1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * comedidev.h
4  * header file for kernel-only structures, variables, and constants
5  *
6  * COMEDI - Linux Control and Measurement Device Interface
7  * Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
8  */
9 
10 #ifndef _COMEDIDEV_H
11 #define _COMEDIDEV_H
12 
13 #include <linux/dma-mapping.h>
14 #include <linux/mutex.h>
15 #include <linux/spinlock_types.h>
16 #include <linux/rwsem.h>
17 #include <linux/kref.h>
18 #include <linux/comedi.h>
19 
20 #define COMEDI_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + (c))
21 #define COMEDI_VERSION_CODE COMEDI_VERSION(COMEDI_MAJORVERSION, \
22 	COMEDI_MINORVERSION, COMEDI_MICROVERSION)
23 #define COMEDI_RELEASE VERSION
24 
25 #define COMEDI_NUM_BOARD_MINORS 0x30
26 
27 /**
28  * struct comedi_subdevice - Working data for a COMEDI subdevice
29  * @device: COMEDI device to which this subdevice belongs.  (Initialized by
30  *	comedi_alloc_subdevices().)
31  * @index: Index of this subdevice within device's array of subdevices.
32  *	(Initialized by comedi_alloc_subdevices().)
33  * @type: Type of subdevice from &enum comedi_subdevice_type.  (Initialized by
34  *	the low-level driver.)
35  * @n_chan: Number of channels the subdevice supports.  (Initialized by the
36  *	low-level driver.)
37  * @subdev_flags: Various "SDF" flags indicating aspects of the subdevice to
38  *	the COMEDI core and user application.  (Initialized by the low-level
39  *	driver.)
40  * @len_chanlist: Maximum length of a channel list if the subdevice supports
41  *	asynchronous acquisition commands.  (Optionally initialized by the
42  *	low-level driver, or changed from 0 to 1 during post-configuration.)
43  * @private: Private data pointer which is either set by the low-level driver
44  *	itself, or by a call to comedi_alloc_spriv() which allocates storage.
45  *	In the latter case, the storage is automatically freed after the
46  *	low-level driver's "detach" handler is called for the device.
47  *	(Initialized by the low-level driver.)
48  * @async: Pointer to &struct comedi_async id the subdevice supports
49  *	asynchronous acquisition commands.  (Allocated and initialized during
50  *	post-configuration if needed.)
51  * @lock: Pointer to a file object that performed a %COMEDI_LOCK ioctl on the
52  *	subdevice.  (Initially NULL.)
53  * @busy: Pointer to a file object that is performing an asynchronous
54  *	acquisition command on the subdevice.  (Initially NULL.)
55  * @runflags: Internal flags for use by COMEDI core, mostly indicating whether
56  *	an asynchronous acquisition command is running.
57  * @spin_lock: Generic spin-lock for use by the COMEDI core and the low-level
58  *	driver.  (Initialized by comedi_alloc_subdevices().)
59  * @io_bits: Bit-mask indicating the channel directions for a DIO subdevice
60  *	with no more than 32 channels.  A '1' at a bit position indicates the
61  *	corresponding channel is configured as an output.  (Initialized by the
62  *	low-level driver for a DIO subdevice.  Forced to all-outputs during
63  *	post-configuration for a digital output subdevice.)
64  * @maxdata: If non-zero, this is the maximum raw data value of each channel.
65  *	If zero, the maximum data value is channel-specific.  (Initialized by
66  *	the low-level driver.)
67  * @maxdata_list: If the maximum data value is channel-specific, this points
68  *	to an array of maximum data values indexed by channel index.
69  *	(Initialized by the low-level driver.)
70  * @range_table: If non-NULL, this points to a COMEDI range table for the
71  *	subdevice.  If NULL, the range table is channel-specific.  (Initialized
72  *	by the low-level driver, will be set to an "invalid" range table during
73  *	post-configuration if @range_table and @range_table_list are both
74  *	NULL.)
75  * @range_table_list: If the COMEDI range table is channel-specific, this
76  *	points to an array of pointers to COMEDI range tables indexed by
77  *	channel number.  (Initialized by the low-level driver.)
78  * @chanlist: Not used.
79  * @insn_read: Optional pointer to a handler for the %INSN_READ instruction.
80  *	(Initialized by the low-level driver, or set to a default handler
81  *	during post-configuration.)
82  * @insn_write: Optional pointer to a handler for the %INSN_WRITE instruction.
83  *	(Initialized by the low-level driver, or set to a default handler
84  *	during post-configuration.)
85  * @insn_bits: Optional pointer to a handler for the %INSN_BITS instruction
86  *	for a digital input, digital output or digital input/output subdevice.
87  *	(Initialized by the low-level driver, or set to a default handler
88  *	during post-configuration.)
89  * @insn_config: Optional pointer to a handler for the %INSN_CONFIG
90  *	instruction.  (Initialized by the low-level driver, or set to a default
91  *	handler during post-configuration.)
92  * @do_cmd: If the subdevice supports asynchronous acquisition commands, this
93  *	points to a handler to set it up in hardware.  (Initialized by the
94  *	low-level driver.)
95  * @do_cmdtest: If the subdevice supports asynchronous acquisition commands,
96  *	this points to a handler used to check and possibly tweak a prospective
97  *	acquisition command without setting it up in hardware.  (Initialized by
98  *	the low-level driver.)
99  * @poll: If the subdevice supports asynchronous acquisition commands, this
100  *	is an optional pointer to a handler for the %COMEDI_POLL ioctl which
101  *	instructs the low-level driver to synchronize buffers.  (Initialized by
102  *	the low-level driver if needed.)
103  * @cancel: If the subdevice supports asynchronous acquisition commands, this
104  *	points to a handler used to terminate a running command.  (Initialized
105  *	by the low-level driver.)
106  * @buf_change: If the subdevice supports asynchronous acquisition commands,
107  *	this is an optional pointer to a handler that is called when the data
108  *	buffer for handling asynchronous commands is allocated or reallocated.
109  *	(Initialized by the low-level driver if needed.)
110  * @munge: If the subdevice supports asynchronous acquisition commands and
111  *	uses DMA to transfer data from the hardware to the acquisition buffer,
112  *	this points to a function used to "munge" the data values from the
113  *	hardware into the format expected by COMEDI.  (Initialized by the
114  *	low-level driver if needed.)
