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 } 280