1 /* 2 * Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved. 3 * Copyright (C) 2005, 06 Ralf Baechle (ralf@linux-mips.org) 4 * 5 * This program is free software; you can distribute it and/or modify it 6 * under the terms of the GNU General Public License (Version 2) as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * for more details. 13 * 14 * You should have received a copy of the GNU General Public License along 15 * with this program; if not, write to the Free Software Foundation, Inc., 16 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. 17 * 18 */ 19 20 #include <linux/device.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/fs.h> 24 #include <linux/init.h> 25 #include <asm/uaccess.h> 26 #include <linux/list.h> 27 #include <linux/vmalloc.h> 28 #include <linux/elf.h> 29 #include <linux/seq_file.h> 30 #include <linux/syscalls.h> 31 #include <linux/moduleloader.h> 32 #include <linux/interrupt.h> 33 #include <linux/poll.h> 34 #include <linux/sched.h> 35 #include <linux/wait.h> 36 #include <asm/mipsmtregs.h> 37 #include <asm/mips_mt.h> 38 #include <asm/cacheflush.h> 39 #include <linux/atomic.h> 40 #include <asm/cpu.h> 41 #include <asm/processor.h> 42 #include <asm/system.h> 43 #include <asm/vpe.h> 44 #include <asm/rtlx.h> 45 46 static struct rtlx_info *rtlx; 47 static int major; 48 static char module_name[] = "rtlx"; 49 50 static struct chan_waitqueues { 51 wait_queue_head_t rt_queue; 52 wait_queue_head_t lx_queue; 53 atomic_t in_open; 54 struct mutex mutex; 55 } channel_wqs[RTLX_CHANNELS]; 56 57 static struct vpe_notifications notify; 58 static int sp_stopping; 59 60 extern void *vpe_get_shared(int index); 61 62 static void rtlx_dispatch(void) 63 { 64 do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ); 65 } 66 67 68 /* Interrupt handler may be called before rtlx_init has otherwise had 69 a chance to run. 70 */ 71 static irqreturn_t rtlx_interrupt(int irq, void *dev_id) 72 { 73 unsigned int vpeflags; 74 unsigned long flags; 75 int i; 76 77 /* Ought not to be strictly necessary for SMTC builds */ 78 local_irq_save(flags); 79 vpeflags = dvpe(); 80 set_c0_status(0x100 << MIPS_CPU_RTLX_IRQ); 81 irq_enable_hazard(); 82 evpe(vpeflags); 83 local_irq_restore(flags); 84 85 for (i = 0; i < RTLX_CHANNELS; i++) { 86 wake_up(&channel_wqs[i].lx_queue); 87 wake_up(&channel_wqs[i].rt_queue); 88 } 89 90 return IRQ_HANDLED; 91 } 92 93 static void __used dump_rtlx(void) 94 { 95 int i; 96 97 printk("id 0x%lx state %d\n", rtlx->id, rtlx->state); 98 99 for (i = 0; i < RTLX_CHANNELS; i++) { 100 struct rtlx_channel *chan = &rtlx->channel[i]; 101 102 printk(" rt_state %d lx_state %d buffer_size %d\n", 103 chan->rt_state, chan->lx_state, chan->buffer_size); 104 105 printk(" rt_read %d rt_write %d\n", 106 chan->rt_read, chan->rt_write); 107 108 printk(" lx_read %d lx_write %d\n", 109 chan->lx_read, chan->lx_write); 110 111 printk(" rt_buffer <%s>\n", chan->rt_buffer); 112 printk(" lx_buffer <%s>\n", chan->lx_buffer); 113 } 114 } 115 116 /* call when we have the address of the shared structure from the SP side. */ 117 static int rtlx_init(struct rtlx_info *rtlxi) 118 { 119 if (rtlxi->id != RTLX_ID) { 120 printk(KERN_ERR "no valid RTLX id at 0x%p 0x%lx\n", 121 rtlxi, rtlxi->id); 122 return -ENOEXEC; 123 } 124 125 rtlx = rtlxi; 126 127 return 0; 128 } 129 130 /* notifications */ 131 static void starting(int vpe) 132 { 133 int i; 134 