[PATCH] drm/amd/amdgpu: Add pcie indirect support to amdgpu_mm_wreg_mmio_rlc()

[Alex Deucher]

On Sun, Jan 9, 2022 at 5:27 AM Zhang, Hawking <Hawking.Zhang at amd.com> wrote:
>
> [AMD Official Use Only]
>
> RE - Actually, for older asics, we shouldn't we be using mmINDEX/mmDATA rather than the pcie indirect registers?  Or is that handled already somehow?
>
> I remember we checked this with hw team before (might two years ago when make the change in amdgpu_device_rreg/wreg helper). The answer was it is safe to retire mmINDEX/DATA approach for SI and onwards. PCIE_INDEX/DATA should be good enough for indirect access in amdgpu driver. For radeon driver, mmINDEX/mmDATA shall still be kept.
>

Thanks for the confirmation.

Alex

> Regards,
> Hawking
> -----Original Message-----
> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Alex Deucher
> Sent: Sunday, January 9, 2022 05:13
> To: StDenis, Tom <Tom.StDenis at amd.com>
> Cc: amd-gfx list <amd-gfx at lists.freedesktop.org>
> Subject: Re: [PATCH] drm/amd/amdgpu: Add pcie indirect support to amdgpu_mm_wreg_mmio_rlc()
>
> On Fri, Jan 7, 2022 at 7:07 AM Tom St Denis <tom.stdenis at amd.com> wrote:
> >
> > The function amdgpu_mm_wreg_mmio_rlc() is used by debugfs to write to
> > MMIO registers.  It didn't support registers beyond the BAR mapped
> > MMIO space.  This adds pcie indirect write support.
> >
> > Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
> > ---
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > index c38e0e87090b..53a04095a6db 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > @@ -552,7 +552,7 @@ void amdgpu_device_wreg(struct amdgpu_device
> > *adev,  }
> >
> >  /**
> > - * amdgpu_mm_wreg_mmio_rlc -  write register either with mmio or with
> > RLC path if in range
> > + * amdgpu_mm_wreg_mmio_rlc -  write register either with
> > + direct/indirect mmio or with RLC path if in range
> >   *
> >   * this function is invoked only the debugfs register access
> >   */
> > @@ -567,6 +567,8 @@ void amdgpu_mm_wreg_mmio_rlc(struct amdgpu_device *adev,
> >             adev->gfx.rlc.funcs->is_rlcg_access_range) {
> >                 if (adev->gfx.rlc.funcs->is_rlcg_access_range(adev, reg))
> >                         return adev->gfx.rlc.funcs->sriov_wreg(adev,
> > reg, v, 0, 0);
> > +       } else if ((reg * 4) >= adev->rmmio_size) {
> > +               adev->pcie_wreg(adev, reg * 4, v);
>
> Actually, for older asics, we shouldn't we be using mmINDEX/mmDATA rather than the pcie indirect registers?  Or is that handled already somehow?
>
> Alex
>
> >         } else {
> >                 writel(v, ((void __iomem *)adev->rmmio) + (reg * 4));
> >         }
> > --
> > 2.32.0
> >