[Intel-gfx] [PATCH 1/2] drm/i915/ehl/dsi: Set lane latency optimization for DW1

[José Roberto de Souza]

From: Vandita Kulkarni <vandita.kulkarni at intel.com>

EHL has 2 additional steps in the DSI sequence, this is one of then
the lane latency optimization for DW1.

BSpec: 20597
Cc: Uma Shankar <uma.shankar at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Jani Nikula <jani.nikula at intel.com>
Signed-off-by: Vandita Kulkarni <vandita.kulkarni at intel.com>
---
 drivers/gpu/drm/i915/display/icl_dsi.c | 11 +++++++++++
 drivers/gpu/drm/i915/i915_reg.h        |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c
index 74448e6bf749..ee85428b309f 100644
--- a/drivers/gpu/drm/i915/display/icl_dsi.c
+++ b/drivers/gpu/drm/i915/display/icl_dsi.c
@@ -403,6 +403,17 @@ static void gen11_dsi_config_phy_lanes_sequence(struct intel_encoder *encoder)
 		tmp &= ~FRC_LATENCY_OPTIM_MASK;
 		tmp |= FRC_LATENCY_OPTIM_VAL(0x5);
 		I915_WRITE(ICL_PORT_TX_DW2_GRP(port), tmp);
+		/* For EHL set latency optimization for PCS_DW1 lanes */
+		if (IS_ELKHARTLAKE(dev_priv)) {
+			tmp = I915_READ(ICL_PORT_PCS_DW1_AUX(port));
+			tmp &= ~LATENCY_OPTIM_MASK;
+			tmp |= LATENCY_OPTIM_VAL(0);
+			I915_WRITE(ICL_PORT_PCS_DW1_AUX(port), tmp);
+			tmp = I915_READ(ICL_PORT_PCS_DW1_LN0(port));
+			tmp &= ~LATENCY_OPTIM_MASK;
+			tmp |= LATENCY_OPTIM_VAL(0x1);
+			I915_WRITE(ICL_PORT_PCS_DW1_GRP(port), tmp);
+		}
 	}
 
 }
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index d6483b5dc8e5..1f2c3ebdf87b 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1896,6 +1896,8 @@ enum i915_power_well_id {
 #define ICL_PORT_PCS_DW1_GRP(port)	_MMIO(_ICL_PORT_PCS_DW_GRP(1, port))
 #define ICL_PORT_PCS_DW1_LN0(port)	_MMIO(_ICL_PORT_PCS_DW_LN(1, 0, port))
 #define   COMMON_KEEPER_EN		(1 << 26)
+#define   LATENCY_OPTIM_MASK		(0x3 << 2)
+#define   LATENCY_OPTIM_VAL(x)		((x) << 2)
 
 /* CNL/ICL Port TX registers */
 #define _CNL_PORT_TX_AE_GRP_OFFSET		0x162340
-- 
2.22.0