1 /* 2 * IEEE 1284.3 Parallel port daisy chain and multiplexor code 3 * 4 * Copyright (C) 1999, 2000 Tim Waugh <tim@cyberelk.demon.co.uk> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 * 11 * ??-12-1998: Initial implementation. 12 * 31-01-1999: Make port-cloning transparent. 13 * 13-02-1999: Move DeviceID technique from parport_probe. 14 * 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too. 15 * 22-02-2000: Count devices that are actually detected. 16 * 17 * Any part of this program may be used in documents licensed under 18 * the GNU Free Documentation License, Version 1.1 or any later version 19 * published by the Free Software Foundation. 20 */ 21 22 #include <linux/module.h> 23 #include <linux/parport.h> 24 #include <linux/delay.h> 25 #include <linux/slab.h> 26 #include <linux/sched/signal.h> 27 28 #include <asm/current.h> 29 #include <linux/uaccess.h> 30 31 #undef DEBUG 32 33 static struct daisydev { 34 struct daisydev *next; 35 struct parport *port; 36 int daisy; 37 int devnum; 38 } *topology = NULL; 39 static DEFINE_SPINLOCK(topology_lock); 40 41 static int numdevs; 42 static bool daisy_init_done; 43 44 /* Forward-declaration of lower-level functions. */ 45 static int mux_present(struct parport *port); 46 static int num_mux_ports(struct parport *port); 47 static int select_port(struct parport *port); 48 static int assign_addrs(struct parport *port); 49 50 /* Add a device to the discovered topology. */ 51 static void add_dev(int devnum, struct parport *port, int daisy) 52 { 53 struct daisydev *newdev, **p; 54 newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL); 55 if (newdev) { 56 newdev->port = port; 57 newdev->daisy = daisy; 58 newdev->devnum = devnum; 59 spin_lock(&topology_lock); 60 for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next) 61 ; 62 newdev->next = *p; 63 *p = newdev; 64 spin_unlock(&topology_lock); 65 } 66 } 67 68 /* Clone a parport (actually, make an alias). */ 69 static struct parport *clone_parport(struct parport *real, int muxport) 70 { 71 struct parport *extra = parport_register_port(real->base, 72 real->irq, 73 real->dma, 74 real->ops); 75 if (extra) { 76 extra->portnum = real->portnum; 77 extra->physport = real; 78 extra->muxport = muxport; 79 real->slaves[muxport-1] = extra; 80 } 81 82 return extra; 83 } 84 85 static int daisy_drv_probe(struct pardevice *par_dev) 86 { 87 struct device_driver *drv = par_dev->dev.driver; 88 89 if (strcmp(drv->name, "daisy_drv")) 90 return -ENODEV; 91 if (strcmp(par_dev->name, daisy_dev_name)) 92 return -ENODEV; 93 94 return 0; 95 } 96 97 static struct parport_driver daisy_driver = { 98 .name = "daisy_drv", 99 .probe = daisy_drv_probe, 100 .devmodel = true, 101 }; 102 103 /* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains. 104 * Return value is number of devices actually detected. */ 105 int parport_daisy_init(struct parport *port) 106 { 107 int detected = 0; 108 char *deviceid; 109 static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" }; 110 int num_ports; 111 int i; 112 int last_try = 0; 113 114 if (!daisy_init_done) { 115 /* 116 * flag should be marked true first as 117 * parport_register_driver() might try to load the low 118 * level driver which will lead to announcing new ports 119 * and which will again come back here at 120 * parport_daisy_init() 121 */ 122 daisy_init_done = true; 123 i = parport_register_driver(&daisy_driver); 124 if (i) { 125 pr_err("daisy registration failed\n"); 126 daisy_init_done = false; 127 return i; 128 } 129 } 130 131 again: 132 /* Because this is called before any other devices exist, 133 * we don't have to claim exclusive access. */ 134 135 /* If mux present on normal port, need to create new 136 * parports for each extra port. */ 137 if (port->muxport < 0 && mux_present(port) && 138 /* don't be fooled: a mux must have 2 or 4 ports. */ 139 ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) { 140 /* Leave original as port zero. */ 141 port->muxport = 0; 142 pr_info("%s: 1st (default) port of %d-way multiplexor\n", 143 port->name, num_ports); 144 for (i = 1; i < num_ports; i++) { 145 /* Clone the port. */ 146 struct parport *extra = clone_parport(port, i); 147 if (!extra) { 148 if (signal_pending(current)) 149 break; 150 151 schedule(); 152 continue; 153 } 154 155 pr_info("%s: %d%s port of %d-way multiplexor on %s\n", 156 extra->name, i + 1, th[i + 1], num_ports, 157 port->name); 158 159 /* Analyse that port too. We won't recurse 160 forever because of the 'port->muxport < 0' 161 test above. */ 162 parport_daisy_init(extra); 163 } 164 } 165 166 if (port->muxport >= 0) 167 select_port(port); 168 169 parport_daisy_deselect_all(port); 170 detected += assign_addrs(port); 171 172 /* Count the potential legacy device at the end. */ 173 add_dev(numdevs++, port, -1); 174 175 /* Find out the legacy device's IEEE 1284 device ID. */ 176 deviceid = kmalloc(1024, GFP_KERNEL); 177 if (deviceid) { 178 if (parport_device_id(numdevs - 1, deviceid, 1024) > 2) 179 detected++; 180 181 kfree(deviceid); 182 } 183 184 if (!detected && !last_try) { 185 /* No devices were detected. Perhaps they are in some 186 funny state; let's try to reset them and see if 187 they wake up. */ 188 parport_daisy_fini(port); 189 parport_write_control(port, PARPORT_CONTROL_SELECT); 190 udelay(50); 191 parport_write_control(port, 192 PARPORT_CONTROL_SELECT | 193 PARPORT_CONTROL_INIT); 194 udelay(50); 195 last_try = 1; 196 goto again; 197 } 198 199 return detected; 200 } 201 202 /* Forget about devices on a physical port. */ 203 void parport_daisy_fini(struct parport *port) 204 { 205 struct daisydev **p; 206 207 spin_lock(&topology_lock); 208 p = &topology; 209 while (*p) { 210 struct daisydev *dev = *p; 211 if (dev->port != port) { 212 p = &dev->next; 213 continue; 214 } 215 *p = dev->next; 216 kfree(dev); 217 } 218 219 /* Gaps in the numbering could be handled better. How should 220 someone enumerate through all IEEE1284.3 devices in the 221 topology?. */ 222 if (!topology) numdevs = 0; 223 spin_unlock(&topology_lock); 224 return; 225 } 226 227 /** 228 * parport_open - find a device by canonical device number 229 * @devnum: canonical device number 230 * @name: name to associate with the device 231 * 232 * This function is similar to parport_register_device(), except 233 * that it locates a device by its number rather than by the port 234 * it is attached to. 235 * 236 * All parameters except for @devnum are the same as for 237 * parport_register_device(). The return value is the same as 238 * for parport_register_device(). 