xref: /linux/drivers/comedi/drivers.c (revision 0ea5c948cb64bab5bc7a5516774eb8536f05aa0d)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  module/drivers.c
4  *  functions for manipulating drivers
5  *
6  *  COMEDI - Linux Control and Measurement Device Interface
7  *  Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
8  *  Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net>
9  */
10 
11 #include <linux/device.h>
12 #include <linux/module.h>
13 #include <linux/errno.h>
14 #include <linux/kernel.h>
15 #include <linux/ioport.h>
16 #include <linux/slab.h>
17 #include <linux/dma-direction.h>
18 #include <linux/interrupt.h>
19 #include <linux/firmware.h>
20 #include <linux/comedi/comedidev.h>
21 #include "comedi_internal.h"
22 
23 struct comedi_driver *comedi_drivers;
24 /* protects access to comedi_drivers */
25 DEFINE_MUTEX(comedi_drivers_list_lock);
26 
27 /**
28  * comedi_set_hw_dev() - Set hardware device associated with COMEDI device
29  * @dev: COMEDI device.
30  * @hw_dev: Hardware device.
31  *
32  * For automatically configured COMEDI devices (resulting from a call to
33  * comedi_auto_config() or one of its wrappers from the low-level COMEDI
34  * driver), comedi_set_hw_dev() is called automatically by the COMEDI core
35  * to associate the COMEDI device with the hardware device.  It can also be
36  * called directly by "legacy" low-level COMEDI drivers that rely on the
37  * %COMEDI_DEVCONFIG ioctl to configure the hardware as long as the hardware
38  * has a &struct device.
39  *
40  * If @dev->hw_dev is NULL, it gets a reference to @hw_dev and sets
41  * @dev->hw_dev, otherwise, it does nothing.  Calling it multiple times
42  * with the same hardware device is not considered an error.  If it gets
43  * a reference to the hardware device, it will be automatically 'put' when
44  * the device is detached from COMEDI.
45  *
46  * Returns 0 if @dev->hw_dev was NULL or the same as @hw_dev, otherwise
47  * returns -EEXIST.
48  */
comedi_set_hw_dev(struct comedi_device * dev,struct device * hw_dev)49 int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev)
50 {
51 	if (hw_dev == dev->hw_dev)
52 		return 0;
53 	if (dev->hw_dev)
54 		return -EEXIST;
55 	dev->hw_dev = get_device(hw_dev);
56 	return 0;
57 }
58 EXPORT_SYMBOL_GPL(comedi_set_hw_dev);
59 
comedi_clear_hw_dev(struct comedi_device * dev)60 static void comedi_clear_hw_dev(struct comedi_device *dev)
61 {
62 	put_device(dev->hw_dev);
63 	dev->hw_dev = NULL;
64 }
65 
66 /**
67  * comedi_alloc_devpriv() - Allocate memory for the device private data
68  * @dev: COMEDI device.
69  * @size: Size of the memory to allocate.
70  *
71  * The allocated memory is zero-filled.  @dev->private points to it on
72  * return.  The memory will be automatically freed when the COMEDI device is
73  * "detached".
74  *
75  * Returns a pointer to the allocated memory, or NULL on failure.
76  */
comedi_alloc_devpriv(struct comedi_device * dev,size_t size)77 void *comedi_alloc_devpriv(struct comedi_device *dev, size_t size)
78 {
79 	dev->private = kzalloc(size, GFP_KERNEL);
80 	return dev->private;
81 }
82 EXPORT_SYMBOL_GPL(comedi_alloc_devpriv);
83 
84 /**
85  * comedi_alloc_subdevices() - Allocate subdevices for COMEDI device
86  * @dev: COMEDI device.
87  * @num_subdevices: Number of subdevices to allocate.
88  *
89  * Allocates and initializes an array of &struct comedi_subdevice for the
90  * COMEDI device.  If successful, sets @dev->subdevices to point to the
91  * first one and @dev->n_subdevices to the number.
92  *
93  * Returns 0 on success, -EINVAL if @num_subdevices is < 1, or -ENOMEM if
94  * failed to allocate the memory.
95  */
comedi_alloc_subdevices(struct comedi_device * dev,int num_subdevices)96 int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
97 {
98 	struct comedi_subdevice *s;
99 	int i;
100 
101 	if (num_subdevices < 1)
102 		return -EINVAL;
103 
104 	s = kcalloc(num_subdevices, sizeof(*s), GFP_KERNEL);
105 	if (!s)
106 		return -ENOMEM;
107 	dev->subdevices = s;
108 	dev->n_subdevices = num_subdevices;
109 
110 	for (i = 0; i < num_subdevices; ++i) {
111 		s = &dev->subdevices[i];
112 		s->device = dev;
113 		s->index = i;
114 		s->async_dma_dir = DMA_NONE;
115 		spin_lock_init(&s->spin_lock);
116 		s->minor = -1;
117 	}
118 	return 0;
119 }
120 EXPORT_SYMBOL_GPL(comedi_alloc_subdevices);
121 
122 /**
123  * comedi_alloc_subdev_readback() - Allocate memory for the subdevice readback
124  * @s: COMEDI subdevice.
125  *
126  * This is called by low-level COMEDI drivers to allocate an array to record
127  * the last values written to a subdevice's analog output channels (at least
128  * by the %INSN_WRITE instruction), to allow them to be read back by an
129  * %INSN_READ instruction.  It also provides a default handler for the
130  * %INSN_READ instruction unless one has already been set.
131  *
132  * On success, @s->readback points to the first element of the array, which
133  * is zero-filled.  The low-level driver is responsible for updating its
134  * contents.  @s->insn_read will be set to comedi_readback_insn_read()
135  * unless it is already non-NULL.
136  *
137  * Returns 0 on success, -EINVAL if the subdevice has no channels, or
138  * -ENOMEM on allocation failure.
