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/* The industrial I/O core - generic ring buffer interfaces.
*
* Copyright (c) 2008 Jonathan Cameron
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#ifndef _IIO_RING_GENERIC_H_
#define _IIO_RING_GENERIC_H_
#include "iio.h"
struct iio_handler;
struct iio_ring_buffer;
struct iio_dev;
/**
* iio_push_ring_event() - ring buffer specific push to event chrdev
* @ring_buf: ring buffer that is the event source
* @event_code: event indentification code
* @timestamp: time of event
**/
int iio_push_ring_event(struct iio_ring_buffer *ring_buf,
int event_code,
s64 timestamp);
/**
* iio_push_or_escallate_ring_event() - escalate or add as appropriate
* @ring_buf: ring buffer that is the event source
* @event_code: event indentification code
* @timestamp: time of event
*
* Typical usecase is to escalate a 50% ring full to 75% full if noone has yet
* read the first event. Clearly the 50% full is no longer of interest in
* typical use case.
**/
int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf,
int event_code,
s64 timestamp);
/**
* struct iio_ring_access_funcs - access functions for ring buffers.
* @mark_in_use: reference counting, typically to prevent module removal
* @unmark_in_use: reduce reference count when no longer using ring buffer
* @store_to: actually store stuff to the ring buffer
* @read_last: get the last element stored
* @rip_lots: try to get a specified number of elements (must exist)
* @mark_param_change: notify ring that some relevant parameter has changed
* Often this means the underlying storage may need to
* change.
* @request_update: if a parameter change has been marked, update underlying
* storage.
* @get_bpd: get current bytes per datum
* @set_bpd: set number of bytes per datum
* @get_length: get number of datums in ring
* @set_length: set number of datums in ring
* @is_enabled: query if ring is currently being used
* @enable: enable the ring
*
* The purpose of this structure is to make the ring buffer element
* modular as event for a given driver, different usecases may require
* different ring designs (space efficiency vs speed for example).
*
* It is worth noting that a given ring implementation may only support a small
* proportion of these functions. The core code 'should' cope fine with any of
* them not existing.
**/
struct iio_ring_access_funcs {
void (*mark_in_use)(struct iio_ring_buffer *ring);
void (*unmark_in_use)(struct iio_ring_buffer *ring);
int (*store_to)(struct iio_ring_buffer *ring, u8 *data, s64 timestamp);
int (*read_last)(struct iio_ring_buffer *ring, u8 *data);
int (*rip_lots)(struct iio_ring_buffer *ring,
size_t count,
u8 **data,
int *dead_offset);
int (*mark_param_change)(struct iio_ring_buffer *ring);
int (*request_update)(struct iio_ring_buffer *ring);
int (*get_bpd)(struct iio_ring_buffer *ring);
int (*set_bpd)(struct iio_ring_buffer *ring, size_t bpd);
int (*get_length)(struct iio_ring_buffer *ring);
int (*set_length)(struct iio_ring_buffer *ring, int length);
int (*is_enabled)(struct iio_ring_buffer *ring);
int (*enable)(struct iio_ring_buffer *ring);
};
/**
* struct iio_ring_buffer - general ring buffer structure
* @dev: ring buffer device struct
* @access_dev: system device struct for the chrdev
* @indio_dev: industrial I/O device structure
* @owner: module that owns the ring buffer (for ref counting)
* @id: unique id number
* @access_id: device id number
* @length: [DEVICE] number of datums in ring
* @bpd: [DEVICE] size of individual datum including timestamp
* @loopcount: [INTERN] number of times the ring has looped
* @access_handler: [INTERN] chrdev access handling
* @ev_int: [INTERN] chrdev interface for the event chrdev
* @shared_ev_pointer: [INTERN] the shared event pointer to allow escalation of
* events
* @access: [DRIVER] ring access functions associated with the
* implementation.
* @preenable: [DRIVER] function to run prior to marking ring enabled
* @postenable: [DRIVER] function to run after marking ring enabled
* @predisable: [DRIVER] function to run prior to marking ring disabled
* @postdisable: [DRIVER] function to run after marking ring disabled
**/
struct iio_ring_buffer {
struct device dev;
struct device access_dev;
struct iio_dev *indio_dev;
struct module *owner;
int id;
int access_id;
int length;
int bpd;
int loopcount;
struct iio_handler access_handler;
struct iio_event_interface ev_int;
struct iio_shared_ev_pointer shared_ev_pointer;
struct iio_ring_access_funcs access;
int (*preenable)(struct iio_dev *);
int (*postenable)(struct iio_dev *);
int (*predisable)(struct iio_dev *);
int (*postdisable)(struct iio_dev *);
};
void iio_ring_buffer_init(struct iio_ring_buffer *ring,
struct iio_dev *dev_info);
/**
* __iio_update_ring_buffer() - update common elements of ring buffers
* @ring: ring buffer that is the event source
* @bytes_per_datum: size of individual datum including timestamp
* @length: number of datums in ring
**/
static inline void __iio_update_ring_buffer(struct iio_ring_buffer *ring,
int bytes_per_datum, int length)
{
ring->bpd = bytes_per_datum;
ring->length = length;
ring->loopcount = 0;
}
/**
* struct iio_scan_el - an individual element of a scan
* @dev_attr: control attribute (if directly controllable)
* @number: unique identifier of element (used for bit mask)
* @bit_count: number of bits in scan element
* @label: useful data for the scan el (often reg address)
* @set_state: for some devices datardy signals are generated
* for any enabled lines. This allows unwanted lines
* to be disabled and hence not get in the way.
