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 4afc468d8ed12fdd0cc473aeea661c64ac333d65..1e327fb1ad202d60ff0272432820226ef4fc412a 100644 (file)
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -108,6 +108,10 @@ 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;
 }