| /* |
| * This file is part of the libpayload project. |
| * |
| * Copyright (C) 2008 Uwe Hermann <uwe@hermann-uwe.de> |
| * |
| * 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.h> |
| |
| #define RTC_PORT 0x70 |
| |
| /** |
| * 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) |
| { |
| 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) |
| { |
| outb(addr, RTC_PORT); |
| outb(val, RTC_PORT + 1); |
| } |