sp_stopping = 0; 135 136 /* force a reload of rtlx */ 137 rtlx=NULL; 138 139 /* wake up any sleeping rtlx_open's */ 140 for (i = 0; i < RTLX_CHANNELS; i++) 141 wake_up_interruptible(&channel_wqs[i].lx_queue); 142 } 143 144 static void stopping(int vpe) 145 { 146 int i; 147 148 sp_stopping = 1; 149 for (i = 0; i < RTLX_CHANNELS; i++) 150 wake_up_interruptible(&channel_wqs[i].lx_queue); 151 } 152 153 154 int rtlx_open(int index, int can_sleep) 155 { 156 struct rtlx_info **p; 157 struct rtlx_channel *chan; 158 enum rtlx_state state; 159 int ret = 0; 160 161 if (index >= RTLX_CHANNELS) { 162 printk(KERN_DEBUG "rtlx_open index out of range\n"); 163 return -ENOSYS; 164 } 165 166 if (atomic_inc_return(&channel_wqs[index].in_open) > 1) { 167 printk(KERN_DEBUG "rtlx_open channel %d already opened\n", 168 index); 169 ret = -EBUSY; 170 goto out_fail; 171 } 172 173 if (rtlx == NULL) { 174 if( (p = vpe_get_shared(tclimit)) == NULL) { 175 if (can_sleep) { 176 __wait_event_interruptible(channel_wqs[index].lx_queue, 177 (p = vpe_get_shared(tclimit)), ret); 178 if (ret) 179 goto out_fail; 180 } else { 181 printk(KERN_DEBUG "No SP program loaded, and device " 182 "opened with O_NONBLOCK\n"); 183 ret = -ENOSYS; 184 goto out_fail; 185 } 186 } 187 188 smp_rmb(); 189 if (*p == NULL) { 190 if (can_sleep) { 191 DEFINE_WAIT(wait); 192 193 for (;;) { 194 prepare_to_wait( 195 &channel_wqs[index].lx_queue, 196 &wait, TASK_INTERRUPTIBLE); 197 smp_rmb(); 198 if (*p != NULL) 199 break; 200 if (!signal_pending(current)) { 201 schedule(); 202 continue; 203 } 204 ret = -ERESTARTSYS; 205 goto out_fail; 206 } 207 finish_wait(&channel_wqs[index].lx_queue, &wait); 208 } else { 209 pr_err(" *vpe_get_shared is NULL. " 210 "Has an SP program been loaded?\n"); 211 ret = -ENOSYS; 212 goto out_fail; 213 } 214 } 215 216 if ((unsigned int)*p < KSEG0) { 217 printk(KERN_WARNING "vpe_get_shared returned an " 218 "invalid pointer maybe an error code %d\n", 219 (int)*p); 220 ret = -ENOSYS; 221 goto out_fail; 222 } 223 224 if ((ret = rtlx_init(*p)) < 0) 225 goto out_ret; 226 } 227 228 chan = &rtlx->channel[index]; 229 230 state = xchg(&chan->lx_state, RTLX_STATE_OPENED); 231 if (state == RTLX_STATE_OPENED) { 232 ret = -EBUSY; 233 goto out_fail; 234 } 235 236 out_fail: 237 smp_mb(); 238 atomic_dec(&channel_wqs[index].in_open); 239 smp_mb(); 240 241 out_ret: 242 return ret; 243 } 244 245 int rtlx_release(int index) 246 { 247 if (rtlx == NULL) { 248 pr_err("rtlx_release() with null rtlx\n"); 249 return 0; 250 } 251 rtlx->channel[index].lx_state = RTLX_STATE_UNUSED; 252 return 0; 253 } 254 255 unsigned int rtlx_read_poll(int index, int can_sleep) 256 { 257 struct rtlx_channel *chan; 258 259 if (rtlx == NULL) 260 return 0; 261 262 chan = &rtlx->channel[index]; 263 264 /* data available to read? */ 265 if (chan->lx_read == chan->lx_write) { 266 if (can_sleep) { 267 int ret = 0; 268 269 __wait_event_interruptible(channel_wqs[index].lx_queue, 270 (chan->lx_read != chan->lx_write) || 271 sp_stopping, ret); 272 if (ret) 273 return ret; 274 275 if (sp_stopping) 276 return 0; 277 } else 278 return 0; 279 } 280 281 return (chan->lx_write + chan->buffer_size - chan->lx_read) 282 % chan->buffer_size; 283 } 284 285 static inline int write_spacefree(int read, int write, int size) 286 { 287 if (read == write) { 288 /* 289 * Never fill the buffer completely, so indexes are always 290 * equal if empty and only