115  * @async_dma_dir: If the subdevice supports asynchronous acquisition commands
116  *	and uses DMA to transfer data from the hardware to the acquisition
117  *	buffer, this sets the DMA direction for the buffer. (initialized to
118  *	%DMA_NONE by comedi_alloc_subdevices() and changed by the low-level
119  *	driver if necessary.)
120  * @state: Handy bit-mask indicating the output states for a DIO or digital
121  *	output subdevice with no more than 32 channels. (Initialized by the
122  *	low-level driver.)
123  * @class_dev: If the subdevice supports asynchronous acquisition commands,
124  *	this points to a sysfs comediX_subdY device where X is the minor device
125  *	number of the COMEDI device and Y is the subdevice number.  The minor
126  *	device number for the sysfs device is allocated dynamically in the
127  *	range 48 to 255.  This is used to allow the COMEDI device to be opened
128  *	with a different default read or write subdevice.  (Allocated during
129  *	post-configuration if needed.)
130  * @minor: If @class_dev is set, this is its dynamically allocated minor
131  *	device number.  (Set during post-configuration if necessary.)
132  * @readback: Optional pointer to memory allocated by
133  *	comedi_alloc_subdev_readback() used to hold the values written to
134  *	analog output channels so they can be read back.  The storage is
135  *	automatically freed after the low-level driver's "detach" handler is
136  *	called for the device.  (Initialized by the low-level driver.)
137  *
138  * This is the main control structure for a COMEDI subdevice.  If the subdevice
139  * supports asynchronous acquisition commands, additional information is stored
140  * in the &struct comedi_async pointed to by @async.
141  *
142  * Most of the subdevice is initialized by the low-level driver's "attach" or
143  * "auto_attach" handlers but parts of it are initialized by
144  * comedi_alloc_subdevices(), and other parts are initialized during
145  * post-configuration on return from that handler.
146  *
147  * A low-level driver that sets @insn_bits for a digital input, digital output,
148  * or DIO subdevice may leave @insn_read and @insn_write uninitialized, in
149  * which case they will be set to a default handler during post-configuration
150  * that uses @insn_bits to emulate the %INSN_READ and %INSN_WRITE instructions.
151  */
152 struct comedi_subdevice {
153 	struct comedi_device *device;
154 	int index;
155 	int type;
156 	int n_chan;
157 	int subdev_flags;
158 	int len_chanlist;	/* maximum length of channel/gain list */
159 
160 	void *private;
161 
162 	struct comedi_async *async;
163 
164 	void *lock;
165 	void *busy;
166 	unsigned int runflags;
167 	spinlock_t spin_lock;	/* generic spin-lock for COMEDI and drivers */
168 
169 	unsigned int io_bits;
170 
171 	unsigned int maxdata;	/* if maxdata==0, use list */
172 	const unsigned int *maxdata_list;	/* list is channel specific */
173 
174 	const struct comedi_lrange *range_table;
175 	const struct comedi_lrange *const *range_table_list;
176 
177 	unsigned int *chanlist;	/* driver-owned chanlist (not used) */
178 
179 	int (*insn_read)(struct comedi_device *dev, struct comedi_subdevice *s,
180 			 struct comedi_insn *insn, unsigned int *data);
181 	int (*insn_write)(struct comedi_device *dev, struct comedi_subdevice *s,
182 			  struct comedi_insn *insn, unsigned int *data);
183 	int (*insn_bits)(struct comedi_device *dev, struct comedi_subdevice *s,
184 			 struct comedi_insn *insn, unsigned int *data);
185 	int (*insn_config)(struct comedi_device *dev,
186 			   struct comedi_subdevice *s,
187 			   struct comedi_insn *insn,
188 			   unsigned int *data);
189 
190 	int (*do_cmd)(struct comedi_device *dev, struct comedi_subdevice *s);
191 	int (*do_cmdtest)(struct comedi_device *dev,
192 			  struct comedi_subdevice *s,
193 			  struct comedi_cmd *cmd);
194 	int (*poll)(struct comedi_device *dev, struct comedi_subdevice *s);
195 	int (*cancel)(struct comedi_device *dev, struct comedi_subdevice *s);
196 
197 	/* called when the buffer changes */
198 	int (*buf_change)(struct comedi_device *dev,
199 			  struct comedi_subdevice *s);
200 
201 	void (*munge)(struct comedi_device *dev, struct comedi_subdevice *s,
202 		      void *data, unsigned int num_bytes,
203 		      unsigned int start_chan_index);
204 	enum dma_data_direction async_dma_dir;
205 
206 	unsigned int state;
207 
208 	struct device *class_dev;
209 	int minor;
210 
211 	unsigned int *readback;
212 };
213 
214 /**
215  * struct comedi_buf_page - Describe a page of a COMEDI buffer
216  * @virt_addr: Kernel address of page.
217  * @dma_addr: DMA address of page if in DMA coherent memory.
218  */
219 struct comedi_buf_page {
220 	void *virt_addr;
221 	dma_addr_t dma_addr;
222 };
223 
224 /**
225  * struct comedi_buf_map - Describe pages in a COMEDI buffer
226  * @dma_hw_dev: Low-level hardware &struct device pointer copied from the
227  *	COMEDI device's hw_dev member.
228  * @page_list: Pointer to array of &struct comedi_buf_page, one for each
229  *	page in the buffer.
230  * @n_pages: Number of pages in the buffer.
231  * @dma_dir: DMA direction used to allocate pages of DMA coherent memory,
232  *	or %DMA_NONE if pages allocated from regular memory.
233  * @refcount: &struct kref reference counter used to free the buffer.
234  *
235  * A COMEDI data buffer is allocated as individual pages, either in
236  * conventional memory or DMA coherent memory, depending on the attached,
237  * low-level hardware device.  (The buffer pages also get mapped into the
238  * kernel's contiguous virtual address space pointed to by the 'prealloc_buf'
239  * member of &struct comedi_async.)
240  *
241  * The buffer is normally freed when the COMEDI device is detached from the
242  * low-level driver (which may happen due to device removal), but if it happens
243  * to be mmapped at the time, the pages cannot be freed until the buffer has
244  * been munmapped.  That is what the reference counter is for.  (The virtual
245  * address space pointed by 'prealloc_buf' is freed when the COMEDI device is
246  * detached.)
