[PATCH] i386/x86_64: Check if MCFG works for the first 16 busses

Previously only the first bus would be checked against Type 1.

Why 16? Checking all would need too much memory and we
can assume that systems with more than 16 busses have better than
average quality BIOS.

This is an additional defense against bad MCFG tables.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 30 insertions, 22 deletions

diff --git a/arch/i386/pci/mmconfig.c b/arch/i386/pci/mmconfig.c
index ee815c7d3e4..2002c741a38 100644
--- a/arch/i386/pci/mmconfig.c
+++ b/arch/i386/pci/mmconfig.c
@@ -17,12 +17,15 @@
 
 #define MMCONFIG_APER_SIZE (256*1024*1024)
 
+/* Assume systems with more busses have correct MCFG */
+#define MAX_CHECK_BUS 16
+
 #define mmcfg_virt_addr ((void __iomem *) fix_to_virt(FIX_PCIE_MCFG))
 
 /* The base address of the last MMCONFIG device accessed */
 static u32 mmcfg_last_accessed_device;
 
-static DECLARE_BITMAP(fallback_slots, 32);
+static DECLARE_BITMAP(fallback_slots, MAX_CHECK_BUS*32);
 
 /*
  * Functions for accessing PCI configuration space with MMCONFIG accesses
@@ -32,8 +35,8 @@ static u32 get_base_addr(unsigned int seg, int bus, unsigned devfn)
 	int cfg_num = -1;
 	struct acpi_table_mcfg_config *cfg;
 
-	if (seg == 0 && bus == 0 &&
-	    test_bit(PCI_SLOT(devfn), fallback_slots))
+	if (seg == 0 && bus < MAX_CHECK_BUS &&
+	    test_bit(PCI_SLOT(devfn) + 32*bus, fallback_slots))
 		return 0;
 
 	while (1) {
@@ -149,29 +152,34 @@ static struct pci_raw_ops pci_mmcfg = {
    Normally this can be expressed in the MCFG by not listing them
    and assigning suitable _SEGs, but this isn't implemented in some BIOS.
    Instead try to discover all devices on bus 0 that are unreachable using MM
-   and fallback for them.
-   We only do this for bus 0/seg 0 */
+   and fallback for them. */
 static __init void unreachable_devices(void)
 {
-	int i;
+	int i, k;
 	unsigned long flags;
 
-	for (i = 0; i < 32; i++) {
-		u32 val1;
-		u32 addr;
-
-		pci_conf1_read(0, 0, PCI_DEVFN(i, 0), 0, 4, &val1);
-		if (val1 == 0xffffffff)
-			continue;
-
-		/* Locking probably not needed, but safer */
-		spin_lock_irqsave(&pci_config_lock, flags);
-		addr = get_base_addr(0, 0, PCI_DEVFN(i, 0));
-		if (addr != 0)
-			pci_exp_set_dev_base(addr, 0, PCI_DEVFN(i, 0));
-		if (addr == 0 || readl((u32 __iomem *)mmcfg_virt_addr) != val1)
-			set_bit(i, fallback_slots);
-		spin_unlock_irqrestore(&pci_config_lock, flags);
+	for (k = 0; k < MAX_CHECK_BUS; k++) {
+		for (i = 0; i < 32; i++) {
+			u32 val1;
+			u32 addr;
+
+			pci_conf1_read(0, k, PCI_DEVFN(i, 0), 0, 4, &val1);
+			if (val1 == 0xffffffff)
+				continue;
+
+			/* Locking probably not needed, but safer */
+			spin_lock_irqsave(&pci_config_lock, flags);
+			addr = get_base_addr(0, k, PCI_DEVFN(i, 0));
+			if (addr != 0)
+				pci_exp_set_dev_base(addr, k, PCI_DEVFN(i, 0));
+			if (addr == 0 ||
+			    readl((u32 __iomem *)mmcfg_virt_addr) != val1) {
+				set_bit(i, fallback_slots);
+				printk(KERN_NOTICE
+			"PCI: No mmconfig possible on %x:%x\n", k, i);
+			}
+			spin_unlock_irqrestore(&pci_config_lock, flags);
+		}
 	}
 }