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.h>
15
16 struct iio_dma_buffer_queue;
17 struct iio_dma_buffer_ops;
18 struct device;
19
20 struct iio_buffer_block {
21 u32 size;
22 u32 bytes_used;
23 };
24
25 /**
26 * enum iio_block_state - State of a struct iio_dma_buffer_block
27 * @IIO_BLOCK_STATE_DEQUEUED: Block is not queued
28 * @IIO_BLOCK_STATE_QUEUED: Block is on the incoming queue
29 * @IIO_BLOCK_STATE_ACTIVE: Block is currently being processed by the DMA
30 * @IIO_BLOCK_STATE_DONE: Block is on the outgoing queue
31 * @IIO_BLOCK_STATE_DEAD: Block has been marked as to be freed
32 */
33 enum iio_block_state {
34 IIO_BLOCK_STATE_DEQUEUED,
35 IIO_BLOCK_STATE_QUEUED,
36 IIO_BLOCK_STATE_ACTIVE,
37 IIO_BLOCK_STATE_DONE,
38 IIO_BLOCK_STATE_DEAD,
39 };
40
41 /**
42 * struct iio_dma_buffer_block - IIO buffer block
43 * @head: List head
44 * @size: Total size of the block in bytes
45 * @bytes_used: Number of bytes that contain valid data
46 * @vaddr: Virutal address of the blocks memory
47 * @phys_addr: Physical address of the blocks memory
48 * @queue: Parent DMA buffer queue
49 * @kref: kref used to manage the lifetime of block
50 * @state: Current state of the block
51 */
52 struct iio_dma_buffer_block {
53 /* May only be accessed by the owner of the block */
54 struct list_head head;
55 size_t bytes_used;
56
57 /*
58 * Set during allocation, constant thereafter. May be accessed read-only
59 * by anybody holding a reference to the block.
60 */
61 void *vaddr;
62 dma_addr_t phys_addr;
63 size_t size;
64 struct iio_dma_buffer_queue *queue;
65
66 /* Must not be accessed outside the core. */
67 struct kref kref;
68 /*
69 * Must not be accessed outside the core. Access needs to hold
70 * queue->list_lock if the block is not owned by the core.
71 */
72 enum iio_block_state state;
73 };
74
75 /**
76 * struct iio_dma_buffer_queue_fileio - FileIO state for the DMA buffer
77 * @blocks: Buffer blocks used for fileio
78 * @active_block: Block being used in read()
79 * @pos: Read offset in the active block
80 * @block_size: Size of each block
81 */
82 struct iio_dma_buffer_queue_fileio {
83 struct iio_dma_buffer_block *blocks[2];
84 struct iio_dma_buffer_block *active_block;
85 size_t pos;
86 size_t block_size;
87 };
88
89 /**
90 * struct iio_dma_buffer_queue - DMA buffer base structure
91 * @buffer: IIO buffer base structure
92 * @dev: Parent device
93 * @ops: DMA buffer callbacks
94 * @lock: Protects the incoming list, active and the fields in the fileio
95 * substruct
96 * @list_lock: Protects lists that contain blocks which can be modified in
97 * atomic context as well as blocks on those lists. This is the outgoing queue
98 * list and typically also a list of active blocks in the part that handles
99 * the DMA controller
100 * @incoming: List of buffers on the incoming queue
101 * @outgoing: List of buffers on the outgoing queue
102 * @active: Whether the buffer is currently active
103 * @fileio: FileIO state
104 */
105 struct iio_dma_buffer_queue {
106 struct iio_buffer buffer;
107 struct device *dev;
108 const struct iio_dma_buffer_ops *ops;
109
110 struct mutex lock;
111 spinlock_t list_lock;
112 struct list_head incoming;
113 struct list_head outgoing;
114
115 bool active;
116
117 struct iio_dma_buffer_queue_fileio fileio;
118 };
119
120 /**
121 * struct iio_dma_buffer_ops - DMA buffer callback operations
122 * @submit: Called when a block is submitted to the DMA controller
123 * @abort: Should abort all pending transfers
124 */
125 struct iio_dma_buffer_ops {
126 int (*submit)(struct iio_dma_buffer_queue *queue,
127 struct iio_dma_buffer_block *block);
128 void (*abort)(struct iio_dma_buffer_queue *queue);
129 };
130
131 void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block);
132 void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue,
133 struct list_head *list);
134
135 int iio_dma_buffer_enable(struct iio_buffer *buffer,
136 struct iio_dev *indio_dev);
137 int iio_dma_buffer_disable(struct iio_buffer *buffer,
138 struct iio_dev *indio_dev);
139 int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n,
140 char __user *user_buffer);
141 size_t iio_dma_buffer_data_available(struct iio_buffer *buffer);
142 int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd);
143 int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length);
144 int iio_dma_buffer_request_update(struct iio_buffer *buffer);
145
146 int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue,
147 struct device *dma_dev, const struct iio_dma_buffer_ops *ops);
148 void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue);
149 void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue);
150
151 #endif