Staging: comedi: remove C99 comments in APCI1710_82x54.c
[linux-2.6] / drivers / staging / comedi / drivers.c
1 /*
2     module/drivers.c
3     functions for manipulating drivers
4
5     COMEDI - Linux Control and Measurement Device Interface
6     Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
7
8     This program is free software; you can redistribute it and/or modify
9     it under the terms of the GNU General Public License as published by
10     the Free Software Foundation; either version 2 of the License, or
11     (at your option) any later version.
12
13     This program is distributed in the hope that it will be useful,
14     but WITHOUT ANY WARRANTY; without even the implied warranty of
15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16     GNU General Public License for more details.
17
18     You should have received a copy of the GNU General Public License
19     along with this program; if not, write to the Free Software
20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21
22 */
23
24 #define _GNU_SOURCE
25
26 #define __NO_VERSION__
27 #include "comedi_fops.h"
28 #include <linux/device.h>
29 #include <linux/module.h>
30 #include <linux/pci.h>
31 #include <linux/usb.h>
32 #include <linux/errno.h>
33 #include <linux/kernel.h>
34 #include <linux/sched.h>
35 #include <linux/fcntl.h>
36 #include <linux/delay.h>
37 #include <linux/ioport.h>
38 #include <linux/mm.h>
39 #include <linux/slab.h>
40 #include "comedidev.h"
41 #include "wrapper.h"
42 #include <linux/highmem.h>      /* for SuSE brokenness */
43 #include <linux/vmalloc.h>
44 #include <linux/cdev.h>
45 #include <linux/dma-mapping.h>
46
47 #include <asm/io.h>
48 #include <asm/system.h>
49
50 static int postconfig(struct comedi_device *dev);
51 static int insn_rw_emulate_bits(struct comedi_device *dev, struct comedi_subdevice *s,
52         struct comedi_insn *insn, unsigned int *data);
53 static void *comedi_recognize(struct comedi_driver * driv, const char *name);
54 static void comedi_report_boards(struct comedi_driver *driv);
55 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s);
56 int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
57         unsigned long new_size);
58
59 struct comedi_driver *comedi_drivers;
60
61 int comedi_modprobe(int minor)
62 {
63         return -EINVAL;
64 }
65
66 static void cleanup_device(struct comedi_device *dev)
67 {
68         int i;
69         struct comedi_subdevice *s;
70
71         if (dev->subdevices) {
72                 for (i = 0; i < dev->n_subdevices; i++) {
73                         s = dev->subdevices + i;
74                         comedi_free_subdevice_minor(s);
75                         if (s->async) {
76                                 comedi_buf_alloc(dev, s, 0);
77                                 kfree(s->async);
78                         }
79                 }
80                 kfree(dev->subdevices);
81                 dev->subdevices = NULL;
82                 dev->n_subdevices = 0;
83         }
84         kfree(dev->private);
85         dev->private = NULL;
86         dev->driver = 0;
87         dev->board_name = NULL;
88         dev->board_ptr = NULL;
89         dev->iobase = 0;
90         dev->irq = 0;
91         dev->read_subdev = NULL;
92         dev->write_subdev = NULL;
93         dev->open = NULL;
94         dev->close = NULL;
95         comedi_set_hw_dev(dev, NULL);
96 }
97
98 static void __comedi_device_detach(struct comedi_device *dev)
99 {
100         dev->attached = 0;
101         if (dev->driver) {
102                 dev->driver->detach(dev);
103         } else {
104                 printk("BUG: dev->driver=NULL in comedi_device_detach()\n");
105         }
106         cleanup_device(dev);
107 }
108
109 void comedi_device_detach(struct comedi_device *dev)
110 {
111         if (!dev->attached)
112                 return;
113         __comedi_device_detach(dev);
114 }
115
116 int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
117 {
118         struct comedi_driver *driv;
119         int ret;
120
121         if (dev->attached)
122                 return -EBUSY;
123
124         for (driv = comedi_drivers; driv; driv = driv->next) {
125                 if (!try_module_get(driv->module)) {
126                         printk("comedi: failed to increment module count, skipping\n");
127                         continue;
128                 }
129                 if (driv->num_names) {
130                         dev->board_ptr = comedi_recognize(driv, it->board_name);
131                         if (dev->board_ptr == NULL) {
132                                 module_put(driv->module);
133                                 continue;
134                         }
135                 } else {
136                         if (strcmp(driv->driver_name, it->board_name)) {
137                                 module_put(driv->module);
138                                 continue;
139                         }
140                 }
