drm/i915: move generic hotplug code into new intel_hotplug.c file

We have enough generic hotplug functions sprinkled all over i915_irq.c
to warrant moving them to a file of their own. This should further
underline the distinction between generic code in the new file and
platform specific hotplug and irq code that remains in i915_irq.c.

Add new intel_hpd_init_work to keep work functions static, and rename
get_port_from_pin to intel_hpd_pin_to_port while increasing its
visibility, but keep everything else the same.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

5 files changed, 464 insertions, 422 deletions

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index b7ddf48e1d75..de2196543367 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -34,6 +34,7 @@ i915-y += i915_cmd_parser.o \
 	  i915_gpu_error.o \
 	  i915_irq.o \
 	  i915_trace_points.o \
+	  intel_hotplug.o \
 	  intel_lrc.o \
 	  intel_ringbuffer.o \
 	  intel_uncore.o
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 78ef0bb53c36..0ec57bad454f 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -541,21 +541,6 @@ bool i915_semaphore_is_enabled(struct drm_device *dev)
 	return true;
 }
 
-void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
-{
-	spin_lock_irq(&dev_priv->irq_lock);
-
-	dev_priv->hotplug.long_port_mask = 0;
-	dev_priv->hotplug.short_port_mask = 0;
-	dev_priv->hotplug.event_bits = 0;
-
-	spin_unlock_irq(&dev_priv->irq_lock);
-
-	cancel_work_sync(&dev_priv->hotplug.dig_port_work);
-	cancel_work_sync(&dev_priv->hotplug.hotplug_work);
-	cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
-}
-
 void i915_firmware_load_error_print(const char *fw_path, int err)
 {
 	DRM_ERROR("failed to load firmware %s (%d)\n", fw_path, err);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 3e36af90f943..c3b9fcf301a0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2601,9 +2601,15 @@ extern unsigned long i915_mch_val(struct drm_i915_private *dev_priv);
 extern unsigned long i915_gfx_val(struct drm_i915_private *dev_priv);
 extern void i915_update_gfx_val(struct drm_i915_private *dev_priv);
 int vlv_force_gfx_clock(struct drm_i915_private *dev_priv, bool on);
-void intel_hpd_cancel_work(struct drm_i915_private *dev_priv);
 void i915_firmware_load_error_print(const char *fw_path, int err);
 
+/* intel_hotplug.c */
+void intel_hpd_irq_handler(struct drm_device *dev, u32 pin_mask, u32 long_mask);
+void intel_hpd_init(struct drm_i915_private *dev_priv);
+void intel_hpd_init_work(struct drm_i915_private *dev_priv);
+void intel_hpd_cancel_work(struct drm_i915_private *dev_priv);
+enum port intel_hpd_pin_to_port(enum hpd_pin pin);
+
 /* i915_irq.c */
 void i915_queue_hangcheck(struct drm_device *dev);
 __printf(3, 4)
@@ -2611,7 +2617,6 @@ void i915_handle_error(struct drm_device *dev, bool wedged,
 		       const char *fmt, ...);
 
 extern void intel_irq_init(struct drm_i915_private *dev_priv);
-extern void intel_hpd_init(struct drm_i915_private *dev_priv);
 int intel_irq_install(struct drm_i915_private *dev_priv);
 void intel_irq_uninstall(struct drm_i915_private *dev_priv);
 
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index ce9eef5f722c..2d3b2ccf9ce4 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -807,125 +807,6 @@ static int i915_get_vblank_timestamp(struct drm_device *dev, int pipe,
 						     &crtc->hwmode);
 }
 
