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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/list.h>
27#include <linux/vmalloc.h>
28#include <linux/elf.h>
29#include <linux/seq_file.h>
30#include <linux/syscalls.h>
31#include <linux/moduleloader.h>
32#include <linux/interrupt.h>
33#include <linux/poll.h>
34#include <linux/sched.h>
35#include <linux/wait.h>
36#include <asm/mipsmtregs.h>
37#include <asm/mips_mt.h>
38#include <asm/cacheflush.h>
39#include <linux/atomic.h>
40#include <asm/cpu.h>
41#include <asm/processor.h>
42#include <asm/system.h>
43#include <asm/vpe.h>
44#include <asm/rtlx.h>
45
46static struct rtlx_info *rtlx;
47static int major;
48static char module_name[] = "rtlx";
49
50static struct chan_waitqueues {
51 wait_queue_head_t rt_queue;
52 wait_queue_head_t lx_queue;
53 atomic_t in_open;
54 struct mutex mutex;
55} channel_wqs[RTLX_CHANNELS];
56
57static struct vpe_notifications notify;
58static int sp_stopping;
59
60extern void *vpe_get_shared(int index);
61
62static void rtlx_dispatch(void)
63{
64 do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ);
65}
66
67
68/* Interrupt handler may be called before rtlx_init has otherwise had
69 a chance to run.
70*/
71static irqreturn_t rtlx_interrupt(int irq, void *dev_id)
72{
73 unsigned int vpeflags;
74 unsigned long flags;
75 int i;
76
77 /* Ought not to be strictly necessary for SMTC builds */
78 local_irq_save(flags);
79 vpeflags = dvpe();
80 set_c0_status(0x100 << MIPS_CPU_RTLX_IRQ);
81 irq_enable_hazard();
82 evpe(vpeflags);
83 local_irq_restore(flags);
84
85 for (i = 0; i < RTLX_CHANNELS; i++) {
86 wake_up(&channel_wqs[i].lx_queue);
87 wake_up(&channel_wqs[i].rt_queue);
88 }
89
90 return IRQ_HANDLED;
91}
92
93static void __used dump_rtlx(void)
94{
95 int i;
96
97 printk("id 0x%lx state %d\n", rtlx->id, rtlx->state);
98
99 for (i = 0; i < RTLX_CHANNELS; i++) {
100 struct rtlx_channel *chan = &rtlx->channel[i];
101
102 printk(" rt_state %d lx_state %d buffer_size %d\n",
103 chan->rt_state, chan->lx_state, chan->buffer_size);
104
105 printk(" rt_read %d rt_write %d\n",
106 chan->rt_read, chan->rt_write);
107
108 printk(" lx_read %d lx_write %d\n",
109 chan->lx_read, chan->lx_write);
110
111 printk(" rt_buffer <%s>\n", chan->rt_buffer);
112 printk(" lx_buffer <%s>\n", chan->lx_buffer);
113 }
114}
115
116/* call when we have the address of the shared structure from the SP side. */
117static int rtlx_init(struct rtlx_info *rtlxi)
118{
119 if (rtlxi->id != RTLX_ID) {
120 printk(KERN_ERR "no valid RTLX id at 0x%p 0x%lx\n",
121 rtlxi, rtlxi->id);
122 return -ENOEXEC;
123 }
124
125 rtlx = rtlxi;
126
127 return 0;
128}
129
130/* notifications */
131static void starting(int vpe)
132{
133 int i;
134 sp_stopping = 0;
135
136 /* force a reload of rtlx */
137 rtlx=NULL;
138
139 /* wake up any sleeping rtlx_open's */
140 for (i = 0; i < RTLX_CHANNELS; i++)
141 wake_up_interruptible(&channel_wqs[i].lx_queue);
142}
143
144static void stopping(int vpe)
145{
146 int i;
147
148 sp_stopping = 1;
149 for (i = 0; i < RTLX_CHANNELS; i++)
150 wake_up_interruptible(&channel_wqs[i].lx_queue);
151}
152
153
154int rtlx_open(int index, int can_sleep)
155{
156 struct rtlx_info **p;
157 struct rtlx_channel *chan;
