drivers/usb/gadget/epautoconf.c

   1 /*
   2  * epautoconf.c -- endpoint autoconfiguration for usb gadget drivers
   3  *
   4  * Copyright (C) 2004 David Brownell
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  *
   8  * SPDX-License-Identifier:     GPL-2.0+
   9  *
  10  * Ported to U-boot by: Thomas Smits <ts.smits@gmail.com> and
  11  *                      Remy Bohmer <linux@bohmer.net>
  12  */
  13
  14 #include <common.h>
  15 #include <linux/usb/ch9.h>
  16 #include <asm/errno.h>
  17 #include <linux/usb/gadget.h>
  18 #include <asm/unaligned.h>
  19 #include "gadget_chips.h"
  20
  21 #define isdigit(c)      ('0' <= (c) && (c) <= '9')
  22
  23 /* we must assign addresses for configurable endpoints (like net2280) */
  24 static unsigned epnum;
  25
  26 /* #define MANY_ENDPOINTS */
  27 #ifdef MANY_ENDPOINTS
  28 /* more than 15 configurable endpoints */
  29 static unsigned in_epnum;
  30 #endif
  31
  32
  33 /*
  34  * This should work with endpoints from controller drivers sharing the
  35  * same endpoint naming convention.  By example:
  36  *
  37  *      - ep1, ep2, ... address is fixed, not direction or type
  38  *      - ep1in, ep2out, ... address and direction are fixed, not type
  39  *      - ep1-bulk, ep2-bulk, ... address and type are fixed, not direction
  40  *      - ep1in-bulk, ep2out-iso, ... all three are fixed
  41  *      - ep-* ... no functionality restrictions
  42  *
  43  * Type suffixes are "-bulk", "-iso", or "-int".  Numbers are decimal.
  44  * Less common restrictions are implied by gadget_is_*().
  45  *
  46  * NOTE:  each endpoint is unidirectional, as specified by its USB
  47  * descriptor; and isn't specific to a configuration or altsetting.
  48  */
  49 static int ep_matches(
  50         struct usb_gadget               *gadget,
  51         struct usb_ep                   *ep,
  52         struct usb_endpoint_descriptor  *desc
  53 )
  54 {
  55         u8              type;
  56         const char      *tmp;
  57         u16             max;
  58
  59         /* endpoint already claimed? */
  60         if (NULL != ep->driver_data)
  61                 return 0;
  62
  63         /* only support ep0 for portable CONTROL traffic */
  64         type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
  65         if (USB_ENDPOINT_XFER_CONTROL == type)
  66                 return 0;
  67
  68         /* some other naming convention */
  69         if ('e' != ep->name[0])
  70                 return 0;
  71
  72         /* type-restriction:  "-iso", "-bulk", or "-int".
  73          * direction-restriction:  "in", "out".
  74          */
  75         if ('-' != ep->name[2]) {
  76                 tmp = strrchr(ep->name, '-');
  77                 if (tmp) {
  78                         switch (type) {
  79                         case USB_ENDPOINT_XFER_INT:
  80                                 /* bulk endpoints handle interrupt transfers,
  81                                  * except the toggle-quirky iso-synch kind
  82                                  */
  83                                 if ('s' == tmp[2])      /* == "-iso" */
  84                                         return 0;
  85                                 /* for now, avoid PXA "interrupt-in";
  86                                  * it's documented as never using DATA1.
  87                                  */
  88                                 if (gadget_is_pxa(gadget)
  89                                                 && 'i' == tmp[1])
  90                                         return 0;
  91                                 break;
  92                         case USB_ENDPOINT_XFER_BULK:
  93                                 if ('b' != tmp[1])      /* != "-bulk" */
  94                                         return 0;
  95                                 break;
  96                         case USB_ENDPOINT_XFER_ISOC:
  97                                 if ('s' != tmp[2])      /* != "-iso" */
  98                                         return 0;
  99                         }
 100                 } else {
 101                         tmp = ep->name + strlen(ep->name);
 102                 }
 103
 104                 /* direction-restriction:  "..in-..", "out-.." */
 105                 tmp--;
 106                 if (!isdigit(*tmp)) {
 107                         if (desc->bEndpointAddress & USB_DIR_IN) {
 108                                 if ('n' != *tmp)
 109                                         return 0;
 110                         } else {
 111                                 if ('t' != *tmp)
 112                                         return 0;
 113                         }
 114                 }
 115         }
 116
 117         /* endpoint maxpacket size is an input parameter, except for bulk
 118          * where it's an output parameter representing the full speed limit.
