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 152