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/*
* Simple - REALLY simple memory mapping demonstration.
* $Id: mmap.c,v 1.1 2007-12-21 10:28:22 davidhsu Exp $
*/
#ifndef __KERNEL__
# define __KERNEL__
#endif
#ifndef NO_MM
#include <linux/config.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/kernel.h> /* printk() */
#include <linux/slab.h> /* kmalloc() */
#include <linux/fs.h> /* everything... */
#include <linux/errno.h> /* error codes */
#include <linux/types.h> /* size_t */
#include <linux/init.h> /* module_init */
#include <asm/page.h>
#include "common/rtl_glue.h" /*rtlglue_printf()*/
#define CONFIG_DEFAULTS_KERNEL_2_6 1
static int simple_major = 254;
#ifdef CONFIG_RTL865X_MODULE_ROMEDRV
#else
#ifdef CONFIG_DEFAULTS_KERNEL_2_6
module_param(simple_major, int, S_IRUGO);
#else
MODULE_PARM(simple_major, "i");
#endif
MODULE_AUTHOR("Jonathan Corbet");
#endif
/*
* Forwards for our methods.
*/
int simple_open (struct inode *inode, struct file *filp);
int simple_release(struct inode *inode, struct file *filp);
int simple_remap_mmap(struct file *filp, struct vm_area_struct *vma);
int simple_nopage_mmap(struct file *filp, struct vm_area_struct *vma);
/*
* Our various sub-devices.
*/
/* Device 0 uses remap_page_range */
struct file_operations simple_remap_ops = {
open: simple_open,
release: simple_release,
mmap: simple_remap_mmap,
};
/* Device 1 uses nopage */
struct file_operations simple_nopage_ops = {
open: simple_open,
release: simple_release,
mmap: simple_nopage_mmap,
};
#define MAX_SIMPLE_DEV 2
struct file_operations *simple_fops[MAX_SIMPLE_DEV] = {
&simple_remap_ops,
&simple_nopage_ops,
};
/*
* Open the device; all we have to do here is to up the usage count and
* set the right fops.
*/
int simple_open (struct inode *inode, struct file *filp)
{
unsigned int dev = MINOR(inode->i_rdev);
if (dev >= MAX_SIMPLE_DEV)
return -ENODEV;
filp->f_op = simple_fops[dev];
#ifdef CONFIG_DEFAULTS_KERNEL_2_6
#else
MOD_INC_USE_COUNT;
#endif
return 0;
}
/*
* Closing is even simpler.
*/
int simple_release(struct inode *inode, struct file *filp)
{
#ifdef CONFIG_DEFAULTS_KERNEL_2_6
#else
MOD_DEC_USE_COUNT;
#endif
return 0;
}
/*
* Common VMA ops.
*/
void simple_vma_open(struct vm_area_struct *vma)
#ifdef CONFIG_DEFAULTS_KERNEL_2_6
{}
#else
{ MOD_INC_USE_COUNT; }
#endif
void simple_vma_close(struct vm_area_struct *vma)
#ifdef CONFIG_DEFAULTS_KERNEL_2_6
{}
#else
{ MOD_DEC_USE_COUNT; }
#endif
/*
* The remap_pfn_range version of mmap.
*/
static struct vm_operations_struct simple_remap_vm_ops = {
open: simple_vma_open,
close: simple_vma_close,
};
int simple_remap_mmap(struct file *filp, struct vm_area_struct *vma)
{
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
if (offset >= __pa(high_memory) || (filp->f_flags & O_SYNC))
vma->vm_flags |= VM_IO;
vma->vm_flags |= VM_RESERVED;
#ifdef CONFIG_DEFAULTS_KERNEL_2_6
if (remap_pfn_range(vma, vma->vm_start, offset, vma->vm_end-vma->vm_start, vma->vm_page_prot))
#else
if (remap_page_range(vma->vm_start, offset, vma->vm_end-vma->vm_start, vma->vm_page_prot))
#endif
return -EAGAIN;
vma->vm_ops = &simple_remap_vm_ops;
simple_vma_open(vma);
return 0;
}
/*
* The nopage version.
*/
#ifdef CONFIG_DEFAULTS_KERNEL_2_6
struct page *simple_vma_nopage(struct vm_area_struct *vma, unsigned long address, int* write_access)
#else
struct page *simple_vma_nopage(struct vm_area_struct *vma, unsigned long address, int write_access)
#endif
{
struct page *pageptr;
unsigned long physaddr = address - vma->vm_start +
(vma->vm_pgoff << PAGE_SHIFT);
pageptr = virt_to_page(__va(physaddr));
get_page(pageptr);
return pageptr;
}
static struct vm_operations_struct simple_nopage_vm_ops = {
open: simple_vma_open,
close: simple_vma_close,
nopage: simple_vma_nopage,
};
int simple_nopage_mmap(struct file *filp, struct vm_area_struct *vma)
{
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
if (offset >= __pa(high_memory) || (filp->f_flags & O_SYNC))
vma->vm_flags |= VM_IO;
vma->vm_flags |= VM_RESERVED;
vma->vm_ops = &simple_nopage_vm_ops;
simple_vma_open(vma);
return 0;
}
/*
* Module housekeeping.
*/
#ifdef CONFIG_RTL865X_MODULE_ROMEDRV
int simple_init(void)
#else
static int simple_init(void)
#endif
{
int result;
result = register_chrdev(simple_major, "simple", &simple_remap_ops);
if (result < 0)
{
rtlglue_printf("simple: unable to get major %d\n", simple_major);
return result;
}
if (simple_major == 0)
simple_major = result;
return 0;
}
#ifdef CONFIG_RTL865X_MODULE_ROMEDRV
void simple_cleanup(void)
#else
static void simple_cleanup(void)
#endif
{
unregister_chrdev(simple_major, "simple");
}
#ifdef CONFIG_RTL865X_MODULE_ROMEDRV
#else
module_init(simple_init);
module_exit(simple_cleanup);
#endif
#endif
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