mmapper_kern.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 150 行

/*
 * arch/um/drivers/mmapper_kern.c
 *
 * BRIEF MODULE DESCRIPTION
 *
 * Copyright (C) 2000 RidgeRun, Inc.
 * Author: RidgeRun, Inc.
 *         Greg Lonnon [e-mail] or [e-mail]
 *
 */
#include <linux/kdev_t.h>
#include <linux/time.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/module.h>
#include <linux/mm.h> 
#include <linux/slab.h>
#include <linux/init.h> 
#include <linux/smp_lock.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/pgtable.h>
#include "mem_user.h"
#include "user_util.h"
 
/* These are set in mmapper_init, which is called at boot time */
static unsigned long mmapper_size;
static unsigned long p_buf = 0;
static char *v_buf = NULL;

static ssize_t
mmapper_read(struct file *file, char *buf, size_t count, loff_t *ppos)
{
	if(*ppos > mmapper_size)
		return -EINVAL;

	if(count + *ppos > mmapper_size)
		count = count + *ppos - mmapper_size;

	if(count < 0)
		return -EINVAL;
 
	copy_to_user(buf,&v_buf[*ppos],count);
	
	return count;
}

static ssize_t
mmapper_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
	if(*ppos > mmapper_size)
		return -EINVAL;

	if(count + *ppos > mmapper_size)
		count = count + *ppos - mmapper_size;

	if(count < 0)
		return -EINVAL;

	copy_from_user(&v_buf[*ppos],buf,count);
	
	return count;
}

static int 
mmapper_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
	 unsigned long arg)
{
	return(-ENOIOCTLCMD);
}

static int 
mmapper_mmap(struct file *file, struct vm_area_struct * vma)
{
	int ret = -EINVAL;
	int size;

	lock_kernel();
	if (vma->vm_pgoff != 0)
		goto out;
	
	size = vma->vm_end - vma->vm_start;
	if(size > mmapper_size) return(-EFAULT);

	/* XXX A comment above remap_page_range says it should only be
	 * called when the mm semaphore is held
	 */
	if (remap_page_range(vma, vma->vm_start, p_buf, size, 
			     vma->vm_page_prot))
		goto out;
	ret = 0;
out:
	unlock_kernel();
	return ret;
}

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

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

static struct file_operations mmapper_fops = {
	.owner		= THIS_MODULE,
	.read		= mmapper_read,
	.write		= mmapper_write,
	.ioctl		= mmapper_ioctl,
	.mmap		= mmapper_mmap,
	.open		= mmapper_open,
	.release	= mmapper_release,
};

static int __init mmapper_init(void)
{
	printk(KERN_INFO "Mapper v0.1\n");

	v_buf = (char *) find_iomem("mmapper", &mmapper_size);
	if(mmapper_size == 0){
		printk(KERN_ERR "mmapper_init - find_iomem failed\n");
		return(0);
	}

	p_buf = __pa(v_buf);

	devfs_mk_cdev(MKDEV(30, 0), S_IFCHR|S_IRUGO|S_IWUGO, "mmapper");
	devfs_mk_symlink("mmapper0", "mmapper");
	return(0);
}

static void mmapper_exit(void)
{
}

module_init(mmapper_init);
module_exit(mmapper_exit);

MODULE_AUTHOR("Greg Lonnon <[e-mail]>");
MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");
/*
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */