xref: /linux/drivers/usb/gadget/function/f_serial.c (revision b85d45947951d23cb22d90caecf4c1eb81342c96)
1 /*
2  * f_serial.c - generic USB serial function driver
3  *
4  * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
5  * Copyright (C) 2008 by David Brownell
6  * Copyright (C) 2008 by Nokia Corporation
7  *
8  * This software is distributed under the terms of the GNU General
9  * Public License ("GPL") as published by the Free Software Foundation,
10  * either version 2 of that License or (at your option) any later version.
11  */
12 
13 #include <linux/slab.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/device.h>
17 
18 #include "u_serial.h"
19 
20 
21 /*
22  * This function packages a simple "generic serial" port with no real
23  * control mechanisms, just raw data transfer over two bulk endpoints.
24  *
25  * Because it's not standardized, this isn't as interoperable as the
26  * CDC ACM driver.  However, for many purposes it's just as functional
27  * if you can arrange appropriate host side drivers.
28  */
29 
30 struct f_gser {
31 	struct gserial			port;
32 	u8				data_id;
33 	u8				port_num;
34 };
35 
36 static inline struct f_gser *func_to_gser(struct usb_function *f)
37 {
38 	return container_of(f, struct f_gser, port.func);
39 }
40 
41 /*-------------------------------------------------------------------------*/
42 
43 /* interface descriptor: */
44 
45 static struct usb_interface_descriptor gser_interface_desc = {
46 	.bLength =		USB_DT_INTERFACE_SIZE,
47 	.bDescriptorType =	USB_DT_INTERFACE,
48 	/* .bInterfaceNumber = DYNAMIC */
49 	.bNumEndpoints =	2,
50 	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
51 	.bInterfaceSubClass =	0,
52 	.bInterfaceProtocol =	0,
53 	/* .iInterface = DYNAMIC */
54 };
55 
56 /* full speed support: */
57 
58 static struct usb_endpoint_descriptor gser_fs_in_desc = {
59 	.bLength =		USB_DT_ENDPOINT_SIZE,
60 	.bDescriptorType =	USB_DT_ENDPOINT,
61 	.bEndpointAddress =	USB_DIR_IN,
62 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
63 };
64 
65 static struct usb_endpoint_descriptor gser_fs_out_desc = {
66 	.bLength =		USB_DT_ENDPOINT_SIZE,
67 	.bDescriptorType =	USB_DT_ENDPOINT,
68 	.bEndpointAddress =	USB_DIR_OUT,
69 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
70 };
71 
72 static struct usb_descriptor_header *gser_fs_function[] = {
73 	(struct usb_descriptor_header *) &gser_interface_desc,
74 	(struct usb_descriptor_header *) &gser_fs_in_desc,
75 	(struct usb_descriptor_header *) &gser_fs_out_desc,
76 	NULL,
77 };
78 
79 /* high speed support: */
80 
81 static struct usb_endpoint_descriptor gser_hs_in_desc = {
82 	.bLength =		USB_DT_ENDPOINT_SIZE,
83 	.bDescriptorType =	USB_DT_ENDPOINT,
84 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
85 	.wMaxPacketSize =	cpu_to_le16(512),
86 };
87 
88 static struct usb_endpoint_descriptor gser_hs_out_desc = {
89 	.bLength =		USB_DT_ENDPOINT_SIZE,
90 	.bDescriptorType =	USB_DT_ENDPOINT,
91 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
92 	.wMaxPacketSize =	cpu_to_le16(512),
93 };
94 
95 static struct usb_descriptor_header *gser_hs_function[] = {
96 	(struct usb_descriptor_header *) &gser_interface_desc,
97 	(struct usb_descriptor_header *) &gser_hs_in_desc,
98 	(struct usb_descriptor_header *) &gser_hs_out_desc,
99 	NULL,
100 };
101 
102 static struct usb_endpoint_descriptor gser_ss_in_desc = {
103 	.bLength =		USB_DT_ENDPOINT_SIZE,
104 	.bDescriptorType =	USB_DT_ENDPOINT,
105 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
106 	.wMaxPacketSize =	cpu_to_le16(1024),
107 };
108 
109 static struct usb_endpoint_descriptor gser_ss_out_desc = {
110 	.bLength =		USB_DT_ENDPOINT_SIZE,
111 	.bDescriptorType =	USB_DT_ENDPOINT,
112 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
113 	.wMaxPacketSize =	cpu_to_le16(1024),
114 };
115 
116 static struct usb_ss_ep_comp_descriptor gser_ss_bulk_comp_desc = {
117 	.bLength =              sizeof gser_ss_bulk_comp_desc,
118 	.bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
119 };
120 
