x86_64: check and enable MMCONFIG for AMD Family 10h

So we can use MMCONF when MMCONF is not set by BIOS

using TOP_MEM2 msr to get memory top, and try to scan fam10h mmio routing to
make sure the range is not conflicted with some prefetch MMIO that is above 4G.
(current only LinuxBIOS assign 64 bit mmio above 4G for some co-processor)

Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/setup_64.c

@@ -29,6 +29,7 @@
 #include <linux/crash_dump.h>
 #include <linux/root_dev.h>
 #include <linux/pci.h>
+#include <asm/pci-direct.h>
 #include <linux/efi.h>
 #include <linux/acpi.h>
 #include <linux/kallsyms.h>
@@ -40,6 +41,7 @@
 #include <linux/dmi.h>
 #include <linux/dma-mapping.h>
 #include <linux/ctype.h>
+#include <linux/sort.h>
 #include <linux/uaccess.h>
 #include <linux/init_ohci1394_dma.h>
 
@@ -577,6 +579,205 @@ static int __cpuinit nearby_node(int apicid)
 }
 #endif
 
+#ifdef CONFIG_PCI_MMCONFIG
+struct pci_hostbridge_probe {
+	u32 bus;
+	u32 slot;
+	u32 vendor;
+	u32 device;
+};
+
+static u64 __cpuinitdata fam10h_pci_mmconf_base;
+static int __cpuinitdata fam10h_pci_mmconf_base_status;
+
+static struct pci_hostbridge_probe pci_probes[] __cpuinitdata = {
+	{ 0, 0x18, PCI_VENDOR_ID_AMD, 0x1200 },
+	{ 0xff, 0, PCI_VENDOR_ID_AMD, 0x1200 },
+};
+
+struct range {
+	u64 start;
+	u64 end;
+};
+
+static int __cpuinit cmp_range(const void *x1, const void *x2)
+{
+	const struct range *r1 = x1;
+	const struct range *r2 = x2;
+	int start1, start2;
+
+	start1 = r1->start >> 32;
+	start2 = r2->start >> 32;
+
+	return start1 - start2;
+}
+
+/*[47:0] */
+/* need to avoid (0xfd<<32) and (0xfe<<32), ht used space */
+#define FAM10H_PCI_MMCONF_BASE (0xfcULL<<32)
+#define BASE_VALID(b) ((b != (0xfdULL << 32)) && (b != (0xfeULL << 32)))
+static void __cpuinit get_fam10h_pci_mmconf_base(void)
+{
+	int i;
+	unsigned bus;
+	unsigned slot;
+	int found;
+
+	u64 val;
+	u32 address;
+	u64 tom2;
+	u64 base = FAM10H_PCI_MMCONF_BASE;
+
+	int hi_mmio_num;
+	struct range range[8];
+
+	/* only try to get setting from BSP */
+	/* -1 or 1 */
+	if (fam10h_pci_mmconf_base_status)
+		return;
+
+	if (!early_pci_allowed())
+		goto fail;
+
+	found = 0;
+	for (i = 0; i < ARRAY_SIZE(pci_probes); i++) {
+		u32 id;
+		u16 device;
+		u16 vendor;
+
+		bus = pci_probes[i].bus;
+		slot = pci_probes[i].slot;
+		id = read_pci_config(bus, slot, 0, PCI_VENDOR_ID);
+
+		vendor = id & 0xffff;
+		device = (id>>16) & 0xffff;
+		if (pci_probes[i].vendor == vendor &&
+		    pci_probes[i].device == device) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (!found)
+		goto fail;
+
+	/* SYS_CFG */
+	address = MSR_K8_SYSCFG;
+	rdmsrl(address, val);
+
+	/* TOP_MEM2 is not enabled? */
+	if (!(val & (1<<21))) {
+		tom2 = 0;
+	} else {
+		/* TOP_MEM2 */
+		address = MSR_K8_TOP_MEM2;
+		rdmsrl(address, val);
+		tom2 = val & (0xffffULL<<32);
+	}
+
+	if (base <= tom2)
+		base = tom2 + (1ULL<<32);
+
+	/*
