diff options
| author | Luben Tuikov <luben.tuikov@amd.com> | 2019-10-24 19:30:13 -0400 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2019-12-23 14:55:44 -0500 |
| commit | ce73516d42c9ab011fad498168b892d28e181db4 (patch) | |
| tree | abde0814b6f92ccefa082feb89e9d3b1c9d9dcbc /drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c | |
| parent | f4feb9fa45ee604f44fcc1fb4fb806a0c611acd0 (diff) | |
drm/amdgpu: simplify padding calculations (v2)
Simplify padding calculations.
v2: Comment update and spacing.
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c')
| -rw-r--r-- | drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c b/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c index 1243cfefa2a5..4c6bf1f8a528 100644 --- a/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c +++ b/drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c @@ -382,8 +382,15 @@ static void sdma_v5_0_ring_emit_ib(struct amdgpu_ring *ring, unsigned vmid = AMDGPU_JOB_GET_VMID(job); uint64_t csa_mc_addr = amdgpu_sdma_get_csa_mc_addr(ring, vmid); - /* IB packet must end on a 8 DW boundary */ - sdma_v5_0_ring_insert_nop(ring, (10 - (lower_32_bits(ring->wptr) & 7)) % 8); + /* An IB packet must end on a 8 DW boundary--the next dword + * must be on a 8-dword boundary. Our IB packet below is 6 + * dwords long, thus add x number of NOPs, such that, in + * modular arithmetic, + * wptr + 6 + x = 8k, k >= 0, which in C is, + * (wptr + 6 + x) % 8 = 0. + * The expression below, is a solution of x. + */ + sdma_v5_0_ring_insert_nop(ring, (2 - lower_32_bits(ring->wptr)) & 7); amdgpu_ring_write(ring, SDMA_PKT_HEADER_OP(SDMA_OP_INDIRECT) | SDMA_PKT_INDIRECT_HEADER_VMID(vmid & 0xf)); @@ -1076,10 +1083,10 @@ static void sdma_v5_0_vm_set_pte_pde(struct amdgpu_ib *ib, } /** - * sdma_v5_0_ring_pad_ib - pad the IB to the required number of dw - * + * sdma_v5_0_ring_pad_ib - pad the IB * @ib: indirect buffer to fill with padding * + * Pad the IB with NOPs to a boundary multiple of 8. */ static void sdma_v5_0_ring_pad_ib(struct amdgpu_ring *ring, struct amdgpu_ib *ib) { @@ -1087,7 +1094,7 @@ static void sdma_v5_0_ring_pad_ib(struct amdgpu_ring *ring, struct amdgpu_ib *ib u32 pad_count; int i; - pad_count = (8 - (ib->length_dw & 0x7)) % 8; + pad_count = (-ib->length_dw) & 0x7; for (i = 0; i < pad_count; i++) if (sdma && sdma->burst_nop && (i == 0)) ib->ptr[ib->length_dw++] = |