[PATCH v2 4/5] drm: Add support for handling linear tile formats
Alexandru-Cosmin Gheorghe
Alexandru-Cosmin.Gheorghe at arm.com
Thu Aug 23 17:43:40 UTC 2018
On Wed, Aug 22, 2018 at 10:18:51PM +0200, Daniel Vetter wrote:
> On Tue, Aug 21, 2018 at 07:30:03PM +0100, Alexandru Gheorghe wrote:
> > The previous patch added tile_w and tile_h, which represent the
> > horizontal and vertical sizes of a tile.
> >
> > This one uses that to plumb through drm core in order to be able to
> > handle linear tile formats without the need for drivers to roll up
> > their own implementation.
> >
> > This patch had been written with Mali-dp X0L2 and X0L0 in mind which
> > is a 1 plane YCbCr 420 format with a 2x2 tile, that uses in average 2
> > bytes per pixel and where tiles are laid out in a linear manner.
> >
> > Now what are the restrictions:
> >
> > 1. Pitch in bytes is expected to cover at least tile_h * width in
> > pixels. Due to this the places where the pitch is checked/used need to
> > be updated to take into consideration the tile_w, tile_h and
> > tile_size.
> > tile_size = cpp * tile_w * tile_h
> >
> > 2. When doing source cropping plane_src_x/y need to be a multiple of
> > tile_w/tile_h and we need to take into consideration the tile_w/tile_h
> > when computing the start address.
> >
> > For all non-tiled formats the tile_w and tile_h will be 1, so if I
> > didn't miss anything nothing should change.
> >
> > Regarding multi-planar linear tile formats, I'm not sure how those
> > should be handle I kind of assumed that tile_h/tile_w will have to be
> > divided by horizontal/subsampling. Anyway, I think it's best to just
> > put an warning in there and handle it when someone tries to add
> > support for them.
> >
> > Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe at arm.com>
> > ---
> > drivers/gpu/drm/drm_atomic.c | 8 +++
> > drivers/gpu/drm/drm_fb_cma_helper.c | 11 ++++-
> > drivers/gpu/drm/drm_fourcc.c | 52 ++++++++++++++++++++
> > drivers/gpu/drm/drm_framebuffer.c | 19 +++++--
> > drivers/gpu/drm/drm_gem_framebuffer_helper.c | 10 ++--
> > include/drm/drm_fourcc.h | 2 +
> > 6 files changed, 94 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> > index 3eb061e11e2e..7a3e893a4cd1 100644
> > --- a/drivers/gpu/drm/drm_atomic.c
> > +++ b/drivers/gpu/drm/drm_atomic.c
> > @@ -1087,6 +1087,14 @@ static int drm_atomic_plane_check(struct drm_plane *plane,
> > return -ENOSPC;
> > }
> >
> > + /* Make sure source coordinates are a multiple of tile sizes */
> > + if ((state->src_x >> 16) % state->fb->format->tile_w ||
> > + (state->src_y >> 16) % state->fb->format->tile_h) {
> > + DRM_DEBUG_ATOMIC("[PLANE:%d:%s] Source coordinates do not meet tile restrictions",
> > + plane->base.id, plane->name);
> > + return -EINVAL;
> > + }
> > +
> > if (plane_switching_crtc(state->state, plane, state)) {
> > DRM_DEBUG_ATOMIC("[PLANE:%d:%s] switching CRTC directly\n",
> > plane->base.id, plane->name);
> > diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c
> > index 47e0e2f6642d..4d8052adce67 100644
> > --- a/drivers/gpu/drm/drm_fb_cma_helper.c
> > +++ b/drivers/gpu/drm/drm_fb_cma_helper.c
> > @@ -87,6 +87,8 @@ dma_addr_t drm_fb_cma_get_gem_addr(struct drm_framebuffer *fb,
> > struct drm_gem_cma_object *obj;
> > dma_addr_t paddr;
> > u8 h_div = 1, v_div = 1;
> > + u32 tile_w = drm_format_tile_width(fb->format, plane);
> > + u32 tile_h = drm_format_tile_height(fb->format, plane);
> >
> > obj = drm_fb_cma_get_gem_obj(fb, plane);
> > if (!obj)
> > @@ -99,8 +101,13 @@ dma_addr_t drm_fb_cma_get_gem_addr(struct drm_framebuffer *fb,
> > v_div = fb->format->vsub;
> > }
> >
> > - paddr += (fb->format->cpp[plane] * (state->src_x >> 16)) / h_div;
> > - paddr += (fb->pitches[plane] * (state->src_y >> 16)) / v_div;
> > + paddr += (fb->format->cpp[plane] * tile_w * (state->src_x >> 16))
> > + / h_div;
> > + /*
> > + * For tile formats pitches are expected to cover at least
> > + * width * tile_h pixels
> > + */
> > + paddr += ((fb->pitches[plane] / tile_h) * (state->src_y >> 16)) / v_div;
> >
> > return paddr;
> > }
> > diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> > index f55cd93ba2d0..d6c9c5aa4036 100644
> > --- a/drivers/gpu/drm/drm_fourcc.c
> > +++ b/drivers/gpu/drm/drm_fourcc.c
> > @@ -557,3 +557,55 @@ int drm_format_plane_height(int height, uint32_t format, int plane)
> > return height / info->vsub;
> > }
> > EXPORT_SYMBOL(drm_format_plane_height);
> > +
> > +/**
> > + * drm_format_tile_width - width of a tile for tile formats, should be 1 for all
> > + * non-tiled formats.