247  */
248 struct comedi_buf_map {
249 	struct device *dma_hw_dev;
250 	struct comedi_buf_page *page_list;
251 	unsigned int n_pages;
252 	enum dma_data_direction dma_dir;
253 	struct kref refcount;
254 };
255 
256 /**
257  * struct comedi_async - Control data for asynchronous COMEDI commands
258  * @prealloc_buf: Kernel virtual address of allocated acquisition buffer.
259  * @prealloc_bufsz: Buffer size (in bytes).
260  * @buf_map: Map of buffer pages.
261  * @max_bufsize: Maximum allowed buffer size (in bytes).
262  * @buf_write_count: "Write completed" count (in bytes, modulo 2**32).
263  * @buf_write_alloc_count: "Allocated for writing" count (in bytes,
264  *	modulo 2**32).
265  * @buf_read_count: "Read completed" count (in bytes, modulo 2**32).
266  * @buf_read_alloc_count: "Allocated for reading" count (in bytes,
267  *	modulo 2**32).
268  * @buf_write_ptr: Buffer position for writer.
269  * @buf_read_ptr: Buffer position for reader.
270  * @cur_chan: Current position in chanlist for scan (for those drivers that
271  *	use it).
272  * @scans_done: The number of scans completed.
273  * @scan_progress: Amount received or sent for current scan (in bytes).
274  * @munge_chan: Current position in chanlist for "munging".
275  * @munge_count: "Munge" count (in bytes, modulo 2**32).
276  * @munge_ptr: Buffer position for "munging".
277  * @events: Bit-vector of events that have occurred.
278  * @cmd: Details of comedi command in progress.
279  * @wait_head: Task wait queue for file reader or writer.
280  * @cb_mask: Bit-vector of events that should wake waiting tasks.
281  * @inttrig: Software trigger function for command, or NULL.
282  *
283  * Note about the ..._count and ..._ptr members:
284  *
285  * Think of the _Count values being integers of unlimited size, indexing
286  * into a buffer of infinite length (though only an advancing portion
287  * of the buffer of fixed length prealloc_bufsz is accessible at any
288  * time).  Then:
289  *
290  *   Buf_Read_Count <= Buf_Read_Alloc_Count <= Munge_Count <=
291  *   Buf_Write_Count <= Buf_Write_Alloc_Count <=
292  *   (Buf_Read_Count + prealloc_bufsz)
293  *
294  * (Those aren't the actual members, apart from prealloc_bufsz.) When the
295  * buffer is reset, those _Count values start at 0 and only increase in value,
296  * maintaining the above inequalities until the next time the buffer is
297  * reset.  The buffer is divided into the following regions by the inequalities:
298  *
299  *   [0, Buf_Read_Count):
300  *     old region no longer accessible
301  *
302  *   [Buf_Read_Count, Buf_Read_Alloc_Count):
303  *     filled and munged region allocated for reading but not yet read
304  *
305  *   [Buf_Read_Alloc_Count, Munge_Count):
306  *     filled and munged region not yet allocated for reading
307  *
308  *   [Munge_Count, Buf_Write_Count):
309  *     filled region not yet munged
310  *
311  *   [Buf_Write_Count, Buf_Write_Alloc_Count):
312  *     unfilled region allocated for writing but not yet written
313  *
314  *   [Buf_Write_Alloc_Count, Buf_Read_Count + prealloc_bufsz):
315  *     unfilled region not yet allocated for writing
316  *
317  *   [Buf_Read_Count + prealloc_bufsz, infinity):
318  *     unfilled region not yet accessible
319  *
320  * Data needs to be written into the buffer before it can be read out,
321  * and may need to be converted (or "munged") between the two
322  * operations.  Extra unfilled buffer space may need to allocated for
323  * writing (advancing Buf_Write_Alloc_Count) before new data is written.
324  * After writing new data, the newly filled space needs to be released
325  * (advancing Buf_Write_Count).  This also results in the new data being
326  * "munged" (advancing Munge_Count).  Before data is read out of the
327  * buffer, extra space may need to be allocated for reading (advancing
328  * Buf_Read_Alloc_Count).  After the data has been read out, the space
329  * needs to be released (advancing Buf_Read_Count).
330  *
331  * The actual members, buf_read_count, buf_read_alloc_count,
332  * munge_count, buf_write_count, and buf_write_alloc_count take the
333  * value of the corresponding capitalized _Count values modulo 2^32
334  * (UINT_MAX+1).  Subtracting a "higher" _count value from a "lower"
335  * _count value gives the same answer as subtracting a "higher" _Count
336  * value from a lower _Count value because prealloc_bufsz < UINT_MAX+1.
337  * The modulo operation is done implicitly.
338  *
339  * The buf_read_ptr, munge_ptr, and buf_write_ptr members take the value
340  * of the corresponding capitalized _Count values modulo prealloc_bufsz.
341  * These correspond to byte indices in the physical buffer.  The modulo
342  * operation is done by subtracting prealloc_bufsz when the value
343  * exceeds prealloc_bufsz (assuming prealloc_bufsz plus the increment is
344  * less than or equal to UINT_MAX).