139  */
comedi_alloc_subdev_readback(struct comedi_subdevice * s)140 int comedi_alloc_subdev_readback(struct comedi_subdevice *s)
141 {
142 	if (!s->n_chan)
143 		return -EINVAL;
144 
145 	s->readback = kcalloc(s->n_chan, sizeof(*s->readback), GFP_KERNEL);
146 	if (!s->readback)
147 		return -ENOMEM;
148 
149 	if (!s->insn_read)
150 		s->insn_read = comedi_readback_insn_read;
151 
152 	return 0;
153 }
154 EXPORT_SYMBOL_GPL(comedi_alloc_subdev_readback);
155 
comedi_device_detach_cleanup(struct comedi_device * dev)156 static void comedi_device_detach_cleanup(struct comedi_device *dev)
157 {
158 	int i;
159 	struct comedi_subdevice *s;
160 
161 	lockdep_assert_held(&dev->attach_lock);
162 	lockdep_assert_held(&dev->mutex);
163 	if (dev->subdevices) {
164 		for (i = 0; i < dev->n_subdevices; i++) {
165 			s = &dev->subdevices[i];
166 			if (comedi_can_auto_free_spriv(s))
167 				kfree(s->private);
168 			comedi_free_subdevice_minor(s);
169 			if (s->async) {
170 				comedi_buf_alloc(dev, s, 0);
171 				kfree(s->async);
172 			}
173 			kfree(s->readback);
174 		}
175 		kfree(dev->subdevices);
176 		dev->subdevices = NULL;
177 		dev->n_subdevices = 0;
178 	}
179 	kfree(dev->private);
180 	if (!IS_ERR(dev->pacer))
181 		kfree(dev->pacer);
182 	dev->private = NULL;
183 	dev->pacer = NULL;
184 	dev->driver = NULL;
185 	dev->board_name = NULL;
186 	dev->board_ptr = NULL;
187 	dev->mmio = NULL;
188 	dev->iobase = 0;
189 	dev->iolen = 0;
190 	dev->ioenabled = false;
191 	dev->irq = 0;
192 	dev->read_subdev = NULL;
193 	dev->write_subdev = NULL;
194 	dev->open = NULL;
195 	dev->close = NULL;
196 	comedi_clear_hw_dev(dev);
197 }
198 
comedi_device_detach(struct comedi_device * dev)199 void comedi_device_detach(struct comedi_device *dev)
200 {
201 	lockdep_assert_held(&dev->mutex);
202 	comedi_device_cancel_all(dev);
203 	down_write(&dev->attach_lock);
204 	dev->attached = false;
205 	dev->detach_count++;
206 	if (dev->driver)
207 		dev->driver->detach(dev);
208 	comedi_device_detach_cleanup(dev);
209 	up_write(&dev->attach_lock);
210 }
211 
poll_invalid(struct comedi_device * dev,struct comedi_subdevice * s)212 static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
213 {
214 	return -EINVAL;
215 }
216 
insn_device_inval(struct comedi_device * dev,struct comedi_insn * insn,unsigned int * data)217 static int insn_device_inval(struct comedi_device *dev,
218 			     struct comedi_insn *insn, unsigned int *data)
219 {
220 	return -EINVAL;
221 }
222 
get_zero_valid_routes(struct comedi_device * dev,unsigned int n_pairs,unsigned int * pair_data)223 static unsigned int get_zero_valid_routes(struct comedi_device *dev,
224 					  unsigned int n_pairs,
225 					  unsigned int *pair_data)
226 {
227 	return 0;
228 }
229 
insn_inval(struct comedi_device * dev,struct comedi_subdevice * s,struct comedi_insn * insn,unsigned int * data)230 int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
231 	       struct comedi_insn *insn, unsigned int *data)
232 {
233 	return -EINVAL;
234 }
235 
236 /**
237  * comedi_readback_insn_read() - A generic (*insn_read) for subdevice readback.
238  * @dev: COMEDI device.
239  * @s: COMEDI subdevice.
240  * @insn: COMEDI instruction.
241  * @data: Pointer to return the readback data.
242  *
243  * Handles the %INSN_READ instruction for subdevices that use the readback
244  * array allocated by comedi_alloc_subdev_readback().  It may be used
245  * directly as the subdevice's handler (@s->insn_read) or called via a
246  * wrapper.
247  *
248  * @insn->n is normally 1, which will read a single value.  If higher, the
249  * same element of the readback array will be read multiple times.
250  *
251  * Returns @insn->n on success, or -EINVAL if @s->readback is NULL.
252  */
comedi_readback_insn_read(struct comedi_device * dev,struct comedi_subdevice * s,struct comedi_insn * insn,unsigned int * data)253 int comedi_readback_insn_read(struct comedi_device *dev,
254 			      struct comedi_subdevice *s,
255 			      struct comedi_insn *insn,
256 			      unsigned int *data)
257 {
258 	unsigned int chan = CR_CHAN(insn->chanspec);
259 	int i;
260 
261 	if (!s->readback)
262 		return -EINVAL;
263 
264 	for (i = 0; i < insn->n; i++)
265 		data[i] = s->readback[chan];
266 
267 	return insn->n;
268 }
269 EXPORT_SYMBOL_GPL(comedi_readback_insn_read);
270 
271 /**
272  * comedi_timeout() - Busy-wait for a driver condition to occur
273  * @dev: COMEDI device.
274  * @s: COMEDI subdevice.
275  * @insn: COMEDI instruction.
276  * @cb: Callback to check for the condition.
277  * @context: Private context from the driver.
278  *
279  * Busy-waits for up to a second (%COMEDI_TIMEOUT_MS) for the condition or
280  * some error (other than -EBUSY) to occur.  The parameters @dev, @s, @insn,
281  * and @context are passed to the callback function, which returns -EBUSY to
282  * continue waiting or some other value to stop waiting (generally 0 if the
283  * condition occurred, or some error value).
284  *
285  * Returns -ETIMEDOUT if timed out, otherwise the return value from the
286  * callback function.
287  */
comedi_timeout(struct comedi_device * dev,struct comedi_subdevice * s,struct comedi_insn * insn,int (* cb)(struct comedi_device * dev,struct comedi_subdevice * s,struct comedi_insn * insn,unsigned long context),unsigned long context)288 int comedi_timeout(struct comedi_device *dev,
289 		   struct comedi_subdevice *s,
290 		   struct comedi_insn *insn,
291 		   int (*cb)(struct comedi_device *dev,
292 			     struct comedi_subdevice *s,
293 			     struct comedi_insn *insn,
294 			     unsigned long context),
295 		   unsigned long context)
296 {
297 	unsigned long timeout = jiffies + msecs_to_jiffies(COMEDI_TIMEOUT_MS);
298 	int ret;
299 
300 	while (time_before(jiffies, timeout)) {
301 		ret = cb(dev, s, insn, context);
302 		if (ret != -EBUSY)
303 			return ret;	/* success (0) or non EBUSY errno */
304 		cpu_relax();
305 	}
306 	return -ETIMEDOUT;
307 }
308 EXPORT_SYMBOL_GPL(comedi_timeout);
309 
310 /**
311  * comedi_dio_insn_config() - Boilerplate (*insn_config) for DIO subdevices
312  * @dev: COMEDI device.
313  * @s: COMEDI subdevice.
314  * @insn: COMEDI instruction.
315  * @data: Instruction parameters and return data.
316  * @mask: io_bits mask for grouped channels, or 0 for single channel.
317  *
318  * If @mask is 0, it is replaced with a single-bit mask corresponding to the
319  * channel number specified by @insn->chanspec.  Otherwise, @mask
320  * corresponds to a group of channels (which should include the specified
321  * channel) that are always configured together as inputs or outputs.
322  *
323  * Partially handles the %INSN_CONFIG_DIO_INPUT, %INSN_CONFIG_DIO_OUTPUTS,
324  * and %INSN_CONFIG_DIO_QUERY instructions.  The first two update
325  * @s->io_bits to record the directions of the masked channels.  The last
326  * one sets @data[1] to the current direction of the group of channels
327  * (%COMEDI_INPUT) or %COMEDI_OUTPUT) as recorded in @s->io_bits.
328  *
329  * The caller is responsible for updating the DIO direction in the hardware
330  * registers if this function returns 0.
331  *
332  * Returns 0 for a %INSN_CONFIG_DIO_INPUT or %INSN_CONFIG_DIO_OUTPUT
333  * instruction, @insn->n (> 0) for a %INSN_CONFIG_DIO_QUERY instruction, or
334  * -EINVAL for some other instruction.
335  */
comedi_dio_insn_config(struct comedi_device * dev,struct comedi_subdevice * s,struct comedi_insn * insn,unsigned int * data,unsigned int mask)336 int comedi_dio_insn_config(struct comedi_device *dev,
337 			   struct comedi_subdevice *s,
338 			   struct comedi_insn *insn,
339 			   unsigned int *data,
340 			   unsigned int mask)
341 {
342 	unsigned int chan_mask = 1 << CR_CHAN(insn->chanspec);
343 
344 	if (!mask)
345 		mask = chan_mask;
346 
347 	switch (data[0]) {
348 	case INSN_CONFIG_DIO_INPUT:
349 		s->io_bits &= ~mask;
350 		break;
351 
352 	case INSN_CONFIG_DIO_OUTPUT:
353 		s->io_bits |= mask;
354 		break;
355 
356 	case INSN_CONFIG_DIO_QUERY:
357 		data[1] = (s->io_bits & mask) ? COMEDI_OUTPUT : COMEDI_INPUT;
358 		return insn->n;
359 
360 	default:
361 		return -EINVAL;
362 	}
363 
364 	return 0;
365 }
366 EXPORT_SYMBOL_GPL(comedi_dio_insn_config);
367 
368 /**
369  * comedi_dio_update_state() - Update the internal state of DIO subdevices
370  * @s: COMEDI subdevice.
371  * @data: The channel mask and bits to update.
372  *
373  * Updates @s->state which holds the internal state of the outputs for DIO
374  * or DO subdevices (up to 32 channels).  @data[0] contains a bit-mask of
375  * the channels to be updated.  @data[1] contains a bit-mask of those
376  * channels to be set to '1'.  The caller is responsible for updating the
377  * outputs in hardware according to @s->state.  As a minimum, the channels
378  * in the returned bit-mask need to be updated.
379  *
380  * Returns @mask with non-existent channels removed.
381  */
comedi_dio_update_state(struct comedi_subdevice * s,unsigned int * data)382 unsigned int comedi_dio_update_state(struct comedi_subdevice *s,
383 				     unsigned int *data)
384 {
385 	unsigned int chanmask = (s->n_chan < 32) ? ((1 << s->n_chan) - 1)
386 						 : 0xffffffff;
387 	unsigned int mask = data[0] & chanmask;
388 	unsigned int bits = data[1];
389 
390 	if (mask) {
391 		s->state &= ~mask;
392 		s->state |= (bits & mask);
393 	}
394 
395 	return mask;
396 }
397 EXPORT_SYMBOL_GPL(comedi_dio_update_state);
398 
399 /**
400  * comedi_bytes_per_scan_cmd() - Get length of asynchronous command "scan" in
401  * bytes
402  * @s: COMEDI subdevice.
403  * @cmd: COMEDI command.
404  *
405  * Determines the overall scan length according to the subdevice type and the
406  * number of channels in the scan for the specified command.
407  *
408  * For digital input, output or input/output subdevices, samples for
409  * multiple channels are assumed to be packed into one or more unsigned
410  * short or unsigned int values according to the subdevice's %SDF_LSAMPL
411  * flag.  For other types of subdevice, samples are assumed to occupy a
412  * whole unsigned short or unsigned int according to the %SDF_LSAMPL flag.
413  *
414  * Returns the overall scan length in bytes.
