1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _IIO_BUFFER_GENERIC_IMPL_H_ 3 #define _IIO_BUFFER_GENERIC_IMPL_H_ 4 #include <linux/sysfs.h> 5 #include <linux/kref.h> 6 7 #ifdef CONFIG_IIO_BUFFER 8 9 #include <uapi/linux/iio/buffer.h> 10 #include <linux/iio/buffer.h> 11 12 struct iio_dev; 13 struct iio_buffer; 14 15 /** 16 * INDIO_BUFFER_FLAG_FIXED_WATERMARK - Watermark level of the buffer can not be 17 * configured. It has a fixed value which will be buffer specific. 18 */ 19 #define INDIO_BUFFER_FLAG_FIXED_WATERMARK BIT(0) 20 21 /** 22 * struct iio_buffer_access_funcs - access functions for buffers. 23 * @store_to: actually store stuff to the buffer 24 * @read: try to get a specified number of bytes (must exist) 25 * @data_available: indicates how much data is available for reading from 26 * the buffer. 27 * @remove_from: remove scan from buffer. Drivers should calls this to 28 * remove a scan from a buffer. 29 * @write: try to write a number of bytes 30 * @space_available: returns the amount of bytes available in a buffer 31 * @request_update: if a parameter change has been marked, update underlying 32 * storage. 33 * @set_bytes_per_datum:set number of bytes per datum 34 * @set_length: set number of datums in buffer 35 * @enable: called if the buffer is attached to a device and the 36 * device starts sampling. Calls are balanced with 37 * @disable. 38 * @disable: called if the buffer is attached to a device and the 39 * device stops sampling. Calles are balanced with @enable. 40 * @release: called when the last reference to the buffer is dropped, 41 * should free all resources allocated by the buffer. 42 * @modes: Supported operating modes by this buffer type 43 * @flags: A bitmask combination of INDIO_BUFFER_FLAG_* 44 * 45 * The purpose of this structure is to make the buffer element 46 * modular as event for a given driver, different usecases may require 47 * different buffer designs (space efficiency vs speed for example). 48 * 49 * It is worth noting that a given buffer implementation may only support a 50 * small proportion of these functions. The core code 'should' cope fine with 51 * any of them not existing. 52 **/ 53 struct iio_buffer_access_funcs { 54 int (*store_to)(struct iio_buffer *buffer, const void *data); 55 int (*read)(struct iio_buffer *buffer, size_t n, char __user *buf); 56 size_t (*data_available)(struct iio_buffer *buffer); 57 int (*remove_from)(struct iio_buffer *buffer, void *data); 58 int (*write)(struct iio_buffer *buffer, size_t n, const char __user *buf); 59 size_t (*space_available)(struct iio_buffer *buffer); 60 61 int (*request_update)(struct iio_buffer *buffer); 62 63 int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd); 64 int (*set_length)(struct iio_buffer *buffer, unsigned int length); 65 66 int (*enable)(struct iio_buffer *buffer, struct iio_dev *indio_dev); 67 int (*disable)(struct iio_buffer *buffer, struct iio_dev *indio_dev); 68 69 void (*release)(struct iio_buffer *buffer); 70 71 unsigned int modes; 72 unsigned int flags; 73 }; 74 75 /** 76 * struct iio_buffer - general buffer structure 77 * 78 * Note that the internals of this structure should only be of interest to 79 * those writing new buffer implementations. 80 */ 81 struct iio_buffer { 82 /** @length: Number of datums in buffer. */ 83 unsigned int length; 84 85 /** @flags: File ops flags including busy flag. */ 86 unsigned long flags; 87 88 /** @bytes_per_datum: Size of individual datum including timestamp. */ 89 size_t bytes_per_datum; 90 91 /* @direction: Direction of the data stream (in/out). */ 92 enum iio_buffer_direction direction; 93 94 /** 95 * @access: Buffer access functions associated with the 96 * implementation. 97 */ 98 const struct iio_buffer_access_funcs *access; 99 100 /** @scan_mask: Bitmask used in masking scan mode elements. */ 101 long *scan_mask; 102 103 /** @demux_list: List of operations required to demux the scan. */ 104 struct list_head demux_list; 105 106 /** @pollq: Wait queue to allow for polling on the buffer. */ 107 wait_queue_head_t pollq; 108 109 /** @watermark: Number of datums to wait for poll/read. */ 110 unsigned int watermark; 111 112 /* private: */ 113 /* @scan_timestamp: Does the scan mode include a timestamp. */ 114 bool scan_timestamp; 115 116 /* @buffer_attr_list: List of buffer attributes. */ 117 struct list_head buffer_attr_list; 118 119 /* 120 * @buffer_group: Attributes of the new buffer group. 121 * Includes scan elements attributes. 122 */ 123 struct attribute_group buffer_group; 124 125 /* @attrs: Standard attributes of the buffer. */ 126 const struct iio_dev_attr **attrs; 127 128 /* @demux_bounce: Buffer for doing gather from incoming scan. */ 129 void *demux_bounce; 130 131 /* @attached_entry: Entry in the devices list of buffers attached by the driver. */ 132 struct list_head attached_entry; 133 134 /* @buffer_list: Entry in the devices list of current buffers. */ 135 struct list_head buffer_list; 136 137 /* @ref: Reference count of the buffer. */ 138 struct kref ref; 139 }; 140 141 /** 142 * iio_update_buffers() - add or remove buffer from active list 143 * @indio_dev: device to add buffer to 144 * @insert_buffer: buffer to insert 145 * @remove_buffer: buffer_to_remove 146 * 147 * Note this will tear down the all buffering and build it up again 148 */ 149 int iio_update_buffers(struct iio_dev *indio_dev, 150 struct iio_buffer *insert_buffer, 151 struct iio_buffer *remove_buffer); 152 153 /** 154 * iio_buffer_init() - Initialize the buffer structure 155 * @buffer: buffer to be initialized 156 **/ 157 void iio_buffer_init(struct iio_buffer *buffer); 158 159 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer); 160 void iio_buffer_put(struct iio_buffer *buffer); 161 162 #else /* CONFIG_IIO_BUFFER */ 163 164 static inline void iio_buffer_get(struct iio_buffer *buffer) {} 165 static inline void iio_buffer_put(struct iio_buffer *buffer) {} 166 167 #endif /* CONFIG_IIO_BUFFER */ 168 #endif /* _IIO_BUFFER_GENERIC_IMPL_H_ */ 169