drivers/parport/probe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Parallel port device probing code
   4  *
   5  * Authors:    Carsten Gross, carsten@sol.wohnheim.uni-ulm.de
   6  *             Philip Blundell <philb@gnu.org>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/parport.h>
  11 #include <linux/ctype.h>
  12 #include <linux/string.h>
  13 #include <linux/slab.h>
  14 #include <linux/uaccess.h>
  15
  16 static const struct {
  17         const char *token;
  18         const char *descr;
  19 } classes[] = {
  20         { "",            "Legacy device" },
  21         { "PRINTER",     "Printer" },
  22         { "MODEM",       "Modem" },
  23         { "NET",         "Network device" },
  24         { "HDC",         "Hard disk" },
  25         { "PCMCIA",      "PCMCIA" },
  26         { "MEDIA",       "Multimedia device" },
  27         { "FDC",         "Floppy disk" },
  28         { "PORTS",       "Ports" },
  29         { "SCANNER",     "Scanner" },
  30         { "DIGICAM",     "Digital camera" },
  31         { "",            "Unknown device" },
  32         { "",            "Unspecified" },
  33         { "SCSIADAPTER", "SCSI adapter" },
  34         { NULL,          NULL }
  35 };
  36
  37 static void pretty_print(struct parport *port, int device)
  38 {
  39         struct parport_device_info *info = &port->probe_info[device + 1];
  40
  41         pr_info("%s", port->name);
  42
  43         if (device >= 0)
  44                 pr_cont(" (addr %d)", device);
  45
  46         pr_cont(": %s", classes[info->class].descr);
  47         if (info->class)
  48                 pr_cont(", %s %s", info->mfr, info->model);
  49
  50         pr_cont("\n");
  51 }
  52
  53 static void parse_data(struct parport *port, int device, char *str)
  54 {
  55         char *txt = kmalloc(strlen(str)+1, GFP_KERNEL);
  56         char *p = txt, *q;
  57         int guessed_class = PARPORT_CLASS_UNSPEC;
  58         struct parport_device_info *info = &port->probe_info[device + 1];
  59
  60         if (!txt) {
  61                 pr_warn("%s probe: memory squeeze\n", port->name);
  62                 return;
  63         }
  64         strcpy(txt, str);
  65         while (p) {
  66                 char *sep;
  67                 q = strchr(p, ';');
  68                 if (q) *q = 0;
  69                 sep = strchr(p, ':');
  70                 if (sep) {
  71                         char *u;
  72                         *(sep++) = 0;
  73                         /* Get rid of trailing blanks */
  74                         u = sep + strlen (sep) - 1;
  75                         while (u >= p && *u == ' ')
  76                                 *u-- = '\0';
  77                         u = p;
  78                         while (*u) {
  79                                 *u = toupper(*u);
  80                                 u++;
  81                         }
  82                         if (!strcmp(p, "MFG") || !strcmp(p, "MANUFACTURER")) {
  83                                 kfree(info->mfr);
  84                                 info->mfr = kstrdup(sep, GFP_KERNEL);
  85                         } else if (!strcmp(p, "MDL") || !strcmp(p, "MODEL")) {
  86                                 kfree(info->model);
  87                                 info->model = kstrdup(sep, GFP_KERNEL);
  88                         } else if (!strcmp(p, "CLS") || !strcmp(p, "CLASS")) {
  89                                 int i;
  90
  91                                 kfree(info->class_name);
  92                                 info->class_name = kstrdup(sep, GFP_KERNEL);
  93                                 for (u = sep; *u; u++)
  94                                         *u = toupper(*u);
  95                                 for (i = 0; classes[i].token; i++) {
  96                                         if (!strcmp(classes[i].token, sep)) {
  97                                                 info->class = i;
  98                                                 goto rock_on;
  99                                         }
 100                                 }
 101                                 pr_warn("%s probe: warning, class '%s' not understood\n",
 102                                         port->name, sep);
 103                                 info->class = PARPORT_CLASS_OTHER;
 104                         } else if (!strcmp(p, "CMD") ||
 105                                    !strcmp(p, "COMMAND SET")) {
 106                                 kfree(info->cmdset);
 107                                 info->cmdset = kstrdup(sep, GFP_KERNEL);
 108                                 /* if it speaks printer language, it's
 109                                    probably a printer */
 110                                 if (strstr(sep, "PJL") || strstr(sep, "PCL"))
 111                                         guessed_class = PARPORT_CLASS_PRINTER;
 112                         } else if (!strcmp(p, "DES") || !strcmp(p, "DESCRIPTION")) {
 113                                 kfree(info->description);
 114                                 info->description = kstrdup(sep, GFP_KERNEL);
 115                         }
 116                 }
 117         rock_on:
 118                 if (q)
 119                         p = q + 1;
 120                 else
 121                         p = NULL;
 122         }
 123
 124         /* If the device didn't tell us its class, maybe we have managed to
 125            guess one from the things it did say. */
 126         if (info->class == PARPORT_CLASS_UNSPEC)
 127                 info->class = guessed_class;
 128
 129         pretty_print (port, device);
 130
 131         kfree(txt);
 132 }
 133
 134 /* Read up to count-1 bytes of device id. Terminate buffer with
 135  * '\0'. Buffer begins with two Device ID length bytes as given by
 136  * device. */
 137 static ssize_t parport_read_device_id (struct parport *port, char *buffer,
 138                                        size_t count)
 139 {
 140         unsigned char length[2];
 141         unsigned lelen, belen;
