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/slab.h> 27 #include <linux/list.h> 28 #include <linux/vmalloc.h> 29 #include <linux/elf.h> 30 #include <linux/seq_file.h> 31 #include <linux/syscalls.h> 32 #include <linux/moduleloader.h> 33 #include <linux/interrupt.h> 34 #include <linux/poll.h> 35 #include <linux/sched.h> 36 #include <linux/wait.h> 37 #include <asm/mipsmtregs.h> 38 #include <asm/mips_mt.h> 39 #include <asm/cacheflush.h> 40 #include <asm/atomic.h> 41 #include <asm/cpu.h> 42 #include <asm/processor.h> 43 #include <asm/system.h> 44 #include <asm/vpe.h> 45 #include <asm/rtlx.h> 46 47 #define RTLX_TARG_VPE 1 48 49 static struct rtlx_info *rtlx; 50 static int major; 51 static char module_name[] = "rtlx"; 52 53 static struct chan_waitqueues { 54 wait_queue_head_t rt_queue; 55 wait_queue_head_t lx_queue; 56 atomic_t in_open; 57 } channel_wqs[RTLX_CHANNELS]; 58 59 static struct irqaction irq; 60 static int irq_num; 61 static struct vpe_notifications notify; 62 static int sp_stopping = 0; 63 64 extern void *vpe_get_shared(int index); 65 66 static void rtlx_dispatch(void) 67 { 68 do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ); 69 } 70 71 72 /* Interrupt handler may be called before rtlx_init has otherwise had 73 a chance to run. 74 */ 75 static irqreturn_t rtlx_interrupt(int irq, void *dev_id) 76 { 77 int i; 78 79 for (i = 0; i < RTLX_CHANNELS; i++) { 80 wake_up(&channel_wqs[i].lx_queue); 81 wake_up(&channel_wqs[i].rt_queue); 82 } 83 84 return IRQ_HANDLED; 85 } 86 87 static __attribute_used__ void dump_rtlx(void) 88 { 89 int i; 90 91 printk("id 0x%lx state %d\n", rtlx->id, rtlx->state); 92 93 for (i = 0; i < RTLX_CHANNELS; i++) { 94 struct rtlx_channel *chan = &rtlx->channel[i]; 95 96 printk(" rt_state %d lx_state %d buffer_size %d\n", 97 chan->rt_state, chan->lx_state, chan->buffer_size); 98 99 printk(" rt_read %d rt_write %d\n", 100 chan->rt_read, chan->rt_write); 101 102 printk(" lx_read %d lx_write %d\n", 103 chan->lx_read, chan->lx_write); 104 105 printk(" rt_buffer <%s>\n", chan->rt_buffer); 106 printk(" lx_buffer <%s>\n", chan->lx_buffer); 107 } 108 } 109 110 /* call when we have the address of the shared structure from the SP side. */ 111 static int rtlx_init(struct rtlx_info *rtlxi) 112 { 113 if (rtlxi->id != RTLX_ID) { 114 printk(KERN_ERR "no valid RTLX id at 0x%p 0x%x\n", rtlxi, rtlxi->id); 115 return -ENOEXEC; 116 } 117 118 rtlx = rtlxi; 119 120 return 0; 121 } 122 123 /* notifications */ 124 static void starting(int vpe) 125 { 126 int i; 127 sp_stopping = 0; 128 129 /* force a reload of rtlx */ 130 rtlx=NULL; 131 132 /* wake up any sleeping rtlx_open's */ 133 for (i = 0; i < RTLX_CHANNELS; i++) 134 wake_up_interruptible(&channel_wqs[i].lx_queue); 135 } 136 137 static void stopping(int vpe) 138 { 139 int i; 140 141 sp_stopping = 1; 142 for (i = 0; i < RTLX_CHANNELS; i++) 143 wake_up_interruptible(&channel_wqs[i].lx_queue); 144 } 145 146 147 int rtlx_open(int index, int can_sleep) 148 { 149 volatile struct rtlx_info **p; 150 struct rtlx_channel *chan; 151 enum rtlx_state state; 152 int ret = 0; 153 154 if (index >= RTLX_CHANNELS) { 155 printk(KERN_DEBUG "rtlx_open index out of range\n"); 156 return -ENOSYS; 157 } 158 159 if (atomic_inc_return(&channel_wqs[index].in_open) > 1) { 160 printk(KERN_DEBUG "rtlx_open channel %d already opened\n", 161 index); 162 ret = -EBUSY; 163 goto out_fail; 164 } 165 166 if (rtlx == NULL) { 167 if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) { 168 if (can_sleep) { 169 __wait_event_interruptible(channel_wqs[index].lx_queue, 170 (p = vpe_get_shared(RTLX_TARG_VPE)), 171 ret); 172 if (ret) 173 goto out_fail; 174 } else { 175 printk(KERN_DEBUG "No SP program loaded, and device " 176 "opened with O_NONBLOCK\n"); 177 ret = -ENOSYS; 178 goto out_fail; 179 } 180 } 181 182 if (*p == NULL) { 183 if (can_sleep) { 184 __wait_event_interruptible(channel_wqs[index].lx_queue, 185 *p != NULL, 186 ret); 187 if (ret) 188 goto out_fail; 189 } else { 190 printk(" *vpe_get_shared is NULL. " 191 "Has an SP program been loaded?