arch/mips/kernel/rtlx.c

   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         int 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         int ret;
 150         struct rtlx_channel *chan;
 151         volatile struct rtlx_info **p;
 152
 153         if (index >= RTLX_CHANNELS) {
 154                 printk(KERN_DEBUG "rtlx_open index out of range\n");
 155                 return -ENOSYS;
 156         }
 157
 158         if (channel_wqs[index].in_open) {
 159                 printk(KERN_DEBUG "rtlx_open channel %d already opened\n", index);
 160                 return -EBUSY;
 161         }
 162
 163         channel_wqs[index].in_open++;
 164
 165         if (rtlx == NULL) {
 166                 if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
 167                         if (can_sleep) {
 168                                 DECLARE_WAITQUEUE(wait, current);
 169
 170                                 /* go to sleep */
 171                                 add_wait_queue(&channel_wqs[index].lx_queue, &wait);
 172
 173                                 set_current_state(TASK_INTERRUPTIBLE);
 174                                 while ((p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
 175                                         schedule();
 176                                         set_current_state(TASK_INTERRUPTIBLE);
 177                                 }
 178
 179                                 set_current_state(TASK_RUNNING);
 180                                 remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
 181
 182                                 /* back running */
 183                         } else {
 184                                 printk( KERN_DEBUG "No SP program loaded, and device "
 185                                         "opened with O_NONBLOCK\n");
 186                                 channel_wqs[index].in_open = 0;
 187                                 return -ENOSYS;
 188                         }
 189                 }
 190
 191                 if (*p == NULL) {
 192                         if (can_sleep) {
 193                                 DECLARE_WAITQUEUE(wait, current);
 194
 195                                 /* go to sleep */
 196                                 add_wait_queue(&channel_wqs[index].lx_queue, &wait);
 197
 198                                 set_current_state(TASK_INTERRUPTIBLE);
 199                                 while (*p == NULL) {
 200                                         schedule();
 201
 202                                         /* reset task state to interruptable otherwise
 203                                            we'll whizz round here like a very fast loopy
 204                                            thing. schedule() appears to return with state
 205                                            set to TASK_RUNNING.
 206
 207                                            If the loaded SP program, for whatever reason,
 208                                            doesn't set up the shared structure *p will never
 209                                            become true. So whoever connected to either /dev/rt?
 210                                            or if it was kspd, will then take up rather a lot of
 211                                            processor cycles.
 212                                         */
 213
 214                                         set_current_state(TASK_INTERRUPTIBLE);
 215                                 }
 216
 217                                 set_current_state(TASK_RUNNING);
 218                                 remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
 219
 220                                 /* back running */
 221                         }
 222                         else {
 223                                 printk(" *vpe_get_shared is NULL. "
 224                                        "Has an SP program been loaded?\n");
 225                                 channel_wqs[index].in_open = 0;
 226                                 return -ENOSYS;
 227                         }
 228                 }
 229
 230                 if ((unsigned int)*p < KSEG0) {
 231                         printk(KERN_WARNING "vpe_get_shared returned an invalid pointer "
 232                                "maybe an error code %d\n", (int)*p);
 233                         channel_wqs[index].in_open = 0;
 234                         return -ENOSYS;
 235                 }
 236
 237                 if ((ret = rtlx_init(*p)) < 0) {
 238                         channel_wqs[index].in_open = 0;
 239                         return ret;
 240                 }
 241         }
 242
 243         chan = &rtlx->channel[index];
 244
 245         if (chan->lx_state == RTLX_STATE_OPENED) {
 246                 channel_wqs[index].in_open = 0;
 247                 return -EBUSY;
 248         }
 249
 250         chan->lx_state = RTLX_STATE_OPENED;
 251         channel_wqs[index].in_open = 0;
 252         return 0;
 253 }
 254
 255 int rtlx_release(int index)
