summaryrefslogtreecommitdiffstats
path: root/arch/mips/kernel/rtlx.c
blob: ce72bfff5e29298c5c065bb59f0473295054443b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
/*
 * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved.
 * Copyright (C) 2005, 06 Ralf Baechle (ralf@linux-mips.org)
 *
 *  This program is free software; you can distribute it and/or modify it
 *  under the terms of the GNU General Public License (Version 2) as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <linux/list.h>
#include <linux/vmalloc.h>
#include <linux/elf.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/moduleloader.h>
#include <linux/interrupt.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <asm/mipsmtregs.h>
#include <asm/mips_mt.h>
#include <asm/cacheflush.h>
#include <linux/atomic.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/vpe.h>
#include <asm/rtlx.h>

static struct rtlx_info *rtlx;
static int major;
static char module_name[] = "rtlx";

static struct chan_waitqueues {
	wait_queue_head_t rt_queue;
	wait_queue_head_t lx_queue;
	atomic_t in_open;
	struct mutex mutex;
} channel_wqs[RTLX_CHANNELS];

static struct vpe_notifications notify;
static int sp_stopping;

extern void *vpe_get_shared(int index);

static void rtlx_dispatch(void)
{
	do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ);
}


/* Interrupt handler may be called before rtlx_init has otherwise had
   a chance to run.
*/
static irqreturn_t rtlx_interrupt(int irq, void *dev_id)
{
	unsigned int vpeflags;
	unsigned long flags;
	int i;

	/* Ought not to be strictly necessary for SMTC builds */
	local_irq_save(flags);
	vpeflags = dvpe();
	set_c0_status(0x100 << MIPS_CPU_RTLX_IRQ);
	irq_enable_hazard();
	evpe(vpeflags);
	local_irq_restore(flags);

	for (i = 0; i < RTLX_CHANNELS; i++) {
			wake_up(&channel_wqs[i].lx_queue);
			wake_up(&channel_wqs[i].rt_queue);
	}

	return IRQ_HANDLED;
}

static void __used dump_rtlx(void)
{
	int i;

	printk("id 0x%lx state %d\n", rtlx->id, rtlx->state);

	for (i = 0; i < RTLX_CHANNELS; i++) {
		struct rtlx_channel *chan = &rtlx->channel[i];

		printk(" rt_state %d lx_state %d buffer_size %d\n",
		       chan->rt_state, chan->lx_state, chan->buffer_size);

		printk(" rt_read %d rt_write %d\n",
		       chan->rt_read, chan->rt_write);

		printk(" lx_read %d lx_write %d\n",
		       chan->lx_read, chan->lx_write);

		printk(" rt_buffer <%s>\n", chan->rt_buffer);
		printk(" lx_buffer <%s>\n", chan->lx_buffer);
	}
}

/* call when we have the address of the shared structure from the SP side. */
static int rtlx_init(struct rtlx_info *rtlxi)
{
	if (rtlxi->id != RTLX_ID) {
		printk(KERN_ERR "no valid RTLX id at 0x%p 0x%lx\n",
			rtlxi, rtlxi->id);
		return -ENOEXEC;
	}

	rtlx = rtlxi;

	return 0;
}

/* notifications */
static void starting(int vpe)
{
	int i;
	sp_stopping = 0;

	/* force a reload of rtlx */
	rtlx=NULL;

	/* wake up any sleeping rtlx_open's */
	for (i = 0; i < RTLX_CHANNELS; i++)
		wake_up_interruptible(&channel_wqs[i].lx_queue);
}

static void stopping(int vpe)
{
	int i;

	sp_stopping = 1;
	for (i = 0; i < RTLX_CHANNELS; i++)
		wake_up_interruptible(&channel_wqs[i].lx_queue);
}


int rtlx_open(int index, int can_sleep)
{
	struct rtlx_info **p;
	struct rtlx_channel *chan;
	enum rtlx_state state;
	int ret = 0;

	if (index >= RTLX_CHANNELS) {
		printk(KERN_DEBUG "rtlx_open index out of range\n");
		return -ENOSYS;
	}

	if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {
		printk(KERN_DEBUG "rtlx_open channel %d already opened\n",
		       index);
		ret = -EBUSY;
		goto out_fail;
	}

	if (rtlx == NULL) {
		if( (p = vpe_get_shared(tclimit)) == NULL) {
		    if (can_sleep) {
			__wait_event_interruptible(channel_wqs[index].lx_queue,
				(p = vpe_get_shared(tclimit)), ret);
			if (ret)
				goto out_fail;
		    } else {
			printk(KERN_DEBUG "No SP program loaded, and device "
					"opened with O_NONBLOCK\n");
			ret = -ENOSYS;
			goto out_fail;
		    }
		}

