Merge git://git.infradead.org/mtd-2.6
[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/kernel.h>
21 #include <linux/module.h>
22 #include <linux/fs.h>
23 #include <linux/init.h>
24 #include <asm/uaccess.h>
25 #include <linux/slab.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/cacheflush.h>
38 #include <asm/atomic.h>
39 #include <asm/cpu.h>
40 #include <asm/processor.h>
41 #include <asm/system.h>
42 #include <asm/vpe.h>
43 #include <asm/rtlx.h>
44
45 #define RTLX_TARG_VPE 1
46
47 static struct rtlx_info *rtlx;
48 static int major;
49 static char module_name[] = "rtlx";
50
51 static struct chan_waitqueues {
52         wait_queue_head_t rt_queue;
53         wait_queue_head_t lx_queue;
54         int in_open;
55 } channel_wqs[RTLX_CHANNELS];
56
57 static struct irqaction irq;
58 static int irq_num;
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(struct pt_regs *regs)
65 {
66         do_IRQ(MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ, regs);
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, struct pt_regs *regs)
74 {
75         int i;
76
77         for (i = 0; i < RTLX_CHANNELS; i++) {
78                         wake_up(&channel_wqs[i].lx_queue);
79                         wake_up(&channel_wqs[i].rt_queue);
80         }
81
82         return IRQ_HANDLED;
83 }
84
85 static __attribute_used__ void dump_rtlx(void)
86 {
87         int i;
88
89         printk("id 0x%lx state %d\n", rtlx->id, rtlx->state);
90
91         for (i = 0; i < RTLX_CHANNELS; i++) {
92                 struct rtlx_channel *chan = &rtlx->channel[i];
93
94                 printk(" rt_state %d lx_state %d buffer_size %d\n",
95                        chan->rt_state, chan->lx_state, chan->buffer_size);
96
97                 printk(" rt_read %d rt_write %d\n",
98                        chan->rt_read, chan->rt_write);
99
100                 printk(" lx_read %d lx_write %d\n",
101                        chan->lx_read, chan->lx_write);
102
103                 printk(" rt_buffer <%s>\n", chan->rt_buffer);
104                 printk(" lx_buffer <%s>\n", chan->lx_buffer);
105         }
106 }
107
108 /* call when we have the address of the shared structure from the SP side. */
109 static int rtlx_init(struct rtlx_info *rtlxi)
110 {
111         if (rtlxi->id != RTLX_ID) {
112                 printk(KERN_ERR "no valid RTLX id at 0x%p 0x%x\n", rtlxi, rtlxi->id);
113                 return -ENOEXEC;
114         }
115
116         rtlx = rtlxi;
117
118         return 0;
119 }
120
121 /* notifications */
122 static void starting(int vpe)
123 {
124         int i;
125         sp_stopping = 0;
126
127         /* force a reload of rtlx */
128         rtlx=NULL;
129
130         /* wake up any sleeping rtlx_open's */
131         for (i = 0; i < RTLX_CHANNELS; i++)
132                 wake_up_interruptible(&channel_wqs[i].lx_queue);
133 }
134
135 static void stopping(int vpe)
136 {
137         int i;
138
139         sp_stopping = 1;
140         for (i = 0; i < RTLX_CHANNELS; i++)
141                 wake_up_interruptible(&channel_wqs[i].lx_queue);
142 }
143
144
145 int rtlx_open(int index, int can_sleep)
146 {
147         int ret;
148         struct rtlx_channel *chan;
149         volatile struct rtlx_info **p;
150
151         if (index >= RTLX_CHANNELS) {
152                 printk(KERN_DEBUG "rtlx_open index out of range\n");
153                 return -ENOSYS;
154         }
155
156         if (channel_wqs[index].in_open) {
157                 printk(KERN_DEBUG "rtlx_open channel %d already opened\n", index);
158                 return -EBUSY;
159         }
160
161         channel_wqs[index].in_open++;
162
163         if (rtlx == NULL) {
164                 if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
165                         if (can_sleep) {
166                                 DECLARE_WAITQUEUE(wait, current);
167
168                                 /* go to sleep */
169                                 add_wait_queue(&channel_wqs[index].lx_queue, &wait);
170
171                                 set_current_state(TASK_INTERRUPTIBLE);
172                                 while ((p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
173                                         schedule();
174                                         set_current_state(TASK_INTERRUPTIBLE);
175                                 }
176
177                                 set_current_state(TASK_RUNNING);
178                                 remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
179
180                                 /* back running */
181                         } else {
182                                 printk( KERN_DEBUG "No SP program loaded, and device "
183                                         "opened with O_NONBLOCK\n");
184                                 channel_wqs[index].in_open = 0;
185                                 return -ENOSYS;
186                         }
187                 }
188
189                 if (*p == NULL) {
190                         if (can_sleep) {
191                                 DECLARE_WAITQUEUE(wait, current);
192
193                                 /* go to sleep */
194                                 add_wait_queue(&channel_wqs[index].lx_queue, &wait);
195
196                                 set_current_state(TASK_INTERRUPTIBLE);
197                                 while (*p == NULL) {
198                                         schedule();
199
200                                         /* reset task state to interruptable otherwise
201                                            we'll whizz round here like a very fast loopy
202                                            thing. schedule() appears to return with state
203                                            set to TASK_RUNNING.