345  */
346 struct comedi_async {
347 	void *prealloc_buf;
348 	unsigned int prealloc_bufsz;
349 	struct comedi_buf_map *buf_map;
350 	unsigned int max_bufsize;
351 	unsigned int buf_write_count;
352 	unsigned int buf_write_alloc_count;
353 	unsigned int buf_read_count;
354 	unsigned int buf_read_alloc_count;
355 	unsigned int buf_write_ptr;
356 	unsigned int buf_read_ptr;
357 	unsigned int cur_chan;
358 	unsigned int scans_done;
359 	unsigned int scan_progress;
360 	unsigned int munge_chan;
361 	unsigned int munge_count;
362 	unsigned int munge_ptr;
363 	unsigned int events;
364 	struct comedi_cmd cmd;
365 	wait_queue_head_t wait_head;
366 	unsigned int cb_mask;
367 	int (*inttrig)(struct comedi_device *dev, struct comedi_subdevice *s,
368 		       unsigned int x);
369 };
370 
371 /**
372  * enum comedi_cb - &struct comedi_async callback "events"
373  * @COMEDI_CB_EOS:		end-of-scan
374  * @COMEDI_CB_EOA:		end-of-acquisition/output
375  * @COMEDI_CB_BLOCK:		data has arrived, wakes up read() / write()
376  * @COMEDI_CB_EOBUF:		DEPRECATED: end of buffer
377  * @COMEDI_CB_ERROR:		card error during acquisition
378  * @COMEDI_CB_OVERFLOW:		buffer overflow/underflow
379  * @COMEDI_CB_ERROR_MASK:	events that indicate an error has occurred
380  * @COMEDI_CB_CANCEL_MASK:	events that will cancel an async command
381  */
382 enum comedi_cb {
383 	COMEDI_CB_EOS		= BIT(0),
384 	COMEDI_CB_EOA		= BIT(1),
385 	COMEDI_CB_BLOCK		= BIT(2),
386 	COMEDI_CB_EOBUF		= BIT(3),
387 	COMEDI_CB_ERROR		= BIT(4),
388 	COMEDI_CB_OVERFLOW	= BIT(5),
389 	/* masks */
390 	COMEDI_CB_ERROR_MASK	= (COMEDI_CB_ERROR | COMEDI_CB_OVERFLOW),
391 	COMEDI_CB_CANCEL_MASK	= (COMEDI_CB_EOA | COMEDI_CB_ERROR_MASK)
392 };
393 
394 /**
395  * struct comedi_driver - COMEDI driver registration
396  * @driver_name: Name of driver.
397  * @module: Owning module.
398  * @attach: The optional "attach" handler for manually configured COMEDI
399  *	devices.
400  * @detach: The "detach" handler for deconfiguring COMEDI devices.
401  * @auto_attach: The optional "auto_attach" handler for automatically
402  *	configured COMEDI devices.
403  * @num_names: Optional number of "board names" supported.
404  * @board_name: Optional pointer to a pointer to a board name.  The pointer
405  *	to a board name is embedded in an element of a driver-defined array
406  *	of static, read-only board type information.
407  * @offset: Optional size of each element of the driver-defined array of
408  *	static, read-only board type information, i.e. the offset between each
409  *	pointer to a board name.
410  *
411  * This is used with comedi_driver_register() and comedi_driver_unregister() to
412  * register and unregister a low-level COMEDI driver with the COMEDI core.
413  *
414  * If @num_names is non-zero, @board_name should be non-NULL, and @offset
415  * should be at least sizeof(*board_name).  These are used by the handler for
416  * the %COMEDI_DEVCONFIG ioctl to match a hardware device and its driver by
417  * board name.  If @num_names is zero, the %COMEDI_DEVCONFIG ioctl matches a
418  * hardware device and its driver by driver name.  This is only useful if the
419  * @attach handler is set.  If @num_names is non-zero, the driver's @attach
420  * handler will be called with the COMEDI device structure's board_ptr member
421  * pointing to the matched pointer to a board name within the driver's private
422  * array of static, read-only board type information.
423  *
424  * The @detach handler has two roles.  If a COMEDI device was successfully
425  * configured by the @attach or @auto_attach handler, it is called when the
426  * device is being deconfigured (by the %COMEDI_DEVCONFIG ioctl, or due to
427  * unloading of the driver, or due to device removal).  It is also called when
428  * the @attach or @auto_attach handler returns an error.  Therefore, the
429  * @attach or @auto_attach handlers can defer clean-up on error until the
430  * @detach handler is called.  If the @attach or @auto_attach handlers free
431  * any resources themselves, they must prevent the @detach handler from
432  * freeing the same resources.  The @detach handler must not assume that all
433  * resources requested by the @attach or @auto_attach handler were
434  * successfully allocated.
435  */
436 struct comedi_driver {
437 	/* private: */
438 	struct comedi_driver *next;	/* Next in list of COMEDI drivers. */
439 	/* public: */
440 	const char *driver_name;
441 	struct module *module;
442 	int (*attach)(struct comedi_device *dev, struct comedi_devconfig *it);
443 	void (*detach)(struct comedi_device *dev);
444 	int (*auto_attach)(struct comedi_device *dev, unsigned long context);
445 	unsigned int num_names;
446 	const char *const *board_name;
447 	int offset;
448 };
449 
450 /**
451  * struct comedi_device - Working data for a COMEDI device
452  * @use_count: Number of open file objects.
453  * @driver: Low-level COMEDI driver attached to this COMEDI device.
454  * @pacer: Optional pointer to a dynamically allocated acquisition pacer
455  *	control.  It is freed automatically after the COMEDI device is
456  *	detached from the low-level driver.
457  * @private: Optional pointer to private data allocated by the low-level
458  *	driver.  It is freed automatically after the COMEDI device is
459  *	detached from the low-level driver.
460  * @class_dev: Sysfs comediX device.
461  * @minor: Minor device number of COMEDI char device (0-47).
462  * @detach_count: Counter incremented every time the COMEDI device is detached.
463  *	Used for checking a previous attachment is still valid.
464  * @hw_dev: Optional pointer to the low-level hardware &struct device.  It is
465  *	required for automatically configured COMEDI devices and optional for
466  *	COMEDI devices configured by the %COMEDI_DEVCONFIG ioctl, although
467  *	the bus-specific COMEDI functions only work if it is set correctly.
468  *	It is also passed to dma_alloc_coherent() for COMEDI subdevices that
469  *	have their 'async_dma_dir' member set to something other than
470  *	%DMA_NONE.
471  * @board_name: Pointer to a COMEDI board name or a COMEDI driver name.  When
472  *	the low-level driver's "attach" handler is called by the handler for
473  *	the %COMEDI_DEVCONFIG ioctl, it either points to a matched board name
474  *	string if the 'num_names' member of the &struct comedi_driver is
475  *	non-zero, otherwise it points to the low-level driver name string.
476  *	When the low-lever driver's "auto_attach" handler is called for an
477  *	automatically configured COMEDI device, it points to the low-level
478  *	driver name string.  The low-level driver is free to change it in its
479  *	"attach" or "auto_attach" handler if it wishes.