-static bool intel_hpd_irq_event(struct drm_device *dev,
-				struct drm_connector *connector)
-{
-	enum drm_connector_status old_status;
-
-	WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
-	old_status = connector->status;
-
-	connector->status = connector->funcs->detect(connector, false);
-	if (old_status == connector->status)
-		return false;
-
-	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
-		      connector->base.id,
-		      connector->name,
-		      drm_get_connector_status_name(old_status),
-		      drm_get_connector_status_name(connector->status));
-
-	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, hotplug.dig_port_work);
-	u32 long_port_mask, short_port_mask;
-	struct intel_digital_port *intel_dig_port;
-	int i;
-	u32 old_bits = 0;
-
-	spin_lock_irq(&dev_priv->irq_lock);
-	long_port_mask = dev_priv->hotplug.long_port_mask;
-	dev_priv->hotplug.long_port_mask = 0;
-	short_port_mask = dev_priv->hotplug.short_port_mask;
-	dev_priv->hotplug.short_port_mask = 0;
-	spin_unlock_irq(&dev_priv->irq_lock);
-
-	for (i = 0; i < I915_MAX_PORTS; i++) {
-		bool valid = false;
-		bool long_hpd = false;
-		intel_dig_port = dev_priv->hotplug.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) {
-			enum irqreturn ret;
-
-			ret = intel_dig_port->hpd_pulse(intel_dig_port, long_hpd);
-			if (ret == IRQ_NONE) {
-				/* fall back to old school hpd */
-				old_bits |= (1 << intel_dig_port->base.hpd_pin);
-			}
-		}
-	}
-
-	if (old_bits) {
-		spin_lock_irq(&dev_priv->irq_lock);
-		dev_priv->hotplug.event_bits |= old_bits;
-		spin_unlock_irq(&dev_priv->irq_lock);
-		schedule_work(&dev_priv->hotplug.hotplug_work);
-	}
-}
-
-/*
- * Handle hotplug events outside the interrupt handler proper.
- */
-static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv);
-
-static void i915_hotplug_work_func(struct work_struct *work)
-{
-	struct drm_i915_private *dev_priv =
-		container_of(work, struct drm_i915_private, hotplug.hotplug_work);
-	struct drm_device *dev = dev_priv->dev;
-	struct drm_mode_config *mode_config = &dev->mode_config;
-	struct intel_connector *intel_connector;
-	struct intel_encoder *intel_encoder;
-	struct drm_connector *connector;
-	bool changed = false;
-	u32 hpd_event_bits;
-
-	mutex_lock(&mode_config->mutex);
-	DRM_DEBUG_KMS("running encoder hotplug functions\n");
-
-	spin_lock_irq(&dev_priv->irq_lock);
-
-	hpd_event_bits = dev_priv->hotplug.event_bits;
-	dev_priv->hotplug.event_bits = 0;
-
-	/* Disable hotplug on connectors that hit an irq storm. */
-	intel_hpd_irq_storm_disable(dev_priv);
-
-	spin_unlock_irq(&dev_priv->irq_lock);
-
-	list_for_each_entry(connector, &mode_config->connector_list, head) {
-		intel_connector = to_intel_connector(connector);
-		if (!intel_connector->encoder)
-			continue;
-		intel_encoder = intel_connector->encoder;
-		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
-			DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
-				      connector->name, intel_encoder->hpd_pin);
-			if (intel_encoder->hot_plug)
-				intel_encoder->hot_plug(intel_encoder);
-			if (intel_hpd_irq_event(dev, connector))
-				changed = true;
-		}
-	}
-	mutex_unlock(&mode_config->mutex);
-
-	if (changed)
-		drm_kms_helper_hotplug_event(dev);
-}
-
 static void ironlake_rps_change_irq_handler(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -1346,94 +1227,6 @@ static irqreturn_t gen8_gt_irq_handler(struct drm_i915_private *dev_priv,
 	return ret;
 }
 