 119          * the usb spec fixes high speed bulk maxpacket at 512 bytes.
 120          */
 121         max = 0x7ff & le16_to_cpu(get_unaligned(&desc->wMaxPacketSize));
 122         switch (type) {
 123         case USB_ENDPOINT_XFER_INT:
 124                 /* INT:  limit 64 bytes full speed, 1024 high speed */
 125                 if (!gadget->is_dualspeed && max > 64)
 126                         return 0;
 127                 /* FALLTHROUGH */
 128
 129         case USB_ENDPOINT_XFER_ISOC:
 130                 /* ISO:  limit 1023 bytes full speed, 1024 high speed */
 131                 if (ep->maxpacket < max)
 132                         return 0;
 133                 if (!gadget->is_dualspeed && max > 1023)
 134                         return 0;
 135
 136                 /* BOTH:  "high bandwidth" works only at high speed */
 137                 if ((get_unaligned(&desc->wMaxPacketSize) &
 138                                         __constant_cpu_to_le16(3<<11))) {
 139                         if (!gadget->is_dualspeed)
 140                                 return 0;
 141                         /* configure your hardware with enough buffering!! */
 142                 }
 143                 break;
 144         }
 145
 146         /* MATCH!! */
 147
 148         /* report address */
 149         if (isdigit(ep->name[2])) {
 150                 u8      num = simple_strtoul(&ep->name[2], NULL, 10);
 151                 desc->bEndpointAddress |= num;
 152 #ifdef  MANY_ENDPOINTS
 153         } else if (desc->bEndpointAddress & USB_DIR_IN) {
 154                 if (++in_epnum > 15)
 155                         return 0;
 156                 desc->bEndpointAddress = USB_DIR_IN | in_epnum;
 157 #endif
 158         } else {
 159                 if (++epnum > 15)
 160                         return 0;
 161                 desc->bEndpointAddress |= epnum;
 162         }
 163
 164         /* report (variable) full speed bulk maxpacket */
 165         if (USB_ENDPOINT_XFER_BULK == type) {
 166                 int size = ep->maxpacket;
 167
 168                 /* min() doesn't work on bitfields with gcc-3.5 */
 169                 if (size > 64)
 170                         size = 64;
 171                 put_unaligned(cpu_to_le16(size), &desc->wMaxPacketSize);
 172         }
 173         return 1;
 174 }
 175
 176 static struct usb_ep *
 177 find_ep(struct usb_gadget *gadget, const char *name)
 178 {
 179         struct usb_ep   *ep;
 180
 181         list_for_each_entry(ep, &gadget->ep_list, ep_list) {
 182                 if (0 == strcmp(ep->name, name))
 183                         return ep;
 184         }
 185         return NULL;
 186 }
 187
 188 /**
 189  * usb_ep_autoconfig - choose an endpoint matching the descriptor
 190  * @gadget: The device to which the endpoint must belong.
 191  * @desc: Endpoint descriptor, with endpoint direction and transfer mode
 192  *      initialized.  For periodic transfers, the maximum packet
 193  *      size must also be initialized.  This is modified on success.
 194  *
 195  * By choosing an endpoint to use with the specified descriptor, this
 196  * routine simplifies writing gadget drivers that work with multiple
 197  * USB device controllers.  The endpoint would be passed later to
 198  * usb_ep_enable(), along with some descriptor.
 199  *
 200  * That second descriptor won't always be the same as the first one.
 201  * For example, isochronous endpoints can be autoconfigured for high
 202  * bandwidth, and then used in several lower bandwidth altsettings.
 203  * Also, high and full speed descriptors will be different.
