Merge git://git.linux-nfs.org/pub/linux/nfs-2.6
[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 vpe_notifications notify;
60 static int sp_stopping = 0;
61
62 extern void *vpe_get_shared(int index);
63
64 static void rtlx_dispatch(void)
65 {
66         do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ);
67 }
68
69
70 /* Interrupt handler may be called before rtlx_init has otherwise had
71    a chance to run.
72 */
73 static irqreturn_t rtlx_interrupt(int irq, void *dev_id)
74 {
75         int i;
76
77         for (i = 0; i < RTLX_CHANNELS; i++) {
78                         wake_up(&channel_wqs[i].lx_queue);
79                         wake_up(&channel_wqs[i].rt_queue);
80         }
81
82         return IRQ_HANDLED;
83 }
84
85 static void __used dump_rtlx(void)
86 {
87         int i;
88
89         printk("id 0x%lx state %d\n", rtlx->id, rtlx->state);
90
91         for (i = 0; i < RTLX_CHANNELS; i++) {
92                 struct rtlx_channel *chan = &rtlx->channel[i];
93
94                 printk(" rt_state %d lx_state %d buffer_size %d\n",
95                        chan->rt_state, chan->lx_state, chan->buffer_size);
96
97                 printk(" rt_read %d rt_write %d\n",
98                        chan->rt_read, chan->rt_write);
99
100                 printk(" lx_read %d lx_write %d\n",
101                        chan->lx_read, chan->lx_write);
102
103                 printk(" rt_buffer <%s>\n", chan->rt_buffer);
104                 printk(" lx_buffer <%s>\n", chan->lx_buffer);
105         }
106 }
107
108 /* call when we have the address of the shared structure from the SP side. */
109 static int rtlx_init(struct rtlx_info *rtlxi)
110 {
111         if (rtlxi->id != RTLX_ID) {
112                 printk(KERN_ERR "no valid RTLX id at 0x%p 0x%lx\n", rtlxi, rtlxi->id);
113                 return -ENOEXEC;
114         }
115
116         rtlx = rtlxi;
117
118         return 0;
119 }
120
121 /* notifications */
122 static void starting(int vpe)
123 {
124         int i;
125         sp_stopping = 0;
126
127         /* force a reload of rtlx */
128         rtlx=NULL;
129
130         /* wake up any sleeping rtlx_open's */
131         for (i = 0; i < RTLX_CHANNELS; i++)
132                 wake_up_interruptible(&channel_wqs[i].lx_queue);
133 }
134
135 static void stopping(int vpe)
136 {
137         int i;
138
139         sp_stopping = 1;
140         for (i = 0; i < RTLX_CHANNELS; i++)
141                 wake_up_interruptible(&channel_wqs[i].lx_queue);
142 }
143
144
145 int rtlx_open(int index, int can_sleep)
146 {
147         struct rtlx_info **p;
148         struct rtlx_channel *chan;
149         enum rtlx_state state;
150         int ret = 0;
151
152         if (index >= RTLX_CHANNELS) {
153                 printk(KERN_DEBUG "rtlx_open index out of range\n");
154                 return -ENOSYS;
155         }
156
157         if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {
158                 printk(KERN_DEBUG "rtlx_open channel %d already opened\n",
159                        index);
160                 ret = -EBUSY;
161                 goto out_fail;
162         }
163
164         if (rtlx == NULL) {
165                 if( (p = vpe_get_shared(tclimit)) == NULL) {
166                         if (can_sleep) {
167                                 __wait_event_interruptible(channel_wqs[index].lx_queue,
168                                                            (p = vpe_get_shared(tclimit)),
169                                                            ret);
170                                 if (ret)
171                                         goto out_fail;
172                         } else {
173                                 printk(KERN_DEBUG "No SP program loaded, and device "
174                                         "opened with O_NONBLOCK\n");
175                                 ret = -ENOSYS;
176                                 goto out_fail;
177                         }
178                 }
179
180                 smp_rmb();
181                 if (*p == NULL) {
182                         if (can_sleep) {
183                                 DEFINE_WAIT(wait);
184
185                                 for (;;) {
186                                         prepare_to_wait(&channel_wqs[index].lx_queue, &wait, TASK_INTERRUPTIBLE);
187                                         smp_rmb();
188                                         if (*p != NULL)
189                                                 break;
190                                         if (!signal_pending(current)) {
191                                                 schedule();
192                                                 continue;
193                                         }
194                                         ret = -ERESTARTSYS;
195                                         goto out_fail;
196                                 }
197                                 finish_wait(&channel_wqs[index].lx_queue, &wait);
198                         } else {
199                                 printk(" *vpe_get_shared is NULL. "
200                                        "Has an SP program been loaded?\n");
201                                 ret = -ENOSYS;
202                                 goto out_fail;
203                         }
204                 }
205
