1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * f_serial.c - generic USB serial function 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/slab.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/device.h>
14 
15 #include "u_serial.h"
16 
17 
18 /*
19  * This function packages a simple "generic serial" port with no real
20  * control mechanisms, just raw data transfer over two bulk endpoints.
21  *
22  * Because it's not standardized, this isn't as interoperable as the
23  * CDC ACM driver.  However, for many purposes it's just as functional
24  * if you can arrange appropriate host side drivers.
25  */
26 
27 struct f_gser {
28 	struct gserial			port;
29 	u8				data_id;
30 	u8				port_num;
31 };
32 
33 static inline struct f_gser *func_to_gser(struct usb_function *f)
34 {
35 	return container_of(f, struct f_gser, port.func);
36 }
37 
38 /*-------------------------------------------------------------------------*/
39 
40 /* interface descriptor: */
41 
42 static struct usb_interface_descriptor gser_interface_desc = {
43 	.bLength =		USB_DT_INTERFACE_SIZE,
44 	.bDescriptorType =	USB_DT_INTERFACE,
45 	/* .bInterfaceNumber = DYNAMIC */
46 	.bNumEndpoints =	2,
47 	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
48 	.bInterfaceSubClass =	0,
49 	.bInterfaceProtocol =	0,
50 	/* .iInterface = DYNAMIC */
51 };
52 
53 /* full speed support: */
54 
55 static struct usb_endpoint_descriptor gser_fs_in_desc = {
56 	.bLength =		USB_DT_ENDPOINT_SIZE,
57 	.bDescriptorType =	USB_DT_ENDPOINT,
58 	.bEndpointAddress =	USB_DIR_IN,
59 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
60 };
61 
62 static struct usb_endpoint_descriptor gser_fs_out_desc = {
63 	.bLength =		USB_DT_ENDPOINT_SIZE,
64 	.bDescriptorType =	USB_DT_ENDPOINT,
65 	.bEndpointAddress =	USB_DIR_OUT,
66 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
67 };
68 
69 static struct usb_descriptor_header *gser_fs_function[] = {
70 	(struct usb_descriptor_header *) &gser_interface_desc,
71 	(struct usb_descriptor_header *) &gser_fs_in_desc,
72 	(struct usb_descriptor_header *) &gser_fs_out_desc,
73 	NULL,
74 };
75 
76 /* high speed support: */
77 
78 static struct usb_endpoint_descriptor gser_hs_in_desc = {
79 	.bLength =		USB_DT_ENDPOINT_SIZE,
80 	.bDescriptorType =	USB_DT_ENDPOINT,
81 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
82 	.wMaxPacketSize =	cpu_to_le16(512),
83 };
84 
85 static struct usb_endpoint_descriptor gser_hs_out_desc = {
86 	.bLength =		USB_DT_ENDPOINT_SIZE,
87 	.bDescriptorType =	USB_DT_ENDPOINT,
88 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
89 	.wMaxPacketSize =	cpu_to_le16(512),
90 };
91 
92 static struct usb_descriptor_header *gser_hs_function[] = {
93 	(struct usb_descriptor_header *) &gser_interface_desc,
94 	(struct usb_descriptor_header *) &gser_hs_in_desc,
95 	(struct usb_descriptor_header *) &gser_hs_out_desc,
96 	NULL,
97 };
98 
99 static struct usb_endpoint_descriptor gser_ss_in_desc = {
100 	.bLength =		USB_DT_ENDPOINT_SIZE,
101 	.bDescriptorType =	USB_DT_ENDPOINT,
102 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
103 	.wMaxPacketSize =	cpu_to_le16(1024),
104 };
105 
106 static struct usb_endpoint_descriptor gser_ss_out_desc = {
107 	.bLength =		USB_DT_ENDPOINT_SIZE,
108 	.bDescriptorType =	USB_DT_ENDPOINT,
109 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
110 	.wMaxPacketSize =	cpu_to_le16(1024),
111 };
112 
113 static struct usb_ss_ep_comp_descriptor gser_ss_bulk_comp_desc = {
114 	.bLength =              sizeof gser_ss_bulk_comp_desc,
115 	.bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
116 };
117 
118 static struct usb_descriptor_header *gser_ss_function[] = {
119 	(struct usb_descriptor_header *) &gser_interface_desc,
120 	(struct usb_descriptor_header *) &gser_ss_in_desc,
121 	(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
122 	(struct usb_descriptor_header *) &gser_ss_out_desc,
