drivers/base/auxiliary.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2019-2020 Intel Corporation
   4  *
   5  * Please see Documentation/driver-api/auxiliary_bus.rst for more information.
   6  */
   7
   8 #define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__
   9
  10 #include <linux/device.h>
  11 #include <linux/init.h>
  12 #include <linux/slab.h>
  13 #include <linux/module.h>
  14 #include <linux/pm_domain.h>
  15 #include <linux/pm_runtime.h>
  16 #include <linux/string.h>
  17 #include <linux/auxiliary_bus.h>
  18
  19 static const struct auxiliary_device_id *auxiliary_match_id(const struct auxiliary_device_id *id,
  20                                                             const struct auxiliary_device *auxdev)
  21 {
  22         for (; id->name[0]; id++) {
  23                 const char *p = strrchr(dev_name(&auxdev->dev), '.');
  24                 int match_size;
  25
  26                 if (!p)
  27                         continue;
  28                 match_size = p - dev_name(&auxdev->dev);
  29
  30                 /* use dev_name(&auxdev->dev) prefix before last '.' char to match to */
  31                 if (strlen(id->name) == match_size &&
  32                     !strncmp(dev_name(&auxdev->dev), id->name, match_size))
  33                         return id;
  34         }
  35         return NULL;
  36 }
  37
  38 static int auxiliary_match(struct device *dev, struct device_driver *drv)
  39 {
  40         struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
  41         struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv);
  42
  43         return !!auxiliary_match_id(auxdrv->id_table, auxdev);
  44 }
  45
  46 static int auxiliary_uevent(struct device *dev, struct kobj_uevent_env *env)
  47 {
  48         const char *name, *p;
  49
  50         name = dev_name(dev);
  51         p = strrchr(name, '.');
  52
  53         return add_uevent_var(env, "MODALIAS=%s%.*s", AUXILIARY_MODULE_PREFIX,
  54                               (int)(p - name), name);
  55 }
  56
  57 static const struct dev_pm_ops auxiliary_dev_pm_ops = {
  58         SET_RUNTIME_PM_OPS(pm_generic_runtime_suspend, pm_generic_runtime_resume, NULL)
  59         SET_SYSTEM_SLEEP_PM_OPS(pm_generic_suspend, pm_generic_resume)
  60 };
  61
  62 static int auxiliary_bus_probe(struct device *dev)
  63 {
  64         struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
  65         struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
  66         int ret;
  67
  68         ret = dev_pm_domain_attach(dev, true);
  69         if (ret) {
  70                 dev_warn(dev, "Failed to attach to PM Domain : %d\n", ret);
  71                 return ret;
  72         }
  73
  74         ret = auxdrv->probe(auxdev, auxiliary_match_id(auxdrv->id_table, auxdev));
  75         if (ret)
  76                 dev_pm_domain_detach(dev, true);
  77
  78         return ret;
  79 }
  80
  81 static int auxiliary_bus_remove(struct device *dev)
  82 {
  83         struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
  84         struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
  85
  86         if (auxdrv->remove)
  87                 auxdrv->remove(auxdev);
  88         dev_pm_domain_detach(dev, true);
  89
  90         return 0;
  91 }
  92
  93 static void auxiliary_bus_shutdown(struct device *dev)
  94 {
  95         struct auxiliary_driver *auxdrv = NULL;
  96         struct auxiliary_device *auxdev;
  97
  98         if (dev->driver) {
  99                 auxdrv = to_auxiliary_drv(dev->driver);
 100                 auxdev = to_auxiliary_dev(dev);
 101         }
 102
 103         if (auxdrv && auxdrv->shutdown)
 104                 auxdrv->shutdown(auxdev);
 105 }
 106
 107 static struct bus_type auxiliary_bus_type = {
 108         .name = "auxiliary",
 109         .probe = auxiliary_bus_probe,
 110         .remove = auxiliary_bus_remove,
 111         .shutdown = auxiliary_bus_shutdown,
 112         .match = auxiliary_match,
 113         .uevent = auxiliary_uevent,
 114         .pm = &auxiliary_dev_pm_ops,
 115 };
 116
 117 /**
 118  * auxiliary_device_init - check auxiliary_device and initialize
 119  * @auxdev: auxiliary device struct
 120  *
 121  * This is the first step in the two-step process to register an
 122  * auxiliary_device.
 123  *
 124  * When this function returns an error code, then the device_initialize will
 125  * *not* have been performed, and the caller will be responsible to free any
 126  * memory allocated for the auxiliary_device in the error path directly.
 127  *
 128  * It returns 0 on success.  On success, the device_initialize has been
 129  * performed.  After this point any error unwinding will need to include a call
 130  * to auxiliary_device_uninit().  In this post-initialize error scenario, a call
 131  * to the device's .release callback will be triggered, and all memory clean-up
 132  * is expected to be handled there.
