From: Eric Anholt eric@anholt.net
X/Y positioning of T-format buffers is quite tricky and the current implementation was failing to position a plane using this format correctly when the X, Y or both X and Y offsets were negative.
Signed-off-by: Eric Anholt eric@anholt.net Signed-off-by: Boris Brezillon boris.brezillon@bootlin.com --- Hi Eric,
I kept the SoB and authorship since you're the original author, but I also significantly reworked the code, so I'd be more confident if you could have a close look at this code.
It's been tested with a modified modetest (one that supports generating T-format buffers) and it seems to work fine with any kind of negative X/Y offset (both when starting on an even or an odd tile row).
Also, I intentionally did not add a Fixes and Cc-stable to this commit because it depends on a rework we've done in vc4_plane_setup_clipping_and_scaling() which cannot be easily backported. What I could do though is add a patch that rejects all negative crtc_{x,y}.
Regards,
Boris --- drivers/gpu/drm/vc4/vc4_plane.c | 51 +++++++++++++++++++++++++++++++++++------ 1 file changed, 44 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c index 2b8ba1c412be..ade47c3f65d1 100644 --- a/drivers/gpu/drm/vc4/vc4_plane.c +++ b/drivers/gpu/drm/vc4/vc4_plane.c @@ -539,22 +539,59 @@ static int vc4_plane_mode_set(struct drm_plane *plane, (i ? h_subsample : 1) * fb->format->cpp[i]; } + break;
case DRM_FORMAT_MOD_BROADCOM_VC4_T_TILED: { - /* For T-tiled, the FB pitch is "how many bytes from - * one row to the next, such that pitch * tile_h == - * tile_size * tiles_per_row." - */ u32 tile_size_shift = 12; /* T tiles are 4kb */ + /* Whole-tile offsets, mostly for setting the pitch. */ + u32 tile_w_shift = fb->format->cpp[0] == 2 ? 6 : 5; u32 tile_h_shift = 5; /* 16 and 32bpp are 32 pixels high */ + u32 tile_w_mask = (1 << tile_w_shift) - 1; + /* The height mask on 32-bit-per-pixel tiles is 63, i.e. 2 + * times the height (in pixels) of a 4k tile. I just assumed + * this is also true for other RGB formats, but maybe it's not. + */ + u32 tile_h_mask = (2 << tile_h_shift) - 1; + /* For T-tiled, the FB pitch is "how many bytes from one row to + * the next, such that + * + * pitch * tile_h == tile_size * tiles_per_row + */ u32 tiles_w = fb->pitches[0] >> (tile_size_shift - tile_h_shift); + u32 tiles_l = src_x >> tile_w_shift; + u32 tiles_r = tiles_w - tiles_l; + u32 tiles_t = src_y >> tile_h_shift; + /* Intra-tile offsets, which modify the base address (the + * SCALER_PITCH0_TILE_Y_OFFSET tells HVS how to walk from that + * base address). + */ + u32 tile_y = (src_y >> 4) & 1; + u32 subtile_y = (src_y >> 2) & 3; + u32 utile_y = src_y & 3; + u32 x_off = src_x & tile_w_mask; + u32 y_off = src_y & tile_h_mask;
tiling = SCALER_CTL0_TILING_256B_OR_T; + pitch0 = (VC4_SET_FIELD(x_off, SCALER_PITCH0_SINK_PIX) | + VC4_SET_FIELD(y_off, SCALER_PITCH0_TILE_Y_OFFSET) | + VC4_SET_FIELD(tiles_l, SCALER_PITCH0_TILE_WIDTH_L) | + VC4_SET_FIELD(tiles_r, SCALER_PITCH0_TILE_WIDTH_R)); + vc4_state->offsets[0] += tiles_t * (tiles_w << tile_size_shift); + vc4_state->offsets[0] += subtile_y << 8; + vc4_state->offsets[0] += utile_y << 4; + + /* Rows of tiles alternate left-to-right and right-to-left. */ + if (tiles_t & 1) { + pitch0 |= SCALER_PITCH0_TILE_INITIAL_LINE_DIR; + vc4_state->offsets[0] += (tiles_w - tiles_l) << + tile_size_shift; + vc4_state->offsets[0] -= (1 + !tile_y) << 10; + } else { + vc4_state->offsets[0] += tiles_l << tile_size_shift; + vc4_state->offsets[0] += tile_y << 10; + }
- pitch0 = (VC4_SET_FIELD(0, SCALER_PITCH0_TILE_Y_OFFSET) | - VC4_SET_FIELD(0, SCALER_PITCH0_TILE_WIDTH_L) | - VC4_SET_FIELD(tiles_w, SCALER_PITCH0_TILE_WIDTH_R)); break; }