From: Bhavana Nagendra <bnagendr@redhat.com>
Subject: [RHEL5 patch] : RHEL5B2 does not support legacy IDE mode of SB600  SATA
Date: Mon, 15 Jan 2007 12:02:06 -0500
Bugzilla: 221636
Message-Id: <45ABB38E.8080200@redhat.com>
Changelog: sata: support legacy IDE mode of SB600 SATA


This is a patch from AMD-GPG that fixes the RHEL5 codebase and allows it 
to support legacy.
IDE mode of SB600 SATA.   AMD/ATI SB600 SATA controller supports 4 modes:
  legacy IDE, native IDE, AHCI, RAID

The ahci driver in RHEL5 (beta 2) tries to claim all 4 modes of SB600 
SATA, but fails in
legacy IDE mode.


--- linux-2.6.18.x86_64/drivers/pci/quirks.c.orig	2007-01-15 11:45:42.000000000 -0500
+++ linux-2.6.18.x86_64/drivers/pci/quirks.c	2007-01-15 11:47:22.000000000 -0500
@@ -1230,6 +1230,27 @@ static void __devinit quirk_jmicron_dual
 
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_JMICRON, PCI_ANY_ID, quirk_jmicron_dualfn);
 
+
+/*
+ *  Some BIOS set AMD/ATI SB600 SATA as IDE mode for backward compatibility, 
+ *  but Linux should set it back to AHCI mode since ahci is supported now.
+ */
+static void __devinit quirk_sb600_sata(struct pci_dev *pdev)
+{
+	if ((pdev->class >> 8) == PCI_CLASS_STORAGE_IDE) {
+		u8 tmp;
+
+		pci_read_config_byte(pdev, 0x40, &tmp);
+		pci_write_config_byte(pdev, 0x40, tmp|1);
+		pci_write_config_byte(pdev, PCI_CLASS_PROG, 1);
+		pci_write_config_byte(pdev, PCI_CLASS_DEVICE, 6);
+		pci_write_config_byte(pdev, 0x40, tmp);
+
+		pdev->class = 0x010601;
+	}
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_IXP600_SATA, quirk_sb600_sata);
+
 #endif
 
 #ifdef CONFIG_X86_IO_APIC