drm/i915: rework digital port IRQ handling (v2)

The digital ports from Ironlake and up have the ability to distinguish
between long and short HPD pulses. Displayport 1.1 only uses the short
form to request link retraining usually, so we haven't really needed
support for it until now.

However with DP 1.2 MST we need to handle the short irqs on their
own outside the modesetting locking the long hpd's involve. This
patch adds the framework to distinguish between short/long to the
current code base, to lay the basis for future DP 1.2 MST work.

This should mean we get better bisectability in case of regression
due to the new irq handling.

v2: add GM45 support (untested, due to lack of hw)

Signed-off-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Todd Previte <tprevite@gmail.com>
[danvet: Fix conflicts in i915_irq.c with Oscar Mateo's irq handling
race fixes and a trivial one in intel_drv.h with the psr code.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1559,6 +1559,11 @@ struct drm_i915_private {
 
 	struct i915_runtime_pm pm;
 
+	struct intel_digital_port *hpd_irq_port[I915_MAX_PORTS];
+	u32 long_hpd_port_mask;
+	u32 short_hpd_port_mask;
+	struct work_struct dig_port_work;
+
 	/* Old dri1 support infrastructure, beware the dragons ya fools entering
 	 * here! */
 	struct i915_dri1_state dri1;

drivers/gpu/drm/i915/i915_irq.c

@@ -1090,6 +1090,53 @@ static bool intel_hpd_irq_event(struct drm_device *dev,
 	return true;
 }
 
+static void i915_digport_work_func(struct work_struct *work)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(work, struct drm_i915_private, dig_port_work);
+	unsigned long irqflags;
+	u32 long_port_mask, short_port_mask;
+	struct intel_digital_port *intel_dig_port;
+	int i, ret;
+	u32 old_bits = 0;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+	long_port_mask = dev_priv->long_hpd_port_mask;
+	dev_priv->long_hpd_port_mask = 0;
+	short_port_mask = dev_priv->short_hpd_port_mask;
+	dev_priv->short_hpd_port_mask = 0;
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+
+	for (i = 0; i < I915_MAX_PORTS; i++) {
+		bool valid = false;
+		bool long_hpd = false;
+		intel_dig_port = dev_priv->hpd_irq_port[i];
+		if (!intel_dig_port || !intel_dig_port->hpd_pulse)
+			continue;
+
+		if (long_port_mask & (1 << i))  {
+			valid = true;
+			long_hpd = true;
+		} else if (short_port_mask & (1 << i))
+			valid = true;
+
+		if (valid) {
+			ret = intel_dig_port->hpd_pulse(intel_dig_port, long_hpd);
+			if (ret == true) {
+				/* if we get true fallback to old school hpd */
+				old_bits |= (1 << intel_dig_port->base.hpd_pin);
+			}
+		}
+	}
+
+	if (old_bits) {
+		spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+		dev_priv->hpd_event_bits |= old_bits;
+		spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+		schedule_work(&dev_priv->hotplug_work);
+	}
+}
+
 /*
  * Handle hotplug events outside the interrupt handler proper.
  */
@@ -1521,23 +1568,104 @@ static irqreturn_t gen8_gt_irq_handler(struct drm_device *dev,
 #define HPD_STORM_DETECT_PERIOD 1000
 #define HPD_STORM_THRESHOLD 5
 
+static int ilk_port_to_hotplug_shift(enum port port)
+{
+	switch (port) {
+	case PORT_A:
+	case PORT_E:
+	default:
+		return -1;
+	case PORT_B:
+		return 0;
+	case PORT_C:
+		return 8;
+	case PORT_D:
+		return 16;
+	}
+}
+
+static int g4x_port_to_hotplug_shift(enum port port)
+{
+	switch (port) {
+	case PORT_A:
+	case PORT_E:
+	default:
+		return -1;
+	case PORT_B:
+		return 17;
+	case PORT_C:
+		return 19;
+	case PORT_D:
+		return 21;
+	}
+}
+
+static inline enum port get_port_from_pin(enum hpd_pin pin)
+{
+	switch (pin) {
+	case HPD_PORT_B:
+		return PORT_B;
+	case HPD_PORT_C:
+		return PORT_C;
+	case HPD_PORT_D:
+		return PORT_D;
+	default:
+		return PORT_A; /* no hpd */
+	}
+}
+
 static inline void intel_hpd_irq_handler(struct drm_device *dev,
 					 u32 hotplug_trigger,
+					 u32 dig_hotplug_reg,
 					 const u32 *hpd)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int i;
+	enum port port;
 	bool storm_detected = false;
+	bool queue_dig = false, queue_hp = false;
+	u32 dig_shift;
+	u32 dig_port_mask = 0;
 
 	if (!hotplug_trigger)
 		return;
 
