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 __initdata unsigned epnum;
  38
  39 // #define MANY_ENDPOINTS
  40 #ifdef MANY_ENDPOINTS
  41 /* more than 15 configurable endpoints */
  42 static __initdata 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 __init
  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         /* endpoint maxpacket size is an input parameter, except for bulk
 132          * where it's an output parameter representing the full speed limit.
 133          * the usb spec fixes high speed bulk maxpacket at 512 bytes.
 134          */
 135         max = 0x7ff & le16_to_cpu(desc->wMaxPacketSize);
 136         switch (type) {
 137         case USB_ENDPOINT_XFER_INT:
 138                 /* INT:  limit 64 bytes full speed, 1024 high speed */
 139                 if (!gadget->is_dualspeed && max > 64)
 140                         return 0;
 141                 /* FALLTHROUGH */
 142
 143         case USB_ENDPOINT_XFER_ISOC:
 144                 /* ISO:  limit 1023 bytes full speed, 1024 high speed */
 145                 if (ep->maxpacket < max)
 146                         return 0;
 147                 if (!gadget->is_dualspeed && max > 1023)
 148                         return 0;
 149
 150                 /* BOTH:  "high bandwidth" works only at high speed */
 151                 if ((desc->wMaxPacketSize & __constant_cpu_to_le16(3<<11))) {
 152                         if (!gadget->is_dualspeed)
 153                                 return 0;
 154                         /* configure your hardware with enough buffering!! */
 155                 }
 156                 break;
 157         }
 158
 159         /* MATCH!! */
 160
 161         /* report address */
 162         if (isdigit (ep->name [2])) {
 163                 u8      num = simple_strtol (&ep->name [2], NULL, 10);
 164                 desc->bEndpointAddress |= num;
 165 #ifdef  MANY_ENDPOINTS
 166         } else if (desc->bEndpointAddress & USB_DIR_IN) {
 167                 if (++in_epnum > 15)
 168                         return 0;
 169                 desc->bEndpointAddress = USB_DIR_IN | in_epnum;
 170 #endif
 171         } else {
 172                 if (++epnum > 15)
 173                         return 0;
 174                 desc->bEndpointAddress |= epnum;
 175         }
 176
 177         /* report (variable) full speed bulk maxpacket */
 178         if (USB_ENDPOINT_XFER_BULK == type) {
 179                 int size = ep->maxpacket;
 180
 181                 /* min() doesn't work on bitfields with gcc-3.5 */
 182                 if (size > 64)
 183                         size = 64;
 184                 desc->wMaxPacketSize = cpu_to_le16(size);
 185         }
 186         return 1;
 187 }
 188
 189 static struct usb_ep * __init
 190 find_ep (struct usb_gadget *gadget, const char *name)
 191 {
 192         struct usb_ep   *ep;
 193
 194         list_for_each_entry (ep, &gadget->ep_list, ep_list) {
 195                 if (0 == strcmp (ep->name, name))
 196                         return ep;
 197         }
 198         return NULL;
 199 }
 200
 201 /**
 202  * usb_ep_autoconfig - choose an endpoint matching the descriptor
 203  * @gadget: The device to which the endpoint must belong.
 204  * @desc: Endpoint descriptor, with endpoint direction and transfer mode
 205  *      initialized.  For periodic transfers, the maximum packet
 206  *      size must also be initialized.  This is modified on success.
 207  *
 208  * By choosing an endpoint to use with the specified descriptor, this
 209  * routine simplifies writing gadget drivers that work with multiple
 210  * USB device controllers.  The endpoint would be passed later to
 211  * usb_ep_enable(), along with some descriptor.
 212  *
 213  * That second descriptor won't always be the same as the first one.
 214  * For example, isochronous endpoints can be autoconfigured for high
 215  * bandwidth, and then used in several lower bandwidth altsettings.
 216  * Also, high and full speed descriptors will be different.
 217  *
 218  * Be sure to examine and test the results of autoconfiguration on your
 219  * hardware.  This code may not make the best choices about how to use the
 220  * USB controller, and it can't know all the restrictions that may apply.
