[Intel-gfx] [PATCH] drm/i915/skl: Update eDRAM calculation

[Jani Nikula]

On Wed, 13 Apr 2016, Ben Widawsky <ben at bwidawsk.net> wrote:
> The two behavioral changes here are the correct detection of the eDRAM size on
> gen9 (SKL + KBL), and unconditional printing of the eLLC size.
>
> Cc: Eero Tamminen <eero.t.tamminen at intel.com>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>

Please see [1].

BR,
Jani.


[1] http://patchwork.freedesktop.org/patch/msgid/1460557604-7126-3-git-send-email-mika.kuoppala@intel.com


> ---
>  drivers/gpu/drm/i915/intel_uncore.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index fbc1d21..efef724 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -314,8 +314,17 @@ static void intel_uncore_ellc_detect(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> -	if ((IS_HASWELL(dev) || IS_BROADWELL(dev) ||
> -	     INTEL_INFO(dev)->gen >= 9) &&
> +	if (INTEL_INFO(dev)->gen >= 9 && HAS_LLC(dev)) {
> +		u32 edramcap = __raw_i915_read32(dev_priv, HSW_EDRAM_PRESENT);
> +		if (edramcap & EDRAM_ENABLED) {
> +			int sets = (edramcap >> 8) & 0x3;
> +			int ways = (edramcap >> 5) & 0x7;
> +			int banks = (edramcap >> 1) & 0xf;
> +
> +			ways = (ways + 1) * 4;
> +			dev_priv->ellc_size = sets * ways * banks;
> +		}
> +	} else if ((IS_HASWELL(dev) || IS_BROADWELL(dev)) &&
>  	    (__raw_i915_read32(dev_priv, HSW_EDRAM_PRESENT) & EDRAM_ENABLED)) {
>  		/* The docs do not explain exactly how the calculation can be
>  		 * made. It is somewhat guessable, but for now, it's always
> @@ -323,8 +332,9 @@ static void intel_uncore_ellc_detect(struct drm_device *dev)
>  		 * NB: We can't write IDICR yet because we do not have gt funcs
>  		 * set up */
>  		dev_priv->ellc_size = 128;
> -		DRM_INFO("Found %zuMB of eLLC\n", dev_priv->ellc_size);
>  	}
> +
> +	DRM_INFO("Found %zuMB of eLLC\n", dev_priv->ellc_size);
>  }
>  
>  static bool

-- 
Jani Nikula, Intel Open Source Technology Center