141                 /* initialize dev->driver here so comedi_error() can be called from attach */
142                 dev->driver = driv;
143                 ret = driv->attach(dev, it);
144                 if (ret < 0) {
145                         module_put(dev->driver->module);
146                         __comedi_device_detach(dev);
147                         return ret;
148                 }
149                 goto attached;
150         }
151
152         /*  recognize has failed if we get here */
153         /*  report valid board names before returning error */
154         for (driv = comedi_drivers; driv; driv = driv->next) {
155                 if (!try_module_get(driv->module)) {
156                         printk("comedi: failed to increment module count\n");
157                         continue;
158                 }
159                 comedi_report_boards(driv);
160                 module_put(driv->module);
161         }
162         return -EIO;
163
164 attached:
165         /* do a little post-config cleanup */
166         ret = postconfig(dev);
167         module_put(dev->driver->module);
168         if (ret < 0) {
169                 __comedi_device_detach(dev);
170                 return ret;
171         }
172
173         if (!dev->board_name) {
174                 printk("BUG: dev->board_name=<%p>\n", dev->board_name);
175                 dev->board_name = "BUG";
176         }
177         smp_wmb();
178         dev->attached = 1;
179
180         return 0;
181 }
182
183 int comedi_driver_register(struct comedi_driver *driver)
184 {
185         driver->next = comedi_drivers;
186         comedi_drivers = driver;
187
188         return 0;
189 }
190
191 int comedi_driver_unregister(struct comedi_driver *driver)
192 {
193         struct comedi_driver *prev;
194         int i;
195
196         /* check for devices using this driver */
197         for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
198                 struct comedi_device_file_info *dev_file_info = comedi_get_device_file_info(i);
199                 struct comedi_device *dev;
200
201                 if(dev_file_info == NULL) continue;
202                 dev = dev_file_info->device;
203
204                 mutex_lock(&dev->mutex);
205                 if (dev->attached && dev->driver == driver) {
206                         if (dev->use_count)
207                                 printk("BUG! detaching device with use_count=%d\n", dev->use_count);
208                         comedi_device_detach(dev);
209                 }
210                 mutex_unlock(&dev->mutex);
211         }
212
213         if (comedi_drivers == driver) {
214                 comedi_drivers = driver->next;
215                 return 0;
216         }
217
218         for (prev = comedi_drivers; prev->next; prev = prev->next) {
219                 if (prev->next == driver) {
220                         prev->next = driver->next;
221                         return 0;
222                 }
223         }
224         return -EINVAL;
225 }
226
227 static int postconfig(struct comedi_device *dev)
228 {
229         int i;
230         struct comedi_subdevice *s;
231         struct comedi_async *async = NULL;
232         int ret;
233
234         for (i = 0; i < dev->n_subdevices; i++) {
235                 s = dev->subdevices + i;
236
237                 if (s->type == COMEDI_SUBD_UNUSED)
238                         continue;
239
240                 if (s->len_chanlist == 0)
241                         s->len_chanlist = 1;
242
243                 if (s->do_cmd) {
244                         BUG_ON((s->subdev_flags & (SDF_CMD_READ |
245                                 SDF_CMD_WRITE)) == 0);
246                         BUG_ON(!s->do_cmdtest);
247
248                         async = kzalloc(sizeof(struct comedi_async), GFP_KERNEL);
249                         if (async == NULL) {
250                                 printk("failed to allocate async struct\n");
251                                 return -ENOMEM;
252                         }
253                         init_waitqueue_head(&async->wait_head);
254                         async->subdevice = s;
255                         s->async = async;
256
257 #define DEFAULT_BUF_MAXSIZE (64*1024)
258 #define DEFAULT_BUF_SIZE (64*1024)
259
260                         async->max_bufsize = DEFAULT_BUF_MAXSIZE;
261
262                         async->prealloc_buf = NULL;
263                         async->prealloc_bufsz = 0;
264                         if (comedi_buf_alloc(dev, s, DEFAULT_BUF_SIZE) < 0) {
265                                 printk("Buffer allocation failed\n");
266                                 return -ENOMEM;
267                         }
268                         if (s->buf_change) {
269                                 ret = s->buf_change(dev, s, DEFAULT_BUF_SIZE);
270                                 if (ret < 0)
271                                         return ret;
272                         }
273                         comedi_alloc_subdevice_minor(dev, s);
