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*
* 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"
#ifdef CONFIG_IIO_RING_BUFFER
struct iio_ring_buffer;
/**
* 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_bytes_per_datum:get current bytes per datum
* @set_bytes_per_datum: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_bytes_per_datum)(struct iio_ring_buffer *ring);
int (*set_bytes_per_datum)(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
* @bytes_per_datum: [DEVICE] size of individual datum including timestamp
* @bpe: [DEVICE] size of individual channel value
* @loopcount: [INTERN] number of times the ring has looped
* @scan_el_attrs: [DRIVER] control of scan elements if that scan mode
* control method is used
* @scan_count: [INTERN] the number of elements in the current scan mode
* @scan_mask: [INTERN] bitmask used in masking scan mode elements
* @scan_timestamp: [INTERN] does the scan mode include a timestamp
* @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 bytes_per_datum;
int bpe;
int loopcount;
struct attribute_group *scan_el_attrs;
int scan_count;
u32 scan_mask;
bool scan_timestamp;
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 *);
};
/**
* iio_ring_buffer_init() - Initialize the buffer structure
* @ring: buffer to be initialized
* @dev_info: the iio device the buffer is assocated with
**/
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->bytes_per_datum = 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)
* @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;
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_scan_el_show() - sysfs interface to query whether a scan element
* 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);
/**
* iio_scan_el_ts_store() - sysfs interface to set whether a timestamp is included
* in the scan.
**/
ssize_t iio_scan_el_ts_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len);
/**
* iio_scan_el_ts_show() - sysfs interface to query if a timestamp is included
* in the scan.
**/
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.
* 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, _label, _controlfunc) \
struct iio_scan_el iio_scan_el_##_name = { \
.dev_attr = __ATTR(_name##_en, \
S_IRUGO | S_IWUSR, \
iio_scan_el_show, \
iio_scan_el_store), \
.number = _number, \
.label = _label, \
.set_state = _controlfunc, \
}; \
static IIO_CONST_ATTR(_name##_index, #_number)
#define IIO_SCAN_EL_C(_name, _number, _label, _controlfunc) \
__IIO_SCAN_EL_C(_name, _number, _label, _controlfunc)
#define __IIO_SCAN_NAMED_EL_C(_name, _string, _number, _label, _cf) \
struct iio_scan_el iio_scan_el_##_name = { \
.dev_attr = __ATTR(_string##_en, \
S_IRUGO | S_IWUSR, \
iio_scan_el_show, \
iio_scan_el_store), \
.number = _number, \
.label = _label, \
.set_state = _cf, \
}; \
static struct iio_const_attr iio_const_attr_##_name##_index = { \
.string = #_number, \
.dev_attr = __ATTR(_string##_index, \
S_IRUGO, iio_read_const_attr, NULL) \
}
#define IIO_SCAN_NAMED_EL_C(_name, _string, _number, _label, _cf) \
__IIO_SCAN_NAMED_EL_C(_name, _string, _number, _label, _cf)
/**
* IIO_SCAN_EL_TIMESTAMP - declare a special scan element for timestamps
* @number: specify where in the scan order this is stored.
*
* 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(timestamp_en, \
S_IRUGO | S_IWUSR, \
iio_scan_el_ts_show, \
iio_scan_el_ts_store), \
}; \
static IIO_CONST_ATTR(timestamp_index, #number)
/**
* IIO_CONST_ATTR_SCAN_EL_TYPE - attr to specify the data format of a scan el
* @name: the scan el name (may be more general and cover a set of scan elements
* @_sign: either s or u for signed or unsigned
* @_bits: number of actual bits occuplied by the value
* @_storagebits: number of bits _bits is padded to when read out of buffer
**/
#define IIO_CONST_ATTR_SCAN_EL_TYPE(_name, _sign, _bits, _storagebits) \
IIO_CONST_ATTR(_name##_type, #_sign#_bits"/"#_storagebits);
/**
* IIO_CONST_ATTR_SCAN_EL_TYPE_WITH_SHIFT - attr to specify the data format of a scan el
* @name: the scan el name (may be more general and cover a set of scan elements
* @_sign: either s or u for signed or unsigned
* @_bits: number of actual bits occuplied by the value
* @_storagebits: number of bits _bits is padded to when read out of buffer
* @_shiftbits: number of bits _shiftbits the result must be shifted
**/
#define IIO_CONST_ATTR_SCAN_EL_TYPE_WITH_SHIFT(_name, _sign, _bits, \
_storagebits, _shiftbits) \
IIO_CONST_ATTR(_name##_type, #_sign#_bits"/"#_storagebits \
">>"#_shiftbits);
#define IIO_SCAN_EL_TYPE_SIGNED 's'
#define IIO_SCAN_EL_TYPE_UNSIGNED 'u'
/*
* These are mainly provided to allow for a change of implementation if a device
* has a large number of scan elements
*/
#define IIO_MAX_SCAN_LENGTH 31
/* note 0 used as error indicator as it doesn't make sense. */
static inline u32 iio_scan_mask_match(u32 *av_masks, u32 mask)
{
while (*av_masks) {
if (!(~*av_masks & mask))
return *av_masks;
av_masks++;
}
return 0;
}
static inline int iio_scan_mask_query(struct iio_ring_buffer *ring, int bit)
{
struct iio_dev *dev_info = ring->indio_dev;
u32 mask;
if (bit > IIO_MAX_SCAN_LENGTH)
return -EINVAL;
if (!ring->scan_mask)
return 0;
if (dev_info->available_scan_masks)
mask = iio_scan_mask_match(dev_info->available_scan_masks,
ring->scan_mask);
else
mask = ring->scan_mask;
if (!mask)
return -EINVAL;
return !!(mask & (1 << bit));
};
/**
* iio_scan_mask_set() - set particular bit in the scan mask
* @ring: the ring buffer whose scan mask we are interested in
* @bit: the bit to be set.
