diff options
| author | Oleksandr Ocheretnyi <oocheret@cisco.com> | 2024-09-13 12:14:03 -0700 |
|---|---|---|
| committer | Wim Van Sebroeck <wim@linux-watchdog.org> | 2024-11-04 13:12:58 +0100 |
| commit | daa814d784ac034c62ab3fb0ef83daeafef527e2 (patch) | |
| tree | d7560cf209bd05058abc684a4b462193647ecefb /drivers/watchdog | |
| parent | 4497ee914f10264894b08066cbee026604cd244f (diff) | |
iTCO_wdt: mask NMI_NOW bit for update_no_reboot_bit() call
Commit da23b6faa8bf ("watchdog: iTCO: Add support for Cannon Lake
PCH iTCO") does not mask NMI_NOW bit during TCO1_CNT register's
value comparison for update_no_reboot_bit() call causing following
failure:
...
iTCO_vendor_support: vendor-support=0
iTCO_wdt iTCO_wdt: unable to reset NO_REBOOT flag, device
disabled by hardware/BIOS
...
and this can lead to unexpected NMIs later during regular
crashkernel's workflow because of watchdog probe call failures.
This change masks NMI_NOW bit for TCO1_CNT register values to
avoid unexpected NMI_NOW bit inversions.
Fixes: da23b6faa8bf ("watchdog: iTCO: Add support for Cannon Lake PCH iTCO")
Signed-off-by: Oleksandr Ocheretnyi <oocheret@cisco.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20240913191403.2560805-1-oocheret@cisco.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Diffstat (limited to 'drivers/watchdog')
| -rw-r--r-- | drivers/watchdog/iTCO_wdt.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c index 35b358bcf94c..f01ed38aba67 100644 --- a/drivers/watchdog/iTCO_wdt.c +++ b/drivers/watchdog/iTCO_wdt.c @@ -82,6 +82,13 @@ #define TCO2_CNT(p) (TCOBASE(p) + 0x0a) /* TCO2 Control Register */ #define TCOv2_TMR(p) (TCOBASE(p) + 0x12) /* TCOv2 Timer Initial Value*/ +/* + * NMI_NOW is bit 8 of TCO1_CNT register + * Read/Write + * This bit is implemented as RW but has no effect on HW. + */ +#define NMI_NOW BIT(8) + /* internal variables */ struct iTCO_wdt_private { struct watchdog_device wddev; @@ -219,13 +226,23 @@ static int update_no_reboot_bit_cnt(void *priv, bool set) struct iTCO_wdt_private *p = priv; u16 val, newval; - val = inw(TCO1_CNT(p)); + /* + * writing back 1b1 to NMI_NOW of TCO1_CNT register + * causes NMI_NOW bit inversion what consequently does + * not allow to perform the register's value comparison + * properly. + * + * NMI_NOW bit masking for TCO1_CNT register values + * helps to avoid possible NMI_NOW bit inversions on + * following write operation. + */ + val = inw(TCO1_CNT(p)) & ~NMI_NOW; if (set) val |= BIT(0); else val &= ~BIT(0); outw(val, TCO1_CNT(p)); - newval = inw(TCO1_CNT(p)); + newval = inw(TCO1_CNT(p)) & ~NMI_NOW; /* make sure the update is successful */ return val != newval ? -EIO : 0; |