// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   *  dock.c - ACPI dock station driver
   *

   *  Copyright (C) 2006, 2014, Intel Corp.
   *  Author: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
   *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>

   */
  
  #include <linux/kernel.h>

  #include <linux/moduleparam.h>

  #include <linux/slab.h>

  #include <linux/init.h>
  #include <linux/types.h>
  #include <linux/notifier.h>

  #include <linux/platform_device.h>

  #include <linux/jiffies.h>

  #include <linux/stddef.h>

  #include <linux/acpi.h>

  #include "internal.h"

  static bool immediate_undock = 1;

  module_param(immediate_undock, bool, 0644);
  MODULE_PARM_DESC(immediate_undock, "1 (default) will cause the driver to "
  	"undock immediately when the undock button is pressed, 0 will cause"
  	" the driver to wait for userspace to write the undock sysfs file "
  	" before undocking");

  struct dock_station {
  	acpi_handle handle;
  	unsigned long last_dock_time;
  	u32 flags;

  	struct list_head dependent_devices;

  	struct list_head sibling;

  	struct platform_device *dock_device;

  };

  static LIST_HEAD(dock_stations);
  static int dock_station_count;

  
  struct dock_dependent_device {
  	struct list_head list;

  	struct acpi_device *adev;

  };
  
  #define DOCK_DOCKING	0x00000001

  #define DOCK_UNDOCKING  0x00000002

  #define DOCK_IS_DOCK	0x00000010
  #define DOCK_IS_ATA	0x00000020
  #define DOCK_IS_BAT	0x00000040

  #define DOCK_EVENT	3
  #define UNDOCK_EVENT	2

  enum dock_callback_type {
  	DOCK_CALL_HANDLER,
  	DOCK_CALL_FIXUP,
  	DOCK_CALL_UEVENT,
  };

  /*****************************************************************************
   *                         Dock Dependent device functions                   *
   *****************************************************************************/
  /**

   * add_dock_dependent_device - associate a device with the dock station

   * @ds: Dock station.
   * @adev: Dependent ACPI device object.

   *

   * Add the dependent device to the dock's dependent device list.

   */

  static int add_dock_dependent_device(struct dock_station *ds,
  				     struct acpi_device *adev)

  {
  	struct dock_dependent_device *dd;
  
  	dd = kzalloc(sizeof(*dd), GFP_KERNEL);

  	if (!dd)
  		return -ENOMEM;

  	dd->adev = adev;

  	INIT_LIST_HEAD(&dd->list);

  	list_add_tail(&dd->list, &ds->dependent_devices);

  
  	return 0;

  }

  static void dock_hotplug_event(struct dock_dependent_device *dd, u32 event,

  			       enum dock_callback_type cb_type)

  {

  	struct acpi_device *adev = dd->adev;

  	acpi_lock_hp_context();
  
  	if (!adev->hp)

  		goto out;

  
  	if (cb_type == DOCK_CALL_FIXUP) {
  		void (*fixup)(struct acpi_device *);
  
  		fixup = adev->hp->fixup;
  		if (fixup) {
  			acpi_unlock_hp_context();
  			fixup(adev);
  			return;
  		}

  	} else if (cb_type == DOCK_CALL_UEVENT) {
  		void (*uevent)(struct acpi_device *, u32);
  
  		uevent = adev->hp->uevent;
  		if (uevent) {
  			acpi_unlock_hp_context();
  			uevent(adev, event);
  			return;
  		}

  	} else {
  		int (*notify)(struct acpi_device *, u32);

  		notify = adev->hp->notify;

  		if (notify) {
  			acpi_unlock_hp_context();
  			notify(adev, event);
  			return;
  		}
  	}

   out:

  	acpi_unlock_hp_context();

  }

  static struct dock_station *find_dock_station(acpi_handle handle)
  {
  	struct dock_station *ds;
  
  	list_for_each_entry(ds, &dock_stations, sibling)
  		if (ds->handle == handle)
  			return ds;
  
  	return NULL;
  }

  /**
   * find_dock_dependent_device - get a device dependent on this dock
   * @ds: the dock station

   * @adev: ACPI device object to find.

