[Intel-gfx] [PATCH v3 07/14] drm/i915/dp: Add a standalone function to obtain shared dpll for HSW/BDW/SKL/BXT

[Pandiyan, Dhinakaran]

On Thu, 2016-09-01 at 15:08 -0700, Manasi Navare wrote:
> From: Jim Bride <jim.bride at linux.intel.com>
> 
> Add the PLL selection code for HSW/BDW/BXT/SKL into a stand-alone function
> in order to allow for the implementation of a platform neutral upfront
> link training function.
> 
> v3:
> * Add Hooks for all DDI platforms into this standalone function
> 
> v2:
> * Change the macro to use dev_priv instead of dev (David Weinehall)
> 
> Reviewed-by: Durgadoss R <durgadoss.r at intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> Signed-off-by: Jim Bride <jim.bride at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_ddi.c      | 38 +++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_dpll_mgr.c | 38 +++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_dpll_mgr.h |  2 ++
>  drivers/gpu/drm/i915/intel_drv.h      |  3 ++-
>  4 files changed, 80 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index e4b875e..67a6a0b 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -2393,6 +2393,44 @@ intel_ddi_init_hdmi_connector(struct intel_digital_port *intel_dig_port)
>  	return connector;
>  }
>  
> +struct intel_shared_dpll *
> +intel_ddi_get_link_dpll(struct intel_dp *intel_dp, int clock)
> +{
> +	struct intel_connector *connector = intel_dp->attached_connector;
> +	struct intel_encoder *encoder = connector->encoder;
> +	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> +	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> +	struct intel_shared_dpll *pll = NULL;
> +	struct intel_shared_dpll_config tmp_pll_config;
> +	enum intel_dpll_id dpll_id;
> +
> +	if (IS_BROXTON(dev_priv)) {
> +		dpll_id =  (enum intel_dpll_id)dig_port->port;
> +		/*
> +		 * Select the required PLL. This works for platforms where
> +		 * there is no shared DPLL.
> +		 */
> +		pll = &dev_priv->shared_dplls[dpll_id];
> +		if (WARN_ON(pll->active_mask)) {
> +
> +			DRM_ERROR("Shared DPLL in use. active_mask:%x\n",
> +				  pll->active_mask);
> +			pll = NULL;
> +		}
> +		tmp_pll_config = pll->config;

NULL dereference when pll is in use? 

> +		if (!bxt_ddi_dp_set_dpll_hw_state(clock,
> +						  &pll->config.hw_state)) {
> +			DRM_ERROR("Could not setup DPLL\n");
> +			pll->config = tmp_pll_config;
> +		}
> +	} else if (IS_SKYLAKE(dev_priv)) {
> +		pll = skl_find_link_pll(dev_priv, clock);
> +	} else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv)) {
> +		pll = hsw_ddi_dp_get_dpll(encoder, clock);
> +	}
> +	return pll;
> +}
> +
>  void intel_ddi_init(struct drm_device *dev, enum port port)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(dev);
> diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.c b/drivers/gpu/drm/i915/intel_dpll_mgr.c
> index 9a1da98..4b067ac 100644
> --- a/drivers/gpu/drm/i915/intel_dpll_mgr.c
> +++ b/drivers/gpu/drm/i915/intel_dpll_mgr.c
> @@ -24,6 +24,44 @@
>  #include "intel_drv.h"
>  
>  struct intel_shared_dpll *
> +skl_find_link_pll(struct drm_i915_private *dev_priv, int clock)
> +{
> +	struct intel_shared_dpll *pll = NULL;
> +	struct intel_dpll_hw_state dpll_hw_state;
> +	enum intel_dpll_id i;
> +	bool found = false;
> +
> +	if (!skl_ddi_dp_set_dpll_hw_state(clock, &dpll_hw_state))
> +		return pll;
> +
> +	for (i = DPLL_ID_SKL_DPLL1; i <= DPLL_ID_SKL_DPLL3; i++) {
> +		pll = &dev_priv->shared_dplls[i];
> +
> +		/* Only want to check enabled timings first */
> +		if (pll->config.crtc_mask == 0)
> +			continue;
> +
> +		if (memcmp(&dpll_hw_state, &pll->config.hw_state,
> +			   sizeof(pll->config.hw_state)) == 0) {
> +			found = true;
> +			break;
> +		}
> +	}
> +
> +	/* Ok no matching timings, maybe there's a free one? */
> +	for (i = DPLL_ID_SKL_DPLL1;
> +	     ((found == false) && (i <= DPLL_ID_SKL_DPLL3)); i++) {
> +		pll = &dev_priv->shared_dplls[i];
> +		if (pll->config.crtc_mask == 0) {
> +			pll->config.hw_state = dpll_hw_state;
> +			break;
> +		}
> +	}
> +
> +	return pll;
> +}
> +
> +struct intel_shared_dpll *
>  intel_get_shared_dpll_by_id(struct drm_i915_private *dev_priv,
>  			    enum intel_dpll_id id)
>  {
> diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.h b/drivers/gpu/drm/i915/intel_dpll_mgr.h
> index aed7408..f438535 100644
> --- a/drivers/gpu/drm/i915/intel_dpll_mgr.h
> +++ b/drivers/gpu/drm/i915/intel_dpll_mgr.h
> @@ -168,6 +168,8 @@ bool bxt_ddi_dp_set_dpll_hw_state(int clock,
>  /* SKL dpll related functions */
>  bool skl_ddi_dp_set_dpll_hw_state(int clock,
>  				  struct intel_dpll_hw_state *dpll_hw_state);
> +struct intel_shared_dpll *skl_find_link_pll(struct drm_i915_private *dev_priv,
> +					    int clock);
>  
> 
>  /* HSW dpll related functions */
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 529fa7b..efcd80b 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1159,7 +1159,8 @@ void intel_ddi_clock_get(struct intel_encoder *encoder,
>  			 struct intel_crtc_state *pipe_config);
>  void intel_ddi_set_vc_payload_alloc(struct drm_crtc *crtc, bool state);
>  uint32_t ddi_signal_levels(struct intel_dp *intel_dp);
> -
> +struct intel_shared_dpll *intel_ddi_get_link_dpll(struct intel_dp *intel_dp,
> +						  int clock);
>  unsigned int intel_fb_align_height(struct drm_device *dev,
>  				   unsigned int height,
>  				   uint32_t pixel_format,