158 enum rtlx_state state;
159 int ret = 0;
160
161 if (index >= RTLX_CHANNELS) {
162 printk(KERN_DEBUG "rtlx_open index out of range\n");
163 return -ENOSYS;
164 }
165
166 if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {
167 printk(KERN_DEBUG "rtlx_open channel %d already opened\n",
168 index);
169 ret = -EBUSY;
170 goto out_fail;
171 }
172
173 if (rtlx == NULL) {
174 if( (p = vpe_get_shared(tclimit)) == NULL) {
175 if (can_sleep) {
176 __wait_event_interruptible(channel_wqs[index].lx_queue,
177 (p = vpe_get_shared(tclimit)), ret);
178 if (ret)
179 goto out_fail;
180 } else {
181 printk(KERN_DEBUG "No SP program loaded, and device "
182 "opened with O_NONBLOCK\n");
183 ret = -ENOSYS;
184 goto out_fail;
185 }
186 }
187
188 smp_rmb();
189 if (*p == NULL) {
190 if (can_sleep) {
191 DEFINE_WAIT(wait);
192
193 for (;;) {
194 prepare_to_wait(
195 &channel_wqs[index].lx_queue,
196 &wait, TASK_INTERRUPTIBLE);
197 smp_rmb();
198 if (*p != NULL)
199 break;
200 if (!signal_pending(current)) {
201 schedule();
202 continue;
203 }
204 ret = -ERESTARTSYS;
205 goto out_fail;
206 }
207 finish_wait(&channel_wqs[index].lx_queue, &wait);
208 } else {
209 pr_err(" *vpe_get_shared is NULL. "
210 "Has an SP program been loaded?\n");
211 ret = -ENOSYS;
212 goto out_fail;
213 }
214 }
215
216 if ((unsigned int)*p < KSEG0) {
217 printk(KERN_WARNING "vpe_get_shared returned an "
218 "invalid pointer maybe an error code %d\n",
219 (int)*p);
220 ret = -ENOSYS;
221 goto out_fail;
222 }
223
224 if ((ret = rtlx_init(*p)) < 0)
225 goto out_ret;
226 }
227
228 chan = &rtlx->channel[index];
229
230 state = xchg(&chan->lx_state, RTLX_STATE_OPENED);
231 if (state == RTLX_STATE_OPENED) {
232 ret = -EBUSY;
233 goto out_fail;
234 }
235
236out_fail:
237 smp_mb();
238 atomic_dec(&channel_wqs[index].in_open);
239 smp_mb();
240
241out_ret:
242 return ret;
243}
244
245int rtlx_release(int index)
246{
247 if (rtlx == NULL) {
248 pr_err("rtlx_release() with null rtlx\n");
249 return 0;
250 }
251 rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;
252 return 0;
253}
254
255unsigned int rtlx_read_poll(int index, int can_sleep)
256{
257 struct rtlx_channel *chan;
258
259 if (rtlx == NULL)
260 return 0;
261
262 chan = &rtlx->channel[index];
263
264 /* data available to read? */
265 if (chan->lx_read == chan->lx_write) {
266 if (can_sleep) {
267 int ret = 0;
268
269 __wait_event_interruptible(channel_wqs[index].lx_queue,
270 (chan->lx_read != chan->lx_write) ||
271 sp_stopping, ret);
272 if (ret)
273 return ret;
274
275 if (sp_stopping)
276 return 0;
277 } else
278 return 0;
279 }
280
281 return (chan->lx_write + chan->buffer_size - chan->lx_read)
282 % chan->buffer_size;
283}
284
285static inline int write_spacefree(int read, int write, int size)
286{
287 if (read == write) {
288 /*
289 * Never fill the buffer completely, so indexes are always
290 * equal if empty and only empty, or !equal if data available
291 */
292 return size - 1;
293 }
294
295 return ((read + size - write) % size) - 1;
296}
297
298unsigned int rtlx_write_poll(int index)
299{
300 struct rtlx_channel *chan = &rtlx->channel[index];
301
302 return write_spacefree(chan->rt_read, chan->rt_write,
303 chan->buffer_size);
304}
305