   *
   * iterate over the dependent device list for this dock.  If the
   * dependent device matches the handle, return.
   */
  static struct dock_dependent_device *

  find_dock_dependent_device(struct dock_station *ds, struct acpi_device *adev)

  {
  	struct dock_dependent_device *dd;

  	list_for_each_entry(dd, &ds->dependent_devices, list)

  		if (adev == dd->adev)

  			return dd;

  	return NULL;
  }

  void register_dock_dependent_device(struct acpi_device *adev,
  				    acpi_handle dshandle)

  {

  	struct dock_station *ds = find_dock_station(dshandle);

  	if (ds && !find_dock_dependent_device(ds, adev))
  		add_dock_dependent_device(ds, adev);

  }

  /*****************************************************************************
   *                         Dock functions                                    *
   *****************************************************************************/

  /**
   * is_dock_device - see if a device is on a dock station

   * @adev: ACPI device object to check.

   *
   * If this device is either the dock station itself,
   * or is a device dependent on the dock station, then it
   * is a dock device
   */

  int is_dock_device(struct acpi_device *adev)

  {

  	struct dock_station *dock_station;
  
  	if (!dock_station_count)

  		return 0;

  	if (acpi_dock_match(adev->handle))

  		return 1;

  
  	list_for_each_entry(dock_station, &dock_stations, sibling)

  		if (find_dock_dependent_device(dock_station, adev))

  			return 1;

  
  	return 0;
  }

  EXPORT_SYMBOL_GPL(is_dock_device);
  
  /**
   * dock_present - see if the dock station is present.
   * @ds: the dock station
   *
   * execute the _STA method.  note that present does not
   * imply that we are docked.
   */
  static int dock_present(struct dock_station *ds)
  {

  	unsigned long long sta;

  	acpi_status status;
  
  	if (ds) {
  		status = acpi_evaluate_integer(ds->handle, "_STA", NULL, &sta);
  		if (ACPI_SUCCESS(status) && sta)
  			return 1;
  	}
  	return 0;
  }

  /**

   * hot_remove_dock_devices - Remove dock station devices.
   * @ds: Dock station.
   */
  static void hot_remove_dock_devices(struct dock_station *ds)
  {
  	struct dock_dependent_device *dd;
  
  	/*
  	 * Walk the list in reverse order so that devices that have been added
  	 * last are removed first (in case there are some indirect dependencies
  	 * between them).
  	 */
  	list_for_each_entry_reverse(dd, &ds->dependent_devices, list)

  		dock_hotplug_event(dd, ACPI_NOTIFY_EJECT_REQUEST,
  				   DOCK_CALL_HANDLER);

  
  	list_for_each_entry_reverse(dd, &ds->dependent_devices, list)

  		acpi_bus_trim(dd->adev);

  }
  
  /**
   * hotplug_dock_devices - Insert devices on a dock station.

   * @ds: the dock station

   * @event: either bus check or device check request

   *
   * Some devices on the dock station need to have drivers called
   * to perform hotplug operations after a dock event has occurred.
   * Traverse the list of dock devices that have registered a
   * hotplug handler, and call the handler.
   */
  static void hotplug_dock_devices(struct dock_station *ds, u32 event)
  {
  	struct dock_dependent_device *dd;

  	/* Call driver specific post-dock fixups. */
  	list_for_each_entry(dd, &ds->dependent_devices, list)
  		dock_hotplug_event(dd, event, DOCK_CALL_FIXUP);

  	/* Call driver specific hotplug functions. */

  	list_for_each_entry(dd, &ds->dependent_devices, list)

  		dock_hotplug_event(dd, event, DOCK_CALL_HANDLER);

  
  	/*

  	 * Check if all devices have been enumerated already.  If not, run
  	 * acpi_bus_scan() for them and that will cause scan handlers to be
  	 * attached to device objects or acpi_drivers to be stopped/started if
  	 * they are present.

