[Intel-gfx] [PATCH v3 5/5] drm/i915/display/mtl: Program latch to phy reset

[Radhakrishna Sripada <radhakrishna.sripada@intel.com>]

From: José Roberto de Souza <jose.souza@intel.com>

Latch reset of phys during DC9 and when driver is unloaded to avoid
phy reset.

Specification ask us to program it closer to the step that enables
DC9 in DC_STATE_EN but doing this way allow us to sanitize the phy
latch during driver load.

BSpec: 49197
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
---
 drivers/gpu/drm/i915/display/intel_display_power.c | 8 ++++++++
 drivers/gpu/drm/i915/i915_reg.h                    | 2 ++
 2 files changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 743b919bb2cf..50098c77e3be 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -1624,6 +1624,10 @@ static void icl_display_core_init(struct drm_i915_private *dev_priv,
 	intel_power_well_enable(dev_priv, well);
 	mutex_unlock(&power_domains->lock);
 
+	if (DISPLAY_VER(dev_priv) == 14)
+		intel_de_rmw(dev_priv, DC_STATE_EN,
+			     HOLD_PHY_PG1_LATCH | HOLD_PHY_CLKREQ_PG1_LATCH, 0);
+
 	/* 4. Enable CDCLK. */
 	intel_cdclk_init_hw(dev_priv);
 
@@ -1677,6 +1681,10 @@ static void icl_display_core_uninit(struct drm_i915_private *dev_priv)
 	/* 3. Disable CD clock */
 	intel_cdclk_uninit_hw(dev_priv);
 
+	if (DISPLAY_VER(dev_priv) == 14)
+		intel_de_rmw(dev_priv, DC_STATE_EN, 0,
+			     HOLD_PHY_PG1_LATCH | HOLD_PHY_CLKREQ_PG1_LATCH);
+
 	/*
 	 * 4. Disable Power Well 1 (PG1).
 	 *    The AUX IO power wells are toggled on demand, so they are already
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 7c9ac5b43831..fa1905cc5a99 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7360,6 +7360,8 @@ enum skl_power_gate {
 #define  DC_STATE_DISABLE		0
 #define  DC_STATE_EN_DC3CO		REG_BIT(30)
 #define  DC_STATE_DC3CO_STATUS		REG_BIT(29)
+#define  HOLD_PHY_CLKREQ_PG1_LATCH	REG_BIT(21)
+#define  HOLD_PHY_PG1_LATCH		REG_BIT(20)
 #define  DC_STATE_EN_UPTO_DC5		(1 << 0)
 #define  DC_STATE_EN_DC9		(1 << 3)
 #define  DC_STATE_EN_UPTO_DC6		(2 << 0)
-- 
2.34.1