diff --git a/sdk/software/examples/fft_dma/Makefile b/sdk/software/examples/fft_dma/Makefile new file mode 100644 index 0000000..f15dec1 --- /dev/null +++ b/sdk/software/examples/fft_dma/Makefile @@ -0,0 +1,11 @@ +TARGET = fft_dma + +CFLAGS += -O3 -g + +C_SRCS := $(wildcard ./*.c ) + +OBJDIR = obj +COMMON_DIR = ../../bsp +GCC_DIR=../../../toolchains/loongson-gnu-toolchain-8.3-x86_64-loongarch32r-linux-gnusf-v2.0 +PICOLIBC_DIR=../../../toolchains/picolibc +include ../../bsp/common.mk diff --git a/sdk/software/examples/fft_dma/main.c b/sdk/software/examples/fft_dma/main.c new file mode 100644 index 0000000..066bcd3 --- /dev/null +++ b/sdk/software/examples/fft_dma/main.c @@ -0,0 +1,205 @@ +#include +#include +#include +#include +#include +#include + +// BSP板级支持包所需全局变量 +unsigned long UART_BASE = 0xbf000000; +unsigned long CONFREG_TIMER_BASE = 0xbf20f100; +unsigned long CONFREG_CLOCKS_PER_SEC = 50000000L; +unsigned long CORE_CLOCKS_PER_SEC = 33000000L; + +#define FFT_BASE 0xbf400000 +#define FFT_IN_RE_BASE (FFT_BASE + 0x1000) +#define FFT_IN_IM_BASE (FFT_BASE + 0x2000) +#define FFT_OUT_RE_BASE (FFT_BASE + 0x3000) +#define FFT_OUT_IM_BASE (FFT_BASE + 0x4000) +#define FFT_CSR_REG (FFT_BASE + 0xF000) +#define FFT_CTRL_START (1 << 4) +#define FFT_STAT_DONE (1 << 1) +#define FFT_STAT_BUSY (1 << 0) +#define FFT_POINT_NUM 1024 + +#define DMA_BASE 0xbf300000 +#define DMA_CTRL (DMA_BASE + 0x0000) +#define DMA_LEN (DMA_BASE + 0x0004) +#define DMA_SRC_ADDR (DMA_BASE + 0x0008) +#define DMA_DST_ADDR (DMA_BASE + 0x000c) +#define DMA_STATUS (DMA_BASE + 0x0010) + +const float PI = 3.14159265358979323846; + +// DMA 传输通用封装函数 (阻塞等待模式) +void dma_transfer(uint32_t phys_src, uint32_t phys_dst, uint32_t byte_len) { + RegWrite(DMA_SRC_ADDR, phys_src); + RegWrite(DMA_DST_ADDR, phys_dst); + RegWrite(DMA_LEN, byte_len); + + // burst_len = 15(16拍), burst_size = 2(4字节), start = 1 + uint32_t ctrl_val = (15 << 6) | (2 << 3) | 0x01; + RegWrite(DMA_CTRL, ctrl_val); + + // 轮询等待 DMA 搬运完成 + while ((RegRead(DMA_STATUS) & 0x01) == 0) { + // CPU 空转等待 + } +} + +// 软件FFT实现 (基2 DIT-FFT 算法) +void sw_fft(float re[], float im[], int n) { + int i, j, k, l; + float tr, ti, ur, ui, wr, wi; + + j = 0; + for (i = 0; i < n - 1; i++) { + if (i < j) { + tr = re[i]; ti = im[i]; + re[i] = re[j]; im[i] = im[j]; + re[j] = tr; im[j] = ti; + } + k = n / 2; + while (k <= j) { + j -= k; + k /= 2; + } + j += k; + } + + for (l = 1; l < n; l *= 2) { + ur = 1.0; + ui = 0.0; + wr = cos(PI / l); + wi = -sin(PI / l); + + for (i = 0; i < n; i += 2 * l) { + ur = 1.0; + ui = 0.0; + for (j = 0; j < l; j++) { + int p = i + j; + int q = p + l; + + tr = re[q] * ur - im[q] * ui; + ti = re[q] * ui + im[q] * ur; + + re[q] = re[p] - tr; + im[q] = im[p] - ti; + re[p] += tr; + im[p] += ti; + + float next_ur = ur * wr - ui * wi; + ui = ur * wi + ui * wr; + ur = next_ur; + } + } + } +} + +// 全局对齐数组：作为 DMA 的源和目的内存 +int32_t hw_in_re_arr[FFT_POINT_NUM] __attribute__((aligned(64))); +int32_t hw_in_im_arr[FFT_POINT_NUM] __attribute__((aligned(64))); +int32_t hw_out_re_arr[FFT_POINT_NUM] __attribute__((aligned(64))); +int32_t hw_out_im_arr[FFT_POINT_NUM] __attribute__((aligned(64))); + +int main(int argc, char** argv) +{ + unsigned int fft_csr = RegRead(FFT_CSR_REG); + printf("fft_csr init = %x\n", fft_csr); + + // 获取外设的纯物理地址 (屏蔽高3位 0x1FFFFFFF) + uint32_t