On 24.06.25 08:19, Gopinath Sekar wrote:
Added a check to ensure the requested timeout does not exceed the
hardware's maximum supported value. This prevents register overflow
and ensures watchdog reliability.
So, added a check in qcom_wdt_start() to ensure the requested timeout
does not exceed the hardware-supported maximum value.
The timeout is first converted to watchdog ticks and then compared
against QCOM_WDT_MAX_TIMEOUT. This helps prevent misconfiguration
and potential watchdog misbehavior due to overflow.
QCOM_WDT_MAX_TIMEOUT is set to 0xFFFFF, as Qualcomm SoCs typically
use 20 bits to store bark/bite timeout values.
This work builds upon the previous submission:
https://lore.kernel.org/u-boot/[email protected]/
Signed-off-by: Gopinath Sekar <[email protected]>
---
drivers/watchdog/qcom-wdt.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
index adbb5aacdc3..eeeea4c24b7 100644
--- a/drivers/watchdog/qcom-wdt.c
+++ b/drivers/watchdog/qcom-wdt.c
@@ -17,6 +17,9 @@
#include <asm/io.h>
+/* Maximum allowed timeout value in Qcom SoCs*/
+#define QCOM_WDT_MAX_TIMEOUT 0xfffff
+
enum wdt_reg {
WDT_RST,
WDT_EN,
@@ -55,8 +58,20 @@ static void __iomem *wdt_addr(struct qcom_wdt *wdt, enum
wdt_reg reg)
int qcom_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
{
struct qcom_wdt *wdt = dev_get_priv(dev);
- ulong bark_timeout_s = ((timeout_ms - 1) * wdt->clk_rate) / 1000;
- ulong bite_timeout_s = (timeout_ms * wdt->clk_rate) / 1000;
+ u64 tmp_timeout;
+ u32 bark_timeout_s, bite_timeout_s;
+
+ /* Compute timeout in watchdog ticks */
+ tmp_timeout = (timeout_ms * (u64)wdt->clk_rate) / 1000;
+ if (tmp_timeout > QCOM_WDT_MAX_TIMEOUT) {
+ dev_err(dev, "Requested timeout (%llu ms) exceeds maximum allowed
value (%llu ms).\n",
+ timeout_ms, ((u64)QCOM_WDT_MAX_TIMEOUT * 1000) /
wdt->clk_rate);
+ return -EINVAL;
Not sure, but wouldn't it be better to use this max timeout value in
this case instead of returning with error? Best with a changed dev_err
or dev_warn explaining this changed behavior.
Thanks,
Stefan
