Mesa (master): panfrost: Debitfieldize mali_uniform_buffer_meta

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Module: Mesa
Branch: master
Commit: 7d3c48f131ec84aa759a6290a20e2b0c02ad8834
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=7d3c48f131ec84aa759a6290a20e2b0c02ad8834

Author: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Date:   Sun Feb 16 17:01:02 2020 -0500

panfrost: Debitfieldize mali_uniform_buffer_meta

It fits snugly in a u64, just give a macro for direct computation rather
than fudging around with bitfields. Not sure if this actually matters
with well-optimized compilers but it makes the code subjectively cleaner
so it's worth it for that if nothing else.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3838>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3838>

---

 src/gallium/drivers/panfrost/pan_context.c | 16 +++++-----------
 src/panfrost/include/panfrost-job.h        | 29 ++++++++++++++++-------------
 src/panfrost/pandecode/decode.c            |  8 ++++----
 3 files changed, 25 insertions(+), 28 deletions(-)

diff --git a/src/gallium/drivers/panfrost/pan_context.c b/src/gallium/drivers/panfrost/pan_context.c
index 60ccf66f841..6f45901ee81 100644
--- a/src/gallium/drivers/panfrost/pan_context.c
+++ b/src/gallium/drivers/panfrost/pan_context.c
@@ -1097,12 +1097,11 @@ panfrost_emit_for_draw(struct panfrost_context *ctx, bool with_vertex_data)
                 unsigned ubo_count = panfrost_ubo_count(ctx, i);
                 assert(ubo_count >= 1);
 
-                size_t sz = sizeof(struct mali_uniform_buffer_meta) * ubo_count;
-                struct mali_uniform_buffer_meta ubos[PAN_MAX_CONST_BUFFERS];
+                size_t sz = sizeof(uint64_t) * ubo_count;
+                uint64_t ubos[PAN_MAX_CONST_BUFFERS];
 
                 /* Upload uniforms as a UBO */
-                ubos[0].size = MALI_POSITIVE((2 + uniform_count));
-                ubos[0].ptr = transfer.gpu >> 2;
+                ubos[0] = MALI_MAKE_UBO(2 + uniform_count, transfer.gpu);
 
                 /* The rest are honest-to-goodness UBOs */
 
@@ -1114,9 +1113,7 @@ panfrost_emit_for_draw(struct panfrost_context *ctx, bool with_vertex_data)
 
                         if (!enabled || empty) {
                                 /* Stub out disabled UBOs to catch accesses */
-
-                                ubos[ubo].size = 0;
-                                ubos[ubo].ptr = 0xDEAD0000;
+                                ubos[ubo] = MALI_MAKE_UBO(0, 0xDEAD0000);
                                 continue;
                         }
 
@@ -1124,10 +1121,7 @@ panfrost_emit_for_draw(struct panfrost_context *ctx, bool with_vertex_data)
 
                         unsigned bytes_per_field = 16;
                         unsigned aligned = ALIGN_POT(usz, bytes_per_field);
-                        unsigned fields = aligned / bytes_per_field;
-
-                        ubos[ubo].size = MALI_POSITIVE(fields);
-                        ubos[ubo].ptr = gpu >> 2;
+                        ubos[ubo] = MALI_MAKE_UBO(aligned / bytes_per_field, gpu);
                 }
 
                 mali_ptr ubufs = panfrost_upload_transient(batch, ubos, sz);
diff --git a/src/panfrost/include/panfrost-job.h b/src/panfrost/include/panfrost-job.h
index 940b5860e95..405440146e6 100644
--- a/src/panfrost/include/panfrost-job.h
+++ b/src/panfrost/include/panfrost-job.h
@@ -876,20 +876,23 @@ struct mali_attr_meta {
 /* ORed into an MFBD address to specify the fbx section is included */
 #define MALI_MFBD_TAG_EXTRA (0x2)
 
-struct mali_uniform_buffer_meta {
-        /* This is actually the size minus 1 (MALI_POSITIVE), in units of 16
-         * bytes. This gives a maximum of 2^14 bytes, which just so happens to
-         * be the GL minimum-maximum for GL_MAX_UNIFORM_BLOCK_SIZE.
-         */
-        u64 size : 10;
+/* Uniform buffer objects are 64-bit fields divided as:
+ *
+ *      u64 size : 10;
+ *      mali_ptr ptr : 64 - 10;
+ *
+ * The size is actually the size minus 1 (MALI_POSITIVE), in units of 16 bytes.
+ * This gives a maximum of 2^14 bytes, which just so happens to be the GL
+ * minimum-maximum for GL_MAX_UNIFORM_BLOCK_SIZE.
+ *
+ * The pointer is missing the bottom 2 bits and top 8 bits. The top 8 bits
+ * should be 0 for userspace pointers, according to
+ * https://lwn.net/Articles/718895/. By reusing these bits, we can make each
+ * entry in the table only 64 bits.
+ */
 
-        /* This is missing the bottom 2 bits and top 8 bits. The top 8 bits
-         * should be 0 for userspace pointers, according to
-         * https://lwn.net/Articles/718895/. By reusing these bits, we can make
-         * each entry in the table only 64 bits.
-         */
-        mali_ptr ptr : 64 - 10;
-};
+#define MALI_MAKE_UBO(elements, ptr) \
+        (MALI_POSITIVE((elements)) | (((ptr) >> 2) << 10))
 
 /* On Bifrost, these fields are the same between the vertex and tiler payloads.
  * They also seem to be the same between Bifrost and Midgard. They're shared in
diff --git a/src/panfrost/pandecode/decode.c b/src/panfrost/pandecode/decode.c
index 97c2a255f31..0a75e66351f 100644
--- a/src/panfrost/pandecode/decode.c
+++ b/src/panfrost/pandecode/decode.c
@@ -1783,15 +1783,15 @@ static void
 pandecode_uniform_buffers(mali_ptr pubufs, int ubufs_count, int job_no)
 {
         struct pandecode_mapped_memory *umem = pandecode_find_mapped_gpu_mem_containing(pubufs);
-        struct mali_uniform_buffer_meta *PANDECODE_PTR_VAR(ubufs, umem, pubufs);
+        uint64_t *PANDECODE_PTR_VAR(ubufs, umem, pubufs);
 
         for (int i = 0; i < ubufs_count; i++) {
-                unsigned size = (ubufs[i].size + 1) * 16;
-                mali_ptr addr = ubufs[i].ptr << 2;
+                unsigned size = (ubufs[i] & ((1 << 10) - 1)) * 16;
+                mali_ptr addr = (ubufs[i] >> 10) << 2;
 
                 pandecode_validate_buffer(addr, size);
 
-                char *ptr = pointer_as_memory_reference(ubufs[i].ptr << 2);
+                char *ptr = pointer_as_memory_reference(addr);
                 pandecode_log("ubuf_%d[%u] = %s;\n", i, size, ptr);
                 free(ptr);
         }