306ssize_t rtlx_read(int index, void __user *buff, size_t count)
307{
308 size_t lx_write, fl = 0L;
309 struct rtlx_channel *lx;
310 unsigned long failed;
311
312 if (rtlx == NULL)
313 return -ENOSYS;
314
315 lx = &rtlx->channel[index];
316
317 mutex_lock(&channel_wqs[index].mutex);
318 smp_rmb();
319 lx_write = lx->lx_write;
320
321 /* find out how much in total */
322 count = min(count,
323 (size_t)(lx_write + lx->buffer_size - lx->lx_read)
324 % lx->buffer_size);
325
326 /* then how much from the read pointer onwards */
327 fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
328
329 failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
330 if (failed)
331 goto out;
332
333 /* and if there is anything left at the beginning of the buffer */
334 if (count - fl)
335 failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);
336
337out:
338 count -= failed;
339
340 smp_wmb();
341 lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
342 smp_wmb();
343 mutex_unlock(&channel_wqs[index].mutex);
344
345 return count;
346}
347
348ssize_t rtlx_write(int index, const void __user *buffer, size_t count)
349{
350 struct rtlx_channel *rt;
351 unsigned long failed;
352 size_t rt_read;
353 size_t fl;
354
355 if (rtlx == NULL)
356 return(-ENOSYS);
357
358 rt = &rtlx->channel[index];
359
360 mutex_lock(&channel_wqs[index].mutex);
361 smp_rmb();
362 rt_read = rt->rt_read;
363
364 /* total number of bytes to copy */
365 count = min(count, (size_t)write_spacefree(rt_read, rt->rt_write,
366 rt->buffer_size));
367
368 /* first bit from write pointer to the end of the buffer, or count */
369 fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
370
371 failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
372 if (failed)
373 goto out;
374
375 /* if there's any left copy to the beginning of the buffer */
376 if (count - fl) {
377 failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
378 }
379
380out:
381 count -= failed;
382
383 smp_wmb();
384 rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
385 smp_wmb();
386 mutex_unlock(&channel_wqs[index].mutex);
387
388 return count;
389}
390
391
392static int file_open(struct inode *inode, struct file *filp)
393{
394 return rtlx_open(iminor(inode), (filp->f_flags & O_NONBLOCK) ? 0 : 1);
395}
396
397static int file_release(struct inode *inode, struct file *filp)
398{
399 return rtlx_release(iminor(inode));
400}
401
402static unsigned int file_poll(struct file *file, poll_table * wait)
403{
404 int minor;
405 unsigned int mask = 0;
406
407 minor = iminor(file->f_path.dentry->d_inode);
408
409 poll_wait(file, &channel_wqs[minor].rt_queue, wait);
410 poll_wait(file, &channel_wqs[minor].lx_queue, wait);
411
412 if (rtlx == NULL)
413 return 0;
414
415 /* data available to read? */
416 if (rtlx_read_poll(minor, 0))
417 mask |= POLLIN | POLLRDNORM;
418
419 /* space to write */
420 if (rtlx_write_poll(minor))
421 mask |= POLLOUT | POLLWRNORM;
422
423 return mask;
424}
425
426static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
427 loff_t * ppos)
428{
429 int minor = iminor(file->f_path.dentry->d_inode);
430
431 /* data available? */
432 if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) {
433 return 0; // -EAGAIN makes cat whinge