274                 }
275
276                 if (!s->range_table && !s->range_table_list)
277                         s->range_table = &range_unknown;
278
279                 if (!s->insn_read && s->insn_bits)
280                         s->insn_read = insn_rw_emulate_bits;
281                 if (!s->insn_write && s->insn_bits)
282                         s->insn_write = insn_rw_emulate_bits;
283
284                 if (!s->insn_read)
285                         s->insn_read = insn_inval;
286                 if (!s->insn_write)
287                         s->insn_write = insn_inval;
288                 if (!s->insn_bits)
289                         s->insn_bits = insn_inval;
290                 if (!s->insn_config)
291                         s->insn_config = insn_inval;
292
293                 if (!s->poll)
294                         s->poll = poll_invalid;
295         }
296
297         return 0;
298 }
299
300 /*  generic recognize function for drivers that register their supported board names */
301 void *comedi_recognize(struct comedi_driver * driv, const char *name)
302 {
303         unsigned i;
304         const char *const *name_ptr = driv->board_name;
305         for (i = 0; i < driv->num_names; i++) {
306                 if (strcmp(*name_ptr, name) == 0)
307                         return (void *)name_ptr;
308                 name_ptr =
309                         (const char *const *)((const char *)name_ptr +
310                         driv->offset);
311         }
312
313         return NULL;
314 }
315
316 void comedi_report_boards(struct comedi_driver *driv)
317 {
318         unsigned int i;
319         const char *const *name_ptr;
320
321         printk("comedi: valid board names for %s driver are:\n",
322                 driv->driver_name);
323
324         name_ptr = driv->board_name;
325         for (i = 0; i < driv->num_names; i++) {
326                 printk(" %s\n", *name_ptr);
327                 name_ptr = (const char **)((char *)name_ptr + driv->offset);
328         }
329
330         if (driv->num_names == 0)
331                 printk(" %s\n", driv->driver_name);
332 }
333
334 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
335 {
336         return -EINVAL;
337 }
338
339 int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
340         struct comedi_insn *insn, unsigned int *data)
341 {
342         return -EINVAL;
343 }
344
345 static int insn_rw_emulate_bits(struct comedi_device *dev, struct comedi_subdevice *s,
346         struct comedi_insn *insn, unsigned int *data)
347 {
348         struct comedi_insn new_insn;
349         int ret;
350         static const unsigned channels_per_bitfield = 32;
351
352         unsigned chan = CR_CHAN(insn->chanspec);
353         const unsigned base_bitfield_channel =
354                 (chan < channels_per_bitfield) ? 0 : chan;
355         unsigned int new_data[2];
356         memset(new_data, 0, sizeof(new_data));
357         memset(&new_insn, 0, sizeof(new_insn));
358         new_insn.insn = INSN_BITS;
359         new_insn.chanspec = base_bitfield_channel;
360         new_insn.n = 2;
361         new_insn.data = new_data;
362         new_insn.subdev = insn->subdev;
363
364         if (insn->insn == INSN_WRITE) {
365                 if (!(s->subdev_flags & SDF_WRITABLE))
366                         return -EINVAL;
367                 new_data[0] = 1 << (chan - base_bitfield_channel);      /* mask */
368                 new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel)) : 0;      /* bits */
369         }
370
371         ret = s->insn_bits(dev, s, &new_insn, new_data);
372         if (ret < 0)
373                 return ret;
374
375         if (insn->insn == INSN_READ) {
376                 data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
377         }
378
379         return 1;
380 }
381
382 static inline unsigned long uvirt_to_kva(pgd_t *pgd, unsigned long adr)
383 {
384         unsigned long ret = 0UL;
385         pmd_t *pmd;
386         pte_t *ptep, pte;
387         pud_t *pud;
388
389         if (!pgd_none(*pgd)) {
390                 pud = pud_offset(pgd, adr);
391                 pmd = pmd_offset(pud, adr);
392                 if (!pmd_none(*pmd)) {
393                         ptep = pte_offset_kernel(pmd, adr);
394                         pte = *ptep;
395                         if (pte_present(pte)) {
396                                 ret = (unsigned long)
397                                         page_address(pte_page(pte));
398                                 ret |= (adr & (PAGE_SIZE - 1));
399                         }
400                 }
401         }
402         return ret;
403 }
404
405 static inline unsigned long kvirt_to_kva(unsigned long adr)
406 {
407         unsigned long va, kva;
408
409         va = adr;
410         kva = uvirt_to_kva(pgd_offset_k(va), va);
411
412         return kva;
413 }
414
415 int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
416         unsigned long new_size)
