From: Tony Camuso <tcamuso@redhat.com>
Date: Fri, 6 Jun 2008 14:02:18 -0400
Subject: [pci] mmconfig: use conf1 for access below 256 bytes
Message-id: 48497BAA.8020502@redhat.com
O-Subject: [RHEL5.3 PATCH 3/3] PCI MMCONFIG: Always use conf1 to access config space below 256 bytes
Bugzilla: 441615 251493
RH-Acked-by: Alan Cox <alan@redhat.com>

commit b369611677d61a1a592c6f8c599d7dd8c485064f
Author: Tony Camuso <tony.camuso@hp.com>
Date:   Tue Jun 3 14:51:04 2008 -0400

     PCI always use conf1 to access config space below 256 bytes

     This patch eliminates all known mmconfig problems by using the
     conf1 mechanism to access PCI config space below 256 bytes.

     Upstream commit: a0ca9909609470ad779b9b9cc68ce96e975afff7

  arch/i386/pci/mmconfig.c   |   57 +++++++-------------------------------------
  arch/i386/pci/pci.h        |    8 ------
  arch/x86_64/pci/mmconfig.c |   51 +++++++-------------------------------
  3 files changed, 19 insertions(+), 97 deletions(-)

     Signed-off-by: Tony Camuso <tcamuso@redhat.com>

diff --git a/arch/i386/pci/mmconfig.c b/arch/i386/pci/mmconfig.c
index 4542946..1d4a73d 100644
--- a/arch/i386/pci/mmconfig.c
+++ b/arch/i386/pci/mmconfig.c
@@ -25,8 +25,6 @@
 /* The base address of the last MMCONFIG device accessed */
 static u32 mmcfg_last_accessed_device;
 
-static DECLARE_BITMAP(fallback_slots, MAX_CHECK_BUS*32);
-
 /*
  * Functions for accessing PCI configuration space with MMCONFIG accesses
  */
@@ -35,10 +33,6 @@ 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 < MAX_CHECK_BUS &&
-	    test_bit(PCI_SLOT(devfn) + 32*bus, fallback_slots))
-		return 0;
-
 	while (1) {
 		++cfg_num;
 		if (cfg_num >= pci_mmcfg_config_num) {
@@ -81,13 +75,16 @@ static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
 	u32 base;
 
 	if ((bus > 255) || (devfn > 255) || (reg > 4095)) {
-		*value = -1;
+err:		*value = -1;
 		return -EINVAL;
 	}
 
+	if (reg < 256)
+		return pci_conf1_read(seg,bus,devfn,reg,len,value);
+
 	base = get_base_addr(seg, bus, devfn);
 	if (!base)
-		return pci_conf1_read(seg,bus,devfn,reg,len,value);
+		goto err;
 
 	spin_lock_irqsave(&pci_config_lock, flags);
 
@@ -119,9 +116,12 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
 	if ((bus > 255) || (devfn > 255) || (reg > 4095)) 
 		return -EINVAL;
 
+	if (reg < 256)
+		return pci_conf1_write(seg,bus,devfn,reg,len,value);
+
 	base = get_base_addr(seg, bus, devfn);
 	if (!base)
-		return pci_conf1_write(seg,bus,devfn,reg,len,value);
+		return -EINVAL;
 
 	spin_lock_irqsave(&pci_config_lock, flags);
 
@@ -149,46 +149,8 @@ static struct pci_raw_ops pci_mmcfg = {
 	.write =	pci_mmcfg_write,
 };
 
-/* K8 systems have some devices (typically in the builtin northbridge)
-   that are only accessible using type1
-   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. */
-static __init void unreachable_devices(void)
-{
-	int i, k;
-	unsigned long 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 + 32*k, fallback_slots);
-				printk(KERN_NOTICE
-			"PCI: No mmconfig possible on %x:%x\n", k, i);
-			}
-			spin_unlock_irqrestore(&pci_config_lock, flags);
-		}
-	}
-}
-
 void __init pci_mmcfg_init(void)
 {
-	dmi_check_system(nommconf_dmi_table);
-
 	if ((pci_probe & PCI_PROBE_MMCONF) == 0)
 		return;
 
@@ -211,5 +173,4 @@ void __init pci_mmcfg_init(void)
 	raw_pci_ops = &pci_mmcfg;
 	pci_probe = pci_probe & ~PCI_PROBE_MASK;
 	pci_probe = pci_probe | PCI_PROBE_MMCONF | PCI_USING_MMCONF;
-	unreachable_devices();
 }
diff --git a/arch/i386/pci/pci.h b/arch/i386/pci/pci.h
index 301a7a5..932f39e 100644
--- a/arch/i386/pci/pci.h
+++ b/arch/i386/pci/pci.h
@@ -30,14 +30,6 @@
 #define PCI_USING_MMCONF	0x20000
 #define PCI_NOASSIGN_ROMS	0x40000
 
