drivers/usb/gadget/epautoconf.c

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