kopia lustrzana https://github.com/espressif/esp-idf
85 wiersze
3.2 KiB
C
85 wiersze
3.2 KiB
C
/*
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* SPDX-FileCopyrightText: 2010-2022 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#pragma once
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#include <stdbool.h>
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#include "esp_rom_lldesc.h"
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//the size field has 12 bits, but 0 not for 4096.
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//to avoid possible problem when the size is not word-aligned, we only use 4096-4 per desc.
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/** Maximum size of data in the buffer that a DMA descriptor can hold. */
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#define LLDESC_MAX_NUM_PER_DESC (4096-4)
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// Some DMA operations might impose certain alignment restrictions on the length
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#define LLDESC_MAX_NUM_PER_DESC_16B_ALIGNED (4096 - 16)
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#define LLDESC_MAX_NUM_PER_DESC_32B_ALIGNED (4096 - 32)
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* Generate a linked list pointing to a (huge) buffer in an descriptor array.
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*
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* The caller should ensure there is enough size to hold the array, by calling
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* ``lldesc_get_required_num_constrained`` with the same max_desc_size argument.
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*
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* @param[out] out_desc_array Output of a descriptor array, the head should be fed to the DMA.
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* @param buffer Buffer for the descriptors to point to.
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* @param size Size (or length for TX) of the buffer
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* @param max_desc_size Maximum length of each descriptor
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* @param isrx The RX DMA may require the buffer to be word-aligned, set to true for a RX link, otherwise false.
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*/
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void lldesc_setup_link_constrained(lldesc_t *out_desc_array, const void *buffer, int size, int max_desc_size, bool isrx);
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/**
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* Generate a linked list pointing to a (huge) buffer in an descriptor array.
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*
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* The caller should ensure there is enough size to hold the array, by calling
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* ``lldesc_get_required_num``.
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*
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* @param[out] out_desc_array Output of a descriptor array, the head should be fed to the DMA.
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* @param buffer Buffer for the descriptors to point to.
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* @param size Size (or length for TX) of the buffer
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* @param isrx The RX DMA may require the buffer to be word-aligned, set to true for a RX link, otherwise false.
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*/
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#define lldesc_setup_link(out_desc_array, buffer, size, isrx) lldesc_setup_link_constrained(out_desc_array, buffer, size, LLDESC_MAX_NUM_PER_DESC, isrx)
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/**
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* @brief Get the received length of a linked list, until end of the link or eof.
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*
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* @param head The head of the linked list.
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* @param[out] out_next Output of the next descriptor of the EOF descriptor. Return NULL if there's no
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* EOF. Can be set to NULL if next descriptor is not needed.
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* @return The accumulation of the `len` field of all descriptors until EOF or the end of the link.
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*/
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int lldesc_get_received_len(lldesc_t* head, lldesc_t** out_next);
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/**
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* Get the number of descriptors required for a given buffer size.
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*
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* @param data_size Size to check descriptor num.
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*
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* @return Numbers required.
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*/
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static inline int lldesc_get_required_num_constrained(int data_size, int max_desc_size)
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{
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return (data_size + max_desc_size - 1) / max_desc_size;
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}
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/**
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* Get the number of descriptors required for a given buffer size.
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*
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* @param data_size Size to check descriptor num.
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* @param max_desc_size Maximum length of each descriptor
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* @return Numbers required.
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*/
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#define lldesc_get_required_num(data_size) lldesc_get_required_num_constrained(data_size, LLDESC_MAX_NUM_PER_DESC)
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#ifdef __cplusplus
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}
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#endif
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