[PATCH 0/4] Ring padding CPU optimisation and some RFC bits

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>

I've noticed the hardware ring padding optimisations have landed so I decided
to respin the CPU side optimisations.

First two patches are simply adding ring fill helpers which deal with reducing
the CPU cost of emitting hundreds of nops from the for-amdgpu_ring_write loops.

If receptive for the idea, please double-check I preserved endianess behaviour
as is.

Last two patches are new and RFC. Both are incomplete conversion to two new
helpers intended to deal with an often repeated pattern of:

-               amdgpu_ring_write(ring, lower_32_bits(addr));
-               amdgpu_ring_write(ring, upper_32_bits(addr));
+               amdgpu_ring_write_addr(ring, addr);

Last patch is the most uncertain one where there seems to be some magic bit
used only on big endian. It has no name so I couldn't figure out what it was
about.

-       amdgpu_ring_write(ring,
-#ifdef __BIG_ENDIAN
-                               (2 << 0) |
-#endif
-                               lower_32_bits(ib->gpu_addr));
-       amdgpu_ring_write(ring, upper_32_bits(ib->gpu_addr));
+       amdgpu_ring_write_addr_xbe(ring, ib->gpu_addr);

Anyway, both patterns have a lot of users so reductions in source code and
binary size aside, main question is do these kind of helpers improve readability
or are making it worse.

(Note that the _xbe name in the last patch is just a placeholder.)

Cc: Christian König <ckoenig.leichtzumerken at gmail.com>
Cc: Sunil Khatri <sunil.khatri at amd.com>

Tvrtko Ursulin (4):
  drm/amdgpu: More efficient ring padding
  drm/amdgpu: More more efficient ring padding
  drm/amdgpu: Add and use amdgpu_ring_write_addr() helper
  drm/amdgpu: Document the magic big endian bit

 drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c |  19 ++++-
 drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h | 101 +++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_vce.c  |   6 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_vpe.c  |  25 +++---
 drivers/gpu/drm/amd/amdgpu/cik_sdma.c    |  27 +++---
 drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c   |  66 +++++----------
 drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c   |  60 +++++---------
 drivers/gpu/drm/amd/amdgpu/gfx_v12_0.c   |  45 ++++------
 drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c    |  63 +++++---------
 drivers/gpu/drm/amd/amdgpu/gfx_v9_4_3.c  |  48 ++++-------
 drivers/gpu/drm/amd/amdgpu/jpeg_v1_0.c   |   8 +-
 drivers/gpu/drm/amd/amdgpu/jpeg_v2_0.c   |   8 +-
 drivers/gpu/drm/amd/amdgpu/jpeg_v4_0_3.c |   8 +-
 drivers/gpu/drm/amd/amdgpu/sdma_v2_4.c   |  16 ++--
 drivers/gpu/drm/amd/amdgpu/sdma_v3_0.c   |  16 ++--
 drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c   |  16 ++--
 drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c |  16 ++--
 drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c   |  16 ++--
 drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c   |  16 ++--
 drivers/gpu/drm/amd/amdgpu/sdma_v6_0.c   |  16 ++--
 drivers/gpu/drm/amd/amdgpu/sdma_v7_0.c   |  16 ++--
 drivers/gpu/drm/amd/amdgpu/uvd_v3_1.c    |   7 +-
 drivers/gpu/drm/amd/amdgpu/uvd_v4_2.c    |   7 +-
 drivers/gpu/drm/amd/amdgpu/uvd_v5_0.c    |   7 +-
 drivers/gpu/drm/amd/amdgpu/uvd_v6_0.c    |   7 +-
 drivers/gpu/drm/amd/amdgpu/uvd_v7_0.c    |   9 +-
 drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c    |   8 +-
 drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c    |   7 +-
 28 files changed, 319 insertions(+), 345 deletions(-)

-- 
2.46.0