[Mesa-dev] [PATCH 4/4] vc4: Use runtime CPU detection for whether NEON is available.

[Eric Anholt]

This will allow Raspbian's ARMv6 builds to take advantage of the new NEON
code, and could prevent problems if vc4 ends up getting used on a v7 CPU
without NEON.

v2: Drop dead NEON_SUFFIX (noted by Erik Faye-Lund)
---
 src/gallium/drivers/vc4/vc4_screen.c |  3 +++
 src/gallium/drivers/vc4/vc4_tiling.h | 27 +++++++++++++--------------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/src/gallium/drivers/vc4/vc4_screen.c b/src/gallium/drivers/vc4/vc4_screen.c
index b5b1ced49fd5..ce6a9dbaa6cc 100644
--- a/src/gallium/drivers/vc4/vc4_screen.c
+++ b/src/gallium/drivers/vc4/vc4_screen.c
@@ -27,6 +27,7 @@
 #include "pipe/p_screen.h"
 #include "pipe/p_state.h"
 
+#include "util/u_cpu_detect.h"
 #include "util/u_debug.h"
 #include "util/u_memory.h"
 #include "util/u_format.h"
@@ -628,6 +629,8 @@ vc4_screen_create(int fd)
         if (!vc4_get_chip_info(screen))
                 goto fail;
 
+        util_cpu_detect();
+
         slab_create_parent(&screen->transfer_pool, sizeof(struct vc4_transfer), 16);
 
         vc4_fence_init(screen);
diff --git a/src/gallium/drivers/vc4/vc4_tiling.h b/src/gallium/drivers/vc4/vc4_tiling.h
index ba1ad6fb3f7d..3168ec20a606 100644
--- a/src/gallium/drivers/vc4/vc4_tiling.h
+++ b/src/gallium/drivers/vc4/vc4_tiling.h
@@ -27,6 +27,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include "util/macros.h"
+#include "util/u_cpu_detect.h"
 
 /** Return the width in pixels of a 64-byte microtile. */
 static inline uint32_t
@@ -83,23 +84,18 @@ void vc4_store_tiled_image(void *dst, uint32_t dst_stride,
                            uint8_t tiling_format, int cpp,
                            const struct pipe_box *box);
 
-/* If we're building for ARMv7 (Pi 2+), assume it has NEON.  For Raspbian we
- * should extend this to have some runtime detection of being built for ARMv6
- * on a Pi 2+.
- */
-#if defined(__ARM_ARCH) && __ARM_ARCH == 7
-#define NEON_SUFFIX(x) x ## _neon
-#else
-#define NEON_SUFFIX(x) x ## _base
-#endif
-
 static inline void
 vc4_load_lt_image(void *dst, uint32_t dst_stride,
                   void *src, uint32_t src_stride,
                   int cpp, const struct pipe_box *box)
 {
-        NEON_SUFFIX(vc4_load_lt_image)(dst, dst_stride, src, src_stride,
+        if (util_cpu_caps.has_neon) {
+                vc4_load_lt_image_neon(dst, dst_stride, src, src_stride,
                                        cpp, box);
+        } else {
+                vc4_load_lt_image_base(dst, dst_stride, src, src_stride,
+                                       cpp, box);
+        }
 }
 
 static inline void
@@ -107,10 +103,13 @@ vc4_store_lt_image(void *dst, uint32_t dst_stride,
                    void *src, uint32_t src_stride,
                    int cpp, const struct pipe_box *box)
 {
-        NEON_SUFFIX(vc4_store_lt_image)(dst, dst_stride, src, src_stride,
+        if (util_cpu_caps.has_neon) {
+                vc4_store_lt_image_neon(dst, dst_stride, src, src_stride,
                                         cpp, box);
+        } else {
+                vc4_store_lt_image_base(dst, dst_stride, src, src_stride,
+                                        cpp, box);
+        }
 }
 
-#undef NEON_SUFFIX
-
 #endif /* VC4_TILING_H */
-- 
2.11.0