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
30struct f_gser {
31	struct gserial			port;
32	u8				data_id;
33	u8				port_num;
34};
35
36static 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
45static 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
58static 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
65static 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
72static 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
81static 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
88static 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
95static 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
102static 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
109static 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
116static 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
121static 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
132static struct usb_string gser_string_defs[] = {
133	[0].s = "Generic Serial",
134	{  } /* end of list */
135};
136
137static struct usb_gadget_strings gser_string_table = {
138	.language =		0x0409,	/* en-us */
139	.strings =		gser_string_defs,
140};
141
142static struct usb_gadget_strings *gser_strings[] = {
143	&gser_string_table,
144	NULL,
145};
146
147/*-------------------------------------------------------------------------*/
148
149static 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->enabled) {
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
175static 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
189static 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
223	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
224	if (!ep)
225		goto fail;
226	gser->port.out = ep;
227
228	/* support all relevant hardware speeds... we expect that when
229	 * hardware is dual speed, all bulk-capable endpoints work at
230	 * both speeds
231	 */
232	gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
233	gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
234
235	gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
236	gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;
237
238	status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function,
239			gser_ss_function);
240	if (status)
241		goto fail;
242	dev_dbg(&cdev->gadget->dev, "generic ttyGS%d: %s speed IN/%s OUT/%s\n",
243		gser->port_num,
244		gadget_is_superspeed(c->cdev->gadget) ? "super" :
245		gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
246		gser->port.in->name, gser->port.out->name);
247	return 0;
248
249fail:
250	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
251
252	return status;
253}
254
255static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
256{
257	return container_of(to_config_group(item), struct f_serial_opts,
258			    func_inst.group);
259}
260
261static void serial_attr_release(struct config_item *item)
262{
263	struct f_serial_opts *opts = to_f_serial_opts(item);
264
265	usb_put_function_instance(&opts->func_inst);
266}
267
268static struct configfs_item_operations serial_item_ops = {
269	.release	= serial_attr_release,
270};
271
272static ssize_t f_serial_port_num_show(struct config_item *item, char *page)
273{
274	return sprintf(page, "%u\n", to_f_serial_opts(item)->port_num);
275}
276
277CONFIGFS_ATTR_RO(f_serial_, port_num);
278
279static struct configfs_attribute *acm_attrs[] = {
280	&f_serial_attr_port_num,
281	NULL,
282};
283
284static struct config_item_type serial_func_type = {
285	.ct_item_ops	= &serial_item_ops,
286	.ct_attrs	= acm_attrs,
287	.ct_owner	= THIS_MODULE,
288};
289
290static void gser_free_inst(struct usb_function_instance *f)
291{
292	struct f_serial_opts *opts;
293
294	opts = container_of(f, struct f_serial_opts, func_inst);
295	gserial_free_line(opts->port_num);
296	kfree(opts);
297}
298
299static struct usb_function_instance *gser_alloc_inst(void)
300{
301	struct f_serial_opts *opts;
302	int ret;
303
304	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
305	if (!opts)
306		return ERR_PTR(-ENOMEM);
307
308	opts->func_inst.free_func_inst = gser_free_inst;
309	ret = gserial_alloc_line(&opts->port_num);
310	if (ret) {
311		kfree(opts);
312		return ERR_PTR(ret);
313	}
314	config_group_init_type_name(&opts->func_inst.group, "",
315				    &serial_func_type);
316
317	return &opts->func_inst;
318}
319
320static void gser_free(struct usb_function *f)
321{
322	struct f_gser *serial;
323
324	serial = func_to_gser(f);
325	kfree(serial);
326}
327
328static void gser_unbind(struct usb_configuration *c, struct usb_function *f)
329{
330	usb_free_all_descriptors(f);
331}
332
333static struct usb_function *gser_alloc(struct usb_function_instance *fi)
334{
335	struct f_gser	*gser;
336	struct f_serial_opts *opts;
337
338	/* allocate and initialize one new instance */
339	gser = kzalloc(sizeof(*gser), GFP_KERNEL);
340	if (!gser)
341		return ERR_PTR(-ENOMEM);
342
343	opts = container_of(fi, struct f_serial_opts, func_inst);
344
345	gser->port_num = opts->port_num;
346
347	gser->port.func.name = "gser";
348	gser->port.func.strings = gser_strings;
349	gser->port.func.bind = gser_bind;
350	gser->port.func.unbind = gser_unbind;
351	gser->port.func.set_alt = gser_set_alt;
352	gser->port.func.disable = gser_disable;
353	gser->port.func.free_func = gser_free;
354
355	return &gser->port.func;
356}
357
358DECLARE_USB_FUNCTION_INIT(gser, gser_alloc_inst, gser_alloc);
359MODULE_LICENSE("GPL");
360MODULE_AUTHOR("Al Borchers");
361MODULE_AUTHOR("David Brownell");
362