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-rw-r--r--drivers/base/driver.c303
1 files changed, 303 insertions, 0 deletions
diff --git a/drivers/base/driver.c b/drivers/base/driver.c
new file mode 100644
index 000000000..676b6275d
--- /dev/null
+++ b/drivers/base/driver.c
@@ -0,0 +1,303 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * driver.c - centralized device driver management
+ *
+ * Copyright (c) 2002-3 Patrick Mochel
+ * Copyright (c) 2002-3 Open Source Development Labs
+ * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
+ * Copyright (c) 2007 Novell Inc.
+ */
+
+#include <linux/device/driver.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include "base.h"
+
+static struct device *next_device(struct klist_iter *i)
+{
+ struct klist_node *n = klist_next(i);
+ struct device *dev = NULL;
+ struct device_private *dev_prv;
+
+ if (n) {
+ dev_prv = to_device_private_driver(n);
+ dev = dev_prv->device;
+ }
+ return dev;
+}
+
+/**
+ * driver_set_override() - Helper to set or clear driver override.
+ * @dev: Device to change
+ * @override: Address of string to change (e.g. &device->driver_override);
+ * The contents will be freed and hold newly allocated override.
+ * @s: NUL-terminated string, new driver name to force a match, pass empty
+ * string to clear it ("" or "\n", where the latter is only for sysfs
+ * interface).
+ * @len: length of @s
+ *
+ * Helper to set or clear driver override in a device, intended for the cases
+ * when the driver_override field is allocated by driver/bus code.
+ *
+ * Returns: 0 on success or a negative error code on failure.
+ */
+int driver_set_override(struct device *dev, const char **override,
+ const char *s, size_t len)
+{
+ const char *new, *old;
+ char *cp;
+
+ if (!override || !s)
+ return -EINVAL;
+
+ /*
+ * The stored value will be used in sysfs show callback (sysfs_emit()),
+ * which has a length limit of PAGE_SIZE and adds a trailing newline.
+ * Thus we can store one character less to avoid truncation during sysfs
+ * show.
+ */
+ if (len >= (PAGE_SIZE - 1))
+ return -EINVAL;
+
+ /*
+ * Compute the real length of the string in case userspace sends us a
+ * bunch of \0 characters like python likes to do.
+ */
+ len = strlen(s);
+
+ if (!len) {
+ /* Empty string passed - clear override */
+ device_lock(dev);
+ old = *override;
+ *override = NULL;
+ device_unlock(dev);
+ kfree(old);
+
+ return 0;
+ }
+
+ cp = strnchr(s, len, '\n');
+ if (cp)
+ len = cp - s;
+
+ new = kstrndup(s, len, GFP_KERNEL);
+ if (!new)
+ return -ENOMEM;
+
+ device_lock(dev);
+ old = *override;
+ if (cp != s) {
+ *override = new;
+ } else {
+ /* "\n" passed - clear override */
+ kfree(new);
+ *override = NULL;
+ }
+ device_unlock(dev);
+
+ kfree(old);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(driver_set_override);
+
+/**
+ * driver_for_each_device - Iterator for devices bound to a driver.
+ * @drv: Driver we're iterating.
+ * @start: Device to begin with
+ * @data: Data to pass to the callback.
+ * @fn: Function to call for each device.
+ *
+ * Iterate over the @drv's list of devices calling @fn for each one.
+ */
+int driver_for_each_device(struct device_driver *drv, struct device *start,
+ void *data, int (*fn)(struct device *, void *))
+{
+ struct klist_iter i;
+ struct device *dev;
+ int error = 0;
+
+ if (!drv)
+ return -EINVAL;
+
+ klist_iter_init_node(&drv->p->klist_devices, &i,
+ start ? &start->p->knode_driver : NULL);
+ while (!error && (dev = next_device(&i)))
+ error = fn(dev, data);
+ klist_iter_exit(&i);
+ return error;
+}
+EXPORT_SYMBOL_GPL(driver_for_each_device);
+
+/**
+ * driver_find_device - device iterator for locating a particular device.
+ * @drv: The device's driver
+ * @start: Device to begin with
+ * @data: Data to pass to match function
+ * @match: Callback function to check device
+ *
+ * This is similar to the driver_for_each_device() function above, but
+ * it returns a reference to a device that is 'found' for later use, as
+ * determined by the @match callback.
+ *
+ * The callback should return 0 if the device doesn't match and non-zero
+ * if it does. If the callback returns non-zero, this function will
+ * return to the caller and not iterate over any more devices.
