On 10/8/21 12:52 AM, Jan Kiszka wrote:
On 08.10.21 02:33, Guenter Roeck wrote:
This reverts commit cb011044e34c ("watchdog: iTCO_wdt: Account for
rebooting on second timeout") and commit aec42642d91f ("watchdog: iTCO_wdt:
Fix detection of SMI-off case") since those patches cause a regression
on certain boards (https://bugzilla.kernel.org/show_bug.cgi?id=213809).
While this revert may result in some boards to only reset after twice
the configured timeout value, that is still better than a watchdog reset
after half the configured value.
Fixes: cb011044e34c ("watchdog: iTCO_wdt: Account for rebooting on second timeout")
Fixes: aec42642d91f ("watchdog: iTCO_wdt: Fix detection of SMI-off case")
Cc: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Cc: Mantas Mikulėnas <grawity@xxxxxxxxx>
Reported-by: Javier S. Pedro <debbugs@xxxxxxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
drivers/watchdog/iTCO_wdt.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index 643c6c2d0b72..ced2fc0deb8c 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -71,8 +71,6 @@
#define TCOBASE(p) ((p)->tco_res->start)
/* SMI Control and Enable Register */
#define SMI_EN(p) ((p)->smi_res->start)
-#define TCO_EN (1 << 13)
-#define GBL_SMI_EN (1 << 0)
#define TCO_RLD(p) (TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */
#define TCOv1_TMR(p) (TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/
@@ -357,12 +355,8 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
tmrval = seconds_to_ticks(p, t);
- /*
- * If TCO SMIs are off, the timer counts down twice before rebooting.
- * Otherwise, the BIOS generally reboots when the SMI triggers.
- */
- if (p->smi_res &&
- (inl(SMI_EN(p)) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN))
+ /* For TCO v1 the timer counts down twice before rebooting */
+ if (p->iTCO_version == 1)
tmrval /= 2;
/* from the specs: */
@@ -527,7 +521,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
* Disables TCO logic generating an SMI#
*/
val32 = inl(SMI_EN(p));
- val32 &= ~TCO_EN; /* Turn off SMI clearing watchdog */
+ val32 &= 0xffffdfff; /* Turn off SMI clearing watchdog */
outl(val32, SMI_EN(p));
}
Sigh, how broken is this architecture of the iTCO? Agreed, this leaves
no option then.
BTW, the fact that we saw an inconsistency in read-back timeout
indicates that there is still an issue for the remaining /= 2 case
(means v1), but I'm loosing interest in fixing those issues, given how
hard it is to test broadly without breaking users first.
Agreed. This is because the /=2 handling is only implemented in
iTCO_wdt_set_timeout() without matching code in iTCO_wdt_get_timeleft().
I don't have hardware to test, so I am not going to touch that code
myself. We can address that if/when someone reports the actual problem
and has the ability to test a fix.
Thanks,
Guenter
