390 lines
10 KiB
C
390 lines
10 KiB
C
/* readclock - read the real time clock Authors: T. Holm & E. Froese
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*
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* Changed to be user-space driver.
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*/
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/************************************************************************/
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/* */
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/* readclock.c */
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/* */
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/* Read the clock value from the 64 byte CMOS RAM */
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/* area, then set system time. */
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/* */
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/* If the machine ID byte is 0xFC or 0xF8, the device */
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/* /dev/mem exists and can be opened for reading, */
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/* and no errors in the CMOS RAM are reported by the */
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/* RTC, then the time is read from the clock RAM */
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/* area maintained by the RTC. */
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/* */
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/* The clock RAM values are decoded and fed to mktime */
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/* to make a time_t value, then stime(2) is called. */
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/* */
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/* This fails if: */
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/* */
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/* If the machine ID does not match 0xFC or 0xF8 (no */
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/* error message.) */
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/* */
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/* If the machine ID is 0xFC or 0xF8 and /dev/mem */
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/* is missing, or cannot be accessed. */
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/* */
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/* If the RTC reports errors in the CMOS RAM. */
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/* */
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/************************************************************************/
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/* origination 1987-Dec-29 efth */
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/* robustness 1990-Oct-06 C. Sylvain */
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/* incorp. B. Evans ideas 1991-Jul-06 C. Sylvain */
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/* set time & calibrate 1992-Dec-17 Kees J. Bot */
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/* clock timezone 1993-Oct-10 Kees J. Bot */
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/* set CMOS clock 1994-Jun-12 Kees J. Bot */
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/************************************************************************/
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#include <sys/types.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <time.h>
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#include <errno.h>
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#include <minix/type.h>
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#include <minix/const.h>
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#include <minix/syslib.h>
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#include <minix/sysutil.h>
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#include <minix/com.h>
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#include <machine/cmos.h>
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#include <sys/svrctl.h>
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int nflag = 0; /* Tell what, but don't do it. */
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int wflag = 0; /* Set the CMOS clock. */
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int Wflag = 0; /* Also set the CMOS clock register bits. */
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int y2kflag = 0; /* Interpret 1980 as 2000 for clock with Y2K bug. */
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#define MACH_ID_ADDR 0xFFFFE /* BIOS Machine ID at FFFF:000E */
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#define PC_AT 0xFC /* Machine ID byte for PC/AT,
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PC/XT286, and PS/2 Models 50, 60 */
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#define PS_386 0xF8 /* Machine ID byte for PS/2 Model 80 */
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/* Manufacturers usually use the ID value of the IBM model they emulate.
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* However some manufacturers, notably HP and COMPAQ, have had different
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* ideas in the past.
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*
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* Machine ID byte information source:
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* _The Programmer's PC Sourcebook_ by Thom Hogan,
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* published by Microsoft Press
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*/
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void errmsg(char *s);
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void get_time(struct tm *t);
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int read_register(int reg_addr);
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void set_time(struct tm *t);
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void write_register(int reg_addr, int value);
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int bcd_to_dec(int n);
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int dec_to_bcd(int n);
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void usage(void);
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/* SEF functions and variables. */
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FORWARD _PROTOTYPE( void sef_local_startup, (void) );
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int main(int argc, char **argv)
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{
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struct tm time1;
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struct tm time2;
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struct tm tmnow;
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char date[64];
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time_t now, rtc;
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int i, s;
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unsigned char mach_id, cmos_state;
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/* SEF local startup. */
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env_setargs(argc, argv);
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sef_local_startup();
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if((s=sys_readbios(MACH_ID_ADDR, &mach_id, sizeof(mach_id))) != OK) {
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printf("readclock: sys_readbios failed: %d.\n", s);
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exit(1);
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}
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if (mach_id != PS_386 && mach_id != PC_AT) {
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errmsg("Machine ID unknown." );
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printf("Machine ID byte = %02x\n", mach_id );
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exit(1);
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}
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cmos_state = read_register(CMOS_STATUS);
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if (cmos_state & (CS_LOST_POWER | CS_BAD_CHKSUM | CS_BAD_TIME)) {
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errmsg( "CMOS RAM error(s) found..." );
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printf("CMOS state = 0x%02x\n", cmos_state );
