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kernel-ark/drivers/acpi/dock.c
Rafael J. Wysocki 21a31013f7 ACPI / dock / PCI: Synchronous handling of dock events for PCI devices 
The interactions between the ACPI dock driver and the ACPI-based PCI
hotplug (acpiphp) are currently problematic because of ordering
issues during hot-remove operations.

First of all, the current ACPI glue code expects that physical
devices will always be deleted before deleting the companion ACPI
device objects.  Otherwise, acpi_unbind_one() will fail with a
warning message printed to the kernel log, for example:

[  185.026073] usb usb5: Oops, 'acpi_handle' corrupt
[  185.035150] pci 0000:1b:00.0: Oops, 'acpi_handle' corrupt
[  185.035515] pci 0000:18:02.0: Oops, 'acpi_handle' corrupt
[  180.013656]  port1: Oops, 'acpi_handle' corrupt

This means, in particular, that struct pci_dev objects have to
be deleted before the struct acpi_device objects they are "glued"
with.

Now, the following happens the during the undocking of an ACPI-based
dock station:
 1) hotplug_dock_devices() invokes registered hotplug callbacks to
    destroy physical devices associated with the ACPI device objects
    depending on the dock station.  It calls dd->ops->handler() for
    each of those device objects.
 2) For PCI devices dd->ops->handler() points to
    handle_hotplug_event_func() that queues up a separate work item
    to execute _handle_hotplug_event_func() for the given device and
    returns immediately.  That work item will be executed later.
 3) hotplug_dock_devices() calls dock_remove_acpi_device() for each
    device depending on the dock station.  This runs acpi_bus_trim()
    for each of them, which causes the underlying ACPI device object
    to be destroyed, but the work items queued up by
    handle_hotplug_event_func() haven't been started yet.
 4) _handle_hotplug_event_func() queued up in step 2) are executed
    and cause the above failure to happen, because the PCI devices
    they handle do not have the companion ACPI device objects any
    more (those objects have been deleted in step 3).

The possible breakage doesn't end here, though, because
hotplug_dock_devices() may return before at least some of the
_handle_hotplug_event_func() work items spawned by it have a
chance to complete and then undock() will cause _DCK to be
evaluated and that will cause the devices handled by the
_handle_hotplug_event_func() to go away possibly while they are
being accessed.

This means that dd->ops->handler() for PCI devices should not point
to handle_hotplug_event_func().  Instead, it should point to a
function that will do the work of _handle_hotplug_event_func()
synchronously.  For this reason, introduce such a function,
hotplug_event_func(), and modity acpiphp_dock_ops to point to
it as the handler.

Unfortunately, however, this is not sufficient, because if the dock
code were not changed further, hotplug_event_func() would now
deadlock with hotplug_dock_devices() that called it, since it would
run unregister_hotplug_dock_device() which in turn would attempt to
acquire the dock station's hp_lock mutex already acquired by
hotplug_dock_devices().

To resolve that deadlock use the observation that
unregister_hotplug_dock_device() won't need to acquire hp_lock
if PCI bridges the devices on the dock station depend on are
prevented from being removed prematurely while the first loop in
hotplug_dock_devices() is in progress.

To make that possible, introduce a mechanism by which the callers of
register_hotplug_dock_device() can provide "init" and "release"
routines that will be executed, respectively, during the addition
and removal of the physical device object associated with the
given ACPI device handle.  Make acpiphp use two new functions,
acpiphp_dock_init() and acpiphp_dock_release(), that call
get_bridge() and put_bridge(), respectively, on the acpiphp bridge
holding the given device, for this purpose.

In addition to that, remove the dock station's list of
"hotplug devices" and make the dock code always walk the whole list
of "dependent devices" instead in such a way that the loops in
hotplug_dock_devices() and dock_event() (replacing the loops over
"hotplug devices") will take references to the list entries that
register_hotplug_dock_device() has been called for.  That prevents
the "release" routines associated with those entries from being
called while the given entry is being processed and for PCI
devices this means that their bridges won't be removed (by a
concurrent thread) while hotplug_event_func() handling them is
being executed.

