Merge branch 'sh/for-2.6.27' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal...
[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/smp_lock.h>
32 #include <linux/syscalls.h>
33 #include <linux/moduleloader.h>
34 #include <linux/interrupt.h>
35 #include <linux/poll.h>
36 #include <linux/sched.h>
37 #include <linux/wait.h>
38 #include <asm/mipsmtregs.h>
39 #include <asm/mips_mt.h>
40 #include <asm/cacheflush.h>
41 #include <asm/atomic.h>
42 #include <asm/cpu.h>
43 #include <asm/processor.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         unsigned int flags, vpeflags;
77
78         /* Ought not to be strictly necessary for SMTC builds */
79         local_irq_save(flags);
80         vpeflags = dvpe();
81         set_c0_status(0x100 << MIPS_CPU_RTLX_IRQ);
82         irq_enable_hazard();
83         evpe(vpeflags);
84         local_irq_restore(flags);
85
86         for (i = 0; i < RTLX_CHANNELS; i++) {
87                         wake_up(&channel_wqs[i].lx_queue);
88                         wake_up(&channel_wqs[i].rt_queue);
89         }
90
91         return IRQ_HANDLED;
92 }
93
94 static void __used dump_rtlx(void)
95 {
96         int i;
97
98         printk("id 0x%lx state %d\n", rtlx->id, rtlx->state);
99
100         for (i = 0; i < RTLX_CHANNELS; i++) {
101                 struct rtlx_channel *chan = &rtlx->channel[i];
102
103                 printk(" rt_state %d lx_state %d buffer_size %d\n",
104                        chan->rt_state, chan->lx_state, chan->buffer_size);
105
106                 printk(" rt_read %d rt_write %d\n",
107                        chan->rt_read, chan->rt_write);
108
109                 printk(" lx_read %d lx_write %d\n",
110                        chan->lx_read, chan->lx_write);
111
112                 printk(" rt_buffer <%s>\n", chan->rt_buffer);
113                 printk(" lx_buffer <%s>\n", chan->lx_buffer);
114         }
115 }
116
117 /* call when we have the address of the shared structure from the SP side. */
118 static int rtlx_init(struct rtlx_info *rtlxi)
119 {
120         if (rtlxi->id != RTLX_ID) {
121                 printk(KERN_ERR "no valid RTLX id at 0x%p 0x%lx\n",
122                         rtlxi, rtlxi->id);
123                 return -ENOEXEC;
124         }
125
126         rtlx = rtlxi;
127
128         return 0;
129 }
130
131 /* notifications */
132 static void starting(int vpe)
133 {
134         int i;
135         sp_stopping = 0;
136
137         /* force a reload of rtlx */
138         rtlx=NULL;
139
140         /* wake up any sleeping rtlx_open's */
141         for (i = 0; i < RTLX_CHANNELS; i++)
142                 wake_up_interruptible(&channel_wqs[i].lx_queue);
143 }
144
145 static void stopping(int vpe)
146 {
147         int i;
148
149         sp_stopping = 1;
150         for (i = 0; i < RTLX_CHANNELS; i++)
151                 wake_up_interruptible(&channel_wqs[i].lx_queue);
152 }
153
154
155 int rtlx_open(int index, int can_sleep)
156 {
157         struct rtlx_info **p;
158         struct rtlx_channel *chan;
159         enum rtlx_state state;
160         int ret = 0;
161
162         if (index >= RTLX_CHANNELS) {
163                 printk(KERN_DEBUG "rtlx_open index out of range\n");
164                 return -ENOSYS;
165         }
166
167         if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {
168                 printk(KERN_DEBUG "rtlx_open channel %d already opened\n",
169                        index);
170                 ret = -EBUSY;
171                 goto out_fail;
172         }
173
174         if (rtlx == NULL) {
175                 if( (p = vpe_get_shared(tclimit)) == NULL) {
176                     if (can_sleep) {
177                         __wait_event_interruptible(channel_wqs[index].lx_queue,
178                                 (p = vpe_get_shared(tclimit)), ret);
179                         if (ret)
180                                 goto out_fail;
181                     } else {
182                         printk(KERN_DEBUG "No SP program loaded, and device "
183                                         "opened with O_NONBLOCK\n");
184                         ret = -ENOSYS;
185                         goto out_fail;
186                     }
187                 }
188
189                 smp_rmb();
190                 if (*p == NULL) {
191                         if (can_sleep) {
192                                 DEFINE_WAIT(wait);
193
194                                 for (;;) {
195                                         prepare_to_wait(
196                                                 &channel_wqs[index].lx_queue,
197                                                 &wait, TASK_INTERRUPTIBLE);
198                                         smp_rmb();
199                                         if (*p != NULL)
200                                                 break;
201                                         if (!signal_pending(current)) {
202                                                 schedule();
203                                                 continue;
204                                         }
205                                         ret = -ERESTARTSYS;
206                                         goto out_fail;
207                                 }
208                                 finish_wait(&channel_wqs[index].lx_queue, &wait);
209                         } else {
210                                 pr_err(" *vpe_get_shared is NULL. "
211                                        "Has an SP program been loaded?\n");
212                                 ret = -ENOSYS;
213                                 goto out_fail;