123 	(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
124 	NULL,
125 };
126 
127 /* string descriptors: */
128 
129 static struct usb_string gser_string_defs[] = {
130 	[0].s = "Generic Serial",
131 	{  } /* end of list */
132 };
133 
134 static struct usb_gadget_strings gser_string_table = {
135 	.language =		0x0409,	/* en-us */
136 	.strings =		gser_string_defs,
137 };
138 
139 static struct usb_gadget_strings *gser_strings[] = {
140 	&gser_string_table,
141 	NULL,
142 };
143 
144 /*-------------------------------------------------------------------------*/
145 
146 static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
147 {
148 	struct f_gser		*gser = func_to_gser(f);
149 	struct usb_composite_dev *cdev = f->config->cdev;
150 
151 	/* we know alt == 0, so this is an activation or a reset */
152 
153 	if (gser->port.in->enabled) {
154 		dev_dbg(&cdev->gadget->dev,
155 			"reset generic ttyGS%d\n", gser->port_num);
156 		gserial_disconnect(&gser->port);
157 	}
158 	if (!gser->port.in->desc || !gser->port.out->desc) {
159 		dev_dbg(&cdev->gadget->dev,
160 			"activate generic ttyGS%d\n", gser->port_num);
161 		if (config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
162 		    config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
163 			gser->port.in->desc = NULL;
164 			gser->port.out->desc = NULL;
165 			return -EINVAL;
166 		}
167 	}
168 	gserial_connect(&gser->port, gser->port_num);
169 	return 0;
170 }
171 
172 static void gser_disable(struct usb_function *f)
173 {
174 	struct f_gser	*gser = func_to_gser(f);
175 	struct usb_composite_dev *cdev = f->config->cdev;
176 
177 	dev_dbg(&cdev->gadget->dev,
178 		"generic ttyGS%d deactivated\n", gser->port_num);
179 	gserial_disconnect(&gser->port);
180 }
181 
182 /*-------------------------------------------------------------------------*/
183 
184 /* serial function driver setup/binding */
185 
186 static int gser_bind(struct usb_configuration *c, struct usb_function *f)
187 {
188 	struct usb_composite_dev *cdev = c->cdev;
189 	struct f_gser		*gser = func_to_gser(f);
190 	int			status;
191 	struct usb_ep		*ep;
192 
193 	/* REVISIT might want instance-specific strings to help
194 	 * distinguish instances ...
195 	 */
196 
197 	/* maybe allocate device-global string ID */
198 	if (gser_string_defs[0].id == 0) {
199 		status = usb_string_id(c->cdev);
200 		if (status < 0)
201 			return status;
202 		gser_string_defs[0].id = status;
203 	}
204 
205 	/* allocate instance-specific interface IDs */
206 	status = usb_interface_id(c, f);
207 	if (status < 0)
208 		goto fail;
209 	gser->data_id = status;
210 	gser_interface_desc.bInterfaceNumber = status;
211 
212 	status = -ENODEV;
213 
214 	/* allocate instance-specific endpoints */
215 	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
216 	if (!ep)
217 		goto fail;
218 	gser->port.in = ep;
219 
220 	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
221 	if (!ep)
222 		goto fail;
223 	gser->port.out = ep;
224 
225 	/* support all relevant hardware speeds... we expect that when
226 	 * hardware is dual speed, all bulk-capable endpoints work at
227 	 * both speeds
228 	 */
229 	gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
230 	gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
231 
232 	gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
233 	gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
234 
235 	status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function,
236 			gser_ss_function, gser_ss_function);
237 	if (status)
238 		goto fail;
239 	dev_dbg(&cdev->gadget->dev, "generic ttyGS%d: IN/%s OUT/%s\n",
240 		gser->port_num,
241 		gser->port.in->name, gser->port.out->name);
242 	return 0;
243 
244 fail:
245 	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
246 
247 	return status;
248 }
249 
250 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
251 {
252 	return container_of(to_config_group(item), struct f_serial_opts,
