[PATCH] drm: add FOURCC formats for compute dma_buf interop.

[Gwenole Beauchesne]

This is a follow-up to:
http://lists.freedesktop.org/archives/mesa-dev/2014-March/055742.html

Add formats meant to convey a "compute" dimension when a DRM fourcc
format is needed for dma_buf interop (EGL, OpenCL).

Intended FOURCC format: ('T',<num_elements>,<type>,<size_element>).
- <num_elements>: number of elements in the tuple. Range: [0..3].
- <type>: type of each element. Values: {'_','I','U','F'},
  respectively for normalized to [0..1] range, signed integers,
  unsigned integers, floating-point.
- <size_element>: size of the element. Values: {1, 2, 4, 8}.

All entities are represented in native-endian byte-order in memory.
For example, 'T2F4' format would represent the (float, float) tuple
where elements are stored in little-endian byte-order on x86.

Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne at intel.com>
---
 include/drm/drm_fourcc.h |   78 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)

diff --git a/include/drm/drm_fourcc.h b/include/drm/drm_fourcc.h
index 85facb0..26a2ca8 100644
--- a/include/drm/drm_fourcc.h
+++ b/include/drm/drm_fourcc.h
@@ -127,4 +127,82 @@
 #define DRM_FORMAT_YUV444	fourcc_code('Y', 'U', '2', '4') /* non-subsampled Cb (1) and Cr (2) planes */
 #define DRM_FORMAT_YVU444	fourcc_code('Y', 'V', '2', '4') /* non-subsampled Cr (1) and Cb (2) planes */
 
