x86, k8-gart: Decouple handling of garts and northbridges

So far we only provide num_k8_northbridges. This is required in
different areas (e.g. L3 cache index disable, GART). But not all AMD
CPUs provide a GART. Thus it is useful to split off the GART handling
from the generic caching of AMD northbridge misc devices.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
LKML-Reference: <20100917160254.GC4958@loge.amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

3 files changed, 50 insertions, 33 deletions

diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c
index 2521cdcb877e..6fdfb0b20f8c 100644
--- a/arch/x86/kernel/cpu/intel_cacheinfo.c
+++ b/arch/x86/kernel/cpu/intel_cacheinfo.c
@@ -369,7 +369,7 @@ static void __cpuinit amd_check_l3_disable(struct _cpuid4_info_regs *this_leaf,
                         return;
 
         /* not in virtualized environments */
-        if (num_k8_northbridges == 0)
+        if (k8_northbridges.num == 0)
                 return;
 
         /*
@@ -377,7 +377,7 @@ static void __cpuinit amd_check_l3_disable(struct _cpuid4_info_regs *this_leaf,
          * never freed but this is done only on shutdown so it doesn't matter.
          */
         if (!l3_caches) {
-                int size = num_k8_northbridges * sizeof(struct amd_l3_cache *);
+                int size = k8_northbridges.num * sizeof(struct amd_l3_cache *);
 
                 l3_caches = kzalloc(size, GFP_ATOMIC);
                 if (!l3_caches)
diff --git a/arch/x86/kernel/k8.c b/arch/x86/kernel/k8.c
index 0f7bc20cfcde..5de1b6b39639 100644
--- a/arch/x86/kernel/k8.c
+++ b/arch/x86/kernel/k8.c
@@ -10,9 +10,6 @@
 #include <linux/spinlock.h>
 #include <asm/k8.h>
 
-int num_k8_northbridges;
-EXPORT_SYMBOL(num_k8_northbridges);
-
 static u32 *flush_words;
 
 struct pci_device_id k8_nb_ids[] = {
@@ -22,7 +19,7 @@ struct pci_device_id k8_nb_ids[] = {
 };
 EXPORT_SYMBOL(k8_nb_ids);
 
-struct pci_dev **k8_northbridges;
+struct k8_northbridge_info k8_northbridges;
 EXPORT_SYMBOL(k8_northbridges);
 
 static struct pci_dev *next_k8_northbridge(struct pci_dev *dev)
@@ -40,36 +37,44 @@ int cache_k8_northbridges(void)
         int i;
         struct pci_dev *dev;
 
-        if (num_k8_northbridges)
+        if (k8_northbridges.num)
                 return 0;
 
         dev = NULL;
         while ((dev = next_k8_northbridge(dev)) != NULL)
-                num_k8_northbridges++;
+                k8_northbridges.num++;
+
+        /* some CPU families (e.g. family 0x11) do not support GART */
+        if (boot_cpu_data.x86 == 0xf || boot_cpu_data.x86 == 0x10)
+                k8_northbridges.gart_supported = 1;
 
-        k8_northbridges = kmalloc((num_k8_northbridges + 1) * sizeof(void *),
-                                  GFP_KERNEL);
-        if (!k8_northbridges)
+        k8_northbridges.nb_misc = kmalloc((k8_northbridges.num + 1) *
+                                          sizeof(void *), GFP_KERNEL);
+        if (!k8_northbridges.nb_misc)
                 return -ENOMEM;
 
-        if (!num_k8_northbridges) {
-                k8_northbridges[0] = NULL;
+        if (!k8_northbridges.num) {
+                k8_northbridges.nb_misc[0] = NULL;
                 return 0;
         }
 
-        flush_words = kmalloc(num_k8_northbridges * sizeof(u32), GFP_KERNEL);
-        if (!flush_words) {
-                kfree(k8_northbridges);
-                return -ENOMEM;
+        if (k8_northbridges.gart_supported) {
+                flush_words = kmalloc(k8_northbridges.num * sizeof(u32),
+                                      GFP_KERNEL);
+                if (!flush_words) {
+                        kfree(k8_northbridges.nb_misc);
+                        return -ENOMEM;
+                }
         }
 
         dev = NULL;
         i = 0;
         while ((dev = next_k8_northbridge(dev)) != NULL) {
-                k8_northbridges[i] = dev;
-                pci_read_config_dword(dev, 0x9c, &flush_words[i++]);
+                k8_northbridges.nb_misc[i] = dev;
+                if (k8_northbridges.gart_supported)
+                        pci_read_config_dword(dev, 0x9c, &flush_words[i++]);
         }
-        k8_northbridges[i] = NULL;
+        k8_northbridges.nb_misc[i] = NULL;
         return 0;
 }
 EXPORT_SYMBOL_GPL(cache_k8_northbridges);
@@ -93,22 +98,25 @@ void k8_flush_garts(void)
         unsigned long flags;
         static DEFINE_SPINLOCK(gart_lock);
 
