linux-kernel - [PATCH v4 9/9] i2c: piix4: Enable EFCH MMIO for Family 17h+

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Message-ID: <20220130184130.176646-10-terry.bowman@amd.com>
Date:   Sun, 30 Jan 2022 12:41:30 -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>,
        <sudheesh.mavila@....com>, <Nehal-bakulchandra.Shah@....com>,
        <Basavaraj.Natikar@....com>, <Shyam-sundar.S-k@....com>,
        <Mario.Limonciello@....com>
Subject: [PATCH v4 9/9] i2c: piix4: Enable EFCH MMIO for Family 17h+

Enable EFCH MMIO using check for SMBus PCI revision ID value 0x51 or
greater. SMBus PCI revision ID 0x51 is first used by family 17h. This
PCI revision ID check will also enable future AMD processors with the
same EFCH SMBus controller HW.

Signed-off-by: Terry Bowman <terry.bowman@....com>
---
 drivers/i2c/busses/i2c-piix4.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index c5325cadaf55..6a9495d994bc 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -101,6 +101,8 @@
 #define SB800_PIIX4_FCH_PM_ADDR			0xFED80300
 #define SB800_PIIX4_FCH_PM_SIZE			8
 
+#define AMD_PCI_SMBUS_REVISION_MMIO		0x51
+
 /* insmod parameters */
 
 /* If force is set to anything different from 0, we forcibly enable the
@@ -229,6 +231,13 @@ static void piix4_sb800_region_release(struct device *dev,
 	release_region(SB800_PIIX4_SMB_IDX, SB800_PIIX4_SMB_MAP_SIZE);
 }
 
+static bool piix4_sb800_use_mmio(struct pci_dev *PIIX4_dev)
+{
+	return (PIIX4_dev->vendor == PCI_VENDOR_ID_AMD &&
+		PIIX4_dev->device == PCI_DEVICE_ID_AMD_KERNCZ_SMBUS &&
+		PIIX4_dev->revision >= AMD_PCI_SMBUS_REVISION_MMIO);
+}
+
 static int piix4_setup(struct pci_dev *PIIX4_dev,
 		       const struct pci_device_id *id)
 {
@@ -339,7 +348,7 @@ static int piix4_setup_sb800_smba(struct pci_dev *PIIX4_dev,
 	u8 smba_en_hi;
 	int retval;
 
-	mmio_cfg.use_mmio = 0;
+	mmio_cfg.use_mmio = piix4_sb800_use_mmio(PIIX4_dev);
 	retval = piix4_sb800_region_request(&PIIX4_dev->dev, &mmio_cfg);
 	if (retval)
 		return retval;
@@ -943,7 +952,7 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
 		return -ENOMEM;
 	}
 
-	adapdata->mmio_cfg.use_mmio = 0;
+	adapdata->mmio_cfg.use_mmio = piix4_sb800_use_mmio(dev);
 	adapdata->smba = smba;
 	adapdata->sb800_main = sb800_main;
 	adapdata->port = port << piix4_port_shift_sb800;
-- 
2.30.2