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