206                 if ((unsigned int)*p < KSEG0) {
207                         printk(KERN_WARNING "vpe_get_shared returned an invalid pointer "
208                                "maybe an error code %d\n", (int)*p);
209                         ret = -ENOSYS;
210                         goto out_fail;
211                 }
212
213                 if ((ret = rtlx_init(*p)) < 0)
214                         goto out_ret;
215         }
216
217         chan = &rtlx->channel[index];
218
219         state = xchg(&chan->lx_state, RTLX_STATE_OPENED);
220         if (state == RTLX_STATE_OPENED) {
221                 ret = -EBUSY;
222                 goto out_fail;
223         }
224
225 out_fail:
226         smp_mb();
227         atomic_dec(&channel_wqs[index].in_open);
228         smp_mb();
229
230 out_ret:
231         return ret;
232 }
233
234 int rtlx_release(int index)
235 {
236         rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;
237         return 0;
238 }
239
240 unsigned int rtlx_read_poll(int index, int can_sleep)
241 {
242         struct rtlx_channel *chan;
243
244         if (rtlx == NULL)
245                 return 0;
246
247         chan = &rtlx->channel[index];
248
249         /* data available to read? */
250         if (chan->lx_read == chan->lx_write) {
251                 if (can_sleep) {
252                         int ret = 0;
253
254                         __wait_event_interruptible(channel_wqs[index].lx_queue,
255                                                    chan->lx_read != chan->lx_write || sp_stopping,
256                                                    ret);
257                         if (ret)
258                                 return ret;
259
260                         if (sp_stopping)
261                                 return 0;
262                 } else
263                         return 0;
264         }
265
266         return (chan->lx_write + chan->buffer_size - chan->lx_read)
267                % chan->buffer_size;
268 }
269
270 static inline int write_spacefree(int read, int write, int size)
271 {
272         if (read == write) {
273                 /*
274                  * Never fill the buffer completely, so indexes are always
275                  * equal if empty and only empty, or !equal if data available
276                  */
277                 return size - 1;
278         }
279
280         return ((read + size - write) % size) - 1;
281 }
282
283 unsigned int rtlx_write_poll(int index)
284 {
285         struct rtlx_channel *chan = &rtlx->channel[index];
286         return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size);
287 }
288
289 ssize_t rtlx_read(int index, void __user *buff, size_t count)
290 {
291         size_t lx_write, fl = 0L;
292         struct rtlx_channel *lx;
293         unsigned long failed;
294
295         if (rtlx == NULL)
296                 return -ENOSYS;
297
298         lx = &rtlx->channel[index];
299
300         mutex_lock(&channel_wqs[index].mutex);
301         smp_rmb();
302         lx_write = lx->lx_write;
303
304         /* find out how much in total */
305         count = min(count,
306                      (size_t)(lx_write + lx->buffer_size - lx->lx_read)
307                      % lx->buffer_size);
308
309         /* then how much from the read pointer onwards */
310         fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
311
312         failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
313         if (failed)
314                 goto out;
315
316         /* and if there is anything left at the beginning of the buffer */
317         if (count - fl)
318                 failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);
319
320 out:
321         count -= failed;
322
323         smp_wmb();
324         lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
325         smp_wmb();
326         mutex_unlock(&channel_wqs[index].mutex);
327
328         return count;
329 }
330
331 ssize_t rtlx_write(int index, const void __user *buffer, size_t count)
332 {
333         struct rtlx_channel *rt;
334         unsigned long failed;
335         size_t rt_read;
336         size_t fl;
337
338         if (rtlx == NULL)
339                 return(-ENOSYS);
340
341         rt = &rtlx->channel[index];
342
343         mutex_lock(&channel_wqs[index].mutex);
344         smp_rmb();
345         rt_read = rt->rt_read;
346
347         /* total number of bytes to copy */
348         count = min(count,
349                     (size_t)write_spacefree(rt_read, rt->rt_write, rt->buffer_size));
350
351         /* first bit from write pointer to the end of the buffer, or count */
352         fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
353
354         failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
355         if (failed)
356                 goto out;
357
358         /* if there's any left copy to the beginning of the buffer */
359         if (count - fl) {
360                 failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
361         }
362
363 out:
364         count -= failed;
365
366         smp_wmb();
367         rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
368         smp_wmb();
369         mutex_unlock(&channel_wqs[index].mutex);
370
371         return count;
372 }
373
374
375 static int file_open(struct inode *inode, struct file *filp)
376 {
