Re: [PATCH 7/7] drm/i915: Add non claimed mmio checking for vlv/chv

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 7/7] drm/i915: Add non claimed mmio checking for vlv/chv
Date: Tue, 15 Dec 2015 19:55:11 +0200	[thread overview]
Message-ID: <20151215175511.GN4437@intel.com> (raw)
In-Reply-To: <1450201542-22918-1-git-send-email-mika.kuoppala@intel.com>

On Tue, Dec 15, 2015 at 07:45:42PM +0200, Mika Kuoppala wrote:
> Imre mentioned that chv might also have capability to
> track unclaimed mmio accesses. Ville added that
> both chv and vlv has this capability and he had already
> made this way back [1]. Mimic what Ville's patch does
> but adapt on top of less frequent mmio accesses by
> omitting checking always on reg writes.
> 
> This patch is untested as of now.
> 
> v2: overflow handling and posting omitted (Ville)
> 
> References: [1] http://lists.freedesktop.org/archives/intel-gfx/2013-May/027599.html
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>

lgtm

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/i915_reg.h     |  5 +++++
>  drivers/gpu/drm/i915/intel_uncore.c | 31 +++++++++++++++++++++++++++----
>  2 files changed, 32 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 007ae83..0a98889 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -1711,6 +1711,11 @@ enum skl_disp_power_wells {
>  #define FPGA_DBG		_MMIO(0x42300)
>  #define   FPGA_DBG_RM_NOCLAIM	(1<<31)
>  
> +#define CLAIM_ER		_MMIO(VLV_DISPLAY_BASE + 0x2028)
> +#define   CLAIM_ER_CLR		(1 << 31)
> +#define   CLAIM_ER_OVERFLOW	(1 << 16)
> +#define   CLAIM_ER_CTR_MASK	0xffff
> +
>  #define DERRMR		_MMIO(0x44050)
>  /* Note that HBLANK events are reserved on bdw+ */
>  #define   DERRMR_PIPEA_SCANLINE		(1<<0)
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index b6910eb..61179ae 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -335,13 +335,10 @@ static void intel_uncore_ellc_detect(struct drm_device *dev)
>  }
>  
>  static bool
> -check_for_unclaimed_mmio(struct drm_i915_private *dev_priv)
> +fpga_check_for_unclaimed_mmio(struct drm_i915_private *dev_priv)
>  {
>  	u32 dbg;
>  
> -	if (!HAS_FPGA_DBG_UNCLAIMED(dev_priv))
> -		return false;
> -
>  	dbg = __raw_i915_read32(dev_priv, FPGA_DBG);
>  	if (likely(!(dbg & FPGA_DBG_RM_NOCLAIM)))
>  		return false;
> @@ -351,6 +348,32 @@ check_for_unclaimed_mmio(struct drm_i915_private *dev_priv)
>  	return true;
>  }
>  
> +static bool
> +vlv_check_for_unclaimed_mmio(struct drm_i915_private *dev_priv)
> +{
> +	u32 cer;
> +
> +	cer = __raw_i915_read32(dev_priv, CLAIM_ER);
> +	if (likely(!(cer & (CLAIM_ER_OVERFLOW | CLAIM_ER_CTR_MASK))))
> +		return false;
> +
> +	__raw_i915_write32(dev_priv, CLAIM_ER, CLAIM_ER_CLR);
> +
> +	return true;
> +}
> +
> +static bool
> +check_for_unclaimed_mmio(struct drm_i915_private *dev_priv)
> +{
> +	if (HAS_FPGA_DBG_UNCLAIMED(dev_priv))
> +		return fpga_check_for_unclaimed_mmio(dev_priv);
> +
> +	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> +		return vlv_check_for_unclaimed_mmio(dev_priv);
> +
> +	return false;
> +}
> +
>  static void __intel_uncore_early_sanitize(struct drm_device *dev,
>  					  bool restore_forcewake)
>  {
> -- 
> 2.5.0

-- 
Ville Syrjälä
Intel OTC
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