pan/midgard: Support indirect UBO offsets

...in case we have arrays in a UBO block that we'd like to access
indirectly.

Signed-off-by: Alyssa Rosenzweig <[email protected]>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3352>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3352>

2 files changed, 7 insertions, 22 deletions

diff --git a/src/panfrost/midgard/compiler.h b/src/panfrost/midgard/compiler.h
index 18ff2572b48..936d2232bae 100644
--- a/src/panfrost/midgard/compiler.h
+++ b/src/panfrost/midgard/compiler.h
@@ -663,15 +663,6 @@ bool mir_is_live_after(compiler_context *ctx, midgard_block *block, midgard_inst
 void mir_create_pipeline_registers(compiler_context *ctx);
 void midgard_promote_uniforms(compiler_context *ctx);
 
-midgard_instruction *
-emit_ubo_read(
-        compiler_context *ctx,
-        nir_instr *instr,
-        unsigned dest,
-        unsigned offset,
-        nir_src *indirect_offset,
-        unsigned index);
-
 void
 emit_sysval_read(compiler_context *ctx, nir_instr *instr, signed dest_override, unsigned nr_components);
 
diff --git a/src/panfrost/midgard/midgard_compile.c b/src/panfrost/midgard/midgard_compile.c
index efd9f483de5..2dd58b714f8 100644
--- a/src/panfrost/midgard/midgard_compile.c
+++ b/src/panfrost/midgard/midgard_compile.c
@@ -1121,13 +1121,14 @@ mir_set_intr_mask(nir_instr *instr, midgard_instruction *ins, bool is_read)
 /* Uniforms and UBOs use a shared code path, as uniforms are just (slightly
  * optimized) versions of UBO #0 */
 
-midgard_instruction *
+static midgard_instruction *
 emit_ubo_read(
         compiler_context *ctx,
         nir_instr *instr,
         unsigned dest,
         unsigned offset,
         nir_src *indirect_offset,
+        unsigned indirect_shift,
         unsigned index)
 {
         /* TODO: half-floats */
@@ -1140,7 +1141,7 @@ emit_ubo_read(
 
         if (indirect_offset) {
                 ins.src[2] = nir_src_index(ctx, indirect_offset);
-                ins.load_store.arg_2 = 0x80;
+                ins.load_store.arg_2 = (indirect_shift << 5);
         } else {
                 ins.load_store.arg_2 = 0x1E;
         }
@@ -1313,7 +1314,7 @@ emit_sysval_read(compiler_context *ctx, nir_instr *instr, signed dest_override,
 
         /* Emit the read itself -- this is never indirect */
         midgard_instruction *ins =
-                emit_ubo_read(ctx, instr, dest, uniform * 16, NULL, 0);
+                emit_ubo_read(ctx, instr, dest, uniform * 16, NULL, 0, 0);
 
         ins->mask = mask_of(nr_components);
 }
@@ -1450,22 +1451,15 @@ emit_intrinsic(compiler_context *ctx, nir_intrinsic_instr *instr)
                 reg = nir_dest_index(ctx, &instr->dest);
 
                 if (is_uniform && !ctx->is_blend) {
-                        emit_ubo_read(ctx, &instr->instr, reg, (ctx->sysval_count + offset) * 16, indirect_offset, 0);
+                        emit_ubo_read(ctx, &instr->instr, reg, (ctx->sysval_count + offset) * 16, indirect_offset, 4, 0);
                 } else if (is_ubo) {
                         nir_src index = instr->src[0];
 
-                        /* We don't yet support indirect UBOs. For indirect
-                         * block numbers (if that's possible), we don't know
-                         * enough about the hardware yet. For indirect sources,
-                         * we know what we need but we need to add some NIR
-                         * support for lowering correctly with respect to
-                         * 128-bit reads */
-
+                        /* TODO: Is indirect block number possible? */
                         assert(nir_src_is_const(index));
-                        assert(nir_src_is_const(*src_offset));
 
                         uint32_t uindex = nir_src_as_uint(index) + 1;
-                        emit_ubo_read(ctx, &instr->instr, reg, offset, NULL, uindex);
+                        emit_ubo_read(ctx, &instr->instr, reg, offset, indirect_offset, 0, uindex);
                 } else if (is_ssbo) {
                         nir_src index = instr->src[0];
                         assert(nir_src_is_const(index));