417 {
418         struct comedi_async *async = s->async;
419
420         /* Round up new_size to multiple of PAGE_SIZE */
421         new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
422
423         /* if no change is required, do nothing */
424         if (async->prealloc_buf && async->prealloc_bufsz == new_size) {
425                 return 0;
426         }
427         /*  deallocate old buffer */
428         if (async->prealloc_buf) {
429                 vunmap(async->prealloc_buf);
430                 async->prealloc_buf = NULL;
431                 async->prealloc_bufsz = 0;
432         }
433         if (async->buf_page_list) {
434                 unsigned i;
435                 for (i = 0; i < async->n_buf_pages; ++i) {
436                         if (async->buf_page_list[i].virt_addr) {
437                                 mem_map_unreserve(virt_to_page(async->
438                                                 buf_page_list[i].virt_addr));
439                                 if (s->async_dma_dir != DMA_NONE) {
440                                         dma_free_coherent(dev->hw_dev,
441                                                 PAGE_SIZE,
442                                                 async->buf_page_list[i].
443                                                 virt_addr,
444                                                 async->buf_page_list[i].
445                                                 dma_addr);
446                                 } else {
447                                         free_page((unsigned long)async->
448                                                 buf_page_list[i].virt_addr);
449                                 }
450                         }
451                 }
452                 vfree(async->buf_page_list);
453                 async->buf_page_list = NULL;
454                 async->n_buf_pages = 0;
455         }
456         /*  allocate new buffer */
457         if (new_size) {
458                 unsigned i = 0;
459                 unsigned n_pages = new_size >> PAGE_SHIFT;
460                 struct page **pages = NULL;
461
462                 async->buf_page_list =
463                         vmalloc(sizeof(struct comedi_buf_page) * n_pages);
464                 if (async->buf_page_list) {
465                         memset(async->buf_page_list, 0,
466                                 sizeof(struct comedi_buf_page) * n_pages);
467                         pages = vmalloc(sizeof(struct page *) * n_pages);
468                 }
469                 if (pages) {
470                         for (i = 0; i < n_pages; i++) {
471                                 if (s->async_dma_dir != DMA_NONE) {
472                                         async->buf_page_list[i].virt_addr =
473                                                 dma_alloc_coherent(dev->hw_dev,
474                                                 PAGE_SIZE,
475                                                 &async->buf_page_list[i].
476                                                 dma_addr,
477                                                 GFP_KERNEL | __GFP_COMP);
478                                 } else {
479                                         async->buf_page_list[i].virt_addr =
480                                                 (void *)
481                                                 get_zeroed_page(GFP_KERNEL);
482                                 }
483                                 if (async->buf_page_list[i].virt_addr == NULL) {
484                                         break;
485                                 }
486                                 mem_map_reserve(virt_to_page(async->
487                                                 buf_page_list[i].virt_addr));
488                                 pages[i] =
489                                         virt_to_page(async->buf_page_list[i].
490                                         virt_addr);
491                         }
492                 }
493                 if (i == n_pages) {
494                         async->prealloc_buf =
495                                 vmap(pages, n_pages, VM_MAP,
496                                 PAGE_KERNEL_NOCACHE);
497                 }
498                 if (pages) {
499                         vfree(pages);
500                 }
501                 if (async->prealloc_buf == NULL) {
502                         /* Some allocation failed above. */
503                         if (async->buf_page_list) {
504                                 for (i = 0; i < n_pages; i++) {
505                                         if (async->buf_page_list[i].virt_addr ==
506                                                 NULL) {
507                                                 break;
508                                         }
509                                         mem_map_unreserve(virt_to_page(async->
510                                                         buf_page_list[i].
