x86_64: check and enable MMCONFIG for AMD Family 10h Opteron

Index: linux-2.6/arch/x86_64/kernel/setup.c
===================================================================
@@ -507,6 +507,32 @@
 }
 #endif
 
+/*[39:8] */
+/* why not using 0xfe000000 ? */
+#define FAM10H_PCI_MMIO_BASE 0xc0000000
+static void fam10h_check_enable_mmcfg(struct cpuinfo_x86 *c)
+{
+	u32 low, high, address;
+
+	address = 0xc0010058;
+	if (rdmsr_safe(address, &low, &high))
+		return;
+
+	if (low & 1)
+		return;
+
+	printk(KERN_INFO "Enable MMCONFIG on AMD Family 10h\n");
+	/*
+	 * if it is not enable, let enable it and assume only one segement
+	 * with 256 buses
+	 */
+	low &= ~(0xfff00000 | (0xf<<2));
+	low |= (8<<2) | (1<<0);
+	high &= ~(0x0000ffff);
+	high |= (FAM10H_PCI_MMIO_BASE>>(32-8));
+	wrmsr_safe(address, low, high);
+}
+
 /*
  * On a AMD dual core setup the lower bits of the APIC id distingush the cores.
  * Assumes number of cores is a power of two.

@@ -655,6 +681,9 @@
 	/* Family 10 doesn't support C states in MWAIT so don't use it */
 	if (c->x86 == 0x10 && !force_mwait)
 		clear_bit(X86_FEATURE_MWAIT, &c->x86_capability);
+
+	if (c->x86 == 0x10)
+		fam10h_check_enable_mmcfg(c);
 }
 
 static void __cpuinit detect_ht(struct cpuinfo_x86 *c)