239 **/ 240 241 struct pardevice *parport_open(int devnum, const char *name) 242 { 243 struct daisydev *p = topology; 244 struct pardev_cb par_cb; 245 struct parport *port; 246 struct pardevice *dev; 247 int daisy; 248 249 memset(&par_cb, 0, sizeof(par_cb)); 250 spin_lock(&topology_lock); 251 while (p && p->devnum != devnum) 252 p = p->next; 253 254 if (!p) { 255 spin_unlock(&topology_lock); 256 return NULL; 257 } 258 259 daisy = p->daisy; 260 port = parport_get_port(p->port); 261 spin_unlock(&topology_lock); 262 263 dev = parport_register_dev_model(port, name, &par_cb, devnum); 264 parport_put_port(port); 265 if (!dev) 266 return NULL; 267 268 dev->daisy = daisy; 269 270 /* Check that there really is a device to select. */ 271 if (daisy >= 0) { 272 int selected; 273 parport_claim_or_block(dev); 274 selected = port->daisy; 275 parport_release(dev); 276 277 if (selected != daisy) { 278 /* No corresponding device. */ 279 parport_unregister_device(dev); 280 return NULL; 281 } 282 } 283 284 return dev; 285 } 286 287 /** 288 * parport_close - close a device opened with parport_open() 289 * @dev: device to close 290 * 291 * This is to parport_open() as parport_unregister_device() is to 292 * parport_register_device(). 293 **/ 294 295 void parport_close(struct pardevice *dev) 296 { 297 parport_unregister_device(dev); 298 } 299 300 /* Send a daisy-chain-style CPP command packet. */ 301 static int cpp_daisy(struct parport *port, int cmd) 302 { 303 unsigned char s; 304 305 parport_data_forward(port); 306 parport_write_data(port, 0xaa); udelay(2); 307 parport_write_data(port, 0x55); udelay(2); 308 parport_write_data(port, 0x00); udelay(2); 309 parport_write_data(port, 0xff); udelay(2); 310 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 311 | PARPORT_STATUS_PAPEROUT 312 | PARPORT_STATUS_SELECT 313 | PARPORT_STATUS_ERROR); 314 if (s != (PARPORT_STATUS_BUSY 315 | PARPORT_STATUS_PAPEROUT 316 | PARPORT_STATUS_SELECT 317 | PARPORT_STATUS_ERROR)) { 318 pr_debug("%s: cpp_daisy: aa5500ff(%02x)\n", port->name, s); 319 return -ENXIO; 320 } 321 322 parport_write_data(port, 0x87); udelay(2); 323 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 324 | PARPORT_STATUS_PAPEROUT 325 | PARPORT_STATUS_SELECT 326 | PARPORT_STATUS_ERROR); 327 if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) { 328 pr_debug("%s: cpp_daisy: aa5500ff87(%02x)\n", port->name, s); 329 return -ENXIO; 330 } 331 332 parport_write_data(port, 0x78); udelay(2); 333 parport_write_data(port, cmd); udelay(2); 334 parport_frob_control(port, 335 PARPORT_CONTROL_STROBE, 336 PARPORT_CONTROL_STROBE); 337 udelay(1); 338 s = parport_read_status(port); 339 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0); 340 udelay(1); 341 parport_write_data(port, 0xff); udelay(2); 342 343 return s; 344 } 345 346 /* Send a mux-style CPP command packet. */ 347 static int cpp_mux(struct parport *port, int cmd) 348 { 349 unsigned char s; 350 int rc; 351 352 parport_data_forward(port); 353 parport_write_data(port, 0xaa); udelay(2); 354 parport_write_data(port, 0x55); udelay(2); 355 parport_write_data(port, 0xf0); udelay(2); 356 parport_write_data(port, 0x0f); udelay(2); 357 parport_write_data(port, 0x52); udelay(2); 358 parport_write_data(port, 0xad); udelay(2); 359 parport_write_data(port, cmd); udelay(2); 360 361 s = parport_read_status(port); 362 if (!(s & PARPORT_STATUS_ACK)) { 363 pr_debug("%s: cpp_mux: aa55f00f52ad%02x(%02x)\n", 364 port->name, cmd, s); 365 return -EIO; 366 } 367 368 rc = (((s & PARPORT_STATUS_SELECT ? 1 : 0) << 0) | 369 ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) | 370 ((s & PARPORT_STATUS_BUSY ? 0 : 1) << 2) | 371 ((s & PARPORT_STATUS_ERROR ? 0 : 1) << 3)); 372 373 return rc; 374 } 375 376 void parport_daisy_deselect_all(struct parport *port) 377 { 378 cpp_daisy(port, 0x30); 379 } 380 381 int parport_daisy_select(struct parport *port, int daisy, int mode) 382 { 383 switch (mode) 384 { 385 // For these modes we should switch to EPP mode: 386 case IEEE1284_MODE_EPP: 387 case IEEE1284_MODE_EPPSL: 388 case IEEE1284_MODE_EPPSWE: 389 return !