// SPDX-License-Identifier: GPL-2.0
/*
 * Parallel port device probing code
 *
 * Authors:    Carsten Gross, carsten@sol.wohnheim.uni-ulm.de
 *             Philip Blundell <philb@gnu.org>
 */

#include <linux/module.h>
#include <linux/parport.h>
#include <linux/string.h>
#include <linux/string_helpers.h>
#include <linux/slab.h>
#include <linux/uaccess.h>

static const struct {
        const char *token;
        const char *descr;
} classes[] = {
        { "",            "Legacy device" },
        { "PRINTER",     "Printer" },
        { "MODEM",       "Modem" },
        { "NET",         "Network device" },
        { "HDC",         "Hard disk" },
        { "PCMCIA",      "PCMCIA" },
        { "MEDIA",       "Multimedia device" },
        { "FDC",         "Floppy disk" },
        { "PORTS",       "Ports" },
        { "SCANNER",     "Scanner" },
        { "DIGICAM",     "Digital camera" },
        { "",            "Unknown device" },
        { "",            "Unspecified" },
        { "SCSIADAPTER", "SCSI adapter" },
        { NULL,          NULL }
};

static void pretty_print(struct parport *port, int device)
{
        struct parport_device_info *info = &port->probe_info[device + 1];

        pr_info("%s", port->name);

        if (device >= 0)
                pr_cont(" (addr %d)", device);

        pr_cont(": %s", classes[info->class].descr);
        if (info->class)
                pr_cont(", %s %s", info->mfr, info->model);

        pr_cont("\n");
}

static void parse_data(struct parport *port, int device, char *str)
{
        char *txt = kmalloc(strlen(str)+1, GFP_KERNEL);
        char *p = txt, *q;
        int guessed_class = PARPORT_CLASS_UNSPEC;
        struct parport_device_info *info = &port->probe_info[device + 1];

        if (!txt) {
                pr_warn("%s probe: memory squeeze\n", port->name);
                return;
        }
        strcpy(txt, str);
        while (p) {
                char *sep;
                q = strchr(p, ';');
                if (q) *q = 0;
                sep = strchr(p, ':');
                if (sep) {
                        char *u;
                        *(sep++) = 0;
                        /* Get rid of trailing blanks */
                        u = sep + strlen (sep) - 1;
                        while (u >= p && *u == ' ')
                                *u-- = '\0';
                        string_upper(p, p);
                        if (!strcmp(p, "MFG") || !strcmp(p, "MANUFACTURER")) {
                                kfree(info->mfr);
                                info->mfr = kstrdup(sep, GFP_KERNEL);
                        } else if (!strcmp(p, "MDL") || !strcmp(p, "MODEL")) {
                                kfree(info->model);
                                info->model = kstrdup(sep, GFP_KERNEL);
                        } else if (!strcmp(p, "CLS") || !strcmp(p, "CLASS")) {
                                int i;

                                kfree(info->class_name);
                                info->class_name = kstrdup(sep, GFP_KERNEL);
                                string_upper(sep, sep);
                                for (i = 0; classes[i].token; i++) {
                                        if (!strcmp(classes[i].token, sep)) {
                                                info->class = i;
                                                goto rock_on;
                                        }
                                }
                                pr_warn("%s probe: warning, class '%s' not understood\n",
                                        port->name, sep);
                                info->class = PARPORT_CLASS_OTHER;
                        } else if (!strcmp(p, "CMD") ||
                                   !strcmp(p, "COMMAND SET")) {
                                kfree(info->cmdset);
                                info->cmdset = kstrdup(sep, GFP_KERNEL);
                                /* if it speaks printer language, it's
                                   probably a printer */
                                if (strstr(sep, "PJL") || strstr(sep, "PCL"))
                                        guessed_class = PARPORT_CLASS_PRINTER;
                        } else if (!strcmp(p, "DES") || !strcmp(p, "DESCRIPTION")) {
                                kfree(info->description);
                                info->description = kstrdup(sep, GFP_KERNEL);
                        }
                }
        rock_on:
                if (q)
                        p = q + 1;
                else
                        p = NULL;
        }

        /* If the device didn't tell us its class, maybe we have managed to
           guess one from the things it did say. */
        if (info->class == PARPORT_CLASS_UNSPEC)
                info->class = guessed_class;

        pretty_print (port, device);

        kfree(txt);
}

/* Read up to count-1 bytes of device id. Terminate buffer with
 * '\0'. Buffer begins with two Device ID length bytes as given by
 * device. */
static ssize_t parport_read_device_id (struct parport *port, char *buffer,
                                       size_t count)
{
        unsigned char length[2];
        unsigned lelen, belen;
        size_t idlens[4];
        unsigned numidlens;
        unsigned current_idlen;
        ssize_t retval;
        size_t len;

