panfrost: enable EXT_shader_pixel_local_storage

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Eric R. Smith <eric.smith@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37110>

docs/features.txt

@@ -336,6 +336,7 @@ Khronos, ARB, and OES extensions that are not part of any OpenGL or OpenGL ES ve
   GL_EXT_semaphore_win32                                DONE (zink, d3d12)
   GL_EXT_shader_clock                                   DONE (all drivers that support GL_ARB_shader_clock)
   GL_EXT_shader_group_vote                              DONE (all drivers that support GL_ARB_shader_group_vote)
+  GL_EXT_shader_pixel_local_storage                     DONE (panfrost/v6+)
   GL_EXT_shader_realtime_clock                          DONE (panfrost/v6+)
   GL_EXT_sRGB_write_control                             DONE (all drivers that support GLES 3.0+)
   GL_EXT_texture_compression_astc_decode_mode           DONE (panfrost)

docs/relnotes/new_features.txt

@@ -11,3 +11,4 @@ VK_EXT_shader_uniform_buffer_unsized_array on NVK, RADV
 VK_EXT_device_memory_report on panvk
 VK_VALVE_video_encode_rgb_conversion on radv
 VK_EXT_custom_resolve on RADV
+GL_EXT_shader_pixel_local_storage on Panfrost v6+

src/gallium/drivers/panfrost/pan_cmdstream.c

@@ -4459,6 +4459,17 @@ emit_write_timestamp(struct panfrost_batch *batch,
    JOBX(emit_write_timestamp)(batch, dst, offset);
 }
 
+static uint64_t
+get_conv_desc(enum pipe_format fmt, unsigned rt,
+              unsigned force_size, bool dithered)
+{
+#if PAN_ARCH >= 6
+   return GENX(pan_blend_get_internal_desc)(fmt, rt, force_size, dithered) >> 32;
+#else
+   return 0;
+#endif
+}
+
 void
 GENX(panfrost_cmdstream_screen_init)(struct panfrost_screen *screen)
 {
@@ -4479,6 +4490,7 @@ GENX(panfrost_cmdstream_screen_init)(struct panfrost_screen *screen)
    screen->vtbl.mtk_detile = panfrost_mtk_detile_compute;
    screen->vtbl.emit_write_timestamp = emit_write_timestamp;
    screen->vtbl.select_tile_size = GENX(pan_select_tile_size);
+   screen->vtbl.get_conv_desc = get_conv_desc;
 
    pan_blend_shader_cache_init(&dev->blend_shaders, panfrost_device_gpu_id(dev),
                                dev->kmod.props.gpu_variant,

src/gallium/drivers/panfrost/pan_cmdstream.h

@@ -232,6 +232,10 @@ panfrost_fs_required(struct panfrost_compiled_shader *fs,
    if (PAN_ARCH <= 5 && zsa->base.alpha_func != PIPE_FUNC_ALWAYS)
       return true;
 
+   /* if pixel local storage is enabled we need to execute */
+   if (state->pls_enabled)
+      return true;
+
    /* If colour is written we need to execute */
    for (unsigned i = 0; i < state->nr_cbufs; ++i) {
       if (state->cbufs[i].texture && blend->info[i].enabled)

src/gallium/drivers/panfrost/pan_job.c

@@ -495,6 +495,7 @@ panfrost_batch_to_fb_info(const struct panfrost_batch *batch,
    fb->nr_samples = util_framebuffer_get_num_samples(&batch->key);
    fb->force_samples = (batch->line_smoothing == U_TRISTATE_YES) ? 16 : 0;
    fb->rt_count = batch->key.nr_cbufs;
+   fb->pls_enabled = batch->key.pls_enabled;
    fb->sprite_coord_origin = (batch->sprite_coord_origin == U_TRISTATE_YES);
    fb->first_provoking_vertex =
       (batch->first_provoking_vertex == U_TRISTATE_YES);

src/gallium/drivers/panfrost/pan_screen.c

@@ -731,6 +731,10 @@ panfrost_init_screen_caps(struct panfrost_screen *screen)
    caps->shader_realtime_clock = dev->arch >= 6 &&
       dev->kmod.props.gpu_can_query_timestamp;
 
+   /* pixel_local_storage is initially for valhall and bifrost only */
+   caps->shader_pixel_local_storage_fast_size =
+      caps->shader_pixel_local_storage_size = (dev->arch >= 6) ? 16 : 0;
+
    caps->vs_instanceid = true;
    caps->texture_multisample = true;
    caps->surface_sample_count = true;

src/gallium/drivers/panfrost/pan_screen.h

@@ -110,6 +110,10 @@ struct panfrost_vtable {
 
    /* Run a compute shader to detile an MTK 16L32 image */
    void (*mtk_detile)(struct panfrost_context *ctx, struct pipe_blit_info *info);
+
+   /* construct a render target blend descriptor */
+   uint64_t (*get_conv_desc)(enum pipe_format fmt, unsigned rt,
+                             unsigned force_size, bool dithered);
 };
 
 struct panfrost_screen {

src/gallium/drivers/panfrost/pan_shader.c

@@ -145,6 +145,7 @@ panfrost_shader_compile(struct panfrost_screen *screen, const nir_shader *ir,
    struct pan_compile_inputs inputs = {
       .gpu_id = panfrost_device_gpu_id(dev),
       .gpu_variant = dev->kmod.props.gpu_variant,
+      .get_conv_desc = screen->vtbl.get_conv_desc,
    };
 
