/*
* dock.c - ACPI dock station driver
*
* Copyright (C) 2006 Kristen Carlson Accardi <kristen.c.accardi@intel.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/notifier.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#define ACPI_DOCK_DRIVER_NAME "ACPI Dock Station Driver"
ACPI_MODULE_NAME("dock")
MODULE_AUTHOR("Kristen Carlson Accardi");
MODULE_DESCRIPTION(ACPI_DOCK_DRIVER_NAME);
MODULE_LICENSE("GPL");
static struct atomic_notifier_head dock_notifier_list;
struct dock_station {
acpi_handle handle;
unsigned long last_dock_time;
u32 flags;
spinlock_t dd_lock;
spinlock_t hp_lock;
struct list_head dependent_devices;
struct list_head hotplug_devices;
};
struct dock_dependent_device {
struct list_head list;
struct list_head hotplug_list;
acpi_handle handle;
acpi_notify_handler handler;
void *context;
};
#define DOCK_DOCKING 0x00000001
#define DOCK_EVENT KOBJ_DOCK
#define UNDOCK_EVENT KOBJ_UNDOCK
static struct dock_station *dock_station;
/*****************************************************************************
* Dock Dependent device functions *
*****************************************************************************/
/**
* alloc_dock_dependent_device - allocate and init a dependent device
* @handle: the acpi_handle of the dependent device
*
* Allocate memory for a dependent device structure for a device referenced
* by the acpi handle
*/
static struct dock_dependent_device *
alloc_dock_dependent_device(acpi_handle handle)
{
struct dock_dependent_device *dd;
dd = kzalloc(sizeof(*dd), GFP_KERNEL);
if (dd) {
dd->handle = handle;
INIT_LIST_HEAD(&dd->list);
INIT_LIST_HEAD(&dd->hotplug_list);
}
return dd;
}
/**
* add_dock_dependent_device - associate a device with the dock station
* @ds: The dock station
* @dd: The dependent device
*
* Add the dependent device to the dock's dependent device list.
*/
static void
add_dock_dependent_device(struct dock_station *ds,
struct dock_dependent_device *dd)
{
spin_lock(&ds->dd_lock);
list_add_tail(&dd->list, &ds->dependent_devices);
spin_unlock(&ds->dd_lock);
}
/**
* dock_add_hotplug_device - associate a hotplug handler with the dock station
* @ds: The dock station
* @dd: The dependent device struct
*
* Add the dependent device to the dock's hotplug device list
*/
static void
dock_add_hotplug_device(struct dock_station *ds,
struct dock_dependent_device *dd)
{
spin_lock(&ds->hp_lock);
list_add_tail(&dd->hotplug_list, &ds->hotplug_devices);
spin_unlock(&ds->hp_lock);
}
/**
* dock_del_hotplug_device - remove a hotplug handler from the dock station
* @ds: The dock station
* @dd: the dependent device struct
*
* Delete the dependent device from the dock's hotplug device list
*/
static void
dock_del_hotplug_device(struct dock_station *ds,
struct dock_dependent_device *dd)
{
spin_lock(&ds->hp_lock);
list_del(&dd->hotplug_list);
spin_unlock(&ds->hp_lock);
}
/**
* find_dock_dependent_device - get a device dependent on this dock
* @ds: the dock station
* @handle: the acpi_handle of the device we want
*
* 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, acpi_handle handle)
{
struct dock_dependent_device *dd;
spin_lock(&ds->dd_lock);
list_for_each_entry(dd, &ds->dependent_devices, list) {
if (handle == dd->handle) {
spin_unlock(&ds->dd_lock);
return dd;
}
}
spin_unlock(&ds->dd_lock);
return NULL;
}
/*****************************************************************************
* Dock functions *
*****************************************************************************/
/**
* is_dock - see if a device is a dock station
* @handle: acpi handle of the device
*
* If an acpi object has a _DCK method, then it is by definition a dock
* station, so return true.