480  * @board_ptr: Optional pointer to private, read-only board type information in
481  *	the low-level driver.  If the 'num_names' member of the &struct
482  *	comedi_driver is non-zero, the handler for the %COMEDI_DEVCONFIG ioctl
483  *	will point it to a pointer to a matched board name string within the
484  *	driver's private array of static, read-only board type information when
485  *	calling the driver's "attach" handler.  The low-level driver is free to
486  *	change it.
487  * @attached: Flag indicating that the COMEDI device is attached to a low-level
488  *	driver.
489  * @ioenabled: Flag used to indicate that a PCI device has been enabled and
490  *	its regions requested.
491  * @spinlock: Generic spin-lock for use by the low-level driver.
492  * @mutex: Generic mutex for use by the COMEDI core module.
493  * @attach_lock: &struct rw_semaphore used to guard against the COMEDI device
494  *	being detached while an operation is in progress.  The down_write()
495  *	operation is only allowed while @mutex is held and is used when
496  *	changing @attached and @detach_count and calling the low-level driver's
497  *	"detach" handler.  The down_read() operation is generally used without
498  *	holding @mutex.
499  * @refcount: &struct kref reference counter for freeing COMEDI device.
500  * @n_subdevices: Number of COMEDI subdevices allocated by the low-level
501  *	driver for this device.
502  * @subdevices: Dynamically allocated array of COMEDI subdevices.
503  * @mmio: Optional pointer to a remapped MMIO region set by the low-level
504  *	driver.
505  * @iobase: Optional base of an I/O port region requested by the low-level
506  *	driver.
507  * @iolen: Length of I/O port region requested at @iobase.
508  * @irq: Optional IRQ number requested by the low-level driver.
509  * @read_subdev: Optional pointer to a default COMEDI subdevice operated on by
510  *	the read() file operation.  Set by the low-level driver.
511  * @write_subdev: Optional pointer to a default COMEDI subdevice operated on by
512  *	the write() file operation.  Set by the low-level driver.
513  * @async_queue: Storage for fasync_helper().
514  * @open: Optional pointer to a function set by the low-level driver to be
515  *	called when @use_count changes from 0 to 1.
516  * @close: Optional pointer to a function set by the low-level driver to be
517  *	called when @use_count changed from 1 to 0.
518  * @insn_device_config: Optional pointer to a handler for all sub-instructions
519  *	except %INSN_DEVICE_CONFIG_GET_ROUTES of the %INSN_DEVICE_CONFIG
520  *	instruction.  If this is not initialized by the low-level driver, a
521  *	default handler will be set during post-configuration.
522  * @get_valid_routes: Optional pointer to a handler for the
523  *	%INSN_DEVICE_CONFIG_GET_ROUTES sub-instruction of the
524  *	%INSN_DEVICE_CONFIG instruction set.  If this is not initialized by the
525  *	low-level driver, a default handler that copies zero routes back to the
526  *	user will be used.
527  *
528  * This is the main control data structure for a COMEDI device (as far as the
529  * COMEDI core is concerned).  There are two groups of COMEDI devices -
530  * "legacy" devices that are configured by the handler for the
531  * %COMEDI_DEVCONFIG ioctl, and automatically configured devices resulting
532  * from a call to comedi_auto_config() as a result of a bus driver probe in
533  * a low-level COMEDI driver.  The "legacy" COMEDI devices are allocated
534  * during module initialization if the "comedi_num_legacy_minors" module
535  * parameter is non-zero and use minor device numbers from 0 to
536  * comedi_num_legacy_minors minus one.  The automatically configured COMEDI
537  * devices are allocated on demand and use minor device numbers from
538  * comedi_num_legacy_minors to 47.
539  */
540 struct comedi_device {
541 	int use_count;
542 	struct comedi_driver *driver;
543 	struct comedi_8254 *pacer;
544 	void *private;
545 
546 	struct device *class_dev;
547 	int minor;
548 	unsigned int detach_count;
549 	struct device *hw_dev;
550 
551 	const char *board_name;
552 	const void *board_ptr;
553 	unsigned int attached:1;
554 	unsigned int ioenabled:1;
555 	spinlock_t spinlock;	/* generic spin-lock for low-level driver */
556 	struct mutex mutex;	/* generic mutex for COMEDI core */
557 	struct rw_semaphore attach_lock;
558 	struct kref refcount;
559 
560 	int n_subdevices;
561 	struct comedi_subdevice *subdevices;
562 
563 	/* dumb */
564 	void __iomem *mmio;
565 	unsigned long iobase;
566 	unsigned long iolen;
567 	unsigned int irq;
568 
569 	struct comedi_subdevice *read_subdev;
570 	struct comedi_subdevice *write_subdev;
571 
572 	struct fasync_struct *async_queue;
573 
574 	int (*open)(struct comedi_device *dev);
575 	void (*close)(struct comedi_device *dev);
576 	int (*insn_device_config)(struct comedi_device *dev,
577 				  struct comedi_insn *insn, unsigned int *data);
578 	unsigned int (*get_valid_routes)(struct comedi_device *dev,
579 					 unsigned int n_pairs,
580 					 unsigned int *pair_data);
581 };
582 
583 /*
584  * function prototypes
585  */
586 
587 void comedi_event(struct comedi_device *dev, struct comedi_subdevice *s);
588 
589 struct comedi_device *comedi_dev_get_from_minor(unsigned int minor);
590 int comedi_dev_put(struct comedi_device *dev);
591 
592 bool comedi_is_subdevice_running(struct comedi_subdevice *s);
593 
594 void *comedi_alloc_spriv(struct comedi_subdevice *s, size_t size);
595 void comedi_set_spriv_auto_free(struct comedi_subdevice *s);
596 
597 int comedi_check_chanlist(struct comedi_subdevice *s,
598 			  int n,
599 			  unsigned int *chanlist);
600 
601 /* range stuff */
602 
603 #define RANGE(a, b)		{(a) * 1e6, (b) * 1e6, 0}
604 #define RANGE_ext(a, b)		{(a) * 1e6, (b) * 1e6, RF_EXTERNAL}
605 #define RANGE_mA(a, b)		{(a) * 1e6, (b) * 1e6, UNIT_mA}
606 #define RANGE_unitless(a, b)	{(a) * 1e6, (b) * 1e6, 0}
607 #define BIP_RANGE(a)		{-(a) * 1e6, (a) * 1e6, 0}
608 #define UNI_RANGE(a)		{0, (a) * 1e6, 0}
609 
610 extern const struct comedi_lrange range_bipolar10;
611 extern const struct comedi_lrange range_bipolar5;
612 extern const struct comedi_lrange range_bipolar2_5;
613 extern const struct comedi_lrange range_unipolar10;
614 extern const struct comedi_lrange range_unipolar5;
615 extern const struct comedi_lrange range_unipolar2_5;
616 extern const struct comedi_lrange range_0_20mA;
617 extern const struct comedi_lrange range_4_20mA;
618 extern const struct comedi_lrange range_0_32mA;
619 extern const struct comedi_lrange range_unknown;
620 
621 #define range_digital		range_unipolar5
622 
623 /**
624  * struct comedi_lrange - Describes a COMEDI range table
625  * @length: Number of entries in the range table.