  	 */

  	list_for_each_entry(dd, &ds->dependent_devices, list) {
  		struct acpi_device *adev = dd->adev;
  
  		if (!acpi_device_enumerated(adev)) {
  			int ret = acpi_bus_scan(adev->handle);
  			if (ret)
  				dev_dbg(&adev->dev, "scan error %d
  ", -ret);
  		}
  	}

  }
  
  static void dock_event(struct dock_station *ds, u32 event, int num)
  {

  	struct device *dev = &ds->dock_device->dev;

  	char event_string[13];

  	char *envp[] = { event_string, NULL };

  	struct dock_dependent_device *dd;

  
  	if (num == UNDOCK_EVENT)

  		sprintf(event_string, "EVENT=undock");

  	else

  		sprintf(event_string, "EVENT=dock");

  	/*

  	 * Indicate that the status of the dock station has
  	 * changed.

  	 */

  	if (num == DOCK_EVENT)
  		kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);

  	list_for_each_entry(dd, &ds->dependent_devices, list)

  		dock_hotplug_event(dd, event, DOCK_CALL_UEVENT);

  	if (num != DOCK_EVENT)
  		kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);

  }
  
  /**

   * handle_dock - handle a dock event
   * @ds: the dock station
   * @dock: to dock, or undock - that is the question
   *
   * Execute the _DCK method in response to an acpi event
   */
  static void handle_dock(struct dock_station *ds, int dock)
  {
  	acpi_status status;
  	struct acpi_object_list arg_list;
  	union acpi_object arg;

  	unsigned long long value;

  	acpi_handle_info(ds->handle, "%s
  ", dock ? "docking" : "undocking");

  
  	/* _DCK method has one argument */
  	arg_list.count = 1;
  	arg_list.pointer = &arg;
  	arg.type = ACPI_TYPE_INTEGER;
  	arg.integer.value = dock;

  	status = acpi_evaluate_integer(ds->handle, "_DCK", &arg_list, &value);

  	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)

  		acpi_handle_err(ds->handle, "Failed to execute _DCK (0x%x)
  ",
  				status);

  }
  
  static inline void dock(struct dock_station *ds)
  {
  	handle_dock(ds, 1);
  }
  
  static inline void undock(struct dock_station *ds)
  {
  	handle_dock(ds, 0);
  }
  
  static inline void begin_dock(struct dock_station *ds)
  {
  	ds->flags |= DOCK_DOCKING;
  }
  
  static inline void complete_dock(struct dock_station *ds)
  {
  	ds->flags &= ~(DOCK_DOCKING);
  	ds->last_dock_time = jiffies;
  }

  static inline void begin_undock(struct dock_station *ds)
  {
  	ds->flags |= DOCK_UNDOCKING;
  }
  
  static inline void complete_undock(struct dock_station *ds)
  {
  	ds->flags &= ~(DOCK_UNDOCKING);
  }

  /**
   * dock_in_progress - see if we are in the middle of handling a dock event
   * @ds: the dock station
   *
   * Sometimes while docking, false dock events can be sent to the driver
   * because good connections aren't made or some other reason.  Ignore these
   * if we are in the middle of doing something.
   */
  static int dock_in_progress(struct dock_station *ds)
  {
  	if ((ds->flags & DOCK_DOCKING) ||
  	    time_before(jiffies, (ds->last_dock_time + HZ)))
  		return 1;
  	return 0;
  }
  
  /**

   * handle_eject_request - handle an undock request checking for error conditions
   *
   * Check to make sure the dock device is still present, then undock and
   * hotremove all the devices that may need removing.
   */
  static int handle_eject_request(struct dock_station *ds, u32 event)
  {

  	if (dock_in_progress(ds))
  		return -EBUSY;
  
  	/*
  	 * here we need to generate the undock
  	 * event prior to actually doing the undock
  	 * so that the device struct still exists.

  	 * Also, even send the dock event if the
  	 * device is not present anymore

  	 */
  	dock_event(ds, event, UNDOCK_EVENT);

  	hot_remove_dock_devices(ds);

  	undock(ds);

  	acpi_evaluate_lck(ds->handle, 0);
  	acpi_evaluate_ej0(ds->handle);

  	if (dock_present(ds)) {

  		acpi_handle_err(ds->handle, "Unable to undock!
  ");

  		return -EBUSY;
  	}

  	complete_undock(ds);

  	return 0;
  }
  
  /**

   * dock_notify - Handle ACPI dock notification.
   * @adev: Dock station's ACPI device object.
   * @event: Event code.