-#define HPD_STORM_DETECT_PERIOD 1000
-#define HPD_STORM_THRESHOLD 5
-
-/**
- * intel_hpd_irq_storm_detect - gather stats and detect HPD irq storm on a pin
- * @dev_priv: private driver data pointer
- * @pin: the pin to gather stats on
- *
- * Gather stats about HPD irqs from the specified @pin, and detect irq
- * storms. Only the pin specific stats and state are changed, the caller is
- * responsible for further action.
- *
- * @HPD_STORM_THRESHOLD irqs are allowed within @HPD_STORM_DETECT_PERIOD ms,
- * otherwise it's considered an irq storm, and the irq state is set to
- * @HPD_MARK_DISABLED.
- *
- * Return true if an irq storm was detected on @pin.
- */
-static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
-				       enum hpd_pin pin)
-{
-	unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies;
-	unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
-	bool storm = false;
-
-	if (!time_in_range(jiffies, start, end)) {
-		dev_priv->hotplug.stats[pin].last_jiffies = jiffies;
-		dev_priv->hotplug.stats[pin].count = 0;
-		DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", pin);
-	} else if (dev_priv->hotplug.stats[pin].count > HPD_STORM_THRESHOLD) {
-		dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED;
-		DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);
-		storm = true;
-	} else {
-		dev_priv->hotplug.stats[pin].count++;
-		DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,
-			      dev_priv->hotplug.stats[pin].count);
-	}
-
-	return storm;
-}
-
-#define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
-
-static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)
-{
-	struct drm_device *dev = dev_priv->dev;
-	struct drm_mode_config *mode_config = &dev->mode_config;
-	struct intel_connector *intel_connector;
-	struct intel_encoder *intel_encoder;
-	struct drm_connector *connector;
-	enum hpd_pin pin;
-	bool hpd_disabled = false;
-
-	assert_spin_locked(&dev_priv->irq_lock);
-
-	list_for_each_entry(connector, &mode_config->connector_list, head) {
-		if (connector->polled != DRM_CONNECTOR_POLL_HPD)
-			continue;
-
-		intel_connector = to_intel_connector(connector);
-		intel_encoder = intel_connector->encoder;
-		if (!intel_encoder)
-			continue;
-
-		pin = intel_encoder->hpd_pin;
-		if (pin == HPD_NONE ||
-		    dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
-			continue;
-
-		DRM_INFO("HPD interrupt storm detected on connector %s: "
-			 "switching from hotplug detection to polling\n",
-			 connector->name);
-
-		dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
-		connector->polled = DRM_CONNECTOR_POLL_CONNECT
-			| DRM_CONNECTOR_POLL_DISCONNECT;
-		hpd_disabled = true;
-	}
-
-	/* Enable polling and queue hotplug re-enabling. */
-	if (hpd_disabled) {
-		drm_kms_helper_poll_enable(dev);
-		mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
-				 msecs_to_jiffies(I915_REENABLE_HOTPLUG_DELAY));
-	}
-}
-
 static bool pch_port_hotplug_long_detect(enum port port, u32 val)
 {
 	switch (port) {
@@ -1462,20 +1255,6 @@ static bool i9xx_port_hotplug_long_detect(enum port port, u32 val)
 	}
 }
 
-static 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 */
-	}
-}
-
 /* Get a bit mask of pins that have triggered, and which ones may be long. */
 static void pch_get_hpd_pins(u32 *pin_mask, u32 *long_mask,
 			     u32 hotplug_trigger, u32 dig_hotplug_reg, const u32 hpd[HPD_NUM_PINS])
@@ -1492,7 +1271,7 @@ static void pch_get_hpd_pins(u32 *pin_mask, u32 *long_mask,
 		if (hpd[i] & hotplug_trigger) {
 			*pin_mask |= BIT(i);
 
-			if (pch_port_hotplug_long_detect(get_port_from_pin(i), dig_hotplug_reg))
+			if (pch_port_hotplug_long_detect(intel_hpd_pin_to_port(i), dig_hotplug_reg))
 				*long_mask |= BIT(i);
 		}
 	}
@@ -1518,7 +1297,7 @@ static void i9xx_get_hpd_pins(u32 *pin_mask, u32 *long_mask,
 		if (hpd[i] & hotplug_trigger) {
 			*pin_mask |= BIT(i);
 
-			if (i9xx_port_hotplug_long_detect(get_port_from_pin(i), hotplug_trigger))
+			if (i9xx_port_hotplug_long_detect(intel_hpd_pin_to_port(i), hotplug_trigger))
 				*long_mask |= BIT(i);
 		}
 	}
@@ -1527,104 +1306,6 @@ static void i9xx_get_hpd_pins(u32 *pin_mask, u32 *long_mask,
 			 hotplug_trigger, *pin_mask);
 }
 
