From: Bhavna Sarathy <bnagendr@redhat.com>
Date: Wed, 25 Mar 2009 13:50:26 -0400
Subject: [i2c] add support for SB800 SMBus
Message-id: 20090325175025.13395.12932.sendpatchset@localhost.localdomain
O-Subject: [RHEL5.4 PATCH] Add support for SB800 SMBus
Bugzilla: 488746
RH-Acked-by: Brian Maly <bmaly@redhat.com>

Resolves BZ 488746

This patch adds support for the AMD SB800 family of products. Major changes
include the changes to addressing the SMBUS registers at different location,
from previous compatible parts from AMD such as SB400/SB600/SB700.   For
SB800, the main features and register definitions of SMBUS and other
interfaces are still compatible with the previous products with the
only change being in how to access the internal registers for these
blocks.

The patch has been accepted upstream and will appear in 2.6.30 kernel.
http://marc.info/?l=linux-i2c&m=123575347413022&w=2

Here is the final accepted patch:
ftp://ftp.kernel.org/pub/linux/kernel/people/jdelvare/linux-2.6/jdelvare-i2c/i2c-piix4-add-support-for-sb800.patch

The brew build has been successfully tested on SB800 internal reference
board.

Please review and ACK for RHEL5.4.

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index dfaab59..a0a5c2c 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -207,6 +207,67 @@ static int __devinit piix4_setup(struct pci_dev *PIIX4_dev,
 	return 0;
 }
 
+static int __devinit piix4_setup_sb800(struct pci_dev *PIIX4_dev,
+				const struct pci_device_id *id)
+{
+	unsigned short smba_idx = 0xcd6;
+	u8 smba_en_lo, smba_en_hi, i2ccfg, i2ccfg_offset = 0x10, smb_en = 0x2c;
+
+	/* SB800 SMBus does not support forcing address */
+	if (force || force_addr) {
+		dev_err(&PIIX4_dev->dev, "SB800 SMBus does not support "
+			"forcing address!\n");
+		return -EINVAL;
+	}
+
+	/* Determine the address of the SMBus areas */
+	if (!request_region(smba_idx, 2, "smba_idx")) {
+		dev_err(&PIIX4_dev->dev, "SMBus base address index region "
+			"0x%x already in use!\n", smba_idx);
+		return -EBUSY;
+	}
+	outb_p(smb_en, smba_idx);
+	smba_en_lo = inb_p(smba_idx + 1);
+	outb_p(smb_en + 1, smba_idx);
+	smba_en_hi = inb_p(smba_idx + 1);
+	release_region(smba_idx, 2);
+
+	if ((smba_en_lo & 1) == 0) {
+		dev_err(&PIIX4_dev->dev,
+			"Host SMBus controller not enabled!\n");
+		return -ENODEV;
+	}
+
+	piix4_smba = ((smba_en_hi << 8) | smba_en_lo) & 0xffe0;
+	if (!request_region(piix4_smba, SMBIOSIZE, piix4_driver.name)) {
+		dev_err(&PIIX4_dev->dev, "SMBus region 0x%x already in use!\n",
+			piix4_smba);
+		return -EBUSY;
+	}
+
+	/* Request the SMBus I2C bus config region */
+	if (!request_region(piix4_smba + i2ccfg_offset, 1, "i2ccfg")) {
+		dev_err(&PIIX4_dev->dev, "SMBus I2C bus config region "
+			"0x%x already in use!\n", piix4_smba + i2ccfg_offset);
+		release_region(piix4_smba, SMBIOSIZE);
+		piix4_smba = 0;
+		return -EBUSY;
+	}
+	i2ccfg = inb_p(piix4_smba + i2ccfg_offset);
+	release_region(piix4_smba + i2ccfg_offset, 1);
+
+	if (i2ccfg & 1)
+		dev_dbg(&PIIX4_dev->dev, "Using IRQ for SMBus.\n");
+	else
+		dev_dbg(&PIIX4_dev->dev, "Using SMI# for SMBus.\n");
+
+	dev_info(&PIIX4_dev->dev,
+		 "SMBus Host Controller at 0x%x, revision %d\n",
+		 piix4_smba, i2ccfg >> 4);
+
+	return 0;
+}
+
 /* Another internally used function */
 static int piix4_transaction(void)
 {
@@ -423,7 +484,14 @@ static int __devinit piix4_probe(struct pci_dev *dev,
 {
 	int retval;
 
-	retval = piix4_setup(dev, id);
+	if ((dev->vendor == PCI_VENDOR_ID_ATI) &&
+	    (dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS) &&
+	    (dev->revision >= 0x40))
+		/* base address location etc changed in SB800 */
+		retval = piix4_setup_sb800(dev, id);
+	else
+		retval = piix4_setup(dev, id);
+
 	if (retval)
 		return retval;