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/string.h>
  12 #include <linux/string_helpers.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                         string_upper(p, p);
  78                         if (!strcmp(p, "MFG") || !strcmp(p, "MANUFACTURER")) {
  79                                 kfree(info->mfr);
  80                                 info->mfr = kstrdup(sep, GFP_KERNEL);
  81                         } else if (!strcmp(p, "MDL") || !strcmp(p, "MODEL")) {
  82                                 kfree(info->model);
  83                                 info->model = kstrdup(sep, GFP_KERNEL);
  84                         } else if (!strcmp(p, "CLS") || !strcmp(p, "CLASS")) {
  85                                 int i;
  86
  87                                 kfree(info->class_name);
  88                                 info->class_name = kstrdup(sep, GFP_KERNEL);
  89                                 string_upper(sep, sep);
  90                                 for (i = 0; classes[i].token; i++) {
  91                                         if (!strcmp(classes[i].token, sep)) {
  92                                                 info->class = i;
  93                                                 goto rock_on;
  94                                         }
  95                                 }
  96                                 pr_warn("%s probe: warning, class '%s' not understood\n",
  97                                         port->name, sep);
  98                                 info->class = PARPORT_CLASS_OTHER;
  99                         } else if (!strcmp(p, "CMD") ||
 100                                    !strcmp(p, "COMMAND SET")) {
 101                                 kfree(info->cmdset);
 102                                 info->cmdset = kstrdup(sep, GFP_KERNEL);
 103                                 /* if it speaks printer language, it's
 104                                    probably a printer */
 105                                 if (strstr(sep, "PJL") || strstr(sep, "PCL"))
 106                                         guessed_class = PARPORT_CLASS_PRINTER;
 107                         } else if (!strcmp(p, "DES") || !strcmp(p, "DESCRIPTION")) {
 108                                 kfree(info->description);
 109                                 info->description = kstrdup(sep, GFP_KERNEL);
 110                         }
 111                 }
 112         rock_on:
 113                 if (q)
 114                         p = q + 1;
 115                 else
 116                         p = NULL;
 117         }
 118
 119         /* If the device didn't tell us its class, maybe we have managed to
 120            guess one from the things it did say. */
 121         if (info->class == PARPORT_CLASS_UNSPEC)
 122                 info->class = guessed_class;
 123
 124         pretty_print (port, device);
 125
 126         kfree(txt);
 127 }
 128
 129 /* Read up to count-1 bytes of device id. Terminate buffer with
 130  * '\0'. Buffer begins with two Device ID length bytes as given by
 131  * device. */
 132 static ssize_t parport_read_device_id (struct parport *port, char *buffer,
 133                                        size_t count)
 134 {
 135         unsigned char length[2];
 136         unsigned lelen, belen;
 137         size_t idlens[4];
 138         unsigned numidlens;
 139         unsigned current_idlen;
 140         ssize_t retval;
 141         size_t len;
 142
 143         /* First two bytes are MSB,LSB of inclusive length. */
 144         retval = parport_read (port, length, 2);
 145
 146         if (retval < 0)
 147                 return retval;
 148         if (retval != 2)
 149                 return -EIO;
 150
 151         if (count < 2)
 152                 return 0;
 153         memcpy(buffer, length, 2);
 154         len = 2;
 155
 156         /* Some devices wrongly send LE length, and some send it two
 157          * bytes short. Construct a sorted array of lengths to try. */
 158         belen = (length[0] << 8) + length[1];
 159         lelen = (length[1] << 8) + length[0];
 160         idlens[0] = min(belen, lelen);
 161         idlens[1] = idlens[0]+2;
 162         if (belen != lelen) {
 163                 int off = 2;
 164                 /* Don't try lengths of 0x100 and 0x200 as 1 and 2 */
 165                 if (idlens[0] <= 2)
 166                         off = 0;
 167                 idlens[off] = max(belen, lelen);
 168                 idlens[off+1] = idlens[off]+2;
 169                 numidlens = off+2;
 170         }
 171         else {
 172                 /* Some devices don't truly implement Device ID, but
 173                  * just return constant nibble forever. This catches