415  */
comedi_bytes_per_scan_cmd(struct comedi_subdevice * s,struct comedi_cmd * cmd)416 unsigned int comedi_bytes_per_scan_cmd(struct comedi_subdevice *s,
417 				       struct comedi_cmd *cmd)
418 {
419 	unsigned int num_samples;
420 	unsigned int bits_per_sample;
421 
422 	switch (s->type) {
423 	case COMEDI_SUBD_DI:
424 	case COMEDI_SUBD_DO:
425 	case COMEDI_SUBD_DIO:
426 		bits_per_sample = 8 * comedi_bytes_per_sample(s);
427 		num_samples = DIV_ROUND_UP(cmd->scan_end_arg, bits_per_sample);
428 		break;
429 	default:
430 		num_samples = cmd->scan_end_arg;
431 		break;
432 	}
433 	return comedi_samples_to_bytes(s, num_samples);
434 }
435 EXPORT_SYMBOL_GPL(comedi_bytes_per_scan_cmd);
436 
437 /**
438  * comedi_bytes_per_scan() - Get length of asynchronous command "scan" in bytes
439  * @s: COMEDI subdevice.
440  *
441  * Determines the overall scan length according to the subdevice type and the
442  * number of channels in the scan for the current command.
443  *
444  * For digital input, output or input/output subdevices, samples for
445  * multiple channels are assumed to be packed into one or more unsigned
446  * short or unsigned int values according to the subdevice's %SDF_LSAMPL
447  * flag.  For other types of subdevice, samples are assumed to occupy a
448  * whole unsigned short or unsigned int according to the %SDF_LSAMPL flag.
449  *
450  * Returns the overall scan length in bytes.
451  */
comedi_bytes_per_scan(struct comedi_subdevice * s)452 unsigned int comedi_bytes_per_scan(struct comedi_subdevice *s)
453 {
454 	struct comedi_cmd *cmd = &s->async->cmd;
455 
456 	return comedi_bytes_per_scan_cmd(s, cmd);
457 }
458 EXPORT_SYMBOL_GPL(comedi_bytes_per_scan);
459 
__comedi_nscans_left(struct comedi_subdevice * s,unsigned int nscans)460 static unsigned int __comedi_nscans_left(struct comedi_subdevice *s,
461 					 unsigned int nscans)
462 {
463 	struct comedi_async *async = s->async;
464 	struct comedi_cmd *cmd = &async->cmd;
465 
466 	if (cmd->stop_src == TRIG_COUNT) {
467 		unsigned int scans_left = 0;
468 
469 		if (async->scans_done < cmd->stop_arg)
470 			scans_left = cmd->stop_arg - async->scans_done;
471 
472 		if (nscans > scans_left)
473 			nscans = scans_left;
474 	}
475 	return nscans;
476 }
477 
478 /**
479  * comedi_nscans_left() - Return the number of scans left in the command
480  * @s: COMEDI subdevice.
481  * @nscans: The expected number of scans or 0 for all available scans.
482  *
483  * If @nscans is 0, it is set to the number of scans available in the
484  * async buffer.
485  *
486  * If the async command has a stop_src of %TRIG_COUNT, the @nscans will be
487  * checked against the number of scans remaining to complete the command.
488  *
489  * The return value will then be either the expected number of scans or the
490  * number of scans remaining to complete the command, whichever is fewer.
491  */
comedi_nscans_left(struct comedi_subdevice * s,unsigned int nscans)492 unsigned int comedi_nscans_left(struct comedi_subdevice *s,
493 				unsigned int nscans)
494 {
495 	if (nscans == 0) {
496 		unsigned int nbytes = comedi_buf_read_n_available(s);
497 
498 		nscans = nbytes / comedi_bytes_per_scan(s);
499 	}
500 	return __comedi_nscans_left(s, nscans);
501 }
502 EXPORT_SYMBOL_GPL(comedi_nscans_left);
503 
504 /**
505  * comedi_nsamples_left() - Return the number of samples left in the command
506  * @s: COMEDI subdevice.
507  * @nsamples: The expected number of samples.
508  *
509  * Returns the number of samples remaining to complete the command, or the
510  * specified expected number of samples (@nsamples), whichever is fewer.
511  */
comedi_nsamples_left(struct comedi_subdevice * s,unsigned int nsamples)512 unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
513 				  unsigned int nsamples)
514 {
515 	struct comedi_async *async = s->async;
516 	struct comedi_cmd *cmd = &async->cmd;
517 	unsigned long long scans_left;
518 	unsigned long long samples_left;
519 
520 	if (cmd->stop_src != TRIG_COUNT)
521 		return nsamples;
522 
523 	scans_left = __comedi_nscans_left(s, cmd->stop_arg);
524 	if (!scans_left)
525 		return 0;
526 
527 	samples_left = scans_left * cmd->scan_end_arg -
528 		comedi_bytes_to_samples(s, async->scan_progress);
529 
530 	if (samples_left < nsamples)
531 		return samples_left;
532 	return nsamples;
533 }
534 EXPORT_SYMBOL_GPL(comedi_nsamples_left);
535 
536 /**
537  * comedi_inc_scan_progress() - Update scan progress in asynchronous command
538  * @s: COMEDI subdevice.
539  * @num_bytes: Amount of data in bytes to increment scan progress.
540  *
541  * Increments the scan progress by the number of bytes specified by @num_bytes.
542  * If the scan progress reaches or exceeds the scan length in bytes, reduce
543  * it modulo the scan length in bytes and set the "end of scan" asynchronous
544  * event flag (%COMEDI_CB_EOS) to be processed later.
545  */
comedi_inc_scan_progress(struct comedi_subdevice * s,unsigned int num_bytes)546 void comedi_inc_scan_progress(struct comedi_subdevice *s,
547 			      unsigned int num_bytes)
548 {
549 	struct comedi_async *async = s->async;
550 	struct comedi_cmd *cmd = &async->cmd;
551 	unsigned int scan_length = comedi_bytes_per_scan(s);
552 
553 	/* track the 'cur_chan' for non-SDF_PACKED subdevices */
554 	if (!(s->subdev_flags & SDF_PACKED)) {
555 		async->cur_chan += comedi_bytes_to_samples(s, num_bytes);
556 		async->cur_chan %= cmd->chanlist_len;
557 	}
558 
559 	async->scan_progress += num_bytes;
560 	if (async->scan_progress >= scan_length) {
561 		unsigned int nscans = async->scan_progress / scan_length;
562 
563 		if (async->scans_done < (UINT_MAX - nscans))
564 			async->scans_done += nscans;
565 		else
566 			async->scans_done = UINT_MAX;
567 
568 		async->scan_progress %= scan_length;
569 		async->events |= COMEDI_CB_EOS;
570 	}
571 }
572 EXPORT_SYMBOL_GPL(comedi_inc_scan_progress);
573 
574 /**
575  * comedi_handle_events() - Handle events and possibly stop acquisition
576  * @dev: COMEDI device.
