xref: /openbmc/linux/drivers/usb/gadget/legacy/serial.c (revision 9726bfcd)
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 /*-------------------------------------------------------------------------*/
101 
102 static struct usb_configuration serial_config_driver = {
103 	/* .label = f(use_acm) */
104 	/* .bConfigurationValue = f(use_acm) */
105 	/* .iConfiguration = DYNAMIC */
106 	.bmAttributes	= USB_CONFIG_ATT_SELFPOWER,
107 };
108 
109 static struct usb_function_instance *fi_serial[MAX_U_SERIAL_PORTS];
110 static struct usb_function *f_serial[MAX_U_SERIAL_PORTS];
111 
112 static int serial_register_ports(struct usb_composite_dev *cdev,
113 		struct usb_configuration *c, const char *f_name)
114 {
115 	int i;
116 	int ret;
117 
118 	ret = usb_add_config_only(cdev, c);
119 	if (ret)
120 		goto out;
121 
122 	for (i = 0; i < n_ports; i++) {
123 
124 		fi_serial[i] = usb_get_function_instance(f_name);
125 		if (IS_ERR(fi_serial[i])) {
126 			ret = PTR_ERR(fi_serial[i]);
127 			goto fail;
128 		}
129 
130 		f_serial[i] = usb_get_function(fi_serial[i]);
131 		if (IS_ERR(f_serial[i])) {
132 			ret = PTR_ERR(f_serial[i]);
133 			goto err_get_func;
134 		}
135 
136 		ret = usb_add_function(c, f_serial[i]);
137 		if (ret)
138 			goto err_add_func;
139 	}
140 
141 	return 0;
142 
143 err_add_func:
144 	usb_put_function(f_serial[i]);
145 err_get_func:
146 	usb_put_function_instance(fi_serial[i]);
147 
148 fail:
149 	i--;
150 	while (i >= 0) {
151 		usb_remove_function(c, f_serial[i]);
152 		usb_put_function(f_serial[i]);
153 		usb_put_function_instance(fi_serial[i]);
154 		i--;
155 	}
156 out:
157 	return ret;
158 }
159 
160 static int gs_bind(struct usb_composite_dev *cdev)
161 {
162 	int			status;
163 
164 	/* Allocate string descriptor numbers ... note that string
165 	 * contents can be overridden by the composite_dev glue.
166 	 */
167 
168 	status = usb_string_ids_tab(cdev, strings_dev);
169 	if (status < 0)
170 		goto fail;
171 	device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
172 	device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
173 	status = strings_dev[STRING_DESCRIPTION_IDX].id;
174 	serial_config_driver.iConfiguration = status;
175 
176 	if (gadget_is_otg(cdev->gadget)) {
177 		if (!otg_desc[0]) {
178 			struct usb_descriptor_header *usb_desc;
179 
180 			usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
181 			if (!usb_desc) {
182 				status = -ENOMEM;
183 				goto fail;
184 			}
185 			usb_otg_descriptor_init(cdev->gadget, usb_desc);
186 			otg_desc[0] = usb_desc;
187 			otg_desc[1] = NULL;
188 		}
189 		serial_config_driver.descriptors = otg_desc;
190 		serial_config_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
191 	}
192 
193 	/* register our configuration */
194 	if (use_acm) {
195 		status  = serial_register_ports(cdev, &serial_config_driver,
196 				"acm");
197 		usb_ep_autoconfig_reset(cdev->gadget);
198 	} else if (use_obex)
199 		status = serial_register_ports(cdev, &serial_config_driver,
200 				"obex");
201 	else {
202 		status = serial_register_ports(cdev, &serial_config_driver,
203 				"gser");
204 	}
205 	if (status < 0)
206 		goto fail1;
207 
208 	usb_composite_overwrite_options(cdev, &coverwrite);
209 	INFO(cdev, "%s\n", GS_VERSION_NAME);
210 
211 	return 0;
212 fail1:
213 	kfree(otg_desc[0]);
214 	otg_desc[0] = NULL;
215 fail:
216 	return status;
217 }
218 
219 static int gs_unbind(struct usb_composite_dev *cdev)
220 {
221 	int i;
222 
223 	for (i = 0; i < n_ports; i++) {
224 		usb_put_function(f_serial[i]);
225 		usb_put_function_instance(fi_serial[i]);
226 	}
227 
228 	kfree(otg_desc[0]);
229 	otg_desc[0] = NULL;
230 
231 	return 0;
232 }
233 
234 static struct usb_composite_driver gserial_driver = {
235 	.name		= "g_serial",
236 	.dev		= &device_desc,
237 	.strings	= dev_strings,
238 	.max_speed	= USB_SPEED_SUPER,
239 	.bind		= gs_bind,
240 	.unbind		= gs_unbind,
241 };
242 
243 static int __init init(void)
244 {
245 	/* We *could* export two configs; that'd be much cleaner...
246 	 * but neither of these product IDs was defined that way.
247 	 */
248 	if (use_acm) {
249 		serial_config_driver.label = "CDC ACM config";
250 		serial_config_driver.bConfigurationValue = 2;
251 		device_desc.bDeviceClass = USB_CLASS_COMM;
252 		device_desc.idProduct =
253 				cpu_to_le16(GS_CDC_PRODUCT_ID);
254 	} else if (use_obex) {
255 		serial_config_driver.label = "CDC OBEX config";
256 		serial_config_driver.bConfigurationValue = 3;
257 		device_desc.bDeviceClass = USB_CLASS_COMM;
258 		device_desc.idProduct =
259 			cpu_to_le16(GS_CDC_OBEX_PRODUCT_ID);
260 	} else {
261 		serial_config_driver.label = "Generic Serial config";
262 		serial_config_driver.bConfigurationValue = 1;
263 		device_desc.bDeviceClass = USB_CLASS_VENDOR_SPEC;
264 		device_desc.idProduct =
265 				cpu_to_le16(GS_PRODUCT_ID);
266 	}
267 	strings_dev[STRING_DESCRIPTION_IDX].s = serial_config_driver.label;
268 
269 	return usb_composite_probe(&gserial_driver);
270 }
271 module_init(init);
272 
273 static void __exit cleanup(void)
274 {
275 	usb_composite_unregister(&gserial_driver);
276 }
277 module_exit(cleanup);
278