xref: /openbmc/linux/drivers/usb/gadget/epautoconf.c (revision e23feb16)
1 /*
2  * epautoconf.c -- endpoint autoconfiguration for usb gadget drivers
3  *
4  * Copyright (C) 2004 David Brownell
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/types.h>
16 #include <linux/device.h>
17 
18 #include <linux/ctype.h>
19 #include <linux/string.h>
20 
21 #include <linux/usb/ch9.h>
22 #include <linux/usb/gadget.h>
23 
24 #include "gadget_chips.h"
25 
26 /*
27  * This should work with endpoints from controller drivers sharing the
28  * same endpoint naming convention.  By example:
29  *
30  *	- ep1, ep2, ... address is fixed, not direction or type
31  *	- ep1in, ep2out, ... address and direction are fixed, not type
32  *	- ep1-bulk, ep2-bulk, ... address and type are fixed, not direction
33  *	- ep1in-bulk, ep2out-iso, ... all three are fixed
34  *	- ep-* ... no functionality restrictions
35  *
36  * Type suffixes are "-bulk", "-iso", or "-int".  Numbers are decimal.
37  * Less common restrictions are implied by gadget_is_*().
38  *
39  * NOTE:  each endpoint is unidirectional, as specified by its USB
40  * descriptor; and isn't specific to a configuration or altsetting.
41  */
42 static int
43 ep_matches (
44 	struct usb_gadget		*gadget,
45 	struct usb_ep			*ep,
46 	struct usb_endpoint_descriptor	*desc,
47 	struct usb_ss_ep_comp_descriptor *ep_comp
48 )
49 {
50 	u8		type;
51 	const char	*tmp;
52 	u16		max;
53 
54 	int		num_req_streams = 0;
55 
56 	/* endpoint already claimed? */
57 	if (NULL != ep->driver_data)
58 		return 0;
59 
60 	/* only support ep0 for portable CONTROL traffic */
61 	type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
62 	if (USB_ENDPOINT_XFER_CONTROL == type)
63 		return 0;
64 
65 	/* some other naming convention */
66 	if ('e' != ep->name[0])
67 		return 0;
68 
69 	/* type-restriction:  "-iso", "-bulk", or "-int".
70 	 * direction-restriction:  "in", "out".
71 	 */
72 	if ('-' != ep->name[2]) {
73 		tmp = strrchr (ep->name, '-');
74 		if (tmp) {
75 			switch (type) {
76 			case USB_ENDPOINT_XFER_INT:
77 				/* bulk endpoints handle interrupt transfers,
78 				 * except the toggle-quirky iso-synch kind
79 				 */
80 				if ('s' == tmp[2])	// == "-iso"
81 					return 0;
82 				/* for now, avoid PXA "interrupt-in";
83 				 * it's documented as never using DATA1.
84 				 */
85 				if (gadget_is_pxa (gadget)
86 						&& 'i' == tmp [1])
87 					return 0;
88 				break;
89 			case USB_ENDPOINT_XFER_BULK:
90 				if ('b' != tmp[1])	// != "-bulk"
91 					return 0;
92 				break;
93 			case USB_ENDPOINT_XFER_ISOC:
94 				if ('s' != tmp[2])	// != "-iso"
95 					return 0;
96 			}
97 		} else {
98 			tmp = ep->name + strlen (ep->name);
99 		}
100 
101 		/* direction-restriction:  "..in-..", "out-.." */
102 		tmp--;
103 		if (!isdigit (*tmp)) {
104 			if (desc->bEndpointAddress & USB_DIR_IN) {
105 				if ('n' != *tmp)
106 					return 0;
107 			} else {
108 				if ('t' != *tmp)
109 					return 0;
110 			}
111 		}
112 	}
113 
114 	/*
115 	 * Get the number of required streams from the EP companion
116 	 * descriptor and see if the EP matches it
117 	 */
118 	if (usb_endpoint_xfer_bulk(desc)) {
119 		if (ep_comp && gadget->max_speed >= USB_SPEED_SUPER) {
120 			num_req_streams = ep_comp->bmAttributes & 0x1f;
121 			if (num_req_streams > ep->max_streams)
122 				return 0;
123 		}
124 
125 	}
126 
127 	/*
128 	 * If the protocol driver hasn't yet decided on wMaxPacketSize
129 	 * and wants to know the maximum possible, provide the info.
130 	 */
131 	if (desc->wMaxPacketSize == 0)
132 		desc->wMaxPacketSize = cpu_to_le16(ep->maxpacket);
133 
134 	/* endpoint maxpacket size is an input parameter, except for bulk
135 	 * where it's an output parameter representing the full speed limit.
136 	 * the usb spec fixes high speed bulk maxpacket at 512 bytes.
