// SPDX-License-Identifier: GPL-2.0+ /* * CMOS/NV-RAM driver for Atari. Adapted from drivers/char/nvram.c. * Copyright (C) 1997 Roman Hodek * idea by and with help from Richard Jelinek * Portions copyright (c) 2001,2002 Sun Microsystems (thockin@sun.com) * Further contributions from Cesar Barros, Erik Gilling, Tim Hockin and * Wim Van Sebroeck. */ #include #include #include #include #include #include #include #include #include #include #include #define NVRAM_BYTES 50 /* 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. */ /* 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.) */ static unsigned char __nvram_read_byte(int i) { return CMOS_READ(NVRAM_FIRST_BYTE + i); } /* This races nicely with trying to read with checksum checking */ static void __nvram_write_byte(unsigned char c, int i) { CMOS_WRITE(c, NVRAM_FIRST_BYTE + i); } /* 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 static int __nvram_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 __nvram_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); } long atari_nvram_set_checksum(void) { spin_lock_irq(&rtc_lock); __nvram_set_checksum(); spin_unlock_irq(&rtc_lock); return 0; } long atari_nvram_initialize(void) { loff_t i; 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; } ssize_t atari_nvram_read(char *buf, size_t count, loff_t *ppos) { char *p = buf; loff_t i; spin_lock_irq(&rtc_lock); if (!__nvram_check_checksum()) { spin_unlock_irq(&rtc_lock); return -EIO; } for (i = *ppos; count > 0 && i < NVRAM_BYTES; --count, ++i, ++p) *p = __nvram_read_byte(i); spin_unlock_irq(&rtc_lock); *ppos = i; return p - buf; } ssize_t atari_nvram_write(char *buf, size_t count, loff_t *ppos) { char *p = buf; loff_t i; spin_lock_irq(&rtc_lock); if (!__nvram_check_checksum()) { spin_unlock_irq(&rtc_lock); return -EIO; } for (i = *ppos; count > 0 && i < NVRAM_BYTES; --count, ++i, ++p) __nvram_write_byte(*p, i); __nvram_set_checksum(); spin_unlock_irq(&rtc_lock); *ppos = i; return p - buf; } ssize_t atari_nvram_get_size(void) { return NVRAM_BYTES; } #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_nvram_proc_read(unsigned char *nvram, struct seq_file *seq, void *offset) { int checksum; int i; unsigned int vmode; spin_lock_irq(&rtc_lock); checksum = __nvram_check_checksum(); spin_unlock_irq(&rtc_lock); seq_printf(seq, "Checksum status : %svalid\n", checksum ? "" : "not "); seq_puts(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_puts(seq, "SCSI host ID : "); if (nvram[16] & 0x80) seq_printf(seq, "%d\n", nvram[16] & 7); else seq_puts(seq, "n/a\n"); if (!MACH_IS_FALCON) return; seq_puts(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_puts(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_puts(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_puts(seq, "Boot delay : "); if (nvram[10] == 0) seq_puts(seq, "default\n"); 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") : ""); } static int nvram_proc_read(struct seq_file *seq, void *offset) { unsigned char contents[NVRAM_BYTES]; int i; spin_lock_irq(&rtc_lock); for (i = 0; i < NVRAM_BYTES; ++i) contents[i] = __nvram_read_byte(i); spin_unlock_irq(&rtc_lock); atari_nvram_proc_read(contents, seq, offset); return 0; } static int __init atari_nvram_init(void) { if (!(MACH_IS_ATARI && ATARIHW_PRESENT(TT_CLK))) return -ENODEV; if (!proc_create_single("driver/nvram", 0, NULL, nvram_proc_read)) { pr_err("nvram: can't create /proc/driver/nvram\n"); return -ENOMEM; } return 0; } device_initcall(atari_nvram_init); #endif /* CONFIG_PROC_FS */