RE: [PATCH] drm/amdgpu: Fix sdma 4.4.2 doorbell rptr/wptr init

["Kamal, Asad" <Asad.Kamal@xxxxxxx>]

[AMD Official Use Only - General]

Reviewed-by: Asad Kamal <asad.kamal@xxxxxxx>
Tested-by: Asad Kamal <asad.kamal@xxxxxxx>

Thanks & Regards
Asad

-----Original Message-----
From: Lazar, Lijo <Lijo.Lazar@xxxxxxx>
Sent: Monday, November 6, 2023 9:51 AM
To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Zhang, Hawking <Hawking.Zhang@xxxxxxx>; Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Kamal, Asad <Asad.Kamal@xxxxxxx>; Ma, Le <Le.Ma@xxxxxxx>
Subject: [PATCH] drm/amdgpu: Fix sdma 4.4.2 doorbell rptr/wptr init

Doorbell rptr/wptr can be set through multiple ways including direct register initialization. Disable doorbell during hw_fini once the ring is disabled so that during next module reload direct initialization takes effect. Also, move the direct initialization after minor update is set to 1 since rptr/wptr are reinitialized back to 0 which could be lower than the previous doorbell value (ex: cases like module reload).

Signed-off-by: Lijo Lazar <lijo.lazar@xxxxxxx>
---
 drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c | 25 ++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c b/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c
index c46bc6aa4f48..bd65a62f8903 100644
--- a/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c
+++ b/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c
@@ -427,6 +427,7 @@ static void sdma_v4_4_2_inst_gfx_stop(struct amdgpu_device *adev,
                                      uint32_t inst_mask)
 {
        struct amdgpu_ring *sdma[AMDGPU_MAX_SDMA_INSTANCES];
+       u32 doorbell_offset, doorbell;
        u32 rb_cntl, ib_cntl;
        int i, unset = 0;

@@ -444,6 +445,18 @@ static void sdma_v4_4_2_inst_gfx_stop(struct amdgpu_device *adev,
                ib_cntl = RREG32_SDMA(i, regSDMA_GFX_IB_CNTL);
                ib_cntl = REG_SET_FIELD(ib_cntl, SDMA_GFX_IB_CNTL, IB_ENABLE, 0);
                WREG32_SDMA(i, regSDMA_GFX_IB_CNTL, ib_cntl);
+
+               if (sdma[i]->use_doorbell) {
+                       doorbell = RREG32_SDMA(i, regSDMA_GFX_DOORBELL);
+                       doorbell_offset = RREG32_SDMA(i, regSDMA_GFX_DOORBELL_OFFSET);
+
+                       doorbell = REG_SET_FIELD(doorbell, SDMA_GFX_DOORBELL, ENABLE, 0);
+                       doorbell_offset = REG_SET_FIELD(doorbell_offset,
+                                       SDMA_GFX_DOORBELL_OFFSET,
+                                       OFFSET, 0);
+                       WREG32_SDMA(i, regSDMA_GFX_DOORBELL, doorbell);
+                       WREG32_SDMA(i, regSDMA_GFX_DOORBELL_OFFSET, doorbell_offset);
+               }
        }
 }

@@ -631,12 +644,6 @@ static void sdma_v4_4_2_gfx_resume(struct amdgpu_device *adev, unsigned int i)
        rb_cntl = sdma_v4_4_2_rb_cntl(ring, rb_cntl);
        WREG32_SDMA(i, regSDMA_GFX_RB_CNTL, rb_cntl);

-       /* Initialize the ring buffer's read and write pointers */
-       WREG32_SDMA(i, regSDMA_GFX_RB_RPTR, 0);
-       WREG32_SDMA(i, regSDMA_GFX_RB_RPTR_HI, 0);
-       WREG32_SDMA(i, regSDMA_GFX_RB_WPTR, 0);
-       WREG32_SDMA(i, regSDMA_GFX_RB_WPTR_HI, 0);
-
        /* set the wb address whether it's enabled or not */
        WREG32_SDMA(i, regSDMA_GFX_RB_RPTR_ADDR_HI,
               upper_32_bits(adev->wb.gpu_addr + wb_offset) & 0xFFFFFFFF); @@ -654,6 +661,12 @@ static void sdma_v4_4_2_gfx_resume(struct amdgpu_device *adev, unsigned int i)
        /* before programing wptr to a less value, need set minor_ptr_update first */
        WREG32_SDMA(i, regSDMA_GFX_MINOR_PTR_UPDATE, 1);

+       /* Initialize the ring buffer's read and write pointers */
+       WREG32_SDMA(i, regSDMA_GFX_RB_RPTR, 0);
+       WREG32_SDMA(i, regSDMA_GFX_RB_RPTR_HI, 0);
+       WREG32_SDMA(i, regSDMA_GFX_RB_WPTR, 0);
+       WREG32_SDMA(i, regSDMA_GFX_RB_WPTR_HI, 0);
+
        doorbell = RREG32_SDMA(i, regSDMA_GFX_DOORBELL);
        doorbell_offset = RREG32_SDMA(i, regSDMA_GFX_DOORBELL_OFFSET);

--
2.25.1