/*
    include/linux/comedidev.h
    header file for kernel-only structures, variables, and constants

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
*/

#ifndef _COMEDIDEV_H
#define _COMEDIDEV_H

#include <linux/dma-mapping.h>
#include <linux/mutex.h>
#include <linux/spinlock_types.h>
#include <linux/rwsem.h>
#include <linux/kref.h>

#include "comedi.h"

#define COMEDI_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + (c))
#define COMEDI_VERSION_CODE COMEDI_VERSION(COMEDI_MAJORVERSION, \
	COMEDI_MINORVERSION, COMEDI_MICROVERSION)
#define COMEDI_RELEASE VERSION

#define COMEDI_NUM_BOARD_MINORS 0x30

struct comedi_subdevice {
	struct comedi_device *device;
	int index;
	int type;
	int n_chan;
	int subdev_flags;
	int len_chanlist;	/* maximum length of channel/gain list */

	void *private;

	struct comedi_async *async;

	void *lock;
	void *busy;
	unsigned runflags;
	spinlock_t spin_lock;

	unsigned int io_bits;

	unsigned int maxdata;	/* if maxdata==0, use list */
	const unsigned int *maxdata_list;	/* list is channel specific */

	const struct comedi_lrange *range_table;
	const struct comedi_lrange *const *range_table_list;

	unsigned int *chanlist;	/* driver-owned chanlist (not used) */

	int (*insn_read)(struct comedi_device *, struct comedi_subdevice *,
			 struct comedi_insn *, unsigned int *);
	int (*insn_write)(struct comedi_device *, struct comedi_subdevice *,
			  struct comedi_insn *, unsigned int *);
	int (*insn_bits)(struct comedi_device *, struct comedi_subdevice *,
			 struct comedi_insn *, unsigned int *);
	int (*insn_config)(struct comedi_device *, struct comedi_subdevice *,
			   struct comedi_insn *, unsigned int *);

	int (*do_cmd)(struct comedi_device *, struct comedi_subdevice *);
	int (*do_cmdtest)(struct comedi_device *, struct comedi_subdevice *,
			  struct comedi_cmd *);
	int (*poll)(struct comedi_device *, struct comedi_subdevice *);
	int (*cancel)(struct comedi_device *, struct comedi_subdevice *);

	/* called when the buffer changes */
	int (*buf_change)(struct comedi_device *, struct comedi_subdevice *);

	void (*munge)(struct comedi_device *dev, struct comedi_subdevice *s,
		      void *data, unsigned int num_bytes,
		      unsigned int start_chan_index);
	enum dma_data_direction async_dma_dir;

	unsigned int state;

	struct device *class_dev;
	int minor;

	unsigned int *readback;
};

struct comedi_buf_page {
	void *virt_addr;
	dma_addr_t dma_addr;
};

struct comedi_buf_map {
	struct device *dma_hw_dev;
	struct comedi_buf_page *page_list;
	unsigned int n_pages;
	enum dma_data_direction dma_dir;
	struct kref refcount;
};

