RE: [PATCH 4/4] drm/amdgpu: resize VRAM BAR for CPU access

[Deucher, Alexander]

> -----Original Message-----
> From: amd-gfx [mailto:amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf
> Of Christian KÃnig
> Sent: Wednesday, March 15, 2017 3:38 AM
> To: Ayyappa Ch
> Cc: linux-pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; amd-
> gfx@xxxxxxxxxxxxxxxxxxxxx; platform-driver-x86@xxxxxxxxxxxxxxx;
> helgaas@xxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH 4/4] drm/amdgpu: resize VRAM BAR for CPU access
> 
> Carizzo is an APU and resizing BARs isn't needed nor supported there.
> The CPU can access the full stolen VRAM directly on that hardware.
> 
> As far as I know ASICs with support for this are Tonga, Fiji and all
> Polaris variants.

I think resizable BARs are supported as far back as evergreen or NI.

Alex

> 
> Christian.
> 
> Am 15.03.2017 um 08:23 schrieb Ayyappa Ch:
> > Is it possible on Carrizo asics? Or only supports on newer asics?
> >
> > On Mon, Mar 13, 2017 at 6:11 PM, Christian KÃnig
> > <deathsimple@xxxxxxxxxxx> wrote:
> >> From: Christian KÃnig <christian.koenig@xxxxxxx>
> >>
> >> Try to resize BAR0 to let CPU access all of VRAM.
> >>
> >> Signed-off-by: Christian KÃnig <christian.koenig@xxxxxxx>
> >> ---
> >>   drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  1 +
> >>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 29
> +++++++++++++++++++++++++++++
> >>   drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c      |  8 +++++---
> >>   drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c      |  8 +++++---
> >>   4 files changed, 40 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> >> index 3b81ded..905ded9 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> >> @@ -1719,6 +1719,7 @@ uint64_t amdgpu_ttm_tt_pte_flags(struct
> amdgpu_device *adev, struct ttm_tt *ttm,
> >>                                   struct ttm_mem_reg *mem);
> >>   void amdgpu_vram_location(struct amdgpu_device *adev, struct
> amdgpu_mc *mc, u64 base);
> >>   void amdgpu_gtt_location(struct amdgpu_device *adev, struct
> amdgpu_mc *mc);
> >> +void amdgpu_resize_bar0(struct amdgpu_device *adev);
> >>   void amdgpu_ttm_set_active_vram_size(struct amdgpu_device *adev,
> u64 size);
> >>   int amdgpu_ttm_init(struct amdgpu_device *adev);
> >>   void amdgpu_ttm_fini(struct amdgpu_device *adev);
> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >> index 118f4e6..92955fe 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> >> @@ -692,6 +692,35 @@ void amdgpu_gtt_location(struct amdgpu_device
> *adev, struct amdgpu_mc *mc)
> >>                          mc->gtt_size >> 20, mc->gtt_start, mc->gtt_end);
> >>   }
> >>
> >> +/**
> >> + * amdgpu_resize_bar0 - try to resize BAR0
> >> + *
> >> + * @adev: amdgpu_device pointer
> >> + *
> >> + * Try to resize BAR0 to make all VRAM CPU accessible.
> >> + */
> >> +void amdgpu_resize_bar0(struct amdgpu_device *adev)
> >> +{
> >> +       u32 size = max(ilog2(adev->mc.real_vram_size - 1) + 1, 20) - 20;
> >> +       int r;
> >> +
> >> +       r = pci_resize_resource(adev->pdev, 0, size);
> >> +
> >> +       if (r == -ENOTSUPP) {
> >> +               /* The hardware don't support the extension. */
> >> +               return;
> >> +
> >> +       } else if (r == -ENOSPC) {
> >> +               DRM_INFO("Not enoigh PCI address space for a large BAR.");
> >> +       } else if (r) {
> >> +               DRM_ERROR("Problem resizing BAR0 (%d).", r);
> >> +       }
> >> +
> >> +       /* Reinit the doorbell mapping, it is most likely moved as well */
> >> +       amdgpu_doorbell_fini(adev);
> >> +       BUG_ON(amdgpu_doorbell_init(adev));
> >> +}
> >> +
> >>   /*
> >>    * GPU helpers function.
> >>    */
> >> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> >> index dc9b6d6..36a7aa5 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> >> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> >> @@ -367,13 +367,15 @@ static int gmc_v7_0_mc_init(struct
> amdgpu_device *adev)
> >>                  break;
> >>          }
> >>          adev->mc.vram_width = numchan * chansize;
> >> -       /* Could aper size report 0 ? */
> >> -       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
> >> -       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
> >>          /* size in MB on si */
> >>          adev->mc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) *
> 1024ULL * 1024ULL;
> >>          adev->mc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) *
> 1024ULL * 1024ULL;
> >>
> >> +       if (!(adev->flags & AMD_IS_APU))
> >> +               amdgpu_resize_bar0(adev);
> >> +       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
> >> +       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
> >> +
> >>   #ifdef CONFIG_X86_64
> >>          if (adev->flags & AMD_IS_APU) {
> >>                  adev->mc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET))
> << 22;
> >> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> >> index c087b00..7761ad3 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> >> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> >> @@ -459,13 +459,15 @@ static int gmc_v8_0_mc_init(struct
> amdgpu_device *adev)
> >>                  break;
> >>          }
> >>          adev->mc.vram_width = numchan * chansize;
> >> -       /* Could aper size report 0 ? */
> >> -       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
> >> -       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
> >>          /* size in MB on si */
> >>          adev->mc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) *
> 1024ULL * 1024ULL;
> >>          adev->mc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) *
> 1024ULL * 1024ULL;
> >>
> >> +       if (!(adev->flags & AMD_IS_APU))
> >> +               amdgpu_resize_bar0(adev);
> >> +       adev->mc.aper_base = pci_resource_start(adev->pdev, 0);
> >> +       adev->mc.aper_size = pci_resource_len(adev->pdev, 0);
> >> +
> >>   #ifdef CONFIG_X86_64
> >>          if (adev->flags & AMD_IS_APU) {
> >>                  adev->mc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET))
> << 22;
> >> --
> >> 2.7.4
> >>
> >> _______________________________________________
> >> dri-devel mailing list
> >> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> >> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
> 
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