comedi_fops.c revision 3ffab428f40849ed5f21bcfd7285bdef7902f9ca
1/*
2    comedi/comedi_fops.c
3    comedi kernel module
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#undef DEBUG
25
26#define __NO_VERSION__
27#include "comedi_fops.h"
28#include "comedi_compat32.h"
29
30#include <linux/module.h>
31#include <linux/errno.h>
32#include <linux/kernel.h>
33#include <linux/sched.h>
34#include <linux/fcntl.h>
35#include <linux/delay.h>
36#include <linux/ioport.h>
37#include <linux/mm.h>
38#include <linux/slab.h>
39#include <linux/kmod.h>
40#include <linux/poll.h>
41#include <linux/init.h>
42#include <linux/device.h>
43#include <linux/vmalloc.h>
44#include <linux/fs.h>
45#include "comedidev.h"
46#include <linux/cdev.h>
47#include <linux/stat.h>
48
49#include <linux/io.h>
50#include <linux/uaccess.h>
51
52#include "internal.h"
53
54MODULE_AUTHOR("http://www.comedi.org");
55MODULE_DESCRIPTION("Comedi core module");
56MODULE_LICENSE("GPL");
57
58#ifdef CONFIG_COMEDI_DEBUG
59int comedi_debug;
60EXPORT_SYMBOL(comedi_debug);
61module_param(comedi_debug, int, 0644);
62#endif
63
64int comedi_autoconfig = 1;
65module_param(comedi_autoconfig, bool, 0444);
66
67static int comedi_num_legacy_minors;
68module_param(comedi_num_legacy_minors, int, 0444);
69
70static DEFINE_SPINLOCK(comedi_file_info_table_lock);
71static struct comedi_device_file_info
72*comedi_file_info_table[COMEDI_NUM_MINORS];
73
74static int do_devconfig_ioctl(struct comedi_device *dev,
75			      struct comedi_devconfig __user *arg);
76static int do_bufconfig_ioctl(struct comedi_device *dev,
77			      struct comedi_bufconfig __user *arg);
78static int do_devinfo_ioctl(struct comedi_device *dev,
79			    struct comedi_devinfo __user *arg,
80			    struct file *file);
81static int do_subdinfo_ioctl(struct comedi_device *dev,
82			     struct comedi_subdinfo __user *arg, void *file);
83static int do_chaninfo_ioctl(struct comedi_device *dev,
84			     struct comedi_chaninfo __user *arg);
85static int do_bufinfo_ioctl(struct comedi_device *dev,
86			    struct comedi_bufinfo __user *arg, void *file);
87static int do_cmd_ioctl(struct comedi_device *dev,
88			struct comedi_cmd __user *arg, void *file);
89static int do_lock_ioctl(struct comedi_device *dev, unsigned int arg,
90			 void *file);
91static int do_unlock_ioctl(struct comedi_device *dev, unsigned int arg,
92			   void *file);
93static int do_cancel_ioctl(struct comedi_device *dev, unsigned int arg,
94			   void *file);
95static int do_cmdtest_ioctl(struct comedi_device *dev,
96			    struct comedi_cmd __user *arg, void *file);
97static int do_insnlist_ioctl(struct comedi_device *dev,
98			     struct comedi_insnlist __user *arg, void *file);
99static int do_insn_ioctl(struct comedi_device *dev,
100			 struct comedi_insn __user *arg, void *file);
101static int do_poll_ioctl(struct comedi_device *dev, unsigned int subd,
102			 void *file);
103
104static void do_become_nonbusy(struct comedi_device *dev,
105			      struct comedi_subdevice *s);
106static int do_cancel(struct comedi_device *dev, struct comedi_subdevice *s);
107
108static int comedi_fasync(int fd, struct file *file, int on);
109
110static int is_device_busy(struct comedi_device *dev);
111static int resize_async_buffer(struct comedi_device *dev,
112			       struct comedi_subdevice *s,
113			       struct comedi_async *async, unsigned new_size);
114
115/* declarations for sysfs attribute files */
116static struct device_attribute dev_attr_max_read_buffer_kb;
117static struct device_attribute dev_attr_read_buffer_kb;
118static struct device_attribute dev_attr_max_write_buffer_kb;
119static struct device_attribute dev_attr_write_buffer_kb;
120
121static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
122				  unsigned long arg)
123{
124	const unsigned minor = iminor(file->f_dentry->d_inode);
125	struct comedi_device_file_info *dev_file_info =
126	    comedi_get_device_file_info(minor);
127	struct comedi_device *dev;
128	int rc;
129
130	if (dev_file_info == NULL || dev_file_info->device == NULL)
131		return -ENODEV;
132	dev = dev_file_info->device;
133
134	mutex_lock(&dev->mutex);
135
136	/* Device config is special, because it must work on
137	 * an unconfigured device. */
138	if (cmd == COMEDI_DEVCONFIG) {
139		rc = do_devconfig_ioctl(dev,
140					(struct comedi_devconfig __user *)arg);
141		goto done;
142	}
143
144	if (!dev->attached) {
145		DPRINTK("no driver configured on /dev/comedi%i\n", dev->minor);
146		rc = -ENODEV;
147		goto done;
148	}
149
150	switch (cmd) {
151	case COMEDI_BUFCONFIG:
152		rc = do_bufconfig_ioctl(dev,
153					(struct comedi_bufconfig __user *)arg);
154		break;
155	case COMEDI_DEVINFO:
156		rc = do_devinfo_ioctl(dev, (struct comedi_devinfo __user *)arg,
157				      file);
158		break;
159	case COMEDI_SUBDINFO:
160		rc = do_subdinfo_ioctl(dev,
161				       (struct comedi_subdinfo __user *)arg,
162				       file);
163		break;
164	case COMEDI_CHANINFO:
165		rc = do_chaninfo_ioctl(dev, (void __user *)arg);
166		break;
167	case COMEDI_RANGEINFO:
168		rc = do_rangeinfo_ioctl(dev, (void __user *)arg);
169		break;
170	case COMEDI_BUFINFO:
171		rc = do_bufinfo_ioctl(dev,
172				      (struct comedi_bufinfo __user *)arg,
173				      file);
174		break;
175	case COMEDI_LOCK:
176		rc = do_lock_ioctl(dev, arg, file);
177		break;
178	case COMEDI_UNLOCK:
179		rc = do_unlock_ioctl(dev, arg, file);
180		break;
181	case COMEDI_CANCEL:
182		rc = do_cancel_ioctl(dev, arg, file);
183		break;
184	case COMEDI_CMD:
185		rc = do_cmd_ioctl(dev, (struct comedi_cmd __user *)arg, file);
186		break;
187	case COMEDI_CMDTEST:
188		rc = do_cmdtest_ioctl(dev, (struct comedi_cmd __user *)arg,
189				      file);
190		break;
191	case COMEDI_INSNLIST:
192		rc = do_insnlist_ioctl(dev,
193				       (struct comedi_insnlist __user *)arg,
194				       file);
195		break;
196	case COMEDI_INSN:
197		rc = do_insn_ioctl(dev, (struct comedi_insn __user *)arg,
198				   file);
199		break;
200	case COMEDI_POLL:
201		rc = do_poll_ioctl(dev, arg, file);
202		break;
203	default:
204		rc = -ENOTTY;
205		break;
206	}
207
208done:
209	mutex_unlock(&dev->mutex);
210	return rc;
211}
212
213/*
214	COMEDI_DEVCONFIG
215	device config ioctl
216
217	arg:
218		pointer to devconfig structure
219
220	reads:
221		devconfig structure at arg
222
223	writes:
224		none
225*/
226static int do_devconfig_ioctl(struct comedi_device *dev,
227			      struct comedi_devconfig __user *arg)
228{
229	struct comedi_devconfig it;
230	int ret;
231	unsigned char *aux_data = NULL;
232	int aux_len;
233
234	if (!capable(CAP_SYS_ADMIN))
235		return -EPERM;
236
237	if (arg == NULL) {
238		if (is_device_busy(dev))
239			return -EBUSY;
240		if (dev->attached) {
241			struct module *driver_module = dev->driver->module;
242			comedi_device_detach(dev);
243			module_put(driver_module);
244		}
245		return 0;
246	}
247
248	if (copy_from_user(&it, arg, sizeof(struct comedi_devconfig)))
249		return -EFAULT;
250
251	it.board_name[COMEDI_NAMELEN - 1] = 0;
252
253	if (comedi_aux_data(it.options, 0) &&
254	    it.options[COMEDI_DEVCONF_AUX_DATA_LENGTH]) {
255		int bit_shift;
256		aux_len = it.options[COMEDI_DEVCONF_AUX_DATA_LENGTH];
257		if (aux_len < 0)
258			return -EFAULT;
259
260		aux_data = vmalloc(aux_len);
261		if (!aux_data)
262			return -ENOMEM;
263
264		if (copy_from_user(aux_data,
265				   comedi_aux_data(it.options, 0), aux_len)) {
266			vfree(aux_data);
267			return -EFAULT;
268		}
269		it.options[COMEDI_DEVCONF_AUX_DATA_LO] =
270		    (unsigned long)aux_data;
271		if (sizeof(void *) > sizeof(int)) {
272			bit_shift = sizeof(int) * 8;
273			it.options[COMEDI_DEVCONF_AUX_DATA_HI] =
274			    ((unsigned long)aux_data) >> bit_shift;
275		} else
276			it.options[COMEDI_DEVCONF_AUX_DATA_HI] = 0;
277	}
278
279	ret = comedi_device_attach(dev, &it);
280	if (ret == 0) {
281		if (!try_module_get(dev->driver->module)) {
282			comedi_device_detach(dev);
283			return -ENOSYS;
284		}
285	}
286
287	if (aux_data)
288		vfree(aux_data);
289
290	return ret;
291}
292
293/*
294	COMEDI_BUFCONFIG
295	buffer configuration ioctl
296
297	arg:
298		pointer to bufconfig structure
299
300	reads:
301		bufconfig at arg
302
303	writes:
304		modified bufconfig at arg
305
306*/
307static int do_bufconfig_ioctl(struct comedi_device *dev,
308			      struct comedi_bufconfig __user *arg)