\n"); 192 ret = -ENOSYS; 193 goto out_fail; 194 } 195 } 196 197 if ((unsigned int)*p < KSEG0) { 198 printk(KERN_WARNING "vpe_get_shared returned an invalid pointer " 199 "maybe an error code %d\n", (int)*p); 200 ret = -ENOSYS; 201 goto out_fail; 202 } 203 204 if ((ret = rtlx_init(*p)) < 0) 205 goto out_ret; 206 } 207 208 chan = &rtlx->channel[index]; 209 210 state = xchg(&chan->lx_state, RTLX_STATE_OPENED); 211 if (state == RTLX_STATE_OPENED) { 212 ret = -EBUSY; 213 goto out_fail; 214 } 215 216 out_fail: 217 smp_mb(); 218 atomic_dec(&channel_wqs[index].in_open); 219 smp_mb(); 220 221 out_ret: 222 return ret; 223 } 224 225 int rtlx_release(int index) 226 { 227 rtlx->channel[index].lx_state = RTLX_STATE_UNUSED; 228 return 0; 229 } 230 231 unsigned int rtlx_read_poll(int index, int can_sleep) 232 { 233 struct rtlx_channel *chan; 234 235 if (rtlx == NULL) 236 return 0; 237 238 chan = &rtlx->channel[index]; 239 240 /* data available to read? */ 241 if (chan->lx_read == chan->lx_write) { 242 if (can_sleep) { 243 int ret = 0; 244 245 __wait_event_interruptible(channel_wqs[index].lx_queue, 246 chan->lx_read != chan->lx_write || sp_stopping, 247 ret); 248 if (ret) 249 return ret; 250 251 if (sp_stopping) 252 return 0; 253 } else 254 return 0; 255 } 256 257 return (chan->lx_write + chan->buffer_size - chan->lx_read) 258 % chan->buffer_size; 259 } 260 261 static inline int write_spacefree(int read, int write, int size) 262 { 263 if (read == write) { 264 /* 265 * Never fill the buffer completely, so indexes are always 266 * equal if empty and only empty, or !equal if data available 267 */ 268 return size - 1; 269 } 270 271 return ((read + size - write) % size) - 1; 272 } 273 274 unsigned int rtlx_write_poll(int index) 275 { 276 struct rtlx_channel *chan = &rtlx->channel[index]; 277 return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size); 278 } 279 280 static inline void copy_to(void *dst, void *src, size_t count, int user) 281 { 282 if (user) 283 copy_to_user(dst, src, count); 284 else 285 memcpy(dst, src, count); 286 } 287 288 static inline void copy_from(void *dst, void *src, size_t count, int user) 289 { 290 if (user) 291 copy_from_user(dst, src, count); 292 else 293 memcpy(dst, src, count); 294 } 295 296 ssize_t rtlx_read(int index, void *buff, size_t count, int user) 297 { 298 size_t fl = 0L; 299 struct rtlx_channel *lx; 300 301 if (rtlx == NULL) 302 return -ENOSYS; 303 304 lx = &rtlx->channel[index]; 305 306 /* find out how much in total */ 307 count = min(count, 308 (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read) 309 % lx->buffer_size); 310 311 /* then how much from the read pointer onwards */ 312 fl = min( count, (size_t)lx->buffer_size - lx->lx_read); 313 314 copy_to(buff, &lx->lx_buffer[lx->lx_read], fl, user); 315 316 /* and if there is anything left at the beginning of the buffer */ 317 if ( count - fl ) 318 copy_to (buff + fl, lx->lx_buffer, count - fl, user); 319 320 /* update the index */ 321 lx->lx_read += count; 322 lx->lx_read %= lx->buffer_size; 323 324 return count; 325 } 326 327 ssize_t rtlx_write(int index, void *buffer, size_t count, int user) 328 { 329 struct rtlx_channel *rt; 330 size_t fl; 331 332 if (rtlx == NULL) 333 return(-ENOSYS); 334 335 rt = &rtlx->channel[index]; 336 337 /* total number of bytes to copy */ 338 count = min(count, 339 (size_t)write_spacefree(rt->rt_read, rt->rt_write, 340 rt->buffer_size)); 341 342 /* first bit from write pointer to the end of the buffer, or count */ 343 fl = min(count, (size_t) rt->buffer_size - rt->rt_write); 344 345 copy_from (&rt->rt_buffer[rt->rt_write], buffer, fl, user); 346 347 /* if there's any left copy to the beginning of the buffer */ 348 if( count - fl ) 349 copy_from (rt->rt_buffer, buffer + fl, count - fl, user); 350 351 rt->rt_write += count; 352 rt->rt_write %= rt->buffer_size; 353 354 return(count); 355 } 356 357 358 static int file_open(struct inode *inode, struct file *filp) 359 { 360 int minor = iminor(inode); 361 362 return rtlx_open(minor, (filp->f_flags & O_NONBLOCK) ? 