/* * 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/smp_lock.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 time.c vs. this driver.) */ #include <linux/types.h> #include <linux/errno.h> #include <linux/miscdevice.h> #include <linux/slab.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 <asm/system.h> 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) { lock_kernel(); switch (origin) { case 0: /* nothing to do */ break; case 1: offset += file->f_pos; break; case 2: offset += NVRAM_BYTES; break; } unlock_kernel(); 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; int len; len = (NVRAM_BYTES - i) < count ? (NVRAM_BYTES - i) : count; if (copy_from_user(contents, buf, len)) return -EFAULT; spin_lock_irq(&rtc_lock); if (!__nvram_check_checksum()) goto checksum_err; for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++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 int nvram_ioctl(struct inode *inode, 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; 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); return 0; case NVRAM_SETCKS: /* just set checksum, contents unchanged (maybe useful after * checksum garbaged somehow...) */ if (!capable(CAP_SYS_ADMIN)) return -EACCES; spin_lock_irq(&rtc_lock); __nvram_set_checksum(); spin_unlock_irq(&rtc_lock); return 0; default: return -ENOTTY; } } static int nvram_open(struct inode *inode, struct file *file) { lock_kernel(); 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); unlock_kernel(); 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); unlock_kernel(); 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, .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);