| /* |
| * This file is part of the libpayload project. |
| * |
| * Copyright (C) 2008 Uwe Hermann <uwe@hermann-uwe.de> |
| * Copyright (C) 2017 Patrick Rudolph <siro@das-labor.org> |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| /* |
| * Datasheet: |
| * - Name: MC146818: Real-time Clock Plus RAM (RTC) |
| * - PDF: http://www.freescale.com/files/microcontrollers/doc/data_sheet/MC146818.pdf |
| * - Order number: MC146818/D |
| */ |
| |
| /* |
| * See also: |
| * http://bochs.sourceforge.net/techspec/CMOS-reference.txt |
| * http://www.bioscentral.com/misc/cmosmap.htm |
| */ |
| #include <libpayload-config.h> |
| #include <libpayload.h> |
| |
| |
| /** |
| * PCs can have either 64 (very old ones), 128, or 256 bytes of CMOS RAM. |
| * |
| * Usually you access the lower 128 CMOS bytes via I/O port 0x70/0x71. |
| * For more recent chipsets with 256 bytes, you have to access the upper |
| * 128 bytes (128-255) using two different registers, usually 0x72/0x73. |
| * |
| * On some chipsets this can be different, though. The VIA VT8237R for example |
| * only recognizes the ports 0x74/0x75 for accessing the high 128 CMOS bytes |
| * (as seems to be the case for multiple VIA chipsets). |
| * |
| * It's very chipset-specific if and how the upper 128 bytes are enabled at |
| * all, but this work should be done in coreboot anyway. Libpayload assumes |
| * that coreboot has properly enabled access to the upper 128 bytes and |
| * doesn't try to do this on its own. |
| */ |
| #define RTC_PORT_STANDARD 0x70 |
| #if CONFIG(LP_RTC_PORT_EXTENDED_VIA) |
| #define RTC_PORT_EXTENDED 0x74 |
| #else |
| #define RTC_PORT_EXTENDED 0x72 |
| #endif |
| |
| /** |
| * Read a byte from the specified NVRAM address. |
| * |
| * @param addr The NVRAM address to read a byte from. |
| * @return The byte at the given NVRAM address. |
| */ |
| u8 nvram_read(u8 addr) |
| { |
| u16 rtc_port = addr < 128 ? RTC_PORT_STANDARD : RTC_PORT_EXTENDED; |
| |
| outb(addr, rtc_port); |
| return inb(rtc_port + 1); |
| } |
| |
| /** |
| * Write a byte to the specified NVRAM address. |
| * |
| * @param val The byte to write to NVRAM. |
| * @param addr The NVRAM address to write to. |
| */ |
| void nvram_write(u8 val, u8 addr) |
| { |
| u16 rtc_port = addr < 128 ? RTC_PORT_STANDARD : RTC_PORT_EXTENDED; |
| |
| outb(addr, rtc_port); |
| outb(val, rtc_port + 1); |
| } |
| |
| /** |
| * Return 1 if the NVRAM is currently updating and a 0 otherwise |
| * @return A 1 if the NVRAM is updating and 0 otherwise |
| */ |
| |
| int nvram_updating(void) |
| { |
| return (nvram_read(NVRAM_RTC_FREQ_SELECT) & NVRAM_RTC_UIP) ? 1 : 0; |
| } |
| |
| /** |
| * Get the current time and date from the RTC |
| * |
| * @param time A pointer to a broken-down time structure |
| */ |
| void rtc_read_clock(struct tm *time) |
| { |
| u16 timeout = 10000; |
| u8 statusB; |
| u8 reg8; |
| |
| memset(time, 0, sizeof(*time)); |
| |
| while (nvram_updating()) |
| if (!timeout--) |