309{
310	struct comedi_bufconfig bc;
311	struct comedi_async *async;
312	struct comedi_subdevice *s;
313	int retval = 0;
314
315	if (copy_from_user(&bc, arg, sizeof(struct comedi_bufconfig)))
316		return -EFAULT;
317
318	if (bc.subdevice >= dev->n_subdevices || bc.subdevice < 0)
319		return -EINVAL;
320
321	s = dev->subdevices + bc.subdevice;
322	async = s->async;
323
324	if (!async) {
325		DPRINTK("subdevice does not have async capability\n");
326		bc.size = 0;
327		bc.maximum_size = 0;
328		goto copyback;
329	}
330
331	if (bc.maximum_size) {
332		if (!capable(CAP_SYS_ADMIN))
333			return -EPERM;
334
335		async->max_bufsize = bc.maximum_size;
336	}
337
338	if (bc.size) {
339		retval = resize_async_buffer(dev, s, async, bc.size);
340		if (retval < 0)
341			return retval;
342	}
343
344	bc.size = async->prealloc_bufsz;
345	bc.maximum_size = async->max_bufsize;
346
347copyback:
348	if (copy_to_user(arg, &bc, sizeof(struct comedi_bufconfig)))
349		return -EFAULT;
350
351	return 0;
352}
353
354/*
355	COMEDI_DEVINFO
356	device info ioctl
357
358	arg:
359		pointer to devinfo structure
360
361	reads:
362		none
363
364	writes:
365		devinfo structure
366
367*/
368static int do_devinfo_ioctl(struct comedi_device *dev,
369			    struct comedi_devinfo __user *arg,
370			    struct file *file)
371{
372	struct comedi_devinfo devinfo;
373	const unsigned minor = iminor(file->f_dentry->d_inode);
374	struct comedi_device_file_info *dev_file_info =
375	    comedi_get_device_file_info(minor);
376	struct comedi_subdevice *read_subdev =
377	    comedi_get_read_subdevice(dev_file_info);
378	struct comedi_subdevice *write_subdev =
379	    comedi_get_write_subdevice(dev_file_info);
380
381	memset(&devinfo, 0, sizeof(devinfo));
382
383	/* fill devinfo structure */
384	devinfo.version_code = COMEDI_VERSION_CODE;
385	devinfo.n_subdevs = dev->n_subdevices;
386	strlcpy(devinfo.driver_name, dev->driver->driver_name, COMEDI_NAMELEN);
387	strlcpy(devinfo.board_name, dev->board_name, COMEDI_NAMELEN);
388
389	if (read_subdev)
390		devinfo.read_subdevice = read_subdev - dev->subdevices;
391	else
392		devinfo.read_subdevice = -1;
393
394	if (write_subdev)
395		devinfo.write_subdevice = write_subdev - dev->subdevices;
396	else
397		devinfo.write_subdevice = -1;
398
399	if (copy_to_user(arg, &devinfo, sizeof(struct comedi_devinfo)))
400		return -EFAULT;
401
402	return 0;
403}
404
405/*
406	COMEDI_SUBDINFO
407	subdevice info ioctl
408
409	arg:
410		pointer to array of subdevice info structures
411
412	reads:
413		none
414
415	writes:
416		array of subdevice info structures at arg
417
418*/
419static int do_subdinfo_ioctl(struct comedi_device *dev,
420			     struct comedi_subdinfo __user *arg, void *file)
421{
422	int ret, i;
423	struct comedi_subdinfo *tmp, *us;
424	struct comedi_subdevice *s;
425
426	tmp =
427	    kcalloc(dev->n_subdevices, sizeof(struct comedi_subdinfo),
428		    GFP_KERNEL);
429	if (!tmp)
430		return -ENOMEM;
431
432	/* fill subdinfo structs */
433	for (i = 0; i < dev->n_subdevices; i++) {
434		s = dev->subdevices + i;
435		us = tmp + i;
436
437		us->type = s->type;
438		us->n_chan = s->n_chan;
439		us->subd_flags = s->subdev_flags;
440		if (comedi_get_subdevice_runflags(s) & SRF_RUNNING)
441			us->subd_flags |= SDF_RUNNING;
442#define TIMER_nanosec 5		/* backwards compatibility */
443		us->timer_type = TIMER_nanosec;
444		us->len_chanlist = s->len_chanlist;
445		us->maxdata = s->maxdata;
446		if (s->range_table) {
447			us->range_type =
448			    (i << 24) | (0 << 16) | (s->range_table->length);
449		} else {
450			us->range_type = 0;	/* XXX */
451		}
452		us->flags = s->flags;
453
454		if (s->busy)
455			us->subd_flags |= SDF_BUSY;
456		if (s->busy == file)
457			us->subd_flags |= SDF_BUSY_OWNER;
458		if (s->lock)
459			us->subd_flags |= SDF_LOCKED;
460		if (s->lock == file)
461			us->subd_flags |= SDF_LOCK_OWNER;
462		if (!s->maxdata && s->maxdata_list)
463			us->subd_flags |= SDF_MAXDATA;
464		if (s->flaglist)
465			us->subd_flags |= SDF_FLAGS;
466		if (s->range_table_list)
467			us->subd_flags |= SDF_RANGETYPE;
468		if (s->do_cmd)
469			us->subd_flags |= SDF_CMD;
470
471		if (s->insn_bits != &insn_inval)
472			us->insn_bits_support = COMEDI_SUPPORTED;
473		else
474			us->insn_bits_support = COMEDI_UNSUPPORTED;
475
476		us->settling_time_0 = s->settling_time_0;
477	}
478
479	ret = copy_to_user(arg, tmp,
480			   dev->n_subdevices * sizeof(struct comedi_subdinfo));
481
482	kfree(tmp);
483
484	return ret ? -EFAULT : 0;
485}
486
487/*
488	COMEDI_CHANINFO
489	subdevice info ioctl
490
491	arg:
492		pointer to chaninfo structure
493
494	reads:
495		chaninfo structure at arg
496
497	writes:
498		arrays at elements of chaninfo structure
499
500*/
501static int do_chaninfo_ioctl(struct comedi_device *dev,
502			     struct comedi_chaninfo __user *arg)
503{
504	struct comedi_subdevice *s;
505	struct comedi_chaninfo it;
506
507	if (copy_from_user(&it, arg, sizeof(struct comedi_chaninfo)))
508		return -EFAULT;
509
510	if (it.subdev >= dev->n_subdevices)
511		return -EINVAL;
512	s = dev->subdevices + it.subdev;
513
514	if (it.maxdata_list) {
515		if (s->maxdata || !s->maxdata_list)
516			return -EINVAL;
517		if (copy_to_user(it.maxdata_list, s->maxdata_list,
518				 s->n_chan * sizeof(unsigned int)))
519			return -EFAULT;
520	}
521
522	if (it.flaglist) {
523		if (!s->flaglist)
524			return -EINVAL;
525		if (copy_to_user(it.flaglist, s->flaglist,
526				 s->n_chan * sizeof(unsigned int)))
527			return -EFAULT;
528	}
529
530	if (it.rangelist) {
531		int i;
532
533		if (!s->range_table_list)
534			return -EINVAL;
535		for (i = 0; i < s->n_chan; i++) {
536			int x;
537
538			x = (dev->minor << 28) | (it.subdev << 24) | (i << 16) |
539			    (s->range_table_list[i]->length);
540			if (put_user(x, it.rangelist + i))
541				return -EFAULT;
542		}
543#if 0
544		if (copy_to_user(it.rangelist, s->range_type_list,
545				 s->n_chan * sizeof(unsigned int)))
546			return -EFAULT;
547#endif
548	}
549
550	return 0;
551}
552
553 /*
554    COMEDI_BUFINFO
555    buffer information ioctl
556
557    arg:
558    pointer to bufinfo structure
559
560    reads:
561    bufinfo at arg
562
563    writes:
564    modified bufinfo at arg
565
566  */
567static int do_bufinfo_ioctl(struct comedi_device *dev,
568			    struct comedi_bufinfo __user *arg, void *file)
569{
570	struct comedi_bufinfo bi;
571	struct comedi_subdevice *s;
572	struct comedi_async *async;
573
574	if (copy_from_user(&bi, arg, sizeof(struct comedi_bufinfo)))
575		return -EFAULT;
576
577	if (bi.subdevice >= dev->n_subdevices || bi.subdevice < 0)
578		return -EINVAL;
579
580	s = dev->subdevices + bi.subdevice;
581
582	if (s->lock && s->lock != file)
583		return -EACCES;
584
585	async = s->async;
586
587	if (!async) {
588		DPRINTK("subdevice does not have async capability\n");
589		bi.buf_write_ptr = 0;
590		bi.buf_read_ptr = 0;
591		bi.buf_write_count = 0;
592		bi.buf_read_count = 0;
593		bi.bytes_read = 0;
594		bi.bytes_written = 0;
595		goto copyback;
596	}
597	if (!s->busy) {
598		bi.bytes_read = 0;
599		bi.bytes_written = 0;
600		goto copyback_position;
601	}
602	if (s->busy != file)
603		return -EACCES;
604
605	if (bi.bytes_read && (s->subdev_flags & SDF_CMD_READ)) {
606		bi.bytes_read = comedi_buf_read_alloc(async, bi.bytes_read);
607		comedi_buf_read_free(async, bi.bytes_read);
608
609		if (!(comedi_get_subdevice_runflags(s) & (SRF_ERROR |
610							  SRF_RUNNING))
611		    && async->buf_write_count == async->buf_read_count) {
612			do_become_nonbusy(dev, s);
613		}
614	}
615
616	if (bi.bytes_written && (s->subdev_flags & SDF_CMD_WRITE)) {
617		bi.bytes_written =
618		    comedi_buf_write_alloc(async, bi.bytes_written);
619		comedi_buf_write_free(async, bi.bytes_written);
620	}
621
622copyback_position:
623	bi.buf_write_count = async->buf_write_count;
624	bi.buf_write_ptr = async->buf_write_ptr;
625	bi.buf_read_count = async->buf_read_count;
626	bi.buf_read_ptr = async->buf_read_ptr;
627
628copyback:
629	if (copy_to_user(arg, &bi, sizeof(struct comedi_bufinfo)))
630		return -EFAULT;
631
632	return 0;
633}
634
635static int parse_insn(struct comedi_device *dev, struct comedi_insn *insn,
636		      unsigned int *data, void *file);
637/*
638 *	COMEDI_INSNLIST
639 *	synchronous instructions
640 *
641 *	arg:
642 *		pointer to sync cmd structure
643 *
644 *	reads:
645 *		sync cmd struct at arg
646 *		instruction list
647 *		data (for writes)
648 *
649 *	writes:
650 *		data (for reads)
651 */
652/* arbitrary limits */
653#define MAX_SAMPLES 256
654static int do_insnlist_ioctl(struct comedi_device *dev,
655			     struct comedi_insnlist __user *arg, void *file)
656{
657	struct comedi_insnlist insnlist;
658	struct comedi_insn *insns = NULL;
659	unsigned int *data = NULL;
660	int i = 0;
661	int ret = 0;
662
663	if (copy_from_user(&insnlist, arg, sizeof(struct comedi_insnlist)))
664		return -EFAULT;
665
666	data = kmalloc(sizeof(unsigned int) * MAX_SAMPLES, GFP_KERNEL);
667	if (!data) {
668		DPRINTK("kmalloc failed\n");
669		ret = -ENOMEM;
670		goto error;
671	}
672
673	insns =
674	    kmalloc(sizeof(struct comedi_insn) * insnlist.n_insns, GFP_KERNEL);
675	if (!insns) {
676		DPRINTK("kmalloc failed\n");
677		ret = -ENOMEM;
678		goto error;
679	}
680
681	if (copy_from_user(insns, insnlist.insns,
682			   sizeof(struct comedi_insn) * insnlist.n_insns)) {
683		DPRINTK("copy_from_user failed\n");
684		ret = -EFAULT;
685		goto error;
686	}
687
688	for (i = 0; i < insnlist.n_insns; i++) {
689		if (insns[i].n > MAX_SAMPLES) {
690			DPRINTK("number of samples too large\n");
691			ret = -EINVAL;
692			goto error;
693		}
694		if (insns[i].insn & INSN_MASK_WRITE) {
695			if (copy_from_user(data, insns[i].data,
696					   insns[i].n * sizeof(unsigned int))) {
697				DPRINTK("copy_from_user failed\n");
698				ret = -EFAULT;
699				goto error;
700			}
701		}
702		ret = parse_insn(dev, insns + i, data, file);
703		if (ret < 0)
704			goto error;
705		if (insns[i].insn & INSN_MASK_READ) {
706			if (copy_to_user(insns[i].data, data,
707					 insns[i].n * sizeof(unsigned int))) {
708				DPRINTK("copy_to_user failed\n");
709				ret = -EFAULT;
710				goto error;
711			}
712		}
713		if (need_resched())
714			schedule();
715	}
716
717error:
718	kfree(insns);
719	kfree(data);
720
721	if (ret < 0)
722		return ret;
723	return i;
724}
725
726static int check_insn_config_length(struct comedi_insn *insn,
727				    unsigned int *data)
728{
729	if (insn->n < 1)
730		return -EINVAL;
731
732	switch (data[0]) {
733	case INSN_CONFIG_DIO_OUTPUT:
734	case INSN_CONFIG_DIO_INPUT:
735	case INSN_CONFIG_DISARM:
736	case INSN_CONFIG_RESET:
737		if (insn->n == 1)
738			return 0;
739		break;
740	case INSN_CONFIG_ARM:
741	case INSN_CONFIG_DIO_QUERY:
742	case INSN_CONFIG_BLOCK_SIZE:
743	case INSN_CONFIG_FILTER:
744	case INSN_CONFIG_SERIAL_CLOCK:
745	case INSN_CONFIG_BIDIRECTIONAL_DATA:
746	case INSN_CONFIG_ALT_SOURCE:
747	case INSN_CONFIG_SET_COUNTER_MODE:
748	case INSN_CONFIG_8254_READ_STATUS:
749	case INSN_CONFIG_SET_ROUTING:
750	case INSN_CONFIG_GET_ROUTING:
751	case INSN_CONFIG_GET_PWM_STATUS:
752	case INSN_CONFIG_PWM_SET_PERIOD:
753	case INSN_CONFIG_PWM_GET_PERIOD:
754		if (insn->n == 2)
755			return 0;
756		break;
757	case INSN_CONFIG_SET_GATE_SRC:
758	case INSN_CONFIG_GET_GATE_SRC:
759	case INSN_CONFIG_SET_CLOCK_SRC:
760	case INSN_CONFIG_GET_CLOCK_SRC:
761	case INSN_CONFIG_SET_OTHER_SRC:
762	case INSN_CONFIG_GET_COUNTER_STATUS:
763	case INSN_CONFIG_PWM_SET_H_BRIDGE:
764	case INSN_CONFIG_PWM_GET_H_BRIDGE:
765	case INSN_CONFIG_GET_HARDWARE_BUFFER_SIZE:
766		if (insn->n == 3)
767			return 0;
768		break;
769	case INSN_CONFIG_PWM_OUTPUT:
770	case INSN_CONFIG_ANALOG_TRIG:
771		if (insn->n == 5)
772			return 0;
773		break;
774		/* by default we allow the insn since we don't have checks for
775		 * all possible cases yet */
776	default:
777		printk(KERN_WARNING
778		       "comedi: no check for data length of config insn id "
779		       "%i is implemented.\n"
780		       " Add a check to %s in %s.\n"
781		       " Assuming n=%i is correct.\n", data[0], __func__,
782		       __FILE__, insn->n);
783		return 0;
784		break;
785	}
786	return -EINVAL;
787}
788
789static int parse_insn(struct comedi_device *dev, struct comedi_insn *insn,
790		      unsigned int *data, void *file)
791{
792	struct comedi_subdevice *s;
793	int ret = 0;
794	int i;
795
796	if (insn->insn & INSN_MASK_SPECIAL) {
797		/* a non-subdevice instruction */
798
799		switch (insn->insn) {
800		case INSN_GTOD:
801			{
802				struct timeval tv;
803
804				if (insn->n != 2) {
805					ret = -EINVAL;
806					break;
807				}
808
809				do_gettimeofday(&tv);
810				data[0] = tv.tv_sec;
811				data[1] = tv.tv_usec;
812				ret = 2;
813
814				break;
815			}
816		case INSN_WAIT:
817			if (insn->n != 1 || data[0] >= 100000) {
818				ret = -EINVAL;
819				break;
820			}
821			udelay(data[0] / 1000);
822			ret = 1;
823			break;
824		case INSN_INTTRIG:
825			if (insn->n != 1) {
826				ret = -EINVAL;
827				break;
828			}
829			if (insn->subdev >= dev->n_subdevices) {
830				DPRINTK("%d not usable subdevice\n",
831					insn->subdev);
832				ret = -EINVAL;
833				break;
834			}
835			s = dev->subdevices + insn->subdev;
836			if (!s->async) {
837				DPRINTK("no async\n");
838				ret = -EINVAL;
839				break;
840			}
841			if (!s->async->inttrig) {
842				DPRINTK("no inttrig\n");
843				ret = -EAGAIN;
844				break;
845			}
846			ret = s->async->inttrig(dev, s, insn->data[0]);
847			if (ret >= 0)
848				ret = 1;
849			break;
850		default:
851			DPRINTK("invalid insn\n");
852			ret = -EINVAL;
853			break;
854		}
855	} else {
856		/* a subdevice instruction */
857		unsigned int maxdata;
858
859		if (insn->subdev >= dev->n_subdevices) {
860			DPRINTK("subdevice %d out of range\n", insn->subdev);
861			ret = -EINVAL;
862			goto out;
863		}
864		s = dev->subdevices + insn->subdev;
865
866		if (s->type == COMEDI_SUBD_UNUSED) {
867			DPRINTK("%d not usable subdevice\n", insn->subdev);
868			ret = -EIO;
869			goto out;
870		}
871
872		/* are we locked? (ioctl lock) */
873		if (s->lock && s->lock != file) {
874			DPRINTK("device locked\n");
875			ret = -EACCES;
876			goto out;
877		}
878
879		ret = comedi_check_chanlist(s, 1, &insn->chanspec);
880		if (ret < 0) {
881			ret = -EINVAL;
882			DPRINTK("bad chanspec\n");
883			goto out;
884		}
885
886		if (s->busy) {
887			ret = -EBUSY;
888			goto out;
889		}
890		/* This looks arbitrary.  It is. */
891		s->busy = &parse_insn;
892		switch (insn->insn) {
893		case INSN_READ:
894			ret = s->insn_read(dev, s, insn, data);
895			break;
896		case INSN_WRITE:
897			maxdata = s->maxdata_list
898			    ? s->maxdata_list[CR_CHAN(insn->chanspec)]
899			    : s->maxdata;
900			for (i = 0; i < insn->n; ++i) {
901				if (data[i] > maxdata) {
902					ret = -EINVAL;
903					DPRINTK("bad data value(s)\n");
904					break;
905				}
906			}
907			if (ret == 0)
908				ret = s->insn_write(dev, s, insn, data);
909			break;
910		case INSN_BITS:
911			if (insn->n != 2) {
912				ret = -EINVAL;
913			} else {
914				/* Most drivers ignore the base channel in
915				 * insn->chanspec.  Fix this here if
916				 * the subdevice has <= 32 channels.  */
917				unsigned int shift;
918				unsigned int orig_mask;
919
920				orig_mask = data[0];
921				if (s->n_chan <= 32) {
922					shift = CR_CHAN(insn->chanspec);
923					if (shift > 0) {
924						insn->chanspec = 0;
925						data[0] <<= shift;
926						data[1] <<= shift;
927					}
928				} else
929					shift = 0;
930				ret = s->insn_bits(dev, s, insn, data);
931				data[0] = orig_mask;
932				if (shift > 0)
933					data[1] >>= shift;
934			}
935			break;
936		case INSN_CONFIG:
937			ret = check_insn_config_length(insn, data);
938			if (ret)
939				break;
940			ret = s->insn_config(dev, s, insn, data);
941			break;
942		default:
943			ret = -EINVAL;
944			break;
945		}
946
947		s->busy = NULL;
948	}
949
950out:
951	return ret;
952}
953
954/*
955 *	COMEDI_INSN
956 *	synchronous instructions
957 *
958 *	arg:
959 *		pointer to insn
960 *
961 *	reads:
962 *		struct comedi_insn struct at arg
963 *		data (for writes)
964 *
965 *	writes:
966 *		data (for reads)
967 */
968static int do_insn_ioctl(struct comedi_device *dev,
969			 struct comedi_insn __user *arg, void *file)
970{
971	struct comedi_insn insn;
972	unsigned int *data = NULL;
973	int ret = 0;
974
975	data = kmalloc(sizeof(unsigned int) * MAX_SAMPLES, GFP_KERNEL);
976	if (!data) {
977		ret = -ENOMEM;
978		goto error;
979	}
980
981	if (copy_from_user(&insn, arg, sizeof(struct comedi_insn))) {
982		ret = -EFAULT;
983		goto error;
984	}
985
