Re: [PATCH] drm/amdgpu: Add memory vendor information

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

On 8/11/2023 12:36 PM, Chen, Guchun wrote:
> [Public]
>
> > -----Original Message-----
> > From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Lijo
> > Lazar
> > Sent: Friday, August 11, 2023 12:12 PM
> > To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> > Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Zhang, Hawking
> > <Hawking.Zhang@xxxxxxx>
> > Subject: [PATCH] drm/amdgpu: Add memory vendor information
> >
> > For ASICs with GC v9.4.3, determine the vendor information from scratch
> > register.
> >
> > Signed-off-by: Lijo Lazar <lijo.lazar@xxxxxxx>
> > Reviewed-by: Hawking Zhang <Hawking.Zhang@xxxxxxx>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 26 ++++++++++++++++++-------
> > -
> >   1 file changed, 18 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> > b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> > index 880460cd3239..f9a5a2c0573e 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> > @@ -1998,6 +1998,19 @@ static int gmc_v9_0_init_mem_ranges(struct
> > amdgpu_device *adev)
> >        return 0;
> >   }
> >
> > +static void gmc_v9_4_3_init_vram_info(struct amdgpu_device *adev) {
> > +     static const u32 regBIF_BIOS_SCRATCH_4 = 0x50;
>
> Any reason to use a static variable here?

It's only done to initialize once and keep it shared even if multiple 
devices use the code path - that will remain true for any reg address I 
guess.

Thanks,
Lijo

> Regards,
> Guchun
>
> > +     u32 vram_info;
> > +
> > +     if (!amdgpu_sriov_vf(adev)) {
> > +             vram_info = RREG32(regBIF_BIOS_SCRATCH_4);
> > +             adev->gmc.vram_vendor = vram_info & 0xF;
> > +     }
> > +     adev->gmc.vram_type = AMDGPU_VRAM_TYPE_HBM;
> > +     adev->gmc.vram_width = 128 * 64;
> > +}
> > +
> >   static int gmc_v9_0_sw_init(void *handle)  {
> >        int r, vram_width = 0, vram_type = 0, vram_vendor = 0,
> > dma_addr_bits; @@ -2010,15 +2023,12 @@ static int
> > gmc_v9_0_sw_init(void *handle)
> >
> >        spin_lock_init(&adev->gmc.invalidate_lock);
> >
> > -     if (!(adev->bios) || adev->gmc.is_app_apu) {
> > +     if (adev->ip_versions[GC_HWIP][0] == IP_VERSION(9, 4, 3)) {
> > +             gmc_v9_4_3_init_vram_info(adev);
> > +     } else if (!adev->bios) {
> >                if (adev->flags & AMD_IS_APU) {
> > -                     if (adev->gmc.is_app_apu) {
> > -                             adev->gmc.vram_type =
> > AMDGPU_VRAM_TYPE_HBM;
> > -                             adev->gmc.vram_width = 128 * 64;
> > -                     } else {
> > -                             adev->gmc.vram_type =
> > AMDGPU_VRAM_TYPE_DDR4;
> > -                             adev->gmc.vram_width = 64 * 64;
> > -                     }
> > +                     adev->gmc.vram_type =
> > AMDGPU_VRAM_TYPE_DDR4;
> > +                     adev->gmc.vram_width = 64 * 64;
> >                } else {
> >                        adev->gmc.vram_type = AMDGPU_VRAM_TYPE_HBM;
> >                        adev->gmc.vram_width = 128 * 64;
> > --
> > 2.25.1