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8cb5d216 EB |
1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* | |
3 | * Copyright 2021 Xillybus Ltd, http://xillybus.com | |
4 | * | |
5 | * Driver for the Xillybus class | |
6 | */ | |
7 | ||
8 | #include <linux/types.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/device.h> | |
11 | #include <linux/fs.h> | |
12 | #include <linux/cdev.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/list.h> | |
15 | #include <linux/mutex.h> | |
16 | ||
17 | #include "xillybus_class.h" | |
18 | ||
19 | MODULE_DESCRIPTION("Driver for Xillybus class"); | |
20 | MODULE_AUTHOR("Eli Billauer, Xillybus Ltd."); | |
8cb5d216 EB |
21 | MODULE_ALIAS("xillybus_class"); |
22 | MODULE_LICENSE("GPL v2"); | |
23 | ||
24 | static DEFINE_MUTEX(unit_mutex); | |
25 | static LIST_HEAD(unit_list); | |
26 | static struct class *xillybus_class; | |
27 | ||
28 | #define UNITNAMELEN 16 | |
29 | ||
30 | struct xilly_unit { | |
31 | struct list_head list_entry; | |
32 | void *private_data; | |
33 | ||
34 | struct cdev *cdev; | |
35 | char name[UNITNAMELEN]; | |
36 | int major; | |
37 | int lowest_minor; | |
38 | int num_nodes; | |
39 | }; | |
40 | ||
41 | int xillybus_init_chrdev(struct device *dev, | |
42 | const struct file_operations *fops, | |
43 | struct module *owner, | |
44 | void *private_data, | |
45 | unsigned char *idt, unsigned int len, | |
46 | int num_nodes, | |
47 | const char *prefix, bool enumerate) | |
48 | { | |
49 | int rc; | |
50 | dev_t mdev; | |
51 | int i; | |
52 | char devname[48]; | |
53 | ||
54 | struct device *device; | |
55 | size_t namelen; | |
56 | struct xilly_unit *unit, *u; | |
57 | ||
58 | unit = kzalloc(sizeof(*unit), GFP_KERNEL); | |
59 | ||
60 | if (!unit) | |
61 | return -ENOMEM; | |
62 | ||
63 | mutex_lock(&unit_mutex); | |
64 | ||
65 | if (!enumerate) | |
66 | snprintf(unit->name, UNITNAMELEN, "%s", prefix); | |
67 | ||
68 | for (i = 0; enumerate; i++) { | |
69 | snprintf(unit->name, UNITNAMELEN, "%s_%02d", | |
70 | prefix, i); | |
71 | ||
72 | enumerate = false; | |
73 | list_for_each_entry(u, &unit_list, list_entry) | |
74 | if (!strcmp(unit->name, u->name)) { | |
75 | enumerate = true; | |
76 | break; | |
77 | } | |
78 | } | |
79 | ||
80 | rc = alloc_chrdev_region(&mdev, 0, num_nodes, unit->name); | |
81 | ||
82 | if (rc) { | |
83 | dev_warn(dev, "Failed to obtain major/minors"); | |
84 | goto fail_obtain; | |
85 | } | |
86 | ||
87 | unit->major = MAJOR(mdev); | |
88 | unit->lowest_minor = MINOR(mdev); | |
89 | unit->num_nodes = num_nodes; | |
90 | unit->private_data = private_data; | |
91 | ||
92 | unit->cdev = cdev_alloc(); | |
93 | if (!unit->cdev) { | |
94 | rc = -ENOMEM; | |
95 | goto unregister_chrdev; | |
96 | } | |
97 | unit->cdev->ops = fops; | |
98 | unit->cdev->owner = owner; | |
99 | ||
100 | rc = cdev_add(unit->cdev, MKDEV(unit->major, unit->lowest_minor), | |
101 | unit->num_nodes); | |
102 | if (rc) { | |
103 | dev_err(dev, "Failed to add cdev.\n"); | |
104 | /* kobject_put() is normally done by cdev_del() */ | |
105 | kobject_put(&unit->cdev->kobj); | |
106 | goto unregister_chrdev; | |
107 | } | |
108 | ||
109 | for (i = 0; i < num_nodes; i++) { | |
110 | namelen = strnlen(idt, len); | |
111 | ||
112 | if (namelen == len) { | |
113 | dev_err(dev, "IDT's list of names is too short. This is exceptionally weird, because its CRC is OK\n"); | |
114 | rc = -ENODEV; | |
115 | goto unroll_device_create; | |
116 | } | |
117 | ||
118 | snprintf(devname, sizeof(devname), "%s_%s", | |
119 | unit->name, idt); | |
120 | ||
121 | len -= namelen + 1; | |
122 | idt += namelen + 1; | |
123 | ||
124 | device = device_create(xillybus_class, | |
125 | NULL, | |
126 | MKDEV(unit->major, | |
127 | i + unit->lowest_minor), | |
128 | NULL, | |
129 | "%s", devname); | |