 174                  * also those cases. */
 175                 if (idlens[0] == 0 || idlens[0] > 0xFFF) {
 176                         printk(KERN_DEBUG "%s: reported broken Device ID length of %#zX bytes\n",
 177                                port->name, idlens[0]);
 178                         return -EIO;
 179                 }
 180                 numidlens = 2;
 181         }
 182
 183         /* Try to respect the given ID length despite all the bugs in
 184          * the ID length. Read according to shortest possible ID
 185          * first. */
 186         for (current_idlen = 0; current_idlen < numidlens; ++current_idlen) {
 187                 size_t idlen = idlens[current_idlen];
 188                 if (idlen+1 >= count)
 189                         break;
 190
 191                 retval = parport_read (port, buffer+len, idlen-len);
 192
 193                 if (retval < 0)
 194                         return retval;
 195                 len += retval;
 196
 197                 if (port->physport->ieee1284.phase != IEEE1284_PH_HBUSY_DAVAIL) {
 198                         if (belen != len) {
 199                                 printk(KERN_DEBUG "%s: Device ID was %zd bytes while device told it would be %d bytes\n",
 200                                        port->name, len, belen);
 201                         }
 202                         goto done;
 203                 }
 204
 205                 /* This might end reading the Device ID too
 206                  * soon. Hopefully the needed fields were already in
 207                  * the first 256 bytes or so that we must have read so
 208                  * far. */
 209                 if (buffer[len-1] == ';') {
 210                         printk(KERN_DEBUG "%s: Device ID reading stopped before device told data not available. Current idlen %u of %u, len bytes %02X %02X\n",
 211                                port->name, current_idlen, numidlens,
 212                                length[0], length[1]);
 213                         goto done;
 214                 }
 215         }
 216         if (current_idlen < numidlens) {
 217                 /* Buffer not large enough, read to end of buffer. */
 218                 size_t idlen, len2;
 219                 if (len+1 < count) {
 220                         retval = parport_read (port, buffer+len, count-len-1);
 221                         if (retval < 0)
 222                                 return retval;
 223                         len += retval;
 224                 }
 225                 /* Read the whole ID since some devices would not
 226                  * otherwise give back the Device ID from beginning
 227                  * next time when asked. */
 228                 idlen = idlens[current_idlen];
 229                 len2 = len;
 230                 while(len2 < idlen && retval > 0) {
 231                         char tmp[4];
 232                         retval = parport_read (port, tmp,
 233                                                min(sizeof tmp, idlen-len2));
 234                         if (retval < 0)
 235                                 return retval;
 236                         len2 += retval;
 237                 }
 238         }
 239         /* In addition, there are broken devices out there that don't
 240            even finish off with a semi-colon. We do not need to care
 241            about those at this time. */
 242  done:
 243         buffer[len] = '\0';
 244         return len;
 245 }
 246
 247 /* Get Std 1284 Device ID. */
 248 ssize_t parport_device_id (int devnum, char *buffer, size_t count)
 249 {
 250         ssize_t retval = -ENXIO;
 251         struct pardevice *dev = parport_open(devnum, daisy_dev_name);
 252         if (!dev)
 253                 return -ENXIO;
 254
 255         parport_claim_or_block (dev);
 256
 257         /* Negotiate to compatibility mode, and then to device ID
 258          * mode. (This so that we start form beginning of device ID if
 259          * already in device ID mode.) */
 260         parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
 261         retval = parport_negotiate (dev->port,
 262                                     IEEE1284_MODE_NIBBLE | IEEE1284_DEVICEID);
 263
 264         if (!retval) {
 265                 retval = parport_read_device_id (dev->port, buffer, count);
 266                 parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
 267                 if (retval > 2)
 268                         parse_data (dev->port, dev->daisy, buffer+2);
 269         }
 270
 271         parport_release (dev);
 272         parport_close (dev);
 273         return retval;
 274 }