1、 背景介绍
在板上，ZYNQ PL部分通过EMC连接一片NOR FLASH，地址空间如下：
可以看到NOR FLASH的起始地址为0x80000000，这是物理地址，可以把数据存放在以该地址起始的一段区域。
需要注意的是，在对NOR FLASH进行读写数据时，需要参考对应的datasheet，例如这里选用的NOR FLASH读、写、擦除步骤如下：
通过上面的表格就知道进行相应操作每一步该做什么，可以转换为SDK中裸奔程序的C代码。
2、 Linux下flash操作
之前提到过zynq中Linux用户应用程序可以通过/dev/mem访问到物理地址，xil_in32和xil_out32等裸奔程序中常见的函数可以通过这一机制移植到linux下。于是，对flash的操作其实就是基于xil_in和xil_out对物理地址进行读写。
这里只需要实现三个函数，erase，write_sector以及read_sector.代码如下：
//xil_io.h#include <stdio.h>#include <stdlib.h>#include <stdint.h>#include <string.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/mman.h>#include <unistd.h>#include <fcntl.h>#define PAGE_SIZE ((size_t)getpagesize())#define PAGE_MASK ((uint64_t) (long)~(PAGE_SIZE - 1))void Xil_Out32(uint64_t phyaddr, uint32_t val){int fd;volatile uint8_t *map_base;uint64_t base = phyaddr & PAGE_MASK;uint64_t pgoffset = phyaddr & (~PAGE_MASK);if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1){perror("open /dev/mem:");}map_base = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,fd, base);if(map_base == MAP_FAILED){perror("mmap:");}*(volatile uint32_t *)(map_base + pgoffset) = val; close(fd);munmap((void *)map_base, PAGE_SIZE);}int Xil_In32(uint64_t phyaddr){int fd;uint32_t val;volatile uint8_t *map_base;uint64_t base = phyaddr & PAGE_MASK;uint64_t pgoffset = phyaddr & (~PAGE_MASK);//open /dev/memif((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1){perror("open /dev/mem:");}//mmapmap_base = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,fd, base);if(map_base == MAP_FAILED){perror("mmap:");}val = *(volatile uint32_t *)(map_base + pgoffset);close(fd);munmap((void *)map_base, PAGE_SIZE);return val;}void Xil_Out16(uint64_t phyaddr, uint16_t val){int fd;volatile uint8_t *map_base;uint64_t base = phyaddr & PAGE_MASK;uint64_t pgoffset = phyaddr & (~PAGE_MASK);if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1){perror("open /dev/mem:");}map_base = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,fd, base);if(map_base == MAP_FAILED){perror("mmap:");}*(volatile uint16_t *)(map_base + pgoffset) = val; close(fd);munmap((void *)map_base, PAGE_SIZE);}int Xil_In16(uint64_t phyaddr){int fd;uint16_t val;volatile uint8_t *map_base;uint64_t base = phyaddr & PAGE_MASK;uint64_t pgoffset = phyaddr & (~PAGE_MASK);//open /dev/memif((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1){perror("open /dev/mem:");}//mmapmap_base = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,fd, base);if(map_base == MAP_FAILED){perror("mmap:");}val = *(volatile uint16_t *)(map_base + pgoffset);close(fd);munmap((void *)map_base, PAGE_SIZE);return val;}void Xil_Out8(uint64_t phyaddr, uint16_t val){int fd;volatile uint8_t *map_base;uint64_t base = phyaddr & PAGE_MASK;uint64_t pgoffset = phyaddr & (~PAGE_MASK);if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1){perror("open /dev/mem:");}map_base = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,fd, base);if(map_base == MAP_FAILED){perror("mmap:");}*(volatile uint8_t *)(map_base + pgoffset) = val; close(fd);munmap((void *)map_base, PAGE_SIZE);}int Xil_In8(uint64_t phyaddr){int fd;uint8_t val;volatile uint8_t *map_base;uint64_t base = phyaddr & PAGE_MASK;uint64_t pgoffset = phyaddr & (~PAGE_MASK);//open /dev/memif((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1){perror("open /dev/mem:");}//mmapmap_base = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,fd, base);if(map_base == MAP_FAILED){perror("mmap:");}val = *(volatile uint8_t *)(map_base + pgoffset);close(fd);munmap((void *)map_base, PAGE_SIZE);return val;}
