Re: [PATCH 03/10] drm/i915/chv: Enable Render Standby (RC6) for Cheeryview

[Ben Widawsky <ben@bwidawsk.net>]

On Mon, Apr 21, 2014 at 01:34:07PM +0530, deepak.s@linux.intel.com wrote:
> From: Deepak S <deepak.s@linux.intel.com>
> 
> v2: Configure PCBR if BIOS fails allocate pcbr (deepak)
> 
> v3: Fix PCBR condition check during CHV RC6 Enable flag set
> 
> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h |   1 +
>  drivers/gpu/drm/i915/intel_pm.c | 100 +++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 99 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index b951d61..7090b42 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5134,6 +5134,7 @@ enum punit_power_well {
>  #define GEN6_GT_GFX_RC6				0x138108
>  #define GEN6_GT_GFX_RC6p			0x13810C
>  #define GEN6_GT_GFX_RC6pp			0x138110
> +#define VLV_PCBR_ADDR_SHIFT			12
>  
>  #define GEN6_PCODE_MAILBOX			0x138124
>  #define   GEN6_PCODE_READY			(1<<31)
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index f3c5bce..421a4cc 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3264,6 +3264,18 @@ static void gen6_disable_rps(struct drm_device *dev)
>  		gen6_disable_rps_interrupts(dev);
>  }
>  
> +static void cherryview_disable_rps(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +
> +	I915_WRITE(GEN6_RC_CONTROL, 0);
> +
> +	if (dev_priv->vlv_pctx) {
> +		drm_gem_object_unreference(&dev_priv->vlv_pctx->base);
> +		dev_priv->vlv_pctx = NULL;
> +	}
> +}
> +
>  static void valleyview_disable_rps(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -3642,6 +3654,28 @@ static void valleyview_check_pctx(struct drm_i915_private *dev_priv)
>  			     dev_priv->vlv_pctx->stolen->start);
>  }
>  
> +static void cherryview_setup_pctx(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	unsigned long pctx_paddr;
> +	struct i915_gtt *gtt = &dev_priv->gtt;
> +	u32 pcbr;
> +	int pctx_size = 32*1024;
> +
> +	pcbr = I915_READ(VLV_PCBR);
> +	if ((pcbr >> VLV_PCBR_ADDR_SHIFT) == 0) {
> +		/*
> +		 * From the Gunit register HAS:
> +		 * The Gfx driver is expected to program this register and ensure
> +		 * proper allocation within Gfx stolen memory.  For example, this
> +		 * register should be programmed such than the PCBR range does not
> +		 * overlap with other relevant ranges.
> +		 */
> +		pctx_paddr = (dev_priv->mm.stolen_base + gtt->stolen_size - pctx_size);
> +		I915_WRITE(VLV_PCBR, pctx_paddr);
> +	}
> +}
> +

Is there a reason we did not follow the same idioms as Valleyview?
Shouldn't we be building a stolen object like we do there, and then
using that?

Furthermore, we need to make sure we make the stolen allocator aware for
the case where pcbr is not zero, like we do for valleyview.

I think the best solution here is to try to combine the valleyview and
cherryview logic for this function. Extract out size, and most of the
rest looks pretty similar.

For enabling, I am fine with it as is though provided it's hidden by
preliminary flag.

