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

[Christian König]

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.

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 König
> <deathsimple at vodafone.de> wrote:
>> From: Christian König <christian.koenig at amd.com>
>>
>> Try to resize BAR0 to let CPU access all of VRAM.
>>
>> Signed-off-by: Christian König <christian.koenig at amd.com>
>> ---
>>   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
>>
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