linux-kernel - [PATCH v2 4/4] Watchdog: sp5100

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Date:   Wed, 3 Nov 2021 11:15:21 -0500
From:   Terry Bowman <terry.bowman@....com>
To:     <linux-watchdog@...r.kernel.org>
CC:     <terry.bowman@....com>, <rrichter@....com>,
        <linux-kernel@...r.kernel.org>, <wim@...ux-watchdog.org>,
        <linux@...ck-us.net>, <ssg.sos.patches@....com>,
        <sudheesh.mavila@....com>
Subject: [PATCH v2 4/4] Watchdog: sp5100_tco: Enable Family 17h+ CPUs

The driver currently uses a CPU family match of 17h to determine
EFCH_PM_DECODEEN_WDT_TMREN register support. This family check will not
support future AMD CPUs and instead will require driver updates to add
support.

Remove the Fam17h family check and add a check for SMBus PCI revision ID
0x59. This will support Fam17h and future AMD processors including EFCH
functionality without requiring driver changes.

Co-developed-by: Robert Richter <rrichter@....com>
Signed-off-by: Robert Richter <rrichter@....com>
Signed-off-by: Terry Bowman <terry.bowman@....com>
To: linux-watchdog@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Cc: Wim Van Sebroeck <wim@...ux-watchdog.org>
Cc: Guenter Roeck <linux@...ck-us.net>
Cc: Robert Richter <rrichter@....com>
---
 drivers/watchdog/sp5100_tco.c | 16 ++++------------
 drivers/watchdog/sp5100_tco.h |  2 +-
 2 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index 4777e672a8ad..8930b94aae47 100644
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -87,6 +87,10 @@ 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 &&
+	    sp5100_tco_pci->device == PCI_DEVICE_ID_AMD_KERNCZ_SMBUS &&
+	    sp5100_tco_pci->revision >= AMD_ZEN_SMBUS_PCI_REV) {
+		return efch_mmio;
 	} else if (dev->vendor == PCI_VENDOR_ID_AMD &&
 	    ((dev->device == PCI_DEVICE_ID_AMD_HUDSON2_SMBUS &&
 	     dev->revision >= 0x41) ||
@@ -472,18 +476,6 @@ static int sp5100_tco_setupdevice(struct device *dev,
 		break;
 	case efch:
 		dev_name = SB800_DEVNAME;
-		/*
-		 * On Family 17h devices, the EFCH_PM_DECODEEN_WDT_TMREN bit of
-		 * EFCH_PM_DECODEEN not only enables the EFCH_PM_WDT_ADDR memory
-		 * region, it also enables the watchdog itself.
-		 */
-		if (boot_cpu_data.x86 == 0x17) {
-			val = sp5100_tco_read_pm_reg8(EFCH_PM_DECODEEN);
-			if (!(val & EFCH_PM_DECODEEN_WDT_TMREN)) {
-				sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN, 0xff,
-							  EFCH_PM_DECODEEN_WDT_TMREN);
-			}
-		}
 		val = sp5100_tco_read_pm_reg8(EFCH_PM_DECODEEN);
 		if (val & EFCH_PM_DECODEEN_WDT_TMREN)
 			mmio_addr = EFCH_PM_WDT_ADDR;
diff --git a/drivers/watchdog/sp5100_tco.h b/drivers/watchdog/sp5100_tco.h
index 73f179a1d6e5..3a37bffc96b4 100644
--- a/drivers/watchdog/sp5100_tco.h
+++ b/drivers/watchdog/sp5100_tco.h
@@ -88,4 +88,4 @@
 #define EFCH_PM_ACPI_MMIO_PM_ADDR	(EFCH_PM_ACPI_MMIO_ADDR +	\
 					 EFCH_PM_ACPI_MMIO_PM_OFFSET)
 #define EFCH_PM_ACPI_MMIO_PM_SIZE       8
-
+#define AMD_ZEN_SMBUS_PCI_REV           0x59
-- 
2.25.1