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 
auxiliary_match_id(const struct auxiliary_device_id * id,const struct auxiliary_device * auxdev)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 
auxiliary_match(struct device * dev,struct device_driver * drv)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 
auxiliary_uevent(struct device * dev,struct kobj_uevent_env * env)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 
auxiliary_bus_probe(struct device * dev)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 
auxiliary_bus_remove(struct device * dev)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 
auxiliary_bus_shutdown(struct device * dev)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  */
auxiliary_device_init(struct auxiliary_device * auxdev)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  */
__auxiliary_device_add(struct auxiliary_device * auxdev,const char * modname)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  */
auxiliary_find_device(struct device * start,const void * data,int (* match)(struct device * dev,const void * data))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  */
__auxiliary_driver_register(struct auxiliary_driver * auxdrv,struct module * owner,const char * modname)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  */
auxiliary_driver_unregister(struct auxiliary_driver * auxdrv)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 
auxiliary_bus_init(void)268 void __init auxiliary_bus_init(void)
269 {
270 	WARN_ON(bus_register(&auxiliary_bus_type));
271 }
272