511                                                         virt_addr));
512                                         if (s->async_dma_dir != DMA_NONE) {
513                                                 dma_free_coherent(dev->hw_dev,
514                                                         PAGE_SIZE,
515                                                         async->buf_page_list[i].
516                                                         virt_addr,
517                                                         async->buf_page_list[i].
518                                                         dma_addr);
519                                         } else {
520                                                 free_page((unsigned long)async->
521                                                         buf_page_list[i].
522                                                         virt_addr);
523                                         }
524                                 }
525                                 vfree(async->buf_page_list);
526                                 async->buf_page_list = NULL;
527                         }
528                         return -ENOMEM;
529                 }
530                 async->n_buf_pages = n_pages;
531         }
532         async->prealloc_bufsz = new_size;
533
534         return 0;
535 }
536
537 /* munging is applied to data by core as it passes between user
538  * and kernel space */
539 unsigned int comedi_buf_munge(struct comedi_async *async, unsigned int num_bytes)
540 {
541         struct comedi_subdevice *s = async->subdevice;
542         unsigned int count = 0;
543         const unsigned num_sample_bytes = bytes_per_sample(s);
544
545         if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
546                 async->munge_count += num_bytes;
547                 BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
548                 return num_bytes;
549         }
550         /* don't munge partial samples */
551         num_bytes -= num_bytes % num_sample_bytes;
552         while (count < num_bytes) {
553                 int block_size;
554
555                 block_size = num_bytes - count;
556                 if (block_size < 0) {
557                         rt_printk("%s: %s: bug! block_size is negative\n",
558                                 __FILE__, __func__);
559                         break;
560                 }
561                 if ((int)(async->munge_ptr + block_size -
562                                 async->prealloc_bufsz) > 0)
563                         block_size = async->prealloc_bufsz - async->munge_ptr;
564
565                 s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
566                         block_size, async->munge_chan);
567
568                 smp_wmb();      /* barrier insures data is munged in buffer before munge_count is incremented */
569
570                 async->munge_chan += block_size / num_sample_bytes;
571                 async->munge_chan %= async->cmd.chanlist_len;
572                 async->munge_count += block_size;
573                 async->munge_ptr += block_size;
574                 async->munge_ptr %= async->prealloc_bufsz;
575                 count += block_size;
576         }
577         BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
578         return count;
579 }
580
581 unsigned int comedi_buf_write_n_available(struct comedi_async *async)
582 {
583         unsigned int free_end;
584         unsigned int nbytes;
585
586         if (async == NULL)
587                 return 0;
588
589         free_end = async->buf_read_count + async->prealloc_bufsz;
590         nbytes = free_end - async->buf_write_alloc_count;
591         nbytes -= nbytes % bytes_per_sample(async->subdevice);
592         /* barrier insures the read of buf_read_count in this
593            query occurs before any following writes to the buffer which
594            might be based on the return value from this query.
