[Intel-gfx] [PATCH 09/19] drm/i915: automatic FDI training support for Ivy Bridge

[Jesse Barnes]

On Thu, 28 Apr 2011 15:12:55 -0700
Jesse Barnes <jbarnes at virtuousgeek.org> wrote:

> Ivy Bridge supports auto-training on the CPU side, so add a separate
> training function to handle it.
> 
> Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> ---
>  drivers/gpu/drm/i915/i915_reg.h      |    2 +
>  drivers/gpu/drm/i915/intel_display.c |   82 +++++++++++++++++++++++++++++++--
>  2 files changed, 79 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index aba3fe5..03c99ed 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -3116,6 +3116,8 @@
>  #define  FDI_LINK_TRAIN_AUTO		(1<<10)
>  #define  FDI_SCRAMBLING_ENABLE          (0<<7)
>  #define  FDI_SCRAMBLING_DISABLE         (1<<7)
> +/* Ivybridge */
> +#define  FDI_AUTO_TRAIN_DONE		(1<<1)
>  
>  /* FDI_RX, FDI_X is hard-wired to Transcoder_X */
>  #define _FDI_RXA_CTL             0xf000c
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index ab840a6..3396043 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -2411,6 +2411,75 @@ static void ivb_manual_fdi_link_train(struct drm_crtc *crtc)
>  	DRM_DEBUG_KMS("FDI train done.\n");
>  }
>  
> +/* On Ivybridge we can use auto training */
> +static void ivb_fdi_link_train(struct drm_crtc *crtc)
> +{
> +	struct drm_device *dev = crtc->dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> +	unsigned long start = jiffies_to_msecs(jiffies);
> +	int pipe = intel_crtc->pipe;
> +	u32 reg, temp, i, j;
> +
> +	/* Can't pair IVB & Ibex Peak */
> +	BUG_ON(HAS_PCH_IBX(dev));
> +
> +	reg = FDI_TX_CTL(pipe);
> +	temp = I915_READ(reg);
> +	temp &= ~(7 << 19);
> +	temp |= (intel_crtc->fdi_lanes - 1) << 19;
> +	temp &= ~FDI_LINK_TRAIN_NONE;
> +	I915_WRITE(reg, temp);
> +
> +	/* Enable auto training on TX and RX */
> +	for (i = 0; i < ARRAY_SIZE(snb_b_fdi_train_param); i++) {
> +		/* Try each vswing/pre-emphasis pair twice */
> +		for (j = 0; j < 2; j++) {
> +			reg = FDI_TX_CTL(pipe);
> +			temp = I915_READ(reg);
> +			temp |= FDI_AUTO_TRAINING;
> +			temp &= ~FDI_LINK_TRAIN_VOL_EMP_MASK;
> +			temp |= snb_b_fdi_train_param[i];
> +			I915_WRITE(reg, temp | FDI_TX_ENABLE);
> +
> +			reg = FDI_RX_CTL(pipe);
> +			temp = I915_READ(reg);
> +			I915_WRITE(reg, temp | FDI_RX_ENABLE);
> +			POSTING_READ(reg);
> +
> +			udelay(5);
> +
> +			reg = FDI_TX_CTL(pipe);
> +			temp = I915_READ(reg);
> +			if ((temp & FDI_AUTO_TRAIN_DONE) ||
> +			    (I915_READ(reg) & FDI_AUTO_TRAIN_DONE)) {
> +				DRM_DEBUG_KMS("FDI auto train complete in %d ms\n",
> +					      jiffies_to_msecs(jiffies) - start);
> +				goto done;
> +			}
> +
> +			reg = FDI_TX_CTL(pipe);
> +			temp = I915_READ(reg);
> +			I915_WRITE(reg, temp & ~FDI_TX_ENABLE);
> +
> +			reg = FDI_RX_CTL(pipe);
> +			temp = I915_READ(reg);
> +			I915_WRITE(reg, temp & ~FDI_RX_ENABLE);
> +			POSTING_READ(reg);
> +			udelay(31); /* wait idle time before retrying */
> +		}
> +	}
> +	DRM_ERROR("FDI auto train failed\n");
> +	return;
> +
> +done:
> +	reg = FDI_RX_CTL(pipe);
> +	temp = I915_READ(reg);
> +	temp |= FDI_FS_ERR_CORRECT_ENABLE | FDI_FE_ERR_CORRECT_ENABLE;
> +	I915_WRITE(reg, temp);
> +	POSTING_READ(reg);
> +}
> +
>  static void ironlake_fdi_pll_enable(struct drm_crtc *crtc)
>  {
>  	struct drm_device *dev = crtc->dev;
> @@ -2452,7 +2521,7 @@ static void ironlake_fdi_pll_enable(struct drm_crtc *crtc)
>  	}
>  }
>  
> -static void ironlake_fdi_disable(struct drm_crtc *crtc)
> +static void ironlake_fdi_pll_disable(struct drm_crtc *crtc)
>  {
>  	struct drm_device *dev = crtc->dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -2674,9 +2743,9 @@ static void ironlake_crtc_enable(struct drm_crtc *crtc)
>  	is_pch_port = intel_crtc_driving_pch(crtc);
>  
>  	if (is_pch_port)
> -		ironlake_fdi_enable(crtc);
> +		ironlake_fdi_pll_enable(crtc);
>  	else
> -		ironlake_fdi_disable(crtc);
> +		ironlake_fdi_pll_disable(crtc);
>  
>  	/* Enable panel fitting for LVDS */
>  	if (dev_priv->pch_pf_size &&
> @@ -2729,7 +2798,7 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc)
>  	I915_WRITE(PF_CTL(pipe), 0);
>  	I915_WRITE(PF_WIN_SZ(pipe), 0);
>  
> -	ironlake_fdi_disable(crtc);
> +	ironlake_fdi_pll_disable(crtc);

arg, screwed up the rebase here; the fdi_pll name change needs to stay
together.

-- 
Jesse Barnes, Intel Open Source Technology Center