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发表于 2014-12-27 12:12 |只看该作者 |倒序浏览

您好，我最近在写Linux下的FPGA驱动程序，想要实现ARM与FPGA通信，实现二者之间的数据和命令传输，ARM芯片的arm920T，arm与fpga之间通过总线连接，fpga相当有挂接在arm片选nGCS2上的寄存器。对应的物理地址为0x10000000
，在内核空间，我已经通过测试了，通过ioremap内存映射，然后利用iowrite等函数可以对实现二者之间的数据传输。而现在我的问题是：在用户空间操作FPGA，我利用的是mmap函数，通过系统调用，在用户空间通过操作mmap返回的指针来实现通信，可是通过测试，发现数据没有写到FPGA中，应该是地址出现问题了，我有一个困惑：

如下是LDD3中一段
unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
unsigned long physical = simple_region_start + off;
...........
remap_pfn_range(vma, vma_>vm_start, physical, vsize, vma->vm_page_prot);

这里的remap_pfn_range中的第三个参数不是pfn页帧号吗？为啥是物理地址，对于这个参数我一直没弄清楚，如果我操作物理设备，那么这里的pfn 该怎么写，比如我的物理地址是physical 0x10000000  那么Pfn =physical>> PAGE_SHIFT ,是这样吗？
下面是我的驱动程序以及测试程序，希望大家帮位看看，谢谢啦

//s3c2440_fpga.c
#include <linux/delay.h>
#include <asm/io.h>
#include <asm/signal.h>
#include <asm-generic/siginfo.h>
#include <asm/irq.h>
#include <asm/unistd.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>
#include <asm/unistd.h>
#include <mach/regs-gpio.h>
#include <mach/regs-mem.h>
#include <mach/hardware.h>
#include <mach/regs-irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/irq.h>
#include <linux/types.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/ioport.h>
#include <linux/gpio.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/irqreturn.h>
#include <linux/irqnr.h>
#include <linux/hardirq.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include<linux/mm_types.h>
#include<linux/cdev.h>
#include<linux/io.h>
#include <linux/miscdevice.h>
#include <linux/pci.h>

#define DEVICE_NAME "FPGA"
#define FPGA_MAJOR 240
#define FPGA_ADDR 0x10000000 //物理地址0x10000000 ~  0x18000000

#define FPGA_NR_DEVS 1
#define FPGA_DEVS_SIZE 4096
#define FPGA_ADDR_SIZE  1024//申请IO内存的大小

#define GPACON (0x56000000)
#define BWSCON (0x48000000)
#define BANKCON2  (0x4800000C)

static volatile unsigned long *gpacon_addr;
static volatile unsigned long *bwscon_addr;
static volatile unsigned long *bankcon2_addr;
//static volatile unsigned long *FPGA_BASE;
static void __iomem *FPGA_BASE;

static unsigned long reg;
unsigned int ret = 0;
struct cdev cdev;

/************open***************/
static int fpga_open(struct inode *inode, struct file *file)
{
   printk("virt_addr = 0x%lx\n",(unsigned long)FPGA_BASE);
   printk("FPGA opened\n"

;
   return 0;
}

/************read***************/
static ssize_t fpga_read(struct file *file, char __user *buffer, size_t size, loff_t *ppos)
{
   reg=readl(FPGA_BASE+24);
   printk("0x%lx\n",reg);
   return ret;

}
/************write***************/
static ssize_t fpga_write(struct file *file,const char __user *buffer, size_t size, loff_t *ppos)
{

      iowrite16(0x456, FPGA_BASE+0x00000030);
   //writel(0x456, FPGA_BASE+12);
return ret;
}

static struct file_operations s3c2440_fpga_fops = {
   .owner = THIS_MODULE,
   .read  =fpga_read,
   .write =fpga_write,
   .open  =fpga_open,
};

static int __init s3c2440_fpga_init(void)
{
   int ret;
      struct resource *fpga_res;
   ret = register_chrdev(FPGA_MAJOR,DEVICE_NAME,& s3c2440_fpga_fops);
   if (ret < 0) {
      printk(DEVICE_NAME " can't register major number\n"

;
      return ret;
   }

/**************************** 申请I/O内存 *******************************/
   fpga_res=request_mem_region(FPGA_ADDR,FPGA_ADDR_SIZE,DEVICE_NAME);
      if(fpga_res==NULL)
      {
         printk("request io memery fail\n"