130 | ||
131 | if (IS_ERR(device)) { | |
132 | dev_err(dev, "Failed to create %s device. Aborting.\n", | |
133 | devname); | |
134 | rc = -ENODEV; | |
135 | goto unroll_device_create; | |
136 | } | |
137 | } | |
138 | ||
139 | if (len) { | |
140 | dev_err(dev, "IDT's list of names is too long. This is exceptionally weird, because its CRC is OK\n"); | |
141 | rc = -ENODEV; | |
142 | goto unroll_device_create; | |
143 | } | |
144 | ||
145 | list_add_tail(&unit->list_entry, &unit_list); | |
146 | ||
147 | dev_info(dev, "Created %d device files.\n", num_nodes); | |
148 | ||
149 | mutex_unlock(&unit_mutex); | |
150 | ||
151 | return 0; | |
152 | ||
153 | unroll_device_create: | |
154 | for (i--; i >= 0; i--) | |
155 | device_destroy(xillybus_class, MKDEV(unit->major, | |
156 | i + unit->lowest_minor)); | |
157 | ||
158 | cdev_del(unit->cdev); | |
159 | ||
160 | unregister_chrdev: | |
161 | unregister_chrdev_region(MKDEV(unit->major, unit->lowest_minor), | |
162 | unit->num_nodes); | |
163 | ||
164 | fail_obtain: | |
165 | mutex_unlock(&unit_mutex); | |
166 | ||
167 | kfree(unit); | |
168 | ||
169 | return rc; | |
170 | } | |
171 | EXPORT_SYMBOL(xillybus_init_chrdev); | |
172 | ||
173 | void xillybus_cleanup_chrdev(void *private_data, | |
174 | struct device *dev) | |
175 | { | |
176 | int minor; | |
177 | struct xilly_unit *unit; | |
178 | bool found = false; | |
179 | ||
180 | mutex_lock(&unit_mutex); | |
181 | ||
182 | list_for_each_entry(unit, &unit_list, list_entry) | |
183 | if (unit->private_data == private_data) { | |
184 | found = true; | |
185 | break; | |
186 | } | |
187 | ||
188 | if (!found) { | |
189 | dev_err(dev, "Weird bug: Failed to find unit\n"); | |
190 | mutex_unlock(&unit_mutex); | |
191 | return; | |
192 | } | |
193 | ||
194 | for (minor = unit->lowest_minor; | |
195 | minor < (unit->lowest_minor + unit->num_nodes); | |
196 | minor++) | |
197 | device_destroy(xillybus_class, MKDEV(unit->major, minor)); | |
198 | ||
199 | cdev_del(unit->cdev); | |
200 | ||
201 | unregister_chrdev_region(MKDEV(unit->major, unit->lowest_minor), | |
202 | unit->num_nodes); | |
203 | ||
204 | dev_info(dev, "Removed %d device files.\n", | |
205 | unit->num_nodes); | |
206 | ||
207 | list_del(&unit->list_entry); | |
208 | kfree(unit); | |
209 | ||
210 | mutex_unlock(&unit_mutex); | |
211 | } | |
212 | EXPORT_SYMBOL(xillybus_cleanup_chrdev); | |
213 | ||
214 | int xillybus_find_inode(struct inode *inode, | |
215 | void **private_data, int *index) | |
216 | { | |
217 | int minor = iminor(inode); | |
218 | int major = imajor(inode); | |
219 | struct xilly_unit *unit; | |
220 | bool found = false; | |
221 | ||
222 | mutex_lock(&unit_mutex); | |
223 | ||
224 | list_for_each_entry(unit, &unit_list, list_entry) | |
225 | if (unit->major == major && | |
226 | minor >= unit->lowest_minor && | |
227 | minor < (unit->lowest_minor + unit->num_nodes)) { | |
228 | found = true; | |
229 | break; | |
230 | } | |
231 | ||
232 | mutex_unlock(&unit_mutex); | |
233 | ||
234 | if (!found) | |
235 | return -ENODEV; | |
236 | ||
237 | *private_data = unit->private_data; | |
238 | *index = minor - unit->lowest_minor; | |
239 | ||
240 | return 0; | |
241 | } | |
242 | EXPORT_SYMBOL(xillybus_find_inode); | |
243 | ||
244 | static int __init xillybus_class_init(void) | |
245 | { | |
246 | xillybus_class = class_create(THIS_MODULE, "xillybus"); | |
247 | ||
248 | if (IS_ERR(xillybus_class)) { | |
249 | pr_warn("Failed to register xillybus class\n"); | |
250 | ||
251 | return PTR_ERR(xillybus_class); | |
252 | } | |
253 | return 0; | |
254 | } | |
255 | ||
256 | static void __exit xillybus_class_exit(void) | |
257 | { | |
258 | class_destroy(xillybus_class); | |
259 | } | |
260 | ||
261 | module_init(xillybus_class_init); | |
262 | module_exit(xillybus_class_exit); |