+        if (!k8_northbridges.gart_supported)
+                return;
+
         /* Avoid races between AGP and IOMMU. In theory it's not needed
            but I'm not sure if the hardware won't lose flush requests
            when another is pending. This whole thing is so expensive anyways
            that it doesn't matter to serialize more. -AK */
         spin_lock_irqsave(&gart_lock, flags);
         flushed = 0;
-        for (i = 0; i < num_k8_northbridges; i++) {
-                pci_write_config_dword(k8_northbridges[i], 0x9c,
+        for (i = 0; i < k8_northbridges.num; i++) {
+                pci_write_config_dword(k8_northbridges.nb_misc[i], 0x9c,
                                        flush_words[i]|1);
                 flushed++;
         }
-        for (i = 0; i < num_k8_northbridges; i++) {
+        for (i = 0; i < k8_northbridges.num; i++) {
                 u32 w;
                 /* Make sure the hardware actually executed the flush*/
                 for (;;) {
-                        pci_read_config_dword(k8_northbridges[i],
+                        pci_read_config_dword(k8_northbridges.nb_misc[i],
                                               0x9c, &w);
                         if (!(w & 1))
                                 break;
diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index 0f7f130caa67..8f214a2643fa 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -560,8 +560,11 @@ static void enable_gart_translations(void)
 {
         int i;
 
-        for (i = 0; i < num_k8_northbridges; i++) {
-                struct pci_dev *dev = k8_northbridges[i];
+        if (!k8_northbridges.gart_supported)
+                return;
+
+        for (i = 0; i < k8_northbridges.num; i++) {
+                struct pci_dev *dev = k8_northbridges.nb_misc[i];
 
                 enable_gart_translation(dev, __pa(agp_gatt_table));
         }
@@ -592,10 +595,13 @@ static void gart_fixup_northbridges(struct sys_device *dev)
         if (!fix_up_north_bridges)
                 return;
 
+        if (!k8_northbridges.gart_supported)
+                return;
+
         pr_info("PCI-DMA: Restoring GART aperture settings\n");
 
-        for (i = 0; i < num_k8_northbridges; i++) {
-                struct pci_dev *dev = k8_northbridges[i];
+        for (i = 0; i < k8_northbridges.num; i++) {
+                struct pci_dev *dev = k8_northbridges.nb_misc[i];
 
                 /*
                  * Don't enable translations just yet.  That is the next
@@ -649,8 +655,8 @@ static __init int init_k8_gatt(struct agp_kern_info *info)
 
         aper_size = aper_base = info->aper_size = 0;
         dev = NULL;
-        for (i = 0; i < num_k8_northbridges; i++) {
-                dev = k8_northbridges[i];
+        for (i = 0; i < k8_northbridges.num; i++) {
+                dev = k8_northbridges.nb_misc[i];
                 new_aper_base = read_aperture(dev, &new_aper_size);
                 if (!new_aper_base)
                         goto nommu;
@@ -718,10 +724,13 @@ static void gart_iommu_shutdown(void)
         if (!no_agp)
                 return;
 
-        for (i = 0; i < num_k8_northbridges; i++) {
+        if (!k8_northbridges.gart_supported)
+                return;
+
+        for (i = 0; i < k8_northbridges.num; i++) {
                 u32 ctl;
 
-                dev = k8_northbridges[i];
+                dev = k8_northbridges.nb_misc[i];
                 pci_read_config_dword(dev, AMD64_GARTAPERTURECTL, &ctl);
 
                 ctl &= ~GARTEN;
@@ -739,7 +748,7 @@ int __init gart_iommu_init(void)
         unsigned long scratch;
         long i;
 
-        if (num_k8_northbridges == 0)
+        if (!k8_northbridges.gart_supported)
                 return 0;
 
 #ifndef CONFIG_AGP_AMD64