1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright 2013-2015 Analog Devices Inc.
4 * Author: Lars-Peter Clausen <lars@metafoo.de>
5 */
6
7#ifndef __INDUSTRIALIO_DMA_BUFFER_H__
8#define __INDUSTRIALIO_DMA_BUFFER_H__
9
10#include <linux/list.h>
11#include <linux/kref.h>
12#include <linux/spinlock.h>
13#include <linux/mutex.h>
14#include <linux/iio/buffer_impl.h>
15
16struct iio_dma_buffer_queue;
17struct iio_dma_buffer_ops;
18struct device;
19
20/**
21 * enum iio_block_state - State of a struct iio_dma_buffer_block
22 * @IIO_BLOCK_STATE_DEQUEUED: Block is not queued
23 * @IIO_BLOCK_STATE_QUEUED: Block is on the incoming queue
24 * @IIO_BLOCK_STATE_ACTIVE: Block is currently being processed by the DMA
25 * @IIO_BLOCK_STATE_DONE: Block is on the outgoing queue
26 * @IIO_BLOCK_STATE_DEAD: Block has been marked as to be freed
27 */
28enum iio_block_state {
29 IIO_BLOCK_STATE_DEQUEUED,
30 IIO_BLOCK_STATE_QUEUED,
31 IIO_BLOCK_STATE_ACTIVE,
32 IIO_BLOCK_STATE_DONE,
33 IIO_BLOCK_STATE_DEAD,
34};
35
36/**
37 * struct iio_dma_buffer_block - IIO buffer block
38 * @head: List head
39 * @size: Total size of the block in bytes
40 * @bytes_used: Number of bytes that contain valid data
41 * @vaddr: Virutal address of the blocks memory
42 * @phys_addr: Physical address of the blocks memory
43 * @queue: Parent DMA buffer queue
44 * @kref: kref used to manage the lifetime of block
45 * @state: Current state of the block
46 */
47struct iio_dma_buffer_block {
48 /* May only be accessed by the owner of the block */
49 struct list_head head;
50 size_t bytes_used;
51
52 /*
53 * Set during allocation, constant thereafter. May be accessed read-only
54 * by anybody holding a reference to the block.
55 */
56 void *vaddr;
57 dma_addr_t phys_addr;
58 size_t size;
59 struct iio_dma_buffer_queue *queue;
60
61 /* Must not be accessed outside the core. */
62 struct kref kref;
63 /*
64 * Must not be accessed outside the core. Access needs to hold
65 * queue->list_lock if the block is not owned by the core.
66 */
67 enum iio_block_state state;
68};
69
70/**
71 * struct iio_dma_buffer_queue_fileio - FileIO state for the DMA buffer
72 * @blocks: Buffer blocks used for fileio
73 * @active_block: Block being used in read()
74 * @pos: Read offset in the active block
75 * @block_size: Size of each block
76 */
77struct iio_dma_buffer_queue_fileio {
78 struct iio_dma_buffer_block *blocks[2];
79 struct iio_dma_buffer_block *active_block;
80 size_t pos;
81 size_t block_size;
82};
83
84/**
85 * struct iio_dma_buffer_queue - DMA buffer base structure
86 * @buffer: IIO buffer base structure
87 * @dev: Parent device
88 * @ops: DMA buffer callbacks
89 * @lock: Protects the incoming list, active and the fields in the fileio
90 * substruct
91 * @list_lock: Protects lists that contain blocks which can be modified in
92 * atomic context as well as blocks on those lists. This is the outgoing queue
93 * list and typically also a list of active blocks in the part that handles
94 * the DMA controller
95 * @incoming: List of buffers on the incoming queue
96 * @outgoing: List of buffers on the outgoing queue
97 * @active: Whether the buffer is currently active
98 * @fileio: FileIO state
99 */
100struct iio_dma_buffer_queue {
101 struct iio_buffer buffer;
102 struct device *dev;
103 const struct iio_dma_buffer_ops *ops;
104
105 struct mutex lock;
106 spinlock_t list_lock;
107 struct list_head incoming;
108 struct list_head outgoing;
109
110 bool active;
111
112 struct iio_dma_buffer_queue_fileio fileio;
113};
114
115/**
116 * struct iio_dma_buffer_ops - DMA buffer callback operations
117 * @submit: Called when a block is submitted to the DMA controller
118 * @abort: Should abort all pending transfers
119 */
120struct iio_dma_buffer_ops {
121 int (*submit)(struct iio_dma_buffer_queue *queue,
122 struct iio_dma_buffer_block *block);
123 void (*abort)(struct iio_dma_buffer_queue *queue);
124};
125
126void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block);
127void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue,
128 struct list_head *list);
129
130int iio_dma_buffer_enable(struct iio_buffer *buffer,
131 struct iio_dev *indio_dev);
132int iio_dma_buffer_disable(struct iio_buffer *buffer,
133 struct iio_dev *indio_dev);
134int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n,
135 char __user *user_buffer);
136size_t iio_dma_buffer_data_available(struct iio_buffer *buffer);
137int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd);
138int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length);
139int iio_dma_buffer_request_update(struct iio_buffer *buffer);
140
141int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue,
142 struct device *dma_dev, const struct iio_dma_buffer_ops *ops);
143void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue);
144void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue);
145
146#endif
147

source code of linux/include/linux/iio/buffer-dma.h