drm/i915, agp/intel: Fix stolen memory size on Sandybridge

New memory control config reg at 0x50 should be used for stolen
memory size detection on Sandybridge.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 74 insertions, 4 deletions

diff --git a/drivers/char/agp/intel-agp.c b/drivers/char/agp/intel-agp.c
index c3c870bf5678..9a551bc34c39 100644
--- a/drivers/char/agp/intel-agp.c
+++ b/drivers/char/agp/intel-agp.c
@@ -150,6 +150,25 @@ extern int agp_memory_reserved;
 #define INTEL_I7505_AGPCTRL     0x70
 #define INTEL_I7505_MCHCFG      0x50
 
+#define SNB_GMCH_CTRL   0x50
+#define SNB_GMCH_GMS_STOLEN_MASK        0xF8
+#define SNB_GMCH_GMS_STOLEN_32M         (1 << 3)
+#define SNB_GMCH_GMS_STOLEN_64M         (2 << 3)
+#define SNB_GMCH_GMS_STOLEN_96M         (3 << 3)
+#define SNB_GMCH_GMS_STOLEN_128M        (4 << 3)
+#define SNB_GMCH_GMS_STOLEN_160M        (5 << 3)
+#define SNB_GMCH_GMS_STOLEN_192M        (6 << 3)
+#define SNB_GMCH_GMS_STOLEN_224M        (7 << 3)
+#define SNB_GMCH_GMS_STOLEN_256M        (8 << 3)
+#define SNB_GMCH_GMS_STOLEN_288M        (9 << 3)
+#define SNB_GMCH_GMS_STOLEN_320M        (0xa << 3)
+#define SNB_GMCH_GMS_STOLEN_352M        (0xb << 3)
+#define SNB_GMCH_GMS_STOLEN_384M        (0xc << 3)
+#define SNB_GMCH_GMS_STOLEN_416M        (0xd << 3)
+#define SNB_GMCH_GMS_STOLEN_448M        (0xe << 3)
+#define SNB_GMCH_GMS_STOLEN_480M        (0xf << 3)
+#define SNB_GMCH_GMS_STOLEN_512M        (0x10 << 3)
+
 static const struct aper_size_info_fixed intel_i810_sizes[] =
 {
         {64, 16384, 4},
@@ -621,7 +640,7 @@ static struct aper_size_info_fixed intel_i830_sizes[] =
 static void intel_i830_init_gtt_entries(void)
 {
         u16 gmch_ctrl;
-        int gtt_entries;
+        int gtt_entries = 0;
         u8 rdct;
         int local = 0;
         static const int ddt[4] = { 0, 16, 32, 64 };
@@ -715,10 +734,61 @@ static void intel_i830_init_gtt_entries(void)
                 }
         } else if (agp_bridge->dev->device ==
                    PCI_DEVICE_ID_INTEL_SANDYBRIDGE_HB) {
-                /* XXX: This is what my A1 silicon has.  What's the right
-                 * answer?
+                /*
+                 * SandyBridge has new memory control reg at 0x50.w
                  */
-                gtt_entries = MB(64) - KB(size);
+                u16 snb_gmch_ctl;
+                pci_read_config_word(intel_private.pcidev, SNB_GMCH_CTRL, &snb_gmch_ctl);
+                switch (snb_gmch_ctl & SNB_GMCH_GMS_STOLEN_MASK) {
+                case SNB_GMCH_GMS_STOLEN_32M:
+                        gtt_entries = MB(32) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_64M:
+                        gtt_entries = MB(64) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_96M:
+                        gtt_entries = MB(96) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_128M:
+                        gtt_entries = MB(128) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_160M:
+                        gtt_entries = MB(160) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_192M:
+                        gtt_entries = MB(192) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_224M:
+                        gtt_entries = MB(224) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_256M:
+                        gtt_entries = MB(256) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_288M:
+                        gtt_entries = MB(288) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_320M:
+                        gtt_entries = MB(320) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_352M:
+                        gtt_entries = MB(352) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_384M:
+                        gtt_entries = MB(384) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_416M:
+                        gtt_entries = MB(416) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_448M:
+                        gtt_entries = MB(448) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_480M:
+                        gtt_entries = MB(480) - KB(size);
+                        break;
+                case SNB_GMCH_GMS_STOLEN_512M:
+                        gtt_entries = MB(512) - KB(size);
+                        break;
+                }
         } else {
                 switch (gmch_ctrl & I855_GMCH_GMS_MASK) {
                 case I855_GMCH_GMS_STOLEN_1M: