FPGA实践教程（八）PS与PL共享DDR

版权声明：转载注明出处：邢翔瑞的技术博客https://blog.csdn.net/weixin_36474809 https://blog.csdn.net/weixin_36474809/article/details/85111550

背景：很多时候需要PS与PL共享DDR作为global memory，例如卷积之中，PS将weight in与feature写入DDR，然后PL调用DDR进行运算，再将结果写入DDR进行下一次迭代。

目的：1.  PS与PL共享DDR，读和写。并且像卷积一样需要三个指针。2.  IPcore设置变量，能通过PS能查看到IPcore运行位置。3. 运用BRAM实现一定的数据搬运。

一、IPcore编写

1.1 一种错误的接口

int share_dram_core(int write_nums,int read_nums,
					volatile float * write_ptr,volatile float *read_ptr,
					int location_idx,int write_loop_idx,int read_loop_idx,
					int read_sum){
#pragma HLS INTERFACE m_axi depth=4096 port=write_ptr offset=slave
#pragma HLS INTERFACE m_axi depth=4096 port=read_ptr offset=slave
#pragma HLS INTERFACE s_axilite port=return
#pragma HLS INTERFACE s_axilite port=write_nums
#pragma HLS INTERFACE s_axilite port=read_nums
#pragma HLS INTERFACE s_axilite port=location_idx
#pragma HLS INTERFACE s_axilite port=write_loop_idx
#pragma HLS INTERFACE s_axilite port=read_loop_idx
#pragma HLS INTERFACE s_axilite port=read_sum

DRAM上不能有两个m_axi类型的指针，否则可能会遇到重叠等问题。

1.2 IPcore代码

int share_dram_core(int write_nums,int read_nums,
					volatile float * data_ptr,
					int location_idx,int write_loop_idx,int read_loop_idx,
					int read_sum){
#pragma HLS INTERFACE m_axi depth=4096 port=data_ptr offset=slave
#pragma HLS INTERFACE s_axilite port=return register
#pragma HLS INTERFACE s_axilite port=write_nums register
#pragma HLS INTERFACE s_axilite port=read_nums register
#pragma HLS INTERFACE s_axilite port=location_idx register
#pragma HLS INTERFACE s_axilite port=write_loop_idx register
#pragma HLS INTERFACE s_axilite port=read_loop_idx register
#pragma HLS INTERFACE s_axilite port=read_sum register

	location_idx=0;
	write_loop_idx=0;
	read_loop_idx=0;
	read_sum=0;
	
	for(int read_loc=0;read_loc<read_nums;read_loc++){
		read_sum+=data_ptr[read_loc];
		read_loop_idx++;
	}
	location_idx=1;//Done read process
	
	volatile float *write_ptr=&data_ptr[read_nums];
	
	for(int write_loc=0;write_loc<write_nums;write_loc++){
		write_ptr[write_loc]=write_loc;
		write_loop_idx++;
	}
	location_idx=2;//done write process
	
	return 1; //return=1 means done
}

只要一个指针指向DRAM。

1.3 位置信息

location_idx表示IPcore当前位置，0表示刚开始，1表示完成写操作，2表示完成读操作

read_loop_idx表示当前IPcore读出DRAM的次数

write_loop_idx表示当前IPcore写入DRAM的次数

return 1表示程序运行完成且成功。

1.4 接口

  s_axilite

运用带return的s_axilite来设置IPcore的值与完成IPcore。传输位置IPcore的位置信息

  m_axi

运用主axi协议运用IPcore对DDR进行读写。只能有一个

Depth的设置问题：可能是IPcore可以读写DDR上的地址。我们设为4096（1024个4字节的浮点数）

二、testBench

2.1 程序编写

#include<stdio.h>
#include<stdlib.h>
int share_dram_core(int write_nums,int read_nums,
					volatile float * data_ptr,
					int location_idx,int write_loop_idx,int read_loop_idx,
					int read_sum);
int main(){
	int PL_write_nums=50;
	int PL_read_nums=50;
	volatile float * PL_write_ptr;
	volatile float * PL_read_ptr;
	
