drivers/parport/probe.c

   1 /*
   2  * Parallel port device probing code
   3  *
   4  * Authors:    Carsten Gross, carsten@sol.wohnheim.uni-ulm.de
   5  *             Philip Blundell <philb@gnu.org>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/parport.h>
  10 #include <linux/ctype.h>
  11 #include <linux/string.h>
  12 #include <linux/slab.h>
  13 #include <linux/uaccess.h>
  14
  15 static const struct {
  16         const char *token;
  17         const char *descr;
  18 } classes[] = {
  19         { "",            "Legacy device" },
  20         { "PRINTER",     "Printer" },
  21         { "MODEM",       "Modem" },
  22         { "NET",         "Network device" },
  23         { "HDC",         "Hard disk" },
  24         { "PCMCIA",      "PCMCIA" },
  25         { "MEDIA",       "Multimedia device" },
  26         { "FDC",         "Floppy disk" },
  27         { "PORTS",       "Ports" },
  28         { "SCANNER",     "Scanner" },
  29         { "DIGICAM",     "Digital camera" },
  30         { "",            "Unknown device" },
  31         { "",            "Unspecified" },
  32         { "SCSIADAPTER", "SCSI adapter" },
  33         { NULL,          NULL }
  34 };
  35
  36 static void pretty_print(struct parport *port, int device)
  37 {
  38         struct parport_device_info *info = &port->probe_info[device + 1];
  39
  40         printk(KERN_INFO "%s", port->name);
  41
  42         if (device >= 0)
  43                 printk (" (addr %d)", device);
  44
  45         printk (": %s", classes[info->class].descr);
  46         if (info->class)
  47                 printk(", %s %s", info->mfr, info->model);
  48
  49         printk("\n");
  50 }
  51
  52 static void parse_data(struct parport *port, int device, char *str)
  53 {
  54         char *txt = kmalloc(strlen(str)+1, GFP_KERNEL);
  55         char *p = txt, *q;
  56         int guessed_class = PARPORT_CLASS_UNSPEC;
  57         struct parport_device_info *info = &port->probe_info[device + 1];
  58
  59         if (!txt) {
  60                 printk(KERN_WARNING "%s probe: memory squeeze\n", port->name);
  61                 return;
  62         }
  63         strcpy(txt, str);
  64         while (p) {
  65                 char *sep;
  66                 q = strchr(p, ';');
  67                 if (q) *q = 0;
  68                 sep = strchr(p, ':');
  69                 if (sep) {
  70                         char *u;
  71                         *(sep++) = 0;
  72                         /* Get rid of trailing blanks */
  73                         u = sep + strlen (sep) - 1;
  74                         while (u >= p && *u == ' ')
  75                                 *u-- = '\0';
  76                         u = p;
  77                         while (*u) {
  78                                 *u = toupper(*u);
  79                                 u++;
  80                         }
  81                         if (!strcmp(p, "MFG") || !strcmp(p, "MANUFACTURER")) {
  82                                 kfree(info->mfr);
  83                                 info->mfr = kstrdup(sep, GFP_KERNEL);
  84                         } else if (!strcmp(p, "MDL") || !strcmp(p, "MODEL")) {
  85                                 kfree(info->model);
  86                                 info->model = kstrdup(sep, GFP_KERNEL);
  87                         } else if (!strcmp(p, "CLS") || !strcmp(p, "CLASS")) {
  88                                 int i;
  89
  90                                 kfree(info->class_name);
  91                                 info->class_name = kstrdup(sep, GFP_KERNEL);
  92                                 for (u = sep; *u; u++)
  93                                         *u = toupper(*u);
  94                                 for (i = 0; classes[i].token; i++) {
  95                                         if (!strcmp(classes[i].token, sep)) {
  96                                                 info->class = i;
  97                                                 goto rock_on;
  98                                         }
  99                                 }
 100                                 printk(KERN_WARNING "%s probe: warning, class '%s' not understood.\n", port->name, sep);
 101                                 info->class = PARPORT_CLASS_OTHER;
 102                         } else if (!strcmp(p, "CMD") ||
 103                                    !strcmp(p, "COMMAND SET")) {
 104                                 kfree(info->cmdset);
 105                                 info->cmdset = kstrdup(sep, GFP_KERNEL);
 106                                 /* if it speaks printer language, it's
 107                                    probably a printer */
 108                                 if (strstr(sep, "PJL") || strstr(sep, "PCL"))
 109                                         guessed_class = PARPORT_CLASS_PRINTER;
 110                         } else if (!strcmp(p, "DES") || !strcmp(p, "DESCRIPTION")) {
 111                                 kfree(info->description);
 112                                 info->description = kstrdup(sep, GFP_KERNEL);
 113                         }
 114                 }
 115         rock_on:
 116                 if (q)
 117                         p = q + 1;
 118                 else
 119                         p = NULL;
 120         }
 121
 122         /* If the device didn't tell us its class, maybe we have managed to
 123            guess one from the things it did say. */
 124         if (info->class == PARPORT_CLASS_UNSPEC)
 125                 info->class = guessed_class;
 126
 127         pretty_print (port, device);
 128
 129         kfree(txt);
 130 }
 131
 132 /* Read up to count-1 bytes of device id. Terminate buffer with
 133  * '\0'. Buffer begins with two Device ID length bytes as given by
 134  * device. */
 135 static ssize_t parport_read_device_id (struct parport *port, char *buffer,
 136                                        size_t count)
 137 {
 138         unsigned char length[2];
 139         unsigned lelen, belen;
 140         size_t idlens[4];
 141         unsigned numidlens;
 142         unsigned current_idlen;
 143         ssize_t retval;