986	/* This is where the behavior of insn and insnlist deviate. */
987	if (insn.n > MAX_SAMPLES)
988		insn.n = MAX_SAMPLES;
989	if (insn.insn & INSN_MASK_WRITE) {
990		if (copy_from_user(data,
991				   insn.data,
992				   insn.n * sizeof(unsigned int))) {
993			ret = -EFAULT;
994			goto error;
995		}
996	}
997	ret = parse_insn(dev, &insn, data, file);
998	if (ret < 0)
999		goto error;
1000	if (insn.insn & INSN_MASK_READ) {
1001		if (copy_to_user(insn.data,
1002				 data,
1003				 insn.n * sizeof(unsigned int))) {
1004			ret = -EFAULT;
1005			goto error;
1006		}
1007	}
1008	ret = insn.n;
1009
1010error:
1011	kfree(data);
1012
1013	return ret;
1014}
1015
1016static void comedi_set_subdevice_runflags(struct comedi_subdevice *s,
1017					  unsigned mask, unsigned bits)
1018{
1019	unsigned long flags;
1020
1021	spin_lock_irqsave(&s->spin_lock, flags);
1022	s->runflags &= ~mask;
1023	s->runflags |= (bits & mask);
1024	spin_unlock_irqrestore(&s->spin_lock, flags);
1025}
1026
1027static int do_cmd_ioctl(struct comedi_device *dev,
1028			struct comedi_cmd __user *cmd, void *file)
1029{
1030	struct comedi_cmd user_cmd;
1031	struct comedi_subdevice *s;
1032	struct comedi_async *async;
1033	int ret = 0;
1034	unsigned int __user *chanlist_saver = NULL;
1035
1036	if (copy_from_user(&user_cmd, cmd, sizeof(struct comedi_cmd))) {
1037		DPRINTK("bad cmd address\n");
1038		return -EFAULT;
1039	}
1040	/* save user's chanlist pointer so it can be restored later */
1041	chanlist_saver = user_cmd.chanlist;
1042
1043	if (user_cmd.subdev >= dev->n_subdevices) {
1044		DPRINTK("%d no such subdevice\n", user_cmd.subdev);
1045		return -ENODEV;
1046	}
1047
1048	s = dev->subdevices + user_cmd.subdev;
1049	async = s->async;
1050
1051	if (s->type == COMEDI_SUBD_UNUSED) {
1052		DPRINTK("%d not valid subdevice\n", user_cmd.subdev);
1053		return -EIO;
1054	}
1055
1056	if (!s->do_cmd || !s->do_cmdtest || !s->async) {
1057		DPRINTK("subdevice %i does not support commands\n",
1058			user_cmd.subdev);
1059		return -EIO;
1060	}
1061
1062	/* are we locked? (ioctl lock) */
1063	if (s->lock && s->lock != file) {
1064		DPRINTK("subdevice locked\n");
1065		return -EACCES;
1066	}
1067
1068	/* are we busy? */
1069	if (s->busy) {
1070		DPRINTK("subdevice busy\n");
1071		return -EBUSY;
1072	}
1073	s->busy = file;
1074
1075	/* make sure channel/gain list isn't too long */
1076	if (user_cmd.chanlist_len > s->len_chanlist) {
1077		DPRINTK("channel/gain list too long %u > %d\n",
1078			user_cmd.chanlist_len, s->len_chanlist);
1079		ret = -EINVAL;
1080		goto cleanup;
1081	}
1082
1083	/* make sure channel/gain list isn't too short */
1084	if (user_cmd.chanlist_len < 1) {
1085		DPRINTK("channel/gain list too short %u < 1\n",
1086			user_cmd.chanlist_len);
1087		ret = -EINVAL;
1088		goto cleanup;
1089	}
1090
1091	kfree(async->cmd.chanlist);
1092	async->cmd = user_cmd;
1093	async->cmd.data = NULL;
1094	/* load channel/gain list */
1095	async->cmd.chanlist =
1096	    kmalloc(async->cmd.chanlist_len * sizeof(int), GFP_KERNEL);
1097	if (!async->cmd.chanlist) {
1098		DPRINTK("allocation failed\n");
1099		ret = -ENOMEM;
1100		goto cleanup;
1101	}
1102
1103	if (copy_from_user(async->cmd.chanlist, user_cmd.chanlist,
1104			   async->cmd.chanlist_len * sizeof(int))) {
1105		DPRINTK("fault reading chanlist\n");
1106		ret = -EFAULT;
1107		goto cleanup;
1108	}
1109
1110	/* make sure each element in channel/gain list is valid */
1111	ret = comedi_check_chanlist(s,
1112				    async->cmd.chanlist_len,
1113				    async->cmd.chanlist);
1114	if (ret < 0) {
1115		DPRINTK("bad chanlist\n");
1116		goto cleanup;
1117	}
1118
1119	ret = s->do_cmdtest(dev, s, &async->cmd);
1120
1121	if (async->cmd.flags & TRIG_BOGUS || ret) {
1122		DPRINTK("test returned %d\n", ret);
1123		user_cmd = async->cmd;
1124		/* restore chanlist pointer before copying back */
1125		user_cmd.chanlist = chanlist_saver;
1126		user_cmd.data = NULL;
1127		if (copy_to_user(cmd, &user_cmd, sizeof(struct comedi_cmd))) {
1128			DPRINTK("fault writing cmd\n");
1129			ret = -EFAULT;
1130			goto cleanup;
1131		}
1132		ret = -EAGAIN;
1133		goto cleanup;
1134	}
1135
1136	if (!async->prealloc_bufsz) {
1137		ret = -ENOMEM;
1138		DPRINTK("no buffer (?)\n");
1139		goto cleanup;
1140	}
1141
1142	comedi_reset_async_buf(async);
1143
1144	async->cb_mask =
1145	    COMEDI_CB_EOA | COMEDI_CB_BLOCK | COMEDI_CB_ERROR |
1146	    COMEDI_CB_OVERFLOW;
1147	if (async->cmd.flags & TRIG_WAKE_EOS)
1148		async->cb_mask |= COMEDI_CB_EOS;
1149
1150	comedi_set_subdevice_runflags(s, ~0, SRF_USER | SRF_RUNNING);
1151
1152	ret = s->do_cmd(dev, s);
1153	if (ret == 0)
1154		return 0;
1155
1156cleanup:
1157	do_become_nonbusy(dev, s);
1158
1159	return ret;
1160}
1161
1162/*
1163	COMEDI_CMDTEST
1164	command testing ioctl
1165
1166	arg:
1167		pointer to cmd structure
1168
1169	reads:
1170		cmd structure at arg
1171		channel/range list
1172
1173	writes:
1174		modified cmd structure at arg
1175
1176*/
1177static int do_cmdtest_ioctl(struct comedi_device *dev,
1178			    struct comedi_cmd __user *arg, void *file)
1179{
1180	struct comedi_cmd user_cmd;
1181	struct comedi_subdevice *s;
1182	int ret = 0;
1183	unsigned int *chanlist = NULL;
1184	unsigned int __user *chanlist_saver = NULL;
1185
1186	if (copy_from_user(&user_cmd, arg, sizeof(struct comedi_cmd))) {
1187		DPRINTK("bad cmd address\n");
1188		return -EFAULT;
1189	}
1190	/* save user's chanlist pointer so it can be restored later */
1191	chanlist_saver = user_cmd.chanlist;
1192
1193	if (user_cmd.subdev >= dev->n_subdevices) {
1194		DPRINTK("%d no such subdevice\n", user_cmd.subdev);
1195		return -ENODEV;
1196	}
1197
1198	s = dev->subdevices + user_cmd.subdev;
1199	if (s->type == COMEDI_SUBD_UNUSED) {
1200		DPRINTK("%d not valid subdevice\n", user_cmd.subdev);
1201		return -EIO;
1202	}
1203
1204	if (!s->do_cmd || !s->do_cmdtest) {
1205		DPRINTK("subdevice %i does not support commands\n",
1206			user_cmd.subdev);
1207		return -EIO;
1208	}
1209
1210	/* make sure channel/gain list isn't too long */
1211	if (user_cmd.chanlist_len > s->len_chanlist) {
1212		DPRINTK("channel/gain list too long %d > %d\n",
1213			user_cmd.chanlist_len, s->len_chanlist);
1214		ret = -EINVAL;
1215		goto cleanup;
1216	}
1217
1218	/* load channel/gain list */
1219	if (user_cmd.chanlist) {
1220		chanlist =
1221		    kmalloc(user_cmd.chanlist_len * sizeof(int), GFP_KERNEL);
1222		if (!chanlist) {
1223			DPRINTK("allocation failed\n");
1224			ret = -ENOMEM;
1225			goto cleanup;
1226		}
1227
1228		if (copy_from_user(chanlist, user_cmd.chanlist,
1229				   user_cmd.chanlist_len * sizeof(int))) {
1230			DPRINTK("fault reading chanlist\n");
1231			ret = -EFAULT;
1232			goto cleanup;
1233		}
1234
1235		/* make sure each element in channel/gain list is valid */
1236		ret = comedi_check_chanlist(s, user_cmd.chanlist_len, chanlist);
1237		if (ret < 0) {
1238			DPRINTK("bad chanlist\n");
1239			goto cleanup;
1240		}
1241
1242		user_cmd.chanlist = chanlist;
1243	}
1244
1245	ret = s->do_cmdtest(dev, s, &user_cmd);
1246
1247	/* restore chanlist pointer before copying back */
1248	user_cmd.chanlist = chanlist_saver;
1249
1250	if (copy_to_user(arg, &user_cmd, sizeof(struct comedi_cmd))) {
1251		DPRINTK("bad cmd address\n");
1252		ret = -EFAULT;
1253		goto cleanup;
1254	}
1255cleanup:
1256	kfree(chanlist);
1257
1258	return ret;
1259}
1260
1261/*
1262	COMEDI_LOCK
1263	lock subdevice
1264
1265	arg:
1266		subdevice number
1267
1268	reads:
1269		none
1270
1271	writes:
1272		none
1273
1274*/
1275
1276static int do_lock_ioctl(struct comedi_device *dev, unsigned int arg,
1277			 void *file)
1278{
1279	int ret = 0;
1280	unsigned long flags;
1281	struct comedi_subdevice *s;
1282
1283	if (arg >= dev->n_subdevices)
1284		return -EINVAL;
1285	s = dev->subdevices + arg;
1286
1287	spin_lock_irqsave(&s->spin_lock, flags);
1288	if (s->busy || s->lock)
1289		ret = -EBUSY;
1290	else
1291		s->lock = file;
1292	spin_unlock_irqrestore(&s->spin_lock, flags);
1293
1294#if 0
1295	if (ret < 0)
1296		return ret;
1297
1298	if (s->lock_f)
1299		ret = s->lock_f(dev, s);
1300#endif
1301
1302	return ret;
1303}
1304
1305/*
1306	COMEDI_UNLOCK
1307	unlock subdevice
1308
1309	arg:
1310		subdevice number
1311
1312	reads:
1313		none
1314
1315	writes:
1316		none
1317
1318	This function isn't protected by the semaphore, since
1319	we already own the lock.