+	 * need to check if the range is in the high mmio range that is
+	 * above 4G
+	 */
+	hi_mmio_num = 0;
+	for (i = 0; i < 8; i++) {
+		u32 reg;
+		u64 start;
+		u64 end;
+		reg = read_pci_config(bus, slot, 1, 0x80 + (i << 3));
+		if (!(reg & 3))
+			continue;
+
+		start = (((u64)reg) << 8) & (0xffULL << 32); /* 39:16 on 31:8*/
+		reg = read_pci_config(bus, slot, 1, 0x84 + (i << 3));
+		end = (((u64)reg) << 8) & (0xffULL << 32); /* 39:16 on 31:8*/
+
+		if (!end)
+			continue;
+
+		range[hi_mmio_num].start = start;
+		range[hi_mmio_num].end = end;
+		hi_mmio_num++;
+	}
+
+	if (!hi_mmio_num)
+		goto out;
+
+	/* sort the range */
+	sort(range, hi_mmio_num, sizeof(struct range), cmp_range, NULL);
+
+	if (range[hi_mmio_num - 1].end < base)
+		goto out;
+	if (range[0].start > base)
+		goto out;
+
+	/* need to find one window */
+	base = range[0].start - (1ULL << 32);
+	if ((base > tom2) && BASE_VALID(base))
+		goto out;
+	base = range[hi_mmio_num - 1].end + (1ULL << 32);
+	if ((base > tom2) && BASE_VALID(base))
+		goto out;
+	/* need to find window between ranges */
+	if (hi_mmio_num > 1)
+	for (i = 0; i < hi_mmio_num - 1; i++) {
+		if (range[i + 1].start > (range[i].end + (1ULL << 32))) {
+			base = range[i].end + (1ULL << 32);
+			if ((base > tom2) && BASE_VALID(base))
+				goto out;
+		}
+	}
+
+fail:
+	fam10h_pci_mmconf_base_status = -1;
+	return;
+out:
+	fam10h_pci_mmconf_base = base;
+	fam10h_pci_mmconf_base_status = 1;
+}
+#endif
+
+static void __cpuinit fam10h_check_enable_mmcfg(struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_PCI_MMCONFIG
+	u64 val;
+	u32 address;
+
+	address = MSR_FAM10H_MMIO_CONF_BASE;
+	rdmsrl(address, val);
+
+	/* try to make sure that AP's setting is identical to BSP setting */
+	if (val & FAM10H_MMIO_CONF_ENABLE) {
+		u64 base;
+		base = val & (0xffffULL << 32);
+		if (fam10h_pci_mmconf_base_status <= 0) {
+			fam10h_pci_mmconf_base = base;
+			fam10h_pci_mmconf_base_status = 1;
+			return;
+		} else if (fam10h_pci_mmconf_base ==  base)
+			return;
+	}
+
+	/*
+	 * if it is not enabled, try to enable it and assume only one segment
+	 * with 256 buses
+	 */
+	get_fam10h_pci_mmconf_base();
+	if (fam10h_pci_mmconf_base_status <= 0)
+		return;
+
+	printk(KERN_INFO "Enable MMCONFIG on AMD Family 10h\n");
+	val &= ~((FAM10H_MMIO_CONF_BASE_MASK<<FAM10H_MMIO_CONF_BASE_SHIFT) |
+	     (FAM10H_MMIO_CONF_BUSRANGE_MASK<<FAM10H_MMIO_CONF_BUSRANGE_SHIFT));
+	val |= fam10h_pci_mmconf_base | (8 << FAM10H_MMIO_CONF_BUSRANGE_SHIFT) |
+	       FAM10H_MMIO_CONF_ENABLE;
+	wrmsrl(address, val);
+#endif
+}
+
 /*
  * 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.
@@ -760,6 +961,9 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
 	/* MFENCE stops RDTSC speculation */
 	set_cpu_cap(c, X86_FEATURE_MFENCE_RDTSC);
 
+	if (c->x86 == 0x10)
+		fam10h_check_enable_mmcfg(c);
+
 	if (amd_apic_timer_broken())
 		disable_apic_timer = 1;