[PATCH 1/2] intel_gtt: Harden against changes to kernel mappings of the GTT

[chris at chris-wilson.co.uk (Chris Wilson)]

Rather than use the common mmio segment which will be in future
restricted to just the registers and so exclude the GTT portion on all
architectures, explicitly mmap the GTT ourselves. Repeat this mmapping
with a couple of flags until we matching the existing kernel mapping.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 tools/intel_gtt.c |   46 ++++++++++++++++++++++++++++++----------------
 1 file changed, 30 insertions(+), 16 deletions(-)

diff --git a/tools/intel_gtt.c b/tools/intel_gtt.c
index c246fda..05d36d7 100644
--- a/tools/intel_gtt.c
+++ b/tools/intel_gtt.c
@@ -45,33 +45,47 @@ int main(int argc, char **argv)
 	int start, aper_size;
 	unsigned char *gtt;
 	uint32_t devid;
+	int flag[] = {
+		PCI_DEV_MAP_FLAG_WRITE_COMBINE,
+		PCI_DEV_MAP_FLAG_WRITABLE,
+		0
+	}, f;
 
 	pci_dev = intel_get_pci_device();
 	devid = pci_dev->device_id;
-	intel_get_mmio(pci_dev);
 
 	if (IS_GEN2(devid)) {
 		printf("Unsupported chipset for gtt dumper\n");
 		exit(1);
 	}
 
-	if (IS_G4X(devid) || IS_GEN5(devid))
-		gtt = ((unsigned char *)mmio + MB(2));
-	else if (IS_965(devid))
-		gtt = ((unsigned char *)mmio + KB(512));
-	else {
-		/* 915/945 chips has GTT range in bar 3 */
-		int err;
-		err = pci_device_map_range(pci_dev,
-					   pci_dev->regions[3].base_addr,
-					   pci_dev->regions[3].size,
-					   PCI_DEV_MAP_FLAG_WRITABLE,
-					   (void **)&gtt);
-		if (err != 0) {
-			fprintf(stderr, "mapping GTT bar failed\n");
-			exit(1);
+	for (f = 0; flag[f] != 0; f++) {
+		if (IS_GEN3(devid)) {
+			/* 915/945 chips has GTT range in bar 3 */
+			if (pci_device_map_range(pci_dev,
+						 pci_dev->regions[3].base_addr,
+						 pci_dev->regions[3].size,
+						 flag[f],
+						 (void **)&gtt) == 0)
+				break;
+		} else {
+			int offset;
+			if (IS_G4X(devid) || IS_GEN5(devid))
+				offset = MB(2);
+			else
+				offset = KB(512);
+			if (pci_device_map_range(pci_dev,
+						 pci_dev->regions[0].base_addr + offset,
+						 offset,
+						 flag[f],
+						 (void **)&gtt) == 0)
+				break;
 		}
 	}
+	if (flag[f] == 0) {
+		printf("Failed to map gtt\n");
+		exit(1);
+	}
 
 	aper_size = pci_dev->regions[2].size;
 
-- 
1.7.10.4