ARM: tegra: enable GPU node by compatible value

In current Linux kernel Tegra DT files, 64-bit addresses are represented
in unit addresses as a pair of comma-separated 32-bit values. Apparently
this is no longer the correct representation for simple busses, and the
unit address should be represented as a single 64-bit value. If this is
changed in the DTs, arm/arm/mach-tegra/board2.c:ft_system_setup() will no
longer be able to find and enable the GPU node, since it looks up the node
by name.

Fix that function to enable nodes based on their compatible value rather
than their node name. This will work no matter what the node name is, i.e
for DTs both before and after any rename operation.

Cc: Thierry Reding <treding@nvidia.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>

arch/arm/include/asm/arch-tegra/gpu.h

@@ -26,7 +26,7 @@ int tegra_gpu_enable_node(void *blob, const char *gpupath);
 
 #else /* CONFIG_OF_LIBFDT */
 
-static inline int tegra_gpu_enable_node(void *blob, const char *gpupath)
+static inline int tegra_gpu_enable_node(void *blob, const char *compat)
 {
 	return 0;
 }

arch/arm/mach-tegra/board2.c

@@ -404,16 +404,22 @@ ulong board_get_usable_ram_top(ulong total_size)
  */
 int ft_system_setup(void *blob, bd_t *bd)
 {
-	const char *gpu_path =
-#if defined(CONFIG_TEGRA124) || defined(CONFIG_TEGRA210)
-		"/gpu@0,57000000";
-#else
-		NULL;
+	const char *gpu_compats[] = {
+#if defined(CONFIG_TEGRA124)
+		"nvidia,gk20a",
+#endif
+#if defined(CONFIG_TEGRA210)
+		"nvidia,gm20b",
 #endif
+	};
+	int i, ret;
 
 	/* Enable GPU node if GPU setup has been performed */
-	if (gpu_path != NULL)
-		return tegra_gpu_enable_node(blob, gpu_path);
+	for (i = 0; i < ARRAY_SIZE(gpu_compats); i++) {
+		ret = tegra_gpu_enable_node(blob, gpu_compats[i]);
+		if (ret)
+			return ret;
+	}
 
 	return 0;
 }

arch/arm/mach-tegra/gpu.c

@@ -33,16 +33,17 @@ void tegra_gpu_config(void)
 
 #if defined(CONFIG_OF_LIBFDT)
 
-int tegra_gpu_enable_node(void *blob, const char *gpupath)
+int tegra_gpu_enable_node(void *blob, const char *compat)
 {
 	int offset;
 
-	if (_configured) {
-		offset = fdt_path_offset(blob, gpupath);
-		if (offset > 0) {
-			fdt_status_okay(blob, offset);
-			debug("enabled GPU node %s\n", gpupath);
-		}
+	if (!_configured)
+		return 0;
+
+	offset = fdt_node_offset_by_compatible(blob, -1, compat);
+	while (offset != -FDT_ERR_NOTFOUND) {
+		fdt_status_okay(blob, offset);
+		offset = fdt_node_offset_by_compatible(blob, offset, compat);
 	}
 
 	return 0;