+ */
+struct device *driver_find_device(struct device_driver *drv,
+ struct device *start, const void *data,
+ int (*match)(struct device *dev, const void *data))
+{
+ struct klist_iter i;
+ struct device *dev;
+
+ if (!drv || !drv->p)
+ return NULL;
+
+ klist_iter_init_node(&drv->p->klist_devices, &i,
+ (start ? &start->p->knode_driver : NULL));
+ while ((dev = next_device(&i)))
+ if (match(dev, data) && get_device(dev))
+ break;
+ klist_iter_exit(&i);
+ return dev;
+}
+EXPORT_SYMBOL_GPL(driver_find_device);
+
+/**
+ * driver_create_file - create sysfs file for driver.
+ * @drv: driver.
+ * @attr: driver attribute descriptor.
+ */
+int driver_create_file(struct device_driver *drv,
+ const struct driver_attribute *attr)
+{
+ int error;
+
+ if (drv)
+ error = sysfs_create_file(&drv->p->kobj, &attr->attr);
+ else
+ error = -EINVAL;
+ return error;
+}
+EXPORT_SYMBOL_GPL(driver_create_file);
+
+/**
+ * driver_remove_file - remove sysfs file for driver.
+ * @drv: driver.
+ * @attr: driver attribute descriptor.
+ */
+void driver_remove_file(struct device_driver *drv,
+ const struct driver_attribute *attr)
+{
+ if (drv)
+ sysfs_remove_file(&drv->p->kobj, &attr->attr);
+}
+EXPORT_SYMBOL_GPL(driver_remove_file);
+
+int driver_add_groups(struct device_driver *drv,
+ const struct attribute_group **groups)
+{
+ return sysfs_create_groups(&drv->p->kobj, groups);
+}
+
+void driver_remove_groups(struct device_driver *drv,
+ const struct attribute_group **groups)
+{
+ sysfs_remove_groups(&drv->p->kobj, groups);
+}
+
+/**
+ * driver_register - register driver with bus
+ * @drv: driver to register
+ *
+ * We pass off most of the work to the bus_add_driver() call,
+ * since most of the things we have to do deal with the bus
+ * structures.
+ */
+int driver_register(struct device_driver *drv)
+{
+ int ret;
+ struct device_driver *other;
+
+ if (!drv->bus->p) {
+ pr_err("Driver '%s' was unable to register with bus_type '%s' because the bus was not initialized.\n",
+ drv->name, drv->bus->name);
+ return -EINVAL;
+ }
+
+ if ((drv->bus->probe && drv->probe) ||
+ (drv->bus->remove && drv->remove) ||
+ (drv->bus->shutdown && drv->shutdown))
+ pr_warn("Driver '%s' needs updating - please use "
+ "bus_type methods\n", drv->name);
+
+ other = driver_find(drv->name, drv->bus);
+ if (other) {
+ pr_err("Error: Driver '%s' is already registered, "
+ "aborting...\n", drv->name);
+ return -EBUSY;
+ }
+
+ ret = bus_add_driver(drv);
+ if (ret)
+ return ret;
+ ret = driver_add_groups(drv, drv->groups);
+ if (ret) {
+ bus_remove_driver(drv);
+ return ret;
+ }
+ kobject_uevent(&drv->p->kobj, KOBJ_ADD);
+ deferred_probe_extend_timeout();
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(driver_register);
+
+/**
+ * driver_unregister - remove driver from system.
+ * @drv: driver.
+ *
+ * Again, we pass off most of the work to the bus-level call.
+ */
+void driver_unregister(struct device_driver *drv)
+{
+ if (!drv || !drv->p) {
+ WARN(1, "Unexpected driver unregister!\n");
+ return;
+ }
+ driver_remove_groups(drv, drv->groups);
+ bus_remove_driver(drv);
+}
+EXPORT_SYMBOL_GPL(driver_unregister);
+
+/**
+ * driver_find - locate driver on a bus by its name.
+ * @name: name of the driver.
+ * @bus: bus to scan for the driver.
+ *
+ * Call kset_find_obj() to iterate over list of drivers on
+ * a bus to find driver by name. Return driver if found.
+ *
+ * This routine provides no locking to prevent the driver it returns
+ * from being unregistered or unloaded while the caller is using it.
+ * The caller is responsible for preventing this.
+ */
+struct device_driver *driver_find(const char *name, struct bus_type *bus)
+{
+ struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
+ struct driver_private *priv;
+
+ if (k) {
+ /* Drop reference added by kset_find_obj() */
+ kobject_put(k);
+ priv = to_driver(k);
+ return priv->driver;
+ }
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(driver_find);