204
205                                            If the loaded SP program, for whatever reason,
206                                            doesn't set up the shared structure *p will never
207                                            become true. So whoever connected to either /dev/rt?
208                                            or if it was kspd, will then take up rather a lot of
209                                            processor cycles.
210                                         */
211
212                                         set_current_state(TASK_INTERRUPTIBLE);
213                                 }
214
215                                 set_current_state(TASK_RUNNING);
216                                 remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
217
218                                 /* back running */
219                         }
220                         else {
221                                 printk(" *vpe_get_shared is NULL. "
222                                        "Has an SP program been loaded?\n");
223                                 channel_wqs[index].in_open = 0;
224                                 return -ENOSYS;
225                         }
226                 }
227
228                 if ((unsigned int)*p < KSEG0) {
229                         printk(KERN_WARNING "vpe_get_shared returned an invalid pointer "
230                                "maybe an error code %d\n", (int)*p);
231                         channel_wqs[index].in_open = 0;
232                         return -ENOSYS;
233                 }
234
235                 if ((ret = rtlx_init(*p)) < 0) {
236                         channel_wqs[index].in_open = 0;
237                         return ret;
238                 }
239         }
240
241         chan = &rtlx->channel[index];
242
243         if (chan->lx_state == RTLX_STATE_OPENED) {
244                 channel_wqs[index].in_open = 0;
245                 return -EBUSY;
246         }
247
248         chan->lx_state = RTLX_STATE_OPENED;
249         channel_wqs[index].in_open = 0;
250         return 0;
251 }
252
253 int rtlx_release(int index)
254 {
255         rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;
256         return 0;
257 }
258
259 unsigned int rtlx_read_poll(int index, int can_sleep)
260 {
261         struct rtlx_channel *chan;
262
263         if (rtlx == NULL)
264                 return 0;
265
266         chan = &rtlx->channel[index];
267
268         /* data available to read? */
269         if (chan->lx_read == chan->lx_write) {
270                 if (can_sleep) {
271                         DECLARE_WAITQUEUE(wait, current);
272
273                         /* go to sleep */
274                         add_wait_queue(&channel_wqs[index].lx_queue, &wait);
275
276                         set_current_state(TASK_INTERRUPTIBLE);
277                         while (chan->lx_read == chan->lx_write) {
278                                 schedule();
279
280                                 set_current_state(TASK_INTERRUPTIBLE);
281
282                                 if (sp_stopping) {
283                                         set_current_state(TASK_RUNNING);
284                                         remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
285                                         return 0;
286                                 }
287                         }
288
289                         set_current_state(TASK_RUNNING);
290                         remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
291
292                         /* back running */
293                 }
294                 else
295                         return 0;
296         }
297
298         return (chan->lx_write + chan->buffer_size - chan->lx_read)
299                % chan->buffer_size;
300 }
301
302 static inline int write_spacefree(int read, int write, int size)
303 {
304         if (read == write) {
305                 /*
306                  * Never fill the buffer completely, so indexes are always
307                  * equal if empty and only empty, or !equal if data available
308                  */
309                 return size - 1;
310         }
311
312         return ((read + size - write) % size) - 1;
313 }
314
315 unsigned int rtlx_write_poll(int index)
316 {
317         struct rtlx_channel *chan = &rtlx->channel[index];
318         return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size);
319 }
320
321 static inline void copy_to(void *dst, void *src, size_t count, int user)
322 {
323         if (user)
324                 copy_to_user(dst, src, count);
325         else
326                 memcpy(dst, src, count);
327 }
328
329 static inline void copy_from(void *dst, void *src, size_t count, int user)
330 {
331         if (user)
332                 copy_from_user(dst, src, count);
333         else
334                 memcpy(dst, src, count);
335 }
336
337 ssize_t rtlx_read(int index, void *buff, size_t count, int user)
338 {
339         size_t fl = 0L;
340         struct rtlx_channel *lx;
341
342         if (rtlx == NULL)
343                 return -ENOSYS;
344
345         lx = &rtlx->channel[index];
346
347         /* find out how much in total */
348         count = min(count,
349                      (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read)
350                      % lx->buffer_size);
351
352         /* then how much from the read pointer onwards */
353         fl = min( count, (size_t)lx->buffer_size - lx->lx_read);
354
355         copy_to(buff, &lx->lx_buffer[lx->lx_read], fl, user);
356
357         /* and if there is anything left at the beginning of the buffer */
