[PATCH] drm/i915/ehl: Add support for DPLL4 (v5)

[Vivek Kasireddy <vivek.kasireddy@intel.com>]

This patch adds support for DPLL4 on EHL that include the
following restrictions:

- DPLL4 cannot be used with DDIA (combo port A internal eDP usage).
  DPLL4 can be used with other DDIs, including DDID
  (combo port A external usage).

- DPLL4 cannot be enabled when DC5 or DC6 are enabled.

- The DPLL4 enable, lock, power enabled, and power state are connected
  to the MGPLL1_ENABLE register.

v2: (suggestions from Bob Paauwe)
- Rework ehl_get_dpll() function to call intel_find_shared_dpll() and
  iterate twice: once for Combo plls and once for MG plls.

- Use MG pll funcs for DPLL4 instead of creating new ones and modify
  mg_pll_enable to include the restrictions for EHL.

v3: Fix compilation error

v4: (suggestions from Lucas and Ville)
- Treat DPLL4 as a combo phy PLL and not as MG PLL
- Disable DC states when this DPLL is being enabled
- Reuse icl_get_dpll instead of creating a separate one for EHL

v5: (suggestion from Ville)
- Refcount the DC OFF power domains during the enabling and disabling
  of this DPLL.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
---
 drivers/gpu/drm/i915/intel_dpll_mgr.c   | 40 ++++++++++++++++++++++---
 drivers/gpu/drm/i915/intel_dpll_mgr.h   |  5 ++++
 drivers/gpu/drm/i915/intel_runtime_pm.c | 21 +++++++++++++
 drivers/gpu/drm/i915/intel_runtime_pm.h |  5 ++++
 4 files changed, 67 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.c b/drivers/gpu/drm/i915/intel_dpll_mgr.c
index 897d93537414..6d89d231b33d 100644
--- a/drivers/gpu/drm/i915/intel_dpll_mgr.c
+++ b/drivers/gpu/drm/i915/intel_dpll_mgr.c
@@ -22,8 +22,8 @@
  */
 
 #include "intel_dpio_phy.h"
-#include "intel_dpll_mgr.h"
 #include "intel_drv.h"
+#include "intel_dpll_mgr.h"
 
 /**
  * DOC: Display PLLs
@@ -2806,6 +2806,12 @@ icl_get_dpll(struct intel_crtc_state *crtc_state,
 	if (intel_port_is_combophy(dev_priv, port)) {
 		min = DPLL_ID_ICL_DPLL0;
 		max = DPLL_ID_ICL_DPLL1;
+
+		if (IS_ELKHARTLAKE(dev_priv)) {
+			if (encoder->type != INTEL_OUTPUT_EDP)
+				max = DPLL_ID_EHL_DPLL4;
+		}
+
 		ret = icl_calc_dpll_state(crtc_state, encoder);
 	} else if (intel_port_is_tc(dev_priv, port)) {
 		if (encoder->type == INTEL_OUTPUT_DP_MST) {
@@ -2945,8 +2951,14 @@ static bool combo_pll_get_hw_state(struct drm_i915_private *dev_priv,
 				   struct intel_shared_dpll *pll,
 				   struct intel_dpll_hw_state *hw_state)
 {
-	return icl_pll_get_hw_state(dev_priv, pll, hw_state,
-				    CNL_DPLL_ENABLE(pll->info->id));
+	i915_reg_t enable_reg = CNL_DPLL_ENABLE(pll->info->id);
+
+	if (IS_ELKHARTLAKE(dev_priv) &&
+	    pll->info->id == DPLL_ID_EHL_DPLL4) {
+		enable_reg = MG_PLL_ENABLE(0);
+	}
+
+	return icl_pll_get_hw_state(dev_priv, pll, hw_state, enable_reg);
 }
 
 static bool tbt_pll_get_hw_state(struct drm_i915_private *dev_priv,
@@ -3057,6 +3069,14 @@ static void combo_pll_enable(struct drm_i915_private *dev_priv,
 {
 	i915_reg_t enable_reg = CNL_DPLL_ENABLE(pll->info->id);
 