*/
static int is_dock(acpi_handle handle)
{
acpi_status status;
acpi_handle tmp;
status = acpi_get_handle(handle, "_DCK", &tmp);
if (ACPI_FAILURE(status))
return 0;
return 1;
}
/**
* is_dock_device - see if a device is on a dock station
* @handle: acpi handle of the device
*
* 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(acpi_handle handle)
{
if (!dock_station)
return 0;
if (is_dock(handle) || find_dock_dependent_device(dock_station, handle))
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 sta;
acpi_status status;
if (ds) {
status = acpi_evaluate_integer(ds->handle, "_STA", NULL, &sta);
if (ACPI_SUCCESS(status) && sta)
return 1;
}
return 0;
}
/**
* dock_create_acpi_device - add new devices to acpi
* @handle - handle of the device to add
*
* This function will create a new acpi_device for the given
* handle if one does not exist already. This should cause
* acpi to scan for drivers for the given devices, and call
* matching driver's add routine.
*
* Returns a pointer to the acpi_device corresponding to the handle.
*/
static struct acpi_device * dock_create_acpi_device(acpi_handle handle)
{
struct acpi_device *device = NULL;
struct acpi_device *parent_device;
acpi_handle parent;
int ret;
if (acpi_bus_get_device(handle, &device)) {
/*
* no device created for this object,
* so we should create one.
*/
acpi_get_parent(handle, &parent);
if (acpi_bus_get_device(parent, &parent_device))
parent_device = NULL;
ret = acpi_bus_add(&device, parent_device, handle,
ACPI_BUS_TYPE_DEVICE);
if (ret) {
pr_debug("error adding bus, %x\n",
-ret);
return NULL;
}
}
return device;
}
/**
* dock_remove_acpi_device - remove the acpi_device struct from acpi
* @handle - the handle of the device to remove
*
* Tell acpi to remove the acpi_device. This should cause any loaded
* driver to have it's remove routine called.
*/
static void dock_remove_acpi_device(acpi_handle handle)
{
struct acpi_device *device;
int ret;
if (!acpi_bus_get_device(handle, &device)) {
ret = acpi_bus_trim(device, 1);
if (ret)
pr_debug("error removing bus, %x\n", -ret);
}
}
/**
* hotplug_dock_devices - insert or remove devices on the dock station
* @ds: the dock station
* @event: either bus check or eject 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;
spin_lock(&ds->hp_lock);
/*
* First call driver specific hotplug functions
*/
list_for_each_entry(dd, &ds->hotplug_devices, hotplug_list) {
if (dd->handler)
dd->handler(dd->handle, event, dd->context);
}
/*
* Now make sure that an acpi_device is created for each
* dependent device, or removed if this is an eject request.
* This will cause acpi_drivers to be stopped/started if they
* exist
*/
list_for_each_entry(dd, &ds->dependent_devices, list) {
if (event == ACPI_NOTIFY_EJECT_REQUEST)
dock_remove_acpi_device(dd->handle);
else
dock_create_acpi_device(dd->handle);
}
spin_unlock(&ds->hp_lock);
}
static void dock_event(struct dock_station *ds, u32 event, int num)
{
struct acpi_device *device;
device = dock_create_acpi_device(ds->handle);
if (device)
kobject_uevent(&device->kobj, num);
}
/**
* eject_dock - respond to a dock eject request
* @ds: the dock station
*
* This is called after _DCK is called, to execute the dock station's
* _EJ0 method.
*/
static void eject_dock(struct dock_station *ds)
{
struct acpi_object_list arg_list;
union acpi_object arg;
acpi_status status;
acpi_handle tmp;
/* all dock devices should have _EJ0, but check anyway */
status = acpi_get_handle(ds->handle, "_EJ0", &tmp);
if (ACPI_FAILURE(status)) {
pr_debug("No _EJ0 support for dock device\n");
return;
}
arg_list.count = 1;
arg_list.pointer = &arg;
arg.type = ACPI_TYPE_INTEGER;
arg.integer.value = 1;
if (ACPI_FAILURE(acpi_evaluate_object(ds->handle, "_EJ0",
&arg_list, NULL)))
pr_debug("Failed to evaluate _EJ0!\n");
}
/**
* 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;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
struct acpi_buffer name_buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *obj;
acpi_get_name(ds->handle, ACPI_FULL_PATHNAME, &name_buffer);
obj = name_buffer.pointer;
printk(KERN_INFO PREFIX "%s\n", 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_object(ds->handle, "_DCK", &arg_list, &buffer);
if (ACPI_FAILURE(status))
pr_debug("%s: failed to execute _DCK\n", obj->string.pointer);
kfree(buffer.pointer);
kfree(name_buffer.pointer);
}
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;
}
/**
* 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;
}
/**
* register_dock_notifier - add yourself to the dock notifier list
* @nb: the callers notifier block
*
* If a driver wishes to be notified about dock events, they can
* use this function to put a notifier block on the dock notifier list.