 204  *
 205  * Be sure to examine and test the results of autoconfiguration on your
 206  * hardware.  This code may not make the best choices about how to use the
 207  * USB controller, and it can't know all the restrictions that may apply.
 208  * Some combinations of driver and hardware won't be able to autoconfigure.
 209  *
 210  * On success, this returns an un-claimed usb_ep, and modifies the endpoint
 211  * descriptor bEndpointAddress.  For bulk endpoints, the wMaxPacket value
 212  * is initialized as if the endpoint were used at full speed.  To prevent
 213  * the endpoint from being returned by a later autoconfig call, claim it
 214  * by assigning ep->driver_data to some non-null value.
 215  *
 216  * On failure, this returns a null endpoint descriptor.
 217  */
 218 struct usb_ep *usb_ep_autoconfig(
 219         struct usb_gadget               *gadget,
 220         struct usb_endpoint_descriptor  *desc
 221 )
 222 {
 223         struct usb_ep   *ep;
 224         u8              type;
 225
 226         type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
 227
 228         /* First, apply chip-specific "best usage" knowledge.
 229          * This might make a good usb_gadget_ops hook ...
 230          */
 231         if (gadget_is_net2280(gadget) && type == USB_ENDPOINT_XFER_INT) {
 232                 /* ep-e, ep-f are PIO with only 64 byte fifos */
 233                 ep = find_ep(gadget, "ep-e");
 234                 if (ep && ep_matches(gadget, ep, desc))
 235                         return ep;
 236                 ep = find_ep(gadget, "ep-f");
 237                 if (ep && ep_matches(gadget, ep, desc))
 238                         return ep;
 239
 240         } else if (gadget_is_goku(gadget)) {
 241                 if (USB_ENDPOINT_XFER_INT == type) {
 242                         /* single buffering is enough */
 243                         ep = find_ep(gadget, "ep3-bulk");
 244                         if (ep && ep_matches(gadget, ep, desc))
 245                                 return ep;
 246                 } else if (USB_ENDPOINT_XFER_BULK == type
 247                                 && (USB_DIR_IN & desc->bEndpointAddress)) {
 248                         /* DMA may be available */
 249                         ep = find_ep(gadget, "ep2-bulk");
 250                         if (ep && ep_matches(gadget, ep, desc))
 251                                 return ep;
 252                 }
 253
 254         } else if (gadget_is_sh(gadget) && USB_ENDPOINT_XFER_INT == type) {
 255                 /* single buffering is enough; maybe 8 byte fifo is too */
 256                 ep = find_ep(gadget, "ep3in-bulk");
 257                 if (ep && ep_matches(gadget, ep, desc))
 258                         return ep;
 259
 260         } else if (gadget_is_mq11xx(gadget) && USB_ENDPOINT_XFER_INT == type) {
 261                 ep = find_ep(gadget, "ep1-bulk");
 262                 if (ep && ep_matches(gadget, ep, desc))
 263                         return ep;
 264         }
 265
 266         /* Second, look at endpoints until an unclaimed one looks usable */
 267         list_for_each_entry(ep, &gadget->ep_list, ep_list) {
 268                 if (ep_matches(gadget, ep, desc))
 269                         return ep;
 270         }
 271
 272         /* Fail */
 273         return NULL;
 274 }
 275
 276 /**
 277  * usb_ep_autoconfig_reset - reset endpoint autoconfig state
 278  * @gadget: device for which autoconfig state will be reset
 279  *
 280  * Use this for devices where one configuration may need to assign
 281  * endpoint resources very differently from the next one.  It clears
 282  * state such as ep->driver_data and the record of assigned endpoints
 283  * used by usb_ep_autoconfig().
 284  */
 285 void usb_ep_autoconfig_reset(struct usb_gadget *gadget)
 286 {
 287         struct usb_ep   *ep;
 288
 289         list_for_each_entry(ep, &gadget->ep_list, ep_list) {
 290                 ep->driver_data = NULL;
 291         }
 292 #ifdef  MANY_ENDPOINTS
 293         in_epnum = 0;
 294 #endif
 295         epnum = 0;
 296 }