[PATCH] drm/amdgpu: keep init xcc0 for all xccs under sriov

[Chang, HaiJun]

[AMD Official Use Only - AMD Internal Distribution Only]

Hi Lijo,

Right, 18bits are byte aligned range of local XCC register, 16bites are dword aligned offset range

We find the normalization needs to be applied to many functions, like

  *   KIQ: amdgpu_kiq_r/wreg/
  *   RLC: amdgpu_virt_rlcg_reg_rw
  *   KIQ: amdgpu_gmc_fw_reg_write_reg_wait
  *   KIQ: amdgpu_ring_emit_reg_write_reg_wait/amdgpu_ring_emit_reg_wait/amdgpu_ring_emit_wreg

For sriov gfx register access, it only has 2 ways: rlc or kiq.  Both of the ways can use local xcc offset,  so we think it's simpler change to init the gfx register offsets with local xcc offset only.

Thanks,
HaiJun

From: Lazar, Lijo <Lijo.Lazar at amd.com>
Sent: Saturday, June 15, 2024 10:09 AM
To: Jian, Jane <Jane.Jian at amd.com>; Chang, HaiJun <HaiJun.Chang at amd.com>; Zhao, Victor <Victor.Zhao at amd.com>
Cc: amd-gfx at lists.freedesktop.org
Subject: Re: [PATCH] drm/amdgpu: keep init xcc0 for all xccs under sriov


[AMD Official Use Only - AMD Internal Distribution Only]

Never mind, bit 16 and above is probably because of dword aligned offset.

Any reason not to do this in kiq/rlc based writes to normalise all?

Thanks,
Lijo
________________________________
From: Lazar, Lijo
Sent: Friday, June 14, 2024 5:20:30 PM
To: Jian, Jane <Jane.Jian at amd.com<mailto:Jane.Jian at amd.com>>; Chang, HaiJun <HaiJun.Chang at amd.com<mailto:HaiJun.Chang at amd.com>>; Zhao, Victor <Victor.Zhao at amd.com<mailto:Victor.Zhao at amd.com>>
Cc: amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org> <amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>>
Subject: Re: [PATCH] drm/amdgpu: keep init xcc0 for all xccs under sriov



On 6/14/2024 4:40 PM, Jane Jian wrote:
> [WHY]
> sriov has the higher bit violation when flushing tlb
>
> [HOW]
> for sriov only init XCC0(lower 16-bit) for all XCCs to avoid higher bit violation
> since kiq ring is always local, local address without XCC ID is enough to be sent to the XCC KIQ
>

The description is incorrect.

Bits 18:20 represent xcc id. To guarantee all paths pass a local
address, you should just strip bits 18:20 in kiq/rlcg read/write
functions rather than here.

Thanks,
Lijo

> Signed-off-by: Jane Jian <Jane.Jian at amd.com<mailto:Jane.Jian at amd.com>>
> ---
>  drivers/gpu/drm/amd/amdgpu/gfxhub_v1_2.c | 23 +++++++++++++++--------
>  1 file changed, 15 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_2.c b/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_2.c
> index e14acab5cceb..4e38a66a52f4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_2.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_2.c
> @@ -537,29 +537,36 @@ static void gfxhub_v1_2_xcc_init(struct amdgpu_device *adev, uint32_t xcc_mask)
>  {
>        struct amdgpu_vmhub *hub;
>        int i;
> +     uint32_t gc_index;
>
>        for_each_inst(i, xcc_mask) {
>                hub = &adev->vmhub[AMDGPU_GFXHUB(i)];
>
> +             /* for sriov only init XCC0(lower 16-bit) to avoid higher bit violation */
> +             if (amdgpu_sriov_vf(adev))
> +                     gc_index = 0;
> +             else
> +                     gc_index = GET_INST(GC, i);
> +
>                hub->ctx0_ptb_addr_lo32 =
> -                     SOC15_REG_OFFSET(GC, GET_INST(GC, i),
> +                     SOC15_REG_OFFSET(GC, gc_index,
>                                regVM_CONTEXT0_PAGE_TABLE_BASE_ADDR_LO32);
>                hub->ctx0_ptb_addr_hi32 =
> -                     SOC15_REG_OFFSET(GC, GET_INST(GC, i),
> +                     SOC15_REG_OFFSET(GC, gc_index,
>                                regVM_CONTEXT0_PAGE_TABLE_BASE_ADDR_HI32);
>                hub->vm_inv_eng0_sem =
> -                     SOC15_REG_OFFSET(GC, GET_INST(GC, i), regVM_INVALIDATE_ENG0_SEM);
> +                     SOC15_REG_OFFSET(GC, gc_index, regVM_INVALIDATE_ENG0_SEM);
>                hub->vm_inv_eng0_req =
> -                     SOC15_REG_OFFSET(GC, GET_INST(GC, i), regVM_INVALIDATE_ENG0_REQ);
> +                     SOC15_REG_OFFSET(GC, gc_index, regVM_INVALIDATE_ENG0_REQ);
>                hub->vm_inv_eng0_ack =
> -                     SOC15_REG_OFFSET(GC, GET_INST(GC, i), regVM_INVALIDATE_ENG0_ACK);
> +                     SOC15_REG_OFFSET(GC, gc_index, regVM_INVALIDATE_ENG0_ACK);
>                hub->vm_context0_cntl =
> -                     SOC15_REG_OFFSET(GC, GET_INST(GC, i), regVM_CONTEXT0_CNTL);
> +                     SOC15_REG_OFFSET(GC, gc_index, regVM_CONTEXT0_CNTL);
>                hub->vm_l2_pro_fault_status =
> -                     SOC15_REG_OFFSET(GC, GET_INST(GC, i),
> +                     SOC15_REG_OFFSET(GC, gc_index,
>                                regVM_L2_PROTECTION_FAULT_STATUS);
>                hub->vm_l2_pro_fault_cntl =
> -                     SOC15_REG_OFFSET(GC, GET_INST(GC, i), regVM_L2_PROTECTION_FAULT_CNTL);
> +                     SOC15_REG_OFFSET(GC, gc_index, regVM_L2_PROTECTION_FAULT_CNTL);
>
>                hub->ctx_distance = regVM_CONTEXT1_CNTL -
>                                regVM_CONTEXT0_CNTL;
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