+	if (IS_ELKHARTLAKE(dev_priv) &&
+	    pll->info->id == DPLL_ID_EHL_DPLL4) {
+		enable_reg = MG_PLL_ENABLE(0);
+
+		/* Need to disable DC states when this DPLL is enabled. */
+		icl_disable_dc_states(dev_priv, pll);
+	}
+
 	icl_pll_power_enable(dev_priv, pll, enable_reg);
 
 	icl_dpll_write(dev_priv, pll);
@@ -3152,7 +3172,18 @@ static void icl_pll_disable(struct drm_i915_private *dev_priv,
 static void combo_pll_disable(struct drm_i915_private *dev_priv,
 			      struct intel_shared_dpll *pll)
 {
-	icl_pll_disable(dev_priv, pll, CNL_DPLL_ENABLE(pll->info->id));
+	i915_reg_t enable_reg = CNL_DPLL_ENABLE(pll->info->id);
+
+	if (IS_ELKHARTLAKE(dev_priv) &&
+	    pll->info->id == DPLL_ID_EHL_DPLL4) {
+		enable_reg = MG_PLL_ENABLE(0);
+		icl_pll_disable(dev_priv, pll, enable_reg);
+
+		icl_enable_dc_states(dev_priv, pll);
+		return;
+	}
+
+	icl_pll_disable(dev_priv, pll, enable_reg);
 }
 
 static void tbt_pll_disable(struct drm_i915_private *dev_priv,
@@ -3230,6 +3261,7 @@ static const struct intel_dpll_mgr icl_pll_mgr = {
 static const struct dpll_info ehl_plls[] = {
 	{ "DPLL 0", &combo_pll_funcs, DPLL_ID_ICL_DPLL0, 0 },
 	{ "DPLL 1", &combo_pll_funcs, DPLL_ID_ICL_DPLL1, 0 },
+	{ "DPLL 4", &combo_pll_funcs, DPLL_ID_EHL_DPLL4, 0 },
 	{ },
 };
 
diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.h b/drivers/gpu/drm/i915/intel_dpll_mgr.h
index 8835dd20f1d2..5a70134f539f 100644
--- a/drivers/gpu/drm/i915/intel_dpll_mgr.h
+++ b/drivers/gpu/drm/i915/intel_dpll_mgr.h
@@ -117,6 +117,10 @@ enum intel_dpll_id {
 	 * @DPLL_ID_ICL_DPLL1: ICL combo PHY DPLL1
 	 */
 	DPLL_ID_ICL_DPLL1 = 1,
+	/**
+	 * @DPLL_ID_EHL_DPLL4: EHL combo PHY DPLL4
+	 */
+	DPLL_ID_EHL_DPLL4 = 2,
 	/**
 	 * @DPLL_ID_ICL_TBTPLL: ICL TBT PLL
 	 */
@@ -312,6 +316,7 @@ struct intel_shared_dpll {
 	 * @info: platform specific info
 	 */
 	const struct dpll_info *info;
+	intel_wakeref_t wakerefs[POWER_DOMAIN_NUM];
 };
 
 #define SKL_DPLL0 0
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 12f5b669f20e..09eb5a5e32fa 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -5229,3 +5229,24 @@ void intel_runtime_pm_init_early(struct drm_i915_private *i915)
 {
 	init_intel_runtime_pm_wakeref(i915);
 }
+
+void icl_disable_dc_states(struct drm_i915_private *dev_priv,
+			   struct intel_shared_dpll *pll)
+{
+	enum intel_display_power_domain domain;
+
+	for_each_power_domain(domain, ICL_DISPLAY_DC_OFF_POWER_DOMAINS)
+		pll->wakerefs[domain] = intel_display_power_get(dev_priv,
+							        domain);
+}
+
+void icl_enable_dc_states(struct drm_i915_private *dev_priv,
+			  struct intel_shared_dpll *pll)
+{
+	enum intel_display_power_domain domain;
+
+	for_each_power_domain(domain, ICL_DISPLAY_DC_OFF_POWER_DOMAINS)
+		intel_display_power_put(dev_priv, domain,
+					pll->wakerefs[domain]);
+}
+
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.h b/drivers/gpu/drm/i915/intel_runtime_pm.h
index 0a4c4b3aee7d..a2e8c6799b0a 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.h
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.h
@@ -139,4 +139,9 @@ void chv_phy_powergate_lanes(struct intel_encoder *encoder,
 bool chv_phy_powergate_ch(struct drm_i915_private *dev_priv, enum dpio_phy phy,
 			  enum dpio_channel ch, bool override);
 
+void icl_disable_dc_states(struct drm_i915_private *dev_priv,
+			   struct intel_shared_dpll *pll);
+void icl_enable_dc_states(struct drm_i915_private *dev_priv,
+			  struct intel_shared_dpll *pll);
+
 #endif /* __INTEL_RUNTIME_PM_H__ */
-- 
2.21.0

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