linux-kernel - [PATCH v3 4/4] Watchdog: sp5100

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Date:   Tue, 18 Jan 2022 14:22:34 -0600
From:   Terry Bowman <terry.bowman@....com>
To:     <terry.bowman@....com>, <linux@...ck-us.net>,
        <linux-watchdog@...r.kernel.org>, <jdelvare@...e.com>,
        <linux-i2c@...r.kernel.org>, <wsa@...nel.org>,
        <andy.shevchenko@...il.com>, <rafael.j.wysocki@...el.com>
CC:     <linux-kernel@...r.kernel.org>, <wim@...ux-watchdog.org>,
        <rrichter@....com>, <thomas.lendacky@....com>,
        <Nehal-bakulchandra.Shah@....com>, <Basavaraj.Natikar@....com>,
        <Shyam-sundar.S-k@....com>, <Mario.Limonciello@....com>
Subject: [PATCH v3 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 family 17h family check and add a check for SMBus PCI
revision ID 0x51 or greater. The MMIO access method has been available
since at least SMBus controllers using PCI revision 0x51. This revision
check will support family 17h 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: Guenter Roeck <linux@...ck-us.net>
To: linux-watchdog@...r.kernel.org
To: Jean Delvare <jdelvare@...e.com>
To: linux-i2c@...r.kernel.org
To: Wolfram Sang <wsa@...nel.org>
To: Andy Shevchenko <andy.shevchenko@...il.com>
To: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Cc: linux-kernel@...r.kernel.org
Cc: Wim Van Sebroeck <wim@...ux-watchdog.org>
Cc: Robert Richter <rrichter@....com>
Cc: Thomas Lendacky <thomas.lendacky@....com>
---
 drivers/watchdog/sp5100_tco.c | 16 ++++------------
 drivers/watchdog/sp5100_tco.h |  1 +
 2 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index 36519a992ca1..b949dcd9f780 100644
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -86,6 +86,10 @@ 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) ||
@@ -461,18 +465,6 @@ 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 2df8f8b2c55b..4fac39a2f12f 100644
--- a/drivers/watchdog/sp5100_tco.h
+++ b/drivers/watchdog/sp5100_tco.h
@@ -88,3 +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           0x51
-- 
2.30.2