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 dma_buf_attachment;
13 struct dma_fence;
14 struct iio_dev;
15 struct iio_dma_buffer_block;
16 struct iio_buffer;
17 struct sg_table;
18
19 /**
20 * INDIO_BUFFER_FLAG_FIXED_WATERMARK - Watermark level of the buffer can not be
21 * configured. It has a fixed value which will be buffer specific.
22 */
23 #define INDIO_BUFFER_FLAG_FIXED_WATERMARK BIT(0)
24
25 /**
26 * struct iio_buffer_access_funcs - access functions for buffers.
27 * @store_to: actually store stuff to the buffer
28 * @read: try to get a specified number of bytes (must exist)
29 * @data_available: indicates how much data is available for reading from
30 * the buffer.
31 * @remove_from: remove scan from buffer. Drivers should calls this to
32 * remove a scan from a buffer.
33 * @write: try to write a number of bytes
34 * @space_available: returns the amount of bytes available in a buffer
35 * @request_update: if a parameter change has been marked, update underlying
36 * storage.
37 * @set_bytes_per_datum:set number of bytes per datum
38 * @set_length: set number of datums in buffer
39 * @enable: called if the buffer is attached to a device and the
40 * device starts sampling. Calls are balanced with
41 * @disable.
42 * @disable: called if the buffer is attached to a device and the
43 * device stops sampling. Calles are balanced with @enable.
44 * @release: called when the last reference to the buffer is dropped,
45 * should free all resources allocated by the buffer.
46 * @attach_dmabuf: called from userspace via ioctl to attach one external
47 * DMABUF.
48 * @detach_dmabuf: called from userspace via ioctl to detach one previously
49 * attached DMABUF.
50 * @enqueue_dmabuf: called from userspace via ioctl to queue this DMABUF
51 * object to this buffer. Requires a valid DMABUF fd, that
52 * was previouly attached to this buffer.
53 * @lock_queue: called when the core needs to lock the buffer queue;
54 * it is used when enqueueing DMABUF objects.
55 * @unlock_queue: used to unlock a previously locked buffer queue
56 * @modes: Supported operating modes by this buffer type
57 * @flags: A bitmask combination of INDIO_BUFFER_FLAG_*
58 *
59 * The purpose of this structure is to make the buffer element
60 * modular as event for a given driver, different usecases may require
61 * different buffer designs (space efficiency vs speed for example).
62 *
63 * It is worth noting that a given buffer implementation may only support a
64 * small proportion of these functions. The core code 'should' cope fine with
65 * any of them not existing.
66 **/
67 struct iio_buffer_access_funcs {
68 int (*store_to)(struct iio_buffer *buffer, const void *data);
69 int (*read)(struct iio_buffer *buffer, size_t n, char __user *buf);
70 size_t (*data_available)(struct iio_buffer *buffer);
71 int (*remove_from)(struct iio_buffer *buffer, void *data);
72 int (*write)(struct iio_buffer *buffer, size_t n, const char __user *buf);
73 size_t (*space_available)(struct iio_buffer *buffer);
74
75 int (*request_update)(struct iio_buffer *buffer);
76
77 int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
78 int (*set_length)(struct iio_buffer *buffer, unsigned int length);
79
80 int (*enable)(struct iio_buffer *buffer, struct iio_dev *indio_dev);
81 int (*disable)(struct iio_buffer *buffer, struct iio_dev *indio_dev);
82
83 void (*release)(struct iio_buffer *buffer);
84
85 struct iio_dma_buffer_block * (*attach_dmabuf)(struct iio_buffer *buffer,
86 struct dma_buf_attachment *attach);
87 void (*detach_dmabuf)(struct iio_buffer *buffer,
88 struct iio_dma_buffer_block *block);
89 int (*enqueue_dmabuf)(struct iio_buffer *buffer,
90 struct iio_dma_buffer_block *block,
91 struct dma_fence *fence, struct sg_table *sgt,
92 size_t size, bool cyclic);
93 void (*lock_queue)(struct iio_buffer *buffer);
94 void (*unlock_queue)(struct iio_buffer *buffer);
95
96 unsigned int modes;
97 unsigned int flags;
98 };
99
100 /**
101 * struct iio_buffer - general buffer structure
102 *
103 * Note that the internals of this structure should only be of interest to
104 * those writing new buffer implementations.
105 */
106 struct iio_buffer {
107 /** @length: Number of datums in buffer. */
108 unsigned int length;
109
110 /** @flags: File ops flags including busy flag. */
111 unsigned long flags;
112
113 /** @bytes_per_datum: Size of individual datum including timestamp. */
114 size_t bytes_per_datum;
115
116 /* @direction: Direction of the data stream (in/out). */
117 enum iio_buffer_direction direction;
118
119 /**
120 * @access: Buffer access functions associated with the
121 * implementation.
122 */
123 const struct iio_buffer_access_funcs *access;
124
125 /** @scan_mask: Bitmask used in masking scan mode elements. */
126 long *scan_mask;
127
128 /** @demux_list: List of operations required to demux the scan. */
129 struct list_head demux_list;
130
131 /** @pollq: Wait queue to allow for polling on the buffer. */
132 wait_queue_head_t pollq;
133
134 /** @watermark: Number of datums to wait for poll/read. */
135 unsigned int watermark;
136
137 /* private: */
138 /* @scan_timestamp: Does the scan mode include a timestamp. */
139 bool scan_timestamp;
140
141 /* @buffer_attr_list: List of buffer attributes. */
142 struct list_head buffer_attr_list;
143
144 /*
145 * @buffer_group: Attributes of the new buffer group.
146 * Includes scan elements attributes.
147 */
148 struct attribute_group buffer_group;
149
150 /* @attrs: Standard attributes of the buffer. */
151 const struct iio_dev_attr **attrs;
152
153 /* @demux_bounce: Buffer for doing gather from incoming scan. */
154 void *demux_bounce;
155
156 /* @attached_entry: Entry in the devices list of buffers attached by the driver. */
157 struct list_head attached_entry;
158
159 /* @buffer_list: Entry in the devices list of current buffers. */
160 struct list_head buffer_list;
161
162 /* @ref: Reference count of the buffer. */
163 struct kref ref;
164
165 /* @dmabufs: List of DMABUF attachments */
166 struct list_head dmabufs; /* P: dmabufs_mutex */
167
168 /* @dmabufs_mutex: Protects dmabufs */
169 struct mutex dmabufs_mutex;
170 };
171
172 /**
173 * iio_update_buffers() - add or remove buffer from active list
174 * @indio_dev: device to add buffer to
175 * @insert_buffer: buffer to insert
176 * @remove_buffer: buffer_to_remove
177 *
178 * Note this will tear down the all buffering and build it up again
179 */
180 int iio_update_buffers(struct iio_dev *indio_dev,
181 struct iio_buffer *insert_buffer,
182 struct iio_buffer *remove_buffer);
183
184 /**
185 * iio_buffer_init() - Initialize the buffer structure
186 * @buffer: buffer to be initialized
187 **/
188 void iio_buffer_init(struct iio_buffer *buffer);
189
190 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer);
191 void iio_buffer_put(struct iio_buffer *buffer);
192
193 void iio_buffer_signal_dmabuf_done(struct dma_fence *fence, int ret);
194
195 #else /* CONFIG_IIO_BUFFER */
196
197 static inline void iio_buffer_get(struct iio_buffer *buffer) {}
198 static inline void iio_buffer_put(struct iio_buffer *buffer) {}
199
200 #endif /* CONFIG_IIO_BUFFER */
201 #endif /* _IIO_BUFFER_GENERIC_IMPL_H_ */
202
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