Zynq-Linux移植学习笔记之30-用户程序读写DDR

1、背景介绍

最近项目中需要做一个JTAG测试功能，该功能是需要在DDR的一段空间中准备一组数据，发送出去，再用DDR的另一段空间收数，判断收到的数是否和发送的数据相同，以此加以验证。为此，需要在ZYNQ PL中实现GPIO通过HP读写DDR实地址的操作，同时在PS中通过ARM实现对发送和接收两段内存区域的读写操作。

2、实现方法

linux中提供了dev/mem来对DDR进行读写，让应用程序可以直接读写DDR实地址，很显然，这里也将采用这一方法。需要注意的是，在映射的过程中一定要加上O_SYNC标志位，这样才能保证Dcache和DDR中数据的一致性，确保读写时不光写入Dcache，也写入DDR中。

代码如下：

/*
 * Copyright (c) 2012 Xilinx, Inc.  All rights reserved.
 *
 * Xilinx, Inc.
 * XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS" AS A
 * COURTESY TO YOU.  BY PROVIDING THIS DESIGN, CODE, OR INFORMATION AS
 * ONE POSSIBLE   IMPLEMENTATION OF THIS FEATURE, APPLICATION OR
 * STANDARD, XILINX IS MAKING NO REPRESENTATION THAT THIS IMPLEMENTATION
 * IS FREE FROM ANY CLAIMS OF INFRINGEMENT, AND YOU ARE RESPONSIBLE
 * FOR OBTAINING ANY RIGHTS YOU MAY REQUIRE FOR YOUR IMPLEMENTATION.
 * XILINX EXPRESSLY DISCLAIMS ANY WARRANTY WHATSOEVER WITH RESPECT TO
 * THE ADEQUACY OF THE IMPLEMENTATION, INCLUDING BUT NOT LIMITED TO
 * ANY WARRANTIES OR REPRESENTATIONS THAT THIS IMPLEMENTATION IS FREE
 * FROM CLAIMS OF INFRINGEMENT, IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 */

#include 
#include 
#include 
#include 
//#include 

#include "gpio.h"

void gpio_init()
{
	int temp;
	int Delay;
	SetGpioReg(GPIO_STATE_ADDR,0,0);

	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|jtx07_sbs;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|jtx07_tlr_trst;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|jtx07_tlr_trst6;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|jtag_oe_n;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	//set ddr send addr and recv addr
	SetGpioReg(GPIO_ADDR,0,0x10000000);
	SetGpioReg(GPIO_ADDR,8,0x20000000);

	//set test data length
	SetGpioReg(GPIO_WR_LEN_ADDR,0,sector_length);
	SetGpioReg(GPIO_WR_LEN_ADDR,8,sector_length);

	//set jtag test clk
	SetGpioReg(GPIO_JTAG_SEL_ADDR,0,TCK_1_MHz);

	//release reset signal
	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|FPGA_RSTn;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|jtx07_reset;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	for (Delay = 0; Delay < 8000000; Delay++);

	//enable jtag test
	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|jtag_oe_n;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	for (Delay = 0; Delay < 8000000; Delay++);

	//led trigger
	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|LED0;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

}

int main()
{
	int i;
	int fd;
	int temp;
	int Delay;
	int *start;
	int *start_test;
	int buf[1024*1024];

	for(i=0;i<1024;i++)
	{
		buf[i]=i;
	}
#if 1
	gpio_init();
#endif
	//open /dev/mem with read and write mode
	fd = open ("/dev/mem", O_RDWR | O_SYNC);
	if (fd < 0)
	{
		printf("cannot open /dev/mem.");
		return -1;
	}
	//map physical memory 0-80M bytes
	start = (int *)mmap(NULL, 0x400000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0x10000000);
	if(start < 0)
	{
		printf("mmap failed.");
		return -1;
	}
	//write memory
	memcpy(start, buf, 1024*1024);

//	cacheflush(start,1024*4,DCACHE);

//	flush_cache_all();
#if 1
	//Read value
	for (i = 0;i <1024;i++)
	{
		printf("old mem[%d]:%x\n", i,*(start + i));
	}
#endif

	munmap(start, 0x400000); //destroy map memory

#if 1

	printf("################################show new ddr################################\n");
	start_test = (int *)mmap(NULL, 0x400000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0x20000000);
	if(start_test < 0)
	{
		printf("mmap failed.");
		return -1;
	}
	for (i = 0;i <1024;i++)
	{
		printf("new mem[%d]:%x\n", i,*(start_test + i));
	}
	munmap(start_test, 0x400000); //destroy map memory

	printf("################################before jtag start################################\n");
#endif

#if 1
	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|sjtag_test_prepare;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	for (Delay = 0; Delay < 80000000; Delay++);

	temp=GetGpioReg(GPIO_STATE_ADDR,8);
	printf("JTAG STATE IS 0x%x\n",(temp & 0xFFF00000)>>20);


	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|sjtag_test_start;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);
	printf("JTAG TEST START\n");

	for (Delay = 0; Delay < 80000000; Delay++);

	temp=GetGpioReg(GPIO_STATE_ADDR,8);
	printf("JTAG STATE IS 0x%x\n",(temp & 0xFFF00000)>>20);

	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp&~sjtag_test_start;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp&~FPGA_RSTn;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp&~sjtag_test_prepare;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	temp=GetGpioReg(GPIO_STATE_ADDR,8);
	printf("JTAG STATE IS 0x%x\n",(temp & 0xFFF00000)>>20);

	temp=GetGpioReg(GPIO_STATE_ADDR,0);
	temp=temp|FPGA_RSTn;
	SetGpioReg(GPIO_STATE_ADDR,0,temp);

	temp=GetGpioReg(GPIO_STATE_ADDR,8);
	printf("JTAG STATE IS 0x%x\n",(temp & 0xFFF00000)>>20);
#endif

	printf("###########################after jtag start################################\n");
	start = (int *)mmap(NULL, 0x400000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0x20000000);
	if(start < 0)
	{
		printf("mmap failed.");
		return -1;
	}
	for (i = 0;i <1024;i++)
	{
		printf("new mem[%d]:%x\n", i,*(start + i));
	}
	munmap(start, 0x400000); //destroy map memory

	close(fd); //close file
	return 0;
}

上面代码中DDR发送区域物理起始地址为0x10000000，大小为0x400000

接收区域物理起始地址为0x20000000,大小为0x400000。