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ACPI / scan: Introduce common code for ACPI-based device hotplug
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Multiple drivers handling hotplug-capable ACPI device nodes install
notify handlers covering the same types of events in a very similar
way.  Moreover, those handlers are installed in separate namespace
walks, although that really should be done during namespace scans
carried out by acpi_bus_scan().  This leads to substantial code
duplication, unnecessary overhead and behavior that is hard to
follow.

For this reason, introduce common code in drivers/acpi/scan.c for
handling hotplug-related notification and carrying out device
insertion and eject operations in a generic fashion, such that it
may be used by all of the relevant drivers in the future.  To cover
the existing differences between those drivers introduce struct
acpi_hotplug_profile for representing collections of hotplug
settings associated with different ACPI scan handlers that can be
used by the drivers to make the common code reflect their current
behavior.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Tested-by: Toshi Kani <toshi.kani@hp.com>
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Rafael J. Wysocki committed Mar 4, 2013
1 parent c569807 commit a33ec39
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Showing 2 changed files with 228 additions and 53 deletions.
269 changes: 216 additions & 53 deletions drivers/acpi/scan.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -107,32 +107,19 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
}
static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);

/**
* acpi_bus_hot_remove_device: hot-remove a device and its children
* @context: struct acpi_eject_event pointer (freed in this func)
*
* Hot-remove a device and its children. This function frees up the
* memory space passed by arg context, so that the caller may call
* this function asynchronously through acpi_os_hotplug_execute().
*/
void acpi_bus_hot_remove_device(void *context)
static int acpi_scan_hot_remove(struct acpi_device *device)
{
struct acpi_eject_event *ej_event = context;
struct acpi_device *device = ej_event->device;
acpi_handle handle = device->handle;
acpi_handle temp;
acpi_handle not_used;
struct acpi_object_list arg_list;
union acpi_object arg;
acpi_status status = AE_OK;
u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */

mutex_lock(&acpi_scan_lock);
acpi_status status;

/* If there is no handle, the device node has been unregistered. */
if (!device->handle) {
if (!handle) {
dev_dbg(&device->dev, "ACPI handle missing\n");
put_device(&device->dev);
goto out;
return -EINVAL;
}

ACPI_DEBUG_PRINT((ACPI_DB_INFO,
Expand All @@ -143,7 +130,7 @@ void acpi_bus_hot_remove_device(void *context)
put_device(&device->dev);
device = NULL;

if (ACPI_SUCCESS(acpi_get_handle(handle, "_LCK", &temp))) {
if (ACPI_SUCCESS(acpi_get_handle(handle, "_LCK", &not_used))) {
arg_list.count = 1;
arg_list.pointer = &arg;
arg.type = ACPI_TYPE_INTEGER;
Expand All @@ -161,18 +148,158 @@ void acpi_bus_hot_remove_device(void *context)
*/
status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND)
if (status == AE_NOT_FOUND) {
return -ENODEV;
} else {
acpi_handle_warn(handle, "Eject failed\n");
return -EIO;
}
}
return 0;
}

/* Tell the firmware the hot-remove operation has failed. */
acpi_evaluate_hotplug_ost(handle, ej_event->event,
ost_code, NULL);
static void acpi_bus_device_eject(void *context)
{
acpi_handle handle = context;
struct acpi_device *device = NULL;
struct acpi_scan_handler *handler;
u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;

mutex_lock(&acpi_scan_lock);

acpi_bus_get_device(handle, &device);
if (!device)
goto err_out;

handler = device->handler;
if (!handler || !handler->hotplug.enabled) {
ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
goto err_out;
}
acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
if (handler->hotplug.mode == AHM_CONTAINER) {
device->flags.eject_pending = true;
kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
} else {
int error;

get_device(&device->dev);
error = acpi_scan_hot_remove(device);
if (error)
goto err_out;
}

out:
mutex_unlock(&acpi_scan_lock);
kfree(context);
return;