 133  */
 134 int auxiliary_device_init(struct auxiliary_device *auxdev)
 135 {
 136         struct device *dev = &auxdev->dev;
 137
 138         if (!dev->parent) {
 139                 pr_err("auxiliary_device has a NULL dev->parent\n");
 140                 return -EINVAL;
 141         }
 142
 143         if (!auxdev->name) {
 144                 pr_err("auxiliary_device has a NULL name\n");
 145                 return -EINVAL;
 146         }
 147
 148         dev->bus = &auxiliary_bus_type;
 149         device_initialize(&auxdev->dev);
 150         return 0;
 151 }
 152 EXPORT_SYMBOL_GPL(auxiliary_device_init);
 153
 154 /**
 155  * __auxiliary_device_add - add an auxiliary bus device
 156  * @auxdev: auxiliary bus device to add to the bus
 157  * @modname: name of the parent device's driver module
 158  *
 159  * This is the second step in the two-step process to register an
 160  * auxiliary_device.
 161  *
 162  * This function must be called after a successful call to
 163  * auxiliary_device_init(), which will perform the device_initialize.  This
 164  * means that if this returns an error code, then a call to
 165  * auxiliary_device_uninit() must be performed so that the .release callback
 166  * will be triggered to free the memory associated with the auxiliary_device.
 167  *
 168  * The expectation is that users will call the "auxiliary_device_add" macro so
 169  * that the caller's KBUILD_MODNAME is automatically inserted for the modname
 170  * parameter.  Only if a user requires a custom name would this version be
 171  * called directly.
 172  */
 173 int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname)
 174 {
 175         struct device *dev = &auxdev->dev;
 176         int ret;
 177
 178         if (!modname) {
 179                 dev_err(dev, "auxiliary device modname is NULL\n");
 180                 return -EINVAL;
 181         }
 182
 183         ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id);
 184         if (ret) {
 185                 dev_err(dev, "auxiliary device dev_set_name failed: %d\n", ret);
 186                 return ret;
 187         }
 188
 189         ret = device_add(dev);
 190         if (ret)
 191                 dev_err(dev, "adding auxiliary device failed!: %d\n", ret);
 192
 193         return ret;
 194 }
 195 EXPORT_SYMBOL_GPL(__auxiliary_device_add);
 196
 197 /**
 198  * auxiliary_find_device - auxiliary device iterator for locating a particular device.
 199  * @start: Device to begin with
 200  * @data: Data to pass to match function
 201  * @match: Callback function to check device
 202  *
 203  * This function returns a reference to a device that is 'found'
 204  * for later use, as determined by the @match callback.
 205  *
 206  * The callback should return 0 if the device doesn't match and non-zero
 207  * if it does.  If the callback returns non-zero, this function will
 208  * return to the caller and not iterate over any more devices.
 209  */
 210 struct auxiliary_device *auxiliary_find_device(struct device *start,
 211                                                const void *data,
 212                                                int (*match)(struct device *dev, const void *data))
 213 {
 214         struct device *dev;
 215
 216         dev = bus_find_device(&auxiliary_bus_type, start, data, match);
 217         if (!dev)
 218                 return NULL;
 219
 220         return to_auxiliary_dev(dev);
 221 }
 222 EXPORT_SYMBOL_GPL(auxiliary_find_device);
 223
 224 /**
 225  * __auxiliary_driver_register - register a driver for auxiliary bus devices
 226  * @auxdrv: auxiliary_driver structure
 227  * @owner: owning module/driver
 228  * @modname: KBUILD_MODNAME for parent driver
 229  */
 230 int __auxiliary_driver_register(struct auxiliary_driver *auxdrv,
 231                                 struct module *owner, const char *modname)
 232 {
 233         if (WARN_ON(!auxdrv->probe) || WARN_ON(!auxdrv->id_table))
 234                 return -EINVAL;
 235
 236         if (auxdrv->name)
 237                 auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s.%s", modname,
 238                                                 auxdrv->name);
 239         else
 240                 auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s", modname);
 241         if (!auxdrv->driver.name)
 242                 return -ENOMEM;
 243
 244         auxdrv->driver.owner = owner;
 245         auxdrv->driver.bus = &auxiliary_bus_type;
 246         auxdrv->driver.mod_name = modname;
 247
 248         return driver_register(&auxdrv->driver);
 249 }
 250 EXPORT_SYMBOL_GPL(__auxiliary_driver_register);
 251
 252 /**
 253  * auxiliary_driver_unregister - unregister a driver
 254  * @auxdrv: auxiliary_driver structure
 255  */
 256 void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv)
 257 {
 258         driver_unregister(&auxdrv->driver);
 259         kfree(auxdrv->driver.name);
 260 }
 261 EXPORT_SYMBOL_GPL(auxiliary_driver_unregister);
 262
 263 static int __init auxiliary_bus_init(void)
 264 {
 265         return bus_register(&auxiliary_bus_type);
 266 }
 267
 268 static void __exit auxiliary_bus_exit(void)
 269 {
 270         bus_unregister(&auxiliary_bus_type);
 271 }
 272
 273 module_init(auxiliary_bus_init);
 274 module_exit(auxiliary_bus_exit);
 275
 276 MODULE_LICENSE("GPL v2");
 277 MODULE_DESCRIPTION("Auxiliary Bus");
 278 MODULE_AUTHOR("David Ertman <david.m.ertman@intel.com>");
 279 MODULE_AUTHOR("Kiran Patil <kiran.patil@intel.com>");