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  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/init.h>
  24 #include <linux/types.h>
  25 #include <linux/device.h>
  26
  27 #include <linux/ctype.h>
  28 #include <linux/string.h>
  29
  30 #include <linux/usb/ch9.h>
  31 #include <linux/usb/gadget.h>
  32
  33 #include "gadget_chips.h"
  34
  35
  36 /* we must assign addresses for configurable endpoints (like net2280) */
  37 static unsigned epnum;
  38
  39 // #define MANY_ENDPOINTS
  40 #ifdef MANY_ENDPOINTS
  41 /* more than 15 configurable endpoints */
  42 static unsigned in_epnum;
  43 #endif
  44
  45
  46 /*
  47  * This should work with endpoints from controller drivers sharing the
  48  * same endpoint naming convention.  By example:
  49  *
  50  *      - ep1, ep2, ... address is fixed, not direction or type
  51  *      - ep1in, ep2out, ... address and direction are fixed, not type
  52  *      - ep1-bulk, ep2-bulk, ... address and type are fixed, not direction
  53  *      - ep1in-bulk, ep2out-iso, ... all three are fixed
  54  *      - ep-* ... no functionality restrictions
  55  *
  56  * Type suffixes are "-bulk", "-iso", or "-int".  Numbers are decimal.
  57  * Less common restrictions are implied by gadget_is_*().
  58  *
  59  * NOTE:  each endpoint is unidirectional, as specified by its USB
  60  * descriptor; and isn't specific to a configuration or altsetting.
  61  */
  62 static int
  63 ep_matches (
  64         struct usb_gadget               *gadget,
  65         struct usb_ep                   *ep,
  66         struct usb_endpoint_descriptor  *desc
  67 )
  68 {
  69         u8              type;
  70         const char      *tmp;
  71         u16             max;
  72
  73         /* endpoint already claimed? */
  74         if (NULL != ep->driver_data)
  75                 return 0;
  76
  77         /* only support ep0 for portable CONTROL traffic */
  78         type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
  79         if (USB_ENDPOINT_XFER_CONTROL == type)
  80                 return 0;
  81
  82         /* some other naming convention */
  83         if ('e' != ep->name[0])
  84                 return 0;
  85
  86         /* type-restriction:  "-iso", "-bulk", or "-int".
  87          * direction-restriction:  "in", "out".
  88          */
  89         if ('-' != ep->name[2]) {
  90                 tmp = strrchr (ep->name, '-');
  91                 if (tmp) {
  92                         switch (type) {
  93                         case USB_ENDPOINT_XFER_INT:
  94                                 /* bulk endpoints handle interrupt transfers,
  95                                  * except the toggle-quirky iso-synch kind
  96                                  */
  97                                 if ('s' == tmp[2])      // == "-iso"
  98                                         return 0;
  99                                 /* for now, avoid PXA "interrupt-in";
 100                                  * it's documented as never using DATA1.
 101                                  */
 102                                 if (gadget_is_pxa (gadget)
 103                                                 && 'i' == tmp [1])
 104                                         return 0;
 105                                 break;
 106                         case USB_ENDPOINT_XFER_BULK:
 107                                 if ('b' != tmp[1])      // != "-bulk"
 108                                         return 0;
 109                                 break;
 110                         case USB_ENDPOINT_XFER_ISOC:
 111                                 if ('s' != tmp[2])      // != "-iso"
 112                                         return 0;
 113                         }
 114                 } else {
 115                         tmp = ep->name + strlen (ep->name);
 116                 }
 117
 118                 /* direction-restriction:  "..in-..", "out-.." */
 119                 tmp--;
 120                 if (!isdigit (*tmp)) {
 121                         if (desc->bEndpointAddress & USB_DIR_IN) {
 122                                 if ('n' != *tmp)
 123                                         return 0;
 124                         } else {
 125                                 if ('t' != *tmp)
 126                                         return 0;
 127                         }
 128                 }
 129         }
 130
 131         /*
 132          * If the protocol driver hasn't yet decided on wMaxPacketSize
 133          * and wants to know the maximum possible, provide the info.