		smp_rmb();
		if (*p == NULL) {
			if (can_sleep) {
				DEFINE_WAIT(wait);

				for (;;) {
					prepare_to_wait(
						&channel_wqs[index].lx_queue,
						&wait, TASK_INTERRUPTIBLE);
					smp_rmb();
					if (*p != NULL)
						break;
					if (!signal_pending(current)) {
						schedule();
						continue;
					}
					ret = -ERESTARTSYS;
					goto out_fail;
				}
				finish_wait(&channel_wqs[index].lx_queue, &wait);
			} else {
				pr_err(" *vpe_get_shared is NULL. "
				       "Has an SP program been loaded?\n");
				ret = -ENOSYS;
				goto out_fail;
			}
		}

		if ((unsigned int)*p < KSEG0) {
			printk(KERN_WARNING "vpe_get_shared returned an "
			       "invalid pointer maybe an error code %d\n",
			       (int)*p);
			ret = -ENOSYS;
			goto out_fail;
		}

		if ((ret = rtlx_init(*p)) < 0)
			goto out_ret;
	}

	chan = &rtlx->channel[index];

	state = xchg(&chan->lx_state, RTLX_STATE_OPENED);
	if (state == RTLX_STATE_OPENED) {
		ret = -EBUSY;
		goto out_fail;
	}

out_fail:
	smp_mb();
	atomic_dec(&channel_wqs[index].in_open);
	smp_mb();

out_ret:
	return ret;
}

int rtlx_release(int index)
{
	if (rtlx == NULL) {
		pr_err("rtlx_release() with null rtlx\n");
		return 0;
	}
	rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;
	return 0;
}

unsigned int rtlx_read_poll(int index, int can_sleep)
{
	struct rtlx_channel *chan;

	if (rtlx == NULL)
		return 0;

	chan = &rtlx->channel[index];

	/* data available to read? */
	if (chan->lx_read == chan->lx_write) {
		if (can_sleep) {
			int ret = 0;

			__wait_event_interruptible(channel_wqs[index].lx_queue,
				(chan->lx_read != chan->lx_write) ||
				sp_stopping, ret);
			if (ret)
				return ret;

			if (sp_stopping)
				return 0;
		} else
			return 0;
	}

	return (chan->lx_write + chan->buffer_size - chan->lx_read)
	       % chan->buffer_size;
}

static inline int write_spacefree(int read, int write, int size)
{
	if (read == write) {
		/*
		 * Never fill the buffer completely, so indexes are always
		 * equal if empty and only empty, or !equal if data available
		 */
		return size - 1;
	}

	return ((read + size - write) % size) - 1;
}

unsigned int rtlx_write_poll(int index)
{
	struct rtlx_channel *chan = &rtlx->channel[index];

	return write_spacefree(chan->rt_read, chan->rt_write,
				chan->buffer_size);
}

ssize_t rtlx_read(int index, void __user *buff, size_t count)
{
	size_t lx_write, fl = 0L;
	struct rtlx_channel *lx;
	unsigned long failed;

	if (rtlx == NULL)
		return -ENOSYS;

	lx = &rtlx->channel[index];

	mutex_lock(&channel_wqs[index].mutex);
	smp_rmb();
	lx_write = lx->lx_write;

	/* find out how much in total */
	count = min(count,
		     (size_t)(lx_write + lx->buffer_size - lx->lx_read)
		     % lx->buffer_size);

	/* then how much from the read pointer onwards */
	fl = min(count, (size_t)lx->buffer_size - lx->lx_read);

	failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
	if (failed)
		goto out;

	/* and if there is anything left at the beginning of the buffer */
	if (count - fl)
		failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);

out:
	count -= failed;

	smp_wmb();
	lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
	smp_wmb();
	mutex_unlock(&channel_wqs[index].mutex);

	return count;
}

ssize_t rtlx_write(int index, const void __user *buffer, size_t count)
{
	struct rtlx_channel *rt;
	unsigned long failed;
	size_t rt_read;
	size_t fl;

	if (rtlx == NULL)
		return(-ENOSYS);

	rt = &rtlx->channel[index];

	mutex_lock(&channel_wqs[index].mutex);
	smp_rmb();
	rt_read = rt->rt_read;

	/* total number of bytes to copy */
	count = min(count, (size_t)write_spacefree(rt_read, rt->rt_write,
							rt->buffer_size));

	/* first bit from write pointer to the end of the buffer, or count */
	fl = min(count, (size_t) rt->buffer_size - rt->rt_write);

	failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
	if (failed)
		goto out;

