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