x86: add PCI extended config space access for AMD Barcelona

This patch implements PCI extended configuration space access for
AMD's Barcelona CPUs. It extends the method using CF8/CFC IO
addresses. An x86 capability bit has been introduced that is set for
CPUs supporting PCI extended config space accesses.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/cpu/amd.c

@@ -6,6 +6,7 @@
 #include <asm/apic.h>
 
 #include <mach_apic.h>
+#include "../setup.h"
 #include "cpu.h"
 
 /*
@@ -308,6 +309,9 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
 
 	if (cpu_has_xmm2)
 		set_cpu_cap(c, X86_FEATURE_MFENCE_RDTSC);
+
+	if (c->x86 == 0x10)
+		amd_enable_pci_ext_cfg(c);
 }
 
 static unsigned int __cpuinit amd_size_cache(struct cpuinfo_x86 *c, unsigned int size)

arch/x86/kernel/cpu/amd_64.c

@@ -217,6 +217,9 @@ void __cpuinit init_amd(struct cpuinfo_x86 *c)
 	if (c->x86 == 0x10)
 		fam10h_check_enable_mmcfg();
 
+	if (c->x86 == 0x10)
+		amd_enable_pci_ext_cfg(c);
+
 	if (amd_apic_timer_broken())
 		disable_apic_timer = 1;
 

arch/x86/kernel/setup.c

@@ -136,4 +136,17 @@ void __init setup_per_cpu_areas(void)
 	setup_cpumask_of_cpu();
 }
 
+#define ENABLE_CF8_EXT_CFG      (1ULL << 46)
+
+void __cpuinit amd_enable_pci_ext_cfg(struct cpuinfo_x86 *c)
+{
+	u64 reg;
+	rdmsrl(MSR_AMD64_NB_CFG, reg);
+	if (!(reg & ENABLE_CF8_EXT_CFG)) {
+		reg |= ENABLE_CF8_EXT_CFG;
+		wrmsrl(MSR_AMD64_NB_CFG, reg);
+	}
+	set_cpu_cap(c, X86_FEATURE_PCI_EXT_CFG);
+}
+
 #endif

arch/x86/kernel/setup.h

@@ -0,0 +1,26 @@
+/*
+ * Internal declarations for shared x86 setup code.
+ *
+ * Copyright (c) 2008 Advanced Micro Devices, Inc.
+ * Contributed by Robert Richter <robert.richter@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307 USA
+ */
+
+#ifndef _ARCH_X86_KERNEL_SETUP_H
+
+extern void __cpuinit amd_enable_pci_ext_cfg(struct cpuinfo_x86 *c);
+
+#endif	/* _ARCH_X86_KERNEL_SETUP_H */

arch/x86/kernel/setup_64.c

@@ -73,6 +73,8 @@
 #include <asm/pat.h>
 #include <asm/mmconfig.h>
 
+#include "setup.h"
+
 #include <mach_apic.h>
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>

arch/x86/pci/direct.c

@@ -8,18 +8,21 @@
 #include "pci.h"
 
 /*
- * Functions for accessing PCI configuration space with type 1 accesses
+ * Functions for accessing PCI base (first 256 bytes) and extended
+ * (4096 bytes per PCI function) configuration space with type 1
+ * accesses.
  */
 
 #define PCI_CONF1_ADDRESS(bus, devfn, reg) \
-	(0x80000000 | (bus << 16) | (devfn << 8) | (reg & ~3))
+	(0x80000000 | ((reg & 0xF00) << 16) | (bus << 16) \
+	| (devfn << 8) | (reg & 0xFC))
 
 static int pci_conf1_read(unsigned int seg, unsigned int bus,
 			  unsigned int devfn, int reg, int len, u32 *value)
 {
 	unsigned long flags;
 
-	if ((bus > 255) || (devfn > 255) || (reg > 255)) {
+	if ((bus > 255) || (devfn > 255) || (reg > 4095)) {
 		*value = -1;
 		return -EINVAL;
 	}
@@ -50,7 +53,7 @@ static int pci_conf1_write(unsigned int seg, unsigned int bus,
 {
 	unsigned long flags;
 
-	if ((bus > 255) || (devfn > 255) || (reg > 255)) 
+	if ((bus > 255) || (devfn > 255) || (reg > 4095))
 		return -EINVAL;
 
 	spin_lock_irqsave(&pci_config_lock, flags);
@@ -260,10 +263,16 @@ void __init pci_direct_init(int type)
 		return;
 	printk(KERN_INFO "PCI: Using configuration type %d for base access\n",
 		 type);
-	if (type == 1)
+	if (type == 1) {
 		raw_pci_ops = &pci_direct_conf1;
-	else
+		if (!raw_pci_ext_ops && cpu_has_pci_ext_cfg) {
+			printk(KERN_INFO "PCI: Using configuration type 1 "
+			       "for extended access\n");
+			raw_pci_ext_ops = &pci_direct_conf1;
+		}
+	} else {
 		raw_pci_ops = &pci_direct_conf2;
+	}
 }
 
 int __init pci_direct_probe(void)

include/asm-x86/cpufeature.h

@@ -79,6 +79,7 @@
 #define X86_FEATURE_REP_GOOD	(3*32+16) /* rep microcode works well on this CPU */
 #define X86_FEATURE_MFENCE_RDTSC (3*32+17) /* Mfence synchronizes RDTSC */
 #define X86_FEATURE_LFENCE_RDTSC (3*32+18) /* Lfence synchronizes RDTSC */
+#define X86_FEATURE_PCI_EXT_CFG	(3*32+19) /* PCI extended cfg access */
 
 /* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */
 #define X86_FEATURE_XMM3	(4*32+ 0) /* Streaming SIMD Extensions-3 */
@@ -187,6 +188,7 @@ extern const char * const x86_power_flags[32];
 #define cpu_has_gbpages		boot_cpu_has(X86_FEATURE_GBPAGES)
 #define cpu_has_arch_perfmon	boot_cpu_has(X86_FEATURE_ARCH_PERFMON)
 #define cpu_has_pat		boot_cpu_has(X86_FEATURE_PAT)
+#define cpu_has_pci_ext_cfg	boot_cpu_has(X86_FEATURE_PCI_EXT_CFG)
 
 #if defined(CONFIG_X86_INVLPG) || defined(CONFIG_X86_64)
 # define cpu_has_invlpg		1