 256 {
 257         rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;
 258         return 0;
 259 }
 260
 261 unsigned int rtlx_read_poll(int index, int can_sleep)
 262 {
 263         struct rtlx_channel *chan;
 264
 265         if (rtlx == NULL)
 266                 return 0;
 267
 268         chan = &rtlx->channel[index];
 269
 270         /* data available to read? */
 271         if (chan->lx_read == chan->lx_write) {
 272                 if (can_sleep) {
 273                         DECLARE_WAITQUEUE(wait, current);
 274
 275                         /* go to sleep */
 276                         add_wait_queue(&channel_wqs[index].lx_queue, &wait);
 277
 278                         set_current_state(TASK_INTERRUPTIBLE);
 279                         while (chan->lx_read == chan->lx_write) {
 280                                 schedule();
 281
 282                                 set_current_state(TASK_INTERRUPTIBLE);
 283
 284                                 if (sp_stopping) {
 285                                         set_current_state(TASK_RUNNING);
 286                                         remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
 287                                         return 0;
 288                                 }
 289                         }
 290
 291                         set_current_state(TASK_RUNNING);
 292                         remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
 293
 294                         /* back running */
 295                 }
 296                 else
 297                         return 0;
 298         }
 299
 300         return (chan->lx_write + chan->buffer_size - chan->lx_read)
 301                % chan->buffer_size;
 302 }
 303
 304 static inline int write_spacefree(int read, int write, int size)
 305 {
 306         if (read == write) {
 307                 /*
 308                  * Never fill the buffer completely, so indexes are always
 309                  * equal if empty and only empty, or !equal if data available
 310                  */
 311                 return size - 1;
 312         }
 313
 314         return ((read + size - write) % size) - 1;
 315 }
 316
 317 unsigned int rtlx_write_poll(int index)
 318 {
 319         struct rtlx_channel *chan = &rtlx->channel[index];
 320         return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size);
 321 }
 322
 323 static inline void copy_to(void *dst, void *src, size_t count, int user)
 324 {
 325         if (user)
 326                 copy_to_user(dst, src, count);
 327         else
 328                 memcpy(dst, src, count);
 329 }
 330
 331 static inline void copy_from(void *dst, void *src, size_t count, int user)
 332 {
 333         if (user)
 334                 copy_from_user(dst, src, count);
 335         else
 336                 memcpy(dst, src, count);
 337 }
 338
 339 ssize_t rtlx_read(int index, void *buff, size_t count, int user)
 340 {
 341         size_t fl = 0L;
 342         struct rtlx_channel *lx;
 343
 344         if (rtlx == NULL)
 345                 return -ENOSYS;
 346
 347         lx = &rtlx->channel[index];
 348
 349         /* find out how much in total */
 350         count = min(count,
 351                      (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read)
 352                      % lx->buffer_size);
 353
 354         /* then how much from the read pointer onwards */
 355         fl = min( count, (size_t)lx->buffer_size - lx->lx_read);
 356
 357         copy_to(buff, &lx->lx_buffer[lx->lx_read], fl, user);
 358
 359         /* and if there is anything left at the beginning of the buffer */
 360         if ( count - fl )
 361                 copy_to (buff + fl, lx->lx_buffer, count - fl, user);
 362
 363         /* update the index */
 364         lx->lx_read += count;
 365         lx->lx_read %= lx->buffer_size;
 366
 367         return count;
 368 }
 369
 370 ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
 371 {
 372         struct rtlx_channel *rt;
 373         size_t fl;
 374
 375         if (rtlx == NULL)
 376                 return(-ENOSYS);
 377
 378         rt = &rtlx->channel[index];
 379
 380         /* total number of bytes to copy */
 381         count = min(count,
 382                     (size_t)write_spacefree(rt->rt_read, rt->rt_write,
 383                                             rt->buffer_size));
 384
 385         /* first bit from write pointer to the end of the buffer, or count */
 386         fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
 387
 388         copy_from (&rt->rt_buffer[rt->rt_write], buffer, fl, user);
 389
 390         /* if there's any left copy to the beginning of the buffer */
 391         if( count - fl )
 392                 copy_from (rt->rt_buffer, buffer + fl, count - fl, user);
 393
 394         rt->rt_write += count;
 395         rt->rt_write %= rt->buffer_size;
 396
 397         return(count);
 398 }
 399
 400
 401 static int file_open(struct inode *inode, struct file *filp)
 402 {
 403         int minor = iminor(inode);