434 }
435
436 return rtlx_read(minor, buffer, count);
437}
438
439static ssize_t file_write(struct file *file, const char __user * buffer,
440 size_t count, loff_t * ppos)
441{
442 int minor;
443 struct rtlx_channel *rt;
444
445 minor = iminor(file->f_path.dentry->d_inode);
446 rt = &rtlx->channel[minor];
447
448 /* any space left... */
449 if (!rtlx_write_poll(minor)) {
450 int ret = 0;
451
452 if (file->f_flags & O_NONBLOCK)
453 return -EAGAIN;
454
455 __wait_event_interruptible(channel_wqs[minor].rt_queue,
456 rtlx_write_poll(minor),
457 ret);
458 if (ret)
459 return ret;
460 }
461
462 return rtlx_write(minor, buffer, count);
463}
464
465static const struct file_operations rtlx_fops = {
466 .owner = THIS_MODULE,
467 .open = file_open,
468 .release = file_release,
469 .write = file_write,
470 .read = file_read,
471 .poll = file_poll,
472 .llseek = noop_llseek,
473};
474
475static struct irqaction rtlx_irq = {
476 .handler = rtlx_interrupt,
477 .flags = IRQF_DISABLED,
478 .name = "RTLX",
479};
480
481static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
482
483static char register_chrdev_failed[] __initdata =
484 KERN_ERR "rtlx_module_init: unable to register device\n";
485
486static int __init rtlx_module_init(void)
487{
488 struct device *dev;
489 int i, err;
490
491 if (!cpu_has_mipsmt) {
492 printk("VPE loader: not a MIPS MT capable processor\n");
493 return -ENODEV;
494 }
495
496 if (tclimit == 0) {
497 printk(KERN_WARNING "No TCs reserved for AP/SP, not "
498 "initializing RTLX.\nPass maxtcs=<n> argument as kernel "
499 "argument\n");
500
501 return -ENODEV;
502 }
503
504 major = register_chrdev(0, module_name, &rtlx_fops);
505 if (major < 0) {
506 printk(register_chrdev_failed);
507 return major;
508 }
509
510 /* initialise the wait queues */
511 for (i = 0; i < RTLX_CHANNELS; i++) {
512 init_waitqueue_head(&channel_wqs[i].rt_queue);
513 init_waitqueue_head(&channel_wqs[i].lx_queue);
514 atomic_set(&channel_wqs[i].in_open, 0);
515 mutex_init(&channel_wqs[i].mutex);
516
517 dev = device_create(mt_class, NULL, MKDEV(major, i), NULL,
518 "%s%d", module_name, i);
519 if (IS_ERR(dev)) {
520 err = PTR_ERR(dev);
521 goto out_chrdev;
522 }
523 }
524
525 /* set up notifiers */
526 notify.start = starting;
527 notify.stop = stopping;
528 vpe_notify(tclimit, ¬ify);
529
530 if (cpu_has_vint)
531 set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
532 else {
533 pr_err("APRP RTLX init on non-vectored-interrupt processor\n");
534 err = -ENODEV;
535 goto out_chrdev;
536 }
537
538 rtlx_irq.dev_id = rtlx;
539 setup_irq(rtlx_irq_num, &rtlx_irq);
540
541 return 0;
542
543out_chrdev:
544 for (i = 0; i < RTLX_CHANNELS; i++)
545 device_destroy(mt_class, MKDEV(major, i));
546
547 return err;
548}
549
550static void __exit rtlx_module_exit(void)
551{
552 int i;
553
554 for (i = 0; i < RTLX_CHANNELS; i++)
555 device_destroy(mt_class, MKDEV(major, i));
556
557 unregister_chrdev(major, module_name);
558}
559
560module_init(rtlx_module_init);
561module_exit(rtlx_module_exit);
562
563MODULE_DESCRIPTION("MIPS RTLX");
564MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
565MODULE_LICENSE("GPL");
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved.