phys_fft_in_re = FFT_IN_RE_BASE & 0x1FFFFFFF; + uint32_t phys_fft_in_im = FFT_IN_IM_BASE & 0x1FFFFFFF; + uint32_t phys_fft_out_re = FFT_OUT_RE_BASE & 0x1FFFFFFF; + uint32_t phys_fft_out_im = FFT_OUT_IM_BASE & 0x1FFFFFFF; + + // 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 + volatile int32_t *uncached_in_re = (volatile int32_t *)(((uint32_t)hw_in_re_arr & 0x1FFFFFFF) | 0xA0000000); + volatile int32_t *uncached_in_im = (volatile int32_t *)(((uint32_t)hw_in_im_arr & 0x1FFFFFFF) | 0xA0000000); + volatile int32_t *uncached_out_re = (volatile int32_t *)(((uint32_t)hw_out_re_arr & 0x1FFFFFFF) | 0xA0000000); + volatile int32_t *uncached_out_im = (volatile int32_t *)(((uint32_t)hw_out_im_arr & 0x1FFFFFFF) | 0xA0000000); + + // 准备软件 FFT 测试数据 + float sw_in_re[FFT_POINT_NUM]; + float sw_in_im[FFT_POINT_NUM]; + + // 初始化测试波形 + for (int i = 0; i < FFT_POINT_NUM; i++) { + float dc_part = 4000.0f; + float f10_part = 8000.0f * cos(2 * PI * 10.0 * i / FFT_POINT_NUM); + float f200_part = 6000.0f * sin(2 * PI * 200.0 * i / FFT_POINT_NUM); + float f400_part = 3000.0f * sin(2 * PI * 400.0 * i / FFT_POINT_NUM); + + sw_in_re[i] = dc_part + f10_part + f200_part + f400_part; + sw_in_im[i] = 0.0f; + + // 硬件输入需要转为整数存入无缓存内存 + uncached_in_re[i] = (int32_t)sw_in_re[i]; + uncached_in_im[i] = 0; + + // 清理输出内存以防干扰 + uncached_out_re[i] = 0xDEADBEEF; + uncached_out_im[i] = 0xDEADBEEF; + } + + unsigned int tick_start, tick_end; + unsigned int hw_time, sw_time; + + // 硬件加速 FFT 测试 (纯 DMA 搬运) + printf("\n--- Starting Hardware FFT with DMA ---\n"); + tick_start = get_ns(); // 开始计时 + + uint32_t transfer_bytes = FFT_POINT_NUM * 4; // 1024个点 * 4字节 + + // MA 将数据从内存搬运到 FFT 输入外设 + dma_transfer(((uint32_t)hw_in_re_arr & 0x1FFFFFFF), phys_fft_in_re, transfer_bytes); + dma_transfer(((uint32_t)hw_in_im_arr & 0x1FFFFFFF), phys_fft_in_im, transfer_bytes); + + // 启动 FFT 并等待计算完成 + RegWrite(FFT_CSR_REG, FFT_CTRL_START); + while ((RegRead(FFT_CSR_REG) & FFT_STAT_DONE) == 0) { + // poll + } + + // DMA 将结果从 FFT 输出外设搬回内存 + dma_transfer(phys_fft_out_re, ((uint32_t)hw_out_re_arr & 0x1FFFFFFF), transfer_bytes); + dma_transfer(phys_fft_out_im, ((uint32_t)hw_out_im_arr & 0x1FFFFFFF), transfer_bytes); + + tick_end = get_ns(); // 结束计时 + hw_time = tick_end - tick_start; + + // 纯软件 FFT 测试 + printf("--- Starting Software FFT ---\n"); + tick_start = get_ns(); + + sw_fft(sw_in_re, sw_in_im, FFT_POINT_NUM); + + tick_end = get_ns(); + sw_time = tick_end - tick_start; + + // 打印对比结果 + printf("\n--- Performance Comparison ---\n"); + printf("Timer Clock Freq : %lu Hz\n", CONFREG_CLOCKS_PER_SEC); + printf("Hardware FFT Time: %u ns (%.3f ms)\n", hw_time, (float)hw_time / 1000000.0); + printf("Software FFT Time: %u ns (%.3f ms)\n", sw_time, (float)sw_time / 1000000.0); + + if (hw_time > 0) { + printf("Speedup Ratio : %.2fx\n", (float)sw_time / hw_time); + } + + printf("\n--- Verification (Only showing Bins with energy > 10) ---\n"); + for (int i = 0; i < FFT_POINT_NUM; i++) { + // CPU 通过无缓存指针读取 DMA 搬运回来的结果 + int32_t hw_re = uncached_out_re[i]; + int32_t hw_im = uncached_out_im[i]; + + if (fabs((float)hw_re) > 10 || fabs((float)hw_im) > 10) { + printf("Bin [%4d] Hz: HW(Re:%6d, Im:%6d) | SW(Re:%6d, Im:%6d)\n", + i, + hw_re, hw_im, + (int)sw_in_re[i] / FFT_POINT_NUM, (int)sw_in_im[i] / FFT_POINT_NUM); + } + } + + return 0; +} \ No newline at end of file