include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit...
[linux-3.10.git] / 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/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 <asm/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
46 static struct rtlx_info *rtlx;
47 static int major;
48 static char module_name[] = "rtlx";
49
50 static 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
57 static struct vpe_notifications notify;
58 static int sp_stopping;
59
60 extern void *vpe_get_shared(int index);
61
62 static 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 */
71 static 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
93 static 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. */
117 static 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 */
131 static 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
144 static 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
154 int 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
236 out_fail:
237         smp_mb();
238         atomic_dec(&channel_wqs[index].in_open);
239         smp_mb();
240
241 out_ret:
242         return ret;
243 }
244
245 int 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
255 unsigned 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
285 static 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
298 unsigned 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
306 ssize_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
337 out:
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
348 ssize_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
380 out:
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
392 static 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
397 static int file_release(struct inode *inode, struct file *filp)
398 {
399         return rtlx_release(iminor(inode));
400 }
401
402 static 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
426 static 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
439 static 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
465 static 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 };
473
474 static struct irqaction rtlx_irq = {
475         .handler        = rtlx_interrupt,
476         .flags          = IRQF_DISABLED,
477         .name           = "RTLX",
478 };
479
480 static int rtlx_irq_num = MIPS_CPU_IRQ_BASE + MIPS_CPU_RTLX_IRQ;
481
482 static char register_chrdev_failed[] __initdata =
483         KERN_ERR "rtlx_module_init: unable to register device\n";
484
485 static int __init rtlx_module_init(void)
486 {
487         struct device *dev;
488         int i, err;
489
490         if (!cpu_has_mipsmt) {
491                 printk("VPE loader: not a MIPS MT capable processor\n");
492                 return -ENODEV;
493         }
494
495         if (tclimit == 0) {
496                 printk(KERN_WARNING "No TCs reserved for AP/SP, not "
497                        "initializing RTLX.\nPass maxtcs=<n> argument as kernel "
498                        "argument\n");
499
500                 return -ENODEV;
501         }
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                 atomic_set(&channel_wqs[i].in_open, 0);
514                 mutex_init(&channel_wqs[i].mutex);
515
516                 dev = device_create(mt_class, NULL, MKDEV(major, i), NULL,
517                                     "%s%d", module_name, i);
518                 if (IS_ERR(dev)) {
519                         err = PTR_ERR(dev);
520                         goto out_chrdev;
521                 }
522         }
523
524         /* set up notifiers */
525         notify.start = starting;
526         notify.stop = stopping;
527         vpe_notify(tclimit, &notify);
528
529         if (cpu_has_vint)
530                 set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
531         else {
532                 pr_err("APRP RTLX init on non-vectored-interrupt processor\n");
533                 err = -ENODEV;
534                 goto out_chrdev;
535         }
536
537         rtlx_irq.dev_id = rtlx;
538         setup_irq(rtlx_irq_num, &rtlx_irq);
539
540         return 0;
541
542 out_chrdev:
543         for (i = 0; i < RTLX_CHANNELS; i++)
544                 device_destroy(mt_class, MKDEV(major, i));
545
546         return err;
547 }
548
549 static void __exit rtlx_module_exit(void)
550 {
551         int i;
552
553         for (i = 0; i < RTLX_CHANNELS; i++)
554                 device_destroy(mt_class, MKDEV(major, i));
555
556         unregister_chrdev(major, module_name);
557 }
558
559 module_init(rtlx_module_init);
560 module_exit(rtlx_module_exit);
561
562 MODULE_DESCRIPTION("MIPS RTLX");
563 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
564 MODULE_LICENSE("GPL");