> > + * @format: pixel format
> > + * @plane: plane index
> > + *
> > + * Returns:
> > + * The width of a tile, depending on the plane index and horizontal sub-sampling
> > + */
> > +uint32_t drm_format_tile_width(const struct drm_format_info *info, int plane)
> > +{
> > + WARN_ON(!info->tile_w);
> > + if (plane == 0 || info->tile_w == 1)
> > + return info->tile_w;
> > +
> > + /*
> > + * Multi planar tiled formats have never been tested, check that
> > + * buffer restrictions and source cropping meet the format layout
> > + * expectations.
> > + */
> > + WARN_ON("Multi-planar tiled formats unsupported");
> > + WARN_ON(info->tile_w % info->hsub);
> > + return info->tile_w / info->hsub;
> > +}
> > +EXPORT_SYMBOL(drm_format_tile_width);
> > +
> > +/**
> > + * drm_format_tile_height - height of a tile for tile formats, should be 1 for
> > + * all non-tiled formats.
> > + * @format: pixel format
> > + * @plane: plane index
> > + *
> > + * Returns:
> > + * The height of a tile, depending on the plane index and vertical sub-sampling
> > + */
> > +uint32_t drm_format_tile_height(const struct drm_format_info *info, int plane)
> > +{
> > + WARN_ON(!info->tile_h);
> > + if (plane == 0 || info->tile_h == 1)
> > + return info->tile_h;
> > +
> > + /*
> > + * Multi planar tiled formats have never been tested, check that
> > + * buffer restrictions and source cropping meet the format layout
> > + * expectations.
> > + */
> > + WARN_ON("Multi-planar tiled formats unsupported");
> > + WARN_ON(info->tile_h % info->vsub);
> > + return info->tile_h / info->vsub;
> > +}
> > +EXPORT_SYMBOL(drm_format_tile_height);
> > diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
> > index 781af1d42d76..57509e51cb80 100644
> > --- a/drivers/gpu/drm/drm_framebuffer.c
> > +++ b/drivers/gpu/drm/drm_framebuffer.c
> > @@ -191,19 +191,32 @@ static int framebuffer_check(struct drm_device *dev,
> > unsigned int width = fb_plane_width(r->width, info, i);
> > unsigned int height = fb_plane_height(r->height, info, i);
> > unsigned int cpp = info->cpp[i];
> > + unsigned int tile_w = drm_format_tile_width(info, i);
> > + unsigned int tile_h = drm_format_tile_height(info, i);
> > + unsigned int tile_size = cpp * tile_w * tile_h;
> > + unsigned int num_htiles;
> > + unsigned int num_vtiles;
> >
> > if (!r->handles[i]) {
> > DRM_DEBUG_KMS("no buffer object handle for plane %d\n", i);
> > return -EINVAL;
> > }
> >
> > - if ((uint64_t) width * cpp > UINT_MAX)
> > + if ((width % tile_w) || (height % tile_h)) {
>
> I think this is too strict. You can carve out a sub-part of anything
> really with a drm_framebuffer. See below, we only checked that width * cpp
> < pitches, so leftover bytes/bits was always ok.
>
> Your driver might have additional constraints, but that's a different
> story.
This seem like the only thing that we have in common with
DRM_FORMAT_MOD_SAMSUNG_64_32_TILE/NV12MT, which is even more
restrictive than that and it wants the width to be a multiple of 128.
