Re: [RFT PATCH v7 6/9] watchdog: imx2: Convert to use infrastructure triggered keepalives

From: Guenter Roeck
Date: Fri Jan 29 2016 - 14:40:59 EST

On 01/25/2016 06:53 PM, Guenter Roeck wrote:
From: Guenter Roeck <linux@xxxxxxxxxxxx>

The watchdog infrastructure now supports handling watchdog keepalive
if the watchdog is running while the watchdog device is closed.
Convert the driver to use this infrastructure.

Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>

I managed to test this patch with qemu (after implementing the imx2 watchdog
in qemu). It works as expected, so please consider it upgraded from RFT
to a "real" patch.

Guenter

---
v7: Set max_hw_timeout_ms
Rebased to v4.5-rc1
v6: Rename WDOG_RUNNING to WDOG_HW_RUNNING
Rebased to v4.4-rc2
v5: Rebased to v4.4-rc1
v4: No changes
v3: No changes
v2: No changes
---
drivers/watchdog/imx2_wdt.c | 74 ++++++++-------------------------------------
1 file changed, 13 insertions(+), 61 deletions(-)

diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
index e47966aa2db0..1a48cb28718f 100644
--- a/drivers/watchdog/imx2_wdt.c
+++ b/drivers/watchdog/imx2_wdt.c
@@ -25,14 +25,12 @@
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
-#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
-#include <linux/timer.h>
#include <linux/watchdog.h>

#define DRIVER_NAME "imx2-wdt"
@@ -60,7 +58,6 @@
struct imx2_wdt_device {
struct clk *clk;
struct regmap *regmap;
- struct timer_list timer; /* Pings the watchdog when closed */
struct watchdog_device wdog;
};

@@ -146,16 +143,6 @@ static int imx2_wdt_ping(struct watchdog_device *wdog)
return 0;
}

-static void imx2_wdt_timer_ping(unsigned long arg)
-{
- struct watchdog_device *wdog = (struct watchdog_device *)arg;
- struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
-
- /* ping it every wdog->timeout / 2 seconds to prevent reboot */
- imx2_wdt_ping(wdog);
- mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2);
-}
-
static int imx2_wdt_set_timeout(struct watchdog_device *wdog,
unsigned int new_timeout)
{
@@ -172,40 +159,19 @@ static int imx2_wdt_start(struct watchdog_device *wdog)
{
struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);

- if (imx2_wdt_is_running(wdev)) {
- /* delete the timer that pings the watchdog after close */
- del_timer_sync(&wdev->timer);
+ if (imx2_wdt_is_running(wdev))
imx2_wdt_set_timeout(wdog, wdog->timeout);
- } else
+ else
imx2_wdt_setup(wdog);

- return imx2_wdt_ping(wdog);
-}
-
-static int imx2_wdt_stop(struct watchdog_device *wdog)
-{
- /*
- * We don't need a clk_disable, it cannot be disabled once started.
- * We use a timer to ping the watchdog while /dev/watchdog is closed
- */
- imx2_wdt_timer_ping((unsigned long)wdog);
- return 0;
-}
-
-static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
-{
- struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+ set_bit(WDOG_HW_RUNNING, &wdog->status);

- if (imx2_wdt_is_running(wdev)) {
- imx2_wdt_set_timeout(wdog, wdog->timeout);
- imx2_wdt_timer_ping((unsigned long)wdog);
- }
+ return imx2_wdt_ping(wdog);
}

static const struct watchdog_ops imx2_wdt_ops = {
.owner = THIS_MODULE,
.start = imx2_wdt_start,
- .stop = imx2_wdt_stop,
.ping = imx2_wdt_ping,
.set_timeout = imx2_wdt_set_timeout,
.restart = imx2_wdt_restart,
@@ -253,7 +219,7 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
wdog->info = &imx2_wdt_info;
wdog->ops = &imx2_wdt_ops;
wdog->min_timeout = 1;
- wdog->max_timeout = IMX2_WDT_MAX_TIME;
+ wdog->max_hw_timeout_ms = IMX2_WDT_MAX_TIME * 1000;
wdog->parent = &pdev->dev;

ret = clk_prepare_enable(wdev->clk);
@@ -274,9 +240,10 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
watchdog_set_restart_priority(wdog, 128);
watchdog_init_timeout(wdog, timeout, &pdev->dev);

- setup_timer(&wdev->timer, imx2_wdt_timer_ping, (unsigned long)wdog);
-
- imx2_wdt_ping_if_active(wdog);
+ if (imx2_wdt_is_running(wdev)) {
+ imx2_wdt_set_timeout(wdog, wdog->timeout);
+ set_bit(WDOG_HW_RUNNING, &wdog->status);
+ }

/*
* Disable the watchdog power down counter at boot. Otherwise the power
@@ -309,7 +276,6 @@ static int __exit imx2_wdt_remove(struct platform_device *pdev)
watchdog_unregister_device(wdog);

if (imx2_wdt_is_running(wdev)) {
- del_timer_sync(&wdev->timer);
imx2_wdt_ping(wdog);
dev_crit(&pdev->dev, "Device removed: Expect reboot!\n");
}
@@ -323,10 +289,9 @@ static void imx2_wdt_shutdown(struct platform_device *pdev)

if (imx2_wdt_is_running(wdev)) {
/*
- * We are running, we need to delete the timer but will
- * give max timeout before reboot will take place
+ * We are running, configure max timeout before reboot
+ * will take place.
*/
- del_timer_sync(&wdev->timer);
imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
imx2_wdt_ping(wdog);
dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n");
@@ -344,10 +309,6 @@ static int imx2_wdt_suspend(struct device *dev)
if (imx2_wdt_is_running(wdev)) {
imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
imx2_wdt_ping(wdog);
-
- /* The watchdog is not active */
- if (!watchdog_active(wdog))
- del_timer_sync(&wdev->timer);
}

clk_disable_unprepare(wdev->clk);
@@ -373,19 +334,10 @@ static int imx2_wdt_resume(struct device *dev)
* watchdog again.
*/
imx2_wdt_setup(wdog);
+ }
+ if (imx2_wdt_is_running(wdev)) {
imx2_wdt_set_timeout(wdog, wdog->timeout);
imx2_wdt_ping(wdog);
- } else if (imx2_wdt_is_running(wdev)) {
- /* Resuming from non-deep sleep state. */
- imx2_wdt_set_timeout(wdog, wdog->timeout);
- imx2_wdt_ping(wdog);
- /*
- * But the watchdog is not active, then start
- * the timer again.
- */
- if (!watchdog_active(wdog))
- mod_timer(&wdev->timer,
- jiffies + wdog->timeout * HZ / 2);
}

return 0;