drm/i915/psr: Fix PSR_IMR/IIR field handling

Current PSR code is supposed to use TRANSCODER_EDP to force 0 shift for
bits in PSR_IMR/IIR registers:

/*
 * gen12+ has registers relative to transcoder and one per transcoder
 * using the same bit definition: handle it as TRANSCODER_EDP to force
 * 0 shift in bit definition
 */

At the time of writing the code assumption "TRANSCODER_EDP == 0" was made.
This is not the case and all fields in PSR_IMR and PSR_IIR are shifted
incorrectly if DISPLAY_VER >= 12.

Fix this by adding separate register field defines for >=12 and add bit
getter functions to keep code readability.

v4:
 - Remove EDP from TGL definitions (José)
 - Use REG_BIT and REG_GENMASK (José)
v3:
 - Add separate register field defines (José)
 - Add bit getter functions (José)
v2:
 - Improve commit message (José)

Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Mika Kahola <mika.kahola@intel.com>

Fixes: 8241cfbe ("drm/i915/tgl: Access the right register when handling PSR interruptions")
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221003072011.72408-1-jouni.hogander@intel.com

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

@@ -116,34 +116,56 @@ static bool psr2_global_enabled(struct intel_dp *intel_dp)
 	}
 }
 
+static u32 psr_irq_psr_error_bit_get(struct intel_dp *intel_dp)
+{
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+
+	return DISPLAY_VER(dev_priv) >= 12 ? TGL_PSR_ERROR :
+		EDP_PSR_ERROR(intel_dp->psr.transcoder);
+}
+
+static u32 psr_irq_post_exit_bit_get(struct intel_dp *intel_dp)
+{
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+
+	return DISPLAY_VER(dev_priv) >= 12 ? TGL_PSR_POST_EXIT :
+		EDP_PSR_POST_EXIT(intel_dp->psr.transcoder);
+}
+
+static u32 psr_irq_pre_entry_bit_get(struct intel_dp *intel_dp)
+{
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+
+	return DISPLAY_VER(dev_priv) >= 12 ? TGL_PSR_PRE_ENTRY :
+		EDP_PSR_PRE_ENTRY(intel_dp->psr.transcoder);
+}
+
+static u32 psr_irq_mask_get(struct intel_dp *intel_dp)
+{
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+
+	return DISPLAY_VER(dev_priv) >= 12 ? TGL_PSR_MASK :
+		EDP_PSR_MASK(intel_dp->psr.transcoder);
+}
+
 static void psr_irq_control(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
-	enum transcoder trans_shift;
 	i915_reg_t imr_reg;
 	u32 mask, val;
 
-	/*
-	 * gen12+ has registers relative to transcoder and one per transcoder
-	 * using the same bit definition: handle it as TRANSCODER_EDP to force
-	 * 0 shift in bit definition
-	 */
-	if (DISPLAY_VER(dev_priv) >= 12) {
-		trans_shift = 0;
+	if (DISPLAY_VER(dev_priv) >= 12)
 		imr_reg = TRANS_PSR_IMR(intel_dp->psr.transcoder);
-	} else {
-		trans_shift = intel_dp->psr.transcoder;
+	else
 		imr_reg = EDP_PSR_IMR;
-	}
 
-	mask = EDP_PSR_ERROR(trans_shift);
+	mask = psr_irq_psr_error_bit_get(intel_dp);
 	if (intel_dp->psr.debug & I915_PSR_DEBUG_IRQ)
-		mask |= EDP_PSR_POST_EXIT(trans_shift) |
-			EDP_PSR_PRE_ENTRY(trans_shift);
+		mask |= psr_irq_post_exit_bit_get(intel_dp) |
+			psr_irq_pre_entry_bit_get(intel_dp);
 
-	/* Warning: it is masking/setting reserved bits too */
 	val = intel_de_read(dev_priv, imr_reg);
-	val &= ~EDP_PSR_TRANS_MASK(trans_shift);
+	val &= ~psr_irq_mask_get(intel_dp);
 	val |= ~mask;
 	intel_de_write(dev_priv, imr_reg, val);
 }
@@ -191,25 +213,21 @@ void intel_psr_irq_handler(struct intel_dp *intel_dp, u32 psr_iir)
 	enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
 	ktime_t time_ns =  ktime_get();
-	enum transcoder trans_shift;
 	i915_reg_t imr_reg;
 
-	if (DISPLAY_VER(dev_priv) >= 12) {
-		trans_shift = 0;
+	if (DISPLAY_VER(dev_priv) >= 12)
 		imr_reg = TRANS_PSR_IMR(intel_dp->psr.transcoder);
-	} else {
-		trans_shift = intel_dp->psr.transcoder;
+	else
 		imr_reg = EDP_PSR_IMR;
-	}
 
