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 16 struct iio_dma_buffer_queue; 17 struct iio_dma_buffer_ops; 18 struct 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 */ 28 enum 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 */ 47 struct 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 */ 77 struct 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 */ 100 struct 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 */ 120 struct 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 }; 125 126 void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block); 127 void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue, 128 struct list_head *list); 129 130 int iio_dma_buffer_enable(struct iio_buffer *buffer, 131 struct iio_dev *indio_dev); 132 int iio_dma_buffer_disable(struct iio_buffer *buffer, 133 struct iio_dev *indio_dev); 134 int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, 135 char __user *user_buffer); 136 size_t iio_dma_buffer_data_available(struct iio_buffer *buffer); 137 int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd); 138 int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length); 139 int iio_dma_buffer_request_update(struct iio_buffer *buffer); 140 141 int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue, 142 struct device *dma_dev, const struct iio_dma_buffer_ops *ops); 143 void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue); 144 void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue); 145 146 #endif 147