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