/**
 * struct comedi_async - control data for asynchronous comedi commands
 * @prealloc_buf:	preallocated buffer
 * @prealloc_bufsz:	buffer size (in bytes)
 * @buf_map:		map of buffer pages
 * @max_bufsize:	maximum buffer size (in bytes)
 * @buf_write_count:	"write completed" count (in bytes, modulo 2**32)
 * @buf_write_alloc_count: "allocated for writing" count (in bytes,
 *			modulo 2**32)
 * @buf_read_count:	"read completed" count (in bytes, modulo 2**32)
 * @buf_read_alloc_count: "allocated for reading" count (in bytes,
 *			modulo 2**32)
 * @buf_write_ptr:	buffer position for writer
 * @buf_read_ptr:	buffer position for reader
 * @cur_chan:		current position in chanlist for scan (for those
 *			drivers that use it)
 * @scans_done:		the number of scans completed (COMEDI_CB_EOS)
 * @scan_progress:	amount received or sent for current scan (in bytes)
 * @munge_chan:		current position in chanlist for "munging"
 * @munge_count:	"munge" count (in bytes, modulo 2**32)
 * @munge_ptr:		buffer position for "munging"
 * @events:		bit-vector of events that have occurred
 * @cmd:		details of comedi command in progress
 * @wait_head:		task wait queue for file reader or writer
 * @cb_mask:		bit-vector of events that should wake waiting tasks
 * @inttrig:		software trigger function for command, or NULL
 *
 * Note about the ..._count and ..._ptr members:
 *
 * Think of the _Count values being integers of unlimited size, indexing
 * into a buffer of infinite length (though only an advancing portion
 * of the buffer of fixed length prealloc_bufsz is accessible at any time).
 * Then:
 *
 *   Buf_Read_Count <= Buf_Read_Alloc_Count <= Munge_Count <=
 *   Buf_Write_Count <= Buf_Write_Alloc_Count <=
 *   (Buf_Read_Count + prealloc_bufsz)
 *
 * (Those aren't the actual members, apart from prealloc_bufsz.) When
 * the buffer is reset, those _Count values start at 0 and only increase
 * in value, maintaining the above inequalities until the next time the
 * buffer is reset.  The buffer is divided into the following regions by
 * the inequalities:
 *
 *   [0, Buf_Read_Count):
 *     old region no longer accessible
 *   [Buf_Read_Count, Buf_Read_Alloc_Count):
 *     filled and munged region allocated for reading but not yet read
 *   [Buf_Read_Alloc_Count, Munge_Count):
 *     filled and munged region not yet allocated for reading
 *   [Munge_Count, Buf_Write_Count):
 *     filled region not yet munged
 *   [Buf_Write_Count, Buf_Write_Alloc_Count):
 *     unfilled region allocated for writing but not yet written
 *   [Buf_Write_Alloc_Count, Buf_Read_Count + prealloc_bufsz):
 *     unfilled region not yet allocated for writing
 *   [Buf_Read_Count + prealloc_bufsz, infinity):
 *     unfilled region not yet accessible
 *
 * Data needs to be written into the buffer before it can be read out,
 * and may need to be converted (or "munged") between the two
 * operations.  Extra unfilled buffer space may need to allocated for
 * writing (advancing Buf_Write_Alloc_Count) before new data is written.
 * After writing new data, the newly filled space needs to be released
 * (advancing Buf_Write_Count).  This also results in the new data being
 * "munged" (advancing Munge_Count).  Before data is read out of the
 * buffer, extra space may need to be allocated for reading (advancing
 * Buf_Read_Alloc_Count).  After the data has been read out, the space
 * needs to be released (advancing Buf_Read_Count).
 *
 * The actual members, buf_read_count, buf_read_alloc_count,
 * munge_count, buf_write_count, and buf_write_alloc_count take the
 * value of the corresponding capitalized _Count values modulo 2^32
 * (UINT_MAX+1).  Subtracting a "higher" _count value from a "lower"
 * _count value gives the same answer as subtracting a "higher" _Count
 * value from a lower _Count value because prealloc_bufsz < UINT_MAX+1.
 * The modulo operation is done implicitly.
 *
 * The buf_read_ptr, munge_ptr, and buf_write_ptr members take the value
 * of the corresponding capitalized _Count values modulo prealloc_bufsz.
 * These correspond to byte indices in the physical buffer.  The modulo
 * operation is done by subtracting prealloc_bufsz when the value
 * exceeds prealloc_bufsz (assuming prealloc_bufsz plus the increment is
 * less than or equal to UINT_MAX).
 */
struct comedi_async {
	void *prealloc_buf;
	unsigned int prealloc_bufsz;
	struct comedi_buf_map *buf_map;
	unsigned int max_bufsize;
	unsigned int buf_write_count;
	unsigned int buf_write_alloc_count;
	unsigned int buf_read_count;
	unsigned int buf_read_alloc_count;
	unsigned int buf_write_ptr;
	unsigned int buf_read_ptr;
	unsigned int cur_chan;
	unsigned int scans_done;
	unsigned int scan_progress;
	unsigned int munge_chan;
	unsigned int munge_count;
	unsigned int munge_ptr;
	unsigned int events;
	struct comedi_cmd cmd;
	wait_queue_head_t wait_head;
	unsigned int cb_mask;
	int (*inttrig)(struct comedi_device *dev, struct comedi_subdevice *s,
		       unsigned int x);
};

/**
 * comedi_async callback "events"
 * @COMEDI_CB_EOS:		end-of-scan
 * @COMEDI_CB_EOA:		end-of-acquisition/output
 * @COMEDI_CB_BLOCK:		data has arrived, wakes up read() / write()
 * @COMEDI_CB_EOBUF:		DEPRECATED: end of buffer
 * @COMEDI_CB_ERROR:		card error during acquisition
 * @COMEDI_CB_OVERFLOW:		buffer overflow/underflow
 *
 * @COMEDI_CB_ERROR_MASK:	events that indicate an error has occurred
 * @COMEDI_CB_CANCEL_MASK:	events that will cancel an async command
 */
#define COMEDI_CB_EOS		BIT(0)
#define COMEDI_CB_EOA		BIT(1)
#define COMEDI_CB_BLOCK		BIT(2)
#define COMEDI_CB_EOBUF		BIT(3)
#define COMEDI_CB_ERROR		BIT(4)
#define COMEDI_CB_OVERFLOW	BIT(5)

