- 根目录:
- drivers
- char
- nvram.c
/*
* CMOS/NV-RAM driver for Linux
*
* Copyright (C) 1997 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
* idea by and with help from Richard Jelinek <rj@suse.de>
* Portions copyright (c) 2001,2002 Sun Microsystems (thockin@sun.com)
*
* This driver allows you to access the contents of the non-volatile memory in
* the mc146818rtc.h real-time clock. This chip is built into all PCs and into
* many Atari machines. In the former it's called "CMOS-RAM", in the latter
* "NVRAM" (NV stands for non-volatile).
*
* The data are supplied as a (seekable) character device, /dev/nvram. The
* size of this file is dependent on the controller. The usual size is 114,
* the number of freely available bytes in the memory (i.e., not used by the
* RTC itself).
*
* Checksums over the NVRAM contents are managed by this driver. In case of a
* bad checksum, reads and writes return -EIO. The checksum can be initialized
* to a sane state either by ioctl(NVRAM_INIT) (clear whole NVRAM) or
* ioctl(NVRAM_SETCKS) (doesn't change contents, just makes checksum valid
* again; use with care!)
*
* This file also provides some functions for other parts of the kernel that
* want to access the NVRAM: nvram_{read,write,check_checksum,set_checksum}.
* Obviously this can be used only if this driver is always configured into
* the kernel and is not a module. Since the functions are used by some Atari
* drivers, this is the case on the Atari.
*
*
* 1.1 Cesar Barros: SMP locking fixes
* added changelog
* 1.2 Erik Gilling: Cobalt Networks support
* Tim Hockin: general cleanup, Cobalt support
* 1.3 Wim Van Sebroeck: convert PRINT_PROC to seq_file
*/
#define NVRAM_VERSION "1.3"
#include <linux/module.h>
#include <linux/nvram.h>
#define PC 1
#define ATARI 2
/* select machine configuration */
#if defined(CONFIG_ATARI)
# define MACH ATARI
#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) /* and ?? */
# define MACH PC
#else
# error Cannot build nvram driver for this machine configuration.
#endif
#if MACH == PC
/* RTC in a PC */
#define CHECK_DRIVER_INIT() 1
/* On PCs, the checksum is built only over bytes 2..31 */
#define PC_CKS_RANGE_START 2
#define PC_CKS_RANGE_END 31
#define PC_CKS_LOC 32
#define NVRAM_BYTES (128-NVRAM_FIRST_BYTE)
#define mach_check_checksum pc_check_checksum
#define mach_set_checksum pc_set_checksum
#define mach_proc_infos pc_proc_infos
#endif
#if MACH == ATARI
/* Special parameters for RTC in Atari machines */
#include <asm/atarihw.h>
#include <asm/atariints.h>
#define RTC_PORT(x) (TT_RTC_BAS + 2*(x))
#define CHECK_DRIVER_INIT() (MACH_IS_ATARI && ATARIHW_PRESENT(TT_CLK))
#define NVRAM_BYTES 50
/* On Ataris, the checksum is over all bytes except the checksum bytes
* themselves; these are at the very end */
#define ATARI_CKS_RANGE_START 0
#define ATARI_CKS_RANGE_END 47
#define ATARI_CKS_LOC 48
#define mach_check_checksum atari_check_checksum
#define mach_set_checksum atari_set_checksum
#define mach_proc_infos atari_proc_infos
#endif
/* Note that *all* calls to CMOS_READ and CMOS_WRITE must be done with
* rtc_lock held. Due to the index-port/data-port design of the RTC, we
* don't want two different things trying to get to it at once. (e.g. the
* periodic 11 min sync from kernel/time/ntp.c vs. this driver.)
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/mc146818rtc.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/mutex.h>
static DEFINE_MUTEX(nvram_mutex);
static DEFINE_SPINLOCK(nvram_state_lock);
static int nvram_open_cnt; /* #times opened */
static int nvram_open_mode; /* special open modes */
#define NVRAM_WRITE 1 /* opened for writing (exclusive) */
#define NVRAM_EXCL 2 /* opened with O_EXCL */
static int mach_check_checksum(void);
static void mach_set_checksum(void);
#ifdef CONFIG_PROC_FS
static void mach_proc_infos(unsigned char *contents, struct seq_file *seq,
void *offset);
#endif
/*
* These functions are provided to be called internally or by other parts of
* the kernel. It's up to the caller to ensure correct checksum before reading
* or after writing (needs to be done only once).
