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[time] Add RTC-based time source

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Add a time source using the CMOS RTC to obtain the current time.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2012-03-19 17:08:51 +00:00
parent 846bde90e6
commit 12002d6955
6 changed files with 242 additions and 40 deletions
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40
src/arch/i386/interface/pcbios/rtc_entropy.c
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@@ -22,53 +22,15 @@ FILE_LICENCE ( GPL2_OR_LATER );
*
* RTC-based entropy source
*
* The CMOS/RTC registers are documented (with varying degrees of
* accuracy and consistency) at
*
* http://www.nondot.org/sabre/os/files/MiscHW/RealtimeClockFAQ.txt
* http://wiki.osdev.org/RTC
* http://wiki.osdev.org/CMOS
*/
#include <stdint.h>
#include <string.h>
#include <biosint.h>
#include <pic8259.h>
#include <rtc.h>
#include <ipxe/entropy.h>
/** RTC IRQ */
#define RTC_IRQ 8
/** RTC interrupt vector */
#define RTC_INT IRQ_INT ( RTC_IRQ )
/** CMOS/RTC address (and NMI) register */
#define CMOS_ADDRESS 0x70
/** NMI disable bit */
#define CMOS_DISABLE_NMI 0x80
/** CMOS/RTC data register */
#define CMOS_DATA 0x71
/** RTC status register A */
#define RTC_STATUS_A 0x0a
/** RTC status register B */
#define RTC_STATUS_B 0x0b
/** RTC Periodic Interrupt Enabled bit */
#define RTC_STATUS_B_PIE 0x40
/** RTC status register C */
#define RTC_STATUS_C 0x0c
/** RTC status register D */
#define RTC_STATUS_D 0x0d
/** CMOS default address */
#define CMOS_DEFAULT_ADDRESS RTC_STATUS_D
/** RTC "interrupt triggered" flag */
static uint8_t __text16 ( rtc_flag );
#define rtc_flag __use_text16 ( rtc_flag )