-/**
- * intel_hpd_irq_handler - main hotplug irq handler
- * @dev: drm device
- * @pin_mask: a mask of hpd pins that have triggered the irq
- * @long_mask: a mask of hpd pins that may be long hpd pulses
- *
- * This is the main hotplug irq handler for all platforms. The platform specific
- * irq handlers call the platform specific hotplug irq handlers, which read and
- * decode the appropriate registers into bitmasks about hpd pins that have
- * triggered (@pin_mask), and which of those pins may be long pulses
- * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
- * is not a digital port.
- *
- * Here, we do hotplug irq storm detection and mitigation, and pass further
- * processing to appropriate bottom halves.
- */
-static void intel_hpd_irq_handler(struct drm_device *dev,
-				  u32 pin_mask, u32 long_mask)
-{
-	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;
-	bool is_dig_port;
-
-	if (!pin_mask)
-		return;
-
-	spin_lock(&dev_priv->irq_lock);
-	for_each_hpd_pin(i) {
-		if (!(BIT(i) & pin_mask))
-			continue;
-
-		port = get_port_from_pin(i);
-		is_dig_port = port && dev_priv->hotplug.irq_port[port];
-
-		if (is_dig_port) {
-			bool long_hpd = long_mask & BIT(i);
-
-			DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
-					 long_hpd ? "long" : "short");
-			/*
-			 * For long HPD pulses we want to have the digital queue happen,
-			 * but we still want HPD storm detection to function.
-			 */
-			queue_dig = true;
-			if (long_hpd) {
-				dev_priv->hotplug.long_port_mask |= (1 << port);
-			} else {
-				/* for short HPD just trigger the digital queue */
-				dev_priv->hotplug.short_port_mask |= (1 << port);
-				continue;
-			}
-		}
-
-		if (dev_priv->hotplug.stats[i].state == HPD_DISABLED) {
-			/*
-			 * On GMCH platforms the interrupt mask bits only
-			 * prevent irq generation, not the setting of the
-			 * hotplug bits itself. So only WARN about unexpected
-			 * interrupts on saner platforms.
-			 */
-			WARN_ONCE(INTEL_INFO(dev)->gen >= 5 && !IS_VALLEYVIEW(dev),
-				  "Received HPD interrupt on pin %d although disabled\n", i);
-			continue;
-		}
-
-		if (dev_priv->hotplug.stats[i].state != HPD_ENABLED)
-			continue;
-
-		if (!is_dig_port) {
-			dev_priv->hotplug.event_bits |= BIT(i);
-			queue_hp = true;
-		}
-
-		if (intel_hpd_irq_storm_detect(dev_priv, i)) {
-			dev_priv->hotplug.event_bits &= ~BIT(i);
-			storm_detected = true;
-		}
-	}
-
-	if (storm_detected)
-		dev_priv->display.hpd_irq_setup(dev);
-	spin_unlock(&dev_priv->irq_lock);
-
-	/*
-	 * Our hotplug handler can grab modeset locks (by calling down into the
-	 * fb helpers). Hence it must not be run on our own dev-priv->wq work
-	 * queue for otherwise the flush_work in the pageflip code will
-	 * deadlock.
-	 */
-	if (queue_dig)
-		queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
-	if (queue_hp)
-		schedule_work(&dev_priv->hotplug.hotplug_work);
-}
-
 static void gmbus_irq_handler(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -4367,46 +4048,6 @@ static void i965_irq_uninstall(struct drm_device * dev)
 	I915_WRITE(IIR, I915_READ(IIR));
 }
 
-static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
-{
-	struct drm_i915_private *dev_priv =
-		container_of(work, typeof(*dev_priv),
-			     hotplug.reenable_work.work);
-	struct drm_device *dev = dev_priv->dev;
-	struct drm_mode_config *mode_config = &dev->mode_config;
-	int i;
-
-	intel_runtime_pm_get(dev_priv);
-
-	spin_lock_irq(&dev_priv->irq_lock);
-	for_each_hpd_pin(i) {
-		struct drm_connector *connector;
-
-		if (dev_priv->hotplug.stats[i].state != HPD_DISABLED)
-			continue;
-
-		dev_priv->hotplug.stats[i].state = HPD_ENABLED;
-
-		list_for_each_entry(connector, &mode_config->connector_list, head) {
-			struct intel_connector *intel_connector = to_intel_connector(connector);
-
-			if (intel_connector->encoder->hpd_pin == i) {
-				if (connector->polled != intel_connector->polled)
-					DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
-							 connector->name);
-				connector->polled = intel_connector->polled;
-				if (!connector->polled)
-					connector->polled = DRM_CONNECTOR_POLL_HPD;
-			}
-		}
-	}
-	if (dev_priv->display.hpd_irq_setup)
-		dev_priv->display.hpd_irq_setup(dev);
-	spin_unlock_irq(&dev_priv->irq_lock);
-
-	intel_runtime_pm_put(dev_priv);
-}
-
 /**
  * intel_irq_init - initializes irq support
  * @dev_priv: i915 device instance
@@ -4418,8 +4059,8 @@ void intel_irq_init(struct drm_i915_private *dev_priv)
 {
 	struct drm_device *dev = dev_priv->dev;
 