7 * Copyright (C) 2005, 06 Ralf Baechle (ralf@linux-mips.org)
8 * Copyright (C) 2013 Imagination Technologies Ltd.
9 */
10#include <linux/kernel.h>
11#include <linux/fs.h>
12#include <linux/syscalls.h>
13#include <linux/moduleloader.h>
14#include <linux/atomic.h>
15#include <asm/mipsmtregs.h>
16#include <asm/mips_mt.h>
17#include <asm/processor.h>
18#include <asm/rtlx.h>
19#include <asm/setup.h>
20#include <asm/vpe.h>
21
22static int sp_stopping;
23struct rtlx_info *rtlx;
24struct chan_waitqueues channel_wqs[RTLX_CHANNELS];
25struct vpe_notifications rtlx_notify;
26void (*aprp_hook)(void) = NULL;
27EXPORT_SYMBOL(aprp_hook);
28
29static void __used dump_rtlx(void)
30{
31 int i;
32
33 pr_info("id 0x%lx state %d\n", rtlx->id, rtlx->state);
34
35 for (i = 0; i < RTLX_CHANNELS; i++) {
36 struct rtlx_channel *chan = &rtlx->channel[i];
37
38 pr_info(" rt_state %d lx_state %d buffer_size %d\n",
39 chan->rt_state, chan->lx_state, chan->buffer_size);
40
41 pr_info(" rt_read %d rt_write %d\n",
42 chan->rt_read, chan->rt_write);
43
44 pr_info(" lx_read %d lx_write %d\n",
45 chan->lx_read, chan->lx_write);
46
47 pr_info(" rt_buffer <%s>\n", chan->rt_buffer);
48 pr_info(" lx_buffer <%s>\n", chan->lx_buffer);
49 }
50}
51
52/* call when we have the address of the shared structure from the SP side. */
53static int rtlx_init(struct rtlx_info *rtlxi)
54{
55 if (rtlxi->id != RTLX_ID) {
56 pr_err("no valid RTLX id at 0x%p 0x%lx\n", rtlxi, rtlxi->id);
57 return -ENOEXEC;
58 }
59
60 rtlx = rtlxi;
61
62 return 0;
63}
64
65/* notifications */
66void rtlx_starting(int vpe)
67{
68 int i;
69 sp_stopping = 0;
70
71 /* force a reload of rtlx */
72 rtlx = NULL;
73
74 /* wake up any sleeping rtlx_open's */
75 for (i = 0; i < RTLX_CHANNELS; i++)
76 wake_up_interruptible(&channel_wqs[i].lx_queue);
77}
78
79void rtlx_stopping(int vpe)
80{
81 int i;
82
83 sp_stopping = 1;
84 for (i = 0; i < RTLX_CHANNELS; i++)
85 wake_up_interruptible(&channel_wqs[i].lx_queue);
86}
87
88
89int rtlx_open(int index, int can_sleep)
90{
91 struct rtlx_info **p;
92 struct rtlx_channel *chan;
93 enum rtlx_state state;
94 int ret = 0;
95
96 if (index >= RTLX_CHANNELS) {
97 pr_debug("rtlx_open index out of range\n");
98 return -ENOSYS;
99 }
100
101 if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {
102 pr_debug("rtlx_open channel %d already opened\n", index);
103 ret = -EBUSY;
104 goto out_fail;
105 }
106
107 if (rtlx == NULL) {
108 p = vpe_get_shared(aprp_cpu_index());
109 if (p == NULL) {
110 if (can_sleep) {
111 ret = __wait_event_interruptible(
112 channel_wqs[index].lx_queue,
113 (p = vpe_get_shared(aprp_cpu_index())));
114 if (ret)
115 goto out_fail;
116 } else {
117 pr_debug("No SP program loaded, and device opened with O_NONBLOCK\n");
118 ret = -ENOSYS;
119 goto out_fail;
120 }
121 }
122
123 smp_rmb();
124 if (*p == NULL) {
125 if (can_sleep) {
126 DEFINE_WAIT(wait);
127
128 for (;;) {
129 prepare_to_wait(
130 &channel_wqs[index].lx_queue,
131 &wait, TASK_INTERRUPTIBLE);
132 smp_rmb();
133 if (*p != NULL)
134 break;
135 if (!signal_pending(current)) {
136 schedule();
137 continue;
138 }
139 ret = -ERESTARTSYS;
140 goto out_fail;
141 }
