On 2/17/25 19:16, Heyi Guo wrote:
Aspeed watchdog uses counting down logic, so the value set to register
should be the value of subtracting pretimeout from total timeout.
Fixes: 9ec0b7e06835 ("watchdog: aspeed: Enable pre-timeout interrupt")
Signed-off-by: Heyi Guo <guoheyi@xxxxxxxxxxxxxxxxx>
Cc: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Joel Stanley <joel@xxxxxxxxx>
Cc: Andrew Jeffery <andrew@xxxxxxxxxxxxxxxxxxxx>
Cc: Eddie James <eajames@xxxxxxxxxxxxx>
---
drivers/watchdog/aspeed_wdt.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index b4773a6aaf8c..520d8aba12a5 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -187,6 +187,13 @@ static int aspeed_wdt_set_pretimeout(struct watchdog_device *wdd,
u32 actual = pretimeout * WDT_RATE_1MHZ;
u32 s = wdt->cfg->irq_shift;
u32 m = wdt->cfg->irq_mask;
+ u32 reload = readl(wdt->base + WDT_RELOAD_VALUE);
+
It is unusual to use a register value here and not the configured timeout
value. I would have assumed that pretimeout is compared against wdt->timout,
not against the register value, and that the multiplication with WDT_RATE_1MHZ
is done after validation. This needs an explanation.
+ if (actual >= reload)
+ return -EINVAL;
+
On top of that, you'll also need to explain why watchdog_pretimeout_invalid()
and with it the validation in watchdog_set_pretimeout() does not work for this
watchdog and why this extra validation is necessary.
Guenter
+ /* watchdog timer is counting down */
+ actual = reload - actual;
wdd->pretimeout = pretimeout;
wdt->ctrl &= ~m;