+/**
+ * \defgroup api_drm_tuples Compute formats (tuples)
+ *
+ * The following formats are not meant for display. Rather, they are
+ * meant to convey a "compute" dimension when a DRM fourcc format is
+ * needed for dma_buf interop (EGL, OpenCL).
+ *
+ * Intended FOURCC format: ('T',<num_elements>,<type>,<size_element>).
+ * - <num_elements>: number of elements in the tuple. Range: [0..3].
+ * - <type>: type of each element. Values: {'_','I','U','F'},
+ *   respectively for normalized to [0..1] range, signed integers,
+ *   unsigned integers, floating-point.
+ * - <size_element>: size of the element. Values: {1, 2, 4, 8}.
+ *
+ * All entities are represented in native-endian byte-order in memory.
+ * For example, 'T2F4' format would represent the (float, float) tuple
+ * where elements are stored in little-endian byte-order on x86.
+ *
+ * @{
+ */
+
+/** Type of a tuple element */
+enum {
+    DRM_FORMAT_TUPLE_TYPE_UNORM	= '_', /**< Unsigned integer value normalized to [0..1] range */
+    DRM_FORMAT_TUPLE_TYPE_SINT	= 'I', /**< Signed integer value */
+    DRM_FORMAT_TUPLE_TYPE_UINT	= 'U', /**< Unsigned integer value */
+    DRM_FORMAT_TUPLE_TYPE_FLOAT	= 'F', /**< Floating-point value */
+};
+
+/** Generates a FOURCC value for a tuple */
+#define DRM_FORMAT_TUPLE(num_elements, type, size) \
+    fourcc_code('T', '0'+(num_elements), DRM_FORMAT_TUPLE_TYPE_##type, '0'+(size))
+
+/** @name Unsigned integers normalized to [0..1] range */
+/**@{*/
+#define DRM_FORMAT_T1_1		DRM_FORMAT_TUPLE(1, UNORM, 1) /** (X), 8-bit integers normalized to [0..1] range */
+#define DRM_FORMAT_T2_1		DRM_FORMAT_TUPLE(2, UNORM, 1) /** (X, Y), 8-bit integers normalized to [0..1] range */
+#define DRM_FORMAT_T4_1		DRM_FORMAT_TUPLE(4, UNORM, 1) /** (X, Y, Z, W), 8-bit integers normalized to [0..1] range */
+#define DRM_FORMAT_T1_2		DRM_FORMAT_TUPLE(1, UNORM, 2) /** (X), 16-bit integers normalized to [0..1] range */
+#define DRM_FORMAT_T2_2		DRM_FORMAT_TUPLE(2, UNORM, 2) /** (X, Y), 16-bit integers normalized to [0..1] range */
+#define DRM_FORMAT_T4_2		DRM_FORMAT_TUPLE(4, UNORM, 2) /** (X, Y, Z, W), 16-bit integers normalized to [0..1] range */
+/**@}*/
+
+/** @name Signed integer values */
+/**@{*/
+#define DRM_FORMAT_T1I1		DRM_FORMAT_TUPLE(1, SINT, 1) /** (X), 8-bit signed integer */
+#define DRM_FORMAT_T2I1		DRM_FORMAT_TUPLE(2, SINT, 1) /** (X, Y), 8-bit signed integer */
+#define DRM_FORMAT_T4I1		DRM_FORMAT_TUPLE(4, SINT, 1) /** (X, Y, Z, W), 8-bit signed integer */
+#define DRM_FORMAT_T1I2		DRM_FORMAT_TUPLE(1, SINT, 2) /** (X), 16-bit signed integer */
+#define DRM_FORMAT_T2I2		DRM_FORMAT_TUPLE(2, SINT, 2) /** (X, Y), 16-bit signed integer */
+#define DRM_FORMAT_T4I2		DRM_FORMAT_TUPLE(4, SINT, 2) /** (X, Y, Z, W), 16-bit signed integer */
+#define DRM_FORMAT_T1I4		DRM_FORMAT_TUPLE(1, SINT, 4) /** (X), 32-bit signed integer */
+#define DRM_FORMAT_T2I4		DRM_FORMAT_TUPLE(2, SINT, 4) /** (X, Y), 32-bit signed integer */
+#define DRM_FORMAT_T4I4		DRM_FORMAT_TUPLE(4, SINT, 4) /** (X, Y, Z, W), 32-bit signed integer */
+/**@}*/
+
+/** @name Unsigned integer values */
+/**@{*/
+#define DRM_FORMAT_T1U1		DRM_FORMAT_TUPLE(1, UINT, 1) /** (X), 8-bit unsigned integer */
+#define DRM_FORMAT_T2U1		DRM_FORMAT_TUPLE(2, UINT, 1) /** (X, Y), 8-bit unsigned integer */
+#define DRM_FORMAT_T4U1		DRM_FORMAT_TUPLE(4, UINT, 1) /** (X, Y, Z, W), 8-bit unsigned integer */
+#define DRM_FORMAT_T1U2		DRM_FORMAT_TUPLE(1, UINT, 2) /** (X), 16-bit unsigned integer */
+#define DRM_FORMAT_T2U2		DRM_FORMAT_TUPLE(2, UINT, 2) /** (X, Y), 16-bit unsigned integer */
+#define DRM_FORMAT_T4U2		DRM_FORMAT_TUPLE(4, UINT, 2) /** (X, Y, Z, W), 16-bit unsigned integer */
+#define DRM_FORMAT_T1U4		DRM_FORMAT_TUPLE(1, UINT, 4) /** (X), 32-bit unsigned integer */
+#define DRM_FORMAT_T2U4		DRM_FORMAT_TUPLE(2, UINT, 4) /** (X, Y), 32-bit unsigned integer */
+#define DRM_FORMAT_T4U4		DRM_FORMAT_TUPLE(4, UINT, 4) /** (X, Y, Z, W), 32-bit unsigned integer */
+/**@}*/
+
+/** @name Floating-point values */
+/**@{*/
+#define DRM_FORMAT_T1F4		DRM_FORMAT_TUPLE(1, FLOAT, 4) /** (X), 32-bit floating-point */
+#define DRM_FORMAT_T2F4		DRM_FORMAT_TUPLE(2, FLOAT, 4) /** (X, Y), 32-bit floating-point */
+#define DRM_FORMAT_T4F4		DRM_FORMAT_TUPLE(4, FLOAT, 4) /** (X, Y, Z, W), 32-bit floating-point */
+/**@}*/
+
+/**@}*/
+
 #endif /* DRM_FOURCC_H */
-- 
1.7.9.5