OpenRisc入门（11）-编写ipcore 的linux driver，然后run helloworld

引言

我觉得ORPSoC的关键在于‘P’，即programmable。SoC的有优势就在于只要是满足总线interface的ip，可以实现plug & work。

所以一旦完成前面的工作之后，添加属于自己的ip core到ORPSoC的wishbone总线上，并编写它对应的驱动就成为非常关键的一步。

本小节就做一个简单的例子，来说明需要完成的工作步骤及其中遇到的问题和对应的解决方法。

11.1 编写wishbone为interface的ip core（ip_mkg）

1》这一步请参考：

http://blog.csdn.net/rill_zhen/article/details/8659788

2》将其中的my_slave_module链接到ORPSoC的wishbone上。

11.2 编写linux下的driver module

代码及makefile如下：

1》ip_mkg.c

/*
*
* rill mkg driver
*
*/
#include <linux/vmalloc.h>
#include <linux/slab.h>  

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <asm/uaccess.h> /* get_user and put_user */
//#include <linux/clk.h>
//#include <linux/ioport.h>
#include <asm/io.h> /*ioremap*/
#include <linux/platform_device.h> /*cleanup_module*/  

#include "ip_mkg.h"  

void    __iomem     *g_mkg_mem_base = NULL;  

static int device_open(struct inode *inode, struct file *file)
{
    g_mkg_mem_base = ioremap(MKG_MEM_BASE,MKG_MEM_LEN);
    if(NULL == g_mkg_mem_base)
    {
        printk(KERN_ERR "mkg open ioremap error!\n");
        return -1;
    }
    else
    {
        printk("mkg ioremap addr:%d!\n",(int)g_mkg_mem_base);
    }  

    return 0;
}  

static int device_release(struct inode *inode, struct file *file)
{
    return 0;
}  

static ssize_t device_read(struct file *filp, char *buffer, size_t length, loff_t *offset)
{
    return 0;
}  

static ssize_t device_write(struct file *filp, const char *buffer, size_t count, loff_t *offset)
{
   return 0;
}  

long device_ioctl(struct file *file, unsigned int ioctl_num, unsigned long ioctl_param)
{
   int ret_val = 0;
   unsigned int ret = 0;
   struct reg_data *new_regs;  

   switch(ioctl_num)
   {
      case IOCTL_REG_SET:
      {
         new_regs = (struct reg_data*)kmalloc(sizeof(struct reg_data), GFP_KERNEL);
         if((ret_val = copy_from_user(new_regs, (struct reg_data*)ioctl_param, sizeof(struct reg_data))) != 0)
            {
                kfree(new_regs);
                printk(KERN_ERR " error copy line_datafrom user.\n");
                return -1;
            }  

            iowrite16(new_regs->value,g_mkg_mem_base+new_regs->addr);
         kfree(new_regs);
     }
     break;  

    case IOCTL_REG_GET:
    {
     new_regs = (struct reg_data*)kmalloc(sizeof(struct reg_data), GFP_KERNEL);
     if((ret_val = copy_from_user(new_regs, (struct reg_data*)ioctl_param, sizeof(struct reg_data))) != 0)
        {
            kfree(new_regs);
            printk(KERN_ERR " error copy line_datafrom user.\n");
            return -1;
        }  

        ret = ioread16(g_mkg_mem_base+new_regs->addr);
        kfree(new_regs);
        return ret;
    }
    break;  

   }  

  return -1;
}  

struct file_operations our_file_ops = {
  .unlocked_ioctl = device_ioctl,
  .read = device_read,
  .write = device_write,
  .open = device_open,
  .release = device_release,
  .owner = THIS_MODULE,
};  

int init_module()
{
    int ret_val;
    int ret;
    void __iomem *ret_from_request;  

    //=== Allocate character device
    ret_val = register_chrdev(MAJOR_NUM, DEVICE_NAME, &our_file_ops);
    if (ret_val < 0)
    {
        printk(KERN_ALERT " device %s failed(%d)\n", DEVICE_NAME, ret_val);
        return ret_val;
    }  

    ret = check_mem_region(MKG_MEM_BASE, MKG_MEM_LEN);
    if (ret < 0)
    {
        printk(KERN_ERR "mkg check_mem_region bussy error!\n");
        return -1;
    }  

    ret_from_request = request_mem_region(MKG_MEM_BASE, MKG_MEM_LEN, "ip_mkg");  

    //===ioremap mkg registers  

    g_mkg_mem_base = ioremap(MKG_MEM_BASE,MKG_MEM_LEN);
    if(NULL == g_mkg_mem_base)
    {
        printk(KERN_ERR "mkg ioremap error!\n");
        return -1;
    }
    else
    {
        ;//printk("mkg ioremap addr:%d!\n",g_mkg_mem_base);
    }  

    printk("mkg module init done!\n");  

    return 0;
}  

void cleanup_module()
{
    release_mem_region(MKG_MEM_BASE, MKG_MEM_LEN);  

    unregister_chrdev(MAJOR_NUM, DEVICE_NAME);
}  

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rill zhen:rillzhen@gmail.com");

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