626  * @range: Array of &struct comedi_krange, one for each range.
627  *
628  * Each element of @range[] describes the minimum and maximum physical range
629  * and the type of units.  Typically, the type of unit is %UNIT_volt
630  * (i.e. volts) and the minimum and maximum are in millionths of a volt.
631  * There may also be a flag that indicates the minimum and maximum are merely
632  * scale factors for an unknown, external reference.
633  */
634 struct comedi_lrange {
635 	int length;
636 	struct comedi_krange range[];
637 };
638 
639 /**
640  * comedi_range_is_bipolar() - Test if subdevice range is bipolar
641  * @s: COMEDI subdevice.
642  * @range: Index of range within a range table.
643  *
644  * Tests whether a range is bipolar by checking whether its minimum value
645  * is negative.
646  *
647  * Assumes @range is valid.  Does not work for subdevices using a
648  * channel-specific range table list.
649  *
650  * Return:
651  *	%true if the range is bipolar.
652  *	%false if the range is unipolar.
653  */
comedi_range_is_bipolar(struct comedi_subdevice * s,unsigned int range)654 static inline bool comedi_range_is_bipolar(struct comedi_subdevice *s,
655 					   unsigned int range)
656 {
657 	return s->range_table->range[range].min < 0;
658 }
659 
660 /**
661  * comedi_range_is_unipolar() - Test if subdevice range is unipolar
662  * @s: COMEDI subdevice.
663  * @range: Index of range within a range table.
664  *
665  * Tests whether a range is unipolar by checking whether its minimum value
666  * is at least 0.
667  *
668  * Assumes @range is valid.  Does not work for subdevices using a
669  * channel-specific range table list.
670  *
671  * Return:
672  *	%true if the range is unipolar.
673  *	%false if the range is bipolar.
674  */
comedi_range_is_unipolar(struct comedi_subdevice * s,unsigned int range)675 static inline bool comedi_range_is_unipolar(struct comedi_subdevice *s,
676 					    unsigned int range)
677 {
678 	return s->range_table->range[range].min >= 0;
679 }
680 
681 /**
682  * comedi_range_is_external() - Test if subdevice range is external
683  * @s: COMEDI subdevice.
684  * @range: Index of range within a range table.
685  *
686  * Tests whether a range is externally reference by checking whether its
687  * %RF_EXTERNAL flag is set.
688  *
689  * Assumes @range is valid.  Does not work for subdevices using a
690  * channel-specific range table list.
691  *
692  * Return:
693  *	%true if the range is external.
694  *	%false if the range is internal.
695  */
comedi_range_is_external(struct comedi_subdevice * s,unsigned int range)696 static inline bool comedi_range_is_external(struct comedi_subdevice *s,
697 					    unsigned int range)
698 {
699 	return !!(s->range_table->range[range].flags & RF_EXTERNAL);
700 }
701 
702 /**
703  * comedi_chan_range_is_bipolar() - Test if channel-specific range is bipolar
704  * @s: COMEDI subdevice.
705  * @chan: The channel number.
706  * @range: Index of range within a range table.
707  *
708  * Tests whether a range is bipolar by checking whether its minimum value
709  * is negative.
710  *
711  * Assumes @chan and @range are valid.  Only works for subdevices with a
712  * channel-specific range table list.
713  *
714  * Return:
715  *	%true if the range is bipolar.
716  *	%false if the range is unipolar.
717  */
comedi_chan_range_is_bipolar(struct comedi_subdevice * s,unsigned int chan,unsigned int range)718 static inline bool comedi_chan_range_is_bipolar(struct comedi_subdevice *s,
719 						unsigned int chan,
720 						unsigned int range)
721 {
722 	return s->range_table_list[chan]->range[range].min < 0;
723 }
724 
725 /**
726  * comedi_chan_range_is_unipolar() - Test if channel-specific range is unipolar
727  * @s: COMEDI subdevice.
728  * @chan: The channel number.
729  * @range: Index of range within a range table.
730  *
731  * Tests whether a range is unipolar by checking whether its minimum value
732  * is at least 0.
733  *
734  * Assumes @chan and @range are valid.  Only works for subdevices with a
735  * channel-specific range table list.
736  *
737  * Return:
738  *	%true if the range is unipolar.
739  *	%false if the range is bipolar.
740  */
comedi_chan_range_is_unipolar(struct comedi_subdevice * s,unsigned int chan,unsigned int range)741 static inline bool comedi_chan_range_is_unipolar(struct comedi_subdevice *s,
742 						 unsigned int chan,
743 						 unsigned int range)
744 {
745 	return s->range_table_list[chan]->range[range].min >= 0;
746 }
747 
748 /**
749  * comedi_chan_range_is_external() - Test if channel-specific range is external
750  * @s: COMEDI subdevice.
751  * @chan: The channel number.
752  * @range: Index of range within a range table.
753  *
754  * Tests whether a range is externally reference by checking whether its
755  * %RF_EXTERNAL flag is set.
756  *
757  * Assumes @chan and @range are valid.  Only works for subdevices with a
758  * channel-specific range table list.
759  *
760  * Return:
761  *	%true if the range is bipolar.
762  *	%false if the range is unipolar.