 134          */
 135         if (desc->wMaxPacketSize == 0)
 136                 desc->wMaxPacketSize = cpu_to_le16(ep->maxpacket);
 137
 138         /* endpoint maxpacket size is an input parameter, except for bulk
 139          * where it's an output parameter representing the full speed limit.
 140          * the usb spec fixes high speed bulk maxpacket at 512 bytes.
 141          */
 142         max = 0x7ff & le16_to_cpu(desc->wMaxPacketSize);
 143         switch (type) {
 144         case USB_ENDPOINT_XFER_INT:
 145                 /* INT:  limit 64 bytes full speed, 1024 high speed */
 146                 if (!gadget->is_dualspeed && max > 64)
 147                         return 0;
 148                 /* FALLTHROUGH */
 149
 150         case USB_ENDPOINT_XFER_ISOC:
 151                 /* ISO:  limit 1023 bytes full speed, 1024 high speed */
 152                 if (ep->maxpacket < max)
 153                         return 0;
 154                 if (!gadget->is_dualspeed && max > 1023)
 155                         return 0;
 156
 157                 /* BOTH:  "high bandwidth" works only at high speed */
 158                 if ((desc->wMaxPacketSize & cpu_to_le16(3<<11))) {
 159                         if (!gadget->is_dualspeed)
 160                                 return 0;
 161                         /* configure your hardware with enough buffering!! */
 162                 }
 163                 break;
 164         }
 165
 166         /* MATCH!! */
 167
 168         /* report address */
 169         desc->bEndpointAddress &= USB_DIR_IN;
 170         if (isdigit (ep->name [2])) {
 171                 u8      num = simple_strtoul (&ep->name [2], NULL, 10);
 172                 desc->bEndpointAddress |= num;
 173 #ifdef  MANY_ENDPOINTS
 174         } else if (desc->bEndpointAddress & USB_DIR_IN) {
 175                 if (++in_epnum > 15)
 176                         return 0;
 177                 desc->bEndpointAddress = USB_DIR_IN | in_epnum;
 178 #endif
 179         } else {
 180                 if (++epnum > 15)
 181                         return 0;
 182                 desc->bEndpointAddress |= epnum;
 183         }
 184
 185         /* report (variable) full speed bulk maxpacket */
 186         if (USB_ENDPOINT_XFER_BULK == type) {
 187                 int size = ep->maxpacket;
 188
 189                 /* min() doesn't work on bitfields with gcc-3.5 */
 190                 if (size > 64)
 191                         size = 64;
 192                 desc->wMaxPacketSize = cpu_to_le16(size);
 193         }
 194         ep->address = desc->bEndpointAddress;
 195         return 1;
 196 }
 197
 198 static struct usb_ep *
 199 find_ep (struct usb_gadget *gadget, const char *name)
 200 {
 201         struct usb_ep   *ep;
 202
 203         list_for_each_entry (ep, &gadget->ep_list, ep_list) {
 204                 if (0 == strcmp (ep->name, name))
 205                         return ep;
 206         }
 207         return NULL;
 208 }
 209
 210 /**
 211  * usb_ep_autoconfig - choose an endpoint matching the descriptor
 212  * @gadget: The device to which the endpoint must belong.
 213  * @desc: Endpoint descriptor, with endpoint direction and transfer mode
 214  *      initialized.  For periodic transfers, the maximum packet
 215  *      size must also be initialized.  This is modified on success.
 216  *
 217  * By choosing an endpoint to use with the specified descriptor, this
 218  * routine simplifies writing gadget drivers that work with multiple
 219  * USB device controllers.  The endpoint would be passed later to
 220  * usb_ep_enable(), along with some descriptor.
 221  *
 222  * That second descriptor won't always be the same as the first one.
 223  * For example, isochronous endpoints can be autoconfigured for high
 224  * bandwidth, and then used in several lower bandwidth altsettings.
 225  * Also, high and full speed descriptors will be different.
 226  *
 227  * Be sure to examine and test the results of autoconfiguration on your
 228  * hardware.  This code may not make the best choices about how to use the
 229  * USB controller, and it can't know all the restrictions that may apply.
 230  * Some combinations of driver and hardware won't be able to autoconfigure.
