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authorWolfram Sang <wsa+renesas@sang-engineering.com>2020-12-19 20:34:15 +0300
committerWim Van Sebroeck <wim@linux-watchdog.org>2021-02-07 16:41:19 +0300
commitfa01fa70039cd969acde606672e2b9846205bd0f (patch)
treef8f2cc5c66df50150d2a6ae8381959d9d160fba0 /drivers/watchdog
parent17f0d1b9bd3333228b5c420f2dae2d7a980636b8 (diff)
downloadlinux-fa01fa70039cd969acde606672e2b9846205bd0f.tar.xz
watchdog: renesas_wdt: don't sleep in atomic context
In the restart handler, we hit multiple OOPSes. One because of usleep_range() and one because of RPM. So, instead of re-using rwdt_start(), we implement an atomic version of it in the restart handler. As a little bonus, reboot will occur sooner because we can now use the smallest divider in the custom restart routine. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Link: https://lore.kernel.org/r/20201219173415.21848-1-wsa+renesas@sang-engineering.com Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Diffstat (limited to 'drivers/watchdog')
-rw-r--r--drivers/watchdog/renesas_wdt.c30
1 files changed, 24 insertions, 6 deletions
diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index 47fce4de0110..d2b5074bca65 100644
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -9,6 +9,7 @@
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
@@ -50,6 +51,7 @@ struct rwdt_priv {
struct watchdog_device wdev;
unsigned long clk_rate;
u8 cks;
+ struct clk *clk;
};
static void rwdt_write(struct rwdt_priv *priv, u32 val, unsigned int reg)
@@ -125,13 +127,30 @@ static unsigned int rwdt_get_timeleft(struct watchdog_device *wdev)
return DIV_BY_CLKS_PER_SEC(priv, 65536 - val);
}
+/* needs to be atomic - no RPM, no usleep_range, no scheduling! */
static int rwdt_restart(struct watchdog_device *wdev, unsigned long action,
void *data)
{
struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
+ u8 val;
+
+ clk_prepare_enable(priv->clk);
+
+ /* Stop the timer before we modify any register */
+ val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME;
+ rwdt_write(priv, val, RWTCSRA);
+ /* Delay 2 cycles before setting watchdog counter */
+ udelay(DIV_ROUND_UP(2 * 1000000, priv->clk_rate));
- rwdt_start(wdev);
rwdt_write(priv, 0xffff, RWTCNT);
+ /* smallest divider to reboot soon */
+ rwdt_write(priv, 0, RWTCSRA);
+
+ readb_poll_timeout_atomic(priv->base + RWTCSRA, val,
+ !(val & RWTCSRA_WRFLG), 1, 100);
+
+ rwdt_write(priv, RWTCSRA_TME, RWTCSRA);
+
return 0;
}
@@ -191,7 +210,6 @@ static int rwdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct rwdt_priv *priv;
- struct clk *clk;
unsigned long clks_per_sec;
int ret, i;
u8 csra;
@@ -207,13 +225,13 @@ static int rwdt_probe(struct platform_device *pdev)
if (IS_ERR(priv->base))
return PTR_ERR(priv->base);
- clk = devm_clk_get(dev, NULL);
- if (IS_ERR(clk))
- return PTR_ERR(clk);
+ priv->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(priv->clk))
+ return PTR_ERR(priv->clk);
pm_runtime_enable(dev);
pm_runtime_get_sync(dev);
- priv->clk_rate = clk_get_rate(clk);
+ priv->clk_rate = clk_get_rate(priv->clk);
csra = readb_relaxed(priv->base + RWTCSRA);
priv->wdev.bootstatus = csra & RWTCSRA_WOVF ? WDIOF_CARDRESET : 0;
pm_runtime_put(dev);