**/
static inline int iio_scan_mask_set(struct iio_ring_buffer *ring, int bit)
{
struct iio_dev *dev_info = ring->indio_dev;
u32 mask;
u32 trialmask = ring->scan_mask | (1 << bit);
if (bit > IIO_MAX_SCAN_LENGTH)
return -EINVAL;
if (dev_info->available_scan_masks) {
mask = iio_scan_mask_match(dev_info->available_scan_masks,
trialmask);
if (!mask)
return -EINVAL;
}
ring->scan_mask = trialmask;
ring->scan_count++;
return 0;
};
/**
* iio_scan_mask_clear() - clear a particular element from the scan mask
* @ring: the ring buffer whose scan mask we are interested in
* @bit: the bit to clear
**/
static inline int iio_scan_mask_clear(struct iio_ring_buffer *ring, int bit)
{
if (bit > IIO_MAX_SCAN_LENGTH)
return -EINVAL;
ring->scan_mask &= ~(1 << bit);
ring->scan_count--;
return 0;
};
/**
* iio_scan_mask_count_to_right() - how many scan elements occur before here
* @ring: the ring buffer whose scan mask we interested in
* @bit: which number scan element is this
**/
static inline int iio_scan_mask_count_to_right(struct iio_ring_buffer *ring,
int bit)
{
int count = 0;
int mask = (1 << bit);
if (bit > IIO_MAX_SCAN_LENGTH)
return -EINVAL;
while (mask) {
mask >>= 1;
if (mask & ring->scan_mask)
count++;
}
return count;
}
/**
* iio_put_ring_buffer() - notify done with buffer
* @ring: the buffer we are done with.
**/
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)
/**
* iio_ring_buffer_register() - register the buffer with IIO core
* @ring: the buffer to be registered
* @id: the id of the buffer (typically 0)
**/
int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id);
/**
* iio_ring_buffer_unregister() - unregister the buffer from IIO core
* @ring: the buffer to be unregistered
**/
void iio_ring_buffer_unregister(struct iio_ring_buffer *ring);
/**
* iio_read_ring_length() - attr func to get number of datums in the buffer
**/
ssize_t iio_read_ring_length(struct device *dev,
struct device_attribute *attr,
char *buf);
/**
* iio_write_ring_length() - attr func to set number of datums in the buffer
**/
ssize_t iio_write_ring_length(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len);
/**
* iio_read_ring_bytes_per_datum() - attr for number of bytes in whole datum
**/
ssize_t iio_read_ring_bytes_per_datum(struct device *dev,
struct device_attribute *attr,
char *buf);
/**
* iio_store_ring_enable() - attr to turn the buffer on
**/
ssize_t iio_store_ring_enable(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len);
/**
* iio_show_ring_enable() - attr to see if the buffer is on
**/
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_BYTES_PER_DATUM_ATTR DEVICE_ATTR(bytes_per_datum, S_IRUGO | S_IWUSR, \
iio_read_ring_bytes_per_datum, NULL)
#define IIO_RING_ENABLE_ATTR DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, \
iio_show_ring_enable, \
iio_store_ring_enable)
#else /* CONFIG_IIO_RING_BUFFER */
static inline int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id)
{
return 0;
};
static inline void iio_ring_buffer_unregister(struct iio_ring_buffer *ring)
{};
#endif /* CONFIG_IIO_RING_BUFFER */
#endif /* _IIO_RING_GENERIC_H_ */
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