This change is based on two earlier patches from Jiang Liu.

References: https://bugzilla.kernel.org/show_bug.cgi?id=59501
Reported-and-tested-by: Alexander E. Patrakov <patrakov@gmail.com>
Tracked-down-by: Jiang Liu <jiang.liu@huawei.com>
Tested-by: Illya Klymov <xanf@xanf.me>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: 3.9+ <stable@vger.kernel.org>
2013-06-24 11:22:53 +02:00

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/*
* 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/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 <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#define PREFIX "ACPI: "
#define ACPI_DOCK_DRIVER_DESCRIPTION "ACPI Dock Station Driver"
ACPI_MODULE_NAME("dock");
MODULE_AUTHOR("Kristen Carlson Accardi");
MODULE_DESCRIPTION(ACPI_DOCK_DRIVER_DESCRIPTION);
MODULE_LICENSE("GPL");
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");
static struct atomic_notifier_head dock_notifier_list;
static const struct acpi_device_id dock_device_ids[] = {
{"LNXDOCK", 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, dock_device_ids);
struct dock_station {
acpi_handle handle;
unsigned long last_dock_time;
u32 flags;
spinlock_t dd_lock;
struct mutex hp_lock;
struct list_head dependent_devices;
struct list_head sibling;
struct platform_device *dock_device;
};
static LIST_HEAD(dock_stations);
static int dock_station_count;
static DEFINE_MUTEX(hotplug_lock);
struct dock_dependent_device {
struct list_head list;
acpi_handle handle;
const struct acpi_dock_ops *hp_ops;
void *hp_context;
unsigned int hp_refcount;
void (*hp_release)(void *);
};
#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
/*****************************************************************************
* Dock Dependent device functions *
*****************************************************************************/
/**
* add_dock_dependent_device - associate a device with the dock station
* @ds: The dock station
* @handle: handle of the dependent device
*
* Add the dependent device to the dock's dependent device list.
*/
static int
add_dock_dependent_device(struct dock_station *ds, acpi_handle handle)
{
struct dock_dependent_device *dd;
dd = kzalloc(sizeof(*dd), GFP_KERNEL);
if (!dd)
return -ENOMEM;
dd->handle = handle;
INIT_LIST_HEAD(&dd->list);
spin_lock(&ds->dd_lock);
list_add_tail(&dd->list, &ds->dependent_devices);
spin_unlock(&ds->dd_lock);
return 0;
}
/**
* dock_init_hotplug - Initialize a hotplug device on a docking station.
* @dd: Dock-dependent device.
* @ops: Dock operations to attach to the dependent device.
* @context: Data to pass to the @ops callbacks and @release.
* @init: Optional initialization routine to run after setting up context.
* @release: Optional release routine to run on removal.
*/
static int dock_init_hotplug(struct dock_dependent_device *dd,
const struct acpi_dock_ops *ops, void *context,
void (*init)(void *), void (*release)(void *))
{
int ret = 0;
mutex_lock(&hotplug_lock);
if (dd->hp_context) {
ret = -EEXIST;
} else {
dd->hp_refcount = 1;
dd->hp_ops = ops;
dd->hp_context = context;
dd->hp_release = release;
}
if (!WARN_ON(ret) && init)
init(context);
mutex_unlock(&hotplug_lock);
return ret;
}
/**
* dock_release_hotplug - Decrement hotplug reference counter of dock device.
* @dd: Dock-dependent device.
*
* Decrement the reference counter of @dd and if 0, detach its hotplug
* operations from it, reset its context pointer and run the optional release
* routine if present.
*/
static void dock_release_hotplug(struct dock_dependent_device *dd)
{
void (*release)(void *) = NULL;
void *context = NULL;
mutex_lock(&hotplug_lock);
if (dd->hp_context && !--dd->hp_refcount) {
dd->hp_ops = NULL;
context = dd->hp_context;
