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         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, &notify);
 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");