err_out:
acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST, ost_code,
NULL);
goto out;
}

static void acpi_scan_bus_device_check(acpi_handle handle, u32 ost_source)
{
struct acpi_device *device = NULL;
u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
int error;

mutex_lock(&acpi_scan_lock);

acpi_bus_get_device(handle, &device);
if (device) {
dev_warn(&device->dev, "Attempt to re-insert\n");
goto out;
}
acpi_evaluate_hotplug_ost(handle, ost_source,
ACPI_OST_SC_INSERT_IN_PROGRESS, NULL);
error = acpi_bus_scan(handle);
if (error) {
acpi_handle_warn(handle, "Namespace scan failure\n");
goto out;
}
error = acpi_bus_get_device(handle, &device);
if (error) {
acpi_handle_warn(handle, "Missing device node object\n");
goto out;
}
ost_code = ACPI_OST_SC_SUCCESS;
if (device->handler && device->handler->hotplug.mode == AHM_CONTAINER)
kobject_uevent(&device->dev.kobj, KOBJ_ONLINE);

out:
acpi_evaluate_hotplug_ost(handle, ost_source, ost_code, NULL);
mutex_unlock(&acpi_scan_lock);
}

static void acpi_scan_bus_check(void *context)
{
acpi_scan_bus_device_check((acpi_handle)context,
ACPI_NOTIFY_BUS_CHECK);
}

static void acpi_scan_device_check(void *context)
{
acpi_scan_bus_device_check((acpi_handle)context,
ACPI_NOTIFY_DEVICE_CHECK);
}

static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *not_used)
{
acpi_osd_exec_callback callback;
acpi_status status;

switch (type) {
case ACPI_NOTIFY_BUS_CHECK:
acpi_handle_debug(handle, "ACPI_NOTIFY_BUS_CHECK event\n");
callback = acpi_scan_bus_check;
break;
case ACPI_NOTIFY_DEVICE_CHECK:
acpi_handle_debug(handle, "ACPI_NOTIFY_DEVICE_CHECK event\n");
callback = acpi_scan_device_check;
break;
case ACPI_NOTIFY_EJECT_REQUEST:
acpi_handle_debug(handle, "ACPI_NOTIFY_EJECT_REQUEST event\n");
callback = acpi_bus_device_eject;
break;
default:
/* non-hotplug event; possibly handled by other handler */
return;
}
status = acpi_os_hotplug_execute(callback, handle);
if (ACPI_FAILURE(status))
acpi_evaluate_hotplug_ost(handle, type,
ACPI_OST_SC_NON_SPECIFIC_FAILURE,
NULL);
}

/**
* acpi_bus_hot_remove_device: hot-remove a device and its children
* @context: struct acpi_eject_event pointer (freed in this func)
*
* Hot-remove a device and its children. This function frees up the
* memory space passed by arg context, so that the caller may call
* this function asynchronously through acpi_os_hotplug_execute().
*/
void acpi_bus_hot_remove_device(void *context)
{
struct acpi_eject_event *ej_event = context;
struct acpi_device *device = ej_event->device;
acpi_handle handle = device->handle;
int error;

mutex_lock(&acpi_scan_lock);

error = acpi_scan_hot_remove(device);
if (error && handle)
acpi_evaluate_hotplug_ost(handle, ej_event->event,
ACPI_OST_SC_NON_SPECIFIC_FAILURE,
NULL);

mutex_unlock(&acpi_scan_lock);
kfree(context);
}
EXPORT_SYMBOL(acpi_bus_hot_remove_device);

