1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * serial.c -- USB gadget serial driver
4 *
5 * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
6 * Copyright (C) 2008 by David Brownell
7 * Copyright (C) 2008 by Nokia Corporation
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/device.h>
12 #include <linux/kstrtox.h>
13 #include <linux/module.h>
14 #include <linux/tty.h>
15 #include <linux/tty_flip.h>
16
17 #include "u_serial.h"
18
19
20 /* Defines */
21
22 #define GS_VERSION_STR "v2.4"
23 #define GS_VERSION_NUM 0x2400
24
25 #define GS_LONG_NAME "Gadget Serial"
26 #define GS_VERSION_NAME GS_LONG_NAME " " GS_VERSION_STR
27
28 /*-------------------------------------------------------------------------*/
29 USB_GADGET_COMPOSITE_OPTIONS();
30
31 /* Thanks to NetChip Technologies for donating this product ID.
32 *
33 * DO NOT REUSE THESE IDs with a protocol-incompatible driver!! Ever!!
34 * Instead: allocate your own, using normal USB-IF procedures.
35 */
36 #define GS_VENDOR_ID 0x0525 /* NetChip */
37 #define GS_PRODUCT_ID 0xa4a6 /* Linux-USB Serial Gadget */
38 #define GS_CDC_PRODUCT_ID 0xa4a7 /* ... as CDC-ACM */
39 #define GS_CDC_OBEX_PRODUCT_ID 0xa4a9 /* ... as CDC-OBEX */
40
41 /* string IDs are assigned dynamically */
42
43 #define STRING_DESCRIPTION_IDX USB_GADGET_FIRST_AVAIL_IDX
44
45 static struct usb_string strings_dev[] = {
46 [USB_GADGET_MANUFACTURER_IDX].s = "",
47 [USB_GADGET_PRODUCT_IDX].s = GS_VERSION_NAME,
48 [USB_GADGET_SERIAL_IDX].s = "",
49 [STRING_DESCRIPTION_IDX].s = NULL /* updated; f(use_acm) */,
50 { } /* end of list */
51 };
52
53 static struct usb_gadget_strings stringtab_dev = {
54 .language = 0x0409, /* en-us */
55 .strings = strings_dev,
56 };
57
58 static struct usb_gadget_strings *dev_strings[] = {
59 &stringtab_dev,
60 NULL,
61 };
62
63 static struct usb_device_descriptor device_desc = {
64 .bLength = USB_DT_DEVICE_SIZE,
65 .bDescriptorType = USB_DT_DEVICE,
66 /* .bcdUSB = DYNAMIC */
67 /* .bDeviceClass = f(use_acm) */
68 .bDeviceSubClass = 0,
69 .bDeviceProtocol = 0,
70 /* .bMaxPacketSize0 = f(hardware) */
71 .idVendor = cpu_to_le16(GS_VENDOR_ID),
72 /* .idProduct = f(use_acm) */
73 .bcdDevice = cpu_to_le16(GS_VERSION_NUM),
74 /* .iManufacturer = DYNAMIC */
75 /* .iProduct = DYNAMIC */
76 .bNumConfigurations = 1,
77 };
78
79 static const struct usb_descriptor_header *otg_desc[2];
80
81 /*-------------------------------------------------------------------------*/
82
83 /* Module */
84 MODULE_DESCRIPTION(GS_VERSION_NAME);
85 MODULE_AUTHOR("Al Borchers");
86 MODULE_AUTHOR("David Brownell");
87 MODULE_LICENSE("GPL");
88
89 static bool use_acm = true;
90 module_param(use_acm, bool, 0);
91 MODULE_PARM_DESC(use_acm, "Use CDC ACM, default=yes");
92
93 static bool use_obex = false;
94 module_param(use_obex, bool, 0);
95 MODULE_PARM_DESC(use_obex, "Use CDC OBEX, default=no");
96
97 static unsigned n_ports = 1;
98 module_param(n_ports, uint, 0);
99 MODULE_PARM_DESC(n_ports, "number of ports to create, default=1");
100
101 static bool enable = true;
102
103 static int switch_gserial_enable(bool do_enable);
104
enable_set(const char * s,const struct kernel_param * kp)105 static int enable_set(const char *s, const struct kernel_param *kp)
106 {
107 bool do_enable;
108 int ret;
109
110 if (!s) /* called for no-arg enable == default */
111 return 0;
112
113 ret = kstrtobool(s, &do_enable);
114 if (ret || enable == do_enable)
115 return ret;
116
117 ret = switch_gserial_enable(do_enable);
118 if (!ret)
119 enable = do_enable;
120
121 return ret;
122 }
123
124 static const struct kernel_param_ops enable_ops = {
125 .set = enable_set,
126 .get = param_get_bool,
127 };
128
129 module_param_cb(enable, &enable_ops, &enable, 0644);
130
131 /*-------------------------------------------------------------------------*/
132
133 static struct usb_configuration serial_config_driver = {
134 /* .label = f(use_acm) */
135 /* .bConfigurationValue = f(use_acm) */
136 /* .iConfiguration = DYNAMIC */
137 .bmAttributes = USB_CONFIG_ATT_SELFPOWER,
138 };
139
140 static struct usb_function_instance *fi_serial[MAX_U_SERIAL_PORTS];
141 static struct usb_function *f_serial[MAX_U_SERIAL_PORTS];
142
serial_register_ports(struct usb_composite_dev * cdev,struct usb_configuration * c,const char * f_name)143 static int serial_register_ports(struct usb_composite_dev *cdev,
144 struct usb_configuration *c, const char *f_name)
145 {
146 int i;
147 int ret;
148
149 ret = usb_add_config_only(cdev, c);
150 if (ret)
151 goto out;
152
153 for (i = 0; i < n_ports; i++) {
154
155 fi_serial[i] = usb_get_function_instance(f_name);
156 if (IS_ERR(fi_serial[i])) {
157 ret = PTR_ERR(fi_serial[i]);
158 goto fail;
159 }
160
161 f_serial[i] = usb_get_function(fi_serial[i]);
162 if (IS_ERR(f_serial[i])) {
163 ret = PTR_ERR(f_serial[i]);
164 goto err_get_func;
165 }
166
167 ret = usb_add_function(c, f_serial[i]);
168 if (ret)
169 goto err_add_func;
170 }
171
172 return 0;
173
174 err_add_func:
175 usb_put_function(f_serial[i]);
176 err_get_func:
177 usb_put_function_instance(fi_serial[i]);
178
179 fail:
180 i--;
181 while (i >= 0) {
182 usb_remove_function(c, f_serial[i]);
183 usb_put_function(f_serial[i]);
184 usb_put_function_instance(fi_serial[i]);
185 i--;
186 }
187 out:
188 return ret;
189 }
190
gs_bind(struct usb_composite_dev * cdev)191 static int gs_bind(struct usb_composite_dev *cdev)
192 {
193 int status;
194
195 /* Allocate string descriptor numbers ... note that string
196 * contents can be overridden by the composite_dev glue.
