summaryrefslogtreecommitdiff
path: root/arch/mips/kernel/rtlx.c
blob: 1d855112bac254bac6328f243f22591e537a57ab (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
/*
 * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved.
 *
 *  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/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <asm/mipsmtregs.h>
#include <asm/bitops.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/rtlx.h>
#include <asm/uaccess.h>

#define RTLX_TARG_VPE 1

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

static inline int 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;
}

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

extern void *vpe_get_shared(int index);

static void rtlx_dispatch(struct pt_regs *regs)
{
	do_IRQ(MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ, regs);
}

static irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	int i;

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

		if (chan->lx_read != chan->lx_write)
			wake_up_interruptible(&channel_wqs[i].lx_queue);
	}

	return IRQ_HANDLED;
}

/* call when we have the address of the shared structure from the SP side. */
static int rtlx_init(struct rtlx_info *rtlxi)
{
	int i;

	if (rtlxi->id != RTLX_ID) {
		printk(KERN_WARNING "no valid RTLX id at 0x%p\n", rtlxi);
		return -ENOEXEC;
	}

	/* 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);
	}

	/* set up for interrupt handling */
	memset(&irq, 0, sizeof(struct irqaction));

	if (cpu_has_vint)
		set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);

	irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ;
	irq.handler = rtlx_interrupt;
	irq.flags = SA_INTERRUPT;
	irq.name = "RTLX";
	irq.dev_id = rtlx;
	setup_irq(irq_num, &irq);

	rtlx = rtlxi;

	return 0;
}

/* only allow one open process at a time to open each channel */
static int rtlx_open(struct inode *inode, struct file *filp)
{
	int minor, ret;
	struct rtlx_channel *chan;

	/* assume only 1 device at the mo. */
	minor = MINOR(inode->i_rdev);

	if (rtlx == NULL) {
		struct rtlx_info **p;
		if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
			printk(KERN_ERR "vpe_get_shared is NULL. "
			       "Has an SP program been loaded?\n");
			return -EFAULT;
		}

		if (*p == NULL) {
			printk(KERN_ERR "vpe_shared %p %p\n", p, *p);
			return -EFAULT;
		}

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

	chan = &rtlx->channel[minor];

	if (test_and_set_bit(RTLX_STATE_OPENED, &chan->lx_state))
		return -EBUSY;

	return 0;
}

static int rtlx_release(struct inode *inode, struct file *filp)
{
	int minor = MINOR(inode->i_rdev);

	clear_bit(RTLX_STATE_OPENED, &rtlx->channel[minor].lx_state);
	smp_mb__after_clear_bit();

	return 0;
}

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

	minor = MINOR(file->f_dentry->d_inode->i_rdev);
	chan = &rtlx->channel[minor];

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

	/* data available to read? */
	if (chan->lx_read != chan->lx_write)
		mask |= POLLIN | POLLRDNORM;

	/* space to write */
	if (spacefree(chan->rt_read, chan->rt_write, chan->buffer_size))
		mask |= POLLOUT | POLLWRNORM;

	return mask;
}

static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count,
			 loff_t * ppos)
{
	unsigned long failed;
	size_t fl = 0L;
	int minor;
	struct rtlx_channel *lx;
	DECLARE_WAITQUEUE(wait, current);

	minor = MINOR(file->f_dentry->d_inode->i_rdev);
	lx = &rtlx->channel[minor];

	/* data available? */
	if (lx->lx_write == lx->lx_read) {
		if (file->f_flags & O_NONBLOCK)
			return 0;	/* -EAGAIN makes cat whinge */

		/* go to sleep */
		add_wait_queue(&channel_wqs[minor].lx_queue, &wait);
		set_current_state(TASK_INTERRUPTIBLE);

		while (lx->lx_write == lx->lx_read)
			schedule();

		set_current_state(TASK_RUNNING);
		remove_wait_queue(&channel_wqs[minor].lx_queue, &wait);

		/* back running */
	}

	/* find out how much in total */
	count = min(count,
		    (size_t)(lx->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 (buffer, &lx->lx_buffer[lx->lx_read], fl);
	if (failed) {
		count = fl - failed;
		goto out;
	}

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

out:
	/* update the index */
	lx->lx_read += count;
	lx->lx_read %= lx->buffer_size;

	return count;
}

static ssize_t rtlx_write(struct file *file, const char __user * buffer,
			  size_t count, loff_t * ppos)
{
	unsigned long failed;
	int minor;
	struct rtlx_channel *rt;
	size_t fl;
	DECLARE_WAITQUEUE(wait, current);

	minor = MINOR(file->f_dentry->d_inode->i_rdev);
	rt = &rtlx->channel[minor];

	/* any space left... */
	if (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) {

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

		add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
		set_current_state(TASK_INTERRUPTIBLE);

		while (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size))
			schedule();

		set_current_state(TASK_RUNNING);
		remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
	}

	/* total number of bytes to copy */
	count = min(count, (size_t)spacefree(rt->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) {
		count = fl - 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);
		if (failed) {
			count -= failed;
			goto out;
		}
	}

out:
	rt->rt_write += count;
	rt->rt_write %= rt->buffer_size;

	return count;
}

static struct file_operations rtlx_fops = {
	.owner		= THIS_MODULE,
	.open		= rtlx_open,
	.release	= rtlx_release,
	.write		= rtlx_write,
	.read		= rtlx_read,
	.poll		= rtlx_poll
};

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

static int __init rtlx_module_init(void)
{
	major = register_chrdev(0, module_name, &rtlx_fops);
	if (major < 0) {
		printk(register_chrdev_failed);
		return major;
	}

	return 0;
}

static void __exit rtlx_module_exit(void)
{
	unregister_chrdev(major, module_name);
}

module_init(rtlx_module_init);
module_exit(rtlx_module_exit);

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