-	DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
-			  hotplug_trigger);
+	DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x, dig 0x%08x\n",
+			 hotplug_trigger, dig_hotplug_reg);
 
 	spin_lock(&dev_priv->irq_lock);
 	for (i = 1; i < HPD_NUM_PINS; i++) {
+		if (!(hpd[i] & hotplug_trigger))
+			continue;
 
+		port = get_port_from_pin(i);
+		if (port && dev_priv->hpd_irq_port[port]) {
+			bool long_hpd;
+
+			if (IS_G4X(dev)) {
+				dig_shift = g4x_port_to_hotplug_shift(port);
+				long_hpd = (hotplug_trigger >> dig_shift) & PORTB_HOTPLUG_LONG_DETECT;
+			} else {
+				dig_shift = ilk_port_to_hotplug_shift(port);
+				long_hpd = (dig_hotplug_reg >> dig_shift) & PORTB_HOTPLUG_LONG_DETECT;
+			}
+
+			DRM_DEBUG_DRIVER("digital hpd port %d %d\n", port, long_hpd);
+			/* for long HPD pulses we want to have the digital queue happen,
+			   but we still want HPD storm detection to function. */
+			if (long_hpd) {
+				dev_priv->long_hpd_port_mask |= (1 << port);
+				dig_port_mask |= hpd[i];
+			} else {
+				/* for short HPD just trigger the digital queue */
+				dev_priv->short_hpd_port_mask |= (1 << port);
+				hotplug_trigger &= ~hpd[i];
+			}
+			queue_dig = true;
+		}
+	}
+
+	for (i = 1; i < HPD_NUM_PINS; i++) {
 		if (hpd[i] & hotplug_trigger &&
 		    dev_priv->hpd_stats[i].hpd_mark == HPD_DISABLED) {
 			/*
@@ -1557,7 +1685,11 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev,
 		    dev_priv->hpd_stats[i].hpd_mark != HPD_ENABLED)
 			continue;
 
-		dev_priv->hpd_event_bits |= (1 << i);
+		if (!(dig_port_mask & hpd[i])) {
+			dev_priv->hpd_event_bits |= (1 << i);
+			queue_hp = true;
+		}
+
 		if (!time_in_range(jiffies, dev_priv->hpd_stats[i].hpd_last_jiffies,
 				   dev_priv->hpd_stats[i].hpd_last_jiffies
 				   + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD))) {
@@ -1586,7 +1718,10 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev,
 	 * queue for otherwise the flush_work in the pageflip code will
 	 * deadlock.
 	 */
-	schedule_work(&dev_priv->hotplug_work);
+	if (queue_dig)
+		schedule_work(&dev_priv->dig_port_work);
+	if (queue_hp)
+		schedule_work(&dev_priv->hotplug_work);
 }
 
 static void gmbus_irq_handler(struct drm_device *dev)
@@ -1827,11 +1962,11 @@ static void i9xx_hpd_irq_handler(struct drm_device *dev)
 		if (IS_G4X(dev)) {
 			u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_G4X;
 
-			intel_hpd_irq_handler(dev, hotplug_trigger, hpd_status_g4x);
+			intel_hpd_irq_handler(dev, hotplug_trigger, 0, hpd_status_g4x);
 		} else {
 			u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
 
-			intel_hpd_irq_handler(dev, hotplug_trigger, hpd_status_i915);
+			intel_hpd_irq_handler(dev, hotplug_trigger, 0, hpd_status_i915);
 		}
 
 		if ((IS_G4X(dev) || IS_VALLEYVIEW(dev)) &&
@@ -1929,8 +2064,12 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int pipe;
 	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK;
+	u32 dig_hotplug_reg;
 
-	intel_hpd_irq_handler(dev, hotplug_trigger, hpd_ibx);
+	dig_hotplug_reg = I915_READ(PCH_PORT_HOTPLUG);
+	I915_WRITE(PCH_PORT_HOTPLUG, dig_hotplug_reg);
+
+	intel_hpd_irq_handler(dev, hotplug_trigger, dig_hotplug_reg, hpd_ibx);
 
 	if (pch_iir & SDE_AUDIO_POWER_MASK) {
 		int port = ffs((pch_iir & SDE_AUDIO_POWER_MASK) >>
@@ -2036,8 +2175,12 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int pipe;
 	u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;
+	u32 dig_hotplug_reg;
 