* this notifier call chain will be called after a dock event, but
* before hotplugging any new devices.
*/
int register_dock_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&dock_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(register_dock_notifier);
/**
* unregister_dock_notifier - remove yourself from the dock notifier list
* @nb: the callers notifier block
*/
void unregister_dock_notifier(struct notifier_block *nb)
{
atomic_notifier_chain_unregister(&dock_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(unregister_dock_notifier);
/**
* register_hotplug_dock_device - register a hotplug function
* @handle: the handle of the device
* @handler: the acpi_notifier_handler to call after docking
* @context: device specific data
*
* If a driver would like to perform a hotplug operation after a dock
* event, they can register an acpi_notifiy_handler to be called by
* the dock driver after _DCK is executed.
*/
int
register_hotplug_dock_device(acpi_handle handle, acpi_notify_handler handler,
void *context)
{
struct dock_dependent_device *dd;
if (!dock_station)
return -ENODEV;
/*
* make sure this handle is for a device dependent on the dock,
* this would include the dock station itself
*/
dd = find_dock_dependent_device(dock_station, handle);
if (dd) {
dd->handler = handler;
dd->context = context;
dock_add_hotplug_device(dock_station, dd);
return 0;
}
return -EINVAL;
}
EXPORT_SYMBOL_GPL(register_hotplug_dock_device);
/**
* unregister_hotplug_dock_device - remove yourself from the hotplug list
* @handle: the acpi handle of the device
*/
void unregister_hotplug_dock_device(acpi_handle handle)
{
struct dock_dependent_device *dd;
if (!dock_station)
return;
dd = find_dock_dependent_device(dock_station, handle);
if (dd)
dock_del_hotplug_device(dock_station, dd);
}
EXPORT_SYMBOL_GPL(unregister_hotplug_dock_device);
/**
* dock_notify - act upon an acpi dock notification
* @handle: the dock station handle
* @event: the acpi event
* @data: our driver data struct
*
* 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. For undock
* check to make sure the dock device is still present, then undock
* and hotremove all the devices that may need removing.
*/
static void dock_notify(acpi_handle handle, u32 event, void *data)
{
struct dock_station *ds = (struct dock_station *)data;
switch (event) {
case ACPI_NOTIFY_BUS_CHECK:
if (!dock_in_progress(ds) && dock_present(ds)) {
begin_dock(ds);
dock(ds);
if (!dock_present(ds)) {
printk(KERN_ERR PREFIX "Unable to dock!\n");
break;
}
atomic_notifier_call_chain(&dock_notifier_list,
event, NULL);
hotplug_dock_devices(ds, event);
complete_dock(ds);
dock_event(ds, event, DOCK_EVENT);
}
break;
case ACPI_NOTIFY_DEVICE_CHECK:
/*
* 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. This notify routine will only be called
* for objects defining _DCK, so we will fall through to eject
* request here. However, we will pass an eject request through
* to the driver who wish to hotplug.
*/
case ACPI_NOTIFY_EJECT_REQUEST:
if (!dock_in_progress(ds) && dock_present(ds)) {
/*
* here we need to generate the undock
* event prior to actually doing the undock
* so that the device struct still exists.
