drm/vc4: Add support for YUV planes.

This supports 420 and 422 subsampling with 2 or 3 planes, tested with
modetest.  It doesn't set up chroma subsampling position (which it
appears KMS doesn't deal with yet).

The LBM memory is overallocated in many cases, but apparently the docs
aren't quite correct and I'll probably need to look at the hardware
source to really figure it out.
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/vc4/vc4_regs.h

@@ -503,7 +503,12 @@ enum hvs_pixel_format {
 	HVS_PIXEL_FORMAT_RGB888 = 5,
 	HVS_PIXEL_FORMAT_RGBA6666 = 6,
 	/* 32bpp */
-	HVS_PIXEL_FORMAT_RGBA8888 = 7
+	HVS_PIXEL_FORMAT_RGBA8888 = 7,
+
+	HVS_PIXEL_FORMAT_YCBCR_YUV420_3PLANE = 8,
+	HVS_PIXEL_FORMAT_YCBCR_YUV420_2PLANE = 9,
+	HVS_PIXEL_FORMAT_YCBCR_YUV422_3PLANE = 10,
+	HVS_PIXEL_FORMAT_YCBCR_YUV422_2PLANE = 11,
 };
 
 /* Note: the LSB is the rightmost character shown.  Only valid for
@@ -585,6 +590,55 @@ enum hvs_pixel_format {
 #define SCALER_POS2_WIDTH_MASK			VC4_MASK(11, 0)
 #define SCALER_POS2_WIDTH_SHIFT			0
 
+/* Color Space Conversion words.  Some values are S2.8 signed
+ * integers, except that the 2 integer bits map as {0x0: 0, 0x1: 1,
+ * 0x2: 2, 0x3: -1}
+ */
+/* bottom 8 bits of S2.8 contribution of Cr to Blue */
+#define SCALER_CSC0_COEF_CR_BLU_MASK		VC4_MASK(31, 24)
+#define SCALER_CSC0_COEF_CR_BLU_SHIFT		24
+/* Signed offset to apply to Y before CSC. (Y' = Y + YY_OFS) */
+#define SCALER_CSC0_COEF_YY_OFS_MASK		VC4_MASK(23, 16)
+#define SCALER_CSC0_COEF_YY_OFS_SHIFT		16
+/* Signed offset to apply to CB before CSC (Cb' = Cb - 128 + CB_OFS). */
+#define SCALER_CSC0_COEF_CB_OFS_MASK		VC4_MASK(15, 8)
+#define SCALER_CSC0_COEF_CB_OFS_SHIFT		8
+/* Signed offset to apply to CB before CSC (Cr' = Cr - 128 + CR_OFS). */
+#define SCALER_CSC0_COEF_CR_OFS_MASK		VC4_MASK(7, 0)
+#define SCALER_CSC0_COEF_CR_OFS_SHIFT		0
+#define SCALER_CSC0_ITR_R_601_5			0x00f00000
+#define SCALER_CSC0_ITR_R_709_3			0x00f00000
+#define SCALER_CSC0_JPEG_JFIF			0x00000000
+
+/* S2.8 contribution of Cb to Green */
+#define SCALER_CSC1_COEF_CB_GRN_MASK		VC4_MASK(31, 22)
+#define SCALER_CSC1_COEF_CB_GRN_SHIFT		22
+/* S2.8 contribution of Cr to Green */
+#define SCALER_CSC1_COEF_CR_GRN_MASK		VC4_MASK(21, 12)
+#define SCALER_CSC1_COEF_CR_GRN_SHIFT		12
+/* S2.8 contribution of Y to all of RGB */
+#define SCALER_CSC1_COEF_YY_ALL_MASK		VC4_MASK(11, 2)
+#define SCALER_CSC1_COEF_YY_ALL_SHIFT		2
+/* top 2 bits of S2.8 contribution of Cr to Blue */
+#define SCALER_CSC1_COEF_CR_BLU_MASK		VC4_MASK(1, 0)
+#define SCALER_CSC1_COEF_CR_BLU_SHIFT		0
+#define SCALER_CSC1_ITR_R_601_5			0xe73304a8
+#define SCALER_CSC1_ITR_R_709_3			0xf2b784a8
+#define SCALER_CSC1_JPEG_JFIF			0xea34a400
+
+/* S2.8 contribution of Cb to Red */
+#define SCALER_CSC2_COEF_CB_RED_MASK		VC4_MASK(29, 20)
+#define SCALER_CSC2_COEF_CB_RED_SHIFT		20
+/* S2.8 contribution of Cr to Red */
+#define SCALER_CSC2_COEF_CR_RED_MASK		VC4_MASK(19, 10)
+#define SCALER_CSC2_COEF_CR_RED_SHIFT		10
+/* S2.8 contribution of Cb to Blue */
+#define SCALER_CSC2_COEF_CB_BLU_MASK		VC4_MASK(19, 10)
+#define SCALER_CSC2_COEF_CB_BLU_SHIFT		10
+#define SCALER_CSC2_ITR_R_601_5			0x00066204
+#define SCALER_CSC2_ITR_R_709_3			0x00072a1c
+#define SCALER_CSC2_JPEG_JFIF			0x000599c5
+
 #define SCALER_TPZ0_VERT_RECALC			BIT(31)
 #define SCALER_TPZ0_SCALE_MASK			VC4_MASK(28, 8)
 #define SCALER_TPZ0_SCALE_SHIFT			8