drm/radeon/kms: add 3DC compression support

There are 2 formats:
ATI1N: 64 bits per 4x4 block, one-channel format
ATI2N: 128 bits per 4x4 block, two-channel format

Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/r300.c

@@ -887,6 +887,14 @@ static int r300_packet0_check(struct radeon_cs_parser *p,
 			track->textures[i].cpp = 1;
 			track->textures[i].compress_format = R100_TRACK_COMP_DXT1;
 			break;
+		case R300_TX_FORMAT_ATI2N:
+			if (p->rdev->family < CHIP_R420) {
+				DRM_ERROR("Invalid texture format %u\n",
+					  (idx_value & 0x1F));
+				return -EINVAL;
+			}
+			/* The same rules apply as for DXT3/5. */
+			/* Pass through. */
 		case R300_TX_FORMAT_DXT3:
 		case R300_TX_FORMAT_DXT5:
 			track->textures[i].cpp = 1;
@@ -951,6 +959,16 @@ static int r300_packet0_check(struct radeon_cs_parser *p,
 			track->textures[i].width_11 = tmp;
 			tmp = ((idx_value >> 16) & 1) << 11;
 			track->textures[i].height_11 = tmp;
+
+			/* ATI1N */
+			if (idx_value & (1 << 14)) {
+				/* The same rules apply as for DXT1. */
+				track->textures[i].compress_format =
+					R100_TRACK_COMP_DXT1;
+			}
+		} else if (idx_value & (1 << 14)) {
+			DRM_ERROR("Forbidden bit TXFORMAT_MSB\n");
+			return -EINVAL;
 		}
 		break;
 	case 0x4480:

drivers/gpu/drm/radeon/r300_reg.h

@@ -900,6 +900,7 @@
 #	define R300_TX_FORMAT_FL_I32		    0x1B
 #	define R300_TX_FORMAT_FL_I32A32		    0x1C
 #	define R300_TX_FORMAT_FL_R32G32B32A32	    0x1D
+#	define R300_TX_FORMAT_ATI2N		    0x1F
 	/* alpha modes, convenience mostly */
 	/* if you have alpha, pick constant appropriate to the
 	   number of channels (1 for I8, 2 for I8A8, 4 for R8G8B8A8, etc */