v3d: Emit the VCM_CACHE_SIZE packet.

This is needed to ensure that we don't get blocked waiting for VPM space
with bin/render overlapping.

Cc: "18.2" <[email protected]>

1 files changed, 19 insertions, 1 deletions

diff --git a/src/broadcom/compiler/vir.c b/src/broadcom/compiler/vir.c
index fc0b34d4453..1c8223165c6 100644
--- a/src/broadcom/compiler/vir.c
+++ b/src/broadcom/compiler/vir.c
@@ -756,10 +756,28 @@ uint64_t *v3d_compile_vs(const struct v3d_compiler *compiler,
         if (prog_data->uses_iid)
                 prog_data->vpm_input_size++;
 
-        /* Input/output segment size are in 8x32-bit multiples. */
+        /* Input/output segment size are in sectors (8 rows of 32 bits per
+         * channel).
+         */
         prog_data->vpm_input_size = align(prog_data->vpm_input_size, 8) / 8;
         prog_data->vpm_output_size = align(c->num_vpm_writes, 8) / 8;
 
+        /* Compute VCM cache size.  We set up our program to take up less than
+         * half of the VPM, so that any set of bin and render programs won't
+         * run out of space.  We need space for at least one input segment,
+         * and then allocate the rest to output segments (one for the current
+         * program, the rest to VCM).  The valid range of the VCM cache size
+         * field is 1-4 16-vertex batches, but GFXH-1744 limits us to 2-4
+         * batches.
+         */
+        assert(c->devinfo->vpm_size);
+        int sector_size = 16 * sizeof(uint32_t) * 8;
+        int vpm_size_in_sectors = c->devinfo->vpm_size / sector_size;
+        int half_vpm = vpm_size_in_sectors / 2;
+        int vpm_output_batches = half_vpm - prog_data->vpm_input_size;
+        assert(vpm_output_batches >= 2);
+        prog_data->vcm_cache_size = CLAMP(vpm_output_batches - 1, 2, 4);
+
         return v3d_return_qpu_insts(c, final_assembly_size);
 }