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       1                 :            : // SPDX-License-Identifier: GPL-2.0
       2                 :            : /*
       3                 :            :  * driver.c - centralized device driver management
       4                 :            :  *
       5                 :            :  * Copyright (c) 2002-3 Patrick Mochel
       6                 :            :  * Copyright (c) 2002-3 Open Source Development Labs
       7                 :            :  * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
       8                 :            :  * Copyright (c) 2007 Novell Inc.
       9                 :            :  */
      10                 :            : 
      11                 :            : #include <linux/device/driver.h>
      12                 :            : #include <linux/device.h>
      13                 :            : #include <linux/module.h>
      14                 :            : #include <linux/errno.h>
      15                 :            : #include <linux/slab.h>
      16                 :            : #include <linux/string.h>
      17                 :            : #include <linux/sysfs.h>
      18                 :            : #include "base.h"
      19                 :            : 
      20                 :          0 : static struct device *next_device(struct klist_iter *i)
      21                 :            : {
      22                 :          0 :         struct klist_node *n = klist_next(i);
      23                 :          0 :         struct device *dev = NULL;
      24                 :          0 :         struct device_private *dev_prv;
      25                 :            : 
      26   [ #  #  #  # ]:          0 :         if (n) {
      27                 :          0 :                 dev_prv = to_device_private_driver(n);
      28                 :          0 :                 dev = dev_prv->device;
      29                 :            :         }
      30                 :          0 :         return dev;
      31                 :            : }
      32                 :            : 
      33                 :            : /**
      34                 :            :  * driver_for_each_device - Iterator for devices bound to a driver.
      35                 :            :  * @drv: Driver we're iterating.
      36                 :            :  * @start: Device to begin with
      37                 :            :  * @data: Data to pass to the callback.
      38                 :            :  * @fn: Function to call for each device.
      39                 :            :  *
      40                 :            :  * Iterate over the @drv's list of devices calling @fn for each one.
      41                 :            :  */
      42                 :          0 : int driver_for_each_device(struct device_driver *drv, struct device *start,
      43                 :            :                            void *data, int (*fn)(struct device *, void *))
      44                 :            : {
      45                 :          0 :         struct klist_iter i;
      46                 :          0 :         struct device *dev;
      47                 :          0 :         int error = 0;
      48                 :            : 
      49         [ #  # ]:          0 :         if (!drv)
      50                 :            :                 return -EINVAL;
      51                 :            : 
      52         [ #  # ]:          0 :         klist_iter_init_node(&drv->p->klist_devices, &i,
      53                 :          0 :                              start ? &start->p->knode_driver : NULL);
      54   [ #  #  #  # ]:          0 :         while (!error && (dev = next_device(&i)))
      55                 :          0 :                 error = fn(dev, data);
      56                 :          0 :         klist_iter_exit(&i);
      57                 :          0 :         return error;
      58                 :            : }
      59                 :            : EXPORT_SYMBOL_GPL(driver_for_each_device);
      60                 :            : 
      61                 :            : /**
      62                 :            :  * driver_find_device - device iterator for locating a particular device.
      63                 :            :  * @drv: The device's driver
      64                 :            :  * @start: Device to begin with
      65                 :            :  * @data: Data to pass to match function
      66                 :            :  * @match: Callback function to check device
      67                 :            :  *
      68                 :            :  * This is similar to the driver_for_each_device() function above, but
      69                 :            :  * it returns a reference to a device that is 'found' for later use, as
      70                 :            :  * determined by the @match callback.
      71                 :            :  *
      72                 :            :  * The callback should return 0 if the device doesn't match and non-zero
      73                 :            :  * if it does.  If the callback returns non-zero, this function will
      74                 :            :  * return to the caller and not iterate over any more devices.
      75                 :            :  */
      76                 :          0 : struct device *driver_find_device(struct device_driver *drv,
      77                 :            :                                   struct device *start, const void *data,
      78                 :            :                                   int (*match)(struct device *dev, const void *data))
      79                 :            : {
      80                 :          0 :         struct klist_iter i;
      81                 :          0 :         struct device *dev;
      82                 :            : 
      83   [ #  #  #  # ]:          0 :         if (!drv || !drv->p)
      84                 :            :                 return NULL;
      85                 :            : 
      86         [ #  # ]:          0 :         klist_iter_init_node(&drv->p->klist_devices, &i,
      87                 :          0 :                              (start ? &start->p->knode_driver : NULL));
      88         [ #  # ]:          0 :         while ((dev = next_device(&i)))
      89   [ #  #  #  # ]:          0 :                 if (match(dev, data) && get_device(dev))
      90                 :            :                         break;
      91                 :          0 :         klist_iter_exit(&i);
      92                 :          0 :         return dev;
      93                 :            : }
      94                 :            : EXPORT_SYMBOL_GPL(driver_find_device);
      95                 :            : 
      96                 :            : /**
      97                 :            :  * driver_create_file - create sysfs file for driver.
      98                 :            :  * @drv: driver.
      99                 :            :  * @attr: driver attribute descriptor.
     100                 :            :  */
     101                 :       4654 : int driver_create_file(struct device_driver *drv,
     102                 :            :                        const struct driver_attribute *attr)
     103                 :            : {
     104                 :       4654 :         int error;
     105                 :            : 
     106         [ +  - ]:       4654 :         if (drv)
     107                 :       4654 :                 error = sysfs_create_file(&drv->p->kobj, &attr->attr);
     108                 :            :         else
     109                 :            :                 error = -EINVAL;
     110                 :       4654 :         return error;
     111                 :            : }
     112                 :            : EXPORT_SYMBOL_GPL(driver_create_file);
     113                 :            : 
     114                 :            : /**
     115                 :            :  * driver_remove_file - remove sysfs file for driver.
