pan/texture: Accept holes in the pan_image_view::planes array

We are about to add multiplanar depth/stencil support. A stencil
only view of a multiplanar d32_s8 format will have NULL depth plane
(plane0), so we need to prepare the texture logic to deal with that.

Signed-off-by: Rebecca Mckeever <rebecca.mckeever@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Lars-Ivar Hesselberg Simonsen <lars-ivar.simonsen@arm.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32275>

src/panfrost/lib/pan_desc.c

@@ -66,8 +66,11 @@ mali_sampling_mode(const struct pan_image_view *view)
    unsigned nr_samples = pan_image_view_get_nr_samples(view);
 
    if (nr_samples > 1) {
+      ASSERTED const struct pan_image *first_plane =
+         pan_image_view_get_first_plane(view);
+
       assert(view->nr_samples == nr_samples);
-      assert(view->planes[0]->layout.slices[0].surface_stride != 0);
+      assert(first_plane->layout.slices[0].surface_stride != 0);
       return MALI_MSAA_LAYERED;
    }
 
@@ -86,7 +89,8 @@ static bool
 renderblock_fits_in_single_pass(const struct pan_image_view *view,
                                 unsigned tile_size)
 {
-   uint64_t mod = view->planes[0]->layout.modifier;
+   const struct pan_image *first_plane = pan_image_view_get_first_plane(view);
+   uint64_t mod = first_plane->layout.modifier;
 
    if (!drm_is_afbc(mod))
       return tile_size >= 16 * 16;
@@ -512,9 +516,10 @@ pan_prepare_rt(const struct pan_fb_info *fb, unsigned layer_idx,
 
    cfg->dithering_enable = true;
 
+   const struct pan_image *first_plane = pan_image_view_get_first_plane(rt);
    unsigned level = rt->first_level;
    ASSERTED unsigned layer_count = rt->dim == MALI_TEXTURE_DIMENSION_3D
-                                      ? rt->planes[0]->layout.depth
+                                      ? first_plane->layout.depth
                                       : rt->last_layer - rt->first_layer + 1;
 
    assert(rt->last_level == rt->first_level);

src/panfrost/lib/pan_texture.c

@@ -622,10 +622,10 @@ void
 GENX(panfrost_new_texture)(const struct pan_image_view *iview, void *out,
                            const struct panfrost_ptr *payload)
 {
-   const struct pan_image *base_image = pan_image_view_get_plane(iview, 0);
-   const struct pan_image_layout *layout = &base_image->layout;
    enum pipe_format format = iview->format;
    const struct util_format_description *desc = util_format_description(format);
+   const struct pan_image *first_plane = pan_image_view_get_first_plane(iview);
+   const struct pan_image_layout *layout = &first_plane->layout;
    uint32_t mali_format = GENX(panfrost_format_from_pipe_format)(format)->hw;
    unsigned char swizzle[4];
 

src/panfrost/lib/pan_texture.h

@@ -162,12 +162,39 @@ pan_image_view_get_plane(const struct pan_image_view *iview, uint32_t idx)
    return iview->planes[idx];
 }
 
+static inline unsigned
+pan_image_view_get_plane_mask(const struct pan_image_view *iview)
+{
+   unsigned mask = 0;
+
+   for (unsigned i = 0; i < ARRAY_SIZE(iview->planes); i++) {
+      if (iview->planes[i])
+         mask |= BITFIELD_BIT(i);
+   }
+
+   return mask;
+}
+
+static inline unsigned
+pan_image_view_get_first_plane_idx(const struct pan_image_view *iview)
+{
+   unsigned mask = pan_image_view_get_plane_mask(iview);
+
+   assert(mask);
+   return ffs(mask) - 1;
+}
+
+static inline const struct pan_image *
+pan_image_view_get_first_plane(const struct pan_image_view *iview)
+{
+   unsigned first_plane_idx = pan_image_view_get_first_plane_idx(iview);
+   return pan_image_view_get_plane(iview, first_plane_idx);
+}
+
 static inline uint32_t
 pan_image_view_get_nr_samples(const struct pan_image_view *iview)
 {
-   /* All planes should have the same nr_samples value, so we
-    * just pick the first plane. */
-   const struct pan_image *image = pan_image_view_get_plane(iview, 0);
+   const struct pan_image *image = pan_image_view_get_first_plane(iview);
 
    if (!image)
       return 0;