asahi: Decompress writable images

We can't write to compressed images. Decompress on the fly if needed. mesa/st
doesn't bother to do this for us.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23480>

src/gallium/drivers/asahi/agx_pipe.c

@@ -1119,6 +1119,19 @@ transition_resource(struct pipe_context *pctx, struct agx_resource *rsrc,
    pipe_resource_reference((struct pipe_resource **)&new_res, NULL);
 }
 
+void
+agx_decompress(struct agx_context *ctx, struct agx_resource *rsrc,
+               const char *reason)
+{
+   assert(rsrc->layout.tiling == AIL_TILING_TWIDDLED_COMPRESSED);
+   perf_debug_ctx(ctx, "Decompressing resource due to %s", reason);
+
+   struct pipe_resource templ = rsrc->base;
+   assert(!(templ.bind & PIPE_BIND_SHADER_IMAGE) && "currently compressed");
+   templ.bind |= PIPE_BIND_SHADER_IMAGE /* forces off compression */;
+   transition_resource(&ctx->base, rsrc, &templ);
+}
+
 static void
 agx_flush_resource(struct pipe_context *pctx, struct pipe_resource *pres)
 {

src/gallium/drivers/asahi/agx_state.c

@@ -72,6 +72,16 @@ agx_set_shader_images(struct pipe_context *pctx, enum pipe_shader_type shader,
          continue;
       }
 
+      /* Images writeable with pixel granularity are incompatible with
+       * compression. Decompress if necessary.
+       */
+      struct agx_resource *rsrc = agx_resource(image->resource);
+      if (rsrc->layout.tiling == AIL_TILING_TWIDDLED_COMPRESSED &&
+          (image->shader_access & PIPE_IMAGE_ACCESS_WRITE)) {
+
+         agx_decompress(ctx, rsrc, "Shader image");
+      }
+
       /* FIXME: Decompress here once we have texture compression */
       util_copy_image_view(&ctx->stage[shader].images[start_slot + i], image);
    }

src/gallium/drivers/asahi/agx_state.h

@@ -634,6 +634,9 @@ agx_map_texture_gpu(struct agx_resource *rsrc, unsigned z)
           (uint64_t)ail_get_layer_offset_B(&rsrc->layout, z);
 }
 
+void agx_decompress(struct agx_context *ctx, struct agx_resource *rsrc,
+                    const char *reason);
+
 struct agx_transfer {
    struct pipe_transfer base;
    void *map;