dd->hp_context = NULL;
release = dd->hp_release;
dd->hp_release = NULL;
}
if (release && context)
release(context);
mutex_unlock(&hotplug_lock);
}
static void dock_hotplug_event(struct dock_dependent_device *dd, u32 event,
bool uevent)
{
acpi_notify_handler cb = NULL;
bool run = false;
mutex_lock(&hotplug_lock);
if (dd->hp_context) {
run = true;
dd->hp_refcount++;
if (dd->hp_ops)
cb = uevent ? dd->hp_ops->uevent : dd->hp_ops->handler;
}
mutex_unlock(&hotplug_lock);
if (!run)
return;
if (cb)
cb(dd->handle, event, dd->hp_context);
dock_release_hotplug(dd);
}
/**
* 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;
}
static int is_ejectable(acpi_handle handle)
{
acpi_status status;
acpi_handle tmp;
status = acpi_get_handle(handle, "_EJ0", &tmp);
if (ACPI_FAILURE(status))
return 0;
return 1;
}
static int is_ata(acpi_handle handle)
{
acpi_handle tmp;
if ((ACPI_SUCCESS(acpi_get_handle(handle, "_GTF", &tmp))) ||
(ACPI_SUCCESS(acpi_get_handle(handle, "_GTM", &tmp))) ||
(ACPI_SUCCESS(acpi_get_handle(handle, "_STM", &tmp))) ||
(ACPI_SUCCESS(acpi_get_handle(handle, "_SDD", &tmp))))
return 1;
return 0;
}
static int is_battery(acpi_handle handle)
{
struct acpi_device_info *info;
int ret = 1;
if (!ACPI_SUCCESS(acpi_get_object_info(handle, &info)))
return 0;
if (!(info->valid & ACPI_VALID_HID))
ret = 0;
else
ret = !strcmp("PNP0C0A", info->hardware_id.string);
kfree(info);
return ret;
}
static int is_ejectable_bay(acpi_handle handle)
{
acpi_handle phandle;
if (!is_ejectable(handle))
return 0;
if (is_battery(handle) || is_ata(handle))
return 1;
if (!acpi_get_parent(handle, &phandle) && is_ata(phandle))
return 1;
return 0;
}
/**
* 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)
{
struct dock_station *dock_station;
if (!dock_station_count)
return 0;
if (is_dock(handle))
return 1;
list_for_each_entry(dock_station, &dock_stations, sibling)
if (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 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;
int ret;
if (acpi_bus_get_device(handle, &device)) {
/*
* no device created for this object,
* so we should create one.
*/
ret = acpi_bus_scan(handle);
if (ret)
pr_debug("error adding bus, %x\n", -ret);
acpi_bus_get_device(handle, &device);
}
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;
if (!acpi_bus_get_device(handle, &device))
acpi_bus_trim(device);
}
/**
* 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;
mutex_lock(&ds->hp_lock);
/*
* First call driver specific hotplug functions
*/
list_for_each_entry(dd, &ds->dependent_devices, list)
dock_hotplug_event(dd, event, false);
/*
* 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);
}
mutex_unlock(&ds->hp_lock);
}
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, true);
if (num != DOCK_EVENT)
kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
}
/**
* 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;
status = acpi_evaluate_object(ds->handle, "_EJ0", &arg_list, NULL);
if (ACPI_FAILURE(status))
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 };
acpi_handle_info(ds->handle, "%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) && status != AE_NOT_FOUND)
acpi_handle_err(ds->handle, "Failed to execute _DCK (0x%x)\n",
status);
kfree(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;
}
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);
}
static void dock_lock(struct dock_station *ds, int lock)
{
struct acpi_object_list arg_list;
union acpi_object arg;
acpi_status status;
arg_list.count = 1;
arg_list.pointer = &arg;
arg.type = ACPI_TYPE_INTEGER;
arg.integer.value = !!lock;
status = acpi_evaluate_object(ds->handle, "_LCK", &arg_list, NULL);
if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
if (lock)