-/*
- * The first 16 buses are checked for MMCONF compliance. A bitmap is
- * created and checked on every pci config access to these buses in
- * systems having MMCONF as the system-wide default pci config access
- * mechanism.
- */
-#define MAX_CHECK_BUS 16
-
 extern unsigned int pci_probe;
 extern unsigned long pirq_table_addr;
 
diff --git a/arch/x86_64/pci/mmconfig.c b/arch/x86_64/pci/mmconfig.c
index 4987502..ec40acb 100644
--- a/arch/x86_64/pci/mmconfig.c
+++ b/arch/x86_64/pci/mmconfig.c
@@ -18,8 +18,6 @@
 #define MMCONFIG_APER_MIN	(2 * 1024*1024)
 #define MMCONFIG_APER_MAX	(256 * 1024*1024)
 
-static DECLARE_BITMAP(fallback_slots, 32*MAX_CHECK_BUS);
-
 /* Static virtual mapping of the MMCONFIG aperture */
 struct mmcfg_virt {
 	struct acpi_table_mcfg_config *cfg;
@@ -60,9 +58,7 @@ static char __iomem *get_virt(unsigned int seg, unsigned bus)
 static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
 {
 	char __iomem *addr;
-	if (seg == 0 && bus < MAX_CHECK_BUS &&
-		test_bit(32*bus + PCI_SLOT(devfn), fallback_slots))
-		return NULL;
+
 	addr = get_virt(seg, bus);
 	if (!addr)
 		return NULL;
@@ -76,13 +72,16 @@ static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
 
 	/* Why do we have this when nobody checks it. How about a BUG()!? -AK */
 	if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
-		*value = -1;
+err:		*value = -1;
 		return -EINVAL;
 	}
 
+	if (reg < 256)
+		return pci_conf1_read(seg,bus,devfn,reg,len,value);
+
 	addr = pci_dev_base(seg, bus, devfn);
 	if (!addr)
-		return pci_conf1_read(seg,bus,devfn,reg,len,value);
+		goto err;
 
 	switch (len) {
 	case 1:
@@ -108,9 +107,12 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
 	if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
 		return -EINVAL;
 
+	if (reg < 256)
+		return pci_conf1_write(seg,bus,devfn,reg,len,value);
+
 	addr = pci_dev_base(seg, bus, devfn);
 	if (!addr)
-		return pci_conf1_write(seg,bus,devfn,reg,len,value);
+		return -EINVAL;
 
 	switch (len) {
 	case 1:
@@ -132,41 +134,10 @@ static struct pci_raw_ops pci_mmcfg = {
 	.write =	pci_mmcfg_write,
 };
 
-/* K8 systems have some devices (typically in the builtin northbridge)
-   that are only accessible using type1
-   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. */
-static __init void unreachable_devices(void)
-{
-	int i, k;
-	/* Use the max bus number from ACPI here? */
-	for (k = 0; k < MAX_CHECK_BUS; k++) {
-		for (i = 0; i < 32; i++) {
-			u32 val1;
-			char __iomem *addr;
-
-			pci_conf1_read(0, k, PCI_DEVFN(i,0), 0, 4, &val1);
-			if (val1 == 0xffffffff)
-				continue;
-			addr = pci_dev_base(0, k, PCI_DEVFN(i, 0));
-			if (addr == NULL|| readl(addr) != val1) {
-				set_bit(i + 32*k, fallback_slots);
-				printk(KERN_NOTICE
-				"PCI: No mmconfig possible on device %x:%x\n",
-					k, i);
-			}
-		}
-	}
-}
-
 void __init pci_mmcfg_init(void)
 {
 	int i;
 
-	dmi_check_system(nommconf_dmi_table);
-
 	if ((pci_probe & PCI_PROBE_MMCONF) == 0)
 		return;
 
@@ -203,8 +174,6 @@ void __init pci_mmcfg_init(void)
 		printk(KERN_INFO "PCI: Using MMCONFIG at %x\n", pci_mmcfg_config[i].base_address);
 	}
 
-	unreachable_devices();
-
 	raw_pci_ops = &pci_mmcfg;
 	pci_probe = pci_probe & ~PCI_PROBE_MASK;
 	pci_probe = pci_probe | PCI_PROBE_MMCONF | PCI_USING_MMCONF;