121 static struct usb_descriptor_header *gser_ss_function[] = {
122 	(struct usb_descriptor_header *) &gser_interface_desc,
123 	(struct usb_descriptor_header *) &gser_ss_in_desc,
124 	(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
125 	(struct usb_descriptor_header *) &gser_ss_out_desc,
126 	(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
127 	NULL,
128 };
129 
130 /* string descriptors: */
131 
132 static struct usb_string gser_string_defs[] = {
133 	[0].s = "Generic Serial",
134 	{  } /* end of list */
135 };
136 
137 static struct usb_gadget_strings gser_string_table = {
138 	.language =		0x0409,	/* en-us */
139 	.strings =		gser_string_defs,
140 };
141 
142 static struct usb_gadget_strings *gser_strings[] = {
143 	&gser_string_table,
144 	NULL,
145 };
146 
147 /*-------------------------------------------------------------------------*/
148 
149 static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
150 {
151 	struct f_gser		*gser = func_to_gser(f);
152 	struct usb_composite_dev *cdev = f->config->cdev;
153 
154 	/* we know alt == 0, so this is an activation or a reset */
155 
156 	if (gser->port.in->driver_data) {
157 		dev_dbg(&cdev->gadget->dev,
158 			"reset generic ttyGS%d\n", gser->port_num);
159 		gserial_disconnect(&gser->port);
160 	}
161 	if (!gser->port.in->desc || !gser->port.out->desc) {
162 		dev_dbg(&cdev->gadget->dev,
163 			"activate generic ttyGS%d\n", gser->port_num);
164 		if (config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
165 		    config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
166 			gser->port.in->desc = NULL;
167 			gser->port.out->desc = NULL;
168 			return -EINVAL;
169 		}
170 	}
171 	gserial_connect(&gser->port, gser->port_num);
172 	return 0;
173 }
174 
175 static void gser_disable(struct usb_function *f)
176 {
177 	struct f_gser	*gser = func_to_gser(f);
178 	struct usb_composite_dev *cdev = f->config->cdev;
179 
180 	dev_dbg(&cdev->gadget->dev,
181 		"generic ttyGS%d deactivated\n", gser->port_num);
182 	gserial_disconnect(&gser->port);
183 }
184 
185 /*-------------------------------------------------------------------------*/
186 
187 /* serial function driver setup/binding */
188 
189 static int gser_bind(struct usb_configuration *c, struct usb_function *f)
190 {
191 	struct usb_composite_dev *cdev = c->cdev;
192 	struct f_gser		*gser = func_to_gser(f);
193 	int			status;
194 	struct usb_ep		*ep;
195 
196 	/* REVISIT might want instance-specific strings to help
197 	 * distinguish instances ...
198 	 */
199 
200 	/* maybe allocate device-global string ID */
201 	if (gser_string_defs[0].id == 0) {
202 		status = usb_string_id(c->cdev);
203 		if (status < 0)
204 			return status;
205 		gser_string_defs[0].id = status;
206 	}
207 
208 	/* allocate instance-specific interface IDs */
209 	status = usb_interface_id(c, f);
210 	if (status < 0)
211 		goto fail;
212 	gser->data_id = status;
213 	gser_interface_desc.bInterfaceNumber = status;
214 
215 	status = -ENODEV;
216 
217 	/* allocate instance-specific endpoints */
218 	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
219 	if (!ep)
220 		goto fail;
221 	gser->port.in = ep;
222 	ep->driver_data = cdev;	/* claim */
223 
224 	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
225 	if (!ep)
226 		goto fail;
227 	gser->port.out = ep;
228 	ep->driver_data = cdev;	/* claim */
229 
230 	/* support all relevant hardware speeds... we expect that when
231 	 * hardware is dual speed, all bulk-capable endpoints work at
232 	 * both speeds
233 	 */
234 	gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
235 	gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
236 
237 	gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
238 	gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
239 
240 	status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function,
241 			gser_ss_function);
242 	if (status)
243 		goto fail;
244 	dev_dbg(&cdev->gadget->dev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
245 		gser->port_num,
