watchdog: sp5100_tco: Immediately trigger upon starting.

commit 4eda19cc8a29cde3580ed73bf11dc73b4e757697 upstream.

The watchdog countdown is supposed to begin when the device file is
opened. Instead, it would begin countdown upon the first write to or
close of the device file. Now, the ping operation is called within the
start operation which ensures the countdown begins. From experimenation,
it does not appear possible to do this with a single write including
both the start bit and the trigger bit. So, it is done as two distinct
writes.

Signed-off-by: Gregory Oakes <gregory.oakes@amd.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230316201312.17538-1-gregory.oakes@amd.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index a730ecbf78cd5d53d3f08bdc919f3abcdec7df88..0db77c90b4b662cd4ec304654ed652dc7f1e598a 100644 (file)
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -104,6 +104,10 @@ static int tco_timer_start(struct watchdog_device *wdd)
        val |= SP5100_WDT_START_STOP_BIT;
        writel(val, SP5100_WDT_CONTROL(tco->tcobase));
 
+       /* This must be a distinct write. */
+       val |= SP5100_WDT_TRIGGER_BIT;
+       writel(val, SP5100_WDT_CONTROL(tco->tcobase));
+
        return 0;
 }