-	INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
-	INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
+	intel_hpd_init_work(dev_priv);
+
 	INIT_WORK(&dev_priv->rps.work, gen6_pm_rps_work);
 	INIT_WORK(&dev_priv->l3_parity.error_work, ivybridge_parity_work);
 
@@ -4432,8 +4073,6 @@ void intel_irq_init(struct drm_i915_private *dev_priv)
 
 	INIT_DELAYED_WORK(&dev_priv->gpu_error.hangcheck_work,
 			  i915_hangcheck_elapsed);
-	INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
-			  intel_hpd_irq_storm_reenable_work);
 
 	pm_qos_add_request(&dev_priv->pm_qos, PM_QOS_CPU_DMA_LATENCY, PM_QOS_DEFAULT_VALUE);
 
@@ -4519,46 +4158,6 @@ void intel_irq_init(struct drm_i915_private *dev_priv)
 }
 
 /**
- * intel_hpd_init - initializes and enables hpd support
- * @dev_priv: i915 device instance
- *
- * This function enables the hotplug support. It requires that interrupts have
- * already been enabled with intel_irq_init_hw(). From this point on hotplug and
- * poll request can run concurrently to other code, so locking rules must be
- * obeyed.
- *
- * This is a separate step from interrupt enabling to simplify the locking rules
- * in the driver load and resume code.
- */
-void intel_hpd_init(struct drm_i915_private *dev_priv)
-{
-	struct drm_device *dev = dev_priv->dev;
-	struct drm_mode_config *mode_config = &dev->mode_config;
-	struct drm_connector *connector;
-	int i;
-
-	for_each_hpd_pin(i) {
-		dev_priv->hotplug.stats[i].count = 0;
-		dev_priv->hotplug.stats[i].state = HPD_ENABLED;
-	}
-	list_for_each_entry(connector, &mode_config->connector_list, head) {
-		struct intel_connector *intel_connector = to_intel_connector(connector);
-		connector->polled = intel_connector->polled;
-		if (connector->encoder && !connector->polled && I915_HAS_HOTPLUG(dev) && intel_connector->encoder->hpd_pin > HPD_NONE)
-			connector->polled = DRM_CONNECTOR_POLL_HPD;
-		if (intel_connector->mst_port)
-			connector->polled = DRM_CONNECTOR_POLL_HPD;
-	}
-
-	/* Interrupt setup is already guaranteed to be single-threaded, this is
-	 * just to make the assert_spin_locked checks happy. */
-	spin_lock_irq(&dev_priv->irq_lock);
-	if (dev_priv->display.hpd_irq_setup)
-		dev_priv->display.hpd_irq_setup(dev);
-	spin_unlock_irq(&dev_priv->irq_lock);
-}
-
-/**
  * intel_irq_install - enables the hardware interrupt
  * @dev_priv: i915 device instance
  *
diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c
new file mode 100644
index 000000000000..3c53aac71d98
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_hotplug.c
@@ -0,0 +1,452 @@
+/*
+ * Copyright © 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/kernel.h>
+
+#include <drm/drmP.h>
+#include <drm/i915_drm.h>
+
+#include "i915_drv.h"
+#include "intel_drv.h"
+
+enum port intel_hpd_pin_to_port(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 */
+	}
+}
+
+#define HPD_STORM_DETECT_PERIOD		1000
+#define HPD_STORM_THRESHOLD		5
+#define HPD_STORM_REENABLE_DELAY	(2 * 60 * 1000)
+
+/**
+ * intel_hpd_irq_storm_detect - gather stats and detect HPD irq storm on a pin
+ * @dev_priv: private driver data pointer
+ * @pin: the pin to gather stats on
+ *
+ * Gather stats about HPD irqs from the specified @pin, and detect irq
+ * storms. Only the pin specific stats and state are changed, the caller is
+ * responsible for further action.
+ *
+ * @HPD_STORM_THRESHOLD irqs are allowed within @HPD_STORM_DETECT_PERIOD ms,
+ * otherwise it's considered an irq storm, and the irq state is set to
+ * @HPD_MARK_DISABLED.
+ *
+ * Return true if an irq storm was detected on @pin.
+ */
+static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,
+				       enum hpd_pin pin)
+{
+	unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies;
+	unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
