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