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 }; 101 102 /* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains. 103 * Return value is number of devices actually detected. */ 104 int parport_daisy_init(struct parport *port) 105 { 106 int detected = 0; 107 char *deviceid; 108 static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" }; 109 int num_ports; 110 int i; 111 int last_try = 0; 112 113 if (!daisy_init_done) { 114 /* 115 * flag should be marked true first as 116 * parport_register_driver() might try to load the low 117 * level driver which will lead to announcing new ports 118 * and which will again come back here at 119 * parport_daisy_init() 120 */ 121 daisy_init_done = true; 122 i = parport_register_driver(&daisy_driver); 123 if (i) { 124 pr_err("daisy registration failed\n"); 125 daisy_init_done = false; 126 return i; 127 } 128 } 129 130 again: 131 /* Because this is called before any other devices exist, 132 * we don't have to claim exclusive access. */ 133 134 /* If mux present on normal port, need to create new 135 * parports for each extra port. */ 136 if (port->muxport < 0 && mux_present(port) && 137 /* don't be fooled: a mux must have 2 or 4 ports. */ 138 ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) { 139 /* Leave original as port zero. */ 140 port->muxport = 0; 141 pr_info("%s: 1st (default) port of %d-way multiplexor\n", 142 port->name, num_ports); 143 for (i = 1; i < num_ports; i++) { 144 /* Clone the port. */ 145 struct parport *extra = clone_parport(port, i); 146 if (!extra) { 147 if (signal_pending(current)) 148 break; 149 150 schedule(); 151 continue; 152 } 153 154 pr_info("%s: %d%s port of %d-way multiplexor on %s\n", 155 extra->name, i + 1, th[i + 1], num_ports, 156 port->name); 157 158 /* Analyse that port too. We won't recurse 159 forever because of the 'port->muxport < 0' 160 test above. */ 161 parport_daisy_init(extra); 162 } 163 } 164 165 if (port->muxport >= 0) 166 select_port(port); 167 168 parport_daisy_deselect_all(port); 169 detected += assign_addrs(port); 170 171 /* Count the potential legacy device at the end. */ 172 add_dev(numdevs++, port, -1); 173 174 /* Find out the legacy device's IEEE 1284 device ID. */ 175 deviceid = kmalloc(1024, GFP_KERNEL); 176 if (deviceid) { 177 if (parport_device_id(numdevs - 1, deviceid, 1024) > 2) 178 detected++; 179 180 kfree(deviceid); 181 } 182 183 if (!detected && !last_try) { 184 /* No devices were detected. Perhaps they are in some 185 funny state; let's try to reset them and see if 186 they wake up. */ 187 parport_daisy_fini(port); 188 parport_write_control(port, PARPORT_CONTROL_SELECT); 189 udelay(50); 190 parport_write_control(port, 191 PARPORT_CONTROL_SELECT | 192 PARPORT_CONTROL_INIT); 193 udelay(50); 194 last_try = 1; 195 goto again; 196 } 197 198 return detected; 199 } 200 201 /* Forget about devices on a physical port. */ 202 void parport_daisy_fini(struct parport *port) 203 { 204 struct daisydev **p; 205 206 spin_lock(&topology_lock); 207 p = &topology; 208 while (*p) { 209 struct daisydev *dev = *p; 210 if (dev->port != port) { 211 p = &dev->next; 212 continue; 213 } 214 *p = dev->next; 215 kfree(dev); 216 } 217 218 /* Gaps in the numbering could be handled better. How should 219 someone enumerate through all IEEE1284.3 devices in the 220 topology?. */ 221 if (!topology) numdevs = 0; 222 spin_unlock(&topology_lock); 223 return; 224 } 225 226 /** 227 * parport_open - find a device by canonical device number 228 * @devnum: canonical device number 229 * @name: name to associate with the device 230 * 231 * This function is similar to parport_register_device(), except 232 * that it locates a device by its number rather than by the port 233 * it is attached to. 234 * 235 * All parameters except for @devnum are the same as for 236 * parport_register_device(). The return value is the same as 237 * for parport_register_device(). 