acpi_handle_warn(ds->handle,
"Locking device failed (0x%x)\n", status);
else
acpi_handle_warn(ds->handle,
"Unlocking device failed (0x%x)\n", status);
}
}
/**
* 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)
{
if (!dock_station_count)
return -ENODEV;
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)
{
if (!dock_station_count)
return;
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
* @ops: handlers to call after docking
* @context: device specific data
* @init: Optional initialization routine to run after registration
* @release: Optional release routine to run on unregistration
*
* 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,
const struct acpi_dock_ops *ops, void *context,
void (*init)(void *), void (*release)(void *))
{
struct dock_dependent_device *dd;
struct dock_station *dock_station;
int ret = -EINVAL;
if (WARN_ON(!context))
return -EINVAL;
if (!dock_station_count)
return -ENODEV;
/*
* make sure this handle is for a device dependent on the dock,
* this would include the dock station itself
*/
list_for_each_entry(dock_station, &dock_stations, sibling) {
/*
* An ATA bay can be in a dock and itself can be ejected
* separately, so there are two 'dock stations' which need the
* ops
*/
dd = find_dock_dependent_device(dock_station, handle);
if (dd && !dock_init_hotplug(dd, ops, context, init, release))
ret = 0;
}
return ret;
}
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;
struct dock_station *dock_station;
if (!dock_station_count)
return;
list_for_each_entry(dock_station, &dock_stations, sibling) {
dd = find_dock_dependent_device(dock_station, handle);
if (dd)
dock_release_hotplug(dd);
}
}
EXPORT_SYMBOL_GPL(unregister_hotplug_dock_device);
/**
* 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);
hotplug_dock_devices(ds, ACPI_NOTIFY_EJECT_REQUEST);
undock(ds);
dock_lock(ds, 0);
eject_dock(ds);
if (dock_present(ds)) {
acpi_handle_err(ds->handle, "Unable to undock!\n");
return -EBUSY;
}
complete_undock(ds);
return 0;
}
/**
* 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.
*/
static void dock_notify(acpi_handle handle, u32 event, void *data)
{
struct dock_station *ds = data;
struct acpi_device *tmp;
int surprise_removal = 0;
/*
* 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_bus_get_device(ds->handle,
&tmp)) {
begin_dock(ds);
dock(ds);
if (!dock_present(ds)) {
acpi_handle_err(handle, "Unable to dock!\n");
complete_dock(ds);
break;
}
atomic_notifier_call_chain(&dock_notifier_list,
event, NULL);
hotplug_dock_devices(ds, event);
complete_dock(ds);
dock_event(ds, event, DOCK_EVENT);
dock_lock(ds, 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 */
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;
default:
acpi_handle_err(handle, "Unknown dock event %d\n", event);
}
}
struct dock_data {
acpi_handle handle;
unsigned long event;
struct dock_station *ds;
};
static void acpi_dock_deferred_cb(void *context)
{
struct dock_data *data = context;
acpi_scan_lock_acquire();
dock_notify(data->handle, data->event, data->ds);
acpi_scan_lock_release();
kfree(data);
}
static int acpi_dock_notifier_call(struct notifier_block *this,
unsigned long event, void *data)
{
struct dock_station *dock_station;
acpi_handle handle = data;
if (event != ACPI_NOTIFY_BUS_CHECK && event != ACPI_NOTIFY_DEVICE_CHECK
&& event != ACPI_NOTIFY_EJECT_REQUEST)
return 0;
acpi_scan_lock_acquire();
list_for_each_entry(dock_station, &dock_stations, sibling) {
if (dock_station->handle == handle) {
struct dock_data *dd;
acpi_status status;
dd = kmalloc(sizeof(*dd), GFP_KERNEL);
if (!dd)
break;
dd->handle = handle;
dd->event = event;
dd->ds = dock_station;
status = acpi_os_hotplug_execute(acpi_dock_deferred_cb,
dd);
if (ACPI_FAILURE(status))