>  static void valleyview_setup_pctx(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -3697,6 +3731,61 @@ static void valleyview_cleanup_pctx(struct drm_device *dev)
>  	dev_priv->vlv_pctx = NULL;
>  }
>  
> +static void cherryview_enable_rps(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_ring_buffer *ring;
> +	u32 gtfifodbg, rc6_mode = 0, pcbr;
> +	int i;
> +
> +	WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
> +
> +	if ((gtfifodbg = I915_READ(GTFIFODBG))) {
> +		DRM_DEBUG_DRIVER("GT fifo had a previous error %x\n",
> +				 gtfifodbg);
> +		I915_WRITE(GTFIFODBG, gtfifodbg);
> +	}
> +
> +	cherryview_setup_pctx(dev);
> +
> +	/* 1a & 1b: Get forcewake during program sequence. Although the driver
> +	 * hasn't enabled a state yet where we need forcewake, BIOS may have.*/
> +	gen6_gt_force_wake_get(dev_priv, FORCEWAKE_ALL);
> +
> +	/* 2a: Program RC6 thresholds.*/
> +	I915_WRITE(GEN6_RC6_WAKE_RATE_LIMIT, 40 << 16);
> +	I915_WRITE(GEN6_RC_EVALUATION_INTERVAL, 125000); /* 12500 * 1280ns */
> +	I915_WRITE(GEN6_RC_IDLE_HYSTERSIS, 25); /* 25 * 1280ns */
> +
> +	for_each_ring(ring, dev_priv, i)
> +		I915_WRITE(RING_MAX_IDLE(ring->mmio_base), 10);
> +
> +	I915_WRITE(GEN6_RC6_THRESHOLD, 50000); /* 50/125ms per EI */
> +
> +	/* allows RC6 residency counter to work */
> +	I915_WRITE(VLV_COUNTER_CONTROL,
> +		   _MASKED_BIT_ENABLE(VLV_COUNT_RANGE_HIGH |
> +				      VLV_MEDIA_RC6_COUNT_EN |
> +				      VLV_RENDER_RC6_COUNT_EN));
> +
> +	/* Todo: If BIOS has not configured PCBR
> +	 *       then allocate in BIOS Reserved */
> +
> +	/* For now we assume BIOS is allocating and populating the PCBR  */
> +	pcbr = I915_READ(VLV_PCBR);
> +
> +	DRM_DEBUG_DRIVER("PCBR offset : 0x%x\n", pcbr);
> +
> +	/* 3: Enable RC6 */
> +	if ((intel_enable_rc6(dev) & INTEL_RC6_ENABLE) &&
> +						(pcbr >> VLV_PCBR_ADDR_SHIFT))
> +		rc6_mode = GEN6_RC_CTL_EI_MODE(1) | VLV_RC_CTL_CTX_RST_PARALLEL;
> +
> +	I915_WRITE(GEN6_RC_CONTROL, rc6_mode);
> +
> +	gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL);
> +}
> +

Can you send me a link to the doc for this off-list? I am having trouble
tracking it down.

>  static void valleyview_enable_rps(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -4550,7 +4639,9 @@ void intel_disable_gt_powersave(struct drm_device *dev)
>  		cancel_delayed_work_sync(&dev_priv->rps.delayed_resume_work);
>  		cancel_work_sync(&dev_priv->rps.work);
>  		mutex_lock(&dev_priv->rps.hw_lock);
> -		if (IS_VALLEYVIEW(dev))
> +		if (IS_CHERRYVIEW(dev))
> +			cherryview_disable_rps(dev);
> +		else if (IS_VALLEYVIEW(dev))
>  			valleyview_disable_rps(dev);
>  		else
>  			gen6_disable_rps(dev);
> @@ -4568,7 +4659,9 @@ static void intel_gen6_powersave_work(struct work_struct *work)
>  
>  	mutex_lock(&dev_priv->rps.hw_lock);
>  
> -	if (IS_VALLEYVIEW(dev)) {
> +	if (IS_CHERRYVIEW(dev)) {
> +		cherryview_enable_rps(dev);
> +	} else if (IS_VALLEYVIEW(dev)) {
>  		valleyview_enable_rps(dev);
>  	} else if (IS_BROADWELL(dev)) {
>  		gen8_enable_rps(dev);
> @@ -4590,6 +4683,8 @@ void intel_enable_gt_powersave(struct drm_device *dev)
>  		ironlake_enable_rc6(dev);
>  		intel_init_emon(dev);
>  	} else if (IS_GEN6(dev) || IS_GEN7(dev)) {
> +		if (IS_VALLEYVIEW(dev))
> +			valleyview_setup_pctx(dev);

Spurious hunk?

>  		/*
>  		 * PCU communication is slow and this doesn't need to be
>  		 * done at any specific time, so do this out of our fast path
> @@ -5175,6 +5270,7 @@ static void valleyview_init_clock_gating(struct drm_device *dev)
>  		dev_priv->mem_freq = 1333;
>  		break;
>  	}
> +

Spurious hunk?

>  	DRM_DEBUG_DRIVER("DDR speed: %d MHz", dev_priv->mem_freq);
>  
>  	dev_priv->vlv_cdclk_freq = valleyview_cur_cdclk(dev_priv);

I think for enabling this patch is fine as is. It does need some of the
fixes I mentioned about. So I'd suggest adding FIXMes with what I
request, and calling this
Acked-by: Ben Widawsky <ben@bwidawsk.net>

To move it up to a reviewed by, I need to find the PM doc (which I
probably have, just don't know it), and I'd like the setup function
fixed.



-- 
Ben Widawsky, Intel Open Source Technology Center