   *
   * If we are notified to dock, then check to see if the dock is
   * present and then dock.  Notify all drivers of the dock event,

   * and then hotplug and devices that may need hotplugging.

   */

  int dock_notify(struct acpi_device *adev, u32 event)

  {

  	acpi_handle handle = adev->handle;
  	struct dock_station *ds = find_dock_station(handle);

  	int surprise_removal = 0;

  	if (!ds)
  		return -ENODEV;

  	/*
  	 * According to acpi spec 3.0a, if a DEVICE_CHECK notification
  	 * is sent and _DCK is present, it is assumed to mean an undock
  	 * request.
  	 */
  	if ((ds->flags & DOCK_IS_DOCK) && event == ACPI_NOTIFY_DEVICE_CHECK)
  		event = ACPI_NOTIFY_EJECT_REQUEST;
  
  	/*
  	 * dock station: BUS_CHECK - docked or surprise removal
  	 *		 DEVICE_CHECK - undocked
  	 * other device: BUS_CHECK/DEVICE_CHECK - added or surprise removal
  	 *
  	 * To simplify event handling, dock dependent device handler always
  	 * get ACPI_NOTIFY_BUS_CHECK/ACPI_NOTIFY_DEVICE_CHECK for add and
  	 * ACPI_NOTIFY_EJECT_REQUEST for removal
  	 */

  	switch (event) {
  	case ACPI_NOTIFY_BUS_CHECK:

  	case ACPI_NOTIFY_DEVICE_CHECK:

  		if (!dock_in_progress(ds) && !acpi_device_enumerated(adev)) {

  			begin_dock(ds);
  			dock(ds);
  			if (!dock_present(ds)) {

  				acpi_handle_err(handle, "Unable to dock!
  ");

  				complete_dock(ds);

  				break;
  			}

  			hotplug_dock_devices(ds, event);
  			complete_dock(ds);
  			dock_event(ds, event, DOCK_EVENT);

  			acpi_evaluate_lck(ds->handle, 1);

  			acpi_update_all_gpes();

  			break;

  		}

  		if (dock_present(ds) || dock_in_progress(ds))
  			break;
  		/* This is a surprise removal */
  		surprise_removal = 1;
  		event = ACPI_NOTIFY_EJECT_REQUEST;
  		/* Fall back */

  		fallthrough;

  	case ACPI_NOTIFY_EJECT_REQUEST:

  		begin_undock(ds);

  		if ((immediate_undock && !(ds->flags & DOCK_IS_ATA))
  		   || surprise_removal)

  			handle_eject_request(ds, event);
  		else
  			dock_event(ds, event, UNDOCK_EVENT);

  		break;

  	}

  	return 0;

  }

  /*
   * show_docked - read method for "docked" file in sysfs
   */
  static ssize_t show_docked(struct device *dev,
  			   struct device_attribute *attr, char *buf)
  {

  	struct dock_station *dock_station = dev->platform_data;

  	struct acpi_device *adev = NULL;

  	acpi_bus_get_device(dock_station->handle, &adev);
  	return snprintf(buf, PAGE_SIZE, "%u
  ", acpi_device_enumerated(adev));

  }

  static DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL);

  
  /*

   * show_flags - read method for flags file in sysfs
   */
  static ssize_t show_flags(struct device *dev,
  			  struct device_attribute *attr, char *buf)
  {

  	struct dock_station *dock_station = dev->platform_data;

  	return snprintf(buf, PAGE_SIZE, "%d
  ", dock_station->flags);
  
  }

  static DEVICE_ATTR(flags, S_IRUGO, show_flags, NULL);

  
  /*

   * write_undock - write method for "undock" file in sysfs
   */
  static ssize_t write_undock(struct device *dev, struct device_attribute *attr,
  			   const char *buf, size_t count)
  {
  	int ret;

  	struct dock_station *dock_station = dev->platform_data;

  
  	if (!count)
  		return -EINVAL;

  	acpi_scan_lock_acquire();

  	begin_undock(dock_station);

  	ret = handle_eject_request(dock_station, ACPI_NOTIFY_EJECT_REQUEST);

  	acpi_scan_lock_release();

  	return ret ? ret: count;
  }

  static DEVICE_ATTR(undock, S_IWUSR, NULL, write_undock);

