Re: [Intel-gfx] [PATCH v2 1/3] drm/i915: Add missing mask when reading GEN12_DSMBASE

[Wayne Boyer <wayne.boyer@intel.com>]

On 9/16/22 10:36 AM, Lucas De Marchi wrote:
> DSMBASE register is defined so BDSM bitfield contains the bits 63 to 20
> of the base address of stolen. For the supported platforms bits 0-19 are
> zero but that may not be true in future. Add the missing mask.
> 
> v2: Use REG_GENMASK64()
> 
> Acked-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
> Reviewed-by: Caz Yokoyama <caz@caztech.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> 

Reviewed-by: Wayne Boyer <wayne.boyer@intel.com>

> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
> index acc561c0f0aa..3665f9b035bb 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
> @@ -814,7 +814,7 @@ i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type,
>   		return ERR_PTR(-ENXIO);
>   
>   	/* Use DSM base address instead for stolen memory */
> -	dsm_base = intel_uncore_read64(uncore, GEN12_DSMBASE);
> +	dsm_base = intel_uncore_read64(uncore, GEN12_DSMBASE) & GEN12_BDSM_MASK;
>   	if (IS_DG1(uncore->i915)) {
>   		lmem_size = pci_resource_len(pdev, GEN12_LMEM_BAR);
>   		if (WARN_ON(lmem_size < dsm_base))
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 1a9bd829fc7e..9584a50ed612 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -7953,6 +7953,7 @@ enum skl_power_gate {
>   
>   #define GEN12_GSMBASE			_MMIO(0x108100)
>   #define GEN12_DSMBASE			_MMIO(0x1080C0)
> +#define   GEN12_BDSM_MASK		REG_GENMASK64(63, 20)
>   
>   #define XEHP_CLOCK_GATE_DIS		_MMIO(0x101014)
>   #define   SGSI_SIDECLK_DIS		REG_BIT(17)
> 

-- 
--
Wayne Boyer
Graphics Software Engineer
VTT-OSGC Platform Enablement