empty, or !equal if data available 291 */ 292 return size - 1; 293 } 294 295 return ((read + size - write) % size) - 1; 296 } 297 298 unsigned int rtlx_write_poll(int index) 299 { 300 struct rtlx_channel *chan = &rtlx->channel[index]; 301 302 return write_spacefree(chan->rt_read, chan->rt_write, 303 chan->buffer_size); 304 } 305 306 ssize_t rtlx_read(int index, void __user *buff, size_t count) 307 { 308 size_t lx_write, fl = 0L; 309 struct rtlx_channel *lx; 310 unsigned long failed; 311 312 if (rtlx == NULL) 313 return -ENOSYS; 314 315 lx = &rtlx->channel[index]; 316 317 mutex_lock(&channel_wqs[index].mutex); 318 smp_rmb(); 319 lx_write = lx->lx_write; 320 321 /* find out how much in total */ 322 count = min(count, 323 (size_t)(lx_write + lx->buffer_size - lx->lx_read) 324 % lx->buffer_size); 325 326 /* then how much from the read pointer onwards */ 327 fl = min(count, (size_t)lx->buffer_size - lx->lx_read); 328 329 failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl); 330 if (failed) 331 goto out; 332 333 /* and if there is anything left at the beginning of the buffer */ 334 if (count - fl) 335 failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl); 336 337 out: 338 count -= failed; 339 340 smp_wmb(); 341 lx->lx_read = (lx->lx_read + count) % lx->buffer_size; 342 smp_wmb(); 343 mutex_unlock(&channel_wqs[index].mutex); 344 345 return count; 346 } 347 348 ssize_t rtlx_write(int index, const void __user *buffer, size_t count) 349 { 350 struct rtlx_channel *rt; 351 unsigned long failed; 352 size_t rt_read; 353 size_t fl; 354 355 if (rtlx == NULL) 356 return(-ENOSYS); 357 358 rt = &rtlx->channel[index]; 359 360 mutex_lock(&channel_wqs[index].mutex); 361 smp_rmb(); 362 rt_read = rt->rt_read; 363 364 /* total number of bytes to copy */ 365 count = min(count, (size_t)write_spacefree(rt_read, rt->rt_write, 366 rt->buffer_size)); 367 368 /* first bit from write pointer to the end of the buffer, or count */ 369 fl = min(count, (size_t) rt->buffer_size - rt->rt_write); 370 371 failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl); 372 if (failed) 373 goto out; 374 375 /* if there's any left copy to the beginning of the buffer */ 376 if (count - fl) { 377 failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl); 378 } 379 380 out: 381 count -= failed; 382 383 smp_wmb(); 384 rt->rt_write = (rt->rt_write + count) % rt->buffer_size; 385 smp_wmb(); 386 mutex_unlock(&channel_wqs[index].mutex); 387 388 return count; 389 } 390 391 392 static int file_open(struct inode *inode, struct file *filp) 393 { 394 return rtlx_open(iminor(inode), (filp->f_flags & O_NONBLOCK) ? 0 : 1); 395 } 396 397 static int file_release(struct inode *inode, struct file *filp) 398 { 399 return rtlx_release(iminor(inode)); 400 } 401 402 static unsigned int file_poll(struct file *file, poll_table * wait) 403 { 404 int minor; 405 unsigned int mask = 0; 406 407 minor = iminor(file->f_path.dentry->d_inode); 408 409 poll_wait(file, &channel_wqs[minor].rt_queue, wait); 410 poll_wait(file, &channel_wqs[minor].lx_queue, wait); 411 412 if (rtlx == NULL) 413 return 0; 414 415 /* data available to read? */ 416 if (rtlx_read_poll(minor, 0)) 417 mask |= POLLIN | POLLRDNORM; 418 419 /* space to write */ 420 if (rtlx_write_poll(minor)) 421 mask |= POLLOUT | POLLWRNORM; 422 423 return mask; 424 } 425 426 static ssize_t file_read(struct file *file, char __user * buffer, size_t