577  * @s: COMEDI subdevice.
578  *
579  * Handles outstanding asynchronous acquisition event flags associated
580  * with the subdevice.  Call the subdevice's @s->cancel() handler if the
581  * "end of acquisition", "error" or "overflow" event flags are set in order
582  * to stop the acquisition at the driver level.
583  *
584  * Calls comedi_event() to further process the event flags, which may mark
585  * the asynchronous command as no longer running, possibly terminated with
586  * an error, and may wake up tasks.
587  *
588  * Return a bit-mask of the handled events.
589  */
comedi_handle_events(struct comedi_device * dev,struct comedi_subdevice * s)590 unsigned int comedi_handle_events(struct comedi_device *dev,
591 				  struct comedi_subdevice *s)
592 {
593 	unsigned int events = s->async->events;
594 
595 	if (events == 0)
596 		return events;
597 
598 	if ((events & COMEDI_CB_CANCEL_MASK) && s->cancel)
599 		s->cancel(dev, s);
600 
601 	comedi_event(dev, s);
602 
603 	return events;
604 }
605 EXPORT_SYMBOL_GPL(comedi_handle_events);
606 
insn_rw_emulate_bits(struct comedi_device * dev,struct comedi_subdevice * s,struct comedi_insn * insn,unsigned int * data)607 static int insn_rw_emulate_bits(struct comedi_device *dev,
608 				struct comedi_subdevice *s,
609 				struct comedi_insn *insn,
610 				unsigned int *data)
611 {
612 	struct comedi_insn _insn;
613 	unsigned int chan = CR_CHAN(insn->chanspec);
614 	unsigned int base_chan = (chan < 32) ? 0 : chan;
615 	unsigned int _data[2];
616 	int ret;
617 
618 	memset(_data, 0, sizeof(_data));
619 	memset(&_insn, 0, sizeof(_insn));
620 	_insn.insn = INSN_BITS;
621 	_insn.chanspec = base_chan;
622 	_insn.n = 2;
623 	_insn.subdev = insn->subdev;
624 
625 	if (insn->insn == INSN_WRITE) {
626 		if (!(s->subdev_flags & SDF_WRITABLE))
627 			return -EINVAL;
628 		_data[0] = 1 << (chan - base_chan);		    /* mask */
629 		_data[1] = data[0] ? (1 << (chan - base_chan)) : 0; /* bits */
630 	}
631 
632 	ret = s->insn_bits(dev, s, &_insn, _data);
633 	if (ret < 0)
634 		return ret;
635 
636 	if (insn->insn == INSN_READ)
637 		data[0] = (_data[1] >> (chan - base_chan)) & 1;
638 
639 	return 1;
640 }
641 
__comedi_device_postconfig_async(struct comedi_device * dev,struct comedi_subdevice * s)642 static int __comedi_device_postconfig_async(struct comedi_device *dev,
643 					    struct comedi_subdevice *s)
644 {
645 	struct comedi_async *async;
646 	unsigned int buf_size;
647 	int ret;
648 
649 	lockdep_assert_held(&dev->mutex);
650 	if ((s->subdev_flags & (SDF_CMD_READ | SDF_CMD_WRITE)) == 0) {
651 		dev_warn(dev->class_dev,
652 			 "async subdevices must support SDF_CMD_READ or SDF_CMD_WRITE\n");
653 		return -EINVAL;
654 	}
655 	if (!s->do_cmdtest) {
656 		dev_warn(dev->class_dev,
657 			 "async subdevices must have a do_cmdtest() function\n");
658 		return -EINVAL;
659 	}
660 	if (!s->cancel)
661 		dev_warn(dev->class_dev,
662 			 "async subdevices should have a cancel() function\n");
663 
664 	async = kzalloc(sizeof(*async), GFP_KERNEL);
665 	if (!async)
666 		return -ENOMEM;
667 
668 	init_waitqueue_head(&async->wait_head);
669 	s->async = async;
670 
671 	async->max_bufsize = comedi_default_buf_maxsize_kb * 1024;
672 	buf_size = comedi_default_buf_size_kb * 1024;
673 	if (buf_size > async->max_bufsize)
674 		buf_size = async->max_bufsize;
675 
676 	if (comedi_buf_alloc(dev, s, buf_size) < 0) {
677 		dev_warn(dev->class_dev, "Buffer allocation failed\n");
678 		return -ENOMEM;
679 	}
680 	if (s->buf_change) {
681 		ret = s->buf_change(dev, s);
682 		if (ret < 0)
683 			return ret;
684 	}
685 
686 	comedi_alloc_subdevice_minor(s);
687 
688 	return 0;
689 }
690 
__comedi_device_postconfig(struct comedi_device * dev)691 static int __comedi_device_postconfig(struct comedi_device *dev)
692 {
693 	struct comedi_subdevice *s;
694 	int ret;
695 	int i;
696 
697 	lockdep_assert_held(&dev->mutex);
698 	if (!dev->insn_device_config)
699 		dev->insn_device_config = insn_device_inval;
700 
701 	if (!dev->get_valid_routes)
702 		dev->get_valid_routes = get_zero_valid_routes;
703 
704 	for (i = 0; i < dev->n_subdevices; i++) {
705 		s = &dev->subdevices[i];
706 
707 		if (s->type == COMEDI_SUBD_UNUSED)
708 			continue;
709 
710 		if (s->type == COMEDI_SUBD_DO) {
711 			if (s->n_chan < 32)
712 				s->io_bits = (1 << s->n_chan) - 1;
713 			else
714 				s->io_bits = 0xffffffff;
715 		}
716 
717 		if (s->len_chanlist == 0)
718 			s->len_chanlist = 1;
719 
720 		if (s->do_cmd) {
721 			ret = __comedi_device_postconfig_async(dev, s);
722 			if (ret)
723 				return ret;
724 		}
725 
726 		if (!s->range_table && !s->range_table_list)
727 			s->range_table = &range_unknown;
728 
729 		if (!s->insn_read && s->insn_bits)
730 			s->insn_read = insn_rw_emulate_bits;
731 		if (!s->insn_write && s->insn_bits)
732 			s->insn_write = insn_rw_emulate_bits;
733 
734 		if (!s->insn_read)
735 			s->insn_read = insn_inval;
736 		if (!s->insn_write)
737 			s->insn_write = insn_inval;
738 		if (!s->insn_bits)
739 			s->insn_bits = insn_inval;
740 		if (!s->insn_config)
741 			s->insn_config = insn_inval;
742 
743 		if (!s->poll)
744 			s->poll = poll_invalid;
745 	}
746 
747 	return 0;
748 }
749 
750 /* do a little post-config cleanup */
comedi_device_postconfig(struct comedi_device * dev)751 static int comedi_device_postconfig(struct comedi_device *dev)
752 {
753 	int ret;
754 
755 	lockdep_assert_held(&dev->mutex);
756 	ret = __comedi_device_postconfig(dev);
757 	if (ret < 0)
758 		return ret;
759 	down_write(&dev->attach_lock);
760 	dev->attached = true;
761 	up_write(&dev->attach_lock);
762 	return 0;
763 }
764 
765 /*
766  * Generic recognize function for drivers that register their supported
767  * board names.