1320*/
1321static int do_unlock_ioctl(struct comedi_device *dev, unsigned int arg,
1322			   void *file)
1323{
1324	struct comedi_subdevice *s;
1325
1326	if (arg >= dev->n_subdevices)
1327		return -EINVAL;
1328	s = dev->subdevices + arg;
1329
1330	if (s->busy)
1331		return -EBUSY;
1332
1333	if (s->lock && s->lock != file)
1334		return -EACCES;
1335
1336	if (s->lock == file) {
1337#if 0
1338		if (s->unlock)
1339			s->unlock(dev, s);
1340#endif
1341
1342		s->lock = NULL;
1343	}
1344
1345	return 0;
1346}
1347
1348/*
1349	COMEDI_CANCEL
1350	cancel acquisition ioctl
1351
1352	arg:
1353		subdevice number
1354
1355	reads:
1356		nothing
1357
1358	writes:
1359		nothing
1360
1361*/
1362static int do_cancel_ioctl(struct comedi_device *dev, unsigned int arg,
1363			   void *file)
1364{
1365	struct comedi_subdevice *s;
1366
1367	if (arg >= dev->n_subdevices)
1368		return -EINVAL;
1369	s = dev->subdevices + arg;
1370	if (s->async == NULL)
1371		return -EINVAL;
1372
1373	if (s->lock && s->lock != file)
1374		return -EACCES;
1375
1376	if (!s->busy)
1377		return 0;
1378
1379	if (s->busy != file)
1380		return -EBUSY;
1381
1382	return do_cancel(dev, s);
1383}
1384
1385/*
1386	COMEDI_POLL ioctl
1387	instructs driver to synchronize buffers
1388
1389	arg:
1390		subdevice number
1391
1392	reads:
1393		nothing
1394
1395	writes:
1396		nothing
1397
1398*/
1399static int do_poll_ioctl(struct comedi_device *dev, unsigned int arg,
1400			 void *file)
1401{
1402	struct comedi_subdevice *s;
1403
1404	if (arg >= dev->n_subdevices)
1405		return -EINVAL;
1406	s = dev->subdevices + arg;
1407
1408	if (s->lock && s->lock != file)
1409		return -EACCES;
1410
1411	if (!s->busy)
1412		return 0;
1413
1414	if (s->busy != file)
1415		return -EBUSY;
1416
1417	if (s->poll)
1418		return s->poll(dev, s);
1419
1420	return -EINVAL;
1421}
1422
1423static int do_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
1424{
1425	int ret = 0;
1426
1427	if ((comedi_get_subdevice_runflags(s) & SRF_RUNNING) && s->cancel)
1428		ret = s->cancel(dev, s);
1429
1430	do_become_nonbusy(dev, s);
1431
1432	return ret;
1433}
1434
1435static void comedi_unmap(struct vm_area_struct *area)
1436{
1437	struct comedi_async *async;
1438	struct comedi_device *dev;
1439
1440	async = area->vm_private_data;
1441	dev = async->subdevice->device;
1442
1443	mutex_lock(&dev->mutex);
1444	async->mmap_count--;
1445	mutex_unlock(&dev->mutex);
1446}
1447
1448static struct vm_operations_struct comedi_vm_ops = {
1449	.close = comedi_unmap,
1450};
1451
1452static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
1453{
1454	const unsigned minor = iminor(file->f_dentry->d_inode);
1455	struct comedi_async *async = NULL;
1456	unsigned long start = vma->vm_start;
1457	unsigned long size;
1458	int n_pages;
1459	int i;
1460	int retval;
1461	struct comedi_subdevice *s;
1462	struct comedi_device_file_info *dev_file_info;
1463	struct comedi_device *dev;
1464
1465	dev_file_info = comedi_get_device_file_info(minor);
1466	if (dev_file_info == NULL)
1467	        return -ENODEV;
1468	dev = dev_file_info->device;
1469	if (dev == NULL)
1470	        return -ENODEV;
1471
1472	mutex_lock(&dev->mutex);
1473	if (!dev->attached) {
1474		DPRINTK("no driver configured on comedi%i\n", dev->minor);
1475		retval = -ENODEV;
1476		goto done;
1477	}
1478	if (vma->vm_flags & VM_WRITE)
1479		s = comedi_get_write_subdevice(dev_file_info);
1480	else
1481		s = comedi_get_read_subdevice(dev_file_info);
1482
1483	if (s == NULL) {
1484		retval = -EINVAL;
1485		goto done;
1486	}
1487	async = s->async;
1488	if (async == NULL) {
1489		retval = -EINVAL;
1490		goto done;
1491	}
1492
1493	if (vma->vm_pgoff != 0) {
1494		DPRINTK("comedi: mmap() offset must be 0.\n");
1495		retval = -EINVAL;
1496		goto done;
1497	}
1498
1499	size = vma->vm_end - vma->vm_start;
1500	if (size > async->prealloc_bufsz) {
1501		retval = -EFAULT;
1502		goto done;
1503	}
1504	if (size & (~PAGE_MASK)) {
1505		retval = -EFAULT;
1506		goto done;
1507	}
1508
1509	n_pages = size >> PAGE_SHIFT;
1510	for (i = 0; i < n_pages; ++i) {
1511		if (remap_pfn_range(vma, start,
1512				    page_to_pfn(virt_to_page
1513						(async->buf_page_list
1514						 [i].virt_addr)), PAGE_SIZE,
1515				    PAGE_SHARED)) {
1516			retval = -EAGAIN;
1517			goto done;
1518		}
1519		start += PAGE_SIZE;
1520	}
1521
1522	vma->vm_ops = &comedi_vm_ops;
1523	vma->vm_private_data = async;
1524
1525	async->mmap_count++;
1526
1527	retval = 0;
1528done:
1529	mutex_unlock(&dev->mutex);
1530	return retval;
1531}
1532
1533static unsigned int comedi_poll(struct file *file, poll_table * wait)
1534{
1535	unsigned int mask = 0;
1536	const unsigned minor = iminor(file->f_dentry->d_inode);
1537	struct comedi_subdevice *read_subdev;
1538	struct comedi_subdevice *write_subdev;
1539	struct comedi_device_file_info *dev_file_info;
1540	struct comedi_device *dev;
1541	dev_file_info = comedi_get_device_file_info(minor);
1542
1543	if (dev_file_info == NULL)
1544	        return -ENODEV;
1545	dev = dev_file_info->device;
1546	if (dev == NULL)
1547	        return -ENODEV;
1548
1549	mutex_lock(&dev->mutex);
1550	if (!dev->attached) {
1551		DPRINTK("no driver configured on comedi%i\n", dev->minor);
1552		mutex_unlock(&dev->mutex);
1553		return 0;
1554	}
1555
1556	mask = 0;
1557	read_subdev = comedi_get_read_subdevice(dev_file_info);
1558	if (read_subdev) {
1559		poll_wait(file, &read_subdev->async->wait_head, wait);
1560		if (!read_subdev->busy
1561		    || comedi_buf_read_n_available(read_subdev->async) > 0
1562		    || !(comedi_get_subdevice_runflags(read_subdev) &
1563			 SRF_RUNNING)) {
1564			mask |= POLLIN | POLLRDNORM;
1565		}
1566	}
1567	write_subdev = comedi_get_write_subdevice(dev_file_info);
1568	if (write_subdev) {
1569		poll_wait(file, &write_subdev->async->wait_head, wait);
1570		comedi_buf_write_alloc(write_subdev->async,
1571				       write_subdev->async->prealloc_bufsz);
1572		if (!write_subdev->busy
1573		    || !(comedi_get_subdevice_runflags(write_subdev) &
1574			 SRF_RUNNING)
1575		    || comedi_buf_write_n_allocated(write_subdev->async) >=
1576		    bytes_per_sample(write_subdev->async->subdevice)) {
1577			mask |= POLLOUT | POLLWRNORM;
1578		}
1579	}
1580
1581	mutex_unlock(&dev->mutex);
1582	return mask;
1583}
1584
1585static ssize_t comedi_write(struct file *file, const char __user *buf,
1586			    size_t nbytes, loff_t *offset)
1587{
1588	struct comedi_subdevice *s;
1589	struct comedi_async *async;
1590	int n, m, count = 0, retval = 0;
1591	DECLARE_WAITQUEUE(wait, current);
1592	const unsigned minor = iminor(file->f_dentry->d_inode);
1593	struct comedi_device_file_info *dev_file_info;
1594	struct comedi_device *dev;
1595	dev_file_info = comedi_get_device_file_info(minor);
1596
1597	if (dev_file_info == NULL)
1598	        return -ENODEV;
1599	dev = dev_file_info->device;
1600	if (dev == NULL)
1601	        return -ENODEV;
1602
1603	if (!dev->attached) {
1604		DPRINTK("no driver configured on comedi%i\n", dev->minor);
1605		retval = -ENODEV;
1606		goto done;
1607	}
1608
1609	s = comedi_get_write_subdevice(dev_file_info);
1610	if (s == NULL) {
1611		retval = -EIO;
1612		goto done;
1613	}
1614	async = s->async;
1615
1616	if (!nbytes) {
1617		retval = 0;
1618		goto done;
1619	}
1620	if (!s->busy) {
1621		retval = 0;
1622		goto done;
1623	}
1624	if (s->busy != file) {
1625		retval = -EACCES;
1626		goto done;
1627	}
1628	add_wait_queue(&async->wait_head, &wait);
1629	while (nbytes > 0 && !retval) {
1630		set_current_state(TASK_INTERRUPTIBLE);
1631
1632		if (!(comedi_get_subdevice_runflags(s) & SRF_RUNNING)) {
1633			if (count == 0) {
1634				if (comedi_get_subdevice_runflags(s) &
1635					SRF_ERROR) {
1636					retval = -EPIPE;
1637				} else {
1638					retval = 0;
1639				}
1640				do_become_nonbusy(dev, s);
1641			}
1642			break;
1643		}
1644
1645		n = nbytes;
1646
1647		m = n;
1648		if (async->buf_write_ptr + m > async->prealloc_bufsz)
1649			m = async->prealloc_bufsz - async->buf_write_ptr;
1650		comedi_buf_write_alloc(async, async->prealloc_bufsz);
1651		if (m > comedi_buf_write_n_allocated(async))
1652			m = comedi_buf_write_n_allocated(async);
1653		if (m < n)
1654			n = m;
1655
1656		if (n == 0) {
1657			if (file->f_flags & O_NONBLOCK) {
1658				retval = -EAGAIN;
1659				break;
1660			}
1661			if (signal_pending(current)) {
1662				retval = -ERESTARTSYS;
1663				break;
1664			}
1665			schedule();
1666			if (!s->busy)
1667				break;
1668			if (s->busy != file) {
1669				retval = -EACCES;
1670				break;
1671			}
1672			continue;
1673		}
1674
1675		m = copy_from_user(async->prealloc_buf + async->buf_write_ptr,
1676				   buf, n);
1677		if (m) {
1678			n -= m;
1679			retval = -EFAULT;
1680		}
1681		comedi_buf_write_free(async, n);
1682
1683		count += n;
1684		nbytes -= n;
1685
1686		buf += n;
1687		break;		/* makes device work like a pipe */
1688	}
1689	set_current_state(TASK_RUNNING);
1690	remove_wait_queue(&async->wait_head, &wait);
1691
1692done:
1693	return count ? count : retval;
1694}
1695
1696static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
1697				loff_t *offset)
1698{
1699	struct comedi_subdevice *s;
1700	struct comedi_async *async;
1701	int n, m, count = 0, retval = 0;
1702	DECLARE_WAITQUEUE(wait, current);
1703	const unsigned minor = iminor(file->f_dentry->d_inode);
1704	struct comedi_device_file_info *dev_file_info;
1705	struct comedi_device *dev;
1706	dev_file_info = comedi_get_device_file_info(minor);
1707
1708	if (dev_file_info == NULL)
1709	        return -ENODEV;
1710	dev = dev_file_info->device;
1711	if (dev == NULL)
1712	        return -ENODEV;
1713
1714	if (!dev->attached) {
1715		DPRINTK("no driver configured on comedi%i\n", dev->minor);
1716		retval = -ENODEV;
1717		goto done;
1718	}
1719
1720	s = comedi_get_read_subdevice(dev_file_info);
1721	if (s == NULL) {
1722		retval = -EIO;
1723		goto done;
1724	}
1725	async = s->async;
1726	if (!nbytes) {
1727		retval = 0;
1728		goto done;
1729	}
1730	if (!s->busy) {
1731		retval = 0;
1732		goto done;
1733	}
1734	if (s->busy != file) {
1735		retval = -EACCES;
1736		goto done;
1737	}
1738
1739	add_wait_queue(&async->wait_head, &wait);
1740	while (nbytes > 0 && !retval) {
1741		set_current_state(TASK_INTERRUPTIBLE);
1742
1743		n = nbytes;
1744
1745		m = comedi_buf_read_n_available(async);
1746		/* printk("%d available\n",m); */
1747		if (async->buf_read_ptr + m > async->prealloc_bufsz)
1748			m = async->prealloc_bufsz - async->buf_read_ptr;
1749		/* printk("%d contiguous\n",m); */
1750		if (m < n)
1751			n = m;
1752
1753		if (n == 0) {
1754			if (!(comedi_get_subdevice_runflags(s) & SRF_RUNNING)) {
1755				do_become_nonbusy(dev, s);
1756				if (comedi_get_subdevice_runflags(s) &
1757				    SRF_ERROR) {
1758					retval = -EPIPE;
1759				} else {
1760					retval = 0;
1761				}
1762				break;
1763			}
1764			if (file->f_flags & O_NONBLOCK) {
1765				retval = -EAGAIN;
1766				break;
1767			}
1768			if (signal_pending(current)) {
1769				retval = -ERESTARTSYS;
1770				break;
1771			}
1772			schedule();
1773			if (!s->busy) {
1774				retval = 0;
1775				break;
1776			}
1777			if (s->busy != file) {
1778				retval = -EACCES;
1779				break;
1780			}
1781			continue;
1782		}
1783		m = copy_to_user(buf, async->prealloc_buf +
1784				 async->buf_read_ptr, n);
1785		if (m) {
1786			n -= m;
1787			retval = -EFAULT;
1788		}
1789
1790		comedi_buf_read_alloc(async, n);
1791		comedi_buf_read_free(async, n);
1792
1793		count += n;
1794		nbytes -= n;
1795
1796		buf += n;
1797		break;		/* makes device work like a pipe */
1798	}
1799	if (!(comedi_get_subdevice_runflags(s) & (SRF_ERROR | SRF_RUNNING)) &&
1800	    async->buf_read_count - async->buf_write_count == 0) {
1801		do_become_nonbusy(dev, s);
1802	}
1803	set_current_state(TASK_RUNNING);
1804	remove_wait_queue(&async->wait_head, &wait);
1805
1806done:
1807	return count ? count : retval;
1808}
1809
1810/*
1811   This function restores a subdevice to an idle state.
1812 */
1813void do_become_nonbusy(struct comedi_device *dev, struct comedi_subdevice *s)
1814{
1815	struct comedi_async *async = s->async;
1816
1817	comedi_set_subdevice_runflags(s, SRF_RUNNING, 0);
1818	if (async) {
1819		comedi_reset_async_buf(async);
1820		async->inttrig = NULL;
1821	} else {
1822		printk(KERN_ERR
1823		       "BUG: (?) do_become_nonbusy called with async=0\n");
1824	}
1825
1826	s->busy = NULL;
1827}
1828
1829static int comedi_open(struct inode *inode, struct file *file)
1830{
1831	const unsigned minor = iminor(inode);
1832	struct comedi_device_file_info *dev_file_info =
1833	    comedi_get_device_file_info(minor);
1834	struct comedi_device *dev =
1835	    dev_file_info ? dev_file_info->device : NULL;
1836
1837	if (dev == NULL) {
1838		DPRINTK("invalid minor number\n");
1839		return -ENODEV;
1840	}
1841
1842	/* This is slightly hacky, but we want module autoloading
1843	 * to work for root.