#define COMEDI_CB_ERROR_MASK	(COMEDI_CB_ERROR | COMEDI_CB_OVERFLOW)
#define COMEDI_CB_CANCEL_MASK	(COMEDI_CB_EOA | COMEDI_CB_ERROR_MASK)

struct comedi_driver {
	struct comedi_driver *next;

	const char *driver_name;
	struct module *module;
	int (*attach)(struct comedi_device *, struct comedi_devconfig *);
	void (*detach)(struct comedi_device *);
	int (*auto_attach)(struct comedi_device *, unsigned long);

	/* number of elements in board_name and board_id arrays */
	unsigned int num_names;
	const char *const *board_name;
	/* offset in bytes from one board name pointer to the next */
	int offset;
};

struct comedi_device {
	int use_count;
	struct comedi_driver *driver;
	struct comedi_8254 *pacer;
	void *private;

	struct device *class_dev;
	int minor;
	unsigned int detach_count;
	/* hw_dev is passed to dma_alloc_coherent when allocating async buffers
	 * for subdevices that have async_dma_dir set to something other than
	 * DMA_NONE */
	struct device *hw_dev;

	const char *board_name;
	const void *board_ptr;
	bool attached:1;
	bool ioenabled:1;
	spinlock_t spinlock;
	struct mutex mutex;
	struct rw_semaphore attach_lock;
	struct kref refcount;

	int n_subdevices;
	struct comedi_subdevice *subdevices;

	/* dumb */
	void __iomem *mmio;
	unsigned long iobase;
	unsigned long iolen;
	unsigned int irq;

	struct comedi_subdevice *read_subdev;
	struct comedi_subdevice *write_subdev;

	struct fasync_struct *async_queue;

	int (*open)(struct comedi_device *dev);
	void (*close)(struct comedi_device *dev);
};

/*
 * function prototypes
 */

void comedi_event(struct comedi_device *dev, struct comedi_subdevice *s);

struct comedi_device *comedi_dev_get_from_minor(unsigned minor);
int comedi_dev_put(struct comedi_device *dev);

bool comedi_is_subdevice_running(struct comedi_subdevice *s);

void *comedi_alloc_spriv(struct comedi_subdevice *s, size_t size);
void comedi_set_spriv_auto_free(struct comedi_subdevice *s);

int comedi_check_chanlist(struct comedi_subdevice *s,
			  int n,
			  unsigned int *chanlist);

/* range stuff */

#define RANGE(a, b)		{(a)*1e6, (b)*1e6, 0}
#define RANGE_ext(a, b)		{(a)*1e6, (b)*1e6, RF_EXTERNAL}
#define RANGE_mA(a, b)		{(a)*1e6, (b)*1e6, UNIT_mA}
#define RANGE_unitless(a, b)	{(a)*1e6, (b)*1e6, 0}
#define BIP_RANGE(a)		{-(a)*1e6, (a)*1e6, 0}
#define UNI_RANGE(a)		{0, (a)*1e6, 0}

extern const struct comedi_lrange range_bipolar10;
extern const struct comedi_lrange range_bipolar5;
extern const struct comedi_lrange range_bipolar2_5;
extern const struct comedi_lrange range_unipolar10;
extern const struct comedi_lrange range_unipolar5;
extern const struct comedi_lrange range_unipolar2_5;
extern const struct comedi_lrange range_0_20mA;
extern const struct comedi_lrange range_4_20mA;
extern const struct comedi_lrange range_0_32mA;
extern const struct comedi_lrange range_unknown;

#define range_digital		range_unipolar5

#if __GNUC__ >= 3
#define GCC_ZERO_LENGTH_ARRAY
#else
#define GCC_ZERO_LENGTH_ARRAY 0
#endif

struct comedi_lrange {
	int length;
	struct comedi_krange range[GCC_ZERO_LENGTH_ARRAY];
};

static inline bool comedi_range_is_bipolar(struct comedi_subdevice *s,
					   unsigned int range)
{
	return s->range_table->range[range].min < 0;
}

static inline bool comedi_range_is_unipolar(struct comedi_subdevice *s,
					    unsigned int range)
{
	return s->range_table->range[range].min >= 0;
}