768  *
769  * 'driv->board_name' points to a 'const char *' member within the
770  * zeroth element of an array of some private board information
771  * structure, say 'struct foo_board' containing a member 'const char
772  * *board_name' that is initialized to point to a board name string that
773  * is one of the candidates matched against this function's 'name'
774  * parameter.
775  *
776  * 'driv->offset' is the size of the private board information
777  * structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is
778  * the length of the array of private board information structures.
779  *
780  * If one of the board names in the array of private board information
781  * structures matches the name supplied to this function, the function
782  * returns a pointer to the pointer to the board name, otherwise it
783  * returns NULL.  The return value ends up in the 'board_ptr' member of
784  * a 'struct comedi_device' that the low-level comedi driver's
785  * 'attach()' hook can convert to a point to a particular element of its
786  * array of private board information structures by subtracting the
787  * offset of the member that points to the board name.  (No subtraction
788  * is required if the board name pointer is the first member of the
789  * private board information structure, which is generally the case.)
790  */
comedi_recognize(struct comedi_driver * driv,const char * name)791 static void *comedi_recognize(struct comedi_driver *driv, const char *name)
792 {
793 	char **name_ptr = (char **)driv->board_name;
794 	int i;
795 
796 	for (i = 0; i < driv->num_names; i++) {
797 		if (strcmp(*name_ptr, name) == 0)
798 			return name_ptr;
799 		name_ptr = (void *)name_ptr + driv->offset;
800 	}
801 
802 	return NULL;
803 }
804 
comedi_report_boards(struct comedi_driver * driv)805 static void comedi_report_boards(struct comedi_driver *driv)
806 {
807 	unsigned int i;
808 	const char *const *name_ptr;
809 
810 	pr_info("comedi: valid board names for %s driver are:\n",
811 		driv->driver_name);
812 
813 	name_ptr = driv->board_name;
814 	for (i = 0; i < driv->num_names; i++) {
815 		pr_info(" %s\n", *name_ptr);
816 		name_ptr = (const char **)((char *)name_ptr + driv->offset);
817 	}
818 
819 	if (driv->num_names == 0)
820 		pr_info(" %s\n", driv->driver_name);
821 }
822 
823 /**
824  * comedi_load_firmware() - Request and load firmware for a device
825  * @dev: COMEDI device.
826  * @device: Hardware device.
827  * @name: The name of the firmware image.
828  * @cb: Callback to the upload the firmware image.
829  * @context: Private context from the driver.
830  *
831  * Sends a firmware request for the hardware device and waits for it.  Calls
832  * the callback function to upload the firmware to the device, them releases
833  * the firmware.
834  *
835  * Returns 0 on success, -EINVAL if @cb is NULL, or a negative error number
836  * from the firmware request or the callback function.
837  */
comedi_load_firmware(struct comedi_device * dev,struct device * device,const char * name,int (* cb)(struct comedi_device * dev,const u8 * data,size_t size,unsigned long context),unsigned long context)838 int comedi_load_firmware(struct comedi_device *dev,
839 			 struct device *device,
840 			 const char *name,
841 			 int (*cb)(struct comedi_device *dev,
842 				   const u8 *data, size_t size,
843 				   unsigned long context),
844 			 unsigned long context)
845 {
846 	const struct firmware *fw;
847 	int ret;
848 
849 	if (!cb)
850 		return -EINVAL;
851 
852 	ret = request_firmware(&fw, name, device);
853 	if (ret == 0) {
854 		ret = cb(dev, fw->data, fw->size, context);
855 		release_firmware(fw);
856 	}
857 
858 	return min(ret, 0);
859 }
860 EXPORT_SYMBOL_GPL(comedi_load_firmware);
861 
862 /**
863  * __comedi_request_region() - Request an I/O region for a legacy driver
864  * @dev: COMEDI device.
865  * @start: Base address of the I/O region.
866  * @len: Length of the I/O region.
867  *
868  * Requests the specified I/O port region which must start at a non-zero
869  * address.
870  *
871  * Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request
872  * fails.
873  */
__comedi_request_region(struct comedi_device * dev,unsigned long start,unsigned long len)874 int __comedi_request_region(struct comedi_device *dev,
875 			    unsigned long start, unsigned long len)
876 {
877 	if (!start) {
878 		dev_warn(dev->class_dev,
879 			 "%s: a I/O base address must be specified\n",
880 			 dev->board_name);
881 		return -EINVAL;
882 	}
883 
884 	if (!request_region(start, len, dev->board_name)) {
885 		dev_warn(dev->class_dev, "%s: I/O port conflict (%#lx,%lu)\n",
886 			 dev->board_name, start, len);
887 		return -EIO;
888 	}
889 
890 	return 0;
891 }
892 EXPORT_SYMBOL_GPL(__comedi_request_region);
893 
894 /**
895  * comedi_request_region() - Request an I/O region for a legacy driver
896  * @dev: COMEDI device.
