// SPDX-License-Identifier: GPL-2.0
/*
* Parallel port device probing code
*
* Authors: Carsten Gross, [email protected]
* Philip Blundell <[email protected]>
*/
#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;
}
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