205 lines
7.0 KiB
C
205 lines
7.0 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <math.h>
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#include <stdint.h>
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#include <common_func.h>
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#include <confreg_time.h>
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// BSP板级支持包所需全局变量
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unsigned long UART_BASE = 0xbf000000;
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unsigned long CONFREG_TIMER_BASE = 0xbf20f100;
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unsigned long CONFREG_CLOCKS_PER_SEC = 50000000L;
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unsigned long CORE_CLOCKS_PER_SEC = 33000000L;
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#define FFT_BASE 0xbf400000
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#define FFT_IN_RE_BASE (FFT_BASE + 0x1000)
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#define FFT_IN_IM_BASE (FFT_BASE + 0x2000)
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#define FFT_OUT_RE_BASE (FFT_BASE + 0x3000)
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#define FFT_OUT_IM_BASE (FFT_BASE + 0x4000)
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#define FFT_CSR_REG (FFT_BASE + 0xF000)
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#define FFT_CTRL_START (1 << 4)
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#define FFT_STAT_DONE (1 << 1)
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#define FFT_STAT_BUSY (1 << 0)
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#define FFT_POINT_NUM 1024
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#define DMA_BASE 0xbf300000
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#define DMA_CTRL (DMA_BASE + 0x0000)
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#define DMA_LEN (DMA_BASE + 0x0004)
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#define DMA_SRC_ADDR (DMA_BASE + 0x0008)
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#define DMA_DST_ADDR (DMA_BASE + 0x000c)
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#define DMA_STATUS (DMA_BASE + 0x0010)
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const float PI = 3.14159265358979323846;
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// DMA 传输通用封装函数 (阻塞等待模式)
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void dma_transfer(uint32_t phys_src, uint32_t phys_dst, uint32_t byte_len) {
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RegWrite(DMA_SRC_ADDR, phys_src);
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RegWrite(DMA_DST_ADDR, phys_dst);
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RegWrite(DMA_LEN, byte_len);
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// burst_len = 15(16拍), burst_size = 2(4字节), start = 1
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uint32_t ctrl_val = (15 << 6) | (2 << 3) | 0x01;
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RegWrite(DMA_CTRL, ctrl_val);
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// 轮询等待 DMA 搬运完成
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while ((RegRead(DMA_STATUS) & 0x01) == 0) {
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// CPU 空转等待
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}
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}
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// 软件FFT实现 (基2 DIT-FFT 算法)
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void sw_fft(float re[], float im[], int n) {
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int i, j, k, l;
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float tr, ti, ur, ui, wr, wi;
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j = 0;
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for (i = 0; i < n - 1; i++) {
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if (i < j) {
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tr = re[i]; ti = im[i];
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re[i] = re[j]; im[i] = im[j];
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re[j] = tr; im[j] = ti;
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}
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k = n / 2;
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while (k <= j) {
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j -= k;
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k /= 2;
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}
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j += k;
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}
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for (l = 1; l < n; l *= 2) {
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ur = 1.0;
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ui = 0.0;
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wr = cos(PI / l);
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wi = -sin(PI / l);
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for (i = 0; i < n; i += 2 * l) {
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ur = 1.0;
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ui = 0.0;
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for (j = 0; j < l; j++) {
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int p = i + j;
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int q = p + l;
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tr = re[q] * ur - im[q] * ui;
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ti = re[q] * ui + im[q] * ur;
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re[q] = re[p] - tr;
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im[q] = im[p] - ti;
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re[p] += tr;
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im[p] += ti;
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float next_ur = ur * wr - ui * wi;
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ui = ur * wi + ui * wr;
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ur = next_ur;
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}
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}
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}
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}
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// 全局对齐数组：作为 DMA 的源和目的内存
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int32_t hw_in_re_arr[FFT_POINT_NUM] __attribute__((aligned(64)));
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int32_t hw_in_im_arr[FFT_POINT_NUM] __attribute__((aligned(64)));
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int32_t hw_out_re_arr[FFT_POINT_NUM] __attribute__((aligned(64)));
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int32_t hw_out_im_arr[FFT_POINT_NUM] __attribute__((aligned(64)));
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int main(int argc, char** argv)
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{
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unsigned int fft_csr = RegRead(FFT_CSR_REG);
