xHCI: Correct the #define XHCI_LEGACY_DISABLE_SMI

commit 95018a53 upstream.

Re-define XHCI_LEGACY_DISABLE_SMI and used it in right way. All SMI enable
bits will be cleared to zero and flag bits 29:31 are also cleared to zero.
Other bits should be presvered as Table 146.

This patch should be backported to kernels as old as 2.6.31.
Signed-off-by: Alex He <alex.he@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

drivers/usb/host/pci-quirks.c

@@ -458,9 +458,13 @@ static void __devinit quirk_usb_handoff_xhci(struct pci_dev *pdev)
 		}
 	}
 
-	/* Disable any BIOS SMIs */
-	writel(XHCI_LEGACY_DISABLE_SMI,
-			base + ext_cap_offset + XHCI_LEGACY_CONTROL_OFFSET);
+	val = readl(base + ext_cap_offset + XHCI_LEGACY_CONTROL_OFFSET);
+	/* Mask off (turn off) any enabled SMIs */
+	val &= XHCI_LEGACY_DISABLE_SMI;
+	/* Mask all SMI events bits, RW1C */
+	val |= XHCI_LEGACY_SMI_EVENTS;
+	/* Disable any BIOS SMIs and clear all SMI events*/
+	writel(val, base + ext_cap_offset + XHCI_LEGACY_CONTROL_OFFSET);
 
 hc_init:
 	op_reg_base = base + XHCI_HC_LENGTH(readl(base));

drivers/usb/host/xhci-ext-caps.h

@@ -62,8 +62,9 @@
 /* USB Legacy Support Control and Status Register  - section 7.1.2 */
 /* Add this offset, plus the value of xECP in HCCPARAMS to the base address */
 #define XHCI_LEGACY_CONTROL_OFFSET	(0x04)
-/* bits 1:2, 5:12, and 17:19 need to be preserved; bits 21:28 should be zero */
-#define	XHCI_LEGACY_DISABLE_SMI		((0x3 << 1) + (0xff << 5) + (0x7 << 17))
+/* bits 1:3, 5:12, and 17:19 need to be preserved; bits 21:28 should be zero */
+#define	XHCI_LEGACY_DISABLE_SMI		((0x7 << 1) + (0xff << 5) + (0x7 << 17))
+#define XHCI_LEGACY_SMI_EVENTS		(0x7 << 29)
 
 /* command register values to disable interrupts and halt the HC */
 /* start/stop HC execution - do not write unless HC is halted*/