kfree(dd);
break;
}
}
acpi_scan_lock_release();
return 0;
}
static struct notifier_block dock_acpi_notifier = {
.notifier_call = acpi_dock_notifier_call,
};
/**
* 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, parent;
struct dock_station *ds = context;
status = acpi_bus_get_ejd(handle, &tmp);
if (ACPI_FAILURE(status)) {
/* try the parent device as well */
status = acpi_get_parent(handle, &parent);
if (ACPI_FAILURE(status))
goto fdd_out;
/* see if parent is dependent on dock */
status = acpi_bus_get_ejd(parent, &tmp);
if (ACPI_FAILURE(status))
goto fdd_out;
}
if (tmp == ds->handle)
add_dock_dependent_device(ds, handle);
fdd_out:
return AE_OK;
}
/*
* show_docked - read method for "docked" file in sysfs
*/
static ssize_t show_docked(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct acpi_device *tmp;
struct dock_station *dock_station = dev->platform_data;
if (!acpi_bus_get_device(dock_station->handle, &tmp))
return snprintf(buf, PAGE_SIZE, "1\n");
return snprintf(buf, PAGE_SIZE, "0\n");
}
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\n", 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\n", 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\n", 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 struct attribute_group dock_attribute_group = {
.attrs = dock_attributes
};
/**
* 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 __init dock_add(acpi_handle handle)
{
int ret, id;
struct dock_station ds, *dock_station;
struct platform_device *dd;
id = dock_station_count;
memset(&ds, 0, sizeof(ds));
dd = platform_device_register_data(NULL, "dock", id, &ds, sizeof(ds));
if (IS_ERR(dd))
return PTR_ERR(dd);
dock_station = dd->dev.platform_data;
dock_station->handle = handle;
dock_station->dock_device = dd;
dock_station->last_dock_time = jiffies - HZ;
mutex_init(&dock_station->hp_lock);
spin_lock_init(&dock_station->dd_lock);
INIT_LIST_HEAD(&dock_station->sibling);
ATOMIC_INIT_NOTIFIER_HEAD(&dock_notifier_list);
INIT_LIST_HEAD(&dock_station->dependent_devices);
/* we want the dock device to send uevents */
dev_set_uevent_suppress(&dd->dev, 0);
if (is_dock(handle))
dock_station->flags |= DOCK_IS_DOCK;
if (is_ata(handle))
dock_station->flags |= DOCK_IS_ATA;
if (is_battery(handle))
dock_station->flags |= DOCK_IS_BAT;
ret = sysfs_create_group(&dd->dev.kobj, &dock_attribute_group);
if (ret)
goto err_unregister;
/* Find dependent devices */
acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX, find_dock_devices, NULL,
dock_station, NULL);
/* add the dock station as a device dependent on itself */
ret = add_dock_dependent_device(dock_station, handle);
if (ret)
goto err_rmgroup;
dock_station_count++;
list_add(&dock_station->sibling, &dock_stations);
return 0;
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\n", __func__, ret);
return ret;
}
/**
* find_dock_and_bay - look for dock stations and bays
* @handle: acpi handle of a device
* @lvl: unused
* @context: unused
* @rv: unused
*
* This is called by acpi_walk_namespace to look for dock stations and bays.
*/
static __init acpi_status
find_dock_and_bay(acpi_handle handle, u32 lvl, void *context, void **rv)
{
if (is_dock(handle) || is_ejectable_bay(handle))
dock_add(handle);
return AE_OK;
}
int __init acpi_dock_init(void)
{
if (acpi_disabled)
return 0;
/* look for dock stations and bays */
acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX, find_dock_and_bay, NULL, NULL, NULL);
if (!dock_station_count) {
pr_info(PREFIX "No dock devices found.\n");
return 0;
}
register_acpi_bus_notifier(&dock_acpi_notifier);
pr_info(PREFIX "%s: %d docks/bays found\n",
ACPI_DOCK_DRIVER_DESCRIPTION, dock_station_count);
return 0;
}
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