drm/i915/psr: Bring back HSW/BDW PSR AUX CH registers/setup

Reintroduce the special PSR AUX CH setup for hsw/bdw. Not all
of it was even removed (BDW AUX data registers were left behind).
Update the code to use REG_BIT() & co. while at it.

v2: Define the SRD_AUX_CTL bits in terms of DP_AUX_CTL bits (Jouni)
    Add a comment explaining the hand rolled DPCD write (Jouni)

Cc: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230609141404.12729-6-ville.syrjala@linux.intel.comReviewed-by: Jouni Högander <jouni.hogander@intel.com>

drivers/gpu/drm/i915/display/intel_dp_aux.c

@@ -14,7 +14,7 @@
 #include "intel_pps.h"
 #include "intel_tc.h"
 
-static u32 intel_dp_aux_pack(const u8 *src, int src_bytes)
+u32 intel_dp_aux_pack(const u8 *src, int src_bytes)
 {
 	int i;
 	u32 v = 0;

drivers/gpu/drm/i915/display/intel_dp_aux.h

@@ -6,6 +6,8 @@
 #ifndef __INTEL_DP_AUX_H__
 #define __INTEL_DP_AUX_H__
 
+#include <linux/types.h>
+
 enum aux_ch;
 struct drm_i915_private;
 struct intel_dp;
@@ -17,5 +19,6 @@ void intel_dp_aux_init(struct intel_dp *intel_dp);
 enum aux_ch intel_dp_aux_ch(struct intel_encoder *encoder);
 
 void intel_dp_aux_irq_handler(struct drm_i915_private *i915);
+u32 intel_dp_aux_pack(const u8 *src, int src_bytes);
 
 #endif /* __INTEL_DP_AUX_H__ */

drivers/gpu/drm/i915/display/intel_psr.c

@@ -288,6 +288,24 @@ static i915_reg_t psr_iir_reg(struct drm_i915_private *dev_priv,
 		return EDP_PSR_IIR;
 }
 
+static i915_reg_t psr_aux_ctl_reg(struct drm_i915_private *dev_priv,
+				  enum transcoder cpu_transcoder)
+{
+	if (DISPLAY_VER(dev_priv) >= 8)
+		return EDP_PSR_AUX_CTL(cpu_transcoder);
+	else
+		return HSW_SRD_AUX_CTL;
+}
+
+static i915_reg_t psr_aux_data_reg(struct drm_i915_private *dev_priv,
+				   enum transcoder cpu_transcoder, int i)
+{
+	if (DISPLAY_VER(dev_priv) >= 8)
+		return EDP_PSR_AUX_DATA(cpu_transcoder, i);
+	else
+		return HSW_SRD_AUX_DATA(i);
+}
+
 static void psr_irq_control(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
@@ -512,6 +530,43 @@ void intel_psr_init_dpcd(struct intel_dp *intel_dp)
 	}
 }
 
+static void hsw_psr_setup_aux(struct intel_dp *intel_dp)
+{
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+	enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
+	u32 aux_clock_divider, aux_ctl;
+	/* write DP_SET_POWER=D0 */
+	static const u8 aux_msg[] = {
+		[0] = (DP_AUX_NATIVE_WRITE << 4) | ((DP_SET_POWER >> 16) & 0xf),
+		[1] = (DP_SET_POWER >> 8) & 0xff,
+		[2] = DP_SET_POWER & 0xff,
+		[3] = 1 - 1,
+		[4] = DP_SET_POWER_D0,
+	};
+	int i;
+
+	BUILD_BUG_ON(sizeof(aux_msg) > 20);
+	for (i = 0; i < sizeof(aux_msg); i += 4)
+		intel_de_write(dev_priv,
+			       psr_aux_data_reg(dev_priv, cpu_transcoder, i >> 2),
+			       intel_dp_aux_pack(&aux_msg[i], sizeof(aux_msg) - i));
+
+	aux_clock_divider = intel_dp->get_aux_clock_divider(intel_dp, 0);
+
+	/* Start with bits set for DDI_AUX_CTL register */
+	aux_ctl = intel_dp->get_aux_send_ctl(intel_dp, sizeof(aux_msg),
+					     aux_clock_divider);
+
+	/* Select only valid bits for SRD_AUX_CTL */
+	aux_ctl &= EDP_PSR_AUX_CTL_TIME_OUT_MASK |
+		EDP_PSR_AUX_CTL_MESSAGE_SIZE_MASK |
+		EDP_PSR_AUX_CTL_PRECHARGE_2US_MASK |
+		EDP_PSR_AUX_CTL_BIT_CLOCK_2X_MASK;
+
+	intel_de_write(dev_priv, psr_aux_ctl_reg(dev_priv, cpu_transcoder),
+		       aux_ctl);
+}
+
 static void intel_psr_enable_sink(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
@@ -1318,6 +1373,13 @@ static void intel_psr_enable_source(struct intel_dp *intel_dp,
 	enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
 	u32 mask;
 
+	/*
+	 * Only HSW and BDW have PSR AUX registers that need to be setup.
+	 * SKL+ use hardcoded values PSR AUX transactions
+	 */
+	if (DISPLAY_VER(dev_priv) < 9)
+		hsw_psr_setup_aux(intel_dp);
+
 	/*
 	 * Per Spec: Avoid continuous PSR exit by masking MEMUP and HPD also
 	 * mask LPSP to avoid dependency on other drivers that might block

drivers/gpu/drm/i915/display/intel_psr_regs.h

@@ -7,6 +7,7 @@
 #define __INTEL_PSR_REGS_H__
 
 #include "intel_display_reg_defs.h"
+#include "intel_dp_aux_regs.h"
 
 #define TRANS_EXITLINE(trans)	_MMIO_TRANS2((trans), _TRANS_EXITLINE_A)
 #define   EXITLINE_ENABLE	REG_BIT(31)
@@ -80,6 +81,17 @@
 #define   EDP_PSR_PRE_ENTRY(trans)	(TGL_PSR_PRE_ENTRY <<		\
 					 _EDP_PSR_TRANS_SHIFT(trans))
 
+#define HSW_SRD_AUX_CTL				_MMIO(0x64810)
+#define _SRD_AUX_CTL_A				0x60810
+#define _SRD_AUX_CTL_EDP			0x6f810
+#define EDP_PSR_AUX_CTL(tran)			_MMIO_TRANS2(tran, _SRD_AUX_CTL_A)
+#define   EDP_PSR_AUX_CTL_TIME_OUT_MASK		DP_AUX_CH_CTL_TIME_OUT_MASK
+#define   EDP_PSR_AUX_CTL_MESSAGE_SIZE_MASK	DP_AUX_CH_CTL_MESSAGE_SIZE_MASK
+#define   EDP_PSR_AUX_CTL_PRECHARGE_2US_MASK	DP_AUX_CH_CTL_PRECHARGE_2US_MASK
+#define   EDP_PSR_AUX_CTL_ERROR_INTERRUPT	REG_BIT(11)
+#define   EDP_PSR_AUX_CTL_BIT_CLOCK_2X_MASK	DP_AUX_CH_CTL_BIT_CLOCK_2X_MASK
+
+#define HSW_SRD_AUX_DATA(i)			_MMIO(0x64814 + (i) * 4) /* 5 registers */
 #define _SRD_AUX_DATA_A				0x60814
 #define _SRD_AUX_DATA_EDP			0x6f814
 #define EDP_PSR_AUX_DATA(tran, i)		_MMIO_TRANS2(tran, _SRD_AUX_DATA_A + (i) * 4) /* 5 registers */