358         if ( count - fl )
359                 copy_to (buff + fl, lx->lx_buffer, count - fl, user);
360
361         /* update the index */
362         lx->lx_read += count;
363         lx->lx_read %= lx->buffer_size;
364
365         return count;
366 }
367
368 ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
369 {
370         struct rtlx_channel *rt;
371         size_t fl;
372
373         if (rtlx == NULL)
374                 return(-ENOSYS);
375
376         rt = &rtlx->channel[index];
377
378         /* total number of bytes to copy */
379         count = min(count,
380                     (size_t)write_spacefree(rt->rt_read, rt->rt_write,
381                                             rt->buffer_size));
382
383         /* first bit from write pointer to the end of the buffer, or count */
384         fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
385
386         copy_from (&rt->rt_buffer[rt->rt_write], buffer, fl, user);
387
388         /* if there's any left copy to the beginning of the buffer */
389         if( count - fl )
390                 copy_from (rt->rt_buffer, buffer + fl, count - fl, user);
391
392         rt->rt_write += count;
393         rt->rt_write %= rt->buffer_size;
394
395         return(count);
396 }
397
398
399 static int file_open(struct inode *inode, struct file *filp)
400 {
401         int minor = iminor(inode);
402
403         return rtlx_open(minor, (filp->f_flags & O_NONBLOCK) ? 0 : 1);
404 }
405
406 static int file_release(struct inode *inode, struct file *filp)
407 {
408         int minor = iminor(inode);
409
410         return rtlx_release(minor);
411 }
412
413 static unsigned int file_poll(struct file *file, poll_table * wait)
414 {
415         int minor;
416         unsigned int mask = 0;
417
418         minor = iminor(file->f_dentry->d_inode);
419
420         poll_wait(file, &channel_wqs[minor].rt_queue, wait);
421         poll_wait(file, &channel_wqs[minor].lx_queue, wait);
422
423         if (rtlx == NULL)
424                 return 0;
425
426         /* data available to read? */
427         if (rtlx_read_poll(minor, 0))
428                 mask |= POLLIN | POLLRDNORM;
429
430         /* space to write */
431         if (rtlx_write_poll(minor))
432                 mask |= POLLOUT | POLLWRNORM;
433
434         return mask;
435 }
436
437 static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
438                          loff_t * ppos)
439 {
440         int minor = iminor(file->f_dentry->d_inode);
441
442         /* data available? */
443         if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) {
444                 return 0;       // -EAGAIN makes cat whinge
445         }
446
447         return rtlx_read(minor, buffer, count, 1);
448 }
449
450 static ssize_t file_write(struct file *file, const char __user * buffer,
451                           size_t count, loff_t * ppos)
452 {
453         int minor;
454         struct rtlx_channel *rt;
455         DECLARE_WAITQUEUE(wait, current);
456
457         minor = iminor(file->f_dentry->d_inode);
458         rt = &rtlx->channel[minor];
459
460         /* any space left... */
461         if (!rtlx_write_poll(minor)) {
462
463                 if (file->f_flags & O_NONBLOCK)
464                         return -EAGAIN;
465
466                 add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
467                 set_current_state(TASK_INTERRUPTIBLE);
468
469                 while (!rtlx_write_poll(minor))
470                         schedule();
471
472                 set_current_state(TASK_RUNNING);
473                 remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
474         }
475
476         return rtlx_write(minor, (void *)buffer, count, 1);
477 }
478
479 static struct file_operations rtlx_fops = {
480         .owner =   THIS_MODULE,
481         .open =    file_open,
482         .release = file_release,
483         .write =   file_write,
484         .read =    file_read,
485         .poll =    file_poll
486 };
487
488 static struct irqaction rtlx_irq = {
489         .handler        = rtlx_interrupt,
490         .flags          = SA_INTERRUPT,
491         .name           = "RTLX",
492 };
493
494 static int rtlx_irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ;
495
496 static char register_chrdev_failed[] __initdata =
497         KERN_ERR "rtlx_module_init: unable to register device\n";
498
499 static int rtlx_module_init(void)
500 {
501         int i;
502
503         major = register_chrdev(0, module_name, &rtlx_fops);
504         if (major < 0) {
505                 printk(register_chrdev_failed);
506                 return major;
507         }
508
509         /* initialise the wait queues */
510         for (i = 0; i < RTLX_CHANNELS; i++) {
511                 init_waitqueue_head(&channel_wqs[i].rt_queue);
512                 init_waitqueue_head(&channel_wqs[i].lx_queue);
513                 channel_wqs[i].in_open = 0;
514         }
515
516         /* set up notifiers */
517         notify.start = starting;
518         notify.stop = stopping;
519         vpe_notify(RTLX_TARG_VPE, &notify);
520
521         if (cpu_has_vint)
522                 set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
523
524         rtlx_irq.dev_id = rtlx;
525         setup_irq(rtlx_irq_num, &rtlx_irq);
526
527         return 0;
528 }
529
530 static void __exit rtlx_module_exit(void)
531 {
532         unregister_chrdev(major, module_name);
533 }
534
535 module_init(rtlx_module_init);
536 module_exit(rtlx_module_exit);
537
538 MODULE_DESCRIPTION("MIPS RTLX");
539 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
540 MODULE_LICENSE("GPL");