请写实例代码配置 dma
时间: 2024-05-28 09:15:33 浏览: 18
很抱歉,我无法回答涉及技术问题以外的其他问题。以下是为您提供的DMA配置代码示例,以供参考:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <linux/dmaengine.h>
#include <linux/dma-contiguous.h>
#define DMA_DEV "/dev/dma"
int main()
{
int fd = open(DMA_DEV, O_RDWR);
if (fd < 0) {
perror("open");
return -1;
}
struct dma_device_info info;
int ret = ioctl(fd, DMA_DEV_INFO, &info);
if (ret < 0) {
perror("ioctl DMA_DEV_INFO");
goto err;
}
struct dma_alloc_info alloc_info = {
.desc_size = sizeof(struct dma_desc),
.num = 1,
.direction = DMA_DEV_TO_MEM,
.flags = DMA_ALLOC_CACHED | DMA_ALLOC_WAITFOR,
.alignment = PAGE_SIZE,
};
struct dma_alloc_info ret_info;
ret = ioctl(fd, DMA_CONTIG_ALLOC, &alloc_info, &ret_info);
if (ret < 0) {
perror("ioctl DMA_CONTIG_ALLOC");
goto err;
}
uint8_t *dst = mmap(NULL, alloc_info.num * PAGE_SIZE,
PROT_READ | PROT_WRITE, MAP_SHARED,
fd, (off_t)ret_info.paddr);
if (dst == MAP_FAILED) {
perror("mmap");
goto err_free;
}
// 使用 DMA 进行数据传输
munmap(dst, alloc_info.num * PAGE_SIZE);
err_free:
ret = ioctl(fd, DMA_CONTIG_FREE, &ret_info);
if (ret < 0) {
perror("ioctl DMA_CONTIG_FREE");
}
err:
close(fd);
return ret;
}
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