drm/radeon/kms: setup mc chremap properly on r7xx/evergreen

Should improve performance slightly and possibly fix some
issues.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index 4dfead8..24ebd08 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/drivers/gpu/drm/radeon/rv770.c
@@ -489,6 +489,49 @@
 	return backend_map;
 }
 
+static void rv770_program_channel_remap(struct radeon_device *rdev)
+{
+	u32 tcp_chan_steer, mc_shared_chremap, tmp;
+	bool force_no_swizzle;
+
+	switch (rdev->family) {
+	case CHIP_RV770:
+	case CHIP_RV730:
+		force_no_swizzle = false;
+		break;
+	case CHIP_RV710:
+	case CHIP_RV740:
+	default:
+		force_no_swizzle = true;
+		break;
+	}
+
+	tmp = RREG32(MC_SHARED_CHMAP);
+	switch ((tmp & NOOFCHAN_MASK) >> NOOFCHAN_SHIFT) {
+	case 0:
+	case 1:
+	default:
+		/* default mapping */
+		mc_shared_chremap = 0x00fac688;
+		break;
+	case 2:
+	case 3:
+		if (force_no_swizzle)
+			mc_shared_chremap = 0x00fac688;
+		else
+			mc_shared_chremap = 0x00bbc298;
+		break;
+	}
+
+	if (rdev->family == CHIP_RV740)
+		tcp_chan_steer = 0x00ef2a60;
+	else
+		tcp_chan_steer = 0x00fac688;
+
+	WREG32(TCP_CHAN_STEER, tcp_chan_steer);
+	WREG32(MC_SHARED_CHREMAP, mc_shared_chremap);
+}
+
 static void rv770_gpu_init(struct radeon_device *rdev)
 {
 	int i, j, num_qd_pipes;
@@ -688,6 +731,8 @@
 	WREG32(DCP_TILING_CONFIG, (gb_tiling_config & 0xffff));
 	WREG32(HDP_TILING_CONFIG, (gb_tiling_config & 0xffff));
 
+	rv770_program_channel_remap(rdev);
+
 	WREG32(CC_RB_BACKEND_DISABLE,      cc_rb_backend_disable);
 	WREG32(CC_GC_SHADER_PIPE_CONFIG,   cc_gc_shader_pipe_config);
 	WREG32(GC_USER_SHADER_PIPE_CONFIG, cc_gc_shader_pipe_config);