[PATCH 2/2] drm/tegra: Sanitize format modifiers

[Thierry Reding]

From: Thierry Reding <treding at nvidia.com>

The existing format modifier definitions were merged prematurely, and
recent work has unveiled that the definitions are suboptimal in several
ways:

  - The format specifiers, except for one, are not Tegra specific, but
    the names don't reflect that.
  - The number space is split into two, reserving 32 bits for some
    "parameter" which most of the modifiers are not going to have.
  - Symbolic names for the modifiers are not using the standard
    DRM_FORMAT_MOD_* prefix, which makes them awkward to use.
  - The vendor prefix NV is somewhat ambiguous.

Fortunately, nobody's started using these modifiers, so we can still fix
the above issues. Do so by using the standard prefix. Also, remove TEGRA
from the name of those modifiers that exist on NVIDIA GPUs as well. In
case of the block linear modifiers, make the "parameter" smaller (4
bits, though only 6 values are valid) and don't let that leak into any
of the other modifiers.

Finally, also use the more canonical NVIDIA instead of the ambiguous NV
prefix.

Signed-off-by: Thierry Reding <treding at nvidia.com>
---
 drivers/gpu/drm/tegra/fb.c    | 35 +++++++++++++++++++++++++++++------
 include/uapi/drm/drm_fourcc.h | 36 +++++++++++++++++++-----------------
 2 files changed, 48 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/tegra/fb.c b/drivers/gpu/drm/tegra/fb.c
index 80540c1c66dc..406e895d82cc 100644
--- a/drivers/gpu/drm/tegra/fb.c
+++ b/drivers/gpu/drm/tegra/fb.c
@@ -54,17 +54,40 @@ int tegra_fb_get_tiling(struct drm_framebuffer *framebuffer,
 	struct tegra_fb *fb = to_tegra_fb(framebuffer);
 	uint64_t modifier = fb->base.modifier;
 
-	switch (fourcc_mod_tegra_mod(modifier)) {
-	case NV_FORMAT_MOD_TEGRA_TILED:
+	switch (modifier) {
+	case DRM_FORMAT_MOD_NVIDIA_TEGRA_TILED:
 		tiling->mode = TEGRA_BO_TILING_MODE_TILED;
 		tiling->value = 0;
 		break;
 
-	case NV_FORMAT_MOD_TEGRA_16BX2_BLOCK(0):
+	case DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(0):
 		tiling->mode = TEGRA_BO_TILING_MODE_BLOCK;
-		tiling->value = fourcc_mod_tegra_param(modifier);
-		if (tiling->value > 5)
-			return -EINVAL;
+		tiling->value = 0;
+		break;
+
+	case DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(1):
+		tiling->mode = TEGRA_BO_TILING_MODE_BLOCK;
+		tiling->value = 1;
+		break;
+
+	case DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(2):
+		tiling->mode = TEGRA_BO_TILING_MODE_BLOCK;
+		tiling->value = 2;
+		break;
+
+	case DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(3):
+		tiling->mode = TEGRA_BO_TILING_MODE_BLOCK;
+		tiling->value = 3;
+		break;
+
+	case DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(4):
+		tiling->mode = TEGRA_BO_TILING_MODE_BLOCK;
+		tiling->value = 4;
+		break;
+
+	case DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(5):
+		tiling->mode = TEGRA_BO_TILING_MODE_BLOCK;
+		tiling->value = 5;
 		break;
 
 	default:
diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
index a76ed8f9e383..e04613d30a13 100644
--- a/include/uapi/drm/drm_fourcc.h
+++ b/include/uapi/drm/drm_fourcc.h
@@ -178,7 +178,7 @@ extern "C" {
 #define DRM_FORMAT_MOD_VENDOR_NONE    0
 #define DRM_FORMAT_MOD_VENDOR_INTEL   0x01
 #define DRM_FORMAT_MOD_VENDOR_AMD     0x02
-#define DRM_FORMAT_MOD_VENDOR_NV      0x03
+#define DRM_FORMAT_MOD_VENDOR_NVIDIA  0x03
 #define DRM_FORMAT_MOD_VENDOR_SAMSUNG 0x04
 #define DRM_FORMAT_MOD_VENDOR_QCOM    0x05
 #define DRM_FORMAT_MOD_VENDOR_VIVANTE 0x06
@@ -338,29 +338,17 @@ extern "C" {
  */
 #define DRM_FORMAT_MOD_VIVANTE_SPLIT_SUPER_TILED fourcc_mod_code(VIVANTE, 4)
 
-/* NVIDIA Tegra frame buffer modifiers */
-
-/*
- * Some modifiers take parameters, for example the number of vertical GOBs in
- * a block. Reserve the lower 32 bits for parameters
- */
-#define __fourcc_mod_tegra_mode_shift 32
-#define fourcc_mod_tegra_code(val, params) \
-	fourcc_mod_code(NV, ((((__u64)val) << __fourcc_mod_tegra_mode_shift) | params))
-#define fourcc_mod_tegra_mod(m) \
-	(m & ~((1ULL << __fourcc_mod_tegra_mode_shift) - 1))
-#define fourcc_mod_tegra_param(m) \
-	(m & ((1ULL << __fourcc_mod_tegra_mode_shift) - 1))
+/* NVIDIA frame buffer modifiers */
 
 /*
  * Tegra Tiled Layout, used by Tegra 2, 3 and 4.
  *
  * Pixels are arranged in simple tiles of 16 x 16 bytes.
  */
-#define NV_FORMAT_MOD_TEGRA_TILED fourcc_mod_tegra_code(1, 0)
+#define DRM_FORMAT_MOD_NVIDIA_TEGRA_TILED fourcc_mod_code(NVIDIA, 1)
 
 /*
- * Tegra 16Bx2 Block Linear layout, used by TK1/TX1
+ * 16Bx2 Block Linear layout, used by desktop GPUs, and Tegra K1 and later
  *
  * Pixels are arranged in 64x8 Groups Of Bytes (GOBs). GOBs are then stacked
  * vertically by a power of 2 (1 to 32 GOBs) to form a block.
@@ -380,7 +368,21 @@ extern "C" {
  * Chapter 20 "Pixel Memory Formats" of the Tegra X1 TRM describes this format
  * in full detail.
  */
-#define NV_FORMAT_MOD_TEGRA_16BX2_BLOCK(v) fourcc_mod_tegra_code(2, v)
+#define DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(v) \
+	fourcc_mod_code(NVIDIA, 0x10 | ((v) & 0xf))
+
+#define DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK_ONE_GOB \
+	fourcc_mod_code(NVIDIA, 0x10)
+#define DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK_TWO_GOB \
+	fourcc_mod_code(NVIDIA, 0x11)
+#define DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK_FOUR_GOB \
+	fourcc_mod_code(NVIDIA, 0x12)
+#define DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK_EIGHT_GOB \
+	fourcc_mod_code(NVIDIA, 0x13)
+#define DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK_SIXTEEN_GOB \
+	fourcc_mod_code(NVIDIA, 0x14)
+#define DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK_THIRTYTWO_GOB \
+	fourcc_mod_code(NVIDIA, 0x15)
 
 /*
  * Broadcom VC4 "T" format
-- 
2.15.0