static inline bool comedi_range_is_external(struct comedi_subdevice *s,
					    unsigned int range)
{
	return !!(s->range_table->range[range].flags & RF_EXTERNAL);
}

static inline bool comedi_chan_range_is_bipolar(struct comedi_subdevice *s,
						unsigned int chan,
						unsigned int range)
{
	return s->range_table_list[chan]->range[range].min < 0;
}

static inline bool comedi_chan_range_is_unipolar(struct comedi_subdevice *s,
						 unsigned int chan,
						 unsigned int range)
{
	return s->range_table_list[chan]->range[range].min >= 0;
}

static inline bool comedi_chan_range_is_external(struct comedi_subdevice *s,
						 unsigned int chan,
						 unsigned int range)
{
	return !!(s->range_table_list[chan]->range[range].flags & RF_EXTERNAL);
}

/* munge between offset binary and two's complement values */
static inline unsigned int comedi_offset_munge(struct comedi_subdevice *s,
					       unsigned int val)
{
	return val ^ s->maxdata ^ (s->maxdata >> 1);
}

/**
 * comedi_bytes_per_sample - determine subdevice sample size
 * @s:		comedi_subdevice struct
 *
 * The sample size will be 4 (sizeof int) or 2 (sizeof short) depending on
 * whether the SDF_LSAMPL subdevice flag is set or not.
 *
 * Returns the subdevice sample size.
 */
static inline unsigned int comedi_bytes_per_sample(struct comedi_subdevice *s)
{
	return s->subdev_flags & SDF_LSAMPL ? sizeof(int) : sizeof(short);
}

/**
 * comedi_sample_shift - determine log2 of subdevice sample size
 * @s:		comedi_subdevice struct
 *
 * The sample size will be 4 (sizeof int) or 2 (sizeof short) depending on
 * whether the SDF_LSAMPL subdevice flag is set or not.  The log2 of the
 * sample size will be 2 or 1 and can be used as the right operand of a
 * bit-shift operator to multiply or divide something by the sample size.
 *
 * Returns log2 of the subdevice sample size.
 */
static inline unsigned int comedi_sample_shift(struct comedi_subdevice *s)
{
	return s->subdev_flags & SDF_LSAMPL ? 2 : 1;
}

/**
 * comedi_bytes_to_samples - converts a number of bytes to a number of samples
 * @s:		comedi_subdevice struct
 * @nbytes:	number of bytes
 *
 * Returns the number of bytes divided by the subdevice sample size.
 */
static inline unsigned int comedi_bytes_to_samples(struct comedi_subdevice *s,
						   unsigned int nbytes)
{
	return nbytes >> comedi_sample_shift(s);
}

/**
 * comedi_samples_to_bytes - converts a number of samples to a number of bytes
 * @s:		comedi_subdevice struct
 * @nsamples:	number of samples
 *
 * Returns the number of samples multiplied by the subdevice sample size.
 * Does not check for arithmetic overflow.
 */
static inline unsigned int comedi_samples_to_bytes(struct comedi_subdevice *s,
						   unsigned int nsamples)
{
	return nsamples << comedi_sample_shift(s);
}

/**
 * comedi_check_trigger_src() - trivially validate a comedi_cmd trigger source
 * @src: pointer to the trigger source to validate
 * @flags: bitmask of valid TRIG_* for the trigger
 *
 * This is used in "step 1" of the do_cmdtest functions of comedi drivers
 * to vaildate the comedi_cmd triggers. The mask of the @src against the
 * @flags allows the userspace comedilib to pass all the comedi_cmd
 * triggers as TRIG_ANY and get back a bitmask of the valid trigger sources.
 */
static inline int comedi_check_trigger_src(unsigned int *src,
					   unsigned int flags)
{
	unsigned int orig_src = *src;

	*src = orig_src & flags;
	if (*src == TRIG_INVALID || *src != orig_src)
		return -EINVAL;
	return 0;
}

/**
 * comedi_check_trigger_is_unique() - make sure a trigger source is unique
 * @src: the trigger source to check
 */
static inline int comedi_check_trigger_is_unique(unsigned int src)
{
	/* this test is true if more than one _src bit is set */
	if ((src & (src - 1)) != 0)
		return -EINVAL;
	return 0;
}

/**
 * comedi_check_trigger_arg_is() - trivially validate a trigger argument
 * @arg: pointer to the trigger arg to validate
 * @val: the value the argument should be
 */
static inline int comedi_check_trigger_arg_is(unsigned int *arg,
					      unsigned int val)
{
	if (*arg != val) {
		*arg = val;
		return -EINVAL;
	}
	return 0;
}