897  * @start: Base address of the I/O region.
898  * @len: Length of the I/O region.
899  *
900  * Requests the specified I/O port region which must start at a non-zero
901  * address.
902  *
903  * On success, @dev->iobase is set to the base address of the region and
904  * @dev->iolen is set to its length.
905  *
906  * Returns 0 on success, -EINVAL if @start is 0, or -EIO if the request
907  * fails.
908  */
comedi_request_region(struct comedi_device * dev,unsigned long start,unsigned long len)909 int comedi_request_region(struct comedi_device *dev,
910 			  unsigned long start, unsigned long len)
911 {
912 	int ret;
913 
914 	ret = __comedi_request_region(dev, start, len);
915 	if (ret == 0) {
916 		dev->iobase = start;
917 		dev->iolen = len;
918 	}
919 
920 	return ret;
921 }
922 EXPORT_SYMBOL_GPL(comedi_request_region);
923 
924 /**
925  * comedi_legacy_detach() - A generic (*detach) function for legacy drivers
926  * @dev: COMEDI device.
927  *
928  * This is a simple, generic 'detach' handler for legacy COMEDI devices that
929  * just use a single I/O port region and possibly an IRQ and that don't need
930  * any special clean-up for their private device or subdevice storage.  It
931  * can also be called by a driver-specific 'detach' handler.
932  *
933  * If @dev->irq is non-zero, the IRQ will be freed.  If @dev->iobase and
934  * @dev->iolen are both non-zero, the I/O port region will be released.
935  */
comedi_legacy_detach(struct comedi_device * dev)936 void comedi_legacy_detach(struct comedi_device *dev)
937 {
938 	if (dev->irq) {
939 		free_irq(dev->irq, dev);
940 		dev->irq = 0;
941 	}
942 	if (dev->iobase && dev->iolen) {
943 		release_region(dev->iobase, dev->iolen);
944 		dev->iobase = 0;
945 		dev->iolen = 0;
946 	}
947 }
948 EXPORT_SYMBOL_GPL(comedi_legacy_detach);
949 
comedi_device_attach(struct comedi_device * dev,struct comedi_devconfig * it)950 int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
951 {
952 	struct comedi_driver *driv;
953 	int ret;
954 
955 	lockdep_assert_held(&dev->mutex);
956 	if (dev->attached)
957 		return -EBUSY;
958 
959 	mutex_lock(&comedi_drivers_list_lock);
960 	for (driv = comedi_drivers; driv; driv = driv->next) {
961 		if (!try_module_get(driv->module))
962 			continue;
963 		if (driv->num_names) {
964 			dev->board_ptr = comedi_recognize(driv, it->board_name);
965 			if (dev->board_ptr)
966 				break;
967 		} else if (strcmp(driv->driver_name, it->board_name) == 0) {
968 			break;
969 		}
970 		module_put(driv->module);
971 	}
972 	if (!driv) {
973 		/*  recognize has failed if we get here */
974 		/*  report valid board names before returning error */
975 		for (driv = comedi_drivers; driv; driv = driv->next) {
976 			if (!try_module_get(driv->module))
977 				continue;
978 			comedi_report_boards(driv);
979 			module_put(driv->module);
980 		}
981 		ret = -EIO;
982 		goto out;
983 	}
984 	if (!driv->attach) {
985 		/* driver does not support manual configuration */
986 		dev_warn(dev->class_dev,
987 			 "driver '%s' does not support attach using comedi_config\n",
988 			 driv->driver_name);
989 		module_put(driv->module);
990 		ret = -EIO;
991 		goto out;
992 	}
993 	dev->driver = driv;
994 	dev->board_name = dev->board_ptr ? *(const char **)dev->board_ptr
995 					 : dev->driver->driver_name;
996 	ret = driv->attach(dev, it);
997 	if (ret >= 0)
998 		ret = comedi_device_postconfig(dev);
999 	if (ret < 0) {
1000 		comedi_device_detach(dev);
1001 		module_put(driv->module);
1002 	}
1003 	/* On success, the driver module count has been incremented. */
1004 out:
1005 	mutex_unlock(&comedi_drivers_list_lock);
1006 	return ret;
1007 }
1008 
1009 /**
1010  * comedi_auto_config() - Create a COMEDI device for a hardware device
1011  * @hardware_device: Hardware device.
1012  * @driver: COMEDI low-level driver for the hardware device.
1013  * @context: Driver context for the auto_attach handler.
1014  *
1015  * Allocates a new COMEDI device for the hardware device and calls the
1016  * low-level driver's 'auto_attach' handler to set-up the hardware and
1017  * allocate the COMEDI subdevices.  Additional "post-configuration" setting
1018  * up is performed on successful return from the 'auto_attach' handler.
1019  * If the 'auto_attach' handler fails, the low-level driver's 'detach'
1020  * handler will be called as part of the clean-up.
1021  *
1022  * This is usually called from a wrapper function in a bus-specific COMEDI
1023  * module, which in turn is usually called from a bus device 'probe'
1024  * function in the low-level driver.
1025  *
1026  * Returns 0 on success, -EINVAL if the parameters are invalid or the
1027  * post-configuration determines the driver has set the COMEDI device up
1028  * incorrectly, -ENOMEM if failed to allocate memory, -EBUSY if run out of
1029  * COMEDI minor device numbers, or some negative error number returned by
1030  * the driver's 'auto_attach' handler.