253 			    func_inst.group);
254 }
255 
256 static void serial_attr_release(struct config_item *item)
257 {
258 	struct f_serial_opts *opts = to_f_serial_opts(item);
259 
260 	usb_put_function_instance(&opts->func_inst);
261 }
262 
263 static struct configfs_item_operations serial_item_ops = {
264 	.release	= serial_attr_release,
265 };
266 
267 #ifdef CONFIG_U_SERIAL_CONSOLE
268 
269 static ssize_t f_serial_console_store(struct config_item *item,
270 		const char *page, size_t count)
271 {
272 	return gserial_set_console(to_f_serial_opts(item)->port_num,
273 				   page, count);
274 }
275 
276 static ssize_t f_serial_console_show(struct config_item *item, char *page)
277 {
278 	return gserial_get_console(to_f_serial_opts(item)->port_num, page);
279 }
280 
281 CONFIGFS_ATTR(f_serial_, console);
282 
283 #endif /* CONFIG_U_SERIAL_CONSOLE */
284 
285 static ssize_t f_serial_port_num_show(struct config_item *item, char *page)
286 {
287 	return sprintf(page, "%u\n", to_f_serial_opts(item)->port_num);
288 }
289 
290 CONFIGFS_ATTR_RO(f_serial_, port_num);
291 
292 static struct configfs_attribute *acm_attrs[] = {
293 #ifdef CONFIG_U_SERIAL_CONSOLE
294 	&f_serial_attr_console,
295 #endif
296 	&f_serial_attr_port_num,
297 	NULL,
298 };
299 
300 static const struct config_item_type serial_func_type = {
301 	.ct_item_ops	= &serial_item_ops,
302 	.ct_attrs	= acm_attrs,
303 	.ct_owner	= THIS_MODULE,
304 };
305 
306 static void gser_free_inst(struct usb_function_instance *f)
307 {
308 	struct f_serial_opts *opts;
309 
310 	opts = container_of(f, struct f_serial_opts, func_inst);
311 	gserial_free_line(opts->port_num);
312 	kfree(opts);
313 }
314 
315 static struct usb_function_instance *gser_alloc_inst(void)
316 {
317 	struct f_serial_opts *opts;
318 	int ret;
319 
320 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
321 	if (!opts)
322 		return ERR_PTR(-ENOMEM);
323 
324 	opts->func_inst.free_func_inst = gser_free_inst;
325 	ret = gserial_alloc_line(&opts->port_num);
326 	if (ret) {
327 		kfree(opts);
328 		return ERR_PTR(ret);
329 	}
330 	config_group_init_type_name(&opts->func_inst.group, "",
331 				    &serial_func_type);
332 
333 	return &opts->func_inst;
334 }
335 
336 static void gser_free(struct usb_function *f)
337 {
338 	struct f_gser *serial;
339 
340 	serial = func_to_gser(f);
341 	kfree(serial);
342 }
343 
344 static void gser_unbind(struct usb_configuration *c, struct usb_function *f)
345 {
346 	struct f_gser	*gser = func_to_gser(f);
347 
348 	/* Ensure port is disconnected before unbinding */
349 	gserial_disconnect(&gser->port);
350 	usb_free_all_descriptors(f);
351 }
352 
353 static void gser_resume(struct usb_function *f)
354 {
355 	struct f_gser *gser = func_to_gser(f);
356 
357 	gserial_resume(&gser->port);
358 }
359 
360 static void gser_suspend(struct usb_function *f)
361 {
362 	struct f_gser *gser = func_to_gser(f);
363 
364 	gserial_suspend(&gser->port);
365 }
366 
367 static struct usb_function *gser_alloc(struct usb_function_instance *fi)
368 {
369 	struct f_gser	*gser;
370 	struct f_serial_opts *opts;
371 
372 	/* allocate and initialize one new instance */
373 	gser = kzalloc(sizeof(*gser), GFP_KERNEL);
374 	if (!gser)
375 		return ERR_PTR(-ENOMEM);
376 
377 	opts = container_of(fi, struct f_serial_opts, func_inst);
378 
379 	gser->port_num = opts->port_num;
380 
381 	gser->port.func.name = "gser";
382 	gser->port.func.strings = gser_strings;
383 	gser->port.func.bind = gser_bind;
384 	gser->port.func.unbind = gser_unbind;
385 	gser->port.func.set_alt = gser_set_alt;
386 	gser->port.func.disable = gser_disable;
387 	gser->port.func.free_func = gser_free;
388 	gser->port.func.resume = gser_resume;
389 	gser->port.func.suspend = gser_suspend;
390 
391 	return &gser->port.func;
392 }
393 
394 DECLARE_USB_FUNCTION_INIT(gser, gser_alloc_inst, gser_alloc);
395 MODULE_LICENSE("GPL");
396 MODULE_AUTHOR("Al Borchers");
397 MODULE_AUTHOR("David Brownell");
398