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 93bd302ae7c5d054063d339b090dd75cd692fbde..704d7c527fcb9ab4da7bec44d3fa26b010ac779a 100644 (file)
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -98,6 +98,10 @@ 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;
 }