*
* It is worth noting that these functions all access bytes of general
* purpose memory in the NVRAM - that is to say, they all add the
* NVRAM_FIRST_BYTE offset. Pass them offsets into NVRAM as if you did not
* know about the RTC cruft.
*/
unsigned char __nvram_read_byte(int i)
{
return CMOS_READ(NVRAM_FIRST_BYTE + i);
}
EXPORT_SYMBOL(__nvram_read_byte);
unsigned char nvram_read_byte(int i)
{
unsigned long flags;
unsigned char c;
spin_lock_irqsave(&rtc_lock, flags);
c = __nvram_read_byte(i);
spin_unlock_irqrestore(&rtc_lock, flags);
return c;
}
EXPORT_SYMBOL(nvram_read_byte);
/* This races nicely with trying to read with checksum checking (nvram_read) */
void __nvram_write_byte(unsigned char c, int i)
{
CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
}
EXPORT_SYMBOL(__nvram_write_byte);
void nvram_write_byte(unsigned char c, int i)
{
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
__nvram_write_byte(c, i);
spin_unlock_irqrestore(&rtc_lock, flags);
}
EXPORT_SYMBOL(nvram_write_byte);
int __nvram_check_checksum(void)
{
return mach_check_checksum();
}
EXPORT_SYMBOL(__nvram_check_checksum);
int nvram_check_checksum(void)
{
unsigned long flags;
int rv;
spin_lock_irqsave(&rtc_lock, flags);
rv = __nvram_check_checksum();
spin_unlock_irqrestore(&rtc_lock, flags);
return rv;
}
EXPORT_SYMBOL(nvram_check_checksum);
static void __nvram_set_checksum(void)
{
mach_set_checksum();
}
#if 0
void nvram_set_checksum(void)
{
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
__nvram_set_checksum();
spin_unlock_irqrestore(&rtc_lock, flags);
}
#endif /* 0 */
/*
* The are the file operation function for user access to /dev/nvram
*/
static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
{
switch (origin) {
case 0:
/* nothing to do */
break;
case 1:
offset += file->f_pos;
break;
case 2:
offset += NVRAM_BYTES;
break;
default:
return -EINVAL;
}
return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
}
static ssize_t nvram_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
unsigned char contents[NVRAM_BYTES];
unsigned i = *ppos;
unsigned char *tmp;
spin_lock_irq(&rtc_lock);
if (!__nvram_check_checksum())
goto checksum_err;
for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
*tmp = __nvram_read_byte(i);
spin_unlock_irq(&rtc_lock);
if (copy_to_user(buf, contents, tmp - contents))
return -EFAULT;
*ppos = i;
return tmp - contents;
checksum_err:
spin_unlock_irq(&rtc_lock);
return -EIO;
}
static ssize_t nvram_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
unsigned char contents[NVRAM_BYTES];
unsigned i = *ppos;
unsigned char *tmp;
if (i >= NVRAM_BYTES)
return 0; /* Past EOF */
if (count > NVRAM_BYTES - i)
count = NVRAM_BYTES - i;
if (count > NVRAM_BYTES)
return -EFAULT; /* Can't happen, but prove it to gcc */
if (copy_from_user(contents, buf, count))
return -EFAULT;
spin_lock_irq(&rtc_lock);
if (!__nvram_check_checksum())
goto checksum_err;
for (tmp = contents; count--; ++i, ++tmp)
__nvram_write_byte(*tmp, i);
__nvram_set_checksum();
spin_unlock_irq(&rtc_lock);
*ppos = i;
return tmp - contents;
checksum_err:
spin_unlock_irq(&rtc_lock);
return -EIO;
}
static long nvram_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int i;
switch (cmd) {
case NVRAM_INIT:
/* initialize NVRAM contents and checksum */
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
mutex_lock(&nvram_mutex);
spin_lock_irq(&rtc_lock);
for (i = 0; i < NVRAM_BYTES; ++i)
__nvram_write_byte(0, i);
__nvram_set_checksum();
spin_unlock_irq(&rtc_lock);
mutex_unlock(&nvram_mutex);
return 0;
case NVRAM_SETCKS:
/* just set checksum, contents unchanged (maybe useful after
* checksum garbaged somehow...) */
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
mutex_lock(&nvram_mutex);
spin_lock_irq(&rtc_lock);
__nvram_set_checksum();
spin_unlock_irq(&rtc_lock);
mutex_unlock(&nvram_mutex);
return 0;
default:
return -ENOTTY;
}
}
static int nvram_open(struct inode *inode, struct file *file)
{
spin_lock(&nvram_state_lock);
