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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/atomic.h>
11#include <linux/list.h>
12#include <linux/kref.h>
13#include <linux/spinlock.h>
14#include <linux/mutex.h>
15#include <linux/iio/buffer_impl.h>
16
17struct iio_dma_buffer_queue;
18struct iio_dma_buffer_ops;
19struct device;
20struct dma_buf_attachment;
21struct dma_fence;
22struct sg_table;
23
24/**
25 * enum iio_block_state - State of a struct iio_dma_buffer_block
26 * @IIO_BLOCK_STATE_QUEUED: Block is on the incoming queue
27 * @IIO_BLOCK_STATE_ACTIVE: Block is currently being processed by the DMA
28 * @IIO_BLOCK_STATE_DONE: Block is on the outgoing queue
29 * @IIO_BLOCK_STATE_DEAD: Block has been marked as to be freed
30 */
31enum iio_block_state {
32 IIO_BLOCK_STATE_QUEUED,
33 IIO_BLOCK_STATE_ACTIVE,
34 IIO_BLOCK_STATE_DONE,
35 IIO_BLOCK_STATE_DEAD,
36};
37
38/**
39 * struct iio_dma_buffer_block - IIO buffer block
40 * @head: List head
41 * @size: Total size of the block in bytes
42 * @bytes_used: Number of bytes that contain valid data
43 * @vaddr: Virutal address of the blocks memory
44 * @phys_addr: Physical address of the blocks memory
45 * @queue: Parent DMA buffer queue
46 * @kref: kref used to manage the lifetime of block
47 * @state: Current state of the block
48 * @cyclic: True if this is a cyclic buffer
49 * @fileio: True if this buffer is used for fileio mode
50 * @sg_table: DMA table for the transfer when transferring a DMABUF
51 * @fence: DMA fence to be signaled when a DMABUF transfer is complete
52 */
53struct iio_dma_buffer_block {
54 /* May only be accessed by the owner of the block */
55 struct list_head head;
56 size_t bytes_used;
57
58 /*
59 * Set during allocation, constant thereafter. May be accessed read-only
60 * by anybody holding a reference to the block.
61 */
62 void *vaddr;
63 dma_addr_t phys_addr;
64 size_t size;
65 struct iio_dma_buffer_queue *queue;
66
67 /* Must not be accessed outside the core. */
68 struct kref kref;
69 /*
70 * Must not be accessed outside the core. Access needs to hold
71 * queue->list_lock if the block is not owned by the core.
72 */
73 enum iio_block_state state;
74
75 bool cyclic;
76 bool fileio;
77
78 struct sg_table *sg_table;
79 struct dma_fence *fence;
80};
81
82/**
83 * struct iio_dma_buffer_queue_fileio - FileIO state for the DMA buffer
84 * @blocks: Buffer blocks used for fileio
85 * @active_block: Block being used in read()
86 * @pos: Read offset in the active block
87 * @block_size: Size of each block
88 * @next_dequeue: index of next block that will be dequeued
89 * @enabled: Whether the buffer is operating in fileio mode
90 */
91struct iio_dma_buffer_queue_fileio {
92 struct iio_dma_buffer_block *blocks[2];
93 struct iio_dma_buffer_block *active_block;
94 size_t pos;
95 size_t block_size;
96
97 unsigned int next_dequeue;
98 bool enabled;
99};
100
101/**
102 * struct iio_dma_buffer_queue - DMA buffer base structure
103 * @buffer: IIO buffer base structure
104 * @dev: Parent device
105 * @ops: DMA buffer callbacks
106 * @lock: Protects the incoming list, active and the fields in the fileio
107 * substruct
108 * @list_lock: Protects lists that contain blocks which can be modified in
109 * atomic context as well as blocks on those lists. This is the outgoing queue
110 * list and typically also a list of active blocks in the part that handles
111 * the DMA controller
112 * @incoming: List of buffers on the incoming queue
113 * @active: Whether the buffer is currently active
114 * @num_dmabufs: Total number of DMABUFs attached to this queue
115 * @fileio: FileIO state
116 */
117struct iio_dma_buffer_queue {
118 struct iio_buffer buffer;
119 struct device *dev;
120 const struct iio_dma_buffer_ops *ops;
121
122 struct mutex lock;
123 spinlock_t list_lock;
124 struct list_head incoming;
125
126 bool active;
127 atomic_t num_dmabufs;
128
129 struct iio_dma_buffer_queue_fileio fileio;
130};
131
132/**
133 * struct iio_dma_buffer_ops - DMA buffer callback operations
134 * @submit: Called when a block is submitted to the DMA controller
135 * @abort: Should abort all pending transfers
136 */
137struct iio_dma_buffer_ops {
138 int (*submit)(struct iio_dma_buffer_queue *queue,
139 struct iio_dma_buffer_block *block);
140 void (*abort)(struct iio_dma_buffer_queue *queue);
141};
142
143void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block);
144void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue,
145 struct list_head *list);
146
147int iio_dma_buffer_enable(struct iio_buffer *buffer,
148 struct iio_dev *indio_dev);
149int iio_dma_buffer_disable(struct iio_buffer *buffer,
150 struct iio_dev *indio_dev);
151int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n,
152 char __user *user_buffer);
153int iio_dma_buffer_write(struct iio_buffer *buffer, size_t n,
154 const char __user *user_buffer);
155size_t iio_dma_buffer_usage(struct iio_buffer *buffer);
156int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd);
157int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length);
158int iio_dma_buffer_request_update(struct iio_buffer *buffer);
159
160int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue,
161 struct device *dma_dev, const struct iio_dma_buffer_ops *ops);
162void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue);
163void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue);
164
165struct iio_dma_buffer_block *
166iio_dma_buffer_attach_dmabuf(struct iio_buffer *buffer,
167 struct dma_buf_attachment *attach);
168void iio_dma_buffer_detach_dmabuf(struct iio_buffer *buffer,
169 struct iio_dma_buffer_block *block);
170int iio_dma_buffer_enqueue_dmabuf(struct iio_buffer *buffer,
171 struct iio_dma_buffer_block *block,
172 struct dma_fence *fence,
173 struct sg_table *sgt,
174 size_t size, bool cyclic);
175void iio_dma_buffer_lock_queue(struct iio_buffer *buffer);
176void iio_dma_buffer_unlock_queue(struct iio_buffer *buffer);
177struct device *iio_dma_buffer_get_dma_dev(struct iio_buffer *buffer);
178
179#endif
180

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