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* linux/drivers/char/mem.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/config.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/tty.h>
#include <linux/miscdevice.h>
#include <linux/tpqic02.h>
#include <linux/ftape.h>
#include <linux/malloc.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/random.h>
#include <asm/segment.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#ifdef CONFIG_SOUND
void soundcard_init(void);
#endif
#ifdef CONFIG_ISDN
void isdn_init(void);
#endif
#ifdef CONFIG_PCWATCHDOG
void pcwatchdog_init(void);
#endif
static int read_ram(struct inode * inode, struct file * file, char * buf, int count)
{
return -EIO;
}
static int write_ram(struct inode * inode, struct file * file, const char * buf, int count)
{
return -EIO;
}
static int read_mem(struct inode * inode, struct file * file, char * buf, int count)
{
unsigned long p = file->f_pos;
int read;
p += PAGE_OFFSET;
if (count < 0)
return -EINVAL;
if (MAP_NR(p) >= MAP_NR(high_memory))
return 0;
if (count > high_memory - p)
count = high_memory - p;
read = 0;
#if defined(__i386__) || defined(__sparc__) /* we don't have page 0 mapped on x86/sparc.. */
while (p < PAGE_OFFSET + PAGE_SIZE && count > 0) {
put_user(0,buf);
buf++;
p++;
count--;
read++;
}
#endif
memcpy_tofs(buf, (void *) p, count);
read += count;
file->f_pos += read;
return read;
}
static int write_mem(struct inode * inode, struct file * file, const char * buf, int count)
{
unsigned long p = file->f_pos;
int written;
p += PAGE_OFFSET;
if (count < 0)
return -EINVAL;
if (MAP_NR(p) >= MAP_NR(high_memory))
return 0;
if (count > high_memory - p)
count = high_memory - p;
written = 0;
#if defined(__i386__) || defined(__sparc__) /* we don't have page 0 mapped on x86/sparc.. */
while (PAGE_OFFSET + p < PAGE_SIZE && count > 0) {
/* Hmm. Do something? */
buf++;
p++;
count--;
written++;
}
#endif
memcpy_fromfs((void *) p, buf, count);
written += count;
file->f_pos += written;
return count;
}
static int mmap_mem(struct inode * inode, struct file * file, struct vm_area_struct * vma)
{
if (vma->vm_offset & ~PAGE_MASK)
return -ENXIO;
#if defined(__i386__)
/*
* hmm.. This disables high-memory caching, as the XFree86 team
* wondered about that at one time.
* The surround logic should disable caching for the high device
* addresses anyway, but right now this seems still needed.
*/
if (x86 > 3 && vma->vm_offset >= high_memory)
pgprot_val(vma->vm_page_prot) |= _PAGE_PCD;
#endif
if (remap_page_range(vma->vm_start, vma->vm_offset, vma->vm_end - vma->vm_start, vma->vm_page_prot))
return -EAGAIN;
vma->vm_inode = inode;
inode->i_count++;
return 0;
}
static int read_kmem(struct inode *inode, struct file *file, char *buf, int count)
{
int read1, read2;
read1 = read_mem(inode, file, buf, count);
if (read1 < 0)
return read1;
read2 = vread(buf + read1, (char *) ((unsigned long) file->f_pos), count - read1);
if (read2 < 0)
return read2;
file->f_pos += read2;
return read1 + read2;
}
static int read_port(struct inode * inode, struct file * file,char * buf, int count)
{
unsigned int i = file->f_pos;
char * tmp = buf;
while (count-- > 0 && i < 65536) {
put_user(inb(i),tmp);
i++;
tmp++;
}
file->f_pos = i;
return tmp-buf;
}
static int write_port(struct inode * inode, struct file * file, const char * buf, int count)
{
unsigned int i = file->f_pos;
const char * tmp = buf;
while (count-- > 0 && i < 65536) {
outb(get_user(tmp),i);
i++;
tmp++;
}
file->f_pos = i;
return tmp-buf;
}
static int read_null(struct inode * node, struct file * file, char * buf, int count)
{
return 0;
}
static int write_null(struct inode * inode, struct file * file, const char * buf, int count)
{
return count;
}
static int read_zero(struct inode * node, struct file * file, char * buf, int count)
{
int left;
for (left = count; left > 0; left--) {
put_user(0,buf);
buf++;
if (need_resched)
schedule();
}
return count;
}
static int mmap_zero(struct inode * inode, struct file * file, struct vm_area_struct * vma)
{
if (vma->vm_flags & VM_SHARED)
return -EINVAL;
if (zeromap_page_range(vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
return -EAGAIN;
return 0;
}
static int write_full(struct inode * inode, struct file * file, const char * buf, int count)
{
return -ENOSPC;
}
/*
* Special lseek() function for /dev/null and /dev/zero. Most notably, you can fopen()
* both devices with "a" now. This was previously impossible. SRB.