Expand Down Expand Up @@ -206,51 +333,61 @@ static ssize_t
acpi_eject_store(struct device *d, struct device_attribute *attr,
const char *buf, size_t count)
{
int ret = count;
acpi_status status;
acpi_object_type type = 0;
struct acpi_device *acpi_device = to_acpi_device(d);
struct acpi_eject_event *ej_event;
acpi_object_type not_used;
acpi_status status;
u32 ost_source;
int ret;

if ((!count) || (buf[0] != '1')) {
if (!count || buf[0] != '1')
return -EINVAL;
}
if (!acpi_device->driver && !acpi_device->handler) {
ret = -ENODEV;
goto err;
}
status = acpi_get_type(acpi_device->handle, &type);
if (ACPI_FAILURE(status) || (!acpi_device->flags.ejectable)) {
ret = -ENODEV;
goto err;
}

ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
if (!ej_event) {
ret = -ENOMEM;
goto err;
}
if ((!acpi_device->handler || !acpi_device->handler->hotplug.enabled)
&& !acpi_device->driver)
return -ENODEV;

status = acpi_get_type(acpi_device->handle, &not_used);
if (ACPI_FAILURE(status) || !acpi_device->flags.ejectable)
return -ENODEV;

mutex_lock(&acpi_scan_lock);

get_device(&acpi_device->dev);
ej_event->device = acpi_device;
if (acpi_device->flags.eject_pending) {
/* event originated from ACPI eject notification */
ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
/* ACPI eject notification event. */
ost_source = ACPI_NOTIFY_EJECT_REQUEST;
acpi_device->flags.eject_pending = 0;
} else {
/* event originated from user */
ej_event->event = ACPI_OST_EC_OSPM_EJECT;
(void) acpi_evaluate_hotplug_ost(acpi_device->handle,
ej_event->event, ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
/* Eject initiated by user space. */
ost_source = ACPI_OST_EC_OSPM_EJECT;
}

ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
if (!ej_event) {
ret = -ENOMEM;
goto err_out;
}
acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source,
ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
ej_event->device = acpi_device;
ej_event->event = ost_source;
get_device(&acpi_device->dev);
status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event);
if (ACPI_FAILURE(status)) {
put_device(&acpi_device->dev);
kfree(ej_event);
ret = status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
goto err_out;
}
err:
ret = count;

out:
mutex_unlock(&acpi_scan_lock);
return ret;

err_out:
acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source,
ACPI_OST_SC_NON_SPECIFIC_FAILURE, NULL);
goto out;
}

static DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
Expand Down Expand Up @@ -1555,6 +1692,30 @@ static struct acpi_scan_handler *acpi_scan_match_handler(char *idstr,
return NULL;
}

static void acpi_scan_init_hotplug(acpi_handle handle)
{
struct acpi_device_info *info;
struct acpi_scan_handler *handler;

if (ACPI_FAILURE(acpi_get_object_info(handle, &info)))
return;

if (!(info->valid & ACPI_VALID_HID)) {
kfree(info);
return;
}

/*
* This relies on the fact that acpi_install_notify_handler() will not
* install the same notify handler routine twice for the same handle.
*/
handler = acpi_scan_match_handler(info->hardware_id.string, NULL);
kfree(info);
if (handler && handler->hotplug.enabled)
acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
acpi_hotplug_notify_cb, NULL);
}

static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,
void *not_used, void **return_value)
{
Expand All @@ -1577,6 +1738,8 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,
return AE_OK;
}

acpi_scan_init_hotplug(handle);

if (!(sta & ACPI_STA_DEVICE_PRESENT) &&
!(sta & ACPI_STA_DEVICE_FUNCTIONING)) {
struct acpi_device_wakeup wakeup;
Expand Down
12 changes: 12 additions & 0 deletions include/acpi/acpi_bus.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -88,11 +88,23 @@ struct acpi_device;
* -----------------
*/

enum acpi_hotplug_mode {
AHM_GENERIC = 0,
AHM_CONTAINER,
AHM_COUNT
};

struct acpi_hotplug_profile {
bool enabled:1;
enum acpi_hotplug_mode mode;
};

struct acpi_scan_handler {
const struct acpi_device_id *ids;
struct list_head list_node;
int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id);
void (*detach)(struct acpi_device *dev);
struct acpi_hotplug_profile hotplug;
};

/*
Expand Down

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