On 5/4/25 23:47, Rodrigo Siqueira wrote: > In the GFX code, there are multiple parsers of the CSB buffer, which can > be avoided. This data is parsed via get_csb_buffer() in earlier stages, > and the result can be checked in "adev->gfx.rlc.cs_ptr". To avoid > re-parser the CSB buffer, this commit introduces a helper that copies > the CSB buffer into the ring buffer. > > Signed-off-by: Rodrigo Siqueira <sique...@igalia.com> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c | 21 +++++++++++++++++++++ > drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h | 4 ++++ > 2 files changed, 25 insertions(+) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c > b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c > index 8f1a2f7b03c1..dfd48670a0bf 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c > @@ -2323,6 +2323,27 @@ void amdgpu_gfx_csb_preamble_end(volatile u32 *buffer, > u32 count) > buffer[count++] = cpu_to_le32(0); > } > > +/** > + * amdgpu_gfx_write_csb_to_ring - Write the CSB buffer into the ring > + * > + * @ring: Ring reference. > + * @csb_buffer: CSB buffer. > + * @csb_size: CSB buffer size. > + * > + * Usually, the adev->gfx.rlc.cs_ptr field is filled in earlier stages via > + * get_csb_buffer(). This function just gets the CSB buffer and fills it in > the > + * ring buffer. > + */ > +void amdgpu_gfx_write_csb_to_ring(struct amdgpu_ring *ring,
We already have the amdgpu_ring_write_multiple() function for exactly that. > + volatile u32 *csb_buffer, Please drop volatile from all pointers inside the kernel and point me out if you still find some in existing code. They are nearly always used incorrectly, see here https://docs.kernel.org/process/volatile-considered-harmful.html Thanks, Christian. > + u32 csb_size) > +{ > + int i; > + > + for (i = 0; i < csb_size; i++) > + amdgpu_ring_write(ring, csb_buffer[i]); > +} > + > /* > * debugfs for to enable/disable gfx job submission to specific core. > */ > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h > b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h > index 08f268dab8f5..ce684c3d3d89 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.h > @@ -646,6 +646,10 @@ u32 amdgpu_gfx_csb_preamble_start(volatile u32 *buffer); > u32 amdgpu_gfx_csb_data_parser(struct amdgpu_device *adev, volatile u32 > *buffer, u32 count); > void amdgpu_gfx_csb_preamble_end(volatile u32 *buffer, u32 count); > > +void amdgpu_gfx_write_csb_to_ring(struct amdgpu_ring *ring, > + volatile u32 *csb_buffer, > + u32 csb_size); > + > void amdgpu_debugfs_gfx_sched_mask_init(struct amdgpu_device *adev); > void amdgpu_debugfs_compute_sched_mask_init(struct amdgpu_device *adev); >