 144         size_t len;
 145
 146         /* First two bytes are MSB,LSB of inclusive length. */
 147         retval = parport_read (port, length, 2);
 148
 149         if (retval < 0)
 150                 return retval;
 151         if (retval != 2)
 152                 return -EIO;
 153
 154         if (count < 2)
 155                 return 0;
 156         memcpy(buffer, length, 2);
 157         len = 2;
 158
 159         /* Some devices wrongly send LE length, and some send it two
 160          * bytes short. Construct a sorted array of lengths to try. */
 161         belen = (length[0] << 8) + length[1];
 162         lelen = (length[1] << 8) + length[0];
 163         idlens[0] = min(belen, lelen);
 164         idlens[1] = idlens[0]+2;
 165         if (belen != lelen) {
 166                 int off = 2;
 167                 /* Don't try lengths of 0x100 and 0x200 as 1 and 2 */
 168                 if (idlens[0] <= 2)
 169                         off = 0;
 170                 idlens[off] = max(belen, lelen);
 171                 idlens[off+1] = idlens[off]+2;
 172                 numidlens = off+2;
 173         }
 174         else {
 175                 /* Some devices don't truly implement Device ID, but
 176                  * just return constant nibble forever. This catches
 177                  * also those cases. */
 178                 if (idlens[0] == 0 || idlens[0] > 0xFFF) {
 179                         printk (KERN_DEBUG "%s: reported broken Device ID"
 180                                 " length of %#zX bytes\n",
 181                                 port->name, idlens[0]);
 182                         return -EIO;
 183                 }
 184                 numidlens = 2;
 185         }
 186
 187         /* Try to respect the given ID length despite all the bugs in
 188          * the ID length. Read according to shortest possible ID
 189          * first. */
 190         for (current_idlen = 0; current_idlen < numidlens; ++current_idlen) {
 191                 size_t idlen = idlens[current_idlen];
 192                 if (idlen+1 >= count)
 193                         break;
 194
 195                 retval = parport_read (port, buffer+len, idlen-len);
 196
 197                 if (retval < 0)
 198                         return retval;
 199                 len += retval;
 200
 201                 if (port->physport->ieee1284.phase != IEEE1284_PH_HBUSY_DAVAIL) {
 202                         if (belen != len) {
 203                                 printk (KERN_DEBUG "%s: Device ID was %zd bytes"
 204                                         " while device told it would be %d"
 205                                         " bytes\n",
 206                                         port->name, len, belen);
 207                         }
 208                         goto done;
 209                 }
 210
 211                 /* This might end reading the Device ID too
 212                  * soon. Hopefully the needed fields were already in
 213                  * the first 256 bytes or so that we must have read so
 214                  * far. */
 215                 if (buffer[len-1] == ';') {
 216                         printk (KERN_DEBUG "%s: Device ID reading stopped"
 217                                 " before device told data not available. "
 218                                 "Current idlen %u of %u, len bytes %02X %02X\n",
 219                                 port->name, current_idlen, numidlens,
 220                                 length[0], length[1]);
 221                         goto done;
 222                 }
 223         }
 224         if (current_idlen < numidlens) {
 225                 /* Buffer not large enough, read to end of buffer. */
 226                 size_t idlen, len2;
 227                 if (len+1 < count) {
 228                         retval = parport_read (port, buffer+len, count-len-1);
 229                         if (retval < 0)
 230                                 return retval;
 231                         len += retval;
 232                 }
 233                 /* Read the whole ID since some devices would not
 234                  * otherwise give back the Device ID from beginning
 235                  * next time when asked. */
 236                 idlen = idlens[current_idlen];
 237                 len2 = len;
 238                 while(len2 < idlen && retval > 0) {
 239                         char tmp[4];
 240                         retval = parport_read (port, tmp,
 241                                                min(sizeof tmp, idlen-len2));
 242                         if (retval < 0)
 243                                 return retval;
 244                         len2 += retval;
 245                 }
 246         }
 247         /* In addition, there are broken devices out there that don't
 248            even finish off with a semi-colon. We do not need to care
 249            about those at this time. */
 250  done:
 251         buffer[len] = '\0';
 252         return len;
 253 }
 254
 255 /* Get Std 1284 Device ID. */
 256 ssize_t parport_device_id (int devnum, char *buffer, size_t count)
 257 {
 258         ssize_t retval = -ENXIO;
 259         struct pardevice *dev = parport_open (devnum, "Device ID probe");
 260         if (!dev)
 261                 return -ENXIO;
 262
 263         parport_claim_or_block (dev);
 264
 265         /* Negotiate to compatibility mode, and then to device ID
 266          * mode. (This so that we start form beginning of device ID if
 267          * already in device ID mode.) */
 268         parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
 269         retval = parport_negotiate (dev->port,
 270                                     IEEE1284_MODE_NIBBLE | IEEE1284_DEVICEID);
 271
 272         if (!retval) {
 273                 retval = parport_read_device_id (dev->port, buffer, count);
 274                 parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
 275                 if (retval > 2)
 276                         parse_data (dev->port, dev->daisy, buffer+2);
 277         }
 278
 279         parport_release (dev);
 280         parport_close (dev);
 281         return retval;
 282 }