 221  * Some combinations of driver and hardware won't be able to autoconfigure.
 222  *
 223  * On success, this returns an un-claimed usb_ep, and modifies the endpoint
 224  * descriptor bEndpointAddress.  For bulk endpoints, the wMaxPacket value
 225  * is initialized as if the endpoint were used at full speed.  To prevent
 226  * the endpoint from being returned by a later autoconfig call, claim it
 227  * by assigning ep->driver_data to some non-null value.
 228  *
 229  * On failure, this returns a null endpoint descriptor.
 230  */
 231 struct usb_ep * __init usb_ep_autoconfig (
 232         struct usb_gadget               *gadget,
 233         struct usb_endpoint_descriptor  *desc
 234 )
 235 {
 236         struct usb_ep   *ep;
 237         u8              type;
 238
 239         type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
 240
 241         /* First, apply chip-specific "best usage" knowledge.
 242          * This might make a good usb_gadget_ops hook ...
 243          */
 244         if (gadget_is_net2280 (gadget) && type == USB_ENDPOINT_XFER_INT) {
 245                 /* ep-e, ep-f are PIO with only 64 byte fifos */
 246                 ep = find_ep (gadget, "ep-e");
 247                 if (ep && ep_matches (gadget, ep, desc))
 248                         return ep;
 249                 ep = find_ep (gadget, "ep-f");
 250                 if (ep && ep_matches (gadget, ep, desc))
 251                         return ep;
 252
 253         } else if (gadget_is_goku (gadget)) {
 254                 if (USB_ENDPOINT_XFER_INT == type) {
 255                         /* single buffering is enough */
 256                         ep = find_ep (gadget, "ep3-bulk");
 257                         if (ep && ep_matches (gadget, ep, desc))
 258                                 return ep;
 259                 } else if (USB_ENDPOINT_XFER_BULK == type
 260                                 && (USB_DIR_IN & desc->bEndpointAddress)) {
 261                         /* DMA may be available */
 262                         ep = find_ep (gadget, "ep2-bulk");
 263                         if (ep && ep_matches (gadget, ep, desc))
 264                                 return ep;
 265                 }
 266
 267         } else if (gadget_is_sh (gadget) && USB_ENDPOINT_XFER_INT == type) {
 268                 /* single buffering is enough; maybe 8 byte fifo is too */
 269                 ep = find_ep (gadget, "ep3in-bulk");
 270                 if (ep && ep_matches (gadget, ep, desc))
 271                         return ep;
 272
 273         } else if (gadget_is_mq11xx (gadget) && USB_ENDPOINT_XFER_INT == type) {
 274                 ep = find_ep (gadget, "ep1-bulk");
 275                 if (ep && ep_matches (gadget, ep, desc))
 276                         return ep;
 277         }
 278
 279         /* Second, look at endpoints until an unclaimed one looks usable */
 280         list_for_each_entry (ep, &gadget->ep_list, ep_list) {
 281                 if (ep_matches (gadget, ep, desc))
 282                         return ep;
 283         }
 284
 285         /* Fail */
 286         return NULL;
 287 }
 288
 289 /**
 290  * usb_ep_autoconfig_reset - reset endpoint autoconfig state
 291  * @gadget: device for which autoconfig state will be reset
 292  *
 293  * Use this for devices where one configuration may need to assign
 294  * endpoint resources very differently from the next one.  It clears
 295  * state such as ep->driver_data and the record of assigned endpoints
 296  * used by usb_ep_autoconfig().
 297  */
 298 void __init usb_ep_autoconfig_reset (struct usb_gadget *gadget)
 299 {
 300         struct usb_ep   *ep;
 301
 302         list_for_each_entry (ep, &gadget->ep_list, ep_list) {
 303                 ep->driver_data = NULL;
 304         }
 305 #ifdef  MANY_ENDPOINTS
 306         in_epnum = 0;
 307 #endif
 308         epnum = 0;
 309 }
 310