763  */
comedi_chan_range_is_external(struct comedi_subdevice * s,unsigned int chan,unsigned int range)764 static inline bool comedi_chan_range_is_external(struct comedi_subdevice *s,
765 						 unsigned int chan,
766 						 unsigned int range)
767 {
768 	return !!(s->range_table_list[chan]->range[range].flags & RF_EXTERNAL);
769 }
770 
771 /**
772  * comedi_offset_munge() - Convert between offset binary and 2's complement
773  * @s: COMEDI subdevice.
774  * @val: Value to be converted.
775  *
776  * Toggles the highest bit of a sample value to toggle between offset binary
777  * and 2's complement.  Assumes that @s->maxdata is a power of 2 minus 1.
778  *
779  * Return: The converted value.
780  */
comedi_offset_munge(struct comedi_subdevice * s,unsigned int val)781 static inline unsigned int comedi_offset_munge(struct comedi_subdevice *s,
782 					       unsigned int val)
783 {
784 	return val ^ s->maxdata ^ (s->maxdata >> 1);
785 }
786 
787 /**
788  * comedi_bytes_per_sample() - Determine subdevice sample size
789  * @s: COMEDI subdevice.
790  *
791  * The sample size will be 4 (sizeof int) or 2 (sizeof short) depending on
792  * whether the %SDF_LSAMPL subdevice flag is set or not.
793  *
794  * Return: The subdevice sample size.
795  */
comedi_bytes_per_sample(struct comedi_subdevice * s)796 static inline unsigned int comedi_bytes_per_sample(struct comedi_subdevice *s)
797 {
798 	return s->subdev_flags & SDF_LSAMPL ? sizeof(int) : sizeof(short);
799 }
800 
801 /**
802  * comedi_sample_shift() - Determine log2 of subdevice sample size
803  * @s: COMEDI subdevice.
804  *
805  * The sample size will be 4 (sizeof int) or 2 (sizeof short) depending on
806  * whether the %SDF_LSAMPL subdevice flag is set or not.  The log2 of the
807  * sample size will be 2 or 1 and can be used as the right operand of a
808  * bit-shift operator to multiply or divide something by the sample size.
809  *
810  * Return: log2 of the subdevice sample size.
811  */
comedi_sample_shift(struct comedi_subdevice * s)812 static inline unsigned int comedi_sample_shift(struct comedi_subdevice *s)
813 {
814 	return s->subdev_flags & SDF_LSAMPL ? 2 : 1;
815 }
816 
817 /**
818  * comedi_bytes_to_samples() - Convert a number of bytes to a number of samples
819  * @s: COMEDI subdevice.
820  * @nbytes: Number of bytes
821  *
822  * Return: The number of bytes divided by the subdevice sample size.
823  */
comedi_bytes_to_samples(struct comedi_subdevice * s,unsigned int nbytes)824 static inline unsigned int comedi_bytes_to_samples(struct comedi_subdevice *s,
825 						   unsigned int nbytes)
826 {
827 	return nbytes >> comedi_sample_shift(s);
828 }
829 
830 /**
831  * comedi_samples_to_bytes() - Convert a number of samples to a number of bytes
832  * @s: COMEDI subdevice.
833  * @nsamples: Number of samples.
834  *
835  * Return: The number of samples multiplied by the subdevice sample size.
836  * (Does not check for arithmetic overflow.)
837  */
comedi_samples_to_bytes(struct comedi_subdevice * s,unsigned int nsamples)838 static inline unsigned int comedi_samples_to_bytes(struct comedi_subdevice *s,
839 						   unsigned int nsamples)
840 {
841 	return nsamples << comedi_sample_shift(s);
842 }
843 
844 /**
845  * comedi_check_trigger_src() - Trivially validate a comedi_cmd trigger source
846  * @src: Pointer to the trigger source to validate.
847  * @flags: Bitmask of valid %TRIG_* for the trigger.
848  *
849  * This is used in "step 1" of the do_cmdtest functions of comedi drivers
850  * to validate the comedi_cmd triggers. The mask of the @src against the
851  * @flags allows the userspace comedilib to pass all the comedi_cmd
852  * triggers as %TRIG_ANY and get back a bitmask of the valid trigger sources.
853  *
854  * Return:
855  *	0 if trigger sources in *@src are all supported.
856  *	-EINVAL if any trigger source in *@src is unsupported.
857  */
comedi_check_trigger_src(unsigned int * src,unsigned int flags)858 static inline int comedi_check_trigger_src(unsigned int *src,
859 					   unsigned int flags)
860 {
861 	unsigned int orig_src = *src;
862 
863 	*src = orig_src & flags;
864 	if (*src == TRIG_INVALID || *src != orig_src)
865 		return -EINVAL;
866 	return 0;
867 }
868 
869 /**
870  * comedi_check_trigger_is_unique() - Make sure a trigger source is unique
871  * @src: The trigger source to check.
872  *
873  * Return:
874  *	0 if no more than one trigger source is set.
875  *	-EINVAL if more than one trigger source is set.
876  */
comedi_check_trigger_is_unique(unsigned int src)877 static inline int comedi_check_trigger_is_unique(unsigned int src)
878 {
879 	/* this test is true if more than one _src bit is set */
880 	if ((src & (src - 1)) != 0)
881 		return -EINVAL;
882 	return 0;
883 }
884 
885 /**
886  * comedi_check_trigger_arg_is() - Trivially validate a trigger argument
887  * @arg: Pointer to the trigger arg to validate.
888  * @val: The value the argument should be.
889  *
890  * Forces *@arg to be @val.
891  *
892  * Return:
893  *	0 if *@arg was already @val.
894  *	-EINVAL if *@arg differed from @val.
895  */
comedi_check_trigger_arg_is(unsigned int * arg,unsigned int val)896 static inline int comedi_check_trigger_arg_is(unsigned int *arg,
897 					      unsigned int val)
898 {
899 	if (*arg != val) {
900 		*arg = val;
901 		return -EINVAL;
902 	}
903 	return 0;
904 }
905 
906 /**
907  * comedi_check_trigger_arg_min() - Trivially validate a trigger argument min
908  * @arg: Pointer to the trigger arg to validate.
909  * @val: The minimum value the argument should be.
910  *
911  * Forces *@arg to be at least @val, setting it to @val if necessary.
912  *
913  * Return:
914  *	0 if *@arg was already at least @val.