	/* if there's any left copy to the beginning of the buffer */
	if (count - fl) {
		failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
	}

out:
	count -= failed;

	smp_wmb();
	rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
	smp_wmb();
	mutex_unlock(&channel_wqs[index].mutex);

	return count;
}


static int file_open(struct inode *inode, struct file *filp)
{
	return rtlx_open(iminor(inode), (filp->f_flags & O_NONBLOCK) ? 0 : 1);
}

static int file_release(struct inode *inode, struct file *filp)
{
	return rtlx_release(iminor(inode));
}

static unsigned int file_poll(struct file *file, poll_table * wait)
{
	int minor;
	unsigned int mask = 0;

	minor = iminor(file->f_path.dentry->d_inode);

	poll_wait(file, &channel_wqs[minor].rt_queue, wait);
	poll_wait(file, &channel_wqs[minor].lx_queue, wait);

	if (rtlx == NULL)
		return 0;

	/* data available to read? */
	if (rtlx_read_poll(minor, 0))
		mask |= POLLIN | POLLRDNORM;

	/* space to write */
	if (rtlx_write_poll(minor))
		mask |= POLLOUT | POLLWRNORM;

	return mask;
}

static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
			 loff_t * ppos)
{
	int minor = iminor(file->f_path.dentry->d_inode);

	/* data available? */
	if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) {
		return 0;	// -EAGAIN makes cat whinge
	}

	return rtlx_read(minor, buffer, count);
}

static ssize_t file_write(struct file *file, const char __user * buffer,
			  size_t count, loff_t * ppos)
{
	int minor;
	struct rtlx_channel *rt;

	minor = iminor(file->f_path.dentry->d_inode);
	rt = &rtlx->channel[minor];

	/* any space left... */
	if (!rtlx_write_poll(minor)) {
		int ret = 0;

		if (file->f_flags & O_NONBLOCK)
			return -EAGAIN;

		__wait_event_interruptible(channel_wqs[minor].rt_queue,
					   rtlx_write_poll(minor),
					   ret);
		if (ret)
			return ret;
	}

	return rtlx_write(minor, buffer, count);
}

static const struct file_operations rtlx_fops = {
	.owner =   THIS_MODULE,
	.open =	   file_open,
	.release = file_release,
	.write =   file_write,
	.read =	   file_read,
	.poll =	   file_poll,
	.llseek =  noop_llseek,
};

static struct irqaction rtlx_irq = {
	.handler	= rtlx_interrupt,
	.name		= "RTLX",
};

static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;

static char register_chrdev_failed[] __initdata =
	KERN_ERR "rtlx_module_init: unable to register device\n";

static int __init rtlx_module_init(void)
{
	struct device *dev;
	int i, err;

	if (!cpu_has_mipsmt) {
		printk("VPE loader: not a MIPS MT capable processor\n");
		return -ENODEV;
	}

	if (tclimit == 0) {
		printk(KERN_WARNING "No TCs reserved for AP/SP, not "
		       "initializing RTLX.\nPass maxtcs=<n> argument as kernel "
		       "argument\n");

		return -ENODEV;
	}

	major = register_chrdev(0, module_name, &rtlx_fops);
	if (major < 0) {
		printk(register_chrdev_failed);
		return major;
	}

	/* initialise the wait queues */
	for (i = 0; i < RTLX_CHANNELS; i++) {
		init_waitqueue_head(&channel_wqs[i].rt_queue);
		init_waitqueue_head(&channel_wqs[i].lx_queue);
		atomic_set(&channel_wqs[i].in_open, 0);
		mutex_init(&channel_wqs[i].mutex);

		dev = device_create(mt_class, NULL, MKDEV(major, i), NULL,
				    "%s%d", module_name, i);
		if (IS_ERR(dev)) {
			err = PTR_ERR(dev);
			goto out_chrdev;
		}
	}

	/* set up notifiers */
	notify.start = starting;
	notify.stop = stopping;
	vpe_notify(tclimit, &notify);

	if (cpu_has_vint)
		set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
	else {
		pr_err("APRP RTLX init on non-vectored-interrupt processor\n");
		err = -ENODEV;
		goto out_chrdev;
	}

	rtlx_irq.dev_id = rtlx;
	setup_irq(rtlx_irq_num, &rtlx_irq);

	return 0;

out_chrdev:
	for (i = 0; i < RTLX_CHANNELS; i++)
		device_destroy(mt_class, MKDEV(major, i));

	return err;
}

static void __exit rtlx_module_exit(void)
{
	int i;

	for (i = 0; i < RTLX_CHANNELS; i++)
		device_destroy(mt_class, MKDEV(major, i));

	unregister_chrdev(major, module_name);
}

module_init(rtlx_module_init);
module_exit(rtlx_module_exit);

MODULE_DESCRIPTION("MIPS RTLX");
MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
MODULE_LICENSE("GPL");