+	bool storm = false;
+
+	if (!time_in_range(jiffies, start, end)) {
+		dev_priv->hotplug.stats[pin].last_jiffies = jiffies;
+		dev_priv->hotplug.stats[pin].count = 0;
+		DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", pin);
+	} else if (dev_priv->hotplug.stats[pin].count > HPD_STORM_THRESHOLD) {
+		dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED;
+		DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);
+		storm = true;
+	} else {
+		dev_priv->hotplug.stats[pin].count++;
+		DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,
+			      dev_priv->hotplug.stats[pin].count);
+	}
+
+	return storm;
+}
+
+static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)
+{
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct intel_connector *intel_connector;
+	struct intel_encoder *intel_encoder;
+	struct drm_connector *connector;
+	enum hpd_pin pin;
+	bool hpd_disabled = false;
+
+	assert_spin_locked(&dev_priv->irq_lock);
+
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		if (connector->polled != DRM_CONNECTOR_POLL_HPD)
+			continue;
+
+		intel_connector = to_intel_connector(connector);
+		intel_encoder = intel_connector->encoder;
+		if (!intel_encoder)
+			continue;
+
+		pin = intel_encoder->hpd_pin;
+		if (pin == HPD_NONE ||
+		    dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)
+			continue;
+
+		DRM_INFO("HPD interrupt storm detected on connector %s: "
+			 "switching from hotplug detection to polling\n",
+			 connector->name);
+
+		dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
+		connector->polled = DRM_CONNECTOR_POLL_CONNECT
+			| DRM_CONNECTOR_POLL_DISCONNECT;
+		hpd_disabled = true;
+	}
+
+	/* Enable polling and queue hotplug re-enabling. */
+	if (hpd_disabled) {
+		drm_kms_helper_poll_enable(dev);
+		mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
+				 msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
+	}
+}
+
+static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(work, typeof(*dev_priv),
+			     hotplug.reenable_work.work);
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	int i;
+
+	intel_runtime_pm_get(dev_priv);
+
+	spin_lock_irq(&dev_priv->irq_lock);
+	for_each_hpd_pin(i) {
+		struct drm_connector *connector;
+
+		if (dev_priv->hotplug.stats[i].state != HPD_DISABLED)
+			continue;
+
+		dev_priv->hotplug.stats[i].state = HPD_ENABLED;
+
+		list_for_each_entry(connector, &mode_config->connector_list, head) {
+			struct intel_connector *intel_connector = to_intel_connector(connector);
+
+			if (intel_connector->encoder->hpd_pin == i) {
+				if (connector->polled != intel_connector->polled)
+					DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
+							 connector->name);
+				connector->polled = intel_connector->polled;
+				if (!connector->polled)
+					connector->polled = DRM_CONNECTOR_POLL_HPD;
+			}
+		}
+	}
+	if (dev_priv->display.hpd_irq_setup)
+		dev_priv->display.hpd_irq_setup(dev);
+	spin_unlock_irq(&dev_priv->irq_lock);
+
+	intel_runtime_pm_put(dev_priv);
+}
+
+static bool intel_hpd_irq_event(struct drm_device *dev,
+				struct drm_connector *connector)
+{
+	enum drm_connector_status old_status;
+
+	WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
+	old_status = connector->status;
+
+	connector->status = connector->funcs->detect(connector, false);
+	if (old_status == connector->status)
+		return false;
+
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
+		      connector->base.id,
+		      connector->name,
+		      drm_get_connector_status_name(old_status),
+		      drm_get_connector_status_name(connector->status));
+
+	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, hotplug.dig_port_work);
+	u32 long_port_mask, short_port_mask;
+	struct intel_digital_port *intel_dig_port;
