diff options
Diffstat (limited to 'payloads/libpayload/drivers')
-rw-r--r-- | payloads/libpayload/drivers/Makefile.inc | 1 | ||||
-rw-r--r-- | payloads/libpayload/drivers/cmos.c | 69 |
2 files changed, 70 insertions, 0 deletions
diff --git a/payloads/libpayload/drivers/Makefile.inc b/payloads/libpayload/drivers/Makefile.inc index 8a39e4a4dd..08e7150037 100644 --- a/payloads/libpayload/drivers/Makefile.inc +++ b/payloads/libpayload/drivers/Makefile.inc @@ -31,3 +31,4 @@ TARGETS-$(CONFIG_SERIAL_CONSOLE) += drivers/serial.o TARGETS-$(CONFIG_VGA_CONSOLE) += drivers/vga.o TARGETS-$(CONFIG_PC_KEYBOARD) += drivers/keyboard.o +TARGETS-$(CONFIG_CMOS) += drivers/cmos.o diff --git a/payloads/libpayload/drivers/cmos.c b/payloads/libpayload/drivers/cmos.c new file mode 100644 index 0000000000..c8cd605a0a --- /dev/null +++ b/payloads/libpayload/drivers/cmos.c @@ -0,0 +1,69 @@ +/* + * 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 CMOS address. + * + * @param addr The CMOS address to read a byte from. + * @return The byte at the given CMOS address. + */ +u8 cmos_read(u8 addr) +{ + outb(addr, RTC_PORT); + return inb(RTC_PORT + 1); +} + +/** + * Write a byte to the specified CMOS address. + * + * @param val The byte to write to CMOS. + * @param addr The CMOS address to write to. + */ +void cmos_write(u8 val, u8 addr) +{ + outb(addr, RTC_PORT); + outb(val, RTC_PORT + 1); +} |