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if (cmos_state & CS_LOST_POWER)
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errmsg( "RTC lost power. Reset CMOS RAM with SETUP." );
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if (cmos_state & CS_BAD_CHKSUM)
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errmsg( "CMOS RAM checksum is bad. Run SETUP." );
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if (cmos_state & CS_BAD_TIME)
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errmsg( "Time invalid in CMOS RAM. Reset clock." );
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exit(1);
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}
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/* Process options. */
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while (argc > 1) {
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char *p = *++argv;
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if (*p++ != '-') usage();
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while (*p != 0) {
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switch (*p++) {
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case 'n': nflag = 1; break;
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case 'w': wflag = 1; break;
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case 'W': Wflag = 1; break;
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case '2': y2kflag = 1; break;
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default: usage();
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}
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}
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argc--;
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}
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if (Wflag) wflag = 1; /* -W implies -w */
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/* Read the CMOS real time clock. */
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for (i = 0; i < 10; i++) {
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get_time(&time1);
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now = time(NULL);
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time1.tm_isdst = -1; /* Do timezone calculations. */
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time2 = time1;
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rtc= mktime(&time1); /* Transform to a time_t. */
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if (rtc != -1) break;
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printf(
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"readclock: Invalid time read from CMOS RTC: %d-%02d-%02d %02d:%02d:%02d\n",
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time2.tm_year+1900, time2.tm_mon+1, time2.tm_mday,
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time2.tm_hour, time2.tm_min, time2.tm_sec);
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sleep(5);
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}
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if (i == 10) exit(1);
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if (!wflag) {
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/* Set system time. */
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if (nflag) {
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printf("stime(%lu)\n", (unsigned long) rtc);
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} else {
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if (stime(&rtc) < 0) {
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errmsg( "Not allowed to set time." );
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exit(1);
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}
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}
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tmnow = *localtime(&rtc);
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if (strftime(date, sizeof(date),
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"%a %b %d %H:%M:%S %Z %Y", &tmnow) != 0) {
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if (date[8] == '0') date[8]= ' ';
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printf("%s\n", date);
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}
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} else {
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/* Set the CMOS clock to the system time. */
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tmnow = *localtime(&now);
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if (nflag) {
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printf("%04d-%02d-%02d %02d:%02d:%02d\n",
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tmnow.tm_year + 1900,
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tmnow.tm_mon + 1,
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tmnow.tm_mday,
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tmnow.tm_hour,
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tmnow.tm_min,
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tmnow.tm_sec);
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} else {
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set_time(&tmnow);
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}
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}
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exit(0);
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}
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/*===========================================================================*
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* sef_local_startup *
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*===========================================================================*/
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PRIVATE void sef_local_startup()
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{
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/* Let SEF perform startup. */
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sef_startup();
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}
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void errmsg(char *s)
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{
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static char *prompt = "readclock: ";
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printf("%s%s\n", prompt, s);
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prompt = "";
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}
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/***********************************************************************/
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/* */
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/* get_time( time ) */
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/* */
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/* Update the structure pointed to by time with the current time */
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/* as read from CMOS RAM of the RTC. */
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/* If necessary, the time is converted into a binary format before */
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/* being stored in the structure. */
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/* */
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/***********************************************************************/
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void get_time(struct tm *t)
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{
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int osec, n;
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do {
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osec = -1;
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n = 0;
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do {
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/* Clock update in progress? */
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if (read_register(RTC_REG_A) & RTC_A_UIP) continue;
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t->tm_sec = read_register(RTC_SEC);
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if (t->tm_sec != osec) {
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/* Seconds changed. First from -1, then because the
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* clock ticked, which is what we're waiting for to
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* get a precise reading.
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*/
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osec = t->tm_sec;
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n++;
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}
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} while (n < 2);
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/* Read the other registers. */
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t->tm_min = read_register(RTC_MIN);
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t->tm_hour = read_register(RTC_HOUR);
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t->tm_mday = read_register(RTC_MDAY);
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t->tm_mon = read_register(RTC_MONTH);
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t->tm_year = read_register(RTC_YEAR);
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/* Time stable? */
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} while (read_register(RTC_SEC) != t->tm_sec
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|| read_register(RTC_MIN) != t->tm_min
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|| read_register(RTC_HOUR) != t->tm_hour
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|| read_register(RTC_MDAY) != t->tm_mday
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|| read_register(RTC_MONTH) != t->tm_mon
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|| read_register(RTC_YEAR) != t->tm_year);
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if ((read_register(RTC_REG_B) & RTC_B_DM_BCD) == 0) {
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/* Convert BCD to binary (default RTC mode). */
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t->tm_year = bcd_to_dec(t->tm_year);
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t->tm_mon = bcd_to_dec(t->tm_mon);
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t->tm_mday = bcd_to_dec(t->tm_mday);
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t->tm_hour = bcd_to_dec(t->tm_hour);
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t->tm_min = bcd_to_dec(t->tm_min);
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t->tm_sec = bcd_to_dec(t->tm_sec);
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}
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t->tm_mon--; /* Counts from 0. */
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/* Correct the year, good until 2080. */
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if (t->tm_year < 80) t->tm_year += 100;
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if (y2kflag) {
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/* Clock with Y2K bug, interpret 1980 as 2000, good until 2020. */
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if (t->tm_year < 100) t->tm_year += 20;
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}
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}
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int read_register(int reg_addr)
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{
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u32_t r;
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if(sys_outb(RTC_INDEX, reg_addr) != OK) {
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printf("cmos: outb failed of %x\n", RTC_INDEX);
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exit(1);
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}
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if(sys_inb(RTC_IO, &r) != OK) {
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printf("cmos: inb failed of %x (index %x) failed\n", RTC_IO, reg_addr);
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exit(1);
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}
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return r;
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}
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/***********************************************************************/
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/* */
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/* set_time( time ) */
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/* */
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/* Set the CMOS RTC to the time found in the structure. */
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/* */
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/***********************************************************************/
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void set_time(struct tm *t)
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{
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int regA, regB;
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if (Wflag) {
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/* Set A and B registers to their proper values according to the AT
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* reference manual. (For if it gets messed up, but the BIOS doesn't
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* repair it.)
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*/
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write_register(RTC_REG_A, RTC_A_DV_OK | RTC_A_RS_DEF);
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write_register(RTC_REG_B, RTC_B_24);
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}
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/* Inhibit updates. */
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regB= read_register(RTC_REG_B);
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write_register(RTC_REG_B, regB | RTC_B_SET);
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t->tm_mon++; /* Counts from 1. */
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if (y2kflag) {
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/* Set the clock back 20 years to avoid Y2K bug, good until 2020. */
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if (t->tm_year >= 100) t->tm_year -= 20;
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}
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if ((regB & 0x04) == 0) {
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/* Convert binary to BCD (default RTC mode) */
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t->tm_year = dec_to_bcd(t->tm_year % 100);
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t->tm_mon = dec_to_bcd(t->tm_mon);
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t->tm_mday = dec_to_bcd(t->tm_mday);
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t->tm_hour = dec_to_bcd(t->tm_hour);
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t->tm_min = dec_to_bcd(t->tm_min);
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t->tm_sec = dec_to_bcd(t->tm_sec);
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}
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write_register(RTC_YEAR, t->tm_year);
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write_register(RTC_MONTH, t->tm_mon);
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write_register(RTC_MDAY, t->tm_mday);
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write_register(RTC_HOUR, t->tm_hour);
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write_register(RTC_MIN, t->tm_min);
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write_register(RTC_SEC, t->tm_sec);
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/* Stop the clock. */
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regA= read_register(RTC_REG_A);
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write_register(RTC_REG_A, regA | RTC_A_DV_STOP);
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/* Allow updates and restart the clock. */
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write_register(RTC_REG_B, regB);
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write_register(RTC_REG_A, regA);
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}
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void write_register(int reg_addr, int value)
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{
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if(sys_outb(RTC_INDEX, reg_addr) != OK) {
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printf("cmos: outb failed of %x\n", RTC_INDEX);
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exit(1);
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}
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if(sys_outb(RTC_IO, value) != OK) {
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printf("cmos: outb failed of %x (index %x)\n", RTC_IO, reg_addr);
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exit(1);
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}
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}
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int bcd_to_dec(int n)
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{
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return ((n >> 4) & 0x0F) * 10 + (n & 0x0F);
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}
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int dec_to_bcd(int n)
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{
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return ((n / 10) << 4) | (n % 10);
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}
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void usage(void)
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{
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printf("Usage: readclock [-nwW2]\n");
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exit(1);
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}
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