-	intel_hpd_irq_handler(dev, hotplug_trigger, hpd_cpt);
+	dig_hotplug_reg = I915_READ(PCH_PORT_HOTPLUG);
+	I915_WRITE(PCH_PORT_HOTPLUG, dig_hotplug_reg);
+
+	intel_hpd_irq_handler(dev, hotplug_trigger, dig_hotplug_reg, hpd_cpt);
 
 	if (pch_iir & SDE_AUDIO_POWER_MASK_CPT) {
 		int port = ffs((pch_iir & SDE_AUDIO_POWER_MASK_CPT) >>
@@ -4358,6 +4501,7 @@ void intel_irq_init(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	INIT_WORK(&dev_priv->hotplug_work, i915_hotplug_work_func);
+	INIT_WORK(&dev_priv->dig_port_work, i915_digport_work_func);
 	INIT_WORK(&dev_priv->gpu_error.work, i915_error_work_func);
 	INIT_WORK(&dev_priv->rps.work, gen6_pm_rps_work);
 	INIT_WORK(&dev_priv->l3_parity.error_work, ivybridge_parity_work);

drivers/gpu/drm/i915/intel_ddi.c

@@ -1705,6 +1705,9 @@ void intel_ddi_init(struct drm_device *dev, enum port port)
 	intel_encoder->cloneable = 0;
 	intel_encoder->hot_plug = intel_ddi_hot_plug;
 
+	intel_dig_port->hpd_pulse = intel_dp_hpd_pulse;
+	dev_priv->hpd_irq_port[port] = intel_dig_port;
+
 	if (init_dp)
 		dp_connector = intel_ddi_init_dp_connector(intel_dig_port);
 

drivers/gpu/drm/i915/intel_dp.c

@@ -3815,6 +3815,22 @@ intel_dp_hot_plug(struct intel_encoder *intel_encoder)
 	intel_dp_check_link_status(intel_dp);
 }
 
+bool
+intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
+{
+	struct intel_dp *intel_dp = &intel_dig_port->dp;
+
+	if (long_hpd)
+		return true;
+
+	/*
+	 * we'll check the link status via the normal hot plug path later -
+	 * but for short hpds we should check it now
+	 */
+	intel_dp_check_link_status(intel_dp);
+	return false;
+}
+
 /* Return which DP Port should be selected for Transcoder DP control */
 int
 intel_trans_dp_port_sel(struct drm_crtc *crtc)
@@ -4387,6 +4403,7 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 void
 intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_digital_port *intel_dig_port;
 	struct intel_encoder *intel_encoder;
 	struct drm_encoder *encoder;
@@ -4443,6 +4460,9 @@ intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
 	intel_encoder->cloneable = 0;
 	intel_encoder->hot_plug = intel_dp_hot_plug;
 
+	intel_dig_port->hpd_pulse = intel_dp_hpd_pulse;
+	dev_priv->hpd_irq_port[port] = intel_dig_port;
+
 	if (!intel_dp_init_connector(intel_dig_port, intel_connector)) {
 		drm_encoder_cleanup(encoder);
 		kfree(intel_dig_port);

drivers/gpu/drm/i915/intel_drv.h

@@ -567,6 +567,7 @@ struct intel_digital_port {
 	u32 saved_port_bits;
 	struct intel_dp dp;
 	struct intel_hdmi hdmi;
+	bool (*hpd_pulse)(struct intel_digital_port *, bool);
 };
 
 static inline int
@@ -850,6 +851,8 @@ int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc);
 bool intel_dp_compute_config(struct intel_encoder *encoder,
 			     struct intel_crtc_config *pipe_config);
 bool intel_dp_is_edp(struct drm_device *dev, enum port port);
+bool intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port,
+			bool long_hpd);
 void intel_edp_backlight_on(struct intel_dp *intel_dp);
 void intel_edp_backlight_off(struct intel_dp *intel_dp);
 void intel_edp_panel_vdd_on(struct intel_dp *intel_dp);
@@ -861,7 +864,6 @@ void intel_dp_set_drrs_state(struct drm_device *dev, int refresh_rate);
 void intel_edp_psr_exit(struct drm_device *dev);
 void intel_edp_psr_init(struct drm_device *dev);
 
-
 /* intel_dsi.c */
 void intel_dsi_init(struct drm_device *dev);