intel/blorp: Add support for more format bitcasting

nir_format_bitcast_uint_vec_unmasked can only be used to cast between
formats with uniform channel sizes.  In particular, it cannot handle
10_10_10_2 formats.  By making use of the NIR helper for uint vector
casts, we should now be able to bitcast between any two uint formats so
long as their channels are in RGBA order (possibly with channels
missing).  In order to do this we need to rework the key a bit to pass
the actual formats instead of just the number of bits in each.

Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>

src/intel/blorp/blorp_blit.c

@@ -871,17 +871,71 @@ bit_cast_color(struct nir_builder *b, nir_ssa_def *color,
 {
    assert(key->texture_data_type == nir_type_uint);
 
-   /* We don't actually know how many source channels we have and NIR will
-    * assert if the number of destination channels ends up being more than 4.
-    * Choose the largest number of source channels that won't over-fill a
-    * destination vec4.
-    */
-   const unsigned src_channels =
-      MIN2(4, (4 * key->dst_bpc) / key->src_bpc);
-   color = nir_channels(b, color, (1 << src_channels) - 1);
+   if (key->src_format == key->dst_format)
+      return color;
 
-   color = nir_format_bitcast_uint_vec_unmasked(b, color, key->src_bpc,
-                                                key->dst_bpc);
+   const struct isl_format_layout *src_fmtl =
+      isl_format_get_layout(key->src_format);
+   const struct isl_format_layout *dst_fmtl =
+      isl_format_get_layout(key->dst_format);
+
+   /* They must be uint formats with the same bit size */
+   assert(src_fmtl->bpb == dst_fmtl->bpb);
+   assert(src_fmtl->channels.r.type == ISL_UINT);
+   assert(dst_fmtl->channels.r.type == ISL_UINT);
+
+   /* They must be in regular color formats (no luminance or alpha) */
+   assert(src_fmtl->channels.r.bits > 0);
+   assert(dst_fmtl->channels.r.bits > 0);
+
+   /* They must be in RGBA order (possibly with channels missing) */
+   assert(src_fmtl->channels.r.start_bit == 0);
+   assert(dst_fmtl->channels.r.start_bit == 0);
+
+   if (src_fmtl->bpb <= 32) {
+      const unsigned src_channels =
+         isl_format_get_num_channels(key->src_format);
+      const unsigned src_bits[4] = {
+         src_fmtl->channels.r.bits,
+         src_fmtl->channels.g.bits,
+         src_fmtl->channels.b.bits,
+         src_fmtl->channels.a.bits,
+      };
+      const unsigned dst_channels =
+         isl_format_get_num_channels(key->dst_format);
+      const unsigned dst_bits[4] = {
+         dst_fmtl->channels.r.bits,
+         dst_fmtl->channels.g.bits,
+         dst_fmtl->channels.b.bits,
+         dst_fmtl->channels.a.bits,
+      };
+      nir_ssa_def *packed =
+         nir_format_pack_uint_unmasked(b, color, src_bits, src_channels);
+      color = nir_format_unpack_uint(b, packed, dst_bits, dst_channels);
+   } else {
+      const unsigned src_bpc = src_fmtl->channels.r.bits;
+      const unsigned dst_bpc = dst_fmtl->channels.r.bits;
+
+      assert(src_fmtl->channels.g.bits == 0 ||
+             src_fmtl->channels.g.bits == src_fmtl->channels.r.bits);
+      assert(src_fmtl->channels.b.bits == 0 ||
+             src_fmtl->channels.b.bits == src_fmtl->channels.r.bits);
+      assert(src_fmtl->channels.a.bits == 0 ||
+             src_fmtl->channels.a.bits == src_fmtl->channels.r.bits);
+      assert(dst_fmtl->channels.g.bits == 0 ||
+             dst_fmtl->channels.g.bits == dst_fmtl->channels.r.bits);
+      assert(dst_fmtl->channels.b.bits == 0 ||
+             dst_fmtl->channels.b.bits == dst_fmtl->channels.r.bits);
+      assert(dst_fmtl->channels.a.bits == 0 ||
+             dst_fmtl->channels.a.bits == dst_fmtl->channels.r.bits);
+
+      /* Restrict to only the channels we actually have */
+      const unsigned src_channels =
+         isl_format_get_num_channels(key->src_format);
+      color = nir_channels(b, color, (1 << src_channels) - 1);
+
+      color = nir_format_bitcast_uint_vec_unmasked(b, color, src_bpc, dst_bpc);
+   }
 