1844	 * case: user opens device, attached -> ok
1845	 * case: user opens device, unattached, in_request_module=0 -> autoload
1846	 * case: user opens device, unattached, in_request_module=1 -> fail
1847	 * case: root opens device, attached -> ok
1848	 * case: root opens device, unattached, in_request_module=1 -> ok
1849	 *   (typically called from modprobe)
1850	 * case: root opens device, unattached, in_request_module=0 -> autoload
1851	 *
1852	 * The last could be changed to "-> ok", which would deny root
1853	 * autoloading.
1854	 */
1855	mutex_lock(&dev->mutex);
1856	if (dev->attached)
1857		goto ok;
1858	if (!capable(CAP_NET_ADMIN) && dev->in_request_module) {
1859		DPRINTK("in request module\n");
1860		mutex_unlock(&dev->mutex);
1861		return -ENODEV;
1862	}
1863	if (capable(CAP_NET_ADMIN) && dev->in_request_module)
1864		goto ok;
1865
1866	dev->in_request_module = 1;
1867
1868#ifdef CONFIG_KMOD
1869	mutex_unlock(&dev->mutex);
1870	request_module("char-major-%i-%i", COMEDI_MAJOR, dev->minor);
1871	mutex_lock(&dev->mutex);
1872#endif
1873
1874	dev->in_request_module = 0;
1875
1876	if (!dev->attached && !capable(CAP_NET_ADMIN)) {
1877		DPRINTK("not attached and not CAP_NET_ADMIN\n");
1878		mutex_unlock(&dev->mutex);
1879		return -ENODEV;
1880	}
1881ok:
1882	__module_get(THIS_MODULE);
1883
1884	if (dev->attached) {
1885		if (!try_module_get(dev->driver->module)) {
1886			module_put(THIS_MODULE);
1887			mutex_unlock(&dev->mutex);
1888			return -ENOSYS;
1889		}
1890	}
1891
1892	if (dev->attached && dev->use_count == 0 && dev->open) {
1893		int rc = dev->open(dev);
1894		if (rc < 0) {
1895			module_put(dev->driver->module);
1896			module_put(THIS_MODULE);
1897			mutex_unlock(&dev->mutex);
1898			return rc;
1899		}
1900	}
1901
1902	dev->use_count++;
1903
1904	mutex_unlock(&dev->mutex);
1905
1906	return 0;
1907}
1908
1909static int comedi_close(struct inode *inode, struct file *file)
1910{
1911	const unsigned minor = iminor(inode);
1912	struct comedi_subdevice *s = NULL;
1913	int i;
1914	struct comedi_device_file_info *dev_file_info;
1915	struct comedi_device *dev;
1916	dev_file_info = comedi_get_device_file_info(minor);
1917
1918	if (dev_file_info == NULL)
1919	        return -ENODEV;
1920	dev = dev_file_info->device;
1921	if (dev == NULL)
1922	        return -ENODEV;
1923
1924	mutex_lock(&dev->mutex);
1925
1926	if (dev->subdevices) {
1927		for (i = 0; i < dev->n_subdevices; i++) {
1928			s = dev->subdevices + i;
1929
1930			if (s->busy == file)
1931				do_cancel(dev, s);
1932			if (s->lock == file)
1933				s->lock = NULL;
1934		}
1935	}
1936	if (dev->attached && dev->use_count == 1 && dev->close)
1937		dev->close(dev);
1938
1939	module_put(THIS_MODULE);
1940	if (dev->attached)
1941		module_put(dev->driver->module);
1942
1943	dev->use_count--;
1944
1945	mutex_unlock(&dev->mutex);
1946
1947	if (file->f_flags & FASYNC)
1948		comedi_fasync(-1, file, 0);
1949
1950	return 0;
1951}
1952
1953static int comedi_fasync(int fd, struct file *file, int on)
1954{
1955	const unsigned minor = iminor(file->f_dentry->d_inode);
1956	struct comedi_device_file_info *dev_file_info;
1957	struct comedi_device *dev;
1958	dev_file_info = comedi_get_device_file_info(minor);
1959
1960	if (dev_file_info == NULL)
1961	        return -ENODEV;
1962	dev = dev_file_info->device;
1963	if (dev == NULL)
1964	        return -ENODEV;
1965
1966	return fasync_helper(fd, file, on, &dev->async_queue);
1967}
1968
1969const struct file_operations comedi_fops = {
1970	.owner = THIS_MODULE,
1971	.unlocked_ioctl = comedi_unlocked_ioctl,
1972	.compat_ioctl = comedi_compat_ioctl,
1973	.open = comedi_open,
1974	.release = comedi_close,
1975	.read = comedi_read,
1976	.write = comedi_write,
1977	.mmap = comedi_mmap,
1978	.poll = comedi_poll,
1979	.fasync = comedi_fasync,
1980	.llseek = noop_llseek,
1981};
1982
1983struct class *comedi_class;
1984static struct cdev comedi_cdev;
1985
1986static void comedi_cleanup_legacy_minors(void)
1987{
1988	unsigned i;
1989
1990	for (i = 0; i < comedi_num_legacy_minors; i++)
1991		comedi_free_board_minor(i);
1992}
1993
1994static int __init comedi_init(void)
1995{
1996	int i;
1997	int retval;
1998
1999	printk(KERN_INFO "comedi: version " COMEDI_RELEASE
2000	       " - http://www.comedi.org\n");
2001
2002	if (comedi_num_legacy_minors < 0 ||
2003	    comedi_num_legacy_minors > COMEDI_NUM_BOARD_MINORS) {
2004		printk(KERN_ERR "comedi: error: invalid value for module "
2005		       "parameter \"comedi_num_legacy_minors\".  Valid values "
2006		       "are 0 through %i.\n", COMEDI_NUM_BOARD_MINORS);
2007		return -EINVAL;
2008	}
2009
2010	/*
2011	 * comedi is unusable if both comedi_autoconfig and
2012	 * comedi_num_legacy_minors are zero, so we might as well adjust the
2013	 * defaults in that case
2014	 */
2015	if (comedi_autoconfig == 0 && comedi_num_legacy_minors == 0)
2016		comedi_num_legacy_minors = 16;
2017
2018	memset(comedi_file_info_table, 0,
2019	       sizeof(struct comedi_device_file_info *) * COMEDI_NUM_MINORS);
2020
2021	retval = register_chrdev_region(MKDEV(COMEDI_MAJOR, 0),
2022					COMEDI_NUM_MINORS, "comedi");
2023	if (retval)
2024		return -EIO;
2025	cdev_init(&comedi_cdev, &comedi_fops);
2026	comedi_cdev.owner = THIS_MODULE;
2027	kobject_set_name(&comedi_cdev.kobj, "comedi");
2028	if (cdev_add(&comedi_cdev, MKDEV(COMEDI_MAJOR, 0), COMEDI_NUM_MINORS)) {
2029		unregister_chrdev_region(MKDEV(COMEDI_MAJOR, 0),
2030					 COMEDI_NUM_MINORS);
2031		return -EIO;
2032	}
2033	comedi_class = class_create(THIS_MODULE, "comedi");
2034	if (IS_ERR(comedi_class)) {
2035		printk(KERN_ERR "comedi: failed to create class");
2036		cdev_del(&comedi_cdev);
2037		unregister_chrdev_region(MKDEV(COMEDI_MAJOR, 0),
2038					 COMEDI_NUM_MINORS);
2039		return PTR_ERR(comedi_class);
2040	}
2041
2042	/* XXX requires /proc interface */
2043	comedi_proc_init();
2044
2045	/* create devices files for legacy/manual use */
2046	for (i = 0; i < comedi_num_legacy_minors; i++) {
2047		int minor;
2048		minor = comedi_alloc_board_minor(NULL);
2049		if (minor < 0) {
2050			comedi_cleanup_legacy_minors();
2051			cdev_del(&comedi_cdev);
2052			unregister_chrdev_region(MKDEV(COMEDI_MAJOR, 0),
2053						 COMEDI_NUM_MINORS);
2054			return minor;
2055		}
2056	}
2057
2058	return 0;
2059}
2060
2061static void __exit comedi_cleanup(void)
2062{
2063	int i;
2064
2065	comedi_cleanup_legacy_minors();
2066	for (i = 0; i < COMEDI_NUM_MINORS; ++i)
2067		BUG_ON(comedi_file_info_table[i]);
2068
2069	class_destroy(comedi_class);
2070	cdev_del(&comedi_cdev);
2071	unregister_chrdev_region(MKDEV(COMEDI_MAJOR, 0), COMEDI_NUM_MINORS);
2072
2073	comedi_proc_cleanup();
2074}
2075
2076module_init(comedi_init);
2077module_exit(comedi_cleanup);
2078
2079void comedi_error(const struct comedi_device *dev, const char *s)
2080{
2081	printk(KERN_ERR "comedi%d: %s: %s\n", dev->minor,
2082	       dev->driver->driver_name, s);
2083}
2084EXPORT_SYMBOL(comedi_error);
2085
2086void comedi_event(struct comedi_device *dev, struct comedi_subdevice *s)
2087{
2088	struct comedi_async *async = s->async;
2089	unsigned runflags = 0;
2090	unsigned runflags_mask = 0;
2091
2092	/* DPRINTK("comedi_event 0x%x\n",mask); */
2093
2094	if ((comedi_get_subdevice_runflags(s) & SRF_RUNNING) == 0)
2095		return;
2096
2097	if (s->
2098	    async->events & (COMEDI_CB_EOA | COMEDI_CB_ERROR |
2099			     COMEDI_CB_OVERFLOW)) {
2100		runflags_mask |= SRF_RUNNING;
2101	}
2102	/* remember if an error event has occurred, so an error
2103	 * can be returned the next time the user does a read() */
2104	if (s->async->events & (COMEDI_CB_ERROR | COMEDI_CB_OVERFLOW)) {
2105		runflags_mask |= SRF_ERROR;
2106		runflags |= SRF_ERROR;
2107	}
2108	if (runflags_mask) {
2109		/*sets SRF_ERROR and SRF_RUNNING together atomically */
2110		comedi_set_subdevice_runflags(s, runflags_mask, runflags);
2111	}
2112
2113	if (async->cb_mask & s->async->events) {
2114		if (comedi_get_subdevice_runflags(s) & SRF_USER) {
2115			wake_up_interruptible(&async->wait_head);
2116			if (s->subdev_flags & SDF_CMD_READ)
2117				kill_fasync(&dev->async_queue, SIGIO, POLL_IN);
2118			if (s->subdev_flags & SDF_CMD_WRITE)
2119				kill_fasync(&dev->async_queue, SIGIO, POLL_OUT);
2120		} else {
2121			if (async->cb_func)
2122				async->cb_func(s->async->events, async->cb_arg);
2123		}
2124	}
2125	s->async->events = 0;
2126}
2127EXPORT_SYMBOL(comedi_event);
2128
2129unsigned comedi_get_subdevice_runflags(struct comedi_subdevice *s)
2130{
2131	unsigned long flags;
2132	unsigned runflags;
2133
2134	spin_lock_irqsave(&s->spin_lock, flags);
2135	runflags = s->runflags;
2136	spin_unlock_irqrestore(&s->spin_lock, flags);
2137	return runflags;
2138}
2139EXPORT_SYMBOL(comedi_get_subdevice_runflags);
