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/*
* Copyright (C) 2000, 2001 Broadcom Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/*
* Time routines for the swarm board. We pass all the hard stuff
* through to the sb1250 handling code. Only thing we really keep
* track of here is what time of day we think it is. And we don't
* really even do a good job of that...
*/
#include <linux/bcd.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <asm/system.h>
#include <asm/addrspace.h>
#include <asm/io.h>
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_smbus.h>
static unsigned long long sec_bias = 0;
static unsigned int usec_bias = 0;
/* Xicor 1241 definitions */
/*
* Register bits
*/
#define X1241REG_SR_BAT 0x80 /* currently on battery power */
#define X1241REG_SR_RWEL 0x04 /* r/w latch is enabled, can write RTC */
#define X1241REG_SR_WEL 0x02 /* r/w latch is unlocked, can enable r/w now */
#define X1241REG_SR_RTCF 0x01 /* clock failed */
#define X1241REG_BL_BP2 0x80 /* block protect 2 */
#define X1241REG_BL_BP1 0x40 /* block protect 1 */
#define X1241REG_BL_BP0 0x20 /* block protect 0 */
#define X1241REG_BL_WD1 0x10
#define X1241REG_BL_WD0 0x08
#define X1241REG_HR_MIL 0x80 /* military time format */
/*
* Register numbers
*/
#define X1241REG_BL 0x10 /* block protect bits */
#define X1241REG_INT 0x11 /* */
#define X1241REG_SC 0x30 /* Seconds */
#define X1241REG_MN 0x31 /* Minutes */
#define X1241REG_HR 0x32 /* Hours */
#define X1241REG_DT 0x33 /* Day of month */
#define X1241REG_MO 0x34 /* Month */
#define X1241REG_YR 0x35 /* Year */
#define X1241REG_DW 0x36 /* Day of Week */
#define X1241REG_Y2K 0x37 /* Year 2K */
#define X1241REG_SR 0x3F /* Status register */
#define X1241_CCR_ADDRESS 0x6F
#define SMB_CSR(reg) (IOADDR(A_SMB_REGISTER(1, reg)))
static int xicor_read(uint8_t addr)
{
while (bus_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
bus_writeq((addr >> 8) & 0x7, SMB_CSR(R_SMB_CMD));
bus_writeq((addr & 0xff), SMB_CSR(R_SMB_DATA));
bus_writeq((V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR2BYTE),
SMB_CSR(R_SMB_START));
while (bus_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
bus_writeq((V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_RD1BYTE),
SMB_CSR(R_SMB_START));
while (bus_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
if (bus_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
/* Clear error bit by writing a 1 */
bus_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
return -1;
}
return (bus_readq(SMB_CSR(R_SMB_DATA)) & 