ops;
@@ -197,6 +213,23 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
watchdog_init_timeout(wdd, 0, &pdev->dev);
watchdog_set_nowayout(wdd, nowayout);

+ /* Compare two reads of the time left value, 2 clock ticks apart */
+ rmb();
+ timeleft1 = __raw_readl(hw->regs + WDT_CTL_REG);
+ udelay(DIV_ROUND_UP(1000000, hw->clock_hz / 2));
+ /* Ensure the register is read twice */
+ rmb();
+ timeleft2 = __raw_readl(hw->regs + WDT_CTL_REG);
+
+ /* If the time left is changing, the watchdog is running */
+ if (timeleft1 != timeleft2) {
+ hw->running = true;
+ timeleft = bcm63xx_wdt_get_timeleft(wdd);
+ } else {
+ hw->running = false;
+ timeleft = 0;
+ }
+
ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, wdd);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register wdt timer isr\n");
@@ -214,6 +247,8 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
dev_name(wdd->dev), hw->regs,
wdd->timeout, wdd->max_timeout);

+ if (timeleft > 0)
+ dev_alert(wdd->dev, "running, reboot in %us\n", timeleft);
return 0;

unregister_timer:
@@ -255,6 +290,7 @@ module_platform_driver(bcm63xx_wdt_driver);

MODULE_AUTHOR("Miguel Gaio <miguel.gaio-HH44TBFINEIAvxtiuMwx3w@public.gmane.org>");
MODULE_AUTHOR("Florian Fainelli <florian-p3rKhJxN3npAfugRpC6u6w@public.gmane.org>");
+MODULE_AUTHOR("Simon Arlott");
MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:bcm63xx-wdt");
--
2.1.4

--
Simon Arlott
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in