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/*-------------------------------------------------------------------------*/
28USB_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
44static 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
52static struct usb_gadget_strings stringtab_dev = {
53	.language	= 0x0409,	/* en-us */
54	.strings	= strings_dev,
55};
56
57static struct usb_gadget_strings *dev_strings[] = {
58	&stringtab_dev,
59	NULL,
60};
61
62static 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
78static const struct usb_descriptor_header *otg_desc[2];
79
80/*-------------------------------------------------------------------------*/
81
82/* Module */
83MODULE_DESCRIPTION(GS_VERSION_NAME);
84MODULE_AUTHOR("Al Borchers");
85MODULE_AUTHOR("David Brownell");
86MODULE_LICENSE("GPL");
87
88static bool use_acm = true;
89module_param(use_acm, bool, 0);
90MODULE_PARM_DESC(use_acm, "Use CDC ACM, default=yes");
91
92static bool use_obex = false;
93module_param(use_obex, bool, 0);
94MODULE_PARM_DESC(use_obex, "Use CDC OBEX, default=no");
95
96static unsigned n_ports = 1;
97module_param(n_ports, uint, 0);
98MODULE_PARM_DESC(n_ports, "number of ports to create, default=1");
99
100static bool enable = true;
101
102static int switch_gserial_enable(bool do_enable);
103
104static 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
123static const struct kernel_param_ops enable_ops = {
124	.set = enable_set,
125	.get = param_get_bool,
126};
127
128module_param_cb(enable, &enable_ops, &enable, 0644);
129
130/*-------------------------------------------------------------------------*/
131
132static 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
139static struct usb_function_instance *fi_serial[MAX_U_SERIAL_PORTS];
140static struct usb_function *f_serial[MAX_U_SERIAL_PORTS];
141
142static 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
173err_add_func:
174	usb_put_function(f_serial[i]);
175err_get_func:
176	usb_put_function_instance(fi_serial[i]);
177
178fail:
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	}
186out:
187	return ret;
188}
189
190static 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;
242fail1:
243	kfree(otg_desc[0]);
244	otg_desc[0] = NULL;
245fail:
246	return status;
247}
248
249static 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
264static 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
273static 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
286static 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}
317module_init(init);
318
319static void __exit cleanup(void)
320{
321	if (enable)
322		usb_composite_unregister(&gserial_driver);
323}
324module_exit(cleanup);
325