142 finish_wait(&channel_wqs[index].lx_queue,
143 &wait);
144 } else {
145 pr_err(" *vpe_get_shared is NULL. Has an SP program been loaded?\n");
146 ret = -ENOSYS;
147 goto out_fail;
148 }
149 }
150
151 if ((unsigned int)*p < KSEG0) {
152 pr_warn("vpe_get_shared returned an invalid pointer maybe an error code %d\n",
153 (int)*p);
154 ret = -ENOSYS;
155 goto out_fail;
156 }
157
158 ret = rtlx_init(*p);
159 if (ret < 0)
160 goto out_ret;
161 }
162
163 chan = &rtlx->channel[index];
164
165 state = xchg(&chan->lx_state, RTLX_STATE_OPENED);
166 if (state == RTLX_STATE_OPENED) {
167 ret = -EBUSY;
168 goto out_fail;
169 }
170
171out_fail:
172 smp_mb();
173 atomic_dec(&channel_wqs[index].in_open);
174 smp_mb();
175
176out_ret:
177 return ret;
178}
179
180int rtlx_release(int index)
181{
182 if (rtlx == NULL) {
183 pr_err("rtlx_release() with null rtlx\n");
184 return 0;
185 }
186 rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;
187 return 0;
188}
189
190unsigned int rtlx_read_poll(int index, int can_sleep)
191{
192 struct rtlx_channel *chan;
193
194 if (rtlx == NULL)
195 return 0;
196
197 chan = &rtlx->channel[index];
198
199 /* data available to read? */
200 if (chan->lx_read == chan->lx_write) {
201 if (can_sleep) {
202 int ret = __wait_event_interruptible(
203 channel_wqs[index].lx_queue,
204 (chan->lx_read != chan->lx_write) ||
205 sp_stopping);
206 if (ret)
207 return ret;
208
209 if (sp_stopping)
210 return 0;
211 } else
212 return 0;
213 }
214
215 return (chan->lx_write + chan->buffer_size - chan->lx_read)
216 % chan->buffer_size;
217}
218
219static inline int write_spacefree(int read, int write, int size)
220{
221 if (read == write) {
222 /*
223 * Never fill the buffer completely, so indexes are always
224 * equal if empty and only empty, or !equal if data available
225 */
226 return size - 1;
227 }
228
229 return ((read + size - write) % size) - 1;
230}
231
232unsigned int rtlx_write_poll(int index)
233{
234 struct rtlx_channel *chan = &rtlx->channel[index];
235
236 return write_spacefree(chan->rt_read, chan->rt_write,
237 chan->buffer_size);
238}
239
240ssize_t rtlx_read(int index, void __user *buff, size_t count)
241{
242 size_t lx_write, fl = 0L;
243 struct rtlx_channel *lx;
244 unsigned long failed;
245
246 if (rtlx == NULL)
247 return -ENOSYS;
248
249 lx = &rtlx->channel[index];
250
251 mutex_lock(&channel_wqs[index].mutex);
252 smp_rmb();
253 lx_write = lx->lx_write;
254
255 /* find out how much in total */
256 count = min(count,
257 (size_t)(lx_write + lx->buffer_size - lx->lx_read)
258 % lx->buffer_size);
259
260 /* then how much from the read pointer onwards */
261 fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
262
263 failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
264 if (failed)
265 goto out;
266
267 /* and if there is anything left at the beginning of the buffer */
268 if (count - fl)
269 failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);
270
271out:
272 count -= failed;
273
274 smp_wmb();
275 lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
276 smp_wmb();
277 mutex_unlock(&channel_wqs[index].mutex);
278
279 return count;
280}
281