137 	 */
138 	max = 0x7ff & usb_endpoint_maxp(desc);
139 	switch (type) {
140 	case USB_ENDPOINT_XFER_INT:
141 		/* INT:  limit 64 bytes full speed, 1024 high/super speed */
142 		if (!gadget_is_dualspeed(gadget) && max > 64)
143 			return 0;
144 		/* FALLTHROUGH */
145 
146 	case USB_ENDPOINT_XFER_ISOC:
147 		/* ISO:  limit 1023 bytes full speed, 1024 high/super speed */
148 		if (ep->maxpacket < max)
149 			return 0;
150 		if (!gadget_is_dualspeed(gadget) && max > 1023)
151 			return 0;
152 
153 		/* BOTH:  "high bandwidth" works only at high speed */
154 		if ((desc->wMaxPacketSize & cpu_to_le16(3<<11))) {
155 			if (!gadget_is_dualspeed(gadget))
156 				return 0;
157 			/* configure your hardware with enough buffering!! */
158 		}
159 		break;
160 	}
161 
162 	/* MATCH!! */
163 
164 	/* report address */
165 	desc->bEndpointAddress &= USB_DIR_IN;
166 	if (isdigit (ep->name [2])) {
167 		u8	num = simple_strtoul (&ep->name [2], NULL, 10);
168 		desc->bEndpointAddress |= num;
169 	} else if (desc->bEndpointAddress & USB_DIR_IN) {
170 		if (++gadget->in_epnum > 15)
171 			return 0;
172 		desc->bEndpointAddress = USB_DIR_IN | gadget->in_epnum;
173 	} else {
174 		if (++gadget->out_epnum > 15)
175 			return 0;
176 		desc->bEndpointAddress |= gadget->out_epnum;
177 	}
178 
179 	/* report (variable) full speed bulk maxpacket */
180 	if ((USB_ENDPOINT_XFER_BULK == type) && !ep_comp) {
181 		int size = ep->maxpacket;
182 
183 		/* min() doesn't work on bitfields with gcc-3.5 */
184 		if (size > 64)
185 			size = 64;
186 		desc->wMaxPacketSize = cpu_to_le16(size);
187 	}
188 	ep->address = desc->bEndpointAddress;
189 	return 1;
190 }
191 
192 static struct usb_ep *
193 find_ep (struct usb_gadget *gadget, const char *name)
194 {
195 	struct usb_ep	*ep;
196 
197 	list_for_each_entry (ep, &gadget->ep_list, ep_list) {
198 		if (0 == strcmp (ep->name, name))
199 			return ep;
200 	}
201 	return NULL;
202 }
203 
204 /**
205  * usb_ep_autoconfig_ss() - choose an endpoint matching the ep
206  * descriptor and ep companion descriptor
207  * @gadget: The device to which the endpoint must belong.
208  * @desc: Endpoint descriptor, with endpoint direction and transfer mode
209  *    initialized.  For periodic transfers, the maximum packet
210  *    size must also be initialized.  This is modified on
211  *    success.
212  * @ep_comp: Endpoint companion descriptor, with the required
213  *    number of streams. Will be modified when the chosen EP
214  *    supports a different number of streams.
215  *
216  * This routine replaces the usb_ep_autoconfig when needed
217  * superspeed enhancments. If such enhancemnets are required,
218  * the FD should call usb_ep_autoconfig_ss directly and provide
219  * the additional ep_comp parameter.
220  *
221  * By choosing an endpoint to use with the specified descriptor,
222  * this routine simplifies writing gadget drivers that work with
223  * multiple USB device controllers.  The endpoint would be
224  * passed later to usb_ep_enable(), along with some descriptor.
225  *
226  * That second descriptor won't always be the same as the first one.
227  * For example, isochronous endpoints can be autoconfigured for high
228  * bandwidth, and then used in several lower bandwidth altsettings.
229  * Also, high and full speed descriptors will be different.
230  *
231  * Be sure to examine and test the results of autoconfiguration
232  * on your hardware.  This code may not make the best choices
233  * about how to use the USB controller, and it can't know all
234  * the restrictions that may apply. Some combinations of driver
235  * and hardware won't be able to autoconfigure.
236  *
237  * On success, this returns an un-claimed usb_ep, and modifies the endpoint
238  * descriptor bEndpointAddress.  For bulk endpoints, the wMaxPacket value
239  * is initialized as if the endpoint were used at full speed and
240  * the bmAttribute field in the ep companion descriptor is
241  * updated with the assigned number of streams if it is
242  * different from the original value. To prevent the endpoint
243  * from being returned by a later autoconfig call, claim it by
244  * assigning ep->driver_data to some non-null value.
245  *
246  * On failure, this returns a null endpoint descriptor.
247  */
248 struct usb_ep *usb_ep_autoconfig_ss(
249 	struct usb_gadget		*gadget,
250 	struct usb_endpoint_descriptor	*desc,
251 	struct usb_ss_ep_comp_descriptor *ep_comp
252 )
253 {
254 	struct usb_ep	*ep;
255 	u8		type;
256 
257 	type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
258 
259 	/* First, apply chip-specific "best usage" knowledge.
260 	 * This might make a good usb_gadget_ops hook ...
