[Intel-gfx] [PATCH 1/2] drm/i915/dsi/xelpd: Add WA to program LP to HS wakeup guardband

[Vandita Kulkarni]

Wa_16012360555 SW will have to program the "LP to HS Wakeup Guardband"
field to account for the repeaters on the HS Request/Ready PPI signaling
between the Display engine and the DPHY.

Signed-off-by: Vandita Kulkarni <vandita.kulkarni at intel.com>
---
 drivers/gpu/drm/i915/display/icl_dsi.c | 24 ++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_reg.h        |  8 ++++++++
 2 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c
index 43ec7fcd3f5d..61aea695c565 100644
--- a/drivers/gpu/drm/i915/display/icl_dsi.c
+++ b/drivers/gpu/drm/i915/display/icl_dsi.c
@@ -1270,6 +1270,27 @@ static void icl_apply_kvmr_pipe_a_wa(struct intel_encoder *encoder,
 			     IGNORE_KVMR_PIPE_A,
 			     enable ? IGNORE_KVMR_PIPE_A : 0);
 }
+
+/*
+ * Wa_16012360555:ADLP
+ * SW will have to program the "LP to HS Wakeup Guardband"
+ * field (bits 15:12) of register offset 0x6B0C0 (DSI0)
+ * and 0x6B8C0 (DSI1) to a value of 4 to account for the repeaters
+ * on the HS Request/Ready PPI signaling between
+ * the Display engine and the DPHY.
+ */
+static void adlp_set_lp_hs_wakeup_gb(struct intel_encoder *encoder)
+{
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);
+	enum port port;
+
+	if (DISPLAY_VER(dev_priv) == 13)
+		for_each_dsi_port(port, intel_dsi->ports)
+			intel_de_rmw(dev_priv, TGL_DSI_CHKN_REG(port),
+				     TGL_DSI_CHKN_LSHS_GB, 0x4);
+}
+
 static void gen11_dsi_enable(struct intel_atomic_state *state,
 			     struct intel_encoder *encoder,
 			     const struct intel_crtc_state *crtc_state,
@@ -1283,6 +1304,9 @@ static void gen11_dsi_enable(struct intel_atomic_state *state,
 	/* Wa_1409054076:icl,jsl,ehl */
 	icl_apply_kvmr_pipe_a_wa(encoder, crtc->pipe, true);
 
+	/* Wa_16012360555: adlp */
+	adlp_set_lp_hs_wakeup_gb(encoder);
+
 	/* step6d: enable dsi transcoder */
 	gen11_dsi_enable_transcoder(encoder);
 
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 72dd3a6d205d..34ad288de748 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -11614,6 +11614,14 @@ enum skl_power_gate {
 						    _ICL_DSI_IO_MODECTL_1)
 #define  COMBO_PHY_MODE_DSI				(1 << 0)
 
+/* TGL DSI Chicken register */
+#define TGL_DSI_CHKN_REG_0			0x6B0C0
+#define TGL_DSI_CHKN_REG_1			0x6B8C0
+#define TGL_DSI_CHKN_REG(port)		_MMIO_PORT(port,	\
+						    _TGL_DSI_CHKN_REG_0, \
+						    _TGL_DSI_CHKN_REG_1)
+#define TGL_DSI_CHKN_LSHS_GB			(0xF << 12)
+
 /* Display Stream Splitter Control */
 #define DSS_CTL1				_MMIO(0x67400)
 #define  SPLITTER_ENABLE			(1 << 31)
-- 
2.32.0