 142         size_t idlens[4];
 143         unsigned numidlens;
 144         unsigned current_idlen;
 145         ssize_t retval;
 146         size_t len;
 147
 148         /* First two bytes are MSB,LSB of inclusive length. */
 149         retval = parport_read (port, length, 2);
 150
 151         if (retval < 0)
 152                 return retval;
 153         if (retval != 2)
 154                 return -EIO;
 155
 156         if (count < 2)
 157                 return 0;
 158         memcpy(buffer, length, 2);
 159         len = 2;
 160
 161         /* Some devices wrongly send LE length, and some send it two
 162          * bytes short. Construct a sorted array of lengths to try. */
 163         belen = (length[0] << 8) + length[1];
 164         lelen = (length[1] << 8) + length[0];
 165         idlens[0] = min(belen, lelen);
 166         idlens[1] = idlens[0]+2;
 167         if (belen != lelen) {
 168                 int off = 2;
 169                 /* Don't try lengths of 0x100 and 0x200 as 1 and 2 */
 170                 if (idlens[0] <= 2)
 171                         off = 0;
 172                 idlens[off] = max(belen, lelen);
 173                 idlens[off+1] = idlens[off]+2;
 174                 numidlens = off+2;
 175         }
 176         else {
 177                 /* Some devices don't truly implement Device ID, but
 178                  * just return constant nibble forever. This catches
 179                  * also those cases. */
 180                 if (idlens[0] == 0 || idlens[0] > 0xFFF) {
 181                         printk(KERN_DEBUG "%s: reported broken Device ID length of %#zX bytes\n",
 182                                port->name, idlens[0]);
 183                         return -EIO;
 184                 }
 185                 numidlens = 2;
 186         }
 187
 188         /* Try to respect the given ID length despite all the bugs in
 189          * the ID length. Read according to shortest possible ID
 190          * first. */
 191         for (current_idlen = 0; current_idlen < numidlens; ++current_idlen) {
 192                 size_t idlen = idlens[current_idlen];
 193                 if (idlen+1 >= count)
 194                         break;
 195
 196                 retval = parport_read (port, buffer+len, idlen-len);
 197
 198                 if (retval < 0)
 199                         return retval;
 200                 len += retval;
 201
 202                 if (port->physport->ieee1284.phase != IEEE1284_PH_HBUSY_DAVAIL) {
 203                         if (belen != len) {
 204                                 printk(KERN_DEBUG "%s: Device ID was %zd bytes while device told it would be %d bytes\n",
 205                                        port->name, len, belen);
 206                         }
 207                         goto done;
 208                 }
 209
 210                 /* This might end reading the Device ID too
 211                  * soon. Hopefully the needed fields were already in
 212                  * the first 256 bytes or so that we must have read so
 213                  * far. */
 214                 if (buffer[len-1] == ';') {
 215                         printk(KERN_DEBUG "%s: Device ID reading stopped before device told data not available. Current idlen %u of %u, len bytes %02X %02X\n",
 216                                port->name, current_idlen, numidlens,
 217                                length[0], length[1]);
 218                         goto done;
 219                 }
 220         }
 221         if (current_idlen < numidlens) {
 222                 /* Buffer not large enough, read to end of buffer. */
 223                 size_t idlen, len2;
 224                 if (len+1 < count) {
 225                         retval = parport_read (port, buffer+len, count-len-1);
 226                         if (retval < 0)
 227                                 return retval;
 228                         len += retval;
 229                 }
 230                 /* Read the whole ID since some devices would not
 231                  * otherwise give back the Device ID from beginning
 232                  * next time when asked. */
 233                 idlen = idlens[current_idlen];
 234                 len2 = len;
 235                 while(len2 < idlen && retval > 0) {
 236                         char tmp[4];
 237                         retval = parport_read (port, tmp,
 238                                                min(sizeof tmp, idlen-len2));
 239                         if (retval < 0)
 240                                 return retval;
 241                         len2 += retval;
 242                 }
 243         }
 244         /* In addition, there are broken devices out there that don't
 245            even finish off with a semi-colon. We do not need to care
 246            about those at this time. */
 247  done:
 248         buffer[len] = '\0';
 249         return len;
 250 }
 251
 252 /* Get Std 1284 Device ID. */
 253 ssize_t parport_device_id (int devnum, char *buffer, size_t count)
 254 {
 255         ssize_t retval = -ENXIO;
 256         struct pardevice *dev = parport_open(devnum, daisy_dev_name);
 257         if (!dev)
 258                 return -ENXIO;
 259
 260         parport_claim_or_block (dev);
 261
 262         /* Negotiate to compatibility mode, and then to device ID
 263          * mode. (This so that we start form beginning of device ID if
 264          * already in device ID mode.) */
 265         parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
 266         retval = parport_negotiate (dev->port,
 267                                     IEEE1284_MODE_NIBBLE | IEEE1284_DEVICEID);
 268
 269         if (!retval) {
 270                 retval = parport_read_device_id (dev->port, buffer, count);
 271                 parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
 272                 if (retval > 2)
 273                         parse_data (dev->port, dev->daisy, buffer+2);
 274         }
 275
 276         parport_release (dev);
 277         parport_close (dev);
 278         return retval;
 279 }