@@ -95,9 +95,12 @@ static int apple_wdt_ping(struct watchdog_device *wdd)
static int apple_wdt_set_timeout(struct watchdog_device *wdd, unsigned int s)
{
struct apple_wdt *wdt = to_apple_wdt(wdd);
+ u32 actual;
writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME);
- writel_relaxed(wdt->clk_rate * s, wdt->regs + APPLE_WDT_WD1_BITE_TIME);
+
+ actual = min(s, wdd->max_hw_heartbeat_ms / 1000);
+ writel_relaxed(wdt->clk_rate * actual, wdt->regs + APPLE_WDT_WD1_BITE_TIME);
wdd->timeout = s;
@@ -177,7 +180,7 @@ static int apple_wdt_probe(struct platform_device *pdev)
wdt->wdd.ops = &apple_wdt_ops;
wdt->wdd.info = &apple_wdt_info;
- wdt->wdd.max_timeout = U32_MAX / wdt->clk_rate;
+ wdt->wdd.max_hw_heartbeat_ms = U32_MAX / wdt->clk_rate * 1000;
wdt->wdd.timeout = APPLE_WDT_TIMEOUT_DEFAULT;
wdt_ctrl = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CTRL);
The hardware only supports timeouts slightly below 3mins, but by using max_hw_heartbeat_ms we can let the kernel take care of supporting larger timeouts than that requested from userspace. Switching to max_hw_heartbeat_ms also means our set_timeout function now needs to configure the hardware to the minimum of either the requested timeout (in seconds) or the maximum supported by the user (in seconds). Signed-off-by: Florian Klink <flokli@flokli.de> --- Changes in v2: - Use the minimum of wdd->max_hw_heartbeat_ms / 1000 and userspace-requested timeout as documented in watchdog-kernel-api.rst - Link to v1: https://lore.kernel.org/asahi/20250506120111.5041-1-flokli@flokli.de/ --- drivers/watchdog/apple_wdt.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)