595          */
596         smp_mb();
597         return nbytes;
598 }
599
600 /* allocates chunk for the writer from free buffer space */
601 unsigned int comedi_buf_write_alloc(struct comedi_async *async, unsigned int nbytes)
602 {
603         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
604
605         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0) {
606                 nbytes = free_end - async->buf_write_alloc_count;
607         }
608         async->buf_write_alloc_count += nbytes;
609         /* barrier insures the read of buf_read_count above occurs before
610            we write data to the write-alloc'ed buffer space */
611         smp_mb();
612         return nbytes;
613 }
614
615 /* allocates nothing unless it can completely fulfill the request */
616 unsigned int comedi_buf_write_alloc_strict(struct comedi_async *async,
617         unsigned int nbytes)
618 {
619         unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
620
621         if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0) {
622                 nbytes = 0;
623         }
624         async->buf_write_alloc_count += nbytes;
625         /* barrier insures the read of buf_read_count above occurs before
626            we write data to the write-alloc'ed buffer space */
627         smp_mb();
628         return nbytes;
629 }
630
631 /* transfers a chunk from writer to filled buffer space */
632 unsigned comedi_buf_write_free(struct comedi_async *async, unsigned int nbytes)
633 {
634         if ((int)(async->buf_write_count + nbytes -
635                         async->buf_write_alloc_count) > 0) {
636                 rt_printk
637                         ("comedi: attempted to write-free more bytes than have been write-allocated.\n");
638                 nbytes = async->buf_write_alloc_count - async->buf_write_count;
639         }
640         async->buf_write_count += nbytes;
641         async->buf_write_ptr += nbytes;
642         comedi_buf_munge(async, async->buf_write_count - async->munge_count);
643         if (async->buf_write_ptr >= async->prealloc_bufsz) {
644                 async->buf_write_ptr %= async->prealloc_bufsz;
645         }
646         return nbytes;
647 }
648
649 /* allocates a chunk for the reader from filled (and munged) buffer space */
650 unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes)
651 {
652         if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
653                 0) {
654                 nbytes = async->munge_count - async->buf_read_alloc_count;
655         }
656         async->buf_read_alloc_count += nbytes;
657         /* barrier insures read of munge_count occurs before we actually read
658            data out of buffer */
659         smp_rmb();
660         return nbytes;
661 }
662
663 /* transfers control of a chunk from reader to free buffer space */
664 unsigned comedi_buf_read_free(struct comedi_async *async, unsigned int nbytes)
665 {
666         /*  barrier insures data has been read out of buffer before read count is incremented */
667         smp_mb();
668         if ((int)(async->buf_read_count + nbytes -
669                         async->buf_read_alloc_count) > 0) {
670                 rt_printk
671                         ("comedi: attempted to read-free more bytes than have been read-allocated.\n");
672                 nbytes = async->buf_read_alloc_count - async->buf_read_count;
673         }
674         async->buf_read_count += nbytes;
675         async->buf_read_ptr += nbytes;
676         async->buf_read_ptr %= async->prealloc_bufsz;
677         return nbytes;
678 }
679
680 void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
681         const void *data, unsigned int num_bytes)
682 {
683         unsigned int write_ptr = async->buf_write_ptr + offset;
684
685         if (write_ptr >= async->prealloc_bufsz)
686                 write_ptr %= async->prealloc_bufsz;
687
688         while (num_bytes) {
689                 unsigned int block_size;
690
691                 if (write_ptr + num_bytes > async->prealloc_bufsz)
692                         block_size = async->prealloc_bufsz - write_ptr;
693                 else
694                         block_size = num_bytes;
695
696                 memcpy(async->prealloc_buf + write_ptr, data, block_size);
697
698                 data += block_size;
699                 num_bytes -= block_size;
700
701                 write_ptr = 0;
702         }
703 }
704
705 void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
706         void *dest, unsigned int nbytes)
707 {
708         void *src;
709         unsigned int read_ptr = async->buf_read_ptr + offset;
710
711         if (read_ptr >= async->prealloc_bufsz)
712                 read_ptr %= async->prealloc_bufsz;
713
714         while (nbytes) {
715                 unsigned int block_size;
716
717                 src = async->prealloc_buf + read_ptr;
718
719                 if (nbytes >= async->prealloc_bufsz - read_ptr)
720                         block_size = async->prealloc_bufsz - read_ptr;
721                 else
722                         block_size = nbytes;
723
724                 memcpy(dest, src, block_size);
725                 nbytes -= block_size;
726                 dest += block_size;
727                 read_ptr = 0;
728         }
729 }
730
731 unsigned int comedi_buf_read_n_available(struct comedi_async *async)
732 {
733         unsigned num_bytes;
734
735         if (async == NULL)
736                 return 0;
737         num_bytes = async->munge_count - async->buf_read_count;
738         /* barrier insures the read of munge_count in this
739            query occurs before any following reads of the buffer which
740            might be based on the return value from this query.
