aboutsummaryrefslogtreecommitdiff
path: root/drivers/usb/gadget/epautoconf.c
blob: 8a832488ccdd76cb1c60b577dd4d1e4c6b35c690 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
/*
 * epautoconf.c -- endpoint autoconfiguration for usb gadget drivers
 *
 * Copyright (C) 2004 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/device.h>

#include <linux/ctype.h>
#include <linux/string.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

#include "gadget_chips.h"


/* we must assign addresses for configurable endpoints (like net2280) */
static unsigned epnum;

// #define MANY_ENDPOINTS
#ifdef MANY_ENDPOINTS
/* more than 15 configurable endpoints */
static unsigned in_epnum;
#endif


/*
 * This should work with endpoints from controller drivers sharing the
 * same endpoint naming convention.  By example:
 *
 *	- ep1, ep2, ... address is fixed, not direction or type
 *	- ep1in, ep2out, ... address and direction are fixed, not type
 *	- ep1-bulk, ep2-bulk, ... address and type are fixed, not direction
 *	- ep1in-bulk, ep2out-iso, ... all three are fixed
 *	- ep-* ... no functionality restrictions
 *
 * Type suffixes are "-bulk", "-iso", or "-int".  Numbers are decimal.
 * Less common restrictions are implied by gadget_is_*().
 *
 * NOTE:  each endpoint is unidirectional, as specified by its USB
 * descriptor; and isn't specific to a configuration or altsetting.
 */
static int
ep_matches (
	struct usb_gadget		*gadget,
	struct usb_ep			*ep,
	struct usb_endpoint_descriptor	*desc
)
{
	u8		type;
	const char	*tmp;
	u16		max;

	/* endpoint already claimed? */
	if (NULL != ep->driver_data)
		return 0;

	/* only support ep0 for portable CONTROL traffic */
	type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
	if (USB_ENDPOINT_XFER_CONTROL == type)
		return 0;

	/* some other naming convention */
	if ('e' != ep->name[0])
		return 0;

	/* type-restriction:  "-iso", "-bulk", or "-int".
	 * direction-restriction:  "in", "out".
	 */
	if ('-' != ep->name[2]) {
		tmp = strrchr (ep->name, '-');
		if (tmp) {
			switch (type) {
			case USB_ENDPOINT_XFER_INT:
				/* bulk endpoints handle interrupt transfers,
				 * except the toggle-quirky iso-synch kind
				 */
				if ('s' == tmp[2])	// == "-iso"
					return 0;
				/* for now, avoid PXA "interrupt-in";
				 * it's documented as never using DATA1.
				 */
				if (gadget_is_pxa (gadget)
						&& 'i' == tmp [1])
					return 0;
				break;
			case USB_ENDPOINT_XFER_BULK:
				if ('b' != tmp[1])	// != "-bulk"
					return 0;
				break;
			case USB_ENDPOINT_XFER_ISOC:
				if ('s' != tmp[2])	// != "-iso"
					return 0;
			}
		} else {
			tmp = ep->name + strlen (ep->name);
		}

		/* direction-restriction:  "..in-..", "out-.." */
		tmp--;
		if (!isdigit (*tmp)) {
			if (desc->bEndpointAddress & USB_DIR_IN) {
				if ('n' != *tmp)
					return 0;
			} else {
				if ('t' != *tmp)
					return 0;
			}
		}
	}

	/* endpoint maxpacket size is an input parameter, except for bulk
	 * where it's an output parameter representing the full speed limit.
	 * the usb spec fixes high speed bulk maxpacket at 512 bytes.
	 */
	max = 0x7ff & le16_to_cpu(desc->wMaxPacketSize);
	switch (type) {
	case USB_ENDPOINT_XFER_INT:
		/* INT:  limit 64 bytes full speed, 1024 high speed */
		if (!gadget->is_dualspeed && max > 64)
			return 0;
		/* FALLTHROUGH */

	case USB_ENDPOINT_XFER_ISOC:
		/* ISO:  limit 1023 bytes full speed, 1024 high speed */
		if (ep->maxpacket < max)
			return 0;
		if (!gadget->is_dualspeed && max > 1023)
			return 0;

		/* BOTH:  "high bandwidth" works only at high speed */
		if ((desc->wMaxPacketSize & cpu_to_le16(3<<11))) {
			if (!gadget->is_dualspeed)
				return 0;
			/* configure your hardware with enough buffering!! */
		}
		break;
	}

	/* MATCH!! */

	/* report address */
	desc->bEndpointAddress &= USB_DIR_IN;
	if (isdigit (ep->name [2])) {
		u8	num = simple_strtoul (&ep->name [2], NULL, 10);
		desc->bEndpointAddress |= num;
#ifdef	MANY_ENDPOINTS
	} else if (desc->bEndpointAddress & USB_DIR_IN) {
		if (++in_epnum > 15)
			return 0;
		desc->bEndpointAddress = USB_DIR_IN | in_epnum;
#endif
	} else {
		if (++epnum > 15)
			return 0;
		desc->bEndpointAddress |= epnum;
	}