    /* Lower this early so the backends don't have to worry about it */
@@ -502,6 +503,42 @@ panfrost_create_shader_state(struct pipe_context *pctx,
    so->stream_output = cso->stream_output;
    so->nir = nir;
 
+   /* PLS lowering is not taken care of by glsl_to_nir(), so do it here. */
+   if (nir->info.stage == MESA_SHADER_FRAGMENT &&
+       nir->info.fs.accesses_pixel_local_storage) {
+      /* Try to optimize the case where inout PLS vars are never
+       * read/written to. Needs to be called before
+       * nir_lower_io_vars_to_temporaries() because the copy_derefs
+       * inserted there prevent us from detecting PLS usage.
+       */
+      NIR_PASS(_, nir, nir_downgrade_pls_vars);
+
+      /* Lower PLS vars to temporaries before we lower IOs. */
+      NIR_PASS(_, nir, nir_lower_io_vars_to_temporaries,
+               nir_shader_get_entrypoint(nir), nir_var_any_pixel_local);
+
+      /* We need to lower all the copy_deref's introduced by lower_io_to-
+       * _temporaries before calling nir_lower_io.
+       */
+      NIR_PASS(_, nir, nir_split_var_copies);
+      NIR_PASS(_, nir, nir_lower_var_copies);
+      NIR_PASS(_, nir, nir_lower_global_vars_to_local);
+
+      /* Lower all PLS IOs. */
+      NIR_PASS(_, nir, nir_lower_io, nir_var_any_pixel_local, glsl_type_size,
+               0);
+
+      /* Lower and remove dead derefs and variables to clean up the IR. */
+      NIR_PASS(_, nir, nir_lower_vars_to_ssa);
+      NIR_PASS(_, nir, nir_opt_dce);
+      NIR_PASS(_, nir, nir_remove_dead_variables, nir_var_function_temp, NULL);
+
+      /* Re-run gather_info() to get the latest accesses_pixel_local_storage
+       * state.
+       */
+      nir_shader_gather_info(nir, nir_shader_get_entrypoint(nir));
+   }
+
    /* gl_FragColor needs to be lowered before lowering I/O, do that now */
    if (nir->info.stage == MESA_SHADER_FRAGMENT &&
        nir->info.outputs_written & BITFIELD_BIT(FRAG_RESULT_COLOR)) {

src/panfrost/ci/panfrost-g52-gles2-extensions.txt

@@ -46,6 +46,7 @@ GL_EXT_shader_framebuffer_fetch_non_coherent
 GL_EXT_shader_implicit_conversions
 GL_EXT_shader_integer_mix
 GL_EXT_shader_io_blocks
+GL_EXT_shader_pixel_local_storage
 GL_EXT_shader_realtime_clock
 GL_EXT_shadow_samplers
 GL_EXT_sRGB

src/panfrost/ci/panfrost-g57-gles2-extensions.txt

@@ -45,6 +45,7 @@ GL_EXT_shader_framebuffer_fetch_non_coherent
 GL_EXT_shader_implicit_conversions
 GL_EXT_shader_integer_mix
 GL_EXT_shader_io_blocks
+GL_EXT_shader_pixel_local_storage
 GL_EXT_shader_realtime_clock
 GL_EXT_shadow_samplers
 GL_EXT_sRGB

src/panfrost/ci/panfrost-g610-gles2-extensions.txt

@@ -45,6 +45,7 @@ GL_EXT_shader_framebuffer_fetch_non_coherent
 GL_EXT_shader_implicit_conversions
 GL_EXT_shader_integer_mix
 GL_EXT_shader_io_blocks
+GL_EXT_shader_pixel_local_storage
 GL_EXT_shader_realtime_clock
 GL_EXT_shadow_samplers
 GL_EXT_sRGB

src/panfrost/ci/panfrost-g72-gles2-extensions.txt

@@ -46,6 +46,7 @@ GL_EXT_shader_framebuffer_fetch_non_coherent
 GL_EXT_shader_implicit_conversions
 GL_EXT_shader_integer_mix
 GL_EXT_shader_io_blocks
+GL_EXT_shader_pixel_local_storage
 GL_EXT_shader_realtime_clock
 GL_EXT_shadow_samplers
 GL_EXT_sRGB