//move.h#ifndef SMARTCARMOVE_H#define SMARTCARMOVE_H#include <stdio.h>#include <fcntl.h>#include <unistd.h>#include <string.h>#include <sys/time.h>#include <sys/stat.h>#include <sys/types.h>#include <syslog.h>#include <memory.h>static int fd;#define MODE (O_WRONLY | O_TRUNC)#define SECSIZE 65536#define XPAR_AXI_EMC_0_S_AXI_MEM0_BASEADDR 0x80000000#define WAIT_TICKS0xfffffffftypedef unsigned short u16;extern void flash_set16(unsigned int addrBase,unsigned int addrOffset,unsigned int value);extern int flash_get16(unsigned int addrBase,unsigned int addrOffset);extern int Erase_Flash(int sectorNum);extern int Write_Sector(int sectorNum,int offset,u16 *src_addr,int wr_num);extern int Read_Sector(int sectorNum,int rd_num,unsigned short *buf);#endif
#include "xil_io.h"#include "move.h"/**read and write phy mem* */void flash_set16(unsigned int addrBase,unsigned int addrOffset,unsigned int value){Xil_Out16(addrBase+2*addrOffset, value);//printf("flash set reg 0x%x value is 0x%x\n",addrBase+2*addrOffset,value);}int flash_get16(unsigned int addrBase,unsigned int addrOffset){int ans=0;ans=Xil_In16(addrBase+2*addrOffset);return ans;}int Erase_Flash(int sectorNum){unsigned short flag;int i=0;int val=0;unsigned short *base_addr;base_addr = (unsigned short*)(XPAR_AXI_EMC_0_S_AXI_MEM0_BASEADDR+SECSIZE*sectorNum*2);printf("erase start addr 0x%x\n",base_addr);flash_set16(base_addr,0x555,0x00AA);flash_set16(base_addr,0x2AA,0x0055);flash_set16(base_addr,0x555,0x0080);flash_set16(base_addr,0x555,0x00AA);flash_set16(base_addr,0x2AA,0x0055);flash_set16(base_addr,0,0x0030);val=flash_get16(base_addr,0);printf("base addr 0x%x val is 0x%x\n",base_addr,val);while((val&0x80)!=0x80){i++;if( i>=WAIT_TICKS){printf("addr %x Erase_Flash failed!\n",base_addr);flash_set16(base_addr,0x555,0x0090);flash_set16(base_addr,0x000,0x0000);return -1;}//flag = base_addr;val=flash_get16(base_addr,0);}flash_set16(base_addr,0x555,0x0090);flash_set16(base_addr,0x000,0x0000);printf("erase end addr %x\n",base_addr+SECSIZE);return 0; }int Write_Sector(int sectorNum,int offset,u16 *src_addr,int wr_num){int i,j;u16 *dst_addr;int val=0;int ans=0;dst_addr = (u16*)(XPAR_AXI_EMC_0_S_AXI_MEM0_BASEADDR+SECSIZE*sectorNum*2+offset);/* Unlock Bypass program */flash_set16(dst_addr,0x555,0x00AA);flash_set16(dst_addr,0x2AA,0x0055);printf("dst addr is 0x%x\n",dst_addr);for(i=0;i<wr_num;i++){flash_set16(dst_addr,0x555,0x0020);flash_set16(dst_addr,0x000,0x00A0);//printf("i is %d\n",i);val=src_addr[i];printf("val is 0x%x\n",val);flash_set16(dst_addr,i,val);ans=flash_get16(dst_addr,i);//printf("ans is 0x%x\n",ans);j=0;while( ans!= val){j++;if(j>=WAIT_TICKS){flash_set16(dst_addr,0x555,0x0090);flash_set16(dst_addr,0x000,0x0000);return -1;}ans=flash_get16(dst_addr,i);}}flash_set16(dst_addr,0x555,0x0090);flash_set16(dst_addr,0x000,0x0000);return 0; }int Read_Sector(int sectorNum,int rd_num,unsigned short *buf){unsigned short *sector_addr;int i;int val=0;if( rd_num <= 0){return -1;}printf("flash read start--sectorNum= %d rd_num= %d\n",sectorNum,rd_num);sector_addr = (u16*)(XPAR_AXI_EMC_0_S_AXI_MEM0_BASEADDR+SECSIZE*sectorNum*2);printf("sector addr is 0x%x\n",sector_addr);if( rd_num <= SECSIZE ){for(i=0;i<rd_num;i++){printf("val is 0x%x\n",flash_get16(sector_addr,0));val = flash_get16(sector_addr,0);*buf=val;buf++;sector_addr++;}}else{printf("error\n");}return 0;}int main(int argc, char *argv[]){//Erase_Flash(1);u16 dat[100];int i;Read_Sector(0,10,dat);for(i=0;i<10;i++){printf("0x%x\n",dat[i]);}/*for(i=0;i<100;i++){dat[i]=10+i;}Erase_Flash(0);Write_Sector(0,0,dat,10);*/return 0;}
