[PATCH] drm/amdkfd: On GFX11 check PCIe atomics support and set CP_HQD_HQ_STATUS0[29]

[Russell, Kent]

[AMD Official Use Only - General]

Comments inline

> -----Original Message-----
> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of
> Sreekant Somasekharan
> Sent: Monday, April 3, 2023 3:59 PM
> To: amd-gfx at lists.freedesktop.org
> Cc: Somasekharan, Sreekant <Sreekant.Somasekharan at amd.com>
> Subject: [PATCH] drm/amdkfd: On GFX11 check PCIe atomics support and set
> CP_HQD_HQ_STATUS0[29]
> 
> On GFX11, CP_HQD_HQ_STATUS0[29] bit will be used by CPFW to acknowledge
> whether PCIe atomics are supported. The default value of this bit is set
> to 0. Driver will check whether PCIe atomics are supported and set the
> bit to 1 if supported. This will force CPFW to use real atomic ops.
> If the bit is not set, CPFW will default to read/modify/write using the
> firmware itself.
> 
> This is applicable only to RS64 based GFX11 with MEC FW greater than or
> equal to 509. If MEC FW is less than 509, PCIe atomics needs to be
> supported, else it will skip the device.
> 
> This commit also involves moving amdgpu_amdkfd_device_probe() function
> call after per-IP early_init loop in amdgpu_device_ip_early_init()
> function so as to check for RS64 enabled device.
> 
> Signed-off-by: Sreekant Somasekharan <sreekant.somasekharan at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c       |  2 +-
>  drivers/gpu/drm/amd/amdkfd/kfd_device.c          | 11 +++++++++++
>  drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v11.c |  9 +++++++++
>  3 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 7116119ed038..b3a754ca0923 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -2150,7 +2150,6 @@ static int amdgpu_device_ip_early_init(struct
> amdgpu_device *adev)
>  		adev->has_pr3 = parent ? pci_pr3_present(parent) : false;
>  	}
> 
> -	amdgpu_amdkfd_device_probe(adev);
> 
>  	adev->pm.pp_feature = amdgpu_pp_feature_mask;
>  	if (amdgpu_sriov_vf(adev) || sched_policy ==
> KFD_SCHED_POLICY_NO_HWS)
> @@ -2206,6 +2205,7 @@ static int amdgpu_device_ip_early_init(struct
> amdgpu_device *adev)
>  	if (!total)
>  		return -ENODEV;
> 
> +	amdgpu_amdkfd_device_probe(adev);
>  	adev->cg_flags &= amdgpu_cg_mask;
>  	adev->pg_flags &= amdgpu_pg_mask;
> 
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
> index 521dfa88aad8..64a295a35d37 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
> @@ -204,6 +204,17 @@ static void kfd_device_info_init(struct kfd_dev *kfd,
>  			/* Navi1x+ */
>  			if (gc_version >= IP_VERSION(10, 1, 1))
>  				kfd->device_info.needs_pci_atomics = true;
> +		} else if (gc_version < IP_VERSION(12, 0, 0)) {


What if we get a GFX9 with MEC v509? Wouldn't that trigger this too? Wondering if this should be
if (gc_version>=IP_VERSION(11,0,0) && gc_version < IP_VERSION(12,0,0))
thus ensuring it's only GFX11. Or maybe there is some better check than that. Either way, checking that it's < GFX11 might false-positive on GFX10- too, so we should probably be explicit in our GFX check that it's only GFX11.

 Kent

> +			/* On GFX11 running on RS64, MEC FW version must be
> greater than
> +			 * or equal to version 509 to support acknowledging
> whether
> +			 * PCIe atomics are supported. Before MEC version 509,
> PCIe
> +			 * atomics are required. After that, the FW's use of
> atomics
> +			 * is controlled by CP_HQD_HQ_STATUS0[29].
> +			 * This will fail on GFX11 when PCIe atomics are not
> supported
> +			 * and MEC FW version < 509 for RS64 based CPFW.
> +			 */
> +			kfd->device_info.needs_pci_atomics = true;
> +			kfd->device_info.no_atomic_fw_version = kfd->adev-
> >gfx.rs64_enable ? 509 : 0;
>  		}
>  	} else {
>  		kfd->device_info.doorbell_size = 4;
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v11.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v11.c
> index 4a9af800b1f1..c5ea594abbf6 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v11.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v11.c
> @@ -143,6 +143,15 @@ static void init_mqd(struct mqd_manager *mm, void
> **mqd,
>  			1 << CP_HQD_QUANTUM__QUANTUM_SCALE__SHIFT
> |
>  			1 <<
> CP_HQD_QUANTUM__QUANTUM_DURATION__SHIFT;
> 
> +	/*
> +	 * If PCIe atomics are supported, set CP_HQD_HQ_STATUS0[29] == 1
> +	 * to force CPFW to use atomics. This is supported only on MEC FW
> +	 * version >= 509 and on RS64 based CPFW only. On previous versions,
> +	 * platforms running on GFX11 must support atomics else will skip the
> device.
> +	 */
> +	if (amdgpu_amdkfd_have_atomics_support((mm->dev->adev)))
> +		m->cp_hqd_hq_status0 |= 1 << 29;
> +
>  	if (q->format == KFD_QUEUE_FORMAT_AQL) {
>  		m->cp_hqd_aql_control =
>  			1 << CP_HQD_AQL_CONTROL__CONTROL0__SHIFT;
> --
> 2.25.1