     116                 :            :  * @drv: driver.
     117                 :            :  * @attr: driver attribute descriptor.
     118                 :            :  */
     119                 :        117 : void driver_remove_file(struct device_driver *drv,
     120                 :            :                         const struct driver_attribute *attr)
     121                 :            : {
     122         [ +  - ]:        117 :         if (drv)
     123                 :        117 :                 sysfs_remove_file(&drv->p->kobj, &attr->attr);
     124                 :        117 : }
     125                 :            : EXPORT_SYMBOL_GPL(driver_remove_file);
     126                 :            : 
     127                 :       3068 : int driver_add_groups(struct device_driver *drv,
     128                 :            :                       const struct attribute_group **groups)
     129                 :            : {
     130                 :       1534 :         return sysfs_create_groups(&drv->p->kobj, groups);
     131                 :            : }
     132                 :            : 
     133                 :         78 : void driver_remove_groups(struct device_driver *drv,
     134                 :            :                           const struct attribute_group **groups)
     135                 :            : {
     136                 :         39 :         sysfs_remove_groups(&drv->p->kobj, groups);
     137                 :         39 : }
     138                 :            : 
     139                 :            : /**
     140                 :            :  * driver_register - register driver with bus
     141                 :            :  * @drv: driver to register
     142                 :            :  *
     143                 :            :  * We pass off most of the work to the bus_add_driver() call,
     144                 :            :  * since most of the things we have to do deal with the bus
     145                 :            :  * structures.
     146                 :            :  */
     147                 :       1534 : int driver_register(struct device_driver *drv)
     148                 :            : {
     149                 :       1534 :         int ret;
     150                 :       1534 :         struct device_driver *other;
     151                 :            : 
     152         [ -  + ]:       1534 :         if (!drv->bus->p) {
     153                 :          0 :                 pr_err("Driver '%s' was unable to register with bus_type '%s' because the bus was not initialized.\n",
     154                 :            :                            drv->name, drv->bus->name);
     155                 :          0 :                 return -EINVAL;
     156                 :            :         }
     157                 :            : 
     158   [ +  +  +  - ]:       1534 :         if ((drv->bus->probe && drv->probe) ||
     159   [ +  +  +  - ]:       1534 :             (drv->bus->remove && drv->remove) ||
     160   [ +  +  -  + ]:       1534 :             (drv->bus->shutdown && drv->shutdown))
     161                 :          0 :                 printk(KERN_WARNING "Driver '%s' needs updating - please use "
     162                 :            :                         "bus_type methods\n", drv->name);
     163                 :            : 
     164                 :       1534 :         other = driver_find(drv->name, drv->bus);
     165         [ -  + ]:       1534 :         if (other) {
     166                 :          0 :                 printk(KERN_ERR "Error: Driver '%s' is already registered, "
     167                 :            :                         "aborting...\n", drv->name);
     168                 :          0 :                 return -EBUSY;
     169                 :            :         }
     170                 :            : 
     171                 :       1534 :         ret = bus_add_driver(drv);
     172         [ +  - ]:       1534 :         if (ret)
     173                 :            :                 return ret;
     174                 :       1534 :         ret = driver_add_groups(drv, drv->groups);
     175         [ -  + ]:       1534 :         if (ret) {
     176                 :          0 :                 bus_remove_driver(drv);
     177                 :          0 :                 return ret;
     178                 :            :         }
     179                 :       1534 :         kobject_uevent(&drv->p->kobj, KOBJ_ADD);
     180                 :            : 
     181                 :       1534 :         return ret;
     182                 :            : }
     183                 :            : EXPORT_SYMBOL_GPL(driver_register);
     184                 :            : 
     185                 :            : /**
     186                 :            :  * driver_unregister - remove driver from system.
     187                 :            :  * @drv: driver.
     188                 :            :  *
     189                 :            :  * Again, we pass off most of the work to the bus-level call.
     190                 :            :  */
     191                 :         39 : void driver_unregister(struct device_driver *drv)
     192                 :            : {
     193   [ +  -  -  + ]:         39 :         if (!drv || !drv->p) {
     194                 :          0 :                 WARN(1, "Unexpected driver unregister!\n");
     195                 :          0 :                 return;
     196                 :            :         }
     197                 :         39 :         driver_remove_groups(drv, drv->groups);
     198                 :         39 :         bus_remove_driver(drv);
     199                 :            : }
     200                 :            : EXPORT_SYMBOL_GPL(driver_unregister);
     201                 :            : 
     202                 :            : /**
     203                 :            :  * driver_find - locate driver on a bus by its name.
     204                 :            :  * @name: name of the driver.
     205                 :            :  * @bus: bus to scan for the driver.
     206                 :            :  *
     207                 :            :  * Call kset_find_obj() to iterate over list of drivers on
     208                 :            :  * a bus to find driver by name. Return driver if found.
     209                 :            :  *
     210                 :            :  * This routine provides no locking to prevent the driver it returns
     211                 :            :  * from being unregistered or unloaded while the caller is using it.
     212                 :            :  * The caller is responsible for preventing this.
     213                 :            :  */
     214                 :       1534 : struct device_driver *driver_find(const char *name, struct bus_type *bus)
     215                 :            : {
     216                 :       1534 :         struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
     217                 :       1534 :         struct driver_private *priv;
     218                 :            : 
     219         [ -  + ]:       1534 :         if (k) {
     220                 :            :                 /* Drop reference added by kset_find_obj() */
     221                 :          0 :                 kobject_put(k);
     222                 :          0 :                 priv = to_driver(k);
     223                 :          0 :                 return priv->driver;
     224                 :            :         }
     225                 :            :         return NULL;
     226                 :            : }
     227                 :            : EXPORT_SYMBOL_GPL(driver_find);