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