[igt-dev] [PATCH i-g-t v2 04/10] lib/igt_draw: Add pixel math for tile-4
Jeevan B
jeevan.b at intel.com
Wed Mar 2 14:39:17 UTC 2022
From: Matt Roper <matthew.d.roper at intel.com>
We need to implement the tile-4 math to convert x,y coordinates to
buffer offsets and vice versa for cases where we're using the CPU to
tile/detile rather than a GPU engine (e.g., the mmap_cpu and pwrite
subtests for kms_draw_crc).
The bspec description of tiling-4 is very confusing/misleading, but the
implementation here does match the tile-4 content generated by GPU
engines and recognized properly by the display controller.
Cc: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
Signed-off-by: Jeevan B <jeevan.b at intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
---
lib/igt_draw.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 111 insertions(+), 2 deletions(-)
diff --git a/lib/igt_draw.c b/lib/igt_draw.c
index 0ca43deb..d78ecdf0 100644
--- a/lib/igt_draw.c
+++ b/lib/igt_draw.c
@@ -226,6 +226,71 @@ static int linear_x_y_to_ytiled_pos(int x, int y, uint32_t stride, int swizzle,
return pos / pixel_size;
}
+#define OW_SIZE 16 /* in bytes */
+#define TILE_4_SUBTILE_SIZE 64 /* in bytes */
+#define TILE_4_WIDTH 128 /* in bytes */
+#define TILE_4_HEIGHT 32 /* in pixels */
+#define TILE_4_SUBTILE_WIDTH OW_SIZE /* in bytes */
+#define TILE_4_SUBTILE_HEIGHT 4 /* in pixels */
+
+/*
+ * Subtile remapping for tile 4. Note that map[a]==b implies map[b]==a
+ * so we can use the same table to tile and until.
+ */
+static const int tile4_subtile_map[] = {
+ 0, 1, 2, 3, 8, 9, 10, 11,
+ 4, 5, 6, 7, 12, 13, 14, 15,
+ 16, 17, 18, 19, 24, 25, 26, 27,
+ 20, 21, 22, 23, 28, 29, 30, 31,
+ 32, 33, 34, 35, 40, 41, 42, 43,
+ 36, 37, 38, 39, 44, 45, 46, 47,
+ 48, 49, 50, 51, 56, 57, 58, 59,
+ 52, 53, 54, 55, 60, 61, 62, 63
+};
+
+static int linear_x_y_to_4tiled_pos(int x, int y, uint32_t stride, int swizzle,
+ int bpp)
+{
+ int tile_base_pos;
+ int tile_x, tile_y;
+ int subtile_col, subtile_row, subtile_num, new_subtile_num;
+ int pixel_size = bpp / 8;
+ int byte_x = x * pixel_size;
+ int pos;
+
+ /* Modern platforms that have 4-tiling don't use old bit 6 swizzling */
+ igt_assert_eq(swizzle, I915_BIT_6_SWIZZLE_NONE);
+
+ /*
+ * Where does the 4k tile start (in bytes)? This is the same for Y and
+ * F so we can use the Y-tile algorithm to get to that point.