261 	 */
262 	if (gadget_is_net2280 (gadget) && type == USB_ENDPOINT_XFER_INT) {
263 		/* ep-e, ep-f are PIO with only 64 byte fifos */
264 		ep = find_ep (gadget, "ep-e");
265 		if (ep && ep_matches(gadget, ep, desc, ep_comp))
266 			goto found_ep;
267 		ep = find_ep (gadget, "ep-f");
268 		if (ep && ep_matches(gadget, ep, desc, ep_comp))
269 			goto found_ep;
270 
271 	} else if (gadget_is_goku (gadget)) {
272 		if (USB_ENDPOINT_XFER_INT == type) {
273 			/* single buffering is enough */
274 			ep = find_ep(gadget, "ep3-bulk");
275 			if (ep && ep_matches(gadget, ep, desc, ep_comp))
276 				goto found_ep;
277 		} else if (USB_ENDPOINT_XFER_BULK == type
278 				&& (USB_DIR_IN & desc->bEndpointAddress)) {
279 			/* DMA may be available */
280 			ep = find_ep(gadget, "ep2-bulk");
281 			if (ep && ep_matches(gadget, ep, desc,
282 					      ep_comp))
283 				goto found_ep;
284 		}
285 
286 #ifdef CONFIG_BLACKFIN
287 	} else if (gadget_is_musbhdrc(gadget)) {
288 		if ((USB_ENDPOINT_XFER_BULK == type) ||
289 		    (USB_ENDPOINT_XFER_ISOC == type)) {
290 			if (USB_DIR_IN & desc->bEndpointAddress)
291 				ep = find_ep (gadget, "ep5in");
292 			else
293 				ep = find_ep (gadget, "ep6out");
294 		} else if (USB_ENDPOINT_XFER_INT == type) {
295 			if (USB_DIR_IN & desc->bEndpointAddress)
296 				ep = find_ep(gadget, "ep1in");
297 			else
298 				ep = find_ep(gadget, "ep2out");
299 		} else
300 			ep = NULL;
301 		if (ep && ep_matches(gadget, ep, desc, ep_comp))
302 			goto found_ep;
303 #endif
304 	}
305 
306 	/* Second, look at endpoints until an unclaimed one looks usable */
307 	list_for_each_entry (ep, &gadget->ep_list, ep_list) {
308 		if (ep_matches(gadget, ep, desc, ep_comp))
309 			goto found_ep;
310 	}
311 
312 	/* Fail */
313 	return NULL;
314 found_ep:
315 	ep->desc = NULL;
316 	ep->comp_desc = NULL;
317 	return ep;
318 }
319 EXPORT_SYMBOL_GPL(usb_ep_autoconfig_ss);
320 
321 /**
322  * usb_ep_autoconfig() - choose an endpoint matching the
323  * descriptor
324  * @gadget: The device to which the endpoint must belong.
325  * @desc: Endpoint descriptor, with endpoint direction and transfer mode
326  *	initialized.  For periodic transfers, the maximum packet
327  *	size must also be initialized.  This is modified on success.
328  *
329  * By choosing an endpoint to use with the specified descriptor, this
330  * routine simplifies writing gadget drivers that work with multiple
331  * USB device controllers.  The endpoint would be passed later to
332  * usb_ep_enable(), along with some descriptor.
333  *
334  * That second descriptor won't always be the same as the first one.
335  * For example, isochronous endpoints can be autoconfigured for high
336  * bandwidth, and then used in several lower bandwidth altsettings.
337  * Also, high and full speed descriptors will be different.
338  *
339  * Be sure to examine and test the results of autoconfiguration on your
340  * hardware.  This code may not make the best choices about how to use the
341  * USB controller, and it can't know all the restrictions that may apply.
342  * Some combinations of driver and hardware won't be able to autoconfigure.
343  *
344  * On success, this returns an un-claimed usb_ep, and modifies the endpoint
345  * descriptor bEndpointAddress.  For bulk endpoints, the wMaxPacket value
346  * is initialized as if the endpoint were used at full speed.  To prevent
347  * the endpoint from being returned by a later autoconfig call, claim it
348  * by assigning ep->driver_data to some non-null value.
349  *
350  * On failure, this returns a null endpoint descriptor.
351  */
352 struct usb_ep *usb_ep_autoconfig(
353 	struct usb_gadget		*gadget,
354 	struct usb_endpoint_descriptor	*desc
355 )
356 {
357 	return usb_ep_autoconfig_ss(gadget, desc, NULL);
358 }
359 EXPORT_SYMBOL_GPL(usb_ep_autoconfig);
360 
361 /**
362  * usb_ep_autoconfig_reset - reset endpoint autoconfig state
363  * @gadget: device for which autoconfig state will be reset
364  *
365  * Use this for devices where one configuration may need to assign
366  * endpoint resources very differently from the next one.  It clears
367  * state such as ep->driver_data and the record of assigned endpoints
368  * used by usb_ep_autoconfig().
369  */
370 void usb_ep_autoconfig_reset (struct usb_gadget *gadget)
371 {
372 	struct usb_ep	*ep;
373 
374 	list_for_each_entry (ep, &gadget->ep_list, ep_list) {
375 		ep->driver_data = NULL;
376 	}
377 	gadget->in_epnum = 0;
378 	gadget->out_epnum = 0;
379 }
380 EXPORT_SYMBOL_GPL(usb_ep_autoconfig_reset);
381