(cpp_daisy(port, 0x20 + daisy) & 390 PARPORT_STATUS_ERROR); 391 392 // For these modes we should switch to ECP mode: 393 case IEEE1284_MODE_ECP: 394 case IEEE1284_MODE_ECPRLE: 395 case IEEE1284_MODE_ECPSWE: 396 return !(cpp_daisy(port, 0xd0 + daisy) & 397 PARPORT_STATUS_ERROR); 398 399 // Nothing was told for BECP in Daisy chain specification. 400 // May be it's wise to use ECP? 401 case IEEE1284_MODE_BECP: 402 // Others use compat mode 403 case IEEE1284_MODE_NIBBLE: 404 case IEEE1284_MODE_BYTE: 405 case IEEE1284_MODE_COMPAT: 406 default: 407 return !(cpp_daisy(port, 0xe0 + daisy) & 408 PARPORT_STATUS_ERROR); 409 } 410 } 411 412 static int mux_present(struct parport *port) 413 { 414 return cpp_mux(port, 0x51) == 3; 415 } 416 417 static int num_mux_ports(struct parport *port) 418 { 419 return cpp_mux(port, 0x58); 420 } 421 422 static int select_port(struct parport *port) 423 { 424 int muxport = port->muxport; 425 return cpp_mux(port, 0x60 + muxport) == muxport; 426 } 427 428 static int assign_addrs(struct parport *port) 429 { 430 unsigned char s; 431 unsigned char daisy; 432 int thisdev = numdevs; 433 int detected; 434 char *deviceid; 435 436 parport_data_forward(port); 437 parport_write_data(port, 0xaa); udelay(2); 438 parport_write_data(port, 0x55); udelay(2); 439 parport_write_data(port, 0x00); udelay(2); 440 parport_write_data(port, 0xff); udelay(2); 441 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 442 | PARPORT_STATUS_PAPEROUT 443 | PARPORT_STATUS_SELECT 444 | PARPORT_STATUS_ERROR); 445 if (s != (PARPORT_STATUS_BUSY 446 | PARPORT_STATUS_PAPEROUT 447 | PARPORT_STATUS_SELECT 448 | PARPORT_STATUS_ERROR)) { 449 pr_debug("%s: assign_addrs: aa5500ff(%02x)\n", port->name, s); 450 return 0; 451 } 452 453 parport_write_data(port, 0x87); udelay(2); 454 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 455 | PARPORT_STATUS_PAPEROUT 456 | PARPORT_STATUS_SELECT 457 | PARPORT_STATUS_ERROR); 458 if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) { 459 pr_debug("%s: assign_addrs: aa5500ff87(%02x)\n", port->name, s); 460 return 0; 461 } 462 463 parport_write_data(port, 0x78); udelay(2); 464 s = parport_read_status(port); 465 466 for (daisy = 0; 467 (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)) 468 == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT) 469 && daisy < 4; 470 ++daisy) { 471 parport_write_data(port, daisy); 472 udelay(2); 473 parport_frob_control(port, 474 PARPORT_CONTROL_STROBE, 475 PARPORT_CONTROL_STROBE); 476 udelay(1); 477 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0); 478 udelay(1); 479 480 add_dev(numdevs++, port, daisy); 481 482 /* See if this device thought it was the last in the 483 * chain. */ 484 if (!(s & PARPORT_STATUS_BUSY)) 485 break; 486 487 /* We are seeing pass through status now. We see 488 last_dev from next device or if last_dev does not 489 work status lines from some non-daisy chain 490 device. */ 491 s = parport_read_status(port); 492 } 493 494 parport_write_data(port, 0xff); udelay(2); 495 detected = numdevs - thisdev; 496 pr_debug("%s: Found %d daisy-chained devices\n", port->name, detected); 497 498 /* Ask the new devices to introduce themselves. */ 499 deviceid = kmalloc(1024, GFP_KERNEL); 500 if (!deviceid) return 0; 501 502 for (daisy = 0; thisdev < numdevs; thisdev++, daisy++) 503 parport_device_id(thisdev, deviceid, 1024); 504 505 kfree(deviceid); 506 return detected; 507 } 508