Re: [PATCH v2 1/2] drm/amdgpu: Move HDP remapping earlier during init

["Lazar, Lijo" <lijo.lazar@xxxxxxx>]

On 8/30/2022 8:39 PM, Alex Deucher wrote:
> On Tue, Aug 30, 2022 at 10:45 AM Lazar, Lijo <lijo.lazar@xxxxxxx> wrote:
> > On 8/30/2022 7:18 PM, Alex Deucher wrote:
> > > On Tue, Aug 30, 2022 at 12:05 AM Lazar, Lijo <lijo.lazar@xxxxxxx> wrote:
> > > > On 8/29/2022 10:20 PM, Alex Deucher wrote:
> > > > > On Mon, Aug 29, 2022 at 4:18 AM Lijo Lazar <lijo.lazar@xxxxxxx> wrote:
> > > > > > HDP flush is used early in the init sequence as part of memory controller
> > > > > > block initialization. Hence remapping of HDP registers needed for flush
> > > > > > needs to happen earlier.
> > > > > >
> > > > > > This also fixes the Unsupported Request error reported through AER during
> > > > > > driver load. The error happens as a write happens to the remap offset
> > > > > > before real remapping is done.
> > > > > >
> > > > > > Link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.kernel.org%2Fshow_bug.cgi%3Fid%3D216373&amp;data=05%7C01%7Clijo.lazar%40amd.com%7Cbe8781fe1b0c41d3bad408da8a99b3d8%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637974690005710507%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=98WWFEcwi2tzyf%2BxnYC%2FK3UcCE5mfXI00qfYGUpt2Sk%3D&amp;reserved=0
> > > > > >
> > > > > > The error was unnoticed before and got visible because of the commit
> > > > > > referenced below. This doesn't fix anything in the commit below, rather
> > > > > > fixes the issue in amdgpu exposed by the commit. The reference is only
> > > > > > to associate this commit with below one so that both go together.
> > > > > >
> > > > > > Fixes: 8795e182b02d ("PCI/portdrv: Don't disable AER reporting in get_port_device_capability()")
> > > > > >
> > > > > > Reported-by: Tom Seewald <tseewald@xxxxxxxxx>
> > > > > > Signed-off-by: Lijo Lazar <lijo.lazar@xxxxxxx>
> > > > > > Cc: stable@xxxxxxxxxxxxxxx
> > > > >
> > > > > How about something like the attached patch rather than these two
> > > > > patches?  It's a bit bigger but seems cleaner and more defensive in my
> > > > > opinion.
> > > >
> > > > Whenever device goes to suspend/reset and then comes back, remap offset
> > > > has to be set back to 0 to make sure it doesn't use the wrong offset
> > > > when the register assumes default values again.
> > > >
> > > > To avoid the if-check in hdp_flush (which is more frequent), another way
> > > > is to initialize the remap offset to default offset during early init
> > > > and hw fini/suspend sequences. It won't be obvious (even with this
> > > > patch) as to when remap offset vs default offset is used though.
> > >
> > > On resume, the common IP is resumed first so it will always be set.
> > > The only case that is a problem is init because we init GMC out of
> > > order.  We could init common before GMC in amdgpu_device_ip_init().  I
> > > think that should be fine, but I wasn't sure if there might be some
> > > fallout from that on certain cards.
> >
> > There are other places where an IP order is forced like in
> > amdgpu_device_ip_reinit_early_sriov(). This also may not affect this
> > case as remapping is not done for VF.
> >
> > Agree that a better way is to have the common IP to be inited first.
>
> How about these patches?

Looks good to me. BTW, is nbio 7.7 for an APU (in which case hdp flush 
is not expected to be used)?