/**
 * comedi_check_trigger_arg_min() - trivially validate a trigger argument
 * @arg: pointer to the trigger arg to validate
 * @val: the minimum value the argument should be
 */
static inline int comedi_check_trigger_arg_min(unsigned int *arg,
					       unsigned int val)
{
	if (*arg < val) {
		*arg = val;
		return -EINVAL;
	}
	return 0;
}

/**
 * comedi_check_trigger_arg_max() - trivially validate a trigger argument
 * @arg: pointer to the trigger arg to validate
 * @val: the maximum value the argument should be
 */
static inline int comedi_check_trigger_arg_max(unsigned int *arg,
					       unsigned int val)
{
	if (*arg > val) {
		*arg = val;
		return -EINVAL;
	}
	return 0;
}

/*
 * Must set dev->hw_dev if you wish to dma directly into comedi's buffer.
 * Also useful for retrieving a previously configured hardware device of
 * known bus type.  Set automatically for auto-configured devices.
 * Automatically set to NULL when detaching hardware device.
 */
int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev);

static inline unsigned int comedi_buf_n_bytes_ready(struct comedi_subdevice *s)
{
	return s->async->buf_write_count - s->async->buf_read_count;
}

unsigned int comedi_buf_write_alloc(struct comedi_subdevice *s, unsigned int n);
unsigned int comedi_buf_write_free(struct comedi_subdevice *s, unsigned int n);

unsigned int comedi_buf_read_n_available(struct comedi_subdevice *s);
unsigned int comedi_buf_read_alloc(struct comedi_subdevice *s, unsigned int n);
unsigned int comedi_buf_read_free(struct comedi_subdevice *s, unsigned int n);

unsigned int comedi_buf_write_samples(struct comedi_subdevice *s,
				      const void *data, unsigned int nsamples);
unsigned int comedi_buf_read_samples(struct comedi_subdevice *s,
				     void *data, unsigned int nsamples);

/* drivers.c - general comedi driver functions */

#define COMEDI_TIMEOUT_MS	1000

int comedi_timeout(struct comedi_device *, struct comedi_subdevice *,
		   struct comedi_insn *,
		   int (*cb)(struct comedi_device *, struct comedi_subdevice *,
			     struct comedi_insn *, unsigned long context),
		   unsigned long context);

unsigned int comedi_handle_events(struct comedi_device *dev,
				  struct comedi_subdevice *s);

int comedi_dio_insn_config(struct comedi_device *, struct comedi_subdevice *,
			   struct comedi_insn *, unsigned int *data,
			   unsigned int mask);
unsigned int comedi_dio_update_state(struct comedi_subdevice *,
				     unsigned int *data);
unsigned int comedi_bytes_per_scan(struct comedi_subdevice *s);
unsigned int comedi_nscans_left(struct comedi_subdevice *s,
				unsigned int nscans);
unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
				  unsigned int nsamples);
void comedi_inc_scan_progress(struct comedi_subdevice *s,
			      unsigned int num_bytes);

void *comedi_alloc_devpriv(struct comedi_device *, size_t);
int comedi_alloc_subdevices(struct comedi_device *, int);
int comedi_alloc_subdev_readback(struct comedi_subdevice *);

int comedi_readback_insn_read(struct comedi_device *, struct comedi_subdevice *,
			      struct comedi_insn *, unsigned int *data);

int comedi_load_firmware(struct comedi_device *, struct device *,
			 const char *name,
			 int (*cb)(struct comedi_device *,
				   const u8 *data, size_t size,
				   unsigned long context),
			 unsigned long context);

int __comedi_request_region(struct comedi_device *,
			    unsigned long start, unsigned long len);
int comedi_request_region(struct comedi_device *,
			  unsigned long start, unsigned long len);
void comedi_legacy_detach(struct comedi_device *);

int comedi_auto_config(struct device *, struct comedi_driver *,
		       unsigned long context);
void comedi_auto_unconfig(struct device *);

int comedi_driver_register(struct comedi_driver *);
void comedi_driver_unregister(struct comedi_driver *);

/**
 * module_comedi_driver() - Helper macro for registering a comedi driver
 * @__comedi_driver: comedi_driver struct
 *
 * Helper macro for comedi drivers which do not do anything special in module
 * init/exit. This eliminates a lot of boilerplate. Each module may only use
 * this macro once, and calling it replaces module_init() and module_exit().
 */
#define module_comedi_driver(__comedi_driver) \
	module_driver(__comedi_driver, comedi_driver_register, \
			comedi_driver_unregister)

#endif /* _COMEDIDEV_H */