[PATCH 1/2] watchdog: dw_wdt: do not register restart handler

[PATCH 1/2] watchdog: dw_wdt: do not register restart handler

[Sascha Hauer]

The designware watchdog driver doesn't have a special reset function,
instead it only uses the regular watchdog to reset the SoC. Since
0ed7bb09f2ef7b ("watchdog: add option to provide fall-back restart handler")
the watchdog core provides the same functionality, so just drop the
restart functionality from the driver.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/watchdog/dw_wdt.c | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 178e0a29f1..398bbfe05f 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -16,7 +16,6 @@
 #include <init.h>
 #include <io.h>
 #include <of.h>
-#include <restart.h>
 #include <watchdog.h>
 #include <linux/clk.h>
 #include <linux/err.h>
@@ -37,7 +36,6 @@
 
 struct dw_wdt {
 	void __iomem		*regs;
-	struct restart_handler	restart;
 	struct watchdog		wdd;
 	struct reset_control	*rst;
 	unsigned int		rate;
@@ -115,19 +113,6 @@ static int dw_wdt_set_timeout(struct watchdog *wdd, unsigned int top_s)
 	return 0;
 }
 
-static void __noreturn dw_wdt_restart_handle(struct restart_handler *rst)
-{
-	struct dw_wdt *dw_wdt;
-
-	dw_wdt = container_of(rst, struct dw_wdt, restart);
-
-	dw_wdt->wdd.set_timeout(&dw_wdt->wdd, -1);
-
-	mdelay(1000);
-
-	hang();
-}
-
 static int dw_wdt_drv_probe(struct device *dev)
 {
 	struct watchdog *wdd;
@@ -173,13 +158,6 @@ static int dw_wdt_drv_probe(struct device *dev)
 	if (ret)
 		goto out_disable_clk;
 
-	dw_wdt->restart.name = "dw_wdt";
-	dw_wdt->restart.restart = dw_wdt_restart_handle;
-
-	ret = restart_handler_register(&dw_wdt->restart);
-	if (ret)
-		dev_warn(dev, "cannot register restart handler\n");
-
 	if (dw_wdt->rst)
 		reset_control_deassert(dw_wdt->rst);
 	else
-- 
2.39.2

[PATCH 2/2] watchdog: fix watchdog restart handler when autoping is enabled

[Sascha Hauer]

When the watchdog autoping feature is enabled it will ping the watchdog
every 0.5s. This becomes a problem when the fallback restart handler is
called to reset the CPU. It will then set the watchdog to trigger in one
second and waits for CPU reset using mdelay(). During the mdelay() the
autoping poller will continue to feed the watchdog, so we never actually
reset the CPU.

Use mdelay_non_interruptible() instead so that no poller can run in the
background.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/watchdog/wd_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/wd_core.c b/drivers/watchdog/wd_core.c
index f39a8f4522..42cbd7b72c 100644
--- a/drivers/watchdog/wd_core.c
+++ b/drivers/watchdog/wd_core.c
@@ -178,7 +178,8 @@ static void __noreturn watchdog_restart_handle(struct restart_handler *this)
 		ret = watchdog_set_timeout(wd, 1);
 
 	BUG_ON(ret);
-	mdelay(2000);
+
+	mdelay_non_interruptible(2000);
 
 	pr_emerg("Watchdog failed to reset the machine\n");
 	hang();
-- 
2.39.2

Re: [PATCH 1/2] watchdog: dw_wdt: do not register restart handler

[Sascha Hauer]

On Mon, 27 May 2024 11:50:56 +0200, Sascha Hauer wrote:
> The designware watchdog driver doesn't have a special reset function,
> instead it only uses the regular watchdog to reset the SoC. Since
> 0ed7bb09f2ef7b ("watchdog: add option to provide fall-back restart handler")
> the watchdog core provides the same functionality, so just drop the
> restart functionality from the driver.
> 
> 
> [...]

Applied, thanks!

[1/2] watchdog: dw_wdt: do not register restart handler
      https://git.pengutronix.de/cgit/barebox/commit/?id=421ac5c9ec21 (link may not be stable)
[2/2] watchdog: fix watchdog restart handler when autoping is enabled
      https://git.pengutronix.de/cgit/barebox/commit/?id=77a000225df4 (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>