diff options
Diffstat (limited to 'drivers/char/nvram.c')
| -rw-r--r-- | drivers/char/nvram.c | 699 |
1 files changed, 699 insertions, 0 deletions
diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c new file mode 100644 index 000000000..25264d65e --- /dev/null +++ b/drivers/char/nvram.c @@ -0,0 +1,699 @@ +/* + * 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> +#include <linux/pagemap.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) +{ + return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE, + NVRAM_BYTES); +} + +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_add_proc_fs(void) +{ + if (!proc_create_single("driver/nvram", 0, NULL, nvram_proc_read)) + 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 const char * const 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 const char * const 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; + const char *name; +} boot_prefs[] = { + { 0x80, "TOS" }, + { 0x40, "ASV" }, + { 0x20, "NetBSD (?)" }, + { 0x10, "Linux" }, + { 0x00, "unspecified" } +}; + +static const char * const languages[] = { + "English (US)", + "German", + "French", + "English (UK)", + "Spanish", + "Italian", + "6 (undefined)", + "Swiss (French)", + "Swiss (German)" +}; + +static const char * const dateformat[] = { + "MM%cDD%cYY", + "DD%cMM%cYY", + "YY%cMM%cDD", + "YY%cDD%cMM", + "4 (undefined)", + "5 (undefined)", + "6 (undefined)", + "7 (undefined)" +}; + +static const char * const 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); |