**/
struct iio_scan_el {
struct device_attribute dev_attr;
unsigned int number;
int bit_count;
unsigned int label;
int (*set_state)(struct iio_scan_el *scanel,
struct iio_dev *dev_info,
bool state);
};
#define to_iio_scan_el(_dev_attr) \
container_of(_dev_attr, struct iio_scan_el, dev_attr);
/**
* iio_scan_el_store() - sysfs scan element selection interface
* @dev: the target device
* @attr: the device attribute that is being processed
* @buf: input from userspace
* @len: length of input
*
* A generic function used to enable various scan elements. In some
* devices explicit read commands for each channel mean this is merely
* a software switch. In others this must actively disable the channel.
* Complexities occur when this interacts with data ready type triggers
* which may not reset unless every channel that is enabled is explicitly
* read.
**/
ssize_t iio_scan_el_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len);
/**
* iio_scal_el_show() - sysfs interface to query whether a scan element is
* is enabled or not
* @dev: the target device
* @attr: the device attribute that is being processed
* @buf: output buffer
**/
ssize_t iio_scan_el_show(struct device *dev, struct device_attribute *attr,
char *buf);
ssize_t iio_scan_el_ts_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len);
ssize_t iio_scan_el_ts_show(struct device *dev, struct device_attribute *attr,
char *buf);
/**
* IIO_SCAN_EL_C - declare and initialize a scan element with a control func
*
* @_name: identifying name. Resulting struct is iio_scan_el_##_name,
* sysfs element, _name##_en.
* @_number: unique id number for the scan element.
* @_bits: number of bits in the scan element result (used in mixed bit
* length devices).
* @_label: indentification variable used by drivers. Often a reg address.
* @_controlfunc: function used to notify hardware of whether state changes
**/
#define IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc) \
struct iio_scan_el iio_scan_el_##_name = { \
.dev_attr = __ATTR(_number##_##_name##_en, \
S_IRUGO | S_IWUSR, \
iio_scan_el_show, \
iio_scan_el_store), \
.number = _number, \
.bit_count = _bits, \
.label = _label, \
.set_state = _controlfunc, \
}
#define IIO_SCAN_NAMED_EL_C(_name, _string, _number, _bits, _label, _cf) \
struct iio_scan_el iio_scan_el_##_name = { \
.dev_attr = __ATTR(_number##_##_string##_en, \
S_IRUGO | S_IWUSR, \
iio_scan_el_show, \
iio_scan_el_store), \
.number = _number, \
.bit_count = _bits, \
.label = _label, \
.set_state = _cf, \
}
/**
* IIO_SCAN_EL_TIMESTAMP - declare a special scan element for timestamps
*
* Odd one out. Handled slightly differently from other scan elements.
**/
#define IIO_SCAN_EL_TIMESTAMP(number) \
struct iio_scan_el iio_scan_el_timestamp = { \
.dev_attr = __ATTR(number##_timestamp_en, \
S_IRUGO | S_IWUSR, \
iio_scan_el_ts_show, \
iio_scan_el_ts_store), \
}
static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring)
{
put_device(&ring->dev);
};
#define to_iio_ring_buffer(d) \
container_of(d, struct iio_ring_buffer, dev)
#define access_dev_to_iio_ring_buffer(d) \
container_of(d, struct iio_ring_buffer, access_dev)
int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id);
void iio_ring_buffer_unregister(struct iio_ring_buffer *ring);
ssize_t iio_read_ring_length(struct device *dev,
struct device_attribute *attr,
char *buf);
ssize_t iio_write_ring_length(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len);
ssize_t iio_read_ring_bps(struct device *dev,
struct device_attribute *attr,
char *buf);
ssize_t iio_store_ring_enable(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len);
ssize_t iio_show_ring_enable(struct device *dev,
struct device_attribute *attr,
char *buf);
#define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR, \
iio_read_ring_length, \
iio_write_ring_length)
#define IIO_RING_BPS_ATTR DEVICE_ATTR(bps, S_IRUGO | S_IWUSR, \
iio_read_ring_bps, NULL)
#define IIO_RING_ENABLE_ATTR DEVICE_ATTR(ring_enable, S_IRUGO | S_IWUSR, \
iio_show_ring_enable, \
iio_store_ring_enable)
#endif /* _IIO_RING_GENERIC_H_ */