hpi.c

ARM HPI程序。 用于ARM与DSP之间通信

/*
 * Copyright (C) 2004 Gexin TECH 
 *                     <[e-mail]>
 *
	 This file just for GX-ARM9-2410EP  

   Sat Feb 7 2004 Zhen-feng Zhao <[e-mail]>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/interrupt.h>	/* for in_interrupt */
#include <linux/timer.h>
#include <linux/init.h>
#include <linux/delay.h>	/* for udelay */
#include <linux/modversions.h>
#include <linux/version.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/segment.h>
#include <asm/uaccess.h>



#define hpi_MAJOR	98


devfs_handle_t  dev_handle;     /* register handle to store device fs */
static long ioremap_addr;

//1st byte is offset address, 2nd byte is data low 8 bit, 3rd byte is data high 8 bit
//4th byte is address low 8 bit, 5th byte is address high 8 bit
char write_buffer[3]={0,0,0};
char read_buffer[3]= {0,0,0};

ssize_t hpi_read (struct file * file ,char * buf, size_t count, loff_t * f_ops)
{
 unsigned int value;
 char ret=1;


	if (copy_from_user(read_buffer,buf,count)) //we need first byte as select 
	{	ret=-1;
		printk("%x\n",ret);	
		return ret;}
		
	value=inw(ioremap_addr+read_buffer[0]);

	read_buffer[1]=(char)(value & 0xff);
	read_buffer[2]=(char)(value >>8);

	copy_to_user(buf,read_buffer,count);
	
	 	
	return ret;
}	

void dsphpi_init(void)
{
        printk("dsphpi is initialed\n");
}

/*=========== HPI_DM642  Write =======================*/
ssize_t hpi_write (struct file * file ,const char * buf, size_t count, loff_t * f_ops)
{
 unsigned int value;
 char ret=1;

	if (copy_from_user(write_buffer,buf,count)) 
	{	ret=-1;
		printk("%x\n",ret);	
		return ret;}
	
	value=write_buffer[1]+(write_buffer[2]<<8);
	outw(value,(ioremap_addr+write_buffer[0]));
	return ret;
}	



/*=========== HPI_DM642 Ioctl =======================*/
ssize_t hpi_ioctl (struct inode * inode ,struct file * file,
	       	   unsigned int cmd, long data)
{
	printk("s3c2410: device ioctl operation!\n");	
	
}

/*============ HPI_DM642 device open ==============*/ 
ssize_t hpi_open (struct inode * inode ,struct file * file)
{
       // printk("open operation!\n");
        dsphpi_init();
	return 0;
}	

/*============ HPI_DM642 device close =============*/
ssize_t hpi_release (struct inode  * inode ,struct file * file)
{
//	outw(0x0000,ioremap_addr);
//	printk("s3c2410: device release operation!\n");	

	return 0;
}

struct file_operations hpi_ops ={
	
	open:		hpi_open,
	
	read:		hpi_read,
	
	write:		hpi_write,
	
	ioctl:		hpi_ioctl,
	
	release:	hpi_release,
};


static int __init HW_hpi_init(void)
{
//need to set 16 bit width of data bus.
    int ret = -ENODEV;
    int delay ;
	
	ret = devfs_register_chrdev(hpi_MAJOR, "hpi", &hpi_ops);  		

	if( ret < 0 ){
		printk (" s3c2410: init_module failed with %d\n", ret);	
		return ret;
	}
	else
		{
		printk(" S3c2410 HPI_DM642 register success!!!\n");
		}

	dev_handle = devfs_register( NULL, "hpi", DEVFS_FL_DEFAULT,
                        hpi_MAJOR, 0, S_IFCHR, &hpi_ops, NULL);

	ioremap_addr=ioremap(0x18000000,0xff);
	printk("remap address = %x\n",ioremap_addr);
	//!!!!!!!!!!!!!!
//***************************
	//outw(0,ioremap_addr);
	
//***************************

    return ret;
}


int __init s3c2410_hpi_init(void) {
    int  ret = -ENODEV;

    ret = HW_hpi_init();
    if (ret)
      return ret;
    return 0;
}
int init_module()
{
	s3c2410_hpi_init();
}
void cleanup_module()
{
        devfs_unregister_chrdev( hpi_MAJOR, "hpi" );
        devfs_unregister( dev_handle );
}