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
 20static 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
 39static 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
 47static 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
 58static 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
 63static 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
 82static int 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	return 0;
 92}
 93
 94static void auxiliary_bus_shutdown(struct device *dev)
 95{
 96	struct auxiliary_driver *auxdrv = NULL;
 97	struct auxiliary_device *auxdev;
 98
 99	if (dev->driver) {
100		auxdrv = to_auxiliary_drv(dev->driver);
101		auxdev = to_auxiliary_dev(dev);
102	}
103
104	if (auxdrv && auxdrv->shutdown)
105		auxdrv->shutdown(auxdev);
106}
107
108static struct bus_type auxiliary_bus_type = {
109	.name = "auxiliary",
110	.probe = auxiliary_bus_probe,
111	.remove = auxiliary_bus_remove,
112	.shutdown = auxiliary_bus_shutdown,
113	.match = auxiliary_match,
114	.uevent = auxiliary_uevent,
115	.pm = &auxiliary_dev_pm_ops,
116};
117
118/**
119 * auxiliary_device_init - check auxiliary_device and initialize
120 * @auxdev: auxiliary device struct
121 *
122 * This is the first step in the two-step process to register an
123 * auxiliary_device.
124 *
125 * When this function returns an error code, then the device_initialize will
126 * *not* have been performed, and the caller will be responsible to free any
127 * memory allocated for the auxiliary_device in the error path directly.
128 *
129 * It returns 0 on success.  On success, the device_initialize has been
130 * performed.  After this point any error unwinding will need to include a call
131 * to auxiliary_device_uninit().  In this post-initialize error scenario, a call
132 * to the device's .release callback will be triggered, and all memory clean-up
133 * is expected to be handled there.
134 */
135int auxiliary_device_init(struct auxiliary_device *auxdev)
136{
137	struct device *dev = &auxdev->dev;
138
139	if (!dev->parent) {
140		pr_err("auxiliary_device has a NULL dev->parent\n");
141		return -EINVAL;
142	}
143
144	if (!auxdev->name) {
145		pr_err("auxiliary_device has a NULL name\n");
146		return -EINVAL;
147	}
148
149	dev->bus = &auxiliary_bus_type;
150	device_initialize(&auxdev->dev);
151	return 0;
152}
153EXPORT_SYMBOL_GPL(auxiliary_device_init);
154
155/**
156 * __auxiliary_device_add - add an auxiliary bus device
157 * @auxdev: auxiliary bus device to add to the bus
158 * @modname: name of the parent device's driver module
159 *
160 * This is the second step in the two-step process to register an
161 * auxiliary_device.
162 *
163 * This function must be called after a successful call to
164 * auxiliary_device_init(), which will perform the device_initialize.  This
165 * means that if this returns an error code, then a call to
166 * auxiliary_device_uninit() must be performed so that the .release callback
167 * will be triggered to free the memory associated with the auxiliary_device.
168 *
169 * The expectation is that users will call the "auxiliary_device_add" macro so
170 * that the caller's KBUILD_MODNAME is automatically inserted for the modname
171 * parameter.  Only if a user requires a custom name would this version be
172 * called directly.
173 */
174int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname)
175{
176	struct device *dev = &auxdev->dev;
177	int ret;
178
179	if (!modname) {
180		dev_err(dev, "auxiliary device modname is NULL\n");
181		return -EINVAL;
182	}
183
184	ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id);
185	if (ret) {
186		dev_err(dev, "auxiliary device dev_set_name failed: %d\n", ret);
187		return ret;
188	}
189
190	ret = device_add(dev);
191	if (ret)
192		dev_err(dev, "adding auxiliary device failed!: %d\n", ret);
193
194	return ret;
195}
196EXPORT_SYMBOL_GPL(__auxiliary_device_add);
197
198/**
199 * auxiliary_find_device - auxiliary device iterator for locating a particular device.
200 * @start: Device to begin with
201 * @data: Data to pass to match function
202 * @match: Callback function to check device
203 *
204 * This function returns a reference to a device that is 'found'
205 * for later use, as determined by the @match callback.
206 *
207 * The callback should return 0 if the device doesn't match and non-zero
208 * if it does.  If the callback returns non-zero, this function will
209 * return to the caller and not iterate over any more devices.
210 */
211struct auxiliary_device *auxiliary_find_device(struct device *start,
212					       const void *data,
213					       int (*match)(struct device *dev, const void *data))
214{
215	struct device *dev;
216
217	dev = bus_find_device(&auxiliary_bus_type, start, data, match);
218	if (!dev)
219		return NULL;
220
221	return to_auxiliary_dev(dev);
222}
223EXPORT_SYMBOL_GPL(auxiliary_find_device);
224
225/**
226 * __auxiliary_driver_register - register a driver for auxiliary bus devices
227 * @auxdrv: auxiliary_driver structure
228 * @owner: owning module/driver
229 * @modname: KBUILD_MODNAME for parent driver
230 */
231int __auxiliary_driver_register(struct auxiliary_driver *auxdrv,
232				struct module *owner, const char *modname)
233{
234	int ret;
235
236	if (WARN_ON(!auxdrv->probe) || WARN_ON(!auxdrv->id_table))
237		return -EINVAL;
238
239	if (auxdrv->name)
240		auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s.%s", modname,
241						auxdrv->name);
242	else
243		auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s", modname);
244	if (!auxdrv->driver.name)
245		return -ENOMEM;
246
247	auxdrv->driver.owner = owner;
248	auxdrv->driver.bus = &auxiliary_bus_type;
249	auxdrv->driver.mod_name = modname;
250
251	ret = driver_register(&auxdrv->driver);
252	if (ret)
253		kfree(auxdrv->driver.name);
254
255	return ret;
256}
257EXPORT_SYMBOL_GPL(__auxiliary_driver_register);
258
259/**
260 * auxiliary_driver_unregister - unregister a driver
261 * @auxdrv: auxiliary_driver structure
262 */
263void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv)
264{
265	driver_unregister(&auxdrv->driver);
266	kfree(auxdrv->driver.name);
267}
268EXPORT_SYMBOL_GPL(auxiliary_driver_unregister);
269
270void __init auxiliary_bus_init(void)
271{
272	WARN_ON(bus_register(&auxiliary_bus_type));
273}