        /* First two bytes are MSB,LSB of inclusive length. */
        retval = parport_read (port, length, 2);

        if (retval < 0)
                return retval;
        if (retval != 2)
                return -EIO;

        if (count < 2)
                return 0;
        memcpy(buffer, length, 2);
        len = 2;

        /* Some devices wrongly send LE length, and some send it two
         * bytes short. Construct a sorted array of lengths to try. */
        belen = (length[0] << 8) + length[1];
        lelen = (length[1] << 8) + length[0];
        idlens[0] = min(belen, lelen);
        idlens[1] = idlens[0]+2;
        if (belen != lelen) {
                int off = 2;
                /* Don't try lengths of 0x100 and 0x200 as 1 and 2 */
                if (idlens[0] <= 2)
                        off = 0;
                idlens[off] = max(belen, lelen);
                idlens[off+1] = idlens[off]+2;
                numidlens = off+2;
        }
        else {
                /* Some devices don't truly implement Device ID, but
                 * just return constant nibble forever. This catches
                 * also those cases. */
                if (idlens[0] == 0 || idlens[0] > 0xFFF) {
                        printk(KERN_DEBUG "%s: reported broken Device ID length of %#zX bytes\n",
                               port->name, idlens[0]);
                        return -EIO;
                }
                numidlens = 2;
        }

        /* Try to respect the given ID length despite all the bugs in
         * the ID length. Read according to shortest possible ID
         * first. */
        for (current_idlen = 0; current_idlen < numidlens; ++current_idlen) {
                size_t idlen = idlens[current_idlen];
                if (idlen+1 >= count)
                        break;

                retval = parport_read (port, buffer+len, idlen-len);

                if (retval < 0)
                        return retval;
                len += retval;

                if (port->physport->ieee1284.phase != IEEE1284_PH_HBUSY_DAVAIL) {
                        if (belen != len) {
                                printk(KERN_DEBUG "%s: Device ID was %zd bytes while device told it would be %d bytes\n",
                                       port->name, len, belen);
                        }
                        goto done;
                }

                /* This might end reading the Device ID too
                 * soon. Hopefully the needed fields were already in
                 * the first 256 bytes or so that we must have read so
                 * far. */
                if (buffer[len-1] == ';') {
                        printk(KERN_DEBUG "%s: Device ID reading stopped before device told data not available. Current idlen %u of %u, len bytes %02X %02X\n",
                               port->name, current_idlen, numidlens,
                               length[0], length[1]);
                        goto done;
                }
        }
        if (current_idlen < numidlens) {
                /* Buffer not large enough, read to end of buffer. */
                size_t idlen, len2;
                if (len+1 < count) {
                        retval = parport_read (port, buffer+len, count-len-1);
                        if (retval < 0)
                                return retval;
                        len += retval;
                }
                /* Read the whole ID since some devices would not
                 * otherwise give back the Device ID from beginning
                 * next time when asked. */
                idlen = idlens[current_idlen];
                len2 = len;
                while(len2 < idlen && retval > 0) {
                        char tmp[4];
                        retval = parport_read (port, tmp,
                                               min(sizeof tmp, idlen-len2));
                        if (retval < 0)
                                return retval;
                        len2 += retval;
                }
        }
        /* In addition, there are broken devices out there that don't
           even finish off with a semi-colon. We do not need to care
           about those at this time. */
 done:
        buffer[len] = '\0';
        return len;
}

/* Get Std 1284 Device ID. */
ssize_t parport_device_id (int devnum, char *buffer, size_t count)
{
        ssize_t retval = -ENXIO;
        struct pardevice *dev = parport_open(devnum, daisy_dev_name);
        if (!dev)
                return -ENXIO;

        parport_claim_or_block (dev);

        /* Negotiate to compatibility mode, and then to device ID
         * mode. (This so that we start form beginning of device ID if
         * already in device ID mode.) */
        parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
        retval = parport_negotiate (dev->port,
                                    IEEE1284_MODE_NIBBLE | IEEE1284_DEVICEID);

        if (!retval) {
                retval = parport_read_device_id (dev->port, buffer, count);
                parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
                if (retval > 2)
                        parse_data (dev->port, dev->daisy, buffer+2);
        }

        parport_release (dev);
        parport_close (dev);
        return retval;
}