 231  *
 232  * On success, this returns an un-claimed usb_ep, and modifies the endpoint
 233  * descriptor bEndpointAddress.  For bulk endpoints, the wMaxPacket value
 234  * is initialized as if the endpoint were used at full speed.  To prevent
 235  * the endpoint from being returned by a later autoconfig call, claim it
 236  * by assigning ep->driver_data to some non-null value.
 237  *
 238  * On failure, this returns a null endpoint descriptor.
 239  */
 240 struct usb_ep *usb_ep_autoconfig (
 241         struct usb_gadget               *gadget,
 242         struct usb_endpoint_descriptor  *desc
 243 )
 244 {
 245         struct usb_ep   *ep;
 246         u8              type;
 247
 248         type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
 249
 250         /* First, apply chip-specific "best usage" knowledge.
 251          * This might make a good usb_gadget_ops hook ...
 252          */
 253         if (gadget_is_net2280 (gadget) && type == USB_ENDPOINT_XFER_INT) {
 254                 /* ep-e, ep-f are PIO with only 64 byte fifos */
 255                 ep = find_ep (gadget, "ep-e");
 256                 if (ep && ep_matches (gadget, ep, desc))
 257                         return ep;
 258                 ep = find_ep (gadget, "ep-f");
 259                 if (ep && ep_matches (gadget, ep, desc))
 260                         return ep;
 261
 262         } else if (gadget_is_goku (gadget)) {
 263                 if (USB_ENDPOINT_XFER_INT == type) {
 264                         /* single buffering is enough */
 265                         ep = find_ep (gadget, "ep3-bulk");
 266                         if (ep && ep_matches (gadget, ep, desc))
 267                                 return ep;
 268                 } else if (USB_ENDPOINT_XFER_BULK == type
 269                                 && (USB_DIR_IN & desc->bEndpointAddress)) {
 270                         /* DMA may be available */
 271                         ep = find_ep (gadget, "ep2-bulk");
 272                         if (ep && ep_matches (gadget, ep, desc))
 273                                 return ep;
 274                 }
 275
 276 #ifdef CONFIG_BLACKFIN
 277         } else if (gadget_is_musbhdrc(gadget)) {
 278                 if ((USB_ENDPOINT_XFER_BULK == type) ||
 279                     (USB_ENDPOINT_XFER_ISOC == type)) {
 280                         if (USB_DIR_IN & desc->bEndpointAddress)
 281                                 ep = find_ep (gadget, "ep5in");
 282                         else
 283                                 ep = find_ep (gadget, "ep6out");
 284                 } else if (USB_ENDPOINT_XFER_INT == type) {
 285                         if (USB_DIR_IN & desc->bEndpointAddress)
 286                                 ep = find_ep(gadget, "ep1in");
 287                         else
 288                                 ep = find_ep(gadget, "ep2out");
 289                 } else
 290                         ep = NULL;
 291                 if (ep && ep_matches (gadget, ep, desc))
 292                         return ep;
 293 #endif
 294         }
 295
 296         /* Second, look at endpoints until an unclaimed one looks usable */
 297         list_for_each_entry (ep, &gadget->ep_list, ep_list) {
 298                 if (ep_matches (gadget, ep, desc))
 299                         return ep;
 300         }
 301
 302         /* Fail */
 303         return NULL;
 304 }
 305
 306 /**
 307  * usb_ep_autoconfig_reset - reset endpoint autoconfig state
 308  * @gadget: device for which autoconfig state will be reset
 309  *
 310  * Use this for devices where one configuration may need to assign
 311  * endpoint resources very differently from the next one.  It clears
 312  * state such as ep->driver_data and the record of assigned endpoints
 313  * used by usb_ep_autoconfig().
 314  */
 315 void usb_ep_autoconfig_reset (struct usb_gadget *gadget)
 316 {
 317         struct usb_ep   *ep;
 318
 319         list_for_each_entry (ep, &gadget->ep_list, ep_list) {
 320                 ep->driver_data = NULL;
 321         }
 322 #ifdef  MANY_ENDPOINTS
 323         in_epnum = 0;
 324 #endif
 325         epnum = 0;
 326 }
 327