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/*-------------------------------------------------------------------------*/
29USB_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
45static 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
53static struct usb_gadget_strings stringtab_dev = {
54	.language	= 0x0409,	/* en-us */
55	.strings	= strings_dev,
56};
57
58static struct usb_gadget_strings *dev_strings[] = {
59	&stringtab_dev,
60	NULL,
61};
62
63static 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
79static const struct usb_descriptor_header *otg_desc[2];
80
81/*-------------------------------------------------------------------------*/
82
83/* Module */
84MODULE_DESCRIPTION(GS_VERSION_NAME);
85MODULE_AUTHOR("Al Borchers");
86MODULE_AUTHOR("David Brownell");
87MODULE_LICENSE("GPL");
88
89static bool use_acm = true;
90module_param(use_acm, bool, 0);
91MODULE_PARM_DESC(use_acm, "Use CDC ACM, default=yes");
92
93static bool use_obex = false;
94module_param(use_obex, bool, 0);
95MODULE_PARM_DESC(use_obex, "Use CDC OBEX, default=no");
96
97static unsigned n_ports = 1;
98module_param(n_ports, uint, 0);
99MODULE_PARM_DESC(n_ports, "number of ports to create, default=1");
100
101static bool enable = true;
102
103static int switch_gserial_enable(bool do_enable);
104
105static 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
124static const struct kernel_param_ops enable_ops = {
125	.set = enable_set,
126	.get = param_get_bool,
127};
128
129module_param_cb(enable, &enable_ops, &enable, 0644);
130
131/*-------------------------------------------------------------------------*/
132
133static 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
140static struct usb_function_instance *fi_serial[MAX_U_SERIAL_PORTS];
141static struct usb_function *f_serial[MAX_U_SERIAL_PORTS];
142
143static 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
174err_add_func:
175	usb_put_function(f_serial[i]);
176err_get_func:
177	usb_put_function_instance(fi_serial[i]);
178
179fail:
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	}
187out:
188	return ret;
189}
190
191static 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;
243fail1:
244	kfree(otg_desc[0]);
245	otg_desc[0] = NULL;
246fail:
247	return status;
248}
249
250static 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
265static 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
274static 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
287static 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}
318module_init(gserial_init);
319
320static void __exit gserial_cleanup(void)
321{
322	if (enable)
323		usb_composite_unregister(&gserial_driver);
324}
325module_exit(gserial_cleanup);
326