1031  */
comedi_auto_config(struct device * hardware_device,struct comedi_driver * driver,unsigned long context)1032 int comedi_auto_config(struct device *hardware_device,
1033 		       struct comedi_driver *driver, unsigned long context)
1034 {
1035 	struct comedi_device *dev;
1036 	int ret;
1037 
1038 	if (!hardware_device) {
1039 		pr_warn("BUG! %s called with NULL hardware_device\n", __func__);
1040 		return -EINVAL;
1041 	}
1042 	if (!driver) {
1043 		dev_warn(hardware_device,
1044 			 "BUG! %s called with NULL comedi driver\n", __func__);
1045 		return -EINVAL;
1046 	}
1047 
1048 	if (!driver->auto_attach) {
1049 		dev_warn(hardware_device,
1050 			 "BUG! comedi driver '%s' has no auto_attach handler\n",
1051 			 driver->driver_name);
1052 		return -EINVAL;
1053 	}
1054 
1055 	dev = comedi_alloc_board_minor(hardware_device);
1056 	if (IS_ERR(dev)) {
1057 		dev_warn(hardware_device,
1058 			 "driver '%s' could not create device.\n",
1059 			 driver->driver_name);
1060 		return PTR_ERR(dev);
1061 	}
1062 	/* Note: comedi_alloc_board_minor() locked dev->mutex. */
1063 	lockdep_assert_held(&dev->mutex);
1064 
1065 	dev->driver = driver;
1066 	dev->board_name = dev->driver->driver_name;
1067 	ret = driver->auto_attach(dev, context);
1068 	if (ret >= 0)
1069 		ret = comedi_device_postconfig(dev);
1070 
1071 	if (ret < 0) {
1072 		dev_warn(hardware_device,
1073 			 "driver '%s' failed to auto-configure device.\n",
1074 			 driver->driver_name);
1075 		mutex_unlock(&dev->mutex);
1076 		comedi_release_hardware_device(hardware_device);
1077 	} else {
1078 		/*
1079 		 * class_dev should be set properly here
1080 		 *  after a successful auto config
1081 		 */
1082 		dev_info(dev->class_dev,
1083 			 "driver '%s' has successfully auto-configured '%s'.\n",
1084 			 driver->driver_name, dev->board_name);
1085 		mutex_unlock(&dev->mutex);
1086 	}
1087 	return ret;
1088 }
1089 EXPORT_SYMBOL_GPL(comedi_auto_config);
1090 
1091 /**
1092  * comedi_auto_unconfig() - Unconfigure auto-allocated COMEDI device
1093  * @hardware_device: Hardware device previously passed to
1094  *                   comedi_auto_config().
1095  *
1096  * Cleans up and eventually destroys the COMEDI device allocated by
1097  * comedi_auto_config() for the same hardware device.  As part of this
1098  * clean-up, the low-level COMEDI driver's 'detach' handler will be called.
1099  * (The COMEDI device itself will persist in an unattached state if it is
1100  * still open, until it is released, and any mmapped buffers will persist
1101  * until they are munmapped.)
1102  *
1103  * This is usually called from a wrapper module in a bus-specific COMEDI
1104  * module, which in turn is usually set as the bus device 'remove' function
1105  * in the low-level COMEDI driver.
1106  */
comedi_auto_unconfig(struct device * hardware_device)1107 void comedi_auto_unconfig(struct device *hardware_device)
1108 {
1109 	if (!hardware_device)
1110 		return;
1111 	comedi_release_hardware_device(hardware_device);
1112 }
1113 EXPORT_SYMBOL_GPL(comedi_auto_unconfig);
1114 
1115 /**
1116  * comedi_driver_register() - Register a low-level COMEDI driver
1117  * @driver: Low-level COMEDI driver.
1118  *
1119  * The low-level COMEDI driver is added to the list of registered COMEDI
1120  * drivers.  This is used by the handler for the "/proc/comedi" file and is
1121  * also used by the handler for the %COMEDI_DEVCONFIG ioctl to configure
1122  * "legacy" COMEDI devices (for those low-level drivers that support it).
1123  *
1124  * Returns 0.
1125  */
comedi_driver_register(struct comedi_driver * driver)1126 int comedi_driver_register(struct comedi_driver *driver)
1127 {
1128 	mutex_lock(&comedi_drivers_list_lock);
1129 	driver->next = comedi_drivers;
1130 	comedi_drivers = driver;
1131 	mutex_unlock(&comedi_drivers_list_lock);
1132 
1133 	return 0;
1134 }
1135 EXPORT_SYMBOL_GPL(comedi_driver_register);
1136 
1137 /**
1138  * comedi_driver_unregister() - Unregister a low-level COMEDI driver
1139  * @driver: Low-level COMEDI driver.
1140  *
1141  * The low-level COMEDI driver is removed from the list of registered COMEDI
1142  * drivers.  Detaches any COMEDI devices attached to the driver, which will
1143  * result in the low-level driver's 'detach' handler being called for those
1144  * devices before this function returns.
1145  */
comedi_driver_unregister(struct comedi_driver * driver)1146 void comedi_driver_unregister(struct comedi_driver *driver)
1147 {
1148 	struct comedi_driver *prev;
1149 	int i;
1150 
1151 	/* unlink the driver */
1152 	mutex_lock(&comedi_drivers_list_lock);
1153 	if (comedi_drivers == driver) {
1154 		comedi_drivers = driver->next;
1155 	} else {
1156 		for (prev = comedi_drivers; prev->next; prev = prev->next) {
1157 			if (prev->next == driver) {
1158 				prev->next = driver->next;
1159 				break;
1160 			}
1161 		}
1162 	}
1163 	mutex_unlock(&comedi_drivers_list_lock);
1164 
1165 	/* check for devices using this driver */
1166 	for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
1167 		struct comedi_device *dev = comedi_dev_get_from_minor(i);
1168 
1169 		if (!dev)
1170 			continue;
1171 
1172 		mutex_lock(&dev->mutex);
1173 		if (dev->attached && dev->driver == driver) {
1174 			if (dev->use_count)
1175 				dev_warn(dev->class_dev,
1176 					 "BUG! detaching device with use_count=%d\n",
1177 					 dev->use_count);
1178 			comedi_device_detach(dev);
1179 		}
1180 		mutex_unlock(&dev->mutex);
1181 		comedi_dev_put(dev);
1182 	}
1183 }
1184 EXPORT_SYMBOL_GPL(comedi_driver_unregister);
1185