214                         }
215                 }
216
217                 if ((unsigned int)*p < KSEG0) {
218                         printk(KERN_WARNING "vpe_get_shared returned an "
219                                "invalid pointer maybe an error code %d\n",
220                                (int)*p);
221                         ret = -ENOSYS;
222                         goto out_fail;
223                 }
224
225                 if ((ret = rtlx_init(*p)) < 0)
226                         goto out_ret;
227         }
228
229         chan = &rtlx->channel[index];
230
231         state = xchg(&chan->lx_state, RTLX_STATE_OPENED);
232         if (state == RTLX_STATE_OPENED) {
233                 ret = -EBUSY;
234                 goto out_fail;
235         }
236
237 out_fail:
238         smp_mb();
239         atomic_dec(&channel_wqs[index].in_open);
240         smp_mb();
241
242 out_ret:
243         return ret;
244 }
245
246 int rtlx_release(int index)
247 {
248         if (rtlx == NULL) {
249                 pr_err("rtlx_release() with null rtlx\n");
250                 return 0;
251         }
252         rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;
253         return 0;
254 }
255
256 unsigned int rtlx_read_poll(int index, int can_sleep)
257 {
258         struct rtlx_channel *chan;
259
260         if (rtlx == NULL)
261                 return 0;
262
263         chan = &rtlx->channel[index];
264
265         /* data available to read? */
266         if (chan->lx_read == chan->lx_write) {
267                 if (can_sleep) {
268                         int ret = 0;
269
270                         __wait_event_interruptible(channel_wqs[index].lx_queue,
271                                 (chan->lx_read != chan->lx_write) ||
272                                 sp_stopping, ret);
273                         if (ret)
274                                 return ret;
275
276                         if (sp_stopping)
277                                 return 0;
278                 } else
279                         return 0;
280         }
281
282         return (chan->lx_write + chan->buffer_size - chan->lx_read)
283                % chan->buffer_size;
284 }
285
286 static inline int write_spacefree(int read, int write, int size)
287 {
288         if (read == write) {
289                 /*
290                  * Never fill the buffer completely, so indexes are always
291                  * equal if empty and only empty, or !equal if data available
292                  */
293                 return size - 1;
294         }
295
296         return ((read + size - write) % size) - 1;
297 }
298
299 unsigned int rtlx_write_poll(int index)
300 {
301         struct rtlx_channel *chan = &rtlx->channel[index];
302
303         return write_spacefree(chan->rt_read, chan->rt_write,
304                                 chan->buffer_size);
305 }
306
307 ssize_t rtlx_read(int index, void __user *buff, size_t count)
308 {
309         size_t lx_write, fl = 0L;
310         struct rtlx_channel *lx;
311         unsigned long failed;
312
313         if (rtlx == NULL)
314                 return -ENOSYS;
315
316         lx = &rtlx->channel[index];
317
318         mutex_lock(&channel_wqs[index].mutex);
319         smp_rmb();
320         lx_write = lx->lx_write;
321
322         /* find out how much in total */
323         count = min(count,
324                      (size_t)(lx_write + lx->buffer_size - lx->lx_read)
325                      % lx->buffer_size);
326
327         /* then how much from the read pointer onwards */
328         fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
329
330         failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
331         if (failed)
332                 goto out;
333
334         /* and if there is anything left at the beginning of the buffer */
335         if (count - fl)
336                 failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);
337
338 out:
339         count -= failed;
340
341         smp_wmb();
342         lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
343         smp_wmb();
344         mutex_unlock(&channel_wqs[index].mutex);
345
346         return count;
347 }
348
349 ssize_t rtlx_write(int index, const void __user *buffer, size_t count)
350 {
351         struct rtlx_channel *rt;
352         unsigned long failed;
353         size_t rt_read;
354         size_t fl;
355
356         if (rtlx == NULL)
357                 return(-ENOSYS);
358
359         rt = &rtlx->channel[index];
360
361         mutex_lock(&channel_wqs[index].mutex);
362         smp_rmb();
363         rt_read = rt->rt_read;
364
365         /* total number of bytes to copy */
366         count = min(count, (size_t)write_spacefree(rt_read, rt->rt_write,
367                                                         rt->buffer_size));
368
369         /* first bit from write pointer to the end of the buffer, or count */
370         fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
371
372         failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
373         if (failed)
374                 goto out;
375
376         /* if there's any left copy to the beginning of the buffer */
377         if (count - fl) {
378                 failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
379         }
380
381 out:
382         count -= failed;
383
384         smp_wmb();
385         rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
386         smp_wmb();
387         mutex_unlock(&channel_wqs[index].mutex);
388
389         return count;
390 }
391
392
393 static int file_open(struct inode *inode, struct file *filp)
394 {