+	int i;
+	u32 old_bits = 0;
+
+	spin_lock_irq(&dev_priv->irq_lock);
+	long_port_mask = dev_priv->hotplug.long_port_mask;
+	dev_priv->hotplug.long_port_mask = 0;
+	short_port_mask = dev_priv->hotplug.short_port_mask;
+	dev_priv->hotplug.short_port_mask = 0;
+	spin_unlock_irq(&dev_priv->irq_lock);
+
+	for (i = 0; i < I915_MAX_PORTS; i++) {
+		bool valid = false;
+		bool long_hpd = false;
+		intel_dig_port = dev_priv->hotplug.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) {
+			enum irqreturn ret;
+
+			ret = intel_dig_port->hpd_pulse(intel_dig_port, long_hpd);
+			if (ret == IRQ_NONE) {
+				/* fall back to old school hpd */
+				old_bits |= (1 << intel_dig_port->base.hpd_pin);
+			}
+		}
+	}
+
+	if (old_bits) {
+		spin_lock_irq(&dev_priv->irq_lock);
+		dev_priv->hotplug.event_bits |= old_bits;
+		spin_unlock_irq(&dev_priv->irq_lock);
+		schedule_work(&dev_priv->hotplug.hotplug_work);
+	}
+}
+
+/*
+ * Handle hotplug events outside the interrupt handler proper.
+ */
+static void i915_hotplug_work_func(struct work_struct *work)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(work, struct drm_i915_private, hotplug.hotplug_work);
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct intel_connector *intel_connector;
+	struct intel_encoder *intel_encoder;
+	struct drm_connector *connector;
+	bool changed = false;
+	u32 hpd_event_bits;
+
+	mutex_lock(&mode_config->mutex);
+	DRM_DEBUG_KMS("running encoder hotplug functions\n");
+
+	spin_lock_irq(&dev_priv->irq_lock);
+
+	hpd_event_bits = dev_priv->hotplug.event_bits;
+	dev_priv->hotplug.event_bits = 0;
+
+	/* Disable hotplug on connectors that hit an irq storm. */
+	intel_hpd_irq_storm_disable(dev_priv);
+
+	spin_unlock_irq(&dev_priv->irq_lock);
+
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		intel_connector = to_intel_connector(connector);
+		if (!intel_connector->encoder)
+			continue;
+		intel_encoder = intel_connector->encoder;
+		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
+			DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",
+				      connector->name, intel_encoder->hpd_pin);
+			if (intel_encoder->hot_plug)
+				intel_encoder->hot_plug(intel_encoder);
+			if (intel_hpd_irq_event(dev, connector))
+				changed = true;
+		}
+	}
+	mutex_unlock(&mode_config->mutex);
+
+	if (changed)
+		drm_kms_helper_hotplug_event(dev);
+}
+
+
+/**
+ * intel_hpd_irq_handler - main hotplug irq handler
+ * @dev: drm device
+ * @pin_mask: a mask of hpd pins that have triggered the irq
+ * @long_mask: a mask of hpd pins that may be long hpd pulses
+ *
+ * This is the main hotplug irq handler for all platforms. The platform specific
+ * irq handlers call the platform specific hotplug irq handlers, which read and
+ * decode the appropriate registers into bitmasks about hpd pins that have
+ * triggered (@pin_mask), and which of those pins may be long pulses
+ * (@long_mask). The @long_mask is ignored if the port corresponding to the pin
+ * is not a digital port.
+ *
+ * Here, we do hotplug irq storm detection and mitigation, and pass further
+ * processing to appropriate bottom halves.
+ */
+void intel_hpd_irq_handler(struct drm_device *dev,
+			   u32 pin_mask, u32 long_mask)
+{
+	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;
+	bool is_dig_port;
+
+	if (!pin_mask)
+		return;
+
+	spin_lock(&dev_priv->irq_lock);
+	for_each_hpd_pin(i) {
+		if (!(BIT(i) & pin_mask))
+			continue;
+
+		port = intel_hpd_pin_to_port(i);
+		is_dig_port = port && dev_priv->hotplug.irq_port[port];
+
+		if (is_dig_port) {
+			bool long_hpd = long_mask & BIT(i);
+
+			DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
+					 long_hpd ? "long" : "short");
+			/*
+			 * For long HPD pulses we want to have the digital queue happen,