3、 测试
这里没有驱动的概念，一切都放在用户态执行，编译产生flash应用程序，放到板子上执行程序进行测试即可。注意，写之前要擦除。
下图为写文件的测试，这里写了10个数：
写完以后再读
可以看到，读出来的和写入的值一样，测试通过。
4、 补充
关于/dev/mem可以看看下面这段代码，写的很详细，用户态直接访问物理地址，对于ZYNQ中PL部分的操作确实帮助极大。
/** devmem2.c: Simple program to read/write from/to any location in memory.** Copyright (C) 2000, Jan-Derk Bakker (J.D.Bakker@its.tudelft.nl)*** This software has been developed for the LART computing board* (http://www.lart.tudelft.nl/). The development has been sponsored by* the Mobile MultiMedia Communications (http://www.mmc.tudelft.nl/)* and Ubiquitous Communications (http://www.ubicom.tudelft.nl/)* projects.** The author can be reached at:** Jan-Derk Bakker* Information and Communication Theory Group* Faculty of Information Technology and Systems* Delft University of Technology* P.O. Box 5031* 2600 GA Delft* The Netherlands*** This program is free software; you can redistribute it and/or modify* it under the terms of the GNU General Public License as published by* the Free Software Foundation; either version 2 of the License, or* (at your option) any later version.** This program is distributed in the hope that it will be useful,* but WITHOUT ANY WARRANTY; without even the implied warranty of* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the* GNU General Public License for more details.* * You should have received a copy of the GNU General Public License* along with this program; if not, write to the Free Software* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA**/#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <string.h>#include <errno.h>#include <signal.h>#include <fcntl.h>#include <ctype.h>#include <termios.h>#include <sys/types.h>#include <sys/mman.h>#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \__LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0)#define MAP_SIZE 4096UL#define MAP_MASK (MAP_SIZE - 1)int main(int argc, char **argv) {int fd;void *map_base, *virt_addr; unsigned long read_result, writeval;off_t target;int access_type = 'w';if(argc < 2) {fprintf(stderr, "\nUsage:\t%s { address } [ type [ data ] ]\n""\taddress : memory address to act upon\n""\ttype : access operation type : [b]yte, [h]alfword, [w]ord\n""\tdata : data to be written\n\n",argv[0]);exit(1);}target = strtoul(argv[1], 0, 0);if(argc > 2)access_type = tolower(argv[2][0]);if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1) FATAL;printf("/dev/mem opened.\n"); fflush(stdout);/* Map one page */map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, target & ~MAP_MASK);if(map_base == (void *) -1) FATAL;printf("Memory mapped at address %p.\n", map_base); fflush(stdout);virt_addr = map_base + (target & MAP_MASK);switch(access_type) {case 'b':read_result = *((unsigned char *) virt_addr);break;case 'h':read_result = *((unsigned short *) virt_addr);break;case 'w':read_result = *((unsigned long *) virt_addr);break;default:fprintf(stderr, "Illegal data type '%c'.\n", access_type);exit(2);}printf("Value at address 0x%X (%p): 0x%X\n", target, virt_addr, read_result); fflush(stdout);if(argc > 3) {writeval = strtoul(argv[3], 0, 0);switch(access_type) {case 'b':*((unsigned char *) virt_addr) = writeval;read_result = *((unsigned char *) virt_addr);break;case 'h':*((unsigned short *) virt_addr) = writeval;read_result = *((unsigned short *) virt_addr);break;case 'w':*((unsigned long *) virt_addr) = writeval;read_result = *((unsigned long *) virt_addr);break;}printf("Written 0x%X; readback 0x%X\n", writeval, read_result); fflush(stdout);}if(munmap(map_base, MAP_SIZE) == -1) FATAL;close(fd);return 0;}
运行截图如下：
