Re: [igt-dev] [PATCH i-g-t 6/9] lib/igt_vc4: Add helpers for converting linear to T-tiled XRGB buffers

Paul Kocialkowski
2018-12-07T07:38:34Z

Hi,

On Thu, 2018-12-06 at 16:51 -0500, Lyude Paul wrote:
> One small nitpick
>
> On Thu, 2018-12-06 at 15:11 +0100, Paul Kocialkowski wrote:
> > In order to integrate testing of T-tiled buffers, the easiest path is to
> > generate patterns (with the already-existing functions) in linear
> > buffers and convert them to T-tiled subsequently.
> >
> > Add helpers to do that conversion, with a first helper that returns the
> > memory offset for a given position in a T-tiled buffer and a second
> > helper that uses it for converting between framebuffers.
> >
> > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > ---
> > lib/igt_vc4.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++
> > lib/igt_vc4.h | 4 +++
> > 2 files changed, 100 insertions(+)
> >
> > diff --git a/lib/igt_vc4.c b/lib/igt_vc4.c
> > index 16dfe67a..0b5124f3 100644
> > --- a/lib/igt_vc4.c
> > +++ b/lib/igt_vc4.c
> > @@ -34,6 +34,7 @@
> > #include "drmtest.h"
> > #include "igt_aux.h"
> > #include "igt_core.h"
> > +#include "igt_fb.h"
> > #include "igt_vc4.h"
> > #include "ioctl_wrappers.h"
> > #include "intel_reg.h"
> > @@ -176,3 +177,98 @@ bool igt_vc4_purgeable_bo(int fd, int handle, bool
> > purgeable)
> >
> > return arg.retained;
> > }
> > +
> > +unsigned int igt_vc4_fb_t_tiled_convert(struct igt_fb *dst, struct igt_fb
> > *src)
> > +{
> > + unsigned int fb_id;
> > + unsigned int i, j;
> > + uint32_t *src_buf;
> > + uint32_t *dst_buf;
> > + size_t offset;
> > +
> > + igt_assert(src->drm_format == DRM_FORMAT_XRGB8888);
> > +
> > + fb_id = igt_create_fb(src->fd, src->width, src->height, src-
> > > drm_format,
> > + DRM_FORMAT_MOD_BROADCOM_VC4_T_TILED, dst);
> > + igt_assert(fb_id > 0);
> > +
> > + src_buf = igt_fb_map_buffer(src->fd, src);
> > + igt_assert(src_buf);
> > +
> > + dst_buf = igt_fb_map_buffer(dst->fd, dst);
> > + igt_assert(dst_buf);
> > +
> > + for (i = 0; i < src->height; i++) {
> > + for (j = 0; j < src->width; j++) {
> > + offset = igt_vc4_t_tiled_offset(src->width, src-
> > > height,
> > + src->drm_format, j, i)
> > / 4;
> > + *(dst_buf + offset) = *(src_buf +
> > + src->strides[0] / 4 * i + j);
> > + }
> > + }
> > +
> > + igt_fb_unmap_buffer(src, src_buf);
> > + igt_fb_unmap_buffer(dst, dst_buf);
> > +
> > + return fb_id;
> > +}
> > +
> > +size_t igt_vc4_t_tiled_offset(size_t width, size_t height, size_t format,
> > + size_t x, size_t y)
> > +{
> > + size_t t1k_map_even[4] = { 0, 3, 1, 2 };
> > + size_t t1k_map_odd[4] = { 2, 1, 3, 0 };
> No need to specify the array size here, t1k_map_even[] and t1k_map_odd[]
> should be fine. Also, these look like they probably should be const.

Definitely, I will make these changes in v2!

Cheers,

Paul

> > + size_t offset = 0;
> > + size_t t4k_w, t4k_x, t4k_y;
> > + size_t t1k_x, t1k_y;
> > + size_t t64b_x, t64b_y;
> > + size_t pix_x, pix_y;
> > + unsigned int index;
> > +
> > + igt_assert(format == DRM_FORMAT_XRGB8888);
> > +
> > + /* Width in number of 4K tiles. */
> > + t4k_w = ALIGN(width, 32) / 32;
> > +
> > + /* X and y coordinates in number of 4K tiles (32x32). */
> > + t4k_x = x / 32;
> > + t4k_y = y / 32;
> > +
> > + /* Increase offset to the beginning of the corresponding 4K tile. */
> > + offset += t4k_y * t4k_w * 32 * 32;
> > +
> > + /* X and Y coordinates in number of 1K tiles (16x16) within the 4K
> > tile. */
> > + t1k_x = (x % 32) / 16;
> > + t1k_y = (y % 32) / 16;
> > +
> > + index = 2 * t1k_y + t1k_x;
> > +
> > + if (t4k_y % 2) {
> > + /* Odd rows start from the right. */
> > + offset += (t4k_w - t4k_x - 1) * 32 * 32;
> > + offset += t1k_map_odd[index] * 16 * 16;
> > + } else {
> > + /* Even rows start from the left. */
> > + offset += t4k_x * 32 * 32;
> > + offset += t1k_map_even[index] * 16 * 16;
> > + }
> > +
> > + /* X and Y coordinates in number of 64 byte tiles (4x4) within the 1K
> > tile. */
> > + t64b_x = (x % 16) / 4;
> > + t64b_y = (y % 16) / 4;
> > +
> > + /* Increase offset to the beginning of the corresponding 64 byte tile.
> > */
> > + offset += t64b_y * 4 * 4 * 4 + t64b_x * 4 * 4;
> > +
> > + /* X and Y coordinates in number of pixels within the 64 byte tile. */
> > + pix_x = x % 4;
> > + pix_y = y % 4;
> > +
> > + /* Increase offset to the correct pixel. */
> > + offset += pix_y * 4 + pix_x;
> > +
> > + /* Multiply by the number of bytes per pixel for the format. */
> > + offset *= 4;
> > +
> > + return offset;
> > +}
> > diff --git a/lib/igt_vc4.h b/lib/igt_vc4.h
> > index ebc8a388..ab44f771 100644
> > --- a/lib/igt_vc4.h
> > +++ b/lib/igt_vc4.h
> > @@ -33,4 +33,8 @@ bool igt_vc4_purgeable_bo(int fd, int handle, bool
> > purgeable);
> > void igt_vc4_set_tiling(int fd, uint32_t handle, uint64_t modifier);
> > uint64_t igt_vc4_get_tiling(int fd, uint32_t handle);
> >
> > +unsigned int igt_vc4_fb_t_tiled_convert(struct igt_fb *dst, struct igt_fb
> > *src);
> > +size_t igt_vc4_t_tiled_offset(size_t width, size_t height, size_t format,
> > + size_t x, size_t y);
> > +
> > #endif /* IGT_VC4_H */
--
Paul Kocialkowski, Bootlin (formerly Free Electrons)
Embedded Linux and kernel engineering