[PATCH (v4) 8/11] watchdog: bcm63xx_wdt: Warn if the watchdog is currently running

Simon Arlott
2015-11-25T22:57:12Z

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>
---
On 25/11/15 02:51, Guenter Roeck wrote:
> This is really two logical changes, isn't it ?

Patch 7 split into two patches.

drivers/watchdog/bcm63xx_wdt.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/bcm63xx_wdt.c b/drivers/watchdog/bcm63xx_wdt.c
index ab4a794..2312dc2 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>
@@ -159,6 +160,8 @@ 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);
@@ -199,7 +202,6 @@ 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;
@@ -213,6 +215,23 @@ 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 = watchdog_register_device(wdd);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register watchdog device\n");
@@ -230,6 +249,8 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
dev_name(wdd->dev), hw->regs,
wdd->timeout, wdd->max_timeout);

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

unregister_watchdog:
--
2.1.4