drm/i915: move generic hotplug code into new intel_hotplug.c file
authorJani Nikula <jani.nikula@intel.com>
Thu, 18 Jun 2015 10:06:16 +0000 (13:06 +0300)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Mon, 22 Jun 2015 13:03:42 +0000 (15:03 +0200)
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>
drivers/gpu/drm/i915/Makefile
drivers/gpu/drm/i915/i915_drv.c
drivers/gpu/drm/i915/i915_drv.h
drivers/gpu/drm/i915/i915_irq.c
drivers/gpu/drm/i915/intel_hotplug.c [new file with mode: 0644]

index b7ddf48e1d758de11771ed3e6910e06a8a69cb60..de2196543367683f988b08afb6826a6f493d244e 100644 (file)
@@ -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
index 78ef0bb53c36a51b25a23df2082e3f1693ce543a..0ec57bad454fb9639acb3bd2064178f7fe5a7864 100644 (file)
@@ -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);
index 3e36af90f94305eb3999000bb4f2931cd9d8c116..c3b9fcf301a07e41c77232dd1b8437dc52252e0c 100644 (file)
@@ -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);
 
index ce9eef5f722cabc61d4dcb4d3be4b7a5331f9936..2d3b2ccf9ce4cd02d96d5e54f8429a0731469b5b 100644 (file)
@@ -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);
 
@@ -4518,46 +4157,6 @@ 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 (file)
index 0000000..3c53aac
--- /dev/null
@@ -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);
+}