265 lines
7.7 KiB
C
265 lines
7.7 KiB
C
/* This file contains a device driver that can access the CMOS chip to
|
|
* get or set the system time. It drives the special file:
|
|
*
|
|
* /dev/cmos - CMOS chip
|
|
*
|
|
* Changes:
|
|
* Aug 04, 2005 Created. Read CMOS time. (Jorrit N. Herder)
|
|
*
|
|
* Manufacturers usually use the ID value of the IBM model they emulate.
|
|
* However some manufacturers, notably HP and COMPAQ, have had different
|
|
* ideas in the past.
|
|
*
|
|
* Machine ID byte information source:
|
|
* _The Programmer's PC Sourcebook_ by Thom Hogan,
|
|
* published by Microsoft Press
|
|
*/
|
|
|
|
#include "../drivers.h"
|
|
#include <sys/ioc_cmos.h>
|
|
#include <time.h>
|
|
#include <ibm/cmos.h>
|
|
#include <ibm/bios.h>
|
|
|
|
extern int errno; /* error number for PM calls */
|
|
|
|
FORWARD _PROTOTYPE( int gettime, (int who, int y2kflag, vir_bytes dst_time));
|
|
FORWARD _PROTOTYPE( void reply, (int reply, int replyee, int proc, int s));
|
|
|
|
FORWARD _PROTOTYPE( int read_register, (int register_address));
|
|
FORWARD _PROTOTYPE( int get_cmostime, (struct tm *tmp, int y2kflag));
|
|
FORWARD _PROTOTYPE( int dec_to_bcd, (int dec));
|
|
FORWARD _PROTOTYPE( int bcd_to_dec, (int bcd));
|
|
|
|
/*===========================================================================*
|
|
* main *
|
|
*===========================================================================*/
|
|
PUBLIC void main(void)
|
|
{
|
|
message m;
|
|
int y2kflag;
|
|
int result;
|
|
int suspended = NONE;
|
|
int s;
|
|
|
|
while(TRUE) {
|
|
|
|
/* Get work. */
|
|
if (OK != (s=receive(ANY, &m)))
|
|
panic("CMOS", "attempt to receive work failed", s);
|
|
|
|
/* Handle request. */
|
|
switch(m.m_type) {
|
|
|
|
case DEV_OPEN:
|
|
case DEV_CLOSE:
|
|
case CANCEL:
|
|
reply(TASK_REPLY, m.m_source, m.PROC_NR, OK);
|
|
break;
|
|
|
|
case DEV_PING:
|
|
notify(m.m_source);
|
|
break;
|
|
case DEV_IOCTL:
|
|
|
|
/* Probably best to SUSPEND the caller, CMOS I/O has nasty timeouts.
|
|
* This way we don't block the rest of the system. First check if
|
|
* another process is already suspended. We cannot handle multiple
|
|
* requests at a time.
|
|
*/
|
|
if (suspended != NONE) {
|
|
reply(TASK_REPLY, m.m_source, m.PROC_NR, EBUSY);
|
|
break;
|
|
}
|
|
suspended = m.PROC_NR;
|
|
reply(TASK_REPLY, m.m_source, m.PROC_NR, SUSPEND);
|
|
|
|
switch(m.REQUEST) {
|
|
case CIOCGETTIME: /* get CMOS time */
|
|
case CIOCGETTIMEY2K:
|
|
y2kflag = (m.REQUEST = CIOCGETTIME) ? 0 : 1;
|
|
result = gettime(m.PROC_NR, y2kflag, (vir_bytes) m.ADDRESS);
|
|
break;
|
|
case CIOCSETTIME:
|
|
case CIOCSETTIMEY2K:
|
|
default: /* unsupported ioctl */
|
|
result = ENOSYS;
|
|
}
|
|
|
|
/* Request completed. Tell the caller to check our status. */
|
|
notify(m.m_source);
|
|
break;
|
|
|
|
case DEV_STATUS:
|
|
|
|
/* The FS calls back to get our status. Revive the suspended
|
|
* processes and return the status of reading the CMOS.
|
|
*/
|
|
if (suspended == NONE)
|
|
reply(DEV_NO_STATUS, m.m_source, NONE, OK);
|
|
else
|
|
reply(DEV_REVIVE, m.m_source, suspended, result);
|
|
suspended = NONE;
|
|
break;
|
|
|
|
case SYN_ALARM: /* shouldn't happen */
|
|
case SYS_SIG: /* ignore system events */
|
|
continue;
|
|
|
|
default:
|
|
reply(TASK_REPLY, m.m_source, m.PROC_NR, EINVAL);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* reply *
|
|
*===========================================================================*/
|
|
PRIVATE void reply(int code, int replyee, int process, int status)
|
|
{
|
|
message m;
|
|
int s;
|
|
|
|
m.m_type = code; /* TASK_REPLY or REVIVE */
|
|
m.REP_STATUS = status; /* result of device operation */
|
|
m.REP_PROC_NR = process; /* which user made the request */
|
|
if (OK != (s=send(replyee, &m)))
|
|
panic("CMOS", "sending reply failed", s);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* gettime *
|
|
*===========================================================================*/
|
|
PRIVATE int gettime(int who, int y2kflag, vir_bytes dst_time)
|
|
{
|
|
unsigned char mach_id, cmos_state;
|
|
struct tm time1;
|
|
int i, s;
|
|
|
|
/* First obtain the machine ID to see if we can read the CMOS clock. Only
|
|
* for PS_386 and PC_AT this is possible. Otherwise, return an error.
