drm/i915/dp: Add a standalone function to obtain shared dpll for HSW/BDW/SKL/BXT

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.

v4:
* Removed dereferencing NULL pointer in  case of failure (Dhinakaran Pandiyan)
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@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Jim Bride <jim.bride@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index e4b875e..25e7973 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2393,6 +2393,45 @@ 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);
+			return NULL;
+		}
+		tmp_pll_config = pll->config;
+		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;
+			return NULL;
+		}
+	} 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);