*/
static int null_lseek(struct inode * inode, struct file * file, off_t offset, int orig)
{
return file->f_pos=0;
}
/*
* The memory devices use the full 32/64 bits of the offset, and so we cannot
* check against negative addresses: they are ok. The return value is weird,
* though, in that case (0).
*
* also note that seeking relative to the "end of file" isn't supported:
* it has no meaning, so it returns -EINVAL.
*/
static int memory_lseek(struct inode * inode, struct file * file, off_t offset, int orig)
{
switch (orig) {
case 0:
file->f_pos = offset;
return file->f_pos;
case 1:
file->f_pos += offset;
return file->f_pos;
default:
return -EINVAL;
}
if (file->f_pos < 0)
return 0;
return file->f_pos;
}
#define write_kmem write_mem
#define mmap_kmem mmap_mem
#define zero_lseek null_lseek
#define full_lseek null_lseek
#define write_zero write_null
#define read_full read_null
static struct file_operations ram_fops = {
memory_lseek,
read_ram,
write_ram,
NULL, /* ram_readdir */
NULL, /* ram_select */
NULL, /* ram_ioctl */
NULL, /* ram_mmap */
NULL, /* no special open code */
NULL, /* no special release code */
NULL /* fsync */
};
static struct file_operations mem_fops = {
memory_lseek,
read_mem,
write_mem,
NULL, /* mem_readdir */
NULL, /* mem_select */
NULL, /* mem_ioctl */
mmap_mem,
NULL, /* no special open code */
NULL, /* no special release code */
NULL /* fsync */
};
static struct file_operations kmem_fops = {
memory_lseek,
read_kmem,
write_kmem,
NULL, /* kmem_readdir */
NULL, /* kmem_select */
NULL, /* kmem_ioctl */
mmap_kmem,
NULL, /* no special open code */
NULL, /* no special release code */
NULL /* fsync */
};
static struct file_operations null_fops = {
null_lseek,
read_null,
write_null,
NULL, /* null_readdir */
NULL, /* null_select */
NULL, /* null_ioctl */
NULL, /* null_mmap */
NULL, /* no special open code */
NULL, /* no special release code */
NULL /* fsync */
};
static struct file_operations port_fops = {
memory_lseek,
read_port,
write_port,
NULL, /* port_readdir */
NULL, /* port_select */
NULL, /* port_ioctl */
NULL, /* port_mmap */
NULL, /* no special open code */
NULL, /* no special release code */
NULL /* fsync */
};
static struct file_operations zero_fops = {
zero_lseek,
read_zero,
write_zero,
NULL, /* zero_readdir */
NULL, /* zero_select */
NULL, /* zero_ioctl */
mmap_zero,
NULL, /* no special open code */
NULL /* no special release code */
};
static struct file_operations full_fops = {
full_lseek,
read_full,
write_full,
NULL, /* full_readdir */
NULL, /* full_select */
NULL, /* full_ioctl */
NULL, /* full_mmap */
NULL, /* no special open code */
NULL /* no special release code */
};
static int memory_open(struct inode * inode, struct file * filp)
{
switch (MINOR(inode->i_rdev)) {
case 0:
filp->f_op = &ram_fops;
break;
case 1:
filp->f_op = &mem_fops;
break;
case 2:
filp->f_op = &kmem_fops;
break;
case 3:
filp->f_op = &null_fops;
break;
case 4:
filp->f_op = &port_fops;
break;
case 5:
filp->f_op = &zero_fops;
break;
case 7:
filp->f_op = &full_fops;
break;
case 8:
filp->f_op = &random_fops;
break;
case 9:
filp->f_op = &urandom_fops;
break;
default:
return -ENXIO;
}
if (filp->f_op && filp->f_op->open)
return filp->f_op->open(inode,filp);
return 0;
}
static struct file_operations memory_fops = {
NULL, /* lseek */
NULL, /* read */
NULL, /* write */
NULL, /* readdir */
NULL, /* select */
NULL, /* ioctl */
NULL, /* mmap */
memory_open, /* just a selector for the real open */
NULL, /* release */
NULL /* fsync */
};
int chr_dev_init(void)
{
if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
printk("unable to get major %d for memory devs\n", MEM_MAJOR);
rand_initialize();
tty_init();
#ifdef CONFIG_PRINTER
lp_init();
#endif
#if defined (CONFIG_BUSMOUSE) || defined(CONFIG_UMISC) || \
defined (CONFIG_PSMOUSE) || defined (CONFIG_MS_BUSMOUSE) || \
defined (CONFIG_ATIXL_BUSMOUSE) || defined(CONFIG_SOFT_WATCHDOG) || \
defined (CONFIG_PCWATCHDOG) || \
defined (CONFIG_APM) || defined (CONFIG_RTC) || defined (CONFIG_SUN_MOUSE)
misc_init();
#endif
#ifdef CONFIG_SOUND
soundcard_init();
#endif
#if CONFIG_QIC02_TAPE
qic02_tape_init();
#endif
#if CONFIG_ISDN
isdn_init();
#endif
#ifdef CONFIG_FTAPE
ftape_init();
#endif
return 0;
}
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