agp: use scratch page on memory remove and at GATT creation V4

Convert most AGP chipset to use scratch page as default entries.
This help avoiding GPU querying 0 address and trigger computer
fault. With KMS and memory manager we bind/unbind AGP memory
constantly and it seems that some GPU are still doing AGP
traffic even after GPU report being idle with the memory segment.

Tested (radeon GPU KMS + Xorg + compiz + glxgears + quake3) on :
- SIS 1039:0001 & 1039:0003
- Intel 865 8086:2571

Compile tested for other bridges

V2 enable scratch page on uninorth
V3 fix unbound check in uninorth insert memory (Michel Dänzer)
V4 rebase on top of drm-next branch with the lastest intel AGP
   changeset (stable should use version V3 of the patch)

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/char/agp/ali-agp.c

@@ -204,6 +204,7 @@ static const struct agp_bridge_driver ali_generic_bridge = {
 	.aperture_sizes		= ali_generic_sizes,
 	.size_type		= U32_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= ali_configure,
 	.fetch_size		= ali_fetch_size,
 	.cleanup		= ali_cleanup,

drivers/char/agp/amd-k7-agp.c

@@ -142,6 +142,7 @@ static int amd_create_gatt_table(struct agp_bridge_data *bridge)
 {
 	struct aper_size_info_lvl2 *value;
 	struct amd_page_map page_dir;
+	unsigned long __iomem *cur_gatt;
 	unsigned long addr;
 	int retval;
 	u32 temp;
@@ -178,6 +179,13 @@ static int amd_create_gatt_table(struct agp_bridge_data *bridge)
 		readl(page_dir.remapped+GET_PAGE_DIR_OFF(addr));	/* PCI Posting. */
 	}
 
+	for (i = 0; i < value->num_entries; i++) {
+		addr = (i * PAGE_SIZE) + agp_bridge->gart_bus_addr;
+		cur_gatt = GET_GATT(addr);
+		writel(agp_bridge->scratch_page, cur_gatt+GET_GATT_OFF(addr));
+		readl(cur_gatt+GET_GATT_OFF(addr));	/* PCI Posting. */
+	}
+
 	return 0;
 }
 
@@ -375,6 +383,7 @@ static const struct agp_bridge_driver amd_irongate_driver = {
 	.aperture_sizes		= amd_irongate_sizes,
 	.size_type		= LVL2_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= amd_irongate_configure,
 	.fetch_size		= amd_irongate_fetch_size,
 	.cleanup		= amd_irongate_cleanup,

drivers/char/agp/amd64-agp.c

@@ -210,6 +210,7 @@ static const struct agp_bridge_driver amd_8151_driver = {
 	.aperture_sizes		= amd_8151_sizes,
 	.size_type		= U32_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= amd_8151_configure,
 	.fetch_size		= amd64_fetch_size,
 	.cleanup		= amd64_cleanup,

drivers/char/agp/ati-agp.c

@@ -341,6 +341,7 @@ static int ati_create_gatt_table(struct agp_bridge_data *bridge)
 {
 	struct aper_size_info_lvl2 *value;
 	struct ati_page_map page_dir;
+	unsigned long __iomem *cur_gatt;
 	unsigned long addr;
 	int retval;
 	u32 temp;
@@ -395,6 +396,12 @@ static int ati_create_gatt_table(struct agp_bridge_data *bridge)
 		readl(page_dir.remapped+GET_PAGE_DIR_OFF(addr));	/* PCI Posting. */
 	}
 
+	for (i = 0; i < value->num_entries; i++) {
+		addr = (i * PAGE_SIZE) + agp_bridge->gart_bus_addr;
+		cur_gatt = GET_GATT(addr);
+		writel(agp_bridge->scratch_page, cur_gatt+GET_GATT_OFF(addr));
+	}
+
 	return 0;
 }
 
@@ -415,6 +422,7 @@ static const struct agp_bridge_driver ati_generic_bridge = {
 	.aperture_sizes		= ati_generic_sizes,
 	.size_type		= LVL2_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= ati_configure,
 	.fetch_size		= ati_fetch_size,
 	.cleanup		= ati_cleanup,

drivers/char/agp/intel-agp.c

@@ -464,6 +464,7 @@ static const struct agp_bridge_driver intel_generic_driver = {
 	.aperture_sizes		= intel_generic_sizes,
 	.size_type		= U16_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= intel_configure,
 	.fetch_size		= intel_fetch_size,
 	.cleanup		= intel_cleanup,
@@ -490,6 +491,7 @@ static const struct agp_bridge_driver intel_815_driver = {
 	.aperture_sizes		= intel_815_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 2,
+	.needs_scratch_page	= true,
 	.configure		= intel_815_configure,
 	.fetch_size		= intel_815_fetch_size,
 	.cleanup		= intel_8xx_cleanup,
@@ -516,6 +518,7 @@ static const struct agp_bridge_driver intel_820_driver = {
 	.aperture_sizes		= intel_8xx_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= intel_820_configure,
 	.fetch_size		= intel_8xx_fetch_size,
 	.cleanup		= intel_820_cleanup,
@@ -542,6 +545,7 @@ static const struct agp_bridge_driver intel_830mp_driver = {
 	.aperture_sizes		= intel_830mp_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 4,
+	.needs_scratch_page	= true,
 	.configure		= intel_830mp_configure,
 	.fetch_size		= intel_8xx_fetch_size,
 	.cleanup		= intel_8xx_cleanup,
@@ -568,6 +572,7 @@ static const struct agp_bridge_driver intel_840_driver = {
 	.aperture_sizes		= intel_8xx_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= intel_840_configure,
 	.fetch_size		= intel_8xx_fetch_size,
 	.cleanup		= intel_8xx_cleanup,
@@ -594,6 +599,7 @@ static const struct agp_bridge_driver intel_845_driver = {
 	.aperture_sizes		= intel_8xx_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= intel_845_configure,
 	.fetch_size		= intel_8xx_fetch_size,
 	.cleanup		= intel_8xx_cleanup,
@@ -620,6 +626,7 @@ static const struct agp_bridge_driver intel_850_driver = {
 	.aperture_sizes		= intel_8xx_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= intel_850_configure,
 	.fetch_size		= intel_8xx_fetch_size,
 	.cleanup		= intel_8xx_cleanup,
@@ -646,6 +653,7 @@ static const struct agp_bridge_driver intel_860_driver = {
 	.aperture_sizes		= intel_8xx_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= intel_860_configure,
 	.fetch_size		= intel_8xx_fetch_size,
 	.cleanup		= intel_8xx_cleanup,
@@ -672,6 +680,7 @@ static const struct agp_bridge_driver intel_7505_driver = {
 	.aperture_sizes		= intel_8xx_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= intel_7505_configure,
 	.fetch_size		= intel_8xx_fetch_size,
 	.cleanup		= intel_8xx_cleanup,

drivers/char/agp/nvidia-agp.c

@@ -310,6 +310,7 @@ static const struct agp_bridge_driver nvidia_driver = {
 	.aperture_sizes		= nvidia_generic_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 5,
+	.needs_scratch_page	= true,
 	.configure		= nvidia_configure,
 	.fetch_size		= nvidia_fetch_size,
 	.cleanup		= nvidia_cleanup,

drivers/char/agp/sis-agp.c

@@ -125,6 +125,7 @@ static struct agp_bridge_driver sis_driver = {
 	.aperture_sizes		= sis_generic_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 7,
+	.needs_scratch_page	= true,
 	.configure		= sis_configure,
 	.fetch_size		= sis_fetch_size,
 	.cleanup		= sis_cleanup,

drivers/char/agp/uninorth-agp.c

@@ -28,6 +28,7 @@
  */
 static int uninorth_rev;
 static int is_u3;
+static u32 scratch_value;
 
 #define DEFAULT_APERTURE_SIZE 256
 #define DEFAULT_APERTURE_STRING "256"
@@ -172,7 +173,7 @@ static int uninorth_insert_memory(struct agp_memory *mem, off_t pg_start, int ty
 
 	gp = (u32 *) &agp_bridge->gatt_table[pg_start];
 	for (i = 0; i < mem->page_count; ++i) {
-		if (gp[i]) {
+		if (gp[i] != scratch_value) {
 			dev_info(&agp_bridge->dev->dev,
 				 "uninorth_insert_memory: entry 0x%x occupied (%x)\n",
 				 i, gp[i]);
@@ -214,8 +215,9 @@ int uninorth_remove_memory(struct agp_memory *mem, off_t pg_start, int type)
 		return 0;
 
 	gp = (u32 *) &agp_bridge->gatt_table[pg_start];
-	for (i = 0; i < mem->page_count; ++i)
-		gp[i] = 0;
+	for (i = 0; i < mem->page_count; ++i) {
+		gp[i] = scratch_value;
+	}
 	mb();
 	uninorth_tlbflush(mem);
 
@@ -421,8 +423,13 @@ static int uninorth_create_gatt_table(struct agp_bridge_data *bridge)
 
 	bridge->gatt_bus_addr = virt_to_phys(table);
 
+	if (is_u3)
+		scratch_value = (page_to_phys(agp_bridge->scratch_page_page) >> PAGE_SHIFT) | 0x80000000UL;
+	else
+		scratch_value =	cpu_to_le32((page_to_phys(agp_bridge->scratch_page_page) & 0xFFFFF000UL) |
+				0x1UL);
 	for (i = 0; i < num_entries; i++)
-		bridge->gatt_table[i] = 0;
+		bridge->gatt_table[i] = scratch_value;
 
 	return 0;
 
@@ -519,6 +526,7 @@ const struct agp_bridge_driver uninorth_agp_driver = {
 	.agp_destroy_pages	= agp_generic_destroy_pages,
 	.agp_type_to_mask_type  = agp_generic_type_to_mask_type,
 	.cant_use_aperture	= true,
+	.needs_scratch_page	= true,
 };
 
 const struct agp_bridge_driver u3_agp_driver = {

drivers/char/agp/via-agp.c

@@ -175,6 +175,7 @@ static const struct agp_bridge_driver via_agp3_driver = {
 	.aperture_sizes		= agp3_generic_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 10,
+	.needs_scratch_page	= true,
 	.configure		= via_configure_agp3,
 	.fetch_size		= via_fetch_size_agp3,
 	.cleanup		= via_cleanup_agp3,
@@ -201,6 +202,7 @@ static const struct agp_bridge_driver via_driver = {
 	.aperture_sizes		= via_generic_sizes,
 	.size_type		= U8_APER_SIZE,
 	.num_aperture_sizes	= 9,
+	.needs_scratch_page	= true,
 	.configure		= via_configure,
 	.fetch_size		= via_fetch_size,
 	.cleanup		= via_cleanup,