1 /* 2 * SPDX-FileCopyrightText: 2020-2021 Espressif Systems (Shanghai) CO LTD 3 * 4 * SPDX-License-Identifier: Apache-2.0 5 */ 6 7 #pragma once 8 9 #include <stdint.h> 10 #include "esp_assert.h" 11 12 #ifdef __cplusplus 13 extern "C" { 14 #endif 15 16 /** 17 * @brief Type of DMA descriptor 18 * 19 */ 20 typedef struct dma_descriptor_s { 21 struct { 22 uint32_t size : 12; /*!< Buffer size */ 23 uint32_t length : 12; /*!< Number of valid bytes in the buffer */ 24 uint32_t reversed24_27 : 4; /*!< Reserved */ 25 uint32_t err_eof : 1; /*!< Whether the received buffer contains error */ 26 uint32_t reserved29 : 1; /*!< Reserved */ 27 uint32_t suc_eof : 1; /*!< Whether the descriptor is the last one in the link */ 28 uint32_t owner : 1; /*!< Who is allowed to access the buffer that this descriptor points to */ 29 } dw0; /*!< Descriptor Word 0 */ 30 void *buffer; /*!< Pointer to the buffer */ 31 struct dma_descriptor_s *next; /*!< Pointer to the next descriptor (set to NULL if the descriptor is the last one, e.g. suc_eof=1) */ 32 } dma_descriptor_t; 33 34 ESP_STATIC_ASSERT(sizeof(dma_descriptor_t) == 12, "dma_descriptor_t should occupy 12 bytes in memory"); 35 36 #define DMA_DESCRIPTOR_BUFFER_OWNER_CPU (0) /*!< DMA buffer is allowed to be accessed by CPU */ 37 #define DMA_DESCRIPTOR_BUFFER_OWNER_DMA (1) /*!< DMA buffer is allowed to be accessed by DMA engine */ 38 #define DMA_DESCRIPTOR_BUFFER_MAX_SIZE (4095) /*!< Maximum size of the buffer that can be attached to descriptor */ 39 #define DMA_DESCRIPTOR_BUFFER_MAX_SIZE_4B_ALIGNED (4095-3) /*!< Maximum size of the buffer that can be attached to descriptor, and aligned to 4B */ 40 41 42 #ifdef __cplusplus 43 } 44 #endif 45