|
|
*/
|
|
sys_vircopy(SELF, BIOS_SEG, (vir_bytes) MACHINE_ID_ADDR,
|
|
SELF, D, (vir_bytes) &mach_id, MACHINE_ID_SIZE);
|
|
if (mach_id != PS_386_MACHINE && mach_id != PC_AT_MACHINE) {
|
|
printf("IS: Machine ID unknown. ID byte = %02x.\n", mach_id);
|
|
return(EFAULT);
|
|
}
|
|
|
|
/* Now check the CMOS' state to see if we can read a proper time from it.
|
|
* If the state is crappy, return an error.
|
|
*/
|
|
cmos_state = read_register(CMOS_STATUS);
|
|
if (cmos_state & (CS_LOST_POWER | CS_BAD_CHKSUM | CS_BAD_TIME)) {
|
|
printf( "IS: CMOS RAM error(s) found. State = 0x%02x\n", cmos_state );
|
|
if (cmos_state & CS_LOST_POWER)
|
|
printf("IS: RTC lost power. Reset CMOS RAM with SETUP." );
|
|
if (cmos_state & CS_BAD_CHKSUM)
|
|
printf("IS: CMOS RAM checksum is bad. Run SETUP." );
|
|
if (cmos_state & CS_BAD_TIME)
|
|
printf("IS: Time invalid in CMOS RAM. Reset clock." );
|
|
return(EFAULT);
|
|
}
|
|
|
|
/* Everything seems to be OK. Read the CMOS real time clock and copy the
|
|
* result back to the caller.
|
|
*/
|
|
if (get_cmostime(&time1, y2kflag) != 0)
|
|
return(EFAULT);
|
|
sys_datacopy(SELF, (vir_bytes) &time1,
|
|
who, dst_time, sizeof(struct tm));
|
|
|
|
return(OK);
|
|
}
|
|
|
|
PRIVATE int get_cmostime(struct tm *t, int y2kflag)
|
|
{
|
|
/* Update the structure pointed to by time with the current time as read
|
|
* from CMOS RAM of the RTC. If necessary, the time is converted into a
|
|
* binary format before being stored in the structure.
|
|
*/
|
|
int osec, n;
|
|
unsigned long i;
|
|
clock_t t0,t1;
|
|
|
|
/* Start a timer to keep us from getting stuck on a dead clock. */
|
|
getuptime(&t0);
|
|
do {
|
|
osec = -1;
|
|
n = 0;
|
|
do {
|
|
getuptime(&t1);
|
|
if (t1-t0 > 5*HZ) {
|
|
printf("readclock: CMOS clock appears dead\n");
|
|
return(1);
|
|
}
|
|
|
|
/* Clock update in progress? */
|
|
if (read_register(RTC_REG_A) & RTC_A_UIP) continue;
|
|
|
|
t->tm_sec = read_register(RTC_SEC);
|
|
if (t->tm_sec != osec) {
|
|
/* Seconds changed. First from -1, then because the
|
|
* clock ticked, which is what we're waiting for to
|
|
* get a precise reading.
|
|
*/
|
|
osec = t->tm_sec;
|
|
n++;
|
|
}
|
|
} while (n < 2);
|
|
|
|
/* Read the other registers. */
|
|
t->tm_min = read_register(RTC_MIN);
|
|
t->tm_hour = read_register(RTC_HOUR);
|
|
t->tm_mday = read_register(RTC_MDAY);
|
|
t->tm_mon = read_register(RTC_MONTH);
|
|
t->tm_year = read_register(RTC_YEAR);
|
|
|
|
/* Time stable? */
|
|
} while (read_register(RTC_SEC) != t->tm_sec
|
|
|| read_register(RTC_MIN) != t->tm_min
|
|
|| read_register(RTC_HOUR) != t->tm_hour
|
|
|| read_register(RTC_MDAY) != t->tm_mday
|
|
|| read_register(RTC_MONTH) != t->tm_mon
|
|
|| read_register(RTC_YEAR) != t->tm_year);
|
|
|
|
if ((read_register(RTC_REG_B) & RTC_B_DM_BCD) == 0) {
|
|
/* Convert BCD to binary (default RTC mode). */
|
|
t->tm_year = bcd_to_dec(t->tm_year);
|
|
t->tm_mon = bcd_to_dec(t->tm_mon);
|
|
t->tm_mday = bcd_to_dec(t->tm_mday);
|
|
t->tm_hour = bcd_to_dec(t->tm_hour);
|
|
t->tm_min = bcd_to_dec(t->tm_min);
|
|
t->tm_sec = bcd_to_dec(t->tm_sec);
|
|
}
|
|
t->tm_mon--; /* Counts from 0. */
|
|
|
|
/* Correct the year, good until 2080. */
|
|
if (t->tm_year < 80) t->tm_year += 100;
|
|
|
|
if (y2kflag) {
|
|
/* Clock with Y2K bug, interpret 1980 as 2000, good until 2020. */
|
|
if (t->tm_year < 100) t->tm_year += 20;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
PRIVATE int read_register(int reg_addr)
|
|
{
|
|
/* Read a single CMOS register value. */
|
|
int r = 0;
|
|
sys_outb(RTC_INDEX, reg_addr);
|
|
sys_inb(RTC_IO, &r);
|
|
return r;
|
|
}
|
|
|
|
PRIVATE int bcd_to_dec(int n)
|
|
{
|
|
return ((n >> 4) & 0x0F) * 10 + (n & 0x0F);
|
|
}
|
|
|
|
PRIVATE int dec_to_bcd(int n)
|
|
{
|
|
return ((n / 10) << 4) | (n % 10);
|
|
}
|
|
|