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printf("fft_csr init = %x\n", fft_csr);
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// 获取外设的纯物理地址 (屏蔽高3位 0x1FFFFFFF)
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uint32_t phys_fft_in_re = FFT_IN_RE_BASE & 0x1FFFFFFF;
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uint32_t phys_fft_in_im = FFT_IN_IM_BASE & 0x1FFFFFFF;
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uint32_t phys_fft_out_re = FFT_OUT_RE_BASE & 0x1FFFFFFF;
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uint32_t phys_fft_out_im = FFT_OUT_IM_BASE & 0x1FFFFFFF;
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// 获取内存数组的纯物理地址，并包装为 CPU 使用的无缓存(Uncached)指针
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volatile int32_t *uncached_in_re = (volatile int32_t *)(((uint32_t)hw_in_re_arr & 0x1FFFFFFF) | 0xA0000000);
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volatile int32_t *uncached_in_im = (volatile int32_t *)(((uint32_t)hw_in_im_arr & 0x1FFFFFFF) | 0xA0000000);
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volatile int32_t *uncached_out_re = (volatile int32_t *)(((uint32_t)hw_out_re_arr & 0x1FFFFFFF) | 0xA0000000);
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volatile int32_t *uncached_out_im = (volatile int32_t *)(((uint32_t)hw_out_im_arr & 0x1FFFFFFF) | 0xA0000000);
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// 准备软件 FFT 测试数据
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float sw_in_re[FFT_POINT_NUM];
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float sw_in_im[FFT_POINT_NUM];
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// 初始化测试波形
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for (int i = 0; i < FFT_POINT_NUM; i++) {
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float dc_part = 4000.0f;
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float f10_part = 8000.0f * cos(2 * PI * 10.0 * i / FFT_POINT_NUM);
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float f200_part = 6000.0f * sin(2 * PI * 200.0 * i / FFT_POINT_NUM);
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float f400_part = 3000.0f * sin(2 * PI * 400.0 * i / FFT_POINT_NUM);
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sw_in_re[i] = dc_part + f10_part + f200_part + f400_part;
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sw_in_im[i] = 0.0f;
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// 硬件输入需要转为整数存入无缓存内存
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uncached_in_re[i] = (int32_t)sw_in_re[i];
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uncached_in_im[i] = 0;
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// 清理输出内存以防干扰
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uncached_out_re[i] = 0xDEADBEEF;
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uncached_out_im[i] = 0xDEADBEEF;
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}
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unsigned int tick_start, tick_end;
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unsigned int hw_time, sw_time;
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// 硬件加速 FFT 测试 (纯 DMA 搬运)
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printf("\n--- Starting Hardware FFT with DMA ---\n");
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tick_start = get_ns(); // 开始计时
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uint32_t transfer_bytes = FFT_POINT_NUM * 4; // 1024个点 * 4字节
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// MA 将数据从内存搬运到 FFT 输入外设
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dma_transfer(((uint32_t)hw_in_re_arr & 0x1FFFFFFF), phys_fft_in_re, transfer_bytes);
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dma_transfer(((uint32_t)hw_in_im_arr & 0x1FFFFFFF), phys_fft_in_im, transfer_bytes);
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// 启动 FFT 并等待计算完成
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RegWrite(FFT_CSR_REG, FFT_CTRL_START);
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while ((RegRead(FFT_CSR_REG) & FFT_STAT_DONE) == 0) {
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// poll
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}
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// DMA 将结果从 FFT 输出外设搬回内存
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dma_transfer(phys_fft_out_re, ((uint32_t)hw_out_re_arr & 0x1FFFFFFF), transfer_bytes);
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dma_transfer(phys_fft_out_im, ((uint32_t)hw_out_im_arr & 0x1FFFFFFF), transfer_bytes);
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tick_end = get_ns(); // 结束计时
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hw_time = tick_end - tick_start;
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// 纯软件 FFT 测试
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printf("--- Starting Software FFT ---\n");
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tick_start = get_ns();
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sw_fft(sw_in_re, sw_in_im, FFT_POINT_NUM);
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tick_end = get_ns();
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sw_time = tick_end - tick_start;
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// 打印对比结果
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printf("\n--- Performance Comparison ---\n");
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printf("Timer Clock Freq : %lu Hz\n", CONFREG_CLOCKS_PER_SEC);
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printf("Hardware FFT Time: %u ns (%.3f ms)\n", hw_time, (float)hw_time / 1000000.0);
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printf("Software FFT Time: %u ns (%.3f ms)\n", sw_time, (float)sw_time / 1000000.0);
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if (hw_time > 0) {
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printf("Speedup Ratio : %.2fx\n", (float)sw_time / hw_time);
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}
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printf("\n--- Verification (Only showing Bins with energy > 10) ---\n");
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for (int i = 0; i < FFT_POINT_NUM; i++) {
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// CPU 通过无缓存指针读取 DMA 搬运回来的结果
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int32_t hw_re = uncached_out_re[i];
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int32_t hw_im = uncached_out_im[i];
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if (fabs((float)hw_re) > 10 || fabs((float)hw_im) > 10) {
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printf("Bin [%4d] Hz: HW(Re:%6d, Im:%6d) | SW(Re:%6d, Im:%6d)\n",
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i,
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hw_re, hw_im,
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(int)sw_in_re[i] / FFT_POINT_NUM, (int)sw_in_im[i] / FFT_POINT_NUM);
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}
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}
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return 0;
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} |