linux/drivers/parport/probe.c
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   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 <asm/uaccess.h>
  14
  15static 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
  36static 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
  52static 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. */
 135static 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. */
 256ssize_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}
 283
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