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 } 275