+			 * but we still want HPD storm detection to function.
+			 */
+			queue_dig = true;
+			if (long_hpd) {
+				dev_priv->hotplug.long_port_mask |= (1 << port);
+			} else {
+				/* for short HPD just trigger the digital queue */
+				dev_priv->hotplug.short_port_mask |= (1 << port);
+				continue;
+			}
+		}
+
+		if (dev_priv->hotplug.stats[i].state == HPD_DISABLED) {
+			/*
+			 * On GMCH platforms the interrupt mask bits only
+			 * prevent irq generation, not the setting of the
+			 * hotplug bits itself. So only WARN about unexpected
+			 * interrupts on saner platforms.
+			 */
+			WARN_ONCE(INTEL_INFO(dev)->gen >= 5 && !IS_VALLEYVIEW(dev),
+				  "Received HPD interrupt on pin %d although disabled\n", i);
+			continue;
+		}
+
+		if (dev_priv->hotplug.stats[i].state != HPD_ENABLED)
+			continue;
+
+		if (!is_dig_port) {
+			dev_priv->hotplug.event_bits |= BIT(i);
+			queue_hp = true;
+		}
+
+		if (intel_hpd_irq_storm_detect(dev_priv, i)) {
+			dev_priv->hotplug.event_bits &= ~BIT(i);
+			storm_detected = true;
+		}
+	}
+
+	if (storm_detected)
+		dev_priv->display.hpd_irq_setup(dev);
+	spin_unlock(&dev_priv->irq_lock);
+
+	/*
+	 * Our hotplug handler can grab modeset locks (by calling down into the
+	 * fb helpers). Hence it must not be run on our own dev-priv->wq work
+	 * queue for otherwise the flush_work in the pageflip code will
+	 * deadlock.
+	 */
+	if (queue_dig)
+		queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);
+	if (queue_hp)
+		schedule_work(&dev_priv->hotplug.hotplug_work);
+}
+
+/**
+ * intel_hpd_init - initializes and enables hpd support
+ * @dev_priv: i915 device instance
+ *
+ * This function enables the hotplug support. It requires that interrupts have
+ * already been enabled with intel_irq_init_hw(). From this point on hotplug and
+ * poll request can run concurrently to other code, so locking rules must be
+ * obeyed.
+ *
+ * This is a separate step from interrupt enabling to simplify the locking rules
+ * in the driver load and resume code.
+ */
+void intel_hpd_init(struct drm_i915_private *dev_priv)
+{
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct drm_connector *connector;
+	int i;
+
+	for_each_hpd_pin(i) {
+		dev_priv->hotplug.stats[i].count = 0;
+		dev_priv->hotplug.stats[i].state = HPD_ENABLED;
+	}
+	list_for_each_entry(connector, &mode_config->connector_list, head) {
+		struct intel_connector *intel_connector = to_intel_connector(connector);
+		connector->polled = intel_connector->polled;
+		if (connector->encoder && !connector->polled && I915_HAS_HOTPLUG(dev) && intel_connector->encoder->hpd_pin > HPD_NONE)
+			connector->polled = DRM_CONNECTOR_POLL_HPD;
+		if (intel_connector->mst_port)
+			connector->polled = DRM_CONNECTOR_POLL_HPD;
+	}
+
+	/*
+	 * Interrupt setup is already guaranteed to be single-threaded, this is
+	 * just to make the assert_spin_locked checks happy.
+	 */
+	spin_lock_irq(&dev_priv->irq_lock);
+	if (dev_priv->display.hpd_irq_setup)
+		dev_priv->display.hpd_irq_setup(dev);
+	spin_unlock_irq(&dev_priv->irq_lock);
+}
+
+void intel_hpd_init_work(struct drm_i915_private *dev_priv)
+{
+	INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
+	INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
+	INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
+			  intel_hpd_irq_storm_reenable_work);
+}
+
+void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
+{
+	spin_lock_irq(&dev_priv->irq_lock);
+
+	dev_priv->hotplug.long_port_mask = 0;
+	dev_priv->hotplug.short_port_mask = 0;
+	dev_priv->hotplug.event_bits = 0;
+
+	spin_unlock_irq(&dev_priv->irq_lock);
+
+	cancel_work_sync(&dev_priv->hotplug.dig_port_work);
+	cancel_work_sync(&dev_priv->hotplug.hotplug_work);
+	cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
+}