377         int minor = iminor(inode);
378
379         return rtlx_open(minor, (filp->f_flags & O_NONBLOCK) ? 0 : 1);
380 }
381
382 static int file_release(struct inode *inode, struct file *filp)
383 {
384         int minor = iminor(inode);
385
386         return rtlx_release(minor);
387 }
388
389 static unsigned int file_poll(struct file *file, poll_table * wait)
390 {
391         int minor;
392         unsigned int mask = 0;
393
394         minor = iminor(file->f_path.dentry->d_inode);
395
396         poll_wait(file, &channel_wqs[minor].rt_queue, wait);
397         poll_wait(file, &channel_wqs[minor].lx_queue, wait);
398
399         if (rtlx == NULL)
400                 return 0;
401
402         /* data available to read? */
403         if (rtlx_read_poll(minor, 0))
404                 mask |= POLLIN | POLLRDNORM;
405
406         /* space to write */
407         if (rtlx_write_poll(minor))
408                 mask |= POLLOUT | POLLWRNORM;
409
410         return mask;
411 }
412
413 static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
414                          loff_t * ppos)
415 {
416         int minor = iminor(file->f_path.dentry->d_inode);
417
418         /* data available? */
419         if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) {
420                 return 0;       // -EAGAIN makes cat whinge
421         }
422
423         return rtlx_read(minor, buffer, count);
424 }
425
426 static ssize_t file_write(struct file *file, const char __user * buffer,
427                           size_t count, loff_t * ppos)
428 {
429         int minor;
430         struct rtlx_channel *rt;
431
432         minor = iminor(file->f_path.dentry->d_inode);
433         rt = &rtlx->channel[minor];
434
435         /* any space left... */
436         if (!rtlx_write_poll(minor)) {
437                 int ret = 0;
438
439                 if (file->f_flags & O_NONBLOCK)
440                         return -EAGAIN;
441
442                 __wait_event_interruptible(channel_wqs[minor].rt_queue,
443                                            rtlx_write_poll(minor),
444                                            ret);
445                 if (ret)
446                         return ret;
447         }
448
449         return rtlx_write(minor, buffer, count);
450 }
451
452 static const struct file_operations rtlx_fops = {
453         .owner =   THIS_MODULE,
454         .open =    file_open,
455         .release = file_release,
456         .write =   file_write,
457         .read =    file_read,
458         .poll =    file_poll
459 };
460
461 static struct irqaction rtlx_irq = {
462         .handler        = rtlx_interrupt,
463         .flags          = IRQF_DISABLED,
464         .name           = "RTLX",
465 };
466
467 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
468
469 static char register_chrdev_failed[] __initdata =
470         KERN_ERR "rtlx_module_init: unable to register device\n";
471
472 static int __init rtlx_module_init(void)
473 {
474         struct device *dev;
475         int i, err;
476
477         if (!cpu_has_mipsmt) {
478                 printk("VPE loader: not a MIPS MT capable processor\n");
479                 return -ENODEV;
480         }
481
482         if (tclimit == 0) {
483                 printk(KERN_WARNING "No TCs reserved for AP/SP, not "
484                        "initializing RTLX.\nPass maxtcs=<n> argument as kernel "
485                        "argument\n");
486
487                 return -ENODEV;
488         }
489
490         major = register_chrdev(0, module_name, &rtlx_fops);
491         if (major < 0) {
492                 printk(register_chrdev_failed);
493                 return major;
494         }
495
496         /* initialise the wait queues */
497         for (i = 0; i < RTLX_CHANNELS; i++) {
498                 init_waitqueue_head(&channel_wqs[i].rt_queue);
499                 init_waitqueue_head(&channel_wqs[i].lx_queue);
500                 atomic_set(&channel_wqs[i].in_open, 0);
501                 mutex_init(&channel_wqs[i].mutex);
502
503                 dev = device_create(mt_class, NULL, MKDEV(major, i),
504                                     "%s%d", module_name, i);
505                 if (IS_ERR(dev)) {
506                         err = PTR_ERR(dev);
507                         goto out_chrdev;
508                 }
509         }
510
511         /* set up notifiers */
512         notify.start = starting;
513         notify.stop = stopping;
514         vpe_notify(tclimit, &notify);
515
516         if (cpu_has_vint)
517                 set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
518
519         rtlx_irq.dev_id = rtlx;
520         setup_irq(rtlx_irq_num, &rtlx_irq);
521
522         return 0;
523
524 out_chrdev:
525         for (i = 0; i < RTLX_CHANNELS; i++)
526                 device_destroy(mt_class, MKDEV(major, i));
527
528         return err;
529 }
530
531 static void __exit rtlx_module_exit(void)
532 {
533         int i;
534
535         for (i = 0; i < RTLX_CHANNELS; i++)
536                 device_destroy(mt_class, MKDEV(major, i));
537
538         unregister_chrdev(major, module_name);
539 }
540
541 module_init(rtlx_module_init);
542 module_exit(rtlx_module_exit);
543
544 MODULE_DESCRIPTION("MIPS RTLX");
545 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
546 MODULE_LICENSE("GPL");