	/* report (variable) full speed bulk maxpacket */
	if (USB_ENDPOINT_XFER_BULK == type) {
		int size = ep->maxpacket;

		/* min() doesn't work on bitfields with gcc-3.5 */
		if (size > 64)
			size = 64;
		desc->wMaxPacketSize = cpu_to_le16(size);
	}
	return 1;
}

static struct usb_ep *
find_ep (struct usb_gadget *gadget, const char *name)
{
	struct usb_ep	*ep;

	list_for_each_entry (ep, &gadget->ep_list, ep_list) {
		if (0 == strcmp (ep->name, name))
			return ep;
	}
	return NULL;
}

/**
 * usb_ep_autoconfig - choose an endpoint matching the descriptor
 * @gadget: The device to which the endpoint must belong.
 * @desc: Endpoint descriptor, with endpoint direction and transfer mode
 *	initialized.  For periodic transfers, the maximum packet
 *	size must also be initialized.  This is modified on success.
 *
 * By choosing an endpoint to use with the specified descriptor, this
 * routine simplifies writing gadget drivers that work with multiple
 * USB device controllers.  The endpoint would be passed later to
 * usb_ep_enable(), along with some descriptor.
 *
 * That second descriptor won't always be the same as the first one.
 * For example, isochronous endpoints can be autoconfigured for high
 * bandwidth, and then used in several lower bandwidth altsettings.
 * Also, high and full speed descriptors will be different.
 *
 * Be sure to examine and test the results of autoconfiguration on your
 * hardware.  This code may not make the best choices about how to use the
 * USB controller, and it can't know all the restrictions that may apply.
 * Some combinations of driver and hardware won't be able to autoconfigure.
 *
 * On success, this returns an un-claimed usb_ep, and modifies the endpoint
 * descriptor bEndpointAddress.  For bulk endpoints, the wMaxPacket value
 * is initialized as if the endpoint were used at full speed.  To prevent
 * the endpoint from being returned by a later autoconfig call, claim it
 * by assigning ep->driver_data to some non-null value.
 *
 * On failure, this returns a null endpoint descriptor.
 */
struct usb_ep *usb_ep_autoconfig (
	struct usb_gadget		*gadget,
	struct usb_endpoint_descriptor	*desc
)
{
	struct usb_ep	*ep;
	u8		type;

	type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;

	/* First, apply chip-specific "best usage" knowledge.
	 * This might make a good usb_gadget_ops hook ...
	 */
	if (gadget_is_net2280 (gadget) && type == USB_ENDPOINT_XFER_INT) {
		/* ep-e, ep-f are PIO with only 64 byte fifos */
		ep = find_ep (gadget, "ep-e");
		if (ep && ep_matches (gadget, ep, desc))
			return ep;
		ep = find_ep (gadget, "ep-f");
		if (ep && ep_matches (gadget, ep, desc))
			return ep;

	} else if (gadget_is_goku (gadget)) {
		if (USB_ENDPOINT_XFER_INT == type) {
			/* single buffering is enough */
			ep = find_ep (gadget, "ep3-bulk");
			if (ep && ep_matches (gadget, ep, desc))
				return ep;
		} else if (USB_ENDPOINT_XFER_BULK == type
				&& (USB_DIR_IN & desc->bEndpointAddress)) {
			/* DMA may be available */
			ep = find_ep (gadget, "ep2-bulk");
			if (ep && ep_matches (gadget, ep, desc))
				return ep;
		}

#ifdef CONFIG_BLACKFIN
	} else if (gadget_is_musbhdrc(gadget)) {
		if ((USB_ENDPOINT_XFER_BULK == type) ||
		    (USB_ENDPOINT_XFER_ISOC == type)) {
			if (USB_DIR_IN & desc->bEndpointAddress)
				ep = find_ep (gadget, "ep5in");
			else
				ep = find_ep (gadget, "ep6out");
		} else if (USB_ENDPOINT_XFER_INT == type) {
			if (USB_DIR_IN & desc->bEndpointAddress)
				ep = find_ep(gadget, "ep1in");
			else
				ep = find_ep(gadget, "ep2out");
		} else
			ep = NULL;
		if (ep && ep_matches (gadget, ep, desc))
			return ep;
#endif
	}

	/* Second, look at endpoints until an unclaimed one looks usable */
	list_for_each_entry (ep, &gadget->ep_list, ep_list) {
		if (ep_matches (gadget, ep, desc))
			return ep;
	}

	/* Fail */
	return NULL;
}

/**
 * usb_ep_autoconfig_reset - reset endpoint autoconfig state
 * @gadget: device for which autoconfig state will be reset
 *
 * Use this for devices where one configuration may need to assign
 * endpoint resources very differently from the next one.  It clears
 * state such as ep->driver_data and the record of assigned endpoints
 * used by usb_ep_autoconfig().
 */
void usb_ep_autoconfig_reset (struct usb_gadget *gadget)
{
	struct usb_ep	*ep;

	list_for_each_entry (ep, &gadget->ep_list, ep_list) {
		ep->driver_data = NULL;
	}
#ifdef	MANY_ENDPOINTS
	in_epnum = 0;
#endif
	epnum = 0;
}