Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus
[linux-2.6] / 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/mips_mt.h>
44 #include <asm/system.h>
45 #include <asm/vpe.h>
46 #include <asm/rtlx.h>
47
48 static struct rtlx_info *rtlx;
49 static int major;
50 static char module_name[] = "rtlx";
51
52 static struct chan_waitqueues {
53         wait_queue_head_t rt_queue;
54         wait_queue_head_t lx_queue;
55         atomic_t in_open;
56         struct mutex mutex;
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 void __used 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         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(tclimit)) == NULL) {
168                         if (can_sleep) {
169                                 __wait_event_interruptible(channel_wqs[index].lx_queue,
170                                                            (p = vpe_get_shared(tclimit)),
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                 smp_rmb();
183                 if (*p == NULL) {
184                         if (can_sleep) {
185                                 DEFINE_WAIT(wait);
186
187                                 for (;;) {
188                                         prepare_to_wait(&channel_wqs[index].lx_queue, &wait, TASK_INTERRUPTIBLE);
189                                         smp_rmb();
190                                         if (*p != NULL)
191                                                 break;
192                                         if (!signal_pending(current)) {
193                                                 schedule();
194                                                 continue;
195                                         }
196                                         ret = -ERESTARTSYS;
197                                         goto out_fail;
198                                 }
199                                 finish_wait(&channel_wqs[index].lx_queue, &wait);
200                         } else {
201                                 printk(" *vpe_get_shared is NULL. "
202                                        "Has an SP program been loaded?\n");
203                                 ret = -ENOSYS;
204                                 goto out_fail;
205                         }
206                 }
207
208                 if ((unsigned int)*p < KSEG0) {
209                         printk(KERN_WARNING "vpe_get_shared returned an invalid pointer "
210                                "maybe an error code %d\n", (int)*p);
211                         ret = -ENOSYS;
212                         goto out_fail;
213                 }
214
215                 if ((ret = rtlx_init(*p)) < 0)
216                         goto out_ret;
217         }
218
219         chan = &rtlx->channel[index];
220
221         state = xchg(&chan->lx_state, RTLX_STATE_OPENED);
222         if (state == RTLX_STATE_OPENED) {
223                 ret = -EBUSY;
224                 goto out_fail;
225         }
226
227 out_fail:
228         smp_mb();
229         atomic_dec(&channel_wqs[index].in_open);
230         smp_mb();
231
232 out_ret:
233         return ret;
234 }
235
236 int rtlx_release(int index)
237 {
238         rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;
239         return 0;
240 }
241
242 unsigned int rtlx_read_poll(int index, int can_sleep)
243 {
244         struct rtlx_channel *chan;
245
246         if (rtlx == NULL)
247                 return 0;
248
249         chan = &rtlx->channel[index];
250
251         /* data available to read? */
252         if (chan->lx_read == chan->lx_write) {
253                 if (can_sleep) {
254                         int ret = 0;
255
256                         __wait_event_interruptible(channel_wqs[index].lx_queue,
257                                                    chan->lx_read != chan->lx_write || sp_stopping,
258                                                    ret);
259                         if (ret)
260                                 return ret;
261
262                         if (sp_stopping)
263                                 return 0;
264                 } else
265                         return 0;
266         }
267
268         return (chan->lx_write + chan->buffer_size - chan->lx_read)
269                % chan->buffer_size;
270 }
271
272 static inline int write_spacefree(int read, int write, int size)
273 {
274         if (read == write) {
275                 /*
276                  * Never fill the buffer completely, so indexes are always
277                  * equal if empty and only empty, or !equal if data available
278                  */
279                 return size - 1;
280         }
281
282         return ((read + size - write) % size) - 1;
283 }
284
285 unsigned int rtlx_write_poll(int index)
286 {
287         struct rtlx_channel *chan = &rtlx->channel[index];
288         return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size);
289 }
290
291 ssize_t rtlx_read(int index, void __user *buff, size_t count)
292 {
293         size_t lx_write, fl = 0L;
294         struct rtlx_channel *lx;
295         unsigned long failed;
296
297         if (rtlx == NULL)
298                 return -ENOSYS;
299
300         lx = &rtlx->channel[index];
301
302         mutex_lock(&channel_wqs[index].mutex);
303         smp_rmb();
304         lx_write = lx->lx_write;
305
306         /* find out how much in total */
307         count = min(count,
308                      (size_t)(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         failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
315         if (failed)
316                 goto out;
317
318         /* and if there is anything left at the beginning of the buffer */
319         if (count - fl)
320                 failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);
321
322 out:
323         count -= failed;
324
325         smp_wmb();
326         lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
327         smp_wmb();
328         mutex_unlock(&channel_wqs[index].mutex);
329
330         return count;
331 }
332
333 ssize_t rtlx_write(int index, const void __user *buffer, size_t count)
334 {
335         struct rtlx_channel *rt;
336         unsigned long failed;
337         size_t rt_read;
338         size_t fl;
339
340         if (rtlx == NULL)
341                 return(-ENOSYS);
342
343         rt = &rtlx->channel[index];
344