915  *	-EINVAL if *@arg was less than @val.
916  */
comedi_check_trigger_arg_min(unsigned int * arg,unsigned int val)917 static inline int comedi_check_trigger_arg_min(unsigned int *arg,
918 					       unsigned int val)
919 {
920 	if (*arg < val) {
921 		*arg = val;
922 		return -EINVAL;
923 	}
924 	return 0;
925 }
926 
927 /**
928  * comedi_check_trigger_arg_max() - Trivially validate a trigger argument max
929  * @arg: Pointer to the trigger arg to validate.
930  * @val: The maximum value the argument should be.
931  *
932  * Forces *@arg to be no more than @val, setting it to @val if necessary.
933  *
934  * Return:
935  *	0 if*@arg was already no more than @val.
936  *	-EINVAL if *@arg was greater than @val.
937  */
comedi_check_trigger_arg_max(unsigned int * arg,unsigned int val)938 static inline int comedi_check_trigger_arg_max(unsigned int *arg,
939 					       unsigned int val)
940 {
941 	if (*arg > val) {
942 		*arg = val;
943 		return -EINVAL;
944 	}
945 	return 0;
946 }
947 
948 /*
949  * Must set dev->hw_dev if you wish to dma directly into comedi's buffer.
950  * Also useful for retrieving a previously configured hardware device of
951  * known bus type.  Set automatically for auto-configured devices.
952  * Automatically set to NULL when detaching hardware device.
953  */
954 int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev);
955 
956 /**
957  * comedi_buf_n_bytes_ready - Determine amount of unread data in buffer
958  * @s: COMEDI subdevice.
959  *
960  * Determines the number of bytes of unread data in the asynchronous
961  * acquisition data buffer for a subdevice.  The data in question might not
962  * have been fully "munged" yet.
963  *
964  * Returns: The amount of unread data in bytes.
965  */
comedi_buf_n_bytes_ready(struct comedi_subdevice * s)966 static inline unsigned int comedi_buf_n_bytes_ready(struct comedi_subdevice *s)
967 {
968 	return s->async->buf_write_count - s->async->buf_read_count;
969 }
970 
971 unsigned int comedi_buf_write_alloc(struct comedi_subdevice *s, unsigned int n);
972 unsigned int comedi_buf_write_free(struct comedi_subdevice *s, unsigned int n);
973 
974 unsigned int comedi_buf_read_n_available(struct comedi_subdevice *s);
975 unsigned int comedi_buf_read_alloc(struct comedi_subdevice *s, unsigned int n);
976 unsigned int comedi_buf_read_free(struct comedi_subdevice *s, unsigned int n);
977 
978 unsigned int comedi_buf_write_samples(struct comedi_subdevice *s,
979 				      const void *data, unsigned int nsamples);
980 unsigned int comedi_buf_read_samples(struct comedi_subdevice *s,
981 				     void *data, unsigned int nsamples);
982 
983 /* drivers.c - general comedi driver functions */
984 
985 #define COMEDI_TIMEOUT_MS	1000
986 
987 int comedi_timeout(struct comedi_device *dev, struct comedi_subdevice *s,
988 		   struct comedi_insn *insn,
989 		   int (*cb)(struct comedi_device *dev,
990 			     struct comedi_subdevice *s,
991 			     struct comedi_insn *insn, unsigned long context),
992 		   unsigned long context);
993 
994 unsigned int comedi_handle_events(struct comedi_device *dev,
995 				  struct comedi_subdevice *s);
996 
997 int comedi_dio_insn_config(struct comedi_device *dev,
998 			   struct comedi_subdevice *s,
999 			   struct comedi_insn *insn, unsigned int *data,
1000 			   unsigned int mask);
1001 unsigned int comedi_dio_update_state(struct comedi_subdevice *s,
1002 				     unsigned int *data);
1003 unsigned int comedi_bytes_per_scan_cmd(struct comedi_subdevice *s,
1004 				       struct comedi_cmd *cmd);
1005 unsigned int comedi_bytes_per_scan(struct comedi_subdevice *s);
1006 unsigned int comedi_nscans_left(struct comedi_subdevice *s,
1007 				unsigned int nscans);
1008 unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
1009 				  unsigned int nsamples);
1010 void comedi_inc_scan_progress(struct comedi_subdevice *s,
1011 			      unsigned int num_bytes);
1012 
1013 void *comedi_alloc_devpriv(struct comedi_device *dev, size_t size);
1014 int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices);
1015 int comedi_alloc_subdev_readback(struct comedi_subdevice *s);
1016 
1017 int comedi_readback_insn_read(struct comedi_device *dev,
1018 			      struct comedi_subdevice *s,
1019 			      struct comedi_insn *insn, unsigned int *data);
1020 
1021 int comedi_load_firmware(struct comedi_device *dev, struct device *hw_dev,
1022 			 const char *name,
1023 			 int (*cb)(struct comedi_device *dev,
1024 				   const u8 *data, size_t size,
1025 				   unsigned long context),
1026 			 unsigned long context);
1027 
1028 int __comedi_request_region(struct comedi_device *dev,
1029 			    unsigned long start, unsigned long len);
1030 int comedi_request_region(struct comedi_device *dev,
1031 			  unsigned long start, unsigned long len);
1032 void comedi_legacy_detach(struct comedi_device *dev);
1033 
1034 int comedi_auto_config(struct device *hardware_device,
1035 		       struct comedi_driver *driver, unsigned long context);
1036 void comedi_auto_unconfig(struct device *hardware_device);
1037 
1038 int comedi_driver_register(struct comedi_driver *driver);
1039 void comedi_driver_unregister(struct comedi_driver *driver);
1040 
1041 /**
1042  * module_comedi_driver() - Helper macro for registering a comedi driver
1043  * @__comedi_driver: comedi_driver struct
1044  *
1045  * Helper macro for comedi drivers which do not do anything special in module
1046  * init/exit. This eliminates a lot of boilerplate. Each module may only use
1047  * this macro once, and calling it replaces module_init() and module_exit().
1048  */
1049 #define module_comedi_driver(__comedi_driver) \
1050 	module_driver(__comedi_driver, comedi_driver_register, \
1051 			comedi_driver_unregister)
1052 
1053 #endif /* _COMEDIDEV_H */
1054