282ssize_t rtlx_write(int index, const void __user *buffer, size_t count)
283{
284 struct rtlx_channel *rt;
285 unsigned long failed;
286 size_t rt_read;
287 size_t fl;
288
289 if (rtlx == NULL)
290 return -ENOSYS;
291
292 rt = &rtlx->channel[index];
293
294 mutex_lock(&channel_wqs[index].mutex);
295 smp_rmb();
296 rt_read = rt->rt_read;
297
298 /* total number of bytes to copy */
299 count = min_t(size_t, count, write_spacefree(rt_read, rt->rt_write,
300 rt->buffer_size));
301
302 /* first bit from write pointer to the end of the buffer, or count */
303 fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
304
305 failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
306 if (failed)
307 goto out;
308
309 /* if there's any left copy to the beginning of the buffer */
310 if (count - fl)
311 failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
312
313out:
314 count -= failed;
315
316 smp_wmb();
317 rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
318 smp_wmb();
319 mutex_unlock(&channel_wqs[index].mutex);
320
321 _interrupt_sp();
322
323 return count;
324}
325
326
327static int file_open(struct inode *inode, struct file *filp)
328{
329 return rtlx_open(iminor(inode), (filp->f_flags & O_NONBLOCK) ? 0 : 1);
330}
331
332static int file_release(struct inode *inode, struct file *filp)
333{
334 return rtlx_release(iminor(inode));
335}
336
337static unsigned int file_poll(struct file *file, poll_table *wait)
338{
339 int minor = iminor(file_inode(file));
340 unsigned int mask = 0;
341
342 poll_wait(file, &channel_wqs[minor].rt_queue, wait);
343 poll_wait(file, &channel_wqs[minor].lx_queue, wait);
344
345 if (rtlx == NULL)
346 return 0;
347
348 /* data available to read? */
349 if (rtlx_read_poll(minor, 0))
350 mask |= POLLIN | POLLRDNORM;
351
352 /* space to write */
353 if (rtlx_write_poll(minor))
354 mask |= POLLOUT | POLLWRNORM;
355
356 return mask;
357}
358
359static ssize_t file_read(struct file *file, char __user *buffer, size_t count,
360 loff_t *ppos)
361{
362 int minor = iminor(file_inode(file));
363
364 /* data available? */
365 if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1))
366 return 0; /* -EAGAIN makes 'cat' whine */
367
368 return rtlx_read(minor, buffer, count);
369}
370
371static ssize_t file_write(struct file *file, const char __user *buffer,
372 size_t count, loff_t *ppos)
373{
374 int minor = iminor(file_inode(file));
375
376 /* any space left... */
377 if (!rtlx_write_poll(minor)) {
378 int ret;
379
380 if (file->f_flags & O_NONBLOCK)
381 return -EAGAIN;
382
383 ret = __wait_event_interruptible(channel_wqs[minor].rt_queue,
384 rtlx_write_poll(minor));
385 if (ret)
386 return ret;
387 }
388
389 return rtlx_write(minor, buffer, count);
390}
391
392const struct file_operations rtlx_fops = {
393 .owner = THIS_MODULE,
394 .open = file_open,
395 .release = file_release,
396 .write = file_write,
397 .read = file_read,
398 .poll = file_poll,
399 .llseek = noop_llseek,
400};
401
402module_init(rtlx_module_init);
403module_exit(rtlx_module_exit);
404
405MODULE_DESCRIPTION("MIPS RTLX");
406MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
407MODULE_LICENSE("GPL");