    /* Blorp likes to assume that colors are vec4s */
    nir_ssa_def *u = nir_ssa_undef(b, 1, 32);
@@ -1321,14 +1375,13 @@ brw_blorp_build_nir_shader(struct blorp_context *blorp, void *mem_ctx,
                             nir_type_int);
    }
 
-   if (key->dst_bpc != key->src_bpc) {
+   if (key->format_bit_cast) {
       assert(isl_swizzle_is_identity(key->src_swizzle));
       assert(isl_swizzle_is_identity(key->dst_swizzle));
       color = bit_cast_color(&b, color, key);
-   }
-
-   if (key->dst_format)
+   } else if (key->dst_format) {
       color = convert_color(&b, color, key);
+   }
 
    if (key->dst_rgb) {
       /* The destination image is bound as a red texture three times as wide
@@ -2522,10 +2575,26 @@ blorp_copy(struct blorp_batch *batch,
                              params.dst.view.format, packed);
    }
 
-   wm_prog_key.src_bpc =
-      isl_format_get_layout(params.src.view.format)->channels.r.bits;
-   wm_prog_key.dst_bpc =
-      isl_format_get_layout(params.dst.view.format)->channels.r.bits;
+   if (params.src.view.format != params.dst.view.format) {
+      enum isl_format src_cast_format = params.src.view.format;
+      enum isl_format dst_cast_format = params.dst.view.format;
+
+      /* The BLORP bitcast code gets confused by RGB formats.  Just treat them
+       * as RGBA and then everything will be happy.  This is perfectly safe
+       * because BLORP likes to treat things as if they have vec4 colors all
+       * the time anyway.
+       */
+      if (isl_format_is_rgb(src_cast_format))
+         src_cast_format = isl_format_rgb_to_rgba(src_cast_format);
+      if (isl_format_is_rgb(dst_cast_format))
+         dst_cast_format = isl_format_rgb_to_rgba(dst_cast_format);
+
+      if (src_cast_format != dst_cast_format) {
+         wm_prog_key.format_bit_cast = true;
+         wm_prog_key.src_format = src_cast_format;
+         wm_prog_key.dst_format = dst_cast_format;
+      }
+   }
 
    if (src_fmtl->bw > 1 || src_fmtl->bh > 1) {
       blorp_surf_convert_to_uncompressed(batch->blorp->isl_dev, &params.src,

src/intel/blorp/blorp_priv.h

@@ -246,8 +246,11 @@ struct brw_blorp_blit_prog_key
    /* The swizzle to apply to the source in the shader */
    struct isl_swizzle src_swizzle;
 
-   /* Number of bits per channel in the source image. */
-   uint8_t src_bpc;
+   /* The format of the source if format-specific workarounds are needed
+    * and 0 (ISL_FORMAT_R32G32B32A32_FLOAT) if the destination is natively
+    * renderable.
+    */
+   enum isl_format src_format;
 
    /* True if the source requires normalized coordinates */
    bool src_coords_normalized;
@@ -269,15 +272,15 @@ struct brw_blorp_blit_prog_key
    /* The swizzle to apply to the destination in the shader */
    struct isl_swizzle dst_swizzle;
 
-   /* Number of bits per channel in the destination image. */
-   uint8_t dst_bpc;
-
    /* The format of the destination if format-specific workarounds are needed
     * and 0 (ISL_FORMAT_R32G32B32A32_FLOAT) if the destination is natively
     * renderable.
     */
    enum isl_format dst_format;
 
+   /* Whether or not the format workarounds are a bitcast operation */
+   bool format_bit_cast;
+
    /* Type of the data to be read from the texture (one of
     * nir_type_(int|uint|float)).
     */