0 : 1); 363 } 364 365 static int file_release(struct inode *inode, struct file *filp) 366 { 367 int minor = iminor(inode); 368 369 return rtlx_release(minor); 370 } 371 372 static unsigned int file_poll(struct file *file, poll_table * wait) 373 { 374 int minor; 375 unsigned int mask = 0; 376 377 minor = iminor(file->f_path.dentry->d_inode); 378 379 poll_wait(file, &channel_wqs[minor].rt_queue, wait); 380 poll_wait(file, &channel_wqs[minor].lx_queue, wait); 381 382 if (rtlx == NULL) 383 return 0; 384 385 /* data available to read? */ 386 if (rtlx_read_poll(minor, 0)) 387 mask |= POLLIN | POLLRDNORM; 388 389 /* space to write */ 390 if (rtlx_write_poll(minor)) 391 mask |= POLLOUT | POLLWRNORM; 392 393 return mask; 394 } 395 396 static ssize_t file_read(struct file *file, char __user * buffer, size_t count, 397 loff_t * ppos) 398 { 399 int minor = iminor(file->f_path.dentry->d_inode); 400 401 /* data available? */ 402 if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) { 403 return 0; // -EAGAIN makes cat whinge 404 } 405 406 return rtlx_read(minor, buffer, count, 1); 407 } 408 409 static ssize_t file_write(struct file *file, const char __user * buffer, 410 size_t count, loff_t * ppos) 411 { 412 int minor; 413 struct rtlx_channel *rt; 414 415 minor = iminor(file->f_path.dentry->d_inode); 416 rt = &rtlx->channel[minor]; 417 418 /* any space left... */ 419 if (!rtlx_write_poll(minor)) { 420 int ret = 0; 421 422 if (file->f_flags & O_NONBLOCK) 423 return -EAGAIN; 424 425 __wait_event_interruptible(channel_wqs[minor].rt_queue, 426 rtlx_write_poll(minor), 427 ret); 428 if (ret) 429 return ret; 430 } 431 432 return rtlx_write(minor, (void *)buffer, count, 1); 433 } 434 435 static const struct file_operations rtlx_fops = { 436 .owner = THIS_MODULE, 437 .open = file_open, 438 .release = file_release, 439 .write = file_write, 440 .read = file_read, 441 .poll = file_poll 442 }; 443 444 static struct irqaction rtlx_irq = { 445 .handler = rtlx_interrupt, 446 .flags = IRQF_DISABLED, 447 .name = "RTLX", 448 }; 449 450 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ; 451 452 static char register_chrdev_failed[] __initdata = 453 KERN_ERR "rtlx_module_init: unable to register device\n"; 454 455 static int rtlx_module_init(void) 456 { 457 struct device *dev; 458 int i, err; 459 460 major = register_chrdev(0, module_name, &rtlx_fops); 461 if (major < 0) { 462 printk(register_chrdev_failed); 463 return major; 464 } 465 466 /* initialise the wait queues */ 467 for (i = 0; i < RTLX_CHANNELS; i++) { 468 init_waitqueue_head(&channel_wqs[i].rt_queue); 469 init_waitqueue_head(&channel_wqs[i].lx_queue); 470 atomic_set(&channel_wqs[i].in_open, 0); 471 472 dev = device_create(mt_class, NULL, MKDEV(major, i), 473 "%s%d", module_name, i); 474 if (IS_ERR(dev)) { 475 err = PTR_ERR(dev); 476 goto out_chrdev; 477 } 478 } 479 480 /* set up notifiers */ 481 notify.start = starting; 482 notify.stop = stopping; 483 vpe_notify(RTLX_TARG_VPE, ¬ify); 484 485 if (cpu_has_vint) 486 set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch); 487 488 rtlx_irq.dev_id = rtlx; 489 setup_irq(rtlx_irq_num, &rtlx_irq); 490 491 return 0; 492 493 out_chrdev: 494 for (i = 0; i < RTLX_CHANNELS; i++) 495 device_destroy(mt_class, MKDEV(major, i)); 496 497 return err; 498 } 499 500 static void __exit rtlx_module_exit(void) 501 { 502 int i; 503 504 for (i = 0; i < RTLX_CHANNELS; i++) 505 device_destroy(mt_class, MKDEV(major, i)); 506 507 unregister_chrdev(major, module_name); 508 } 509 510 module_init(rtlx_module_init); 511 module_exit(rtlx_module_exit); 512 513 MODULE_DESCRIPTION("MIPS RTLX"); 514 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc."); 515 MODULE_LICENSE("GPL"); 516