>
> > + DRM_DEBUG_KMS("buffer width/height need to be a multiple of tile dimensions\n");
> > + return -EINVAL;
> > + }
> > +
> > + num_htiles = width / tile_w;
> > + num_vtiles = height / tile_h;
> > +
> > + if ((uint64_t)num_htiles * tile_size > UINT_MAX)
> > return -ERANGE;
> >
> > - if ((uint64_t) height * r->pitches[i] + r->offsets[i] > UINT_MAX)
> > + if ((uint64_t)num_vtiles * r->pitches[i] + r->offsets[i] > UINT_MAX)
> > return -ERANGE;
> >
> > - if (r->pitches[i] < width * cpp) {
> > + if (r->pitches[i] < num_htiles * tile_size) {
>
> Essentially you define ->pitches now to mean a row of tiles. At least for
> bigger tiled formats (using modifiers) we don't use it like that. But it
> also gets awkward quickly if we keep pitches to mean bytes in one row of
> pixels. For that case we'd have
That's how everything started, we have already internal userspace and
drivers that expect and pass pitch as a row of tiles in bytes.
For the tiles format in this patchset(X0L2/X0L0) which orders the tiles
in linear manner the pitch will at least get you at the beginning of a
row.
I'm not sure I understand what's the meaning of a pitch for
DRM_FORMAT_MOD_SAMSUNG_64_32_TILE which orders the tiles in Z shape.
How far will a pitch for this format get you, it seems that using just
witdth * cpp will get you somewhere in the middle.
>
> pitches % (cpp * tile_w) == 0
> pitches * align(height, tile_h) < size
>
> That's at least the definition of tiling we've used in i915. It also
> matches what we've done for DRM_FORMAT_MOD_SAMSUNG_64_32_TILE.
>
> This definition of pitches becomes a bit nonsense for fractional cpp, but
> well, cpp is by definition not fractional, so we can figure that out when
> we actually have that problem.
> -Daniel
>
> > DRM_DEBUG_KMS("bad pitch %u for plane %d\n", r->pitches[i], i);
> > return -EINVAL;
> > }
> > diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> > index 2810d4131411..3d01a1a9d5d2 100644
> > --- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> > +++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> > @@ -161,6 +161,11 @@ drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
> > unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
> > unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
> > unsigned int min_size;
> > + unsigned int tile_w = drm_format_tile_width(info, i);
> > + unsigned int tile_h = drm_format_tile_height(info, i);
> > + unsigned int tile_size = info->cpp[i] * tile_w * tile_h;
> > + unsigned int num_htiles = width / tile_w;
> > + unsigned int num_vtiles = height / tile_h;
> >
> > objs[i] = drm_gem_object_lookup(file, mode_cmd->handles[i]);
> > if (!objs[i]) {
> > @@ -169,9 +174,8 @@ drm_gem_fb_create_with_funcs(struct drm_device *dev, struct drm_file *file,
> > goto err_gem_object_put;
> > }
> >
> > - min_size = (height - 1) * mode_cmd->pitches[i]
> > - + width * info->cpp[i]
> > - + mode_cmd->offsets[i];
> > + min_size = (num_vtiles - 1) * mode_cmd->pitches[i]
> > + + num_htiles * tile_size + mode_cmd->offsets[i];
> >
> > if (objs[i]->size < min_size) {
> > drm_gem_object_put_unlocked(objs[i]);
> > diff --git a/include/drm/drm_fourcc.h b/include/drm/drm_fourcc.h
> > index 41681cf2b140..001afca9bcff 100644
> > --- a/include/drm/drm_fourcc.h
> > +++ b/include/drm/drm_fourcc.h
> > @@ -76,6 +76,8 @@ int drm_format_horz_chroma_subsampling(uint32_t format);
> > int drm_format_vert_chroma_subsampling(uint32_t format);
> > int drm_format_plane_width(int width, uint32_t format, int plane);
> > int drm_format_plane_height(int height, uint32_t format, int plane);
> > +uint32_t drm_format_tile_width(const struct drm_format_info *info, int plane);
> > +uint32_t drm_format_tile_height(const struct drm_format_info *info, int plane);
> > const char *drm_get_format_name(uint32_t format, struct drm_format_name_buf *buf);
> >
> > #endif /* __DRM_FOURCC_H__ */
> > --
> > 2.18.0
> >
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
--
Cheers,
Alex G
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