-	if (psr_iir & EDP_PSR_PRE_ENTRY(trans_shift)) {
+	if (psr_iir & psr_irq_pre_entry_bit_get(intel_dp)) {
 		intel_dp->psr.last_entry_attempt = time_ns;
 		drm_dbg_kms(&dev_priv->drm,
 			    "[transcoder %s] PSR entry attempt in 2 vblanks\n",
 			    transcoder_name(cpu_transcoder));
 	}
 
-	if (psr_iir & EDP_PSR_POST_EXIT(trans_shift)) {
+	if (psr_iir & psr_irq_post_exit_bit_get(intel_dp)) {
 		intel_dp->psr.last_exit = time_ns;
 		drm_dbg_kms(&dev_priv->drm,
 			    "[transcoder %s] PSR exit completed\n",
@@ -226,7 +244,7 @@ void intel_psr_irq_handler(struct intel_dp *intel_dp, u32 psr_iir)
 		}
 	}
 
-	if (psr_iir & EDP_PSR_ERROR(trans_shift)) {
+	if (psr_iir & psr_irq_psr_error_bit_get(intel_dp)) {
 		u32 val;
 
 		drm_warn(&dev_priv->drm, "[transcoder %s] PSR aux error\n",
@@ -243,7 +261,7 @@ void intel_psr_irq_handler(struct intel_dp *intel_dp, u32 psr_iir)
 		 * or unset irq_aux_error.
 		 */
 		val = intel_de_read(dev_priv, imr_reg);
-		val |= EDP_PSR_ERROR(trans_shift);
+		val |= psr_irq_psr_error_bit_get(intel_dp);
 		intel_de_write(dev_priv, imr_reg, val);
 
 		schedule_work(&intel_dp->psr.work);
@@ -1194,14 +1212,12 @@ static bool psr_interrupt_error_check(struct intel_dp *intel_dp)
 	 * first time that PSR HW tries to activate so lets keep PSR disabled
 	 * to avoid any rendering problems.
 	 */
-	if (DISPLAY_VER(dev_priv) >= 12) {
+	if (DISPLAY_VER(dev_priv) >= 12)
 		val = intel_de_read(dev_priv,
 				    TRANS_PSR_IIR(intel_dp->psr.transcoder));
-		val &= EDP_PSR_ERROR(0);
-	} else {
+	else
 		val = intel_de_read(dev_priv, EDP_PSR_IIR);
-		val &= EDP_PSR_ERROR(intel_dp->psr.transcoder);
-	}
+	val &= psr_irq_psr_error_bit_get(intel_dp);
 	if (val) {
 		intel_dp->psr.sink_not_reliable = true;
 		drm_dbg_kms(&dev_priv->drm,

drivers/gpu/drm/i915/i915_reg.h

@@ -2157,10 +2157,18 @@
 #define TRANS_PSR_IIR(tran)			_MMIO_TRANS2(tran, _PSR_IIR_A)
 #define   _EDP_PSR_TRANS_SHIFT(trans)		((trans) == TRANSCODER_EDP ? \
 						 0 : ((trans) - TRANSCODER_A + 1) * 8)
-#define   EDP_PSR_TRANS_MASK(trans)		(0x7 << _EDP_PSR_TRANS_SHIFT(trans))
-#define   EDP_PSR_ERROR(trans)			(0x4 << _EDP_PSR_TRANS_SHIFT(trans))
-#define   EDP_PSR_POST_EXIT(trans)		(0x2 << _EDP_PSR_TRANS_SHIFT(trans))
-#define   EDP_PSR_PRE_ENTRY(trans)		(0x1 << _EDP_PSR_TRANS_SHIFT(trans))
+#define   TGL_PSR_MASK			REG_GENMASK(2, 0)
+#define   TGL_PSR_ERROR			REG_BIT(2)
+#define   TGL_PSR_POST_EXIT		REG_BIT(1)
+#define   TGL_PSR_PRE_ENTRY		REG_BIT(0)
+#define   EDP_PSR_MASK(trans)		(TGL_PSR_MASK <<		\
+					 _EDP_PSR_TRANS_SHIFT(trans))
+#define   EDP_PSR_ERROR(trans)		(TGL_PSR_ERROR <<		\
+					 _EDP_PSR_TRANS_SHIFT(trans))
+#define   EDP_PSR_POST_EXIT(trans)	(TGL_PSR_POST_EXIT <<		\
+					 _EDP_PSR_TRANS_SHIFT(trans))
+#define   EDP_PSR_PRE_ENTRY(trans)	(TGL_PSR_PRE_ENTRY <<		\
+					 _EDP_PSR_TRANS_SHIFT(trans))
 
 #define _SRD_AUX_DATA_A				0x60814
 #define _SRD_AUX_DATA_EDP			0x6f814