帮忙写个Linux下从指定fd获取dma buffer并返回其fd的代码
时间: 2023-10-29 09:05:48 浏览: 42
好的,以下是一个简单的示例代码,可以从给定的文件描述符(fd)获取DMA缓冲区并返回其文件描述符:
```c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/dma-buf.h>
int get_dma_buffer_fd(int fd)
{
struct dma_buf_sync sync_args = {0};
int dma_fd = -1;
// Get the dma_buf file descriptor
if (ioctl(fd, DMA_BUF_IOCTL_SYNC, &sync_args) == 0) {
dma_fd = ioctl(fd, DMA_BUF_IOCTL_FD);
}
return dma_fd;
}
int main(int argc, char *argv[])
{
int fd = -1;
int dma_fd = -1;
// Open the file descriptor for the DMA buffer
fd = open("/dev/dma", O_RDWR);
if (fd < 0) {
perror("Failed to open DMA buffer device");
exit(1);
}
// Get the file descriptor for the DMA buffer
dma_fd = get_dma_buffer_fd(fd);
if (dma_fd < 0) {
perror("Failed to get DMA buffer file descriptor");
exit(1);
}
// Use the DMA buffer file descriptor as needed...
printf("DMA buffer file descriptor: %d\n", dma_fd);
// Close the file descriptors
close(dma_fd);
close(fd);
return 0;
}
```
此代码假设您要从名为 `/dev/dma` 的设备获取DMA缓冲区。请根据需要修改设备名称和其他参数。