1/* The industrial I/O core - generic buffer interfaces. 2 * 3 * Copyright (c) 2008 Jonathan Cameron 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 as published by 7 * the Free Software Foundation. 8 */ 9 10#ifndef _IIO_BUFFER_GENERIC_H_ 11#define _IIO_BUFFER_GENERIC_H_ 12#include <linux/sysfs.h> 13#include <linux/iio/iio.h> 14#include <linux/kref.h> 15 16#ifdef CONFIG_IIO_BUFFER 17 18struct iio_buffer; 19 20/** 21 * struct iio_buffer_access_funcs - access functions for buffers. 22 * @store_to: actually store stuff to the buffer 23 * @read_first_n: try to get a specified number of bytes (must exist) 24 * @data_available: indicates how much data is available for reading from 25 * the buffer. 26 * @request_update: if a parameter change has been marked, update underlying 27 * storage. 28 * @set_bytes_per_datum:set number of bytes per datum 29 * @set_length: set number of datums in buffer 30 * @release: called when the last reference to the buffer is dropped, 31 * should free all resources allocated by the buffer. 32 * @modes: Supported operating modes by this buffer type 33 * 34 * The purpose of this structure is to make the buffer element 35 * modular as event for a given driver, different usecases may require 36 * different buffer designs (space efficiency vs speed for example). 37 * 38 * It is worth noting that a given buffer implementation may only support a 39 * small proportion of these functions. The core code 'should' cope fine with 40 * any of them not existing. 41 **/ 42struct iio_buffer_access_funcs { 43 int (*store_to)(struct iio_buffer *buffer, const void *data); 44 int (*read_first_n)(struct iio_buffer *buffer, 45 size_t n, 46 char __user *buf); 47 size_t (*data_available)(struct iio_buffer *buffer); 48 49 int (*request_update)(struct iio_buffer *buffer); 50 51 int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd); 52 int (*set_length)(struct iio_buffer *buffer, int length); 53 54 void (*release)(struct iio_buffer *buffer); 55 56 unsigned int modes; 57}; 58 59/** 60 * struct iio_buffer - general buffer structure 61 * @length: [DEVICE] number of datums in buffer 62 * @bytes_per_datum: [DEVICE] size of individual datum including timestamp 63 * @scan_el_attrs: [DRIVER] control of scan elements if that scan mode 64 * control method is used 65 * @scan_mask: [INTERN] bitmask used in masking scan mode elements 66 * @scan_timestamp: [INTERN] does the scan mode include a timestamp 67 * @access: [DRIVER] buffer access functions associated with the 68 * implementation. 69 * @scan_el_dev_attr_list:[INTERN] list of scan element related attributes. 70 * @scan_el_group: [DRIVER] attribute group for those attributes not 71 * created from the iio_chan_info array. 72 * @pollq: [INTERN] wait queue to allow for polling on the buffer. 73 * @stufftoread: [INTERN] flag to indicate new data. 74 * @demux_list: [INTERN] list of operations required to demux the scan. 75 * @demux_bounce: [INTERN] buffer for doing gather from incoming scan. 76 * @buffer_list: [INTERN] entry in the devices list of current buffers. 77 * @ref: [INTERN] reference count of the buffer. 78 * @watermark: [INTERN] number of datums to wait for poll/read. 79 */ 80struct iio_buffer { 81 int length; 82 int bytes_per_datum; 83 struct attribute_group *scan_el_attrs; 84 long *scan_mask; 85 bool scan_timestamp; 86 const struct iio_buffer_access_funcs *access; 87 struct list_head scan_el_dev_attr_list; 88 struct attribute_group buffer_group; 89 struct attribute_group scan_el_group; 90 wait_queue_head_t pollq; 91 bool stufftoread; 92 const struct attribute **attrs; 93 struct list_head demux_list; 94 void *demux_bounce; 95 struct list_head buffer_list; 96 struct kref ref; 97 unsigned int watermark; 98}; 99 100/** 101 * iio_update_buffers() - add or remove buffer from active list 102 * @indio_dev: device to add buffer to 103 * @insert_buffer: buffer to insert 104 * @remove_buffer: buffer_to_remove 105 * 106 * Note this will tear down the all buffering and build it up again 107 */ 108int iio_update_buffers(struct iio_dev *indio_dev, 109 struct iio_buffer *insert_buffer, 110 struct iio_buffer *remove_buffer); 111 112/** 113 * iio_buffer_init() - Initialize the buffer structure 114 * @buffer: buffer to be initialized 115 **/ 116void iio_buffer_init(struct iio_buffer *buffer); 117 118int iio_scan_mask_query(struct iio_dev *indio_dev, 119 struct iio_buffer *buffer, int bit); 120 121/** 122 * iio_push_to_buffers() - push to a registered buffer. 123 * @indio_dev: iio_dev structure for device. 124 * @data: Full scan. 125 */ 126int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data); 127 128/* 129 * iio_push_to_buffers_with_timestamp() - push data and timestamp to buffers 130 * @indio_dev: iio_dev structure for device. 131 * @data: sample data 132 * @timestamp: timestamp for the sample data 133 * 134 * Pushes data to the IIO device's buffers. If timestamps are enabled for the 135 * device the function will store the supplied timestamp as the last element in 136 * the sample data buffer before pushing it to the device buffers. The sample 137 * data buffer needs to be large enough to hold the additional timestamp 138 * (usually the buffer should be indio->scan_bytes bytes large). 139 * 140 * Returns 0 on success, a negative error code otherwise. 141 */ 142static inline int iio_push_to_buffers_with_timestamp(struct iio_dev *indio_dev, 143 void *data, int64_t timestamp) 144{ 145 if (indio_dev->scan_timestamp) { 146 size_t ts_offset = indio_dev->scan_bytes / sizeof(int64_t) - 1; 147 ((int64_t *)data)[ts_offset] = timestamp; 148 } 149 150 return iio_push_to_buffers(indio_dev, data); 151} 152 153int iio_update_demux(struct iio_dev *indio_dev); 154 155bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev, 156 const unsigned long *mask); 157 158struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer); 159void iio_buffer_put(struct iio_buffer *buffer); 160 161/** 162 * iio_device_attach_buffer - Attach a buffer to a IIO device 163 * @indio_dev: The device the buffer should be attached to 164 * @buffer: The buffer to attach to the device 165 * 166 * This function attaches a buffer to a IIO device. The buffer stays attached to 167 * the device until the device is freed. The function should only be called at 168 * most once per device. 169 */ 170static inline void iio_device_attach_buffer(struct iio_dev *indio_dev, 171 struct iio_buffer *buffer) 172{ 173 indio_dev->buffer = iio_buffer_get(buffer); 174} 175 176#else /* CONFIG_IIO_BUFFER */ 177 178static inline void iio_buffer_get(struct iio_buffer *buffer) {} 179static inline void iio_buffer_put(struct iio_buffer *buffer) {} 180 181#endif /* CONFIG_IIO_BUFFER */ 182 183#endif /* _IIO_BUFFER_GENERIC_H_ */ 184