238 **/ 239 240 struct pardevice *parport_open(int devnum, const char *name) 241 { 242 struct daisydev *p = topology; 243 struct pardev_cb par_cb; 244 struct parport *port; 245 struct pardevice *dev; 246 int daisy; 247 248 memset(&par_cb, 0, sizeof(par_cb)); 249 spin_lock(&topology_lock); 250 while (p && p->devnum != devnum) 251 p = p->next; 252 253 if (!p) { 254 spin_unlock(&topology_lock); 255 return NULL; 256 } 257 258 daisy = p->daisy; 259 port = parport_get_port(p->port); 260 spin_unlock(&topology_lock); 261 262 dev = parport_register_dev_model(port, name, &par_cb, devnum); 263 parport_put_port(port); 264 if (!dev) 265 return NULL; 266 267 dev->daisy = daisy; 268 269 /* Check that there really is a device to select. */ 270 if (daisy >= 0) { 271 int selected; 272 parport_claim_or_block(dev); 273 selected = port->daisy; 274 parport_release(dev); 275 276 if (selected != daisy) { 277 /* No corresponding device. */ 278 parport_unregister_device(dev); 279 return NULL; 280 } 281 } 282 283 return dev; 284 } 285 286 /** 287 * parport_close - close a device opened with parport_open() 288 * @dev: device to close 289 * 290 * This is to parport_open() as parport_unregister_device() is to 291 * parport_register_device(). 292 **/ 293 294 void parport_close(struct pardevice *dev) 295 { 296 parport_unregister_device(dev); 297 } 298 299 /* Send a daisy-chain-style CPP command packet. */ 300 static int cpp_daisy(struct parport *port, int cmd) 301 { 302 unsigned char s; 303 304 parport_data_forward(port); 305 parport_write_data(port, 0xaa); udelay(2); 306 parport_write_data(port, 0x55); udelay(2); 307 parport_write_data(port, 0x00); udelay(2); 308 parport_write_data(port, 0xff); udelay(2); 309 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 310 | PARPORT_STATUS_PAPEROUT 311 | PARPORT_STATUS_SELECT 312 | PARPORT_STATUS_ERROR); 313 if (s != (PARPORT_STATUS_BUSY 314 | PARPORT_STATUS_PAPEROUT 315 | PARPORT_STATUS_SELECT 316 | PARPORT_STATUS_ERROR)) { 317 pr_debug("%s: cpp_daisy: aa5500ff(%02x)\n", port->name, s); 318 return -ENXIO; 319 } 320 321 parport_write_data(port, 0x87); udelay(2); 322 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 323 | PARPORT_STATUS_PAPEROUT 324 | PARPORT_STATUS_SELECT 325 | PARPORT_STATUS_ERROR); 326 if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) { 327 pr_debug("%s: cpp_daisy: aa5500ff87(%02x)\n", port->name, s); 328 return -ENXIO; 329 } 330 331 parport_write_data(port, 0x78); udelay(2); 332 parport_write_data(port, cmd); udelay(2); 333 parport_frob_control(port, 334 PARPORT_CONTROL_STROBE, 335 PARPORT_CONTROL_STROBE); 336 udelay(1); 337 s = parport_read_status(port); 338 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0); 339 udelay(1); 340 parport_write_data(port, 0xff); udelay(2); 341 342 return s; 343 } 344 345 /* Send a mux-style CPP command packet. */ 346 static int cpp_mux(struct parport *port, int cmd) 347 { 348 unsigned char s; 349 int rc; 350 351 parport_data_forward(port); 352 parport_write_data(port, 0xaa); udelay(2); 353 parport_write_data(port, 0x55); udelay(2); 354 parport_write_data(port, 0xf0); udelay(2); 355 parport_write_data(port, 0x0f); udelay(2); 356 parport_write_data(port, 0x52); udelay(2); 357 parport_write_data(port, 0xad); udelay(2); 358 parport_write_data(port, cmd); udelay(2); 359 360 s = parport_read_status(port); 361 if (!(s & PARPORT_STATUS_ACK)) { 362 pr_debug("%s: cpp_mux: aa55f00f52ad%02x(%02x)\n", 363 port->name, cmd, s); 364 return -EIO; 365 } 366 367 rc = (((s & PARPORT_STATUS_SELECT ? 1 : 0) << 0) | 368 ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) | 369 ((s & PARPORT_STATUS_BUSY ? 0 : 1) << 2) | 370 ((s & PARPORT_STATUS_ERROR ? 