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 | |