OVMS3-idf/components/soc/include/soc/lldesc.h
Konstantin Kondrashov 3ddab0b8f3 soc: Add xxx_periph.h for all modules
The "xxx_periph" header file includes all SOC-level definitions for that peripheral.

Closes: IDF-192
2019-06-03 13:56:54 +08:00

47 lines
1.8 KiB
C

// Copyright 2010-2019 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#pragma once
#include <stdbool.h>
#include "esp32/rom/lldesc.h"
//the size field has 12 bits, but 0 not for 4096.
//to avoid possible problem when the size is not word-aligned, we only use 4096-4 per desc.
/** Maximum size of data in the buffer that a DMA descriptor can hold. */
#define LLDESC_MAX_NUM_PER_DESC (4096-4)
/**
* Generate a linked list pointing to a (huge) buffer in an descriptor array.
*
* The caller should ensure there is enough size to hold the array, by calling
* ``lldesc_get_required_num``.
*
* @param out_desc_array Output of a descriptor array, the head should be fed to the DMA.
* @param buffer Buffer for the descriptors to point to.
* @param size Size (or length for TX) of the buffer
* @param isrx The RX DMA may require the buffer to be word-aligned, set to true for a RX link, otherwise false.
*/
void lldesc_setup_link(lldesc_t *out_desc_array, const void *buffer, int size, bool isrx);
/**
* Get the number of descriptors required for a given buffer size.
*
* @param data_size Size to check descriptor num.
*
* @return Numbers required.
*/
static inline int lldesc_get_required_num(int data_size)
{
return (data_size + LLDESC_MAX_NUM_PER_DESC - 1) / LLDESC_MAX_NUM_PER_DESC;
}