	PL_read_ptr=(volatile float *)malloc(sizeof(float)*(PL_read_nums+PL_write_nums));
	//PL_write_ptr=(volatile float *)malloc(sizeof(float)*PL_write_nums);
	
	//PL_read_ptr=(volatile float *)0x00ac1680;
	PL_write_ptr=&PL_read_ptr[PL_read_nums];

	printf("Initilize SUCCESS!PL_write_num is %d,PL_read_num is %d\n",PL_write_nums,PL_read_nums);
	printf("PL_read_ptr is %8x, PL_write_ptr is %8x \n",PL_write_ptr,PL_read_ptr);
	
	for(int cur_PL_read_loc=0;cur_PL_read_loc<PL_read_nums;cur_PL_read_loc++){
		PL_read_ptr[cur_PL_read_loc]=cur_PL_read_loc;
	}
	printf("PS write on PL read loc SUCCESS!\n");
	
	int result=share_dram_core(PL_write_nums,PL_read_nums,
					PL_read_ptr,
					0,0,0,0);
	
	for(int cur_PL_write_loc=0;cur_PL_write_loc<PL_write_nums;cur_PL_write_loc++){
		if(PL_write_ptr[cur_PL_write_loc]!=cur_PL_write_loc){
			printf("PL write ERROR!loc is %d, prt loc is %8x \n",&PL_write_ptr[cur_PL_write_loc]);
		}
	}
	printf("Check PL write done!\n");
	if(result==1){
		printf("IPcore result SUCCESS!\n");
	}
	
	return 0;
}

2.2 PS与PL的交互

PS传出数据很简单，但是PL传出数据不易。所以尽量以PS多输出信息来验证PL的正确性。

更多信息通过一些参数传出来。例如location_idx, write_loop_idx; read_loop_idx; read_sum;

INFO: [SIM 4] CSIM will launch GCC as the compiler.
   Compiling ../../../../src/share_dram_HLS_test.cpp in debug mode
   Generating csim.exe
Initilize SUCCESS!PL_write_num is 50,PL_read_num is 50
PL_read_ptr is   a21748, PL_write_ptr is   a21680 
PS write on PL read loc SUCCESS!
Check PL write done!
IPcore result SUCCESS!

synthesis，然后export RTL

三、系统搭建与hdf生成

运用已有的样板文件，hello world。加入HLS的IP。搭建系统。

使能GP与HP0，自动连接，create HDL wrapper，生成比特流，export到 local include bitstream

四、SDK

//created by Xing Xiangrui on 2018.12.25
//This is the SDK code to test share DRAM
//Write through PS to DDR
//Run PL : read from DDR to PL and write from PL to DDR
//Then read from DDR to PS

#include <stdio.h>
#include <xparameters.h>
//#include <stdlib.h>
//#include "platform.h"
//#include <xil_cache.h>
#include "xshare_dram_core.h"

XShare_dram_core XShare_dram_core_instance;

int main()
{
	printf("\n --------------program start------------- \n");

	//read and write param
	int ps_wirte_size=5; int ps_read_size=5;
	int core_location_idx=100;int core_write_loop_idx=100;int core_read_loop_idx=100;int core_read_sum=100;
	int core_return_value=100;
	volatile float * ps_write_ptr;
	volatile float * ps_read_ptr;

	//pointer intialize
	ps_write_ptr=(volatile float *)malloc((ps_wirte_size+ps_read_size)*sizeof(float));
	//ps_write_ptr= 0x10000000;
	ps_read_ptr=&ps_write_ptr[ps_wirte_size];
	if(ps_write_ptr==NULL)printf("Malloc ps_write_ptr failure \n");
	if(ps_read_ptr==NULL)printf("Malloc ps_read_ptr failure \n");
	memset((void*)ps_write_ptr,0,ps_wirte_size*sizeof(float));
	memset((void*)ps_read_ptr,0,ps_read_size*sizeof(float));

	printf("Initialize ps_read_ptr and ps_write_ptr SUCCESS!\n");
	printf("ps_read_ptr is %8x \n",ps_read_ptr);
	printf("ps_write_ptr is %8x \n",ps_write_ptr);

	for(int cur_print_loc=0;cur_print_loc<ps_read_size;cur_print_loc++){
		printf("location %3d, value %f \n",cur_print_loc,ps_read_ptr[cur_print_loc]);
	}

	//initialize IPcore
	XShare_dram_core_Initialize(&XShare_dram_core_instance, XPAR_SHARE_DRAM_CORE_0_DEVICE_ID);
	printf("XShare_dram_core_Initialize SUCCESS!\n");

	//get and printf values
	core_location_idx=XShare_dram_core_Get_location_idx(&XShare_dram_core_instance);
	core_write_loop_idx=XShare_dram_core_Get_write_loop_idx(&XShare_dram_core_instance);
	core_read_loop_idx=XShare_dram_core_Get_read_loop_idx(&XShare_dram_core_instance);
	core_read_sum=XShare_dram_core_Get_read_sum(&XShare_dram_core_instance);
	core_return_value=XShare_dram_core_Get_return(&XShare_dram_core_instance);
	printf("core_location_idx=%d \n",core_location_idx);
	printf("core_write_loop_idx=%d \n",core_write_loop_idx);
	printf("core_read_loop_idx=%d \n",core_read_loop_idx);
	printf("core_read_sum=%d \n",core_read_sum);
	printf("core_return_value=%d \n",core_return_value);

	//initialize IPcore value
	XShare_dram_core_Set_write_nums(&XShare_dram_core_instance, ps_read_size);
	XShare_dram_core_Set_read_nums(&XShare_dram_core_instance, ps_wirte_size);
	XShare_dram_core_Set_data_ptr(&XShare_dram_core_instance, ps_write_ptr);
	printf("-------------Core value set SUCCESS! \n");

	//get and printf values
	core_location_idx=XShare_dram_core_Get_location_idx(&XShare_dram_core_instance);
	core_write_loop_idx=XShare_dram_core_Get_write_loop_idx(&XShare_dram_core_instance);
	core_read_loop_idx=XShare_dram_core_Get_read_loop_idx(&XShare_dram_core_instance);
	core_read_sum=XShare_dram_core_Get_read_sum(&XShare_dram_core_instance);
	core_return_value=XShare_dram_core_Get_return(&XShare_dram_core_instance);
	printf("core_location_idx=%d \n",core_location_idx);
	printf("core_write_loop_idx=%d \n",core_write_loop_idx);
	printf("core_read_loop_idx=%d \n",core_read_loop_idx);
	printf("core_read_sum=%d \n",core_read_sum);
	printf("core_return_value=%d \n",core_return_value);

	//IPcore start
	XShare_dram_core_Start(&XShare_dram_core_instance);
	printf("-------------IPCore start SUCCESS! \n");

	//get and printf values
	core_location_idx=XShare_dram_core_Get_location_idx(&XShare_dram_core_instance);
	core_write_loop_idx=XShare_dram_core_Get_write_loop_idx(&XShare_dram_core_instance);
	core_read_loop_idx=XShare_dram_core_Get_read_loop_idx(&XShare_dram_core_instance);
	core_read_sum=XShare_dram_core_Get_read_sum(&XShare_dram_core_instance);
	core_return_value=XShare_dram_core_Get_return(&XShare_dram_core_instance);
	printf("core_location_idx=%d \n",core_location_idx);
	printf("core_write_loop_idx=%d \n",core_write_loop_idx);
	printf("core_read_loop_idx=%d \n",core_read_loop_idx);
	printf("core_read_sum=%d \n",core_read_sum);
	printf("core_return_value=%d \n",core_return_value);

	while(!XShare_dram_core_IsDone(&XShare_dram_core_instance)){
		printf("Calculating...\n");
	}
	printf("IsDone done SUCCESS!\n");

	//get and printf values
	core_location_idx=XShare_dram_core_Get_location_idx(&XShare_dram_core_instance);
	core_write_loop_idx=XShare_dram_core_Get_write_loop_idx(&XShare_dram_core_instance);
	core_read_loop_idx=XShare_dram_core_Get_read_loop_idx(&XShare_dram_core_instance);
	core_read_sum=XShare_dram_core_Get_read_sum(&XShare_dram_core_instance);
	core_return_value=XShare_dram_core_Get_return(&XShare_dram_core_instance);
	printf("core_location_idx=%d \n",core_location_idx);
	printf("core_write_loop_idx=%d \n",core_write_loop_idx);
	printf("core_read_loop_idx=%d \n",core_read_loop_idx);
	printf("core_read_sum=%d \n",core_read_sum);
	printf("core_return_value=%d \n",core_return_value);

	for(int cur_print_loc=0;cur_print_loc<ps_read_size;cur_print_loc++){
		printf("location %3d, value %f \n",cur_print_loc,ps_read_ptr[cur_print_loc]);
	}
	printf("-----------Program end SUCCESS!- \n\n");
	return 0;
}

用SDK打开vivado生成的文件夹下的 .sdk文件夹然后加载相应的hdf，生成bsp，创建c程序，hello world。build它。

启动FPGA，program FPGA将比特流烧录进去，然后运行程序。

4.1 用malloc的方式开辟内存

	//pointer intialize
	ps_write_ptr=(volatile float *)malloc((ps_wirte_size+ps_read_size)*sizeof(float));
	//ps_write_ptr= 0x10000000;
	ps_read_ptr=&ps_write_ptr[ps_wirte_size];
	if(ps_write_ptr==NULL)printf("Malloc ps_write_ptr failure \n");
	if(ps_read_ptr==NULL)printf("Malloc ps_read_ptr failure \n");
	memset((void*)ps_write_ptr,0,ps_wirte_size*sizeof(float));
	memset((void*)ps_read_ptr,0,ps_read_size*sizeof(float));

FPGA始终输出0，即IPcore并未有正确的动作。

 --------------program start-------------
Initialize ps_read_ptr and ps_write_ptr SUCCESS!
ps_read_ptr is   114764
ps_write_ptr is   114750
location   0, value 0.000000
location   1, value 0.000000
location   2, value 0.000000
location   3, value 0.000000
location   4, value 0.000000
XShare_dram_core_Initialize SUCCESS!
core_location_idx=0
core_write_loop_idx=0
core_read_loop_idx=0
core_read_sum=0
core_return_value=0
-------------Core value set SUCCESS!
core_location_idx=0
core_write_loop_idx=0
core_read_loop_idx=0
core_read_sum=0
core_return_value=0
-------------IPCore start SUCCESS!
core_location_idx=0
core_write_loop_idx=0
core_read_loop_idx=0
core_read_sum=0
core_return_value=0
Calculating...
Calculating...
。。。

IPcore会一直不结束。

4.2 指定指针位置

	ps_write_ptr= 0x10000000;
	ps_read_ptr=&ps_write_ptr[ps_wirte_size];
	if(ps_write_ptr==NULL)printf("Malloc ps_write_ptr failure \n");
	if(ps_read_ptr==NULL)printf("Malloc ps_read_ptr failure \n");
	memset((void*)ps_write_ptr,0,ps_wirte_size*sizeof(float));
	memset((void*)ps_read_ptr,0,ps_read_size*sizeof(float));

依然无法用IPcore写入值。

 --------------program start-------------
Initialize ps_read_ptr and ps_write_ptr SUCCESS!
ps_read_ptr is 10000014
ps_write_ptr is 10000000
location   0, value 0.000000
location   1, value 0.000000
location   2, value 0.000000
location   3, value 0.000000
location   4, value 0.000000
XShare_dram_core_Initialize SUCCESS!
core_location_idx=0
core_write_loop_idx=0
core_read_loop_idx=0
core_read_sum=0
core_return_value=1
-------------Core value set SUCCESS!
core_location_idx=0
core_write_loop_idx=0
core_read_loop_idx=0
core_read_sum=0
core_return_value=1
-------------IPCore start SUCCESS!
core_location_idx=0
core_write_loop_idx=0
core_read_loop_idx=0
core_read_sum=0
core_return_value=1
IsDone done SUCCESS!
core_location_idx=0
core_write_loop_idx=0
core_read_loop_idx=0
core_read_sum=0
core_return_value=1
location   0, value 0.000000
location   1, value 0.000000
location   2, value 0.000000
location   3, value 0.000000
location   4, value 0.000000
-----------Program end SUCCESS!-