| return; |
| |
| statusB = nvram_read(NVRAM_RTC_STATUSB); |
| |
| if (!(statusB & NVRAM_RTC_FORMAT_BINARY)) { |
| time->tm_mon = bcd2dec(nvram_read(NVRAM_RTC_MONTH)) - 1; |
| time->tm_sec = bcd2dec(nvram_read(NVRAM_RTC_SECONDS)); |
| time->tm_min = bcd2dec(nvram_read(NVRAM_RTC_MINUTES)); |
| time->tm_mday = bcd2dec(nvram_read(NVRAM_RTC_DAY)); |
| |
| if (!(statusB & NVRAM_RTC_FORMAT_24HOUR)) { |
| reg8 = nvram_read(NVRAM_RTC_HOURS); |
| time->tm_hour = bcd2dec(reg8 & 0x7f); |
| time->tm_hour += (reg8 & 0x80) ? 12 : 0; |
| time->tm_hour %= 24; |
| } else { |
| time->tm_hour = bcd2dec(nvram_read(NVRAM_RTC_HOURS)); |
| } |
| time->tm_year = bcd2dec(nvram_read(NVRAM_RTC_YEAR)); |
| } else { |
| time->tm_mon = nvram_read(NVRAM_RTC_MONTH) - 1; |
| time->tm_sec = nvram_read(NVRAM_RTC_SECONDS); |
| time->tm_min = nvram_read(NVRAM_RTC_MINUTES); |
| time->tm_mday = nvram_read(NVRAM_RTC_DAY); |
| if (!(statusB & NVRAM_RTC_FORMAT_24HOUR)) { |
| reg8 = nvram_read(NVRAM_RTC_HOURS); |
| time->tm_hour = reg8 & 0x7f; |
| time->tm_hour += (reg8 & 0x80) ? 12 : 0; |
| time->tm_hour %= 24; |
| } else { |
| time->tm_hour = nvram_read(NVRAM_RTC_HOURS); |
| } |
| time->tm_year = nvram_read(NVRAM_RTC_YEAR); |
| } |
| |
| /* Instead of finding the century register, |
| we just make an assumption that if the year value is |
| less then 80, then it is 2000+ |
| */ |
| if (time->tm_year < 80) |
| time->tm_year += 100; |
| } |
| |
| /** |
| * Write the current time and date to the RTC |
| * |
| * @param time A pointer to a broken-down time structure |
| */ |
| void rtc_write_clock(const struct tm *time) |
| { |
| u16 timeout = 10000; |
| u8 statusB; |
| u8 reg8, year; |
| |
| while (nvram_updating()) |
| if (!timeout--) |
| return; |
| |
| statusB = nvram_read(NVRAM_RTC_STATUSB); |
| |
| year = time->tm_year; |
| if (year > 100) |
| year -= 100; |
| |
| if (!(statusB & NVRAM_RTC_FORMAT_BINARY)) { |
| nvram_write(dec2bcd(time->tm_mon + 1), NVRAM_RTC_MONTH); |
| nvram_write(dec2bcd(time->tm_sec), NVRAM_RTC_SECONDS); |
| nvram_write(dec2bcd(time->tm_min), NVRAM_RTC_MINUTES); |
| nvram_write(dec2bcd(time->tm_mday), NVRAM_RTC_DAY); |
| if (!(statusB & NVRAM_RTC_FORMAT_24HOUR)) { |
| if (time->tm_hour > 12) |
| reg8 = dec2bcd(time->tm_hour - 12) | 0x80; |
| else |
| reg8 = dec2bcd(time->tm_hour); |
| } else { |
| reg8 = dec2bcd(time->tm_hour); |
| } |
| nvram_write(reg8, NVRAM_RTC_HOURS); |
| nvram_write(dec2bcd(year), NVRAM_RTC_YEAR); |
| } else { |
| nvram_write(time->tm_mon + 1, NVRAM_RTC_MONTH); |
| nvram_write(time->tm_sec, NVRAM_RTC_SECONDS); |
| nvram_write(time->tm_min, NVRAM_RTC_MINUTES); |
| nvram_write(time->tm_mday, NVRAM_RTC_DAY); |
| if (!(statusB & NVRAM_RTC_FORMAT_24HOUR)) { |
| if (time->tm_hour > 12) |
| reg8 = (time->tm_hour - 12) | 0x80; |
| else |
| reg8 = time->tm_hour; |
| } else { |
| reg8 = time->tm_hour; |
| } |
| nvram_write(reg8, NVRAM_RTC_HOURS); |
| nvram_write(year, NVRAM_RTC_YEAR); |
| } |
| } |