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>

1 files changed, 30 insertions, 22 deletions

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;