count, 427 loff_t * ppos) 428 { 429 int minor = iminor(file->f_path.dentry->d_inode); 430 431 /* data available? */ 432 if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) { 433 return 0; // -EAGAIN makes cat whinge 434 } 435 436 return rtlx_read(minor, buffer, count); 437 } 438 439 static ssize_t file_write(struct file *file, const char __user * buffer, 440 size_t count, loff_t * ppos) 441 { 442 int minor; 443 struct rtlx_channel *rt; 444 445 minor = iminor(file->f_path.dentry->d_inode); 446 rt = &rtlx->channel[minor]; 447 448 /* any space left... */ 449 if (!rtlx_write_poll(minor)) { 450 int ret = 0; 451 452 if (file->f_flags & O_NONBLOCK) 453 return -EAGAIN; 454 455 __wait_event_interruptible(channel_wqs[minor].rt_queue, 456 rtlx_write_poll(minor), 457 ret); 458 if (ret) 459 return ret; 460 } 461 462 return rtlx_write(minor, buffer, count); 463 } 464 465 static const struct file_operations rtlx_fops = { 466 .owner = THIS_MODULE, 467 .open = file_open, 468 .release = file_release, 469 .write = file_write, 470 .read = file_read, 471 .poll = file_poll, 472 .llseek = noop_llseek, 473 }; 474 475 static struct irqaction rtlx_irq = { 476 .handler = rtlx_interrupt, 477 .flags = IRQF_DISABLED, 478 .name = "RTLX", 479 }; 480 481 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ; 482 483 static char register_chrdev_failed[] __initdata = 484 KERN_ERR "rtlx_module_init: unable to register device\n"; 485 486 static int __init rtlx_module_init(void) 487 { 488 struct device *dev; 489 int i, err; 490 491 if (!cpu_has_mipsmt) { 492 printk("VPE loader: not a MIPS MT capable processor\n"); 493 return -ENODEV; 494 } 495 496 if (tclimit == 0) { 497 printk(KERN_WARNING "No TCs reserved for AP/SP, not " 498 "initializing RTLX.\nPass maxtcs=<n> argument as kernel " 499 "argument\n"); 500 501 return -ENODEV; 502 } 503 504 major = register_chrdev(0, module_name, &rtlx_fops); 505 if (major < 0) { 506 printk(register_chrdev_failed); 507 return major; 508 } 509 510 /* initialise the wait queues */ 511 for (i = 0; i < RTLX_CHANNELS; i++) { 512 init_waitqueue_head(&channel_wqs[i].rt_queue); 513 init_waitqueue_head(&channel_wqs[i].lx_queue); 514 atomic_set(&channel_wqs[i].in_open, 0); 515 mutex_init(&channel_wqs[i].mutex); 516 517 dev = device_create(mt_class, NULL, MKDEV(major, i), NULL, 518 "%s%d", module_name, i); 519 if (IS_ERR(dev)) { 520 err = PTR_ERR(dev); 521 goto out_chrdev; 522 } 523 } 524 525 /* set up notifiers */ 526 notify.start = starting; 527 notify.stop = stopping; 528 vpe_notify(tclimit, ¬ify); 529 530 if (cpu_has_vint) 531 set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch); 532 else { 533 pr_err("APRP RTLX init on non-vectored-interrupt processor\n"); 534 err = -ENODEV; 535 goto out_chrdev; 536 } 537 538 rtlx_irq.dev_id = rtlx; 539 setup_irq(rtlx_irq_num, &rtlx_irq); 540 541 return 0; 542 543 out_chrdev: 544 for (i = 0; i < RTLX_CHANNELS; i++) 545 device_destroy(mt_class, MKDEV(major, i)); 546 547 return err; 548 } 549 550 static void __exit rtlx_module_exit(void) 551 { 552 int i; 553 554 for (i = 0; i < RTLX_CHANNELS; i++) 555 device_destroy(mt_class, MKDEV(major, i)); 556 557 unregister_chrdev(major, module_name); 558 } 559 560 module_init(rtlx_module_init); 561 module_exit(rtlx_module_exit); 562 563 MODULE_DESCRIPTION("MIPS RTLX"); 564 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc."); 565 MODULE_LICENSE("GPL"); 566