;
      ret =-EINVAL;
         goto fail_request_mem;
   }
//×××××××××××××××××××I/O内存映物理地址映射到虚拟地址××××××××××××××××××××××××××××××××//
   FPGA_BASE=(volatile unsigned long *)ioremap(FPGA_ADDR,FPGA_ADDR_SIZE);
   if(!FPGA_BASE)
   {
   printk("remap address fail\n"

;
   ret = -ENOMEM;
         goto fail_ioremap;

   }

//×××××××××××××××××××配置I/O寄存器设置时序和位宽以及片选nGCS2××××××××××××××××××××××××××××××//
      gpacon_addr=(volatile unsigned long *)ioremap_nocache(GPACON,0x0000004);
   bwscon_addr=(volatile unsigned long *)ioremap_nocache(BWSCON,0x0000004);
   bankcon2_addr=(volatile unsigned long *)ioremap_nocache(BANKCON2,0x0000004);

      writel( readl(gpacon_addr)|(0x01<<13),gpacon_addr);
   writel( (readl(bwscon_addr)&~(0xF<<

)|(0XE<<

,bwscon_addr);
   writel( (readl(bankcon2_addr)&~(0x8003)),bankcon2_addr);
   writel( (readl(bankcon2_addr)&~(0x03)),bankcon2_addr);

   /*cdev结构分配，注册，初始化，与linux内核之间传参数，涉内*/
   cdev_init(&cdev, &s3c2440_fpga_fops);
   cdev.owner = THIS_MODULE;
   cdev.ops = &s3c2440_fpga_fops;
   cdev_add(&cdev,MKDEV(FPGA_MAJOR,0), FPGA_NR_DEVS);//注册字符设备
      return 0;

      fail_request_mem:unregister_chrdev_region(MKDEV(FPGA_MAJOR,0),FPGA_NR_DEVS);
                        return ret;
      fail_ioremap: release_mem_region(FPGA_ADDR,FPGA_ADDR_SIZE); //释放IO内存
                  unregister_chrdev_region(MKDEV(FPGA_MAJOR,0), FPGA_NR_DEVS);
                  return ret;
}

static void __exit s3c2440_fpga_exit(void)
{
unregister_chrdev(FPGA_MAJOR, DEVICE_NAME);
iounmap(FPGA_BASE);
iounmap(gpacon_addr);
iounmap(bwscon_addr);
iounmap(bankcon2_addr);
release_mem_region(FPGA_ADDR,FPGA_ADDR_SIZE); //释放IO内存
      cdev_del(&cdev);

}

MODULE_LICENSE("GPL"

;
module_init(s3c2440_fpga_init);
module_exit(s3c2440_fpga_exit);

//fpga_test.c

#include<fcntl.h>
#include<unistd.h>
#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<sys/mman.h>
#include<string.h>
#define FPGA_Address 0x10000000
#define SIZE (100)
typedef struct
{
  unsigned long r_MemUnit1[65536];  //32位无符号数据    Total Size:1MB Address Space
}MEMUNIT;
int main(void)
{
      int fd,i;
      MEMUNIT record, *addrs;
      char *buf="butterfly!";
      fd = open("/dev/FPGA",O_RDWR);
      if(fd == -1)
      {
         printf("Error!!\n"

;
         exit(-1);
      }
   // addrs =( MEMUNIT *)mmap(NULL,SIZE* sizeof(record),PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);
      addrs =( MEMUNIT *)mmap(NULL,4096,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);
      if(addrs==MAP_FAILED)
      {
      printf("mmap error!!!\n"

;
      exit(-1);
      }
      addrs->r_MemUnit1[12]=12;
      msync((void *)addrs,4096, MS_ASYNC);
      printf("addrs[12]:0x%lx\n",addrs);
      printf("addrs[12]:0x%lx\n",addrs->r_MemUnit1[0]);
      printf("addrs[12]:0x%lx\n",addrs->r_MemUnit1[1]);
      printf("addrs[12]:0x%lx\n",addrs->r_MemUnit1[2]);
      printf("addrs[12]:0x%x\n",addrs->r_MemUnit1[12]);
   /*  while(1)
      {
      read(fd,buf,3);
      }*/
      munmap((void *)addrs,4096);
      close(fd);
      exit(0);

}

linux字符设备驱动