*/
dock_event(ds, event, UNDOCK_EVENT);
hotplug_dock_devices(ds, ACPI_NOTIFY_EJECT_REQUEST);
undock(ds);
eject_dock(ds);
if (dock_present(ds))
printk(KERN_ERR PREFIX "Unable to undock!\n");
}
break;
default:
printk(KERN_ERR PREFIX "Unknown dock event %d\n", event);
}
}
/**
* find_dock_devices - find devices on the dock station
* @handle: the handle of the device we are examining
* @lvl: unused
* @context: the dock station private data
* @rv: unused
*
* This function is called by acpi_walk_namespace. It will
* check to see if an object has an _EJD method. If it does, then it
* will see if it is dependent on the dock station.
*/
static acpi_status
find_dock_devices(acpi_handle handle, u32 lvl, void *context, void **rv)
{
acpi_status status;
acpi_handle tmp;
struct dock_station *ds = (struct dock_station *)context;
struct dock_dependent_device *dd;
status = acpi_bus_get_ejd(handle, &tmp);
if (ACPI_FAILURE(status))
return AE_OK;
if (tmp == ds->handle) {
dd = alloc_dock_dependent_device(handle);
if (dd)
add_dock_dependent_device(ds, dd);
}
return AE_OK;
}
/**
* dock_add - add a new dock station
* @handle: the dock station handle
*
* allocated and initialize a new dock station device. Find all devices
* that are on the dock station, and register for dock event notifications.
*/
static int dock_add(acpi_handle handle)
{
int ret;
acpi_status status;
struct dock_dependent_device *dd;
/* allocate & initialize the dock_station private data */
dock_station = kzalloc(sizeof(*dock_station), GFP_KERNEL);
if (!dock_station)
return -ENOMEM;
dock_station->handle = handle;
dock_station->last_dock_time = jiffies - HZ;
INIT_LIST_HEAD(&dock_station->dependent_devices);
INIT_LIST_HEAD(&dock_station->hotplug_devices);
spin_lock_init(&dock_station->dd_lock);
spin_lock_init(&dock_station->hp_lock);
/* Find dependent devices */
acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX, find_dock_devices, dock_station,
NULL);
/* add the dock station as a device dependent on itself */
dd = alloc_dock_dependent_device(handle);
if (!dd) {
kfree(dock_station);
return -ENOMEM;
}
add_dock_dependent_device(dock_station, dd);
/* register for dock events */
status = acpi_install_notify_handler(dock_station->handle,
ACPI_SYSTEM_NOTIFY,
dock_notify, dock_station);
if (ACPI_FAILURE(status)) {
printk(KERN_ERR PREFIX "Error installing notify handler\n");
ret = -ENODEV;
goto dock_add_err;
}
printk(KERN_INFO PREFIX "%s \n", ACPI_DOCK_DRIVER_NAME);
return 0;
dock_add_err:
kfree(dock_station);
kfree(dd);
return ret;
}
/**
* dock_remove - free up resources related to the dock station
*/
static int dock_remove(void)
{
struct dock_dependent_device *dd, *tmp;
acpi_status status;
if (!dock_station)
return 0;
/* remove dependent devices */
list_for_each_entry_safe(dd, tmp, &dock_station->dependent_devices,
list)
kfree(dd);
/* remove dock notify handler */
status = acpi_remove_notify_handler(dock_station->handle,
ACPI_SYSTEM_NOTIFY,
dock_notify);
if (ACPI_FAILURE(status))
printk(KERN_ERR "Error removing notify handler\n");
/* free dock station memory */
kfree(dock_station);
return 0;
}
/**
* find_dock - look for a dock station
* @handle: acpi handle of a device
* @lvl: unused
* @context: counter of dock stations found
* @rv: unused
*
* This is called by acpi_walk_namespace to look for dock stations.
*/
static acpi_status
find_dock(acpi_handle handle, u32 lvl, void *context, void **rv)
{
int *count = (int *)context;
acpi_status status = AE_OK;
if (is_dock(handle)) {
if (dock_add(handle) >= 0) {
(*count)++;
status = AE_CTRL_TERMINATE;
}
}
return status;
}
static int __init dock_init(void)
{
int num = 0;
dock_station = NULL;
/* look for a dock station */
acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX, find_dock, &num, NULL);
if (!num)
return -ENODEV;
return 0;
}
static void __exit dock_exit(void)
{
dock_remove();
}
postcore_initcall(dock_init);
module_exit(dock_exit);