345         mutex_lock(&channel_wqs[index].mutex);
346         smp_rmb();
347         rt_read = rt->rt_read;
348
349         /* total number of bytes to copy */
350         count = min(count,
351                     (size_t)write_spacefree(rt_read, rt->rt_write, rt->buffer_size));
352
353         /* first bit from write pointer to the end of the buffer, or count */
354         fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
355
356         failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
357         if (failed)
358                 goto out;
359
360         /* if there's any left copy to the beginning of the buffer */
361         if (count - fl) {
362                 failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
363         }
364
365 out:
366         count -= failed;
367
368         smp_wmb();
369         rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
370         smp_wmb();
371         mutex_unlock(&channel_wqs[index].mutex);
372
373         return count;
374 }
375
376
377 static int file_open(struct inode *inode, struct file *filp)
378 {
379         int minor = iminor(inode);
380
381         return rtlx_open(minor, (filp->f_flags & O_NONBLOCK) ? 0 : 1);
382 }
383
384 static int file_release(struct inode *inode, struct file *filp)
385 {
386         int minor = iminor(inode);
387
388         return rtlx_release(minor);
389 }
390
391 static unsigned int file_poll(struct file *file, poll_table * wait)
392 {
393         int minor;
394         unsigned int mask = 0;
395
396         minor = iminor(file->f_path.dentry->d_inode);
397
398         poll_wait(file, &channel_wqs[minor].rt_queue, wait);
399         poll_wait(file, &channel_wqs[minor].lx_queue, wait);
400
401         if (rtlx == NULL)
402                 return 0;
403
404         /* data available to read? */
405         if (rtlx_read_poll(minor, 0))
406                 mask |= POLLIN | POLLRDNORM;
407
408         /* space to write */
409         if (rtlx_write_poll(minor))
410                 mask |= POLLOUT | POLLWRNORM;
411
412         return mask;
413 }
414
415 static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
416                          loff_t * ppos)
417 {
418         int minor = iminor(file->f_path.dentry->d_inode);
419
420         /* data available? */
421         if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) {
422                 return 0;       // -EAGAIN makes cat whinge
423         }
424
425         return rtlx_read(minor, buffer, count);
426 }
427
428 static ssize_t file_write(struct file *file, const char __user * buffer,
429                           size_t count, loff_t * ppos)
430 {
431         int minor;
432         struct rtlx_channel *rt;
433
434         minor = iminor(file->f_path.dentry->d_inode);
435         rt = &rtlx->channel[minor];
436
437         /* any space left... */
438         if (!rtlx_write_poll(minor)) {
439                 int ret = 0;
440
441                 if (file->f_flags & O_NONBLOCK)
442                         return -EAGAIN;
443
444                 __wait_event_interruptible(channel_wqs[minor].rt_queue,
445                                            rtlx_write_poll(minor),
446                                            ret);
447                 if (ret)
448                         return ret;
449         }
450
451         return rtlx_write(minor, buffer, count);
452 }
453
454 static const struct file_operations rtlx_fops = {
455         .owner =   THIS_MODULE,
456         .open =    file_open,
457         .release = file_release,
458         .write =   file_write,
459         .read =    file_read,
460         .poll =    file_poll
461 };
462
463 static struct irqaction rtlx_irq = {
464         .handler        = rtlx_interrupt,
465         .flags          = IRQF_DISABLED,
466         .name           = "RTLX",
467 };
468
469 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
470
471 static char register_chrdev_failed[] __initdata =
472         KERN_ERR "rtlx_module_init: unable to register device\n";
473
474 static int __init rtlx_module_init(void)
475 {
476         struct device *dev;
477         int i, err;
478
479         if (!cpu_has_mipsmt) {
480                 printk("VPE loader: not a MIPS MT capable processor\n");
481                 return -ENODEV;
482         }
483
484         if (tclimit == 0) {
485                 printk(KERN_WARNING "No TCs reserved for AP/SP, not "
486                        "initializing RTLX.\nPass maxtcs=<n> argument as kernel "
487                        "argument\n");
488
489                 return -ENODEV;
490         }
491
492         major = register_chrdev(0, module_name, &rtlx_fops);
493         if (major < 0) {
494                 printk(register_chrdev_failed);
495                 return major;
496         }
497
498         /* initialise the wait queues */
499         for (i = 0; i < RTLX_CHANNELS; i++) {
500                 init_waitqueue_head(&channel_wqs[i].rt_queue);
501                 init_waitqueue_head(&channel_wqs[i].lx_queue);
502                 atomic_set(&channel_wqs[i].in_open, 0);
503                 mutex_init(&channel_wqs[i].mutex);
504
505                 dev = device_create(mt_class, NULL, MKDEV(major, i),
506                                     "%s%d", module_name, i);
507                 if (IS_ERR(dev)) {
508                         err = PTR_ERR(dev);
509                         goto out_chrdev;
510                 }
511         }
512
513         /* set up notifiers */
514         notify.start = starting;
515         notify.stop = stopping;
516         vpe_notify(tclimit, &notify);
517
518         if (cpu_has_vint)
519                 set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
520
521         rtlx_irq.dev_id = rtlx;
522         setup_irq(rtlx_irq_num, &rtlx_irq);
523
524         return 0;
525
526 out_chrdev:
527         for (i = 0; i < RTLX_CHANNELS; i++)
528                 device_destroy(mt_class, MKDEV(major, i));
529
530         return err;
531 }
532
533 static void __exit rtlx_module_exit(void)
534 {
535         int i;
536
537         for (i = 0; i < RTLX_CHANNELS; i++)
538                 device_destroy(mt_class, MKDEV(major, i));
539
540         unregister_chrdev(major, module_name);
541 }
542
543 module_init(rtlx_module_init);
544 module_exit(rtlx_module_exit);
545
546 MODULE_DESCRIPTION("MIPS RTLX");
547 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
548 MODULE_LICENSE("GPL");