+ */
+ tile_base_pos = (y / TILE_4_HEIGHT) * stride * TILE_4_HEIGHT +
+ 4096 * (byte_x / TILE_4_WIDTH);
+
+ /* Find pixel within tile */
+ tile_x = (byte_x % TILE_4_WIDTH);
+ tile_y = y % TILE_4_HEIGHT;
+
+ /* And figure out the subtile within the 4k tile */
+ subtile_col = tile_x / TILE_4_SUBTILE_WIDTH;
+ subtile_row = tile_y / TILE_4_SUBTILE_HEIGHT;
+ subtile_num = subtile_row * 8 + subtile_col;
+
+ /* Swizzle the subtile number according to the bspec diagram */
+ new_subtile_num = tile4_subtile_map[subtile_num];
+
+ /* Calculate new position */
+ pos = tile_base_pos +
+ new_subtile_num * TILE_4_SUBTILE_SIZE +
+ (tile_y % TILE_4_SUBTILE_HEIGHT) * OW_SIZE +
+ tile_x % TILE_4_SUBTILE_WIDTH;
+ igt_assert(pos % pixel_size == 0);
+ pos /= pixel_size;
+
+ return pos;
+}
+
static void xtiled_pos_to_x_y_linear(int tiled_pos, uint32_t stride,
int swizzle, int bpp, int *x, int *y)
{
@@ -253,6 +318,44 @@ static void ytiled_pos_to_x_y_linear(int tiled_pos, uint32_t stride,
*x /= pixel_size;
}
+static void tile4_pos_to_x_y_linear(int tiled_pos, uint32_t stride,
+ int swizzle, int bpp, int *x, int *y)
+{
+ int pixel_size = bpp / 8;
+ int tiles_per_line = stride / TILE_4_WIDTH;
+ int tile_num, tile_offset, tile_row, tile_col;
+ int tile_origin_x, tile_origin_y;
+ int subtile_num, subtile_offset, subtile_row, subtile_col;
+ int subtile_origin_x, subtile_origin_y;
+ int oword_num, byte_num;
+
+ /* Modern platforms that have 4-tiling don't use old bit 6 swizzling */
+ igt_assert_eq(swizzle, I915_BIT_6_SWIZZLE_NONE);
+
+ /* Calculate the x,y of the start of the 4k tile */
+ tile_num = tiled_pos / 4096;
+ tile_row = tile_num / tiles_per_line;
+ tile_col = tile_num % tiles_per_line;
+ tile_origin_x = tile_col * TILE_4_WIDTH;
+ tile_origin_y = tile_row * TILE_4_HEIGHT;
+
+ /* Now calculate the x,y offset of the start of the subtile */
+ tile_offset = tiled_pos % 4096;
+ subtile_num = tile4_subtile_map[tile_offset / TILE_4_SUBTILE_SIZE];
+ subtile_row = subtile_num / 8;
+ subtile_col = subtile_num % 8;
+ subtile_origin_x = subtile_col * TILE_4_SUBTILE_WIDTH;
+ subtile_origin_y = subtile_row * TILE_4_SUBTILE_HEIGHT;
+
+ /* Next the oword and byte within the subtile */
+ subtile_offset = tiled_pos % TILE_4_SUBTILE_SIZE;
+ oword_num = subtile_offset / OW_SIZE;
+ byte_num = subtile_offset % OW_SIZE;
+
+ *x = (tile_origin_x + subtile_origin_x + byte_num) / pixel_size;
+ *y = tile_origin_y + subtile_origin_y + oword_num;
+}
+
static void set_pixel(void *_ptr, int index, uint32_t color, int bpp)
{
if (bpp == 16) {
@@ -318,10 +421,13 @@ static void draw_rect_ptr_tiled(void *ptr, uint32_t stride, uint32_t tiling,
swizzle, bpp);
break;
case I915_TILING_Y:
- case I915_TILING_4:
pos = linear_x_y_to_ytiled_pos(x, y, stride,
swizzle, bpp);
break;
+ case I915_TILING_4:
+ pos = linear_x_y_to_4tiled_pos(x, y, stride,
+ swizzle, bpp);
+ break;
default:
igt_assert(false);
}
@@ -470,10 +576,13 @@ static void draw_rect_pwrite_tiled(int fd, struct buf_data *buf,
swizzle, buf->bpp, &x, &y);
break;
case I915_TILING_Y:
- case I915_TILING_4:
ytiled_pos_to_x_y_linear(tiled_pos, buf->stride,
swizzle, buf->bpp, &x, &y);
break;
+ case I915_TILING_4:
+ tile4_pos_to_x_y_linear(tiled_pos, buf->stride,
+ swizzle, buf->bpp, &x, &y);
+ break;
default:
igt_assert(false);
}
--
2.17.1
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