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Subject[PATCH 2/7] ACPI / scan: Introduce common code for ACPI-based device hotplug
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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>
---
drivers/acpi/scan.c | 271 +++++++++++++++++++++++++++++++++++++-----------
include/acpi/acpi_bus.h | 7 +
2 files changed, 220 insertions(+), 58 deletions(-)

Index: test/include/acpi/acpi_bus.h
===================================================================
--- test.orig/include/acpi/acpi_bus.h
+++ test/include/acpi/acpi_bus.h
@@ -88,11 +88,18 @@ struct acpi_device;
* -----------------
*/

+struct acpi_hotplug_profile {
+ bool enabled:1;
+ bool uevents:1;
+ bool autoeject:1;
+};
+
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;
};

/*
Index: test/drivers/acpi/scan.c
===================================================================
--- test.orig/drivers/acpi/scan.c
+++ test/drivers/acpi/scan.c
@@ -107,32 +107,19 @@ acpi_device_modalias_show(struct device
}
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,
@@ -143,7 +130,7 @@ void acpi_bus_hot_remove_device(void *co
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;
@@ -161,18 +148,162 @@ void acpi_bus_hot_remove_device(void *co
*/
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;
+}
+
+static void acpi_bus_device_eject(void *context)
+{
+ acpi_handle handle = context;
+ struct acpi_device *device = NULL;
+ struct acpi_scan_handler *handler;
+ u32 ost_source = ACPI_NOTIFY_EJECT_REQUEST;
+ u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
+
+ mutex_lock(&acpi_scan_lock);

- /* Tell the firmware the hot-remove operation has failed. */
- acpi_evaluate_hotplug_ost(handle, ej_event->event,
- ost_code, NULL);
+ acpi_bus_get_device(handle, &device);
+ if (!device)
+ goto out;
+
+ handler = device->handler;
+ if (!handler || !handler->hotplug.enabled) {
+ ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
+ goto out;
}
+ acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
+ ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
+ if (handler->hotplug.uevents)
+ kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
+
+ if (handler->hotplug.autoeject) {
+ int error;
+
+ ost_source = ACPI_OST_EC_OSPM_EJECT;
+ get_device(&device->dev);
+ error = acpi_scan_hot_remove(device);
+ if (!error)
+ ost_code = ACPI_OST_SC_SUCCESS;
+ } else {
+ device->flags.eject_pending = true;
+ goto out_unlock;
+ }
+
+ out:
+ acpi_evaluate_hotplug_ost(handle, ost_source, ost_code, NULL);
+
+ out_unlock:
+ mutex_unlock(&acpi_scan_lock);
+}
+
+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);
+ ost_source = ACPI_OST_EC_OSPM_INSERTION;
+ 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.uevents)
+ 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;
+ u32 ost_code = ACPI_OST_SC_SUCCESS;
+ int error;
+
+ mutex_lock(&acpi_scan_lock);
+
+ error = acpi_scan_hot_remove(device);
+ if (error)
+ ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
+
+ acpi_evaluate_hotplug_ost(handle, ej_event->event, ost_code, NULL);
+
mutex_unlock(&acpi_scan_lock);
kfree(context);
- return;
}
EXPORT_SYMBOL(acpi_bus_hot_remove_device);

@@ -206,50 +337,48 @@ 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;
+ u32 ost_code;
+ 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;
}
-
- status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event);
- if (ACPI_FAILURE(status)) {
- put_device(&acpi_device->dev);
- kfree(ej_event);
+ acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source,
+ ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
+ get_device(&acpi_device->dev);
+ ret = acpi_scan_hot_remove(acpi_device);
+ if (ret) {
+ ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
+ } else {
+ ost_code = ACPI_OST_SC_SUCCESS;
+ ret = count;
}
-err:
+ acpi_evaluate_hotplug_ost(acpi_device->handle, ACPI_OST_EC_OSPM_EJECT,
+ ost_code, NULL);
+
+ mutex_unlock(&acpi_scan_lock);
return ret;
}

@@ -1548,6 +1677,30 @@ static struct acpi_scan_handler *acpi_sc
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)
{
@@ -1570,6 +1723,8 @@ static acpi_status acpi_bus_check_add(ac
return AE_OK;
}

+ acpi_scan_init_hotplug(handle);
+
if (!(sta & ACPI_STA_DEVICE_PRESENT) &&
!(sta & ACPI_STA_DEVICE_FUNCTIONING)) {
struct acpi_device_wakeup wakeup;


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