395         int minor = iminor(inode);
396         int err;
397
398         lock_kernel();
399         err = rtlx_open(minor, (filp->f_flags & O_NONBLOCK) ? 0 : 1);
400         unlock_kernel();
401         return err;
402 }
403
404 static int file_release(struct inode *inode, struct file *filp)
405 {
406         int minor = iminor(inode);
407
408         return rtlx_release(minor);
409 }
410
411 static unsigned int file_poll(struct file *file, poll_table * wait)
412 {
413         int minor;
414         unsigned int mask = 0;
415
416         minor = iminor(file->f_path.dentry->d_inode);
417
418         poll_wait(file, &channel_wqs[minor].rt_queue, wait);
419         poll_wait(file, &channel_wqs[minor].lx_queue, wait);
420
421         if (rtlx == NULL)
422                 return 0;
423
424         /* data available to read? */
425         if (rtlx_read_poll(minor, 0))
426                 mask |= POLLIN | POLLRDNORM;
427
428         /* space to write */
429         if (rtlx_write_poll(minor))
430                 mask |= POLLOUT | POLLWRNORM;
431
432         return mask;
433 }
434
435 static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
436                          loff_t * ppos)
437 {
438         int minor = iminor(file->f_path.dentry->d_inode);
439
440         /* data available? */
441         if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) {
442                 return 0;       // -EAGAIN makes cat whinge
443         }
444
445         return rtlx_read(minor, buffer, count);
446 }
447
448 static ssize_t file_write(struct file *file, const char __user * buffer,
449                           size_t count, loff_t * ppos)
450 {
451         int minor;
452         struct rtlx_channel *rt;
453
454         minor = iminor(file->f_path.dentry->d_inode);
455         rt = &rtlx->channel[minor];
456
457         /* any space left... */
458         if (!rtlx_write_poll(minor)) {
459                 int ret = 0;
460
461                 if (file->f_flags & O_NONBLOCK)
462                         return -EAGAIN;
463
464                 __wait_event_interruptible(channel_wqs[minor].rt_queue,
465                                            rtlx_write_poll(minor),
466                                            ret);
467                 if (ret)
468                         return ret;
469         }
470
471         return rtlx_write(minor, buffer, count);
472 }
473
474 static const struct file_operations rtlx_fops = {
475         .owner =   THIS_MODULE,
476         .open =    file_open,
477         .release = file_release,
478         .write =   file_write,
479         .read =    file_read,
480         .poll =    file_poll
481 };
482
483 static struct irqaction rtlx_irq = {
484         .handler        = rtlx_interrupt,
485         .flags          = IRQF_DISABLED,
486         .name           = "RTLX",
487 };
488
489 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
490
491 static char register_chrdev_failed[] __initdata =
492         KERN_ERR "rtlx_module_init: unable to register device\n";
493
494 static int __init rtlx_module_init(void)
495 {
496         struct device *dev;
497         int i, err;
498
499         if (!cpu_has_mipsmt) {
500                 printk("VPE loader: not a MIPS MT capable processor\n");
501                 return -ENODEV;
502         }
503
504         if (tclimit == 0) {
505                 printk(KERN_WARNING "No TCs reserved for AP/SP, not "
506                        "initializing RTLX.\nPass maxtcs=<n> argument as kernel "
507                        "argument\n");
508
509                 return -ENODEV;
510         }
511
512         major = register_chrdev(0, module_name, &rtlx_fops);
513         if (major < 0) {
514                 printk(register_chrdev_failed);
515                 return major;
516         }
517
518         /* initialise the wait queues */
519         for (i = 0; i < RTLX_CHANNELS; i++) {
520                 init_waitqueue_head(&channel_wqs[i].rt_queue);
521                 init_waitqueue_head(&channel_wqs[i].lx_queue);
522                 atomic_set(&channel_wqs[i].in_open, 0);
523                 mutex_init(&channel_wqs[i].mutex);
524
525                 dev = device_create_drvdata(mt_class, NULL, MKDEV(major, i),
526                                             NULL, "%s%d", module_name, i);
527                 if (IS_ERR(dev)) {
528                         err = PTR_ERR(dev);
529                         goto out_chrdev;
530                 }
531         }
532
533         /* set up notifiers */
534         notify.start = starting;
535         notify.stop = stopping;
536         vpe_notify(tclimit, &notify);
537
538         if (cpu_has_vint)
539                 set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
540         else {
541                 pr_err("APRP RTLX init on non-vectored-interrupt processor\n");
542                 err = -ENODEV;
543                 goto out_chrdev;
544         }
545
546         rtlx_irq.dev_id = rtlx;
547         setup_irq(rtlx_irq_num, &rtlx_irq);
548
549         return 0;
550
551 out_chrdev:
552         for (i = 0; i < RTLX_CHANNELS; i++)
553                 device_destroy(mt_class, MKDEV(major, i));
554
555         return err;
556 }
557
558 static void __exit rtlx_module_exit(void)
559 {
560         int i;
561
562         for (i = 0; i < RTLX_CHANNELS; i++)
563                 device_destroy(mt_class, MKDEV(major, i));
564
565         unregister_chrdev(major, module_name);
566 }
567
568 module_init(rtlx_module_init);
569 module_exit(rtlx_module_exit);
570
571 MODULE_DESCRIPTION("MIPS RTLX");
572 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
573 MODULE_LICENSE("GPL");