if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
(nvram_open_mode & NVRAM_EXCL) ||
((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
spin_unlock(&nvram_state_lock);
return -EBUSY;
}
if (file->f_flags & O_EXCL)
nvram_open_mode |= NVRAM_EXCL;
if (file->f_mode & FMODE_WRITE)
nvram_open_mode |= NVRAM_WRITE;
nvram_open_cnt++;
spin_unlock(&nvram_state_lock);
return 0;
}
static int nvram_release(struct inode *inode, struct file *file)
{
spin_lock(&nvram_state_lock);
nvram_open_cnt--;
/* if only one instance is open, clear the EXCL bit */
if (nvram_open_mode & NVRAM_EXCL)
nvram_open_mode &= ~NVRAM_EXCL;
if (file->f_mode & FMODE_WRITE)
nvram_open_mode &= ~NVRAM_WRITE;
spin_unlock(&nvram_state_lock);
return 0;
}
#ifndef CONFIG_PROC_FS
static int nvram_add_proc_fs(void)
{
return 0;
}
#else
static int nvram_proc_read(struct seq_file *seq, void *offset)
{
unsigned char contents[NVRAM_BYTES];
int i = 0;
spin_lock_irq(&rtc_lock);
for (i = 0; i < NVRAM_BYTES; ++i)
contents[i] = __nvram_read_byte(i);
spin_unlock_irq(&rtc_lock);
mach_proc_infos(contents, seq, offset);
return 0;
}
static int nvram_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, nvram_proc_read, NULL);
}
static const struct file_operations nvram_proc_fops = {
.owner = THIS_MODULE,
.open = nvram_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int nvram_add_proc_fs(void)
{
if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
return -ENOMEM;
return 0;
}
#endif /* CONFIG_PROC_FS */
static const struct file_operations nvram_fops = {
.owner = THIS_MODULE,
.llseek = nvram_llseek,
.read = nvram_read,
.write = nvram_write,
.unlocked_ioctl = nvram_ioctl,
.open = nvram_open,
.release = nvram_release,
};
static struct miscdevice nvram_dev = {
NVRAM_MINOR,
"nvram",
&nvram_fops
};
static int __init nvram_init(void)
{
int ret;
/* First test whether the driver should init at all */
if (!CHECK_DRIVER_INIT())
return -ENODEV;
ret = misc_register(&nvram_dev);
if (ret) {
printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
NVRAM_MINOR);
goto out;
}
ret = nvram_add_proc_fs();
if (ret) {
printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
goto outmisc;
}
ret = 0;
printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
out:
return ret;
outmisc:
misc_deregister(&nvram_dev);
goto out;
}
static void __exit nvram_cleanup_module(void)
{
remove_proc_entry("driver/nvram", NULL);
misc_deregister(&nvram_dev);
}
module_init(nvram_init);
module_exit(nvram_cleanup_module);
/*
* Machine specific functions
*/
#if MACH == PC
static int pc_check_checksum(void)
{
int i;
unsigned short sum = 0;
unsigned short expect;
for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
sum += __nvram_read_byte(i);
expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
__nvram_read_byte(PC_CKS_LOC+1);
return (sum & 0xffff) == expect;
}
static void pc_set_checksum(void)
{
int i;
unsigned short sum = 0;
for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
sum += __nvram_read_byte(i);
__nvram_write_byte(sum >> 8, PC_CKS_LOC);
__nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
}
#ifdef CONFIG_PROC_FS
static char *floppy_types[] = {
"none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
"3.5'' 2.88M", "3.5'' 2.88M"
};
static char *gfx_types[] = {
"EGA, VGA, ... (with BIOS)",
"CGA (40 cols)",
"CGA (80 cols)",
"monochrome",
};
static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq,
void *offset)
{
int checksum;
int type;
spin_lock_irq(&rtc_lock);
checksum = __nvram_check_checksum();
spin_unlock_irq(&rtc_lock);
seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not ");
seq_printf(seq, "# floppies : %d\n",
(nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
seq_printf(seq, "Floppy 0 type : ");
type = nvram[2] >> 4;
if (type < ARRAY_SIZE(floppy_types))
seq_printf(seq, "%s\n", floppy_types[type]);
else
seq_printf(seq, "%d (unknown)\n", type);
seq_printf(seq, "Floppy 1 type : ");
type = nvram[2] & 0x0f;
if (type < ARRAY_SIZE(floppy_types))
