[PATCH 1/1] watchdog: sp5100_tco: Use EFCH MMIO for newer Hygon FCH

[Yingjie Gao]

Commit 009637de1f65 ("watchdog: sp5100_tco: support Hygon FCH/SCH
(Server Controller Hub)") added Hygon vendor matching to the efch
layout selection, but newer Hygon 0x790b SMBus devices still need the
efch_mmio path.

The efch_mmio path enables EFCH_PM_DECODEEN_WDT_TMREN before probing the
watchdog MMIO block. If firmware leaves that bit clear and the driver
picks the legacy efch path instead, probe falls back to the alternate
window and fails with "Watchdog hardware is disabled".

Select efch_mmio for Hygon 0x790b devices with revision 0x51 or later,
matching the equivalent AMD behavior and allowing the watchdog to
initialize on those systems.

Fixes: 009637de1f65 ("watchdog: sp5100_tco: support Hygon FCH/SCH (Server Controller Hub)")
Signed-off-by: Yingjie Gao <gaoyingjie@xxxxxxxxxxxxx>
---
 drivers/watchdog/sp5100_tco.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index 2bd3dc25cb03..7e99c3b1f367 100644
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -92,7 +92,8 @@ static enum tco_reg_layout tco_reg_layout(struct pci_dev *dev)
 	    dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&
 	    dev->revision < 0x40) {
 		return sp5100;
-	} else if (dev->vendor == PCI_VENDOR_ID_AMD &&
+	} else if ((dev->vendor == PCI_VENDOR_ID_AMD ||
+		    dev->vendor == PCI_VENDOR_ID_HYGON) &&
 	    sp5100_tco_pci->device == PCI_DEVICE_ID_AMD_KERNCZ_SMBUS &&
 	    sp5100_tco_pci->revision >= AMD_ZEN_SMBUS_PCI_REV) {
 		return efch_mmio;
-- 
2.20.1