1 /* 2 * Copyright 2013-2015 Analog Devices Inc. 3 * Author: Lars-Peter Clausen <lars@metafoo.de> 4 * 5 * Licensed under the GPL-2. 6 */ 7 8 #ifndef __INDUSTRIALIO_DMA_BUFFER_H__ 9 #define __INDUSTRIALIO_DMA_BUFFER_H__ 10 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.h> 16 17 struct iio_dma_buffer_queue; 18 struct iio_dma_buffer_ops; 19 struct device; 20 21 struct iio_buffer_block { 22 u32 size; 23 u32 bytes_used; 24 }; 25 26 /** 27 * enum iio_block_state - State of a struct iio_dma_buffer_block 28 * @IIO_BLOCK_STATE_DEQUEUED: Block is not queued 29 * @IIO_BLOCK_STATE_QUEUED: Block is on the incoming queue 30 * @IIO_BLOCK_STATE_ACTIVE: Block is currently being processed by the DMA 31 * @IIO_BLOCK_STATE_DONE: Block is on the outgoing queue 32 * @IIO_BLOCK_STATE_DEAD: Block has been marked as to be freed 33 */ 34 enum iio_block_state { 35 IIO_BLOCK_STATE_DEQUEUED, 36 IIO_BLOCK_STATE_QUEUED, 37 IIO_BLOCK_STATE_ACTIVE, 38 IIO_BLOCK_STATE_DONE, 39 IIO_BLOCK_STATE_DEAD, 40 }; 41 42 /** 43 * struct iio_dma_buffer_block - IIO buffer block 44 * @head: List head 45 * @size: Total size of the block in bytes 46 * @bytes_used: Number of bytes that contain valid data 47 * @vaddr: Virutal address of the blocks memory 48 * @phys_addr: Physical address of the blocks memory 49 * @queue: Parent DMA buffer queue 50 * @kref: kref used to manage the lifetime of block 51 * @state: Current state of the block 52 */ 53 struct 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 76 /** 77 * struct iio_dma_buffer_queue_fileio - FileIO state for the DMA buffer 78 * @blocks: Buffer blocks used for fileio 79 * @active_block: Block being used in read() 80 * @pos: Read offset in the active block 81 * @block_size: Size of each block 82 */ 83 struct iio_dma_buffer_queue_fileio { 84 struct iio_dma_buffer_block *blocks[2]; 85 struct iio_dma_buffer_block *active_block; 86 size_t pos; 87 size_t block_size; 88 }; 89 90 /** 91 * struct iio_dma_buffer_queue - DMA buffer base structure 92 * @buffer: IIO buffer base structure 93 * @dev: Parent device 94 * @ops: DMA buffer callbacks 95 * @lock: Protects the incoming list, active and the fields in the fileio 96 * substruct 97 * @list_lock: Protects lists that contain blocks which can be modified in 98 * atomic context as well as blocks on those lists. This is the outgoing queue 99 * list and typically also a list of active blocks in the part that handles 100 * the DMA controller 101 * @incoming: List of buffers on the incoming queue 102 * @outgoing: List of buffers on the outgoing queue 103 * @active: Whether the buffer is currently active 104 * @fileio: FileIO state 105 */ 106 struct iio_dma_buffer_queue { 107 struct iio_buffer buffer; 108 struct device *dev; 109 const struct iio_dma_buffer_ops *ops; 110 111 struct mutex lock; 112 spinlock_t list_lock; 113 struct list_head incoming; 114 struct list_head outgoing; 115 116 bool active; 117 118 struct iio_dma_buffer_queue_fileio fileio; 119 }; 120 121 /** 122 * struct iio_dma_buffer_ops - DMA buffer callback operations 123 * @submit: Called when a block is submitted to the DMA controller 124 * @abort: Should abort all pending transfers 125 */ 126 struct iio_dma_buffer_ops { 127 int (*submit)(struct iio_dma_buffer_queue *queue, 128 struct iio_dma_buffer_block *block); 129 void (*abort)(struct iio_dma_buffer_queue *queue); 130 }; 131 132 void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block); 133 void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue, 134 struct list_head *list); 135 136 int iio_dma_buffer_enable(struct iio_buffer *buffer, 137 struct iio_dev *indio_dev); 138 int iio_dma_buffer_disable(struct iio_buffer *buffer, 139 struct iio_dev *indio_dev); 140 int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, 141 char __user *user_buffer); 142 size_t iio_dma_buffer_data_available(struct iio_buffer *buffer); 143 int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd); 144 int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length); 145 int iio_dma_buffer_request_update(struct iio_buffer *buffer); 146 147 int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue, 148 struct device *dma_dev, const struct iio_dma_buffer_ops *ops); 149 void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue); 150 void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue); 151 152 #endif 153