/*
* 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"
/**
* DOC: Hotplug
*
* Simply put, hotplug occurs when a display is connected to or disconnected
* from the system. However, there may be adapters and docking stations and
* Display Port short pulses and MST devices involved, complicating matters.
*
* Hotplug in i915 is handled in many different levels of abstraction.
*
* The platform dependent interrupt handling code in i915_irq.c enables,
* disables, and does preliminary handling of the interrupts. The interrupt
* handlers gather the hotplug detect (HPD) information from relevant registers
* into a platform independent mask of hotplug pins that have fired.
*
* The platform independent interrupt handler intel_hpd_irq_handler() in
* intel_hotplug.c does hotplug irq storm detection and mitigation, and passes
* further processing to appropriate bottom halves (Display Port specific and
* regular hotplug).
*
* The Display Port work function i915_digport_work_func() calls into
* intel_dp_hpd_pulse() via hooks, which handles DP short pulses and DP MST long
* pulses, with failures and non-MST long pulses triggering regular hotplug
* processing on the connector.
*
* The regular hotplug work function i915_hotplug_work_func() calls connector
* detect hooks, and, if connector status changes, triggers sending of hotplug
* uevent to userspace via drm_kms_helper_hotplug_event().
*
* Finally, the userspace is responsible for triggering a modeset upon receiving
* the hotplug uevent, disabling or enabling the crtc as needed.
*
* The hotplug interrupt storm detection and mitigation code keeps track of the
* number of interrupts per hotplug pin per a period of time, and if the number
* of interrupts exceeds a certain threshold, the interrupt is disabled for a
* while before being re-enabled. The intention is to mitigate issues raising
* from broken hardware triggering massive amounts of interrupts and grinding
* the system to a halt.
*
* Current implementation expects that hotplug interrupt storm will not be
* seen when display port sink is connected, hence on platforms whose DP
* callback is handled by i915_digport_work_func reenabling of hpd is not
* performed (it was never expected to be disabled in the first place ;) )
* this is specific to DP sinks handled by this routine and any other display
* such as HDMI or DVI enabled on the same port will have proper logic since
* it will use i915_hotplug_work_func where this logic is handled.
*/
bool intel_hpd_pin_to_port(enum hpd_pin pin, enum port *port)
{
switch (pin) {
case HPD_PORT_A:
*port = PORT_A;
return true;
case HPD_PORT_B:
*port = PORT_B;
return true;
case HPD_PORT_C:
*port = PORT_C;
return true;
case HPD_PORT_D:
*port = PORT_D;
return true;
case HPD_PORT_E:
*port = PORT_E;
return true;
default:
return false; /* 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_locked(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;
is_dig_port = intel_hpd_pin_to_port(i, &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(!HAS_GMCH_DISPLAY(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);
}