Thanks,
Lijo

> Alex
>
>
> > Thanks,
> > Lijo
> >
> > > Alex
> > >
> > > > Thanks,
> > > > Lijo
> > > >
> > > > > Alex
> > > > >
> > > > > > ---
> > > > > > v2:
> > > > > >            Take care of IP resume cases (Alex Deucher)
> > > > > >            Add NULL check to nbio.funcs to cover older (GFXv8) ASICs (Felix Kuehling)
> > > > > >            Add more details in commit message and associate with AER patch (Bjorn
> > > > > > Helgaas)
> > > > > >
> > > > > >     drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 24 ++++++++++++++++++++++
> > > > > >     drivers/gpu/drm/amd/amdgpu/nv.c            |  6 ------
> > > > > >     drivers/gpu/drm/amd/amdgpu/soc15.c         |  6 ------
> > > > > >     drivers/gpu/drm/amd/amdgpu/soc21.c         |  6 ------
> > > > > >     4 files changed, 24 insertions(+), 18 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > > > > > index ce7d117efdb5..e420118769a5 100644
> > > > > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > > > > > @@ -2334,6 +2334,26 @@ static int amdgpu_device_init_schedulers(struct amdgpu_device *adev)
> > > > > >            return 0;
> > > > > >     }
> > > > > >
> > > > > > +/**
> > > > > > + * amdgpu_device_prepare_ip - prepare IPs for hardware initialization
> > > > > > + *
> > > > > > + * @adev: amdgpu_device pointer
> > > > > > + *
> > > > > > + * Any common hardware initialization sequence that needs to be done before
> > > > > > + * hw init of individual IPs is performed here. This is different from the
> > > > > > + * 'common block' which initializes a set of IPs.
> > > > > > + */
> > > > > > +static void amdgpu_device_prepare_ip(struct amdgpu_device *adev)
> > > > > > +{
> > > > > > +       /* Remap HDP registers to a hole in mmio space, for the purpose
> > > > > > +        * of exposing those registers to process space. This needs to be
> > > > > > +        * done before hw init of ip blocks to take care of HDP flush
> > > > > > +        * operations through registers during hw_init.
> > > > > > +        */
> > > > > > +       if (adev->nbio.funcs && adev->nbio.funcs->remap_hdp_registers &&
> > > > > > +           !amdgpu_sriov_vf(adev))
> > > > > > +               adev->nbio.funcs->remap_hdp_registers(adev);
> > > > > > +}
> > > > > >
> > > > > >     /**
> > > > > >      * amdgpu_device_ip_init - run init for hardware IPs
> > > > > > @@ -2376,6 +2396,8 @@ static int amdgpu_device_ip_init(struct amdgpu_device *adev)
> > > > > >                                    DRM_ERROR("amdgpu_vram_scratch_init failed %d\n", r);
> > > > > >                                    goto init_failed;
> > > > > >                            }
> > > > > > +
> > > > > > +                       amdgpu_device_prepare_ip(adev);
> > > > > >                            r = adev->ip_blocks[i].version->funcs->hw_init((void *)adev);
> > > > > >                            if (r) {
> > > > > >                                    DRM_ERROR("hw_init %d failed %d\n", i, r);
> > > > > > @@ -3058,6 +3080,7 @@ static int amdgpu_device_ip_reinit_early_sriov(struct amdgpu_device *adev)
> > > > > >                    AMD_IP_BLOCK_TYPE_IH,
> > > > > >            };
> > > > > >
> > > > > > +       amdgpu_device_prepare_ip(adev);
> > > > > >            for (i = 0; i < adev->num_ip_blocks; i++) {
> > > > > >                    int j;
> > > > > >                    struct amdgpu_ip_block *block;
> > > > > > @@ -3139,6 +3162,7 @@ static int amdgpu_device_ip_resume_phase1(struct amdgpu_device *adev)
> > > > > >     {
> > > > > >            int i, r;
> > > > > >
> > > > > > +       amdgpu_device_prepare_ip(adev);
> > > > > >            for (i = 0; i < adev->num_ip_blocks; i++) {
> > > > > >                    if (!adev->ip_blocks[i].status.valid || adev->ip_blocks[i].status.hw)
> > > > > >                            continue;
> > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/nv.c b/drivers/gpu/drm/amd/amdgpu/nv.c
> > > > > > index b3fba8dea63c..3ac7fef74277 100644
> > > > > > --- a/drivers/gpu/drm/amd/amdgpu/nv.c
> > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/nv.c
> > > > > > @@ -1032,12 +1032,6 @@ static int nv_common_hw_init(void *handle)
> > > > > >            nv_program_aspm(adev);
> > > > > >            /* setup nbio registers */
> > > > > >            adev->nbio.funcs->init_registers(adev);
> > > > > > -       /* remap HDP registers to a hole in mmio space,
> > > > > > -        * for the purpose of expose those registers
> > > > > > -        * to process space
> > > > > > -        */
> > > > > > -       if (adev->nbio.funcs->remap_hdp_registers && !amdgpu_sriov_vf(adev))
> > > > > > -               adev->nbio.funcs->remap_hdp_registers(adev);
> > > > > >            /* enable the doorbell aperture */
> > > > > >            nv_enable_doorbell_aperture(adev, true);
> > > > > >
> > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/soc15.c b/drivers/gpu/drm/amd/amdgpu/soc15.c
> > > > > > index fde6154f2009..a0481e37d7cf 100644
> > > > > > --- a/drivers/gpu/drm/amd/amdgpu/soc15.c
> > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/soc15.c
> > > > > > @@ -1240,12 +1240,6 @@ static int soc15_common_hw_init(void *handle)
> > > > > >            soc15_program_aspm(adev);
> > > > > >            /* setup nbio registers */
> > > > > >            adev->nbio.funcs->init_registers(adev);
> > > > > > -       /* remap HDP registers to a hole in mmio space,
> > > > > > -        * for the purpose of expose those registers
> > > > > > -        * to process space
> > > > > > -        */
> > > > > > -       if (adev->nbio.funcs->remap_hdp_registers && !amdgpu_sriov_vf(adev))
> > > > > > -               adev->nbio.funcs->remap_hdp_registers(adev);
> > > > > >
> > > > > >            /* enable the doorbell aperture */
> > > > > >            soc15_enable_doorbell_aperture(adev, true);
> > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/soc21.c b/drivers/gpu/drm/amd/amdgpu/soc21.c
> > > > > > index 55284b24f113..16b447055102 100644
> > > > > > --- a/drivers/gpu/drm/amd/amdgpu/soc21.c
> > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/soc21.c
> > > > > > @@ -660,12 +660,6 @@ static int soc21_common_hw_init(void *handle)
> > > > > >            soc21_program_aspm(adev);
> > > > > >            /* setup nbio registers */
> > > > > >            adev->nbio.funcs->init_registers(adev);
> > > > > > -       /* remap HDP registers to a hole in mmio space,
> > > > > > -        * for the purpose of expose those registers
> > > > > > -        * to process space
> > > > > > -        */
> > > > > > -       if (adev->nbio.funcs->remap_hdp_registers)
> > > > > > -               adev->nbio.funcs->remap_hdp_registers(adev);
> > > > > >            /* enable the doorbell aperture */
> > > > > >            soc21_enable_doorbell_aperture(adev, true);
> > > > > >
> > > > > > --
> > > > > > 2.25.1