seq_printf(seq, "%s\n", floppy_types[type]);
else
seq_printf(seq, "%d (unknown)\n", type);
seq_printf(seq, "HD 0 type : ");
type = nvram[4] >> 4;
if (type)
seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type);
else
seq_printf(seq, "none\n");
seq_printf(seq, "HD 1 type : ");
type = nvram[4] & 0x0f;
if (type)
seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type);
else
seq_printf(seq, "none\n");
seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
nvram[18] | (nvram[19] << 8),
nvram[20], nvram[25],
nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
nvram[39] | (nvram[40] << 8),
nvram[41], nvram[46],
nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n",
nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
seq_printf(seq, "Gfx adapter : %s\n",
gfx_types[(nvram[6] >> 4) & 3]);
seq_printf(seq, "FPU : %sinstalled\n",
(nvram[6] & 2) ? "" : "not ");
return;
}
#endif
#endif /* MACH == PC */
#if MACH == ATARI
static int atari_check_checksum(void)
{
int i;
unsigned char sum = 0;
for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
sum += __nvram_read_byte(i);
return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) &&
(__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
}
static void atari_set_checksum(void)
{
int i;
unsigned char sum = 0;
for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
sum += __nvram_read_byte(i);
__nvram_write_byte(~sum, ATARI_CKS_LOC);
__nvram_write_byte(sum, ATARI_CKS_LOC + 1);
}
#ifdef CONFIG_PROC_FS
static struct {
unsigned char val;
char *name;
} boot_prefs[] = {
{ 0x80, "TOS" },
{ 0x40, "ASV" },
{ 0x20, "NetBSD (?)" },
{ 0x10, "Linux" },
{ 0x00, "unspecified" }
};
static char *languages[] = {
"English (US)",
"German",
"French",
"English (UK)",
"Spanish",
"Italian",
"6 (undefined)",
"Swiss (French)",
"Swiss (German)"
};
static char *dateformat[] = {
"MM%cDD%cYY",
"DD%cMM%cYY",
"YY%cMM%cDD",
"YY%cDD%cMM",
"4 (undefined)",
"5 (undefined)",
"6 (undefined)",
"7 (undefined)"
};
static char *colors[] = {
"2", "4", "16", "256", "65536", "??", "??", "??"
};
static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq,
void *offset)
{
int checksum = nvram_check_checksum();
int i;
unsigned vmode;
seq_printf(seq, "Checksum status : %svalid\n", checksum ? "" : "not ");
seq_printf(seq, "Boot preference : ");
for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
if (nvram[1] == boot_prefs[i].val) {
seq_printf(seq, "%s\n", boot_prefs[i].name);
break;
}
}
if (i < 0)
seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
seq_printf(seq, "SCSI arbitration : %s\n",
(nvram[16] & 0x80) ? "on" : "off");
seq_printf(seq, "SCSI host ID : ");
if (nvram[16] & 0x80)
seq_printf(seq, "%d\n", nvram[16] & 7);
else
seq_printf(seq, "n/a\n");
/* the following entries are defined only for the Falcon */
if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
return;
seq_printf(seq, "OS language : ");
if (nvram[6] < ARRAY_SIZE(languages))
seq_printf(seq, "%s\n", languages[nvram[6]]);
else
seq_printf(seq, "%u (undefined)\n", nvram[6]);
seq_printf(seq, "Keyboard language: ");
if (nvram[7] < ARRAY_SIZE(languages))
seq_printf(seq, "%s\n", languages[nvram[7]]);
else
seq_printf(seq, "%u (undefined)\n", nvram[7]);
seq_printf(seq, "Date format : ");
seq_printf(seq, dateformat[nvram[8] & 7],
nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12);
seq_printf(seq, "Boot delay : ");
if (nvram[10] == 0)
seq_printf(seq, "default");
else
seq_printf(seq, "%ds%s\n", nvram[10],
nvram[10] < 8 ? ", no memory test" : "");
vmode = (nvram[14] << 8) | nvram[15];
seq_printf(seq,
"Video mode : %s colors, %d columns, %s %s monitor\n",
colors[vmode & 7],
vmode & 8 ? 80 : 40,
vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
seq_printf(seq, " %soverscan, compat. mode %s%s\n",
vmode & 64 ? "" : "no ",
vmode & 128 ? "on" : "off",
vmode & 256 ?
(vmode & 16 ? ", line doubling" : ", half screen") : "");
return;
}
#endif
#endif /* MACH == ATARI */
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(NVRAM_MINOR);