2140
2141static int is_device_busy(struct comedi_device *dev)
2142{
2143	struct comedi_subdevice *s;
2144	int i;
2145
2146	if (!dev->attached)
2147		return 0;
2148
2149	for (i = 0; i < dev->n_subdevices; i++) {
2150		s = dev->subdevices + i;
2151		if (s->busy)
2152			return 1;
2153		if (s->async && s->async->mmap_count)
2154			return 1;
2155	}
2156
2157	return 0;
2158}
2159
2160static void comedi_device_init(struct comedi_device *dev)
2161{
2162	memset(dev, 0, sizeof(struct comedi_device));
2163	spin_lock_init(&dev->spinlock);
2164	mutex_init(&dev->mutex);
2165	dev->minor = -1;
2166}
2167
2168static void comedi_device_cleanup(struct comedi_device *dev)
2169{
2170	if (dev == NULL)
2171		return;
2172	mutex_lock(&dev->mutex);
2173	comedi_device_detach(dev);
2174	mutex_unlock(&dev->mutex);
2175	mutex_destroy(&dev->mutex);
2176}
2177
2178int comedi_alloc_board_minor(struct device *hardware_device)
2179{
2180	unsigned long flags;
2181	struct comedi_device_file_info *info;
2182	struct device *csdev;
2183	unsigned i;
2184	int retval;
2185
2186	info = kzalloc(sizeof(struct comedi_device_file_info), GFP_KERNEL);
2187	if (info == NULL)
2188		return -ENOMEM;
2189	info->device = kzalloc(sizeof(struct comedi_device), GFP_KERNEL);
2190	if (info->device == NULL) {
2191		kfree(info);
2192		return -ENOMEM;
2193	}
2194	comedi_device_init(info->device);
2195	spin_lock_irqsave(&comedi_file_info_table_lock, flags);
2196	for (i = 0; i < COMEDI_NUM_BOARD_MINORS; ++i) {
2197		if (comedi_file_info_table[i] == NULL) {
2198			comedi_file_info_table[i] = info;
2199			break;
2200		}
2201	}
2202	spin_unlock_irqrestore(&comedi_file_info_table_lock, flags);
2203	if (i == COMEDI_NUM_BOARD_MINORS) {
2204		comedi_device_cleanup(info->device);
2205		kfree(info->device);
2206		kfree(info);
2207		printk(KERN_ERR
2208		       "comedi: error: "
2209		       "ran out of minor numbers for board device files.\n");
2210		return -EBUSY;
2211	}
2212	info->device->minor = i;
2213	csdev = device_create(comedi_class, hardware_device,
2214			      MKDEV(COMEDI_MAJOR, i), NULL, "comedi%i", i);
2215	if (!IS_ERR(csdev))
2216		info->device->class_dev = csdev;
2217	dev_set_drvdata(csdev, info);
2218	retval = device_create_file(csdev, &dev_attr_max_read_buffer_kb);
2219	if (retval) {
2220		printk(KERN_ERR
2221		       "comedi: "
2222		       "failed to create sysfs attribute file \"%s\".\n",
2223		       dev_attr_max_read_buffer_kb.attr.name);
2224		comedi_free_board_minor(i);
2225		return retval;
2226	}
2227	retval = device_create_file(csdev, &dev_attr_read_buffer_kb);
2228	if (retval) {
2229		printk(KERN_ERR
2230		       "comedi: "
2231		       "failed to create sysfs attribute file \"%s\".\n",
2232		       dev_attr_read_buffer_kb.attr.name);
2233		comedi_free_board_minor(i);
2234		return retval;
2235	}
2236	retval = device_create_file(csdev, &dev_attr_max_write_buffer_kb);
2237	if (retval) {
2238		printk(KERN_ERR
2239		       "comedi: "
2240		       "failed to create sysfs attribute file \"%s\".\n",
2241		       dev_attr_max_write_buffer_kb.attr.name);
2242		comedi_free_board_minor(i);
2243		return retval;
2244	}
2245	retval = device_create_file(csdev, &dev_attr_write_buffer_kb);
2246	if (retval) {
2247		printk(KERN_ERR
2248		       "comedi: "
2249		       "failed to create sysfs attribute file \"%s\".\n",
2250		       dev_attr_write_buffer_kb.attr.name);
2251		comedi_free_board_minor(i);
2252		return retval;
2253	}
2254	return i;
2255}
2256
2257void comedi_free_board_minor(unsigned minor)
2258{
2259	unsigned long flags;
2260	struct comedi_device_file_info *info;
2261
2262	BUG_ON(minor >= COMEDI_NUM_BOARD_MINORS);
2263	spin_lock_irqsave(&comedi_file_info_table_lock, flags);
2264	info = comedi_file_info_table[minor];
2265	comedi_file_info_table[minor] = NULL;
2266	spin_unlock_irqrestore(&comedi_file_info_table_lock, flags);
2267
2268	if (info) {
2269		struct comedi_device *dev = info->device;
2270		if (dev) {
2271			if (dev->class_dev) {
2272				device_destroy(comedi_class,
2273					       MKDEV(COMEDI_MAJOR, dev->minor));
2274			}
2275			comedi_device_cleanup(dev);
2276			kfree(dev);
2277		}
2278		kfree(info);
2279	}
2280}
2281
2282int comedi_alloc_subdevice_minor(struct comedi_device *dev,
2283				 struct comedi_subdevice *s)
2284{
2285	unsigned long flags;
2286	struct comedi_device_file_info *info;
2287	struct device *csdev;
2288	unsigned i;
2289	int retval;
2290
2291	info = kmalloc(sizeof(struct comedi_device_file_info), GFP_KERNEL);
2292	if (info == NULL)
2293		return -ENOMEM;
2294	info->device = dev;
2295	info->read_subdevice = s;
2296	info->write_subdevice = s;
2297	spin_lock_irqsave(&comedi_file_info_table_lock, flags);
2298	for (i = COMEDI_FIRST_SUBDEVICE_MINOR; i < COMEDI_NUM_MINORS; ++i) {
2299		if (comedi_file_info_table[i] == NULL) {
2300			comedi_file_info_table[i] = info;
2301			break;
2302		}
2303	}
2304	spin_unlock_irqrestore(&comedi_file_info_table_lock, flags);
2305	if (i == COMEDI_NUM_MINORS) {
2306		kfree(info);
2307		printk(KERN_ERR
2308		       "comedi: error: "
2309		       "ran out of minor numbers for board device files.\n");
2310		return -EBUSY;
2311	}
2312	s->minor = i;
2313	csdev = device_create(comedi_class, dev->class_dev,
2314			      MKDEV(COMEDI_MAJOR, i), NULL, "comedi%i_subd%i",
2315			      dev->minor, (int)(s - dev->subdevices));
2316	if (!IS_ERR(csdev))
2317		s->class_dev = csdev;
2318	dev_set_drvdata(csdev, info);
2319	retval = device_create_file(csdev, &dev_attr_max_read_buffer_kb);
2320	if (retval) {
2321		printk(KERN_ERR
2322		       "comedi: "
2323		       "failed to create sysfs attribute file \"%s\".\n",
2324		       dev_attr_max_read_buffer_kb.attr.name);
2325		comedi_free_subdevice_minor(s);
2326		return retval;
2327	}
2328	retval = device_create_file(csdev, &dev_attr_read_buffer_kb);
2329	if (retval) {
2330		printk(KERN_ERR
2331		       "comedi: "
2332		       "failed to create sysfs attribute file \"%s\".\n",
2333		       dev_attr_read_buffer_kb.attr.name);
2334		comedi_free_subdevice_minor(s);
2335		return retval;
2336	}
2337	retval = device_create_file(csdev, &dev_attr_max_write_buffer_kb);
2338	if (retval) {
2339		printk(KERN_ERR
2340		       "comedi: "
2341		       "failed to create sysfs attribute file \"%s\".\n",
2342		       dev_attr_max_write_buffer_kb.attr.name);
2343		comedi_free_subdevice_minor(s);
2344		return retval;
2345	}
2346	retval = device_create_file(csdev, &dev_attr_write_buffer_kb);
2347	if (retval) {
2348		printk(KERN_ERR
2349		       "comedi: "
2350		       "failed to create sysfs attribute file \"%s\".\n",
2351		       dev_attr_write_buffer_kb.attr.name);
2352		comedi_free_subdevice_minor(s);
2353		return retval;
2354	}
2355	return i;
2356}
2357
2358void comedi_free_subdevice_minor(struct comedi_subdevice *s)
2359{
2360	unsigned long flags;
2361	struct comedi_device_file_info *info;
2362
2363	if (s == NULL)
2364		return;
2365	if (s->minor < 0)
2366		return;
2367
2368	BUG_ON(s->minor >= COMEDI_NUM_MINORS);
2369	BUG_ON(s->minor < COMEDI_FIRST_SUBDEVICE_MINOR);
2370
2371	spin_lock_irqsave(&comedi_file_info_table_lock, flags);
2372	info = comedi_file_info_table[s->minor];
2373	comedi_file_info_table[s->minor] = NULL;
2374	spin_unlock_irqrestore(&comedi_file_info_table_lock, flags);
2375
2376	if (s->class_dev) {
2377		device_destroy(comedi_class, MKDEV(COMEDI_MAJOR, s->minor));
2378		s->class_dev = NULL;
2379	}
2380	kfree(info);
2381}
2382
2383struct comedi_device_file_info *comedi_get_device_file_info(unsigned minor)
2384{
2385	unsigned long flags;
2386	struct comedi_device_file_info *info;
2387
2388	BUG_ON(minor >= COMEDI_NUM_MINORS);
2389	spin_lock_irqsave(&comedi_file_info_table_lock, flags);
2390	info = comedi_file_info_table[minor];
2391	spin_unlock_irqrestore(&comedi_file_info_table_lock, flags);
2392	return info;
2393}
2394EXPORT_SYMBOL_GPL(comedi_get_device_file_info);
2395
2396static int resize_async_buffer(struct comedi_device *dev,
2397			       struct comedi_subdevice *s,
2398			       struct comedi_async *async, unsigned new_size)
2399{
2400	int retval;
2401
2402	if (new_size > async->max_bufsize)
2403		return -EPERM;
2404
2405	if (s->busy) {
2406		DPRINTK("subdevice is busy, cannot resize buffer\n");
2407		return -EBUSY;
2408	}
2409	if (async->mmap_count) {
2410		DPRINTK("subdevice is mmapped, cannot resize buffer\n");
2411		return -EBUSY;
2412	}
2413
2414	if (!async->prealloc_buf)
2415		return -EINVAL;
2416
2417	/* make sure buffer is an integral number of pages
2418	 * (we round up) */
2419	new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
2420
2421	retval = comedi_buf_alloc(dev, s, new_size);
2422	if (retval < 0)
2423		return retval;
2424
2425	if (s->buf_change) {
2426		retval = s->buf_change(dev, s, new_size);
2427		if (retval < 0)
2428			return retval;
2429	}
2430
2431	DPRINTK("comedi%i subd %d buffer resized to %i bytes\n",
2432		dev->minor, (int)(s - dev->subdevices), async->prealloc_bufsz);
2433	return 0;
2434}
2435
2436/* sysfs attribute files */
2437
2438static const unsigned bytes_per_kibi = 1024;
2439
2440static ssize_t show_max_read_buffer_kb(struct device *dev,
2441				       struct device_attribute *attr, char *buf)
2442{
2443	ssize_t retval;
2444	struct comedi_device_file_info *info = dev_get_drvdata(dev);
2445	unsigned max_buffer_size_kb = 0;
2446	struct comedi_subdevice *const read_subdevice =
2447	    comedi_get_read_subdevice(info);
2448
2449	mutex_lock(&info->device->mutex);
2450	if (read_subdevice &&
2451	    (read_subdevice->subdev_flags & SDF_CMD_READ) &&
2452	    read_subdevice->async) {
2453		max_buffer_size_kb = read_subdevice->async->max_bufsize /
2454		    bytes_per_kibi;
2455	}
2456	retval = snprintf(buf, PAGE_SIZE, "%i\n", max_buffer_size_kb);
2457	mutex_unlock(&info->device->mutex);
2458
2459	return retval;
2460}
2461
2462static ssize_t store_max_read_buffer_kb(struct device *dev,
2463					struct device_attribute *attr,
2464					const char *buf, size_t count)
2465{
2466	struct comedi_device_file_info *info = dev_get_drvdata(dev);
2467	unsigned long new_max_size_kb;
2468	uint64_t new_max_size;
2469	struct comedi_subdevice *const read_subdevice =
2470	    comedi_get_read_subdevice(info);
2471
2472	if (strict_strtoul(buf, 10, &new_max_size_kb))
2473		return -EINVAL;
2474	if (new_max_size_kb != (uint32_t) new_max_size_kb)
2475		return -EINVAL;
2476	new_max_size = ((uint64_t) new_max_size_kb) * bytes_per_kibi;
2477	if (new_max_size != (uint32_t) new_max_size)
2478		return -EINVAL;
2479
2480	mutex_lock(&info->device->mutex);
2481	if (read_subdevice == NULL ||
2482	    (read_subdevice->subdev_flags & SDF_CMD_READ) == 0 ||
2483	    read_subdevice->async == NULL) {
2484		mutex_unlock(&info->device->mutex);
2485		return -EINVAL;
2486	}
2487	read_subdevice->async->max_bufsize = new_max_size;
2488	mutex_unlock(&info->device->mutex);
2489
2490	return count;
2491}
2492
2493static struct device_attribute dev_attr_max_read_buffer_kb = {
2494	.attr = {
2495		 .name = "max_read_buffer_kb",
2496		 .mode = S_IRUGO | S_IWUSR},
2497	.show = &show_max_read_buffer_kb,
2498	.store = &store_max_read_buffer_kb
2499};
2500
2501static ssize_t show_read_buffer_kb(struct device *dev,
2502				   struct device_attribute *attr, char *buf)
2503{
2504	ssize_t retval;
2505	struct comedi_device_file_info *info = dev_get_drvdata(dev);
2506	unsigned buffer_size_kb = 0;
2507	struct comedi_subdevice *const read_subdevice =
2508	    comedi_get_read_subdevice(info);
2509
2510	mutex_lock(&info->device->mutex);
2511	if (read_subdevice &&
2512	    (read_subdevice->subdev_flags & SDF_CMD_READ) &&
2513	    read_subdevice->async) {
2514		buffer_size_kb = read_subdevice->async->prealloc_bufsz /
2515		    bytes_per_kibi;
2516	}
2517	retval = snprintf(buf, PAGE_SIZE, "%i\n", buffer_size_kb);
2518	mutex_unlock(&info->device->mutex);
2519
2520	return retval;
2521}
2522
2523static ssize_t store_read_buffer_kb(struct device *dev,
2524				    struct device_attribute *attr,
2525				    const char *buf, size_t count)
2526{
2527	struct comedi_device_file_info *info = dev_get_drvdata(dev);
2528	unsigned long new_size_kb;
2529	uint64_t new_size;
2530	int retval;
2531	struct comedi_subdevice *const read_subdevice =
2532	    comedi_get_read_subdevice(info);
2533
2534	if (strict_strtoul(buf, 10, &new_size_kb))
2535		return -EINVAL;
2536	if (new_size_kb != (uint32_t) new_size_kb)
2537		return -EINVAL;
2538	new_size = ((uint64_t) new_size_kb) * bytes_per_kibi;
2539	if (new_size != (uint32_t) new_size)
2540		return -EINVAL;
2541
2542	mutex_lock(&info->device->mutex);
2543	if (read_subdevice == NULL ||
2544	    (read_subdevice->subdev_flags & SDF_CMD_READ) == 0 ||
2545	    read_subdevice->async == NULL) {
2546		mutex_unlock(&info->device->mutex);
2547		return -EINVAL;
2548	}
2549	retval = resize_async_buffer(info->device, read_subdevice,
2550				     read_subdevice->async, new_size);
2551	mutex_unlock(&info->device->mutex);
2552
2553	if (retval < 0)
2554		return retval;
2555	return count;
2556}
2557
2558static struct device_attribute dev_attr_read_buffer_kb = {
2559	.attr = {
2560		 .name = "read_buffer_kb",
2561		 .mode = S_IRUGO | S_IWUSR | S_IWGRP},
2562	.show = &show_read_buffer_kb,
2563	.store = &store_read_buffer_kb
2564};
2565
2566static ssize_t show_max_write_buffer_kb(struct device *dev,
2567					struct device_attribute *attr,
2568					char *buf)
2569{
2570	ssize_t retval;
2571	struct comedi_device_file_info *info = dev_get_drvdata(dev);
2572	unsigned max_buffer_size_kb = 0;
2573	struct comedi_subdevice *const write_subdevice =
2574	    comedi_get_write_subdevice(info);
2575
2576	mutex_lock(&info->device->mutex);
2577	if (write_subdevice &&
2578	    (write_subdevice->subdev_flags & SDF_CMD_WRITE) &&
2579	    write_subdevice->async) {
2580		max_buffer_size_kb = write_subdevice->async->max_bufsize /
2581		    bytes_per_kibi;
2582	}
2583	retval = snprintf(buf, PAGE_SIZE, "%i\n", max_buffer_size_kb);
2584	mutex_unlock(&info->device->mutex);
2585
2586	return retval;
2587}
2588
2589static ssize_t store_max_write_buffer_kb(struct device *dev,
2590					 struct device_attribute *attr,
2591					 const char *buf, size_t count)
2592{
2593	struct comedi_device_file_info *info = dev_get_drvdata(dev);
2594	unsigned long new_max_size_kb;
2595	uint64_t new_max_size;
2596	struct comedi_subdevice *const write_subdevice =
2597	    comedi_get_write_subdevice(info);
2598
2599	if (strict_strtoul(buf, 10, &new_max_size_kb))
2600		return -EINVAL;
2601	if (new_max_size_kb != (uint32_t) new_max_size_kb)
2602		return -EINVAL;
2603	new_max_size = ((uint64_t) new_max_size_kb) * bytes_per_kibi;
2604	if (new_max_size != (uint32_t) new_max_size)
2605		return -EINVAL;
2606
2607	mutex_lock(&info->device->mutex);
2608	if (write_subdevice == NULL ||
2609	    (write_subdevice->subdev_flags & SDF_CMD_WRITE) == 0 ||
2610	    write_subdevice->async == NULL) {
2611		mutex_unlock(&info->device->mutex);
2612		return -EINVAL;
2613	}
2614	write_subdevice->async->max_bufsize = new_max_size;
2615	mutex_unlock(&info->device->mutex);
2616
2617	return count;
2618}
2619
2620static struct device_attribute dev_attr_max_write_buffer_kb = {
2621	.attr = {
2622		 .name = "max_write_buffer_kb",
2623		 .mode = S_IRUGO | S_IWUSR},
2624	.show = &show_max_write_buffer_kb,
2625	.store = &store_max_write_buffer_kb
2626};
2627
2628static ssize_t show_write_buffer_kb(struct device *dev,
2629				    struct device_attribute *attr, char *buf)
2630{
2631	ssize_t retval;
2632	struct comedi_device_file_info *info = dev_get_drvdata(dev);
2633	unsigned buffer_size_kb = 0;
2634	struct comedi_subdevice *const write_subdevice =
2635	    comedi_get_write_subdevice(info);
2636
2637	mutex_lock(&info->device->mutex);
2638	if (write_subdevice &&
2639	    (write_subdevice->subdev_flags & SDF_CMD_WRITE) &&
2640	    write_subdevice->async) {
2641		buffer_size_kb = write_subdevice->async->prealloc_bufsz /
2642		    bytes_per_kibi;
2643	}
2644	retval = snprintf(buf, PAGE_SIZE, "%i\n", buffer_size_kb);
2645	mutex_unlock(&info->device->mutex);
2646
2647	return retval;
2648}
2649
2650static ssize_t store_write_buffer_kb(struct device *dev,
2651				     struct device_attribute *attr,
2652				     const char *buf, size_t count)
2653{
2654	struct comedi_device_file_info *info = dev_get_drvdata(dev);
2655	unsigned long new_size_kb;
2656	uint64_t new_size;
2657	int retval;
2658	struct comedi_subdevice *const write_subdevice =
2659	    comedi_get_write_subdevice(info);
2660
2661	if (strict_strtoul(buf, 10, &new_size_kb))
2662		return -EINVAL;
2663	if (new_size_kb != (uint32_t) new_size_kb)
2664		return -EINVAL;
2665	new_size = ((uint64_t) new_size_kb) * bytes_per_kibi;
2666	if (new_size != (uint32_t) new_size)
2667		return -EINVAL;
2668
2669	mutex_lock(&info->device->mutex);
2670	if (write_subdevice == NULL ||
2671	    (write_subdevice->subdev_flags & SDF_CMD_WRITE) == 0 ||
2672	    write_subdevice->async == NULL) {
2673		mutex_unlock(&info->device->mutex);
2674		return -EINVAL;
2675	}
2676	retval = resize_async_buffer(info->device, write_subdevice,
2677				     write_subdevice->async, new_size);
2678	mutex_unlock(&info->device->mutex);
2679
2680	if (retval < 0)
2681		return retval;
2682	return count;
2683}
2684
2685static struct device_attribute dev_attr_write_buffer_kb = {
2686	.attr = {
2687		 .name = "write_buffer_kb",
2688		 .mode = S_IRUGO | S_IWUSR | S_IWGRP},
2689	.show = &show_write_buffer_kb,
2690	.store = &store_write_buffer_kb
2691};
2692