1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
/* The industrial I/O core - generic 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_BUFFER_GENERIC_H_
#define _IIO_BUFFER_GENERIC_H_
#include <linux/sysfs.h>
#include <linux/iio/iio.h>
#include <linux/kref.h>
#ifdef CONFIG_IIO_BUFFER
struct iio_buffer;
/**
* struct iio_buffer_access_funcs - access functions for buffers.
* @store_to: actually store stuff to the buffer
* @read_first_n: try to get a specified number of bytes (must exist)
* @data_available: indicates whether data for reading from the buffer is
* available.
* @request_update: if a parameter change has been marked, update underlying
* storage.
* @set_bytes_per_datum:set number of bytes per datum
* @set_length: set number of datums in buffer
* @release: called when the last reference to the buffer is dropped,
* should free all resources allocated by the buffer.
*
* The purpose of this structure is to make the buffer element
* modular as event for a given driver, different usecases may require
* different buffer designs (space efficiency vs speed for example).
*
* It is worth noting that a given buffer implementation may only support a
* small proportion of these functions. The core code 'should' cope fine with
* any of them not existing.
**/
struct iio_buffer_access_funcs {
int (*store_to)(struct iio_buffer *buffer, const void *data);
int (*read_first_n)(struct iio_buffer *buffer,
size_t n,
char __user *buf);
bool (*data_available)(struct iio_buffer *buffer);
int (*request_update)(struct iio_buffer *buffer);
int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
int (*set_length)(struct iio_buffer *buffer, int length);
void (*release)(struct iio_buffer *buffer);
};
/**
* struct iio_buffer - general buffer structure
* @length: [DEVICE] number of datums in buffer
* @bytes_per_datum: [DEVICE] size of individual datum including timestamp
* @scan_el_attrs: [DRIVER] control of scan elements if that scan mode
* control method is used
* @scan_mask: [INTERN] bitmask used in masking scan mode elements
* @scan_timestamp: [INTERN] does the scan mode include a timestamp
* @access: [DRIVER] buffer access functions associated with the
* implementation.
* @scan_el_dev_attr_list:[INTERN] list of scan element related attributes.
* @scan_el_group: [DRIVER] attribute group for those attributes not
* created from the iio_chan_info array.
* @pollq: [INTERN] wait queue to allow for polling on the buffer.
* @stufftoread: [INTERN] flag to indicate new data.
* @demux_list: [INTERN] list of operations required to demux the scan.
* @demux_bounce: [INTERN] buffer for doing gather from incoming scan.
* @buffer_list: [INTERN] entry in the devices list of current buffers.
* @ref: [INTERN] reference count of the buffer.
*/
struct iio_buffer {
int length;
int bytes_per_datum;
struct attribute_group *scan_el_attrs;
long *scan_mask;
bool scan_timestamp;
const struct iio_buffer_access_funcs *access;
struct list_head scan_el_dev_attr_list;
struct attribute_group buffer_group;
struct attribute_group scan_el_group;
wait_queue_head_t pollq;
bool stufftoread;
const struct attribute **attrs;
struct list_head demux_list;
void *demux_bounce;
struct list_head buffer_list;
struct kref ref;
};
/**
* iio_update_buffers() - add or remove buffer from active list
* @indio_dev: device to add buffer to
* @insert_buffer: buffer to insert
* @remove_buffer: buffer_to_remove
*
* Note this will tear down the all buffering and build it up again
*/
int iio_update_buffers(struct iio_dev *indio_dev,
struct iio_buffer *insert_buffer,
struct iio_buffer *remove_buffer);
/**
* iio_buffer_init() - Initialize the buffer structure
* @buffer: buffer to be initialized
**/
void iio_buffer_init(struct iio_buffer *buffer);
int iio_scan_mask_query(struct iio_dev *indio_dev,
struct iio_buffer *buffer, int bit);
/**
* iio_push_to_buffers() - push to a registered buffer.
* @indio_dev: iio_dev structure for device.
* @data: Full scan.
*/
int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data);
/*
* iio_push_to_buffers_with_timestamp() - push data and timestamp to buffers
* @indio_dev: iio_dev structure for device.
* @data: sample data
* @timestamp: timestamp for the sample data
*
* Pushes data to the IIO device's buffers. If timestamps are enabled for the
* device the function will store the supplied timestamp as the last element in
* the sample data buffer before pushing it to the device buffers. The sample
* data buffer needs to be large enough to hold the additional timestamp
* (usually the buffer should be indio->scan_bytes bytes large).
*
* Returns 0 on success, a negative error code otherwise.
*/
static inline int iio_push_to_buffers_with_timestamp(struct iio_dev *indio_dev,
void *data, int64_t timestamp)
{
if (indio_dev->scan_timestamp) {
size_t ts_offset = indio_dev->scan_bytes / sizeof(int64_t) - 1;
((int64_t *)data)[ts_offset] = timestamp;
}
return iio_push_to_buffers(indio_dev, data);
}
int iio_update_demux(struct iio_dev *indio_dev);
bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
const unsigned long *mask);
struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer);
void iio_buffer_put(struct iio_buffer *buffer);
/**
* iio_device_attach_buffer - Attach a buffer to a IIO device
* @indio_dev: The device the buffer should be attached to
* @buffer: The buffer to attach to the device
*
* This function attaches a buffer to a IIO device. The buffer stays attached to
* the device until the device is freed. The function should only be called at
* most once per device.
*/
static inline void iio_device_attach_buffer(struct iio_dev *indio_dev,
struct iio_buffer *buffer)
{
indio_dev->buffer = iio_buffer_get(buffer);
}
#else /* CONFIG_IIO_BUFFER */
static inline void iio_buffer_get(struct iio_buffer *buffer) {}
static inline void iio_buffer_put(struct iio_buffer *buffer) {}
#endif /* CONFIG_IIO_BUFFER */
#endif /* _IIO_BUFFER_GENERIC_H_ */
|