  /*
   * show_dock_uid - read method for "uid" file in sysfs
   */
  static ssize_t show_dock_uid(struct device *dev,
  			     struct device_attribute *attr, char *buf)
  {

  	unsigned long long lbuf;

  	struct dock_station *dock_station = dev->platform_data;

  	acpi_status status = acpi_evaluate_integer(dock_station->handle,
  					"_UID", NULL, &lbuf);
  	if (ACPI_FAILURE(status))

  	    return 0;

  	return snprintf(buf, PAGE_SIZE, "%llx
  ", lbuf);

  }

  static DEVICE_ATTR(uid, S_IRUGO, show_dock_uid, NULL);

  static ssize_t show_dock_type(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {

  	struct dock_station *dock_station = dev->platform_data;

  	char *type;
  
  	if (dock_station->flags & DOCK_IS_DOCK)
  		type = "dock_station";
  	else if (dock_station->flags & DOCK_IS_ATA)
  		type = "ata_bay";
  	else if (dock_station->flags & DOCK_IS_BAT)
  		type = "battery_bay";
  	else
  		type = "unknown";
  
  	return snprintf(buf, PAGE_SIZE, "%s
  ", type);
  }
  static DEVICE_ATTR(type, S_IRUGO, show_dock_type, NULL);

  static struct attribute *dock_attributes[] = {
  	&dev_attr_docked.attr,
  	&dev_attr_flags.attr,
  	&dev_attr_undock.attr,
  	&dev_attr_uid.attr,
  	&dev_attr_type.attr,
  	NULL
  };

  static const struct attribute_group dock_attribute_group = {

  	.attrs = dock_attributes
  };

  /**

   * acpi_dock_add - Add a new dock station
   * @adev: Dock station ACPI device object.

   *

   * allocated and initialize a new dock station device.

   */

  void acpi_dock_add(struct acpi_device *adev)

  {

  	struct dock_station *dock_station, ds = { NULL, };

  	struct platform_device_info pdevinfo;

  	acpi_handle handle = adev->handle;

  	struct platform_device *dd;

  	int ret;

  	memset(&pdevinfo, 0, sizeof(pdevinfo));
  	pdevinfo.name = "dock";
  	pdevinfo.id = dock_station_count;

  	pdevinfo.fwnode = acpi_fwnode_handle(adev);

  	pdevinfo.data = &ds;
  	pdevinfo.size_data = sizeof(ds);
  	dd = platform_device_register_full(&pdevinfo);

  	if (IS_ERR(dd))

  		return;

  
  	dock_station = dd->dev.platform_data;

  	dock_station->handle = handle;

  	dock_station->dock_device = dd;

  	dock_station->last_dock_time = jiffies - HZ;

  	INIT_LIST_HEAD(&dock_station->sibling);

  	INIT_LIST_HEAD(&dock_station->dependent_devices);

  	/* we want the dock device to send uevents */

  	dev_set_uevent_suppress(&dd->dev, 0);

  	if (acpi_dock_match(handle))

  		dock_station->flags |= DOCK_IS_DOCK;

  	if (acpi_ata_match(handle))

  		dock_station->flags |= DOCK_IS_ATA;

  	if (acpi_device_is_battery(adev))

  		dock_station->flags |= DOCK_IS_BAT;

  	ret = sysfs_create_group(&dd->dev.kobj, &dock_attribute_group);

  	if (ret)

  		goto err_unregister;

  	/* add the dock station as a device dependent on itself */

  	ret = add_dock_dependent_device(dock_station, adev);

  	if (ret)

  		goto err_rmgroup;

  	dock_station_count++;

  	list_add(&dock_station->sibling, &dock_stations);

  	adev->flags.is_dock_station = true;
  	dev_info(&adev->dev, "ACPI dock station (docks/bays count: %d)
  ",
  		 dock_station_count);
  	return;

  err_rmgroup:

  	sysfs_remove_group(&dd->dev.kobj, &dock_attribute_group);

  err_unregister:

  	platform_device_unregister(dd);

  	acpi_handle_err(handle, "%s encountered error %d
  ", __func__, ret);

  }