246 		gadget_is_superspeed(c->cdev->gadget) ? "super" :
247 		gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
248 		gser->port.in->name, gser->port.out->name);
249 	return 0;
250 
251 fail:
252 	/* we might as well release our claims on endpoints */
253 	if (gser->port.out)
254 		gser->port.out->driver_data = NULL;
255 	if (gser->port.in)
256 		gser->port.in->driver_data = NULL;
257 
258 	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
259 
260 	return status;
261 }
262 
263 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
264 {
265 	return container_of(to_config_group(item), struct f_serial_opts,
266 			    func_inst.group);
267 }
268 
269 CONFIGFS_ATTR_STRUCT(f_serial_opts);
270 static ssize_t f_serial_attr_show(struct config_item *item,
271 				  struct configfs_attribute *attr,
272 				  char *page)
273 {
274 	struct f_serial_opts *opts = to_f_serial_opts(item);
275 	struct f_serial_opts_attribute *f_serial_opts_attr =
276 		container_of(attr, struct f_serial_opts_attribute, attr);
277 	ssize_t ret = 0;
278 
279 	if (f_serial_opts_attr->show)
280 		ret = f_serial_opts_attr->show(opts, page);
281 
282 	return ret;
283 }
284 
285 static void serial_attr_release(struct config_item *item)
286 {
287 	struct f_serial_opts *opts = to_f_serial_opts(item);
288 
289 	usb_put_function_instance(&opts->func_inst);
290 }
291 
292 static struct configfs_item_operations serial_item_ops = {
293 	.release	= serial_attr_release,
294 	.show_attribute = f_serial_attr_show,
295 };
296 
297 static ssize_t f_serial_port_num_show(struct f_serial_opts *opts, char *page)
298 {
299 	return sprintf(page, "%u\n", opts->port_num);
300 }
301 
302 static struct f_serial_opts_attribute f_serial_port_num =
303 	__CONFIGFS_ATTR_RO(port_num, f_serial_port_num_show);
304 
305 static struct configfs_attribute *acm_attrs[] = {
306 	&f_serial_port_num.attr,
307 	NULL,
308 };
309 
310 static struct config_item_type serial_func_type = {
311 	.ct_item_ops	= &serial_item_ops,
312 	.ct_attrs	= acm_attrs,
313 	.ct_owner	= THIS_MODULE,
314 };
315 
316 static void gser_free_inst(struct usb_function_instance *f)
317 {
318 	struct f_serial_opts *opts;
319 
320 	opts = container_of(f, struct f_serial_opts, func_inst);
321 	gserial_free_line(opts->port_num);
322 	kfree(opts);
323 }
324 
325 static struct usb_function_instance *gser_alloc_inst(void)
326 {
327 	struct f_serial_opts *opts;
328 	int ret;
329 
330 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
331 	if (!opts)
332 		return ERR_PTR(-ENOMEM);
333 
334 	opts->func_inst.free_func_inst = gser_free_inst;
335 	ret = gserial_alloc_line(&opts->port_num);
336 	if (ret) {
337 		kfree(opts);
338 		return ERR_PTR(ret);
339 	}
340 	config_group_init_type_name(&opts->func_inst.group, "",
341 				    &serial_func_type);
342 
343 	return &opts->func_inst;
344 }
345 
346 static void gser_free(struct usb_function *f)
347 {
348 	struct f_gser *serial;
349 
350 	serial = func_to_gser(f);
351 	kfree(serial);
352 }
353 
354 static void gser_unbind(struct usb_configuration *c, struct usb_function *f)
355 {
356 	usb_free_all_descriptors(f);
357 }
358 
359 static struct usb_function *gser_alloc(struct usb_function_instance *fi)
360 {
361 	struct f_gser	*gser;
362 	struct f_serial_opts *opts;
363 
364 	/* allocate and initialize one new instance */
365 	gser = kzalloc(sizeof(*gser), GFP_KERNEL);
366 	if (!gser)
367 		return ERR_PTR(-ENOMEM);
368 
369 	opts = container_of(fi, struct f_serial_opts, func_inst);
370 
371 	gser->port_num = opts->port_num;
372 
373 	gser->port.func.name = "gser";
374 	gser->port.func.strings = gser_strings;
375 	gser->port.func.bind = gser_bind;
376 	gser->port.func.unbind = gser_unbind;
377 	gser->port.func.set_alt = gser_set_alt;
378 	gser->port.func.disable = gser_disable;
379 	gser->port.func.free_func = gser_free;
380 
381 	return &gser->port.func;
382 }
383 
384 DECLARE_USB_FUNCTION_INIT(gser, gser_alloc_inst, gser_alloc);
385 MODULE_LICENSE("GPL");
386 MODULE_AUTHOR("Al Borchers");
387 MODULE_AUTHOR("David Brownell");
388