741          */
742         smp_rmb();
743         return num_bytes;
744 }
745
746 int comedi_buf_get(struct comedi_async *async, short *x)
747 {
748         unsigned int n = comedi_buf_read_n_available(async);
749
750         if (n < sizeof(short))
751                 return 0;
752         comedi_buf_read_alloc(async, sizeof(short));
753         *x = *(short *) (async->prealloc_buf + async->buf_read_ptr);
754         comedi_buf_read_free(async, sizeof(short));
755         return 1;
756 }
757
758 int comedi_buf_put(struct comedi_async *async, short x)
759 {
760         unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(short));
761
762         if (n < sizeof(short)) {
763                 async->events |= COMEDI_CB_ERROR;
764                 return 0;
765         }
766         *(short *) (async->prealloc_buf + async->buf_write_ptr) = x;
767         comedi_buf_write_free(async, sizeof(short));
768         return 1;
769 }
770
771 void comedi_reset_async_buf(struct comedi_async *async)
772 {
773         async->buf_write_alloc_count = 0;
774         async->buf_write_count = 0;
775         async->buf_read_alloc_count = 0;
776         async->buf_read_count = 0;
777
778         async->buf_write_ptr = 0;
779         async->buf_read_ptr = 0;
780
781         async->cur_chan = 0;
782         async->scan_progress = 0;
783         async->munge_chan = 0;
784         async->munge_count = 0;
785         async->munge_ptr = 0;
786
787         async->events = 0;
788 }
789
790 int comedi_auto_config(struct device *hardware_device, const char *board_name, const int *options, unsigned num_options)
791 {
792         struct comedi_devconfig it;
793         int minor;
794         struct comedi_device_file_info *dev_file_info;
795         int retval;
796         unsigned *private_data = NULL;
797
798         if (!comedi_autoconfig) {
799                 dev_set_drvdata(hardware_device, NULL);
800                 return 0;
801         }
802
803         minor = comedi_alloc_board_minor(hardware_device);
804         if(minor < 0) return minor;
805
806         private_data = kmalloc(sizeof(unsigned), GFP_KERNEL);
807         if (private_data == NULL) {
808                 retval = -ENOMEM;
809                 goto cleanup;
810         }
811         *private_data = minor;
812         dev_set_drvdata(hardware_device, private_data);
813
814         dev_file_info = comedi_get_device_file_info(minor);
815
816         memset(&it, 0, sizeof(it));
817         strncpy(it.board_name, board_name, COMEDI_NAMELEN);
818         it.board_name[COMEDI_NAMELEN - 1] = '\0';
819         BUG_ON(num_options > COMEDI_NDEVCONFOPTS);
820         memcpy(it.options, options, num_options * sizeof(int));
821
822         mutex_lock(&dev_file_info->device->mutex);
823         retval = comedi_device_attach(dev_file_info->device, &it);
824         mutex_unlock(&dev_file_info->device->mutex);
825
826 cleanup:
827         if(retval < 0)
828         {
829                 kfree(private_data);
830                 comedi_free_board_minor(minor);
831         }
832         return retval;
833 }
834
835 void comedi_auto_unconfig(struct device *hardware_device)
836 {
837         unsigned *minor = (unsigned *)dev_get_drvdata(hardware_device);
838         if(minor == NULL) return;
839
840         BUG_ON(*minor >= COMEDI_NUM_BOARD_MINORS);
841
842         comedi_free_board_minor(*minor);
843         dev_set_drvdata(hardware_device, NULL);
844         kfree(minor);
845 }
846
847 int comedi_pci_auto_config(struct pci_dev *pcidev, const char *board_name)
848 {
849         int options[2];
850
851         /*  pci bus */
852         options[0] = pcidev->bus->number;
853         /*  pci slot */
854         options[1] = PCI_SLOT(pcidev->devfn);
855
856         return comedi_auto_config(&pcidev->dev, board_name, options, sizeof(options) / sizeof(options[0]));
857 }
858
859 void comedi_pci_auto_unconfig(struct pci_dev *pcidev)
860 {
861         comedi_auto_unconfig(&pcidev->dev);
862 }
863
864 int comedi_usb_auto_config(struct usb_device *usbdev,
865         const char *board_name)
866 {
867         BUG_ON(usbdev == NULL);
868         return comedi_auto_config(&usbdev->dev, board_name, NULL, 0);
869 }
870
871 void comedi_usb_auto_unconfig(struct usb_device *usbdev)
872 {
873         BUG_ON(usbdev == NULL);
874         comedi_auto_unconfig(&usbdev->dev);
875 }