 404
 405         return rtlx_open(minor, (filp->f_flags & O_NONBLOCK) ? 0 : 1);
 406 }
 407
 408 static int file_release(struct inode *inode, struct file *filp)
 409 {
 410         int minor = iminor(inode);
 411
 412         return rtlx_release(minor);
 413 }
 414
 415 static unsigned int file_poll(struct file *file, poll_table * wait)
 416 {
 417         int minor;
 418         unsigned int mask = 0;
 419
 420         minor = iminor(file->f_path.dentry->d_inode);
 421
 422         poll_wait(file, &channel_wqs[minor].rt_queue, wait);
 423         poll_wait(file, &channel_wqs[minor].lx_queue, wait);
 424
 425         if (rtlx == NULL)
 426                 return 0;
 427
 428         /* data available to read? */
 429         if (rtlx_read_poll(minor, 0))
 430                 mask |= POLLIN | POLLRDNORM;
 431
 432         /* space to write */
 433         if (rtlx_write_poll(minor))
 434                 mask |= POLLOUT | POLLWRNORM;
 435
 436         return mask;
 437 }
 438
 439 static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
 440                          loff_t * ppos)
 441 {
 442         int minor = iminor(file->f_path.dentry->d_inode);
 443
 444         /* data available? */
 445         if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) {
 446                 return 0;       // -EAGAIN makes cat whinge
 447         }
 448
 449         return rtlx_read(minor, buffer, count, 1);
 450 }
 451
 452 static ssize_t file_write(struct file *file, const char __user * buffer,
 453                           size_t count, loff_t * ppos)
 454 {
 455         int minor;
 456         struct rtlx_channel *rt;
 457         DECLARE_WAITQUEUE(wait, current);
 458
 459         minor = iminor(file->f_path.dentry->d_inode);
 460         rt = &rtlx->channel[minor];
 461
 462         /* any space left... */
 463         if (!rtlx_write_poll(minor)) {
 464
 465                 if (file->f_flags & O_NONBLOCK)
 466                         return -EAGAIN;
 467
 468                 add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
 469                 set_current_state(TASK_INTERRUPTIBLE);
 470
 471                 while (!rtlx_write_poll(minor))
 472                         schedule();
 473
 474                 set_current_state(TASK_RUNNING);
 475                 remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
 476         }
 477
 478         return rtlx_write(minor, (void *)buffer, count, 1);
 479 }
 480
 481 static const struct file_operations rtlx_fops = {
 482         .owner =   THIS_MODULE,
 483         .open =    file_open,
 484         .release = file_release,
 485         .write =   file_write,
 486         .read =    file_read,
 487         .poll =    file_poll
 488 };
 489
 490 static struct irqaction rtlx_irq = {
 491         .handler        = rtlx_interrupt,
 492         .flags          = IRQF_DISABLED,
 493         .name           = "RTLX",
 494 };
 495
 496 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
 497
 498 static char register_chrdev_failed[] __initdata =
 499         KERN_ERR "rtlx_module_init: unable to register device\n";
 500
 501 static int rtlx_module_init(void)
 502 {
 503         struct device *dev;
 504         int i, err;
 505
 506         major = register_chrdev(0, module_name, &rtlx_fops);
 507         if (major < 0) {
 508                 printk(register_chrdev_failed);
 509                 return major;
 510         }
 511
 512         /* initialise the wait queues */
 513         for (i = 0; i < RTLX_CHANNELS; i++) {
 514                 init_waitqueue_head(&channel_wqs[i].rt_queue);
 515                 init_waitqueue_head(&channel_wqs[i].lx_queue);
 516                 channel_wqs[i].in_open = 0;
 517
 518                 dev = device_create(mt_class, NULL, MKDEV(major, i),
 519                                     "%s%d", module_name, i);
 520                 if (IS_ERR(dev)) {
 521                         err = PTR_ERR(dev);
 522                         goto out_chrdev;
 523                 }
 524         }
 525
 526         /* set up notifiers */
 527         notify.start = starting;
 528         notify.stop = stopping;
 529         vpe_notify(RTLX_TARG_VPE, &notify);
 530
 531         if (cpu_has_vint)
 532                 set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
 533
 534         rtlx_irq.dev_id = rtlx;
 535         setup_irq(rtlx_irq_num, &rtlx_irq);
 536
 537         return 0;
 538
 539 out_chrdev:
 540         for (i = 0; i < RTLX_CHANNELS; i++)
 541                 device_destroy(mt_class, MKDEV(major, i));
 542
 543         return err;
 544 }
 545
 546 static void __exit rtlx_module_exit(void)
 547 {
 548         int i;
 549
 550         for (i = 0; i < RTLX_CHANNELS; i++)
 551                 device_destroy(mt_class, MKDEV(major, i));
 552
 553         unregister_chrdev(major, module_name);
 554 }
 555
 556 module_init(rtlx_module_init);
 557 module_exit(rtlx_module_exit);
 558
 559 MODULE_DESCRIPTION("MIPS RTLX");
 560 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
 561 MODULE_LICENSE("GPL");