0 : 1) << 3)); 371 372 return rc; 373 } 374 375 void parport_daisy_deselect_all(struct parport *port) 376 { 377 cpp_daisy(port, 0x30); 378 } 379 380 int parport_daisy_select(struct parport *port, int daisy, int mode) 381 { 382 switch (mode) 383 { 384 // For these modes we should switch to EPP mode: 385 case IEEE1284_MODE_EPP: 386 case IEEE1284_MODE_EPPSL: 387 case IEEE1284_MODE_EPPSWE: 388 return !(cpp_daisy(port, 0x20 + daisy) & 389 PARPORT_STATUS_ERROR); 390 391 // For these modes we should switch to ECP mode: 392 case IEEE1284_MODE_ECP: 393 case IEEE1284_MODE_ECPRLE: 394 case IEEE1284_MODE_ECPSWE: 395 return !(cpp_daisy(port, 0xd0 + daisy) & 396 PARPORT_STATUS_ERROR); 397 398 // Nothing was told for BECP in Daisy chain specification. 399 // May be it's wise to use ECP? 400 case IEEE1284_MODE_BECP: 401 // Others use compat mode 402 case IEEE1284_MODE_NIBBLE: 403 case IEEE1284_MODE_BYTE: 404 case IEEE1284_MODE_COMPAT: 405 default: 406 return !(cpp_daisy(port, 0xe0 + daisy) & 407 PARPORT_STATUS_ERROR); 408 } 409 } 410 411 static int mux_present(struct parport *port) 412 { 413 return cpp_mux(port, 0x51) == 3; 414 } 415 416 static int num_mux_ports(struct parport *port) 417 { 418 return cpp_mux(port, 0x58); 419 } 420 421 static int select_port(struct parport *port) 422 { 423 int muxport = port->muxport; 424 return cpp_mux(port, 0x60 + muxport) == muxport; 425 } 426 427 static int assign_addrs(struct parport *port) 428 { 429 unsigned char s; 430 unsigned char daisy; 431 int thisdev = numdevs; 432 int detected; 433 char *deviceid; 434 435 parport_data_forward(port); 436 parport_write_data(port, 0xaa); udelay(2); 437 parport_write_data(port, 0x55); udelay(2); 438 parport_write_data(port, 0x00); udelay(2); 439 parport_write_data(port, 0xff); udelay(2); 440 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 441 | PARPORT_STATUS_PAPEROUT 442 | PARPORT_STATUS_SELECT 443 | PARPORT_STATUS_ERROR); 444 if (s != (PARPORT_STATUS_BUSY 445 | PARPORT_STATUS_PAPEROUT 446 | PARPORT_STATUS_SELECT 447 | PARPORT_STATUS_ERROR)) { 448 pr_debug("%s: assign_addrs: aa5500ff(%02x)\n", port->name, s); 449 return 0; 450 } 451 452 parport_write_data(port, 0x87); udelay(2); 453 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 454 | PARPORT_STATUS_PAPEROUT 455 | PARPORT_STATUS_SELECT 456 | PARPORT_STATUS_ERROR); 457 if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) { 458 pr_debug("%s: assign_addrs: aa5500ff87(%02x)\n", port->name, s); 459 return 0; 460 } 461 462 parport_write_data(port, 0x78); udelay(2); 463 s = parport_read_status(port); 464 465 for (daisy = 0; 466 (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)) 467 == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT) 468 && daisy < 4; 469 ++daisy) { 470 parport_write_data(port, daisy); 471 udelay(2); 472 parport_frob_control(port, 473 PARPORT_CONTROL_STROBE, 474 PARPORT_CONTROL_STROBE); 475 udelay(1); 476 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0); 477 udelay(1); 478 479 add_dev(numdevs++, port, daisy); 480 481 /* See if this device thought it was the last in the 482 * chain. */ 483 if (!(s & PARPORT_STATUS_BUSY)) 484 break; 485 486 /* We are seeing pass through status now. We see 487 last_dev from next device or if last_dev does not 488 work status lines from some non-daisy chain 489 device. */ 490 s = parport_read_status(port); 491 } 492 493 parport_write_data(port, 0xff); udelay(2); 494 detected = numdevs - thisdev; 495 pr_debug("%s: Found %d daisy-chained devices\n", port->name, detected); 496 497 /* Ask the new devices to introduce themselves. */ 498 deviceid = kmalloc(1024, GFP_KERNEL); 499 if (!deviceid) return 0; 500 501 for (daisy = 0; thisdev < numdevs; thisdev++, daisy++) 502 parport_device_id(thisdev, deviceid, 1024); 503 504 kfree(deviceid); 505 return detected; 506 } 507