197 */
198
199 status = usb_string_ids_tab(cdev, strings_dev);
200 if (status < 0)
201 goto fail;
202 device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
203 device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
204 status = strings_dev[STRING_DESCRIPTION_IDX].id;
205 serial_config_driver.iConfiguration = status;
206
207 if (gadget_is_otg(cdev->gadget)) {
208 if (!otg_desc[0]) {
209 struct usb_descriptor_header *usb_desc;
210
211 usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
212 if (!usb_desc) {
213 status = -ENOMEM;
214 goto fail;
215 }
216 usb_otg_descriptor_init(cdev->gadget, usb_desc);
217 otg_desc[0] = usb_desc;
218 otg_desc[1] = NULL;
219 }
220 serial_config_driver.descriptors = otg_desc;
221 serial_config_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
222 }
223
224 /* register our configuration */
225 if (use_acm) {
226 status = serial_register_ports(cdev, &serial_config_driver,
227 "acm");
228 usb_ep_autoconfig_reset(cdev->gadget);
229 } else if (use_obex)
230 status = serial_register_ports(cdev, &serial_config_driver,
231 "obex");
232 else {
233 status = serial_register_ports(cdev, &serial_config_driver,
234 "gser");
235 }
236 if (status < 0)
237 goto fail1;
238
239 usb_composite_overwrite_options(cdev, &coverwrite);
240 INFO(cdev, "%s\n", GS_VERSION_NAME);
241
242 return 0;
243 fail1:
244 kfree(otg_desc[0]);
245 otg_desc[0] = NULL;
246 fail:
247 return status;
248 }
249
gs_unbind(struct usb_composite_dev * cdev)250 static int gs_unbind(struct usb_composite_dev *cdev)
251 {
252 int i;
253
254 for (i = 0; i < n_ports; i++) {
255 usb_put_function(f_serial[i]);
256 usb_put_function_instance(fi_serial[i]);
257 }
258
259 kfree(otg_desc[0]);
260 otg_desc[0] = NULL;
261
262 return 0;
263 }
264
265 static struct usb_composite_driver gserial_driver = {
266 .name = "g_serial",
267 .dev = &device_desc,
268 .strings = dev_strings,
269 .max_speed = USB_SPEED_SUPER,
270 .bind = gs_bind,
271 .unbind = gs_unbind,
272 };
273
switch_gserial_enable(bool do_enable)274 static int switch_gserial_enable(bool do_enable)
275 {
276 if (!serial_config_driver.label)
277 /* gserial_init() was not called, yet */
278 return 0;
279
280 if (do_enable)
281 return usb_composite_probe(&gserial_driver);
282
283 usb_composite_unregister(&gserial_driver);
284 return 0;
285 }
286
gserial_init(void)287 static int __init gserial_init(void)
288 {
289 /* We *could* export two configs; that'd be much cleaner...
290 * but neither of these product IDs was defined that way.
291 */
292 if (use_acm) {
293 serial_config_driver.label = "CDC ACM config";
294 serial_config_driver.bConfigurationValue = 2;
295 device_desc.bDeviceClass = USB_CLASS_COMM;
296 device_desc.idProduct =
297 cpu_to_le16(GS_CDC_PRODUCT_ID);
298 } else if (use_obex) {
299 serial_config_driver.label = "CDC OBEX config";
300 serial_config_driver.bConfigurationValue = 3;
301 device_desc.bDeviceClass = USB_CLASS_COMM;
302 device_desc.idProduct =
303 cpu_to_le16(GS_CDC_OBEX_PRODUCT_ID);
304 } else {
305 serial_config_driver.label = "Generic Serial config";
306 serial_config_driver.bConfigurationValue = 1;
307 device_desc.bDeviceClass = USB_CLASS_VENDOR_SPEC;
308 device_desc.idProduct =
309 cpu_to_le16(GS_PRODUCT_ID);
310 }
311 strings_dev[STRING_DESCRIPTION_IDX].s = serial_config_driver.label;
312
313 if (!enable)
314 return 0;
315
316 return usb_composite_probe(&gserial_driver);
317 }
318 module_init(gserial_init);
319
gserial_cleanup(void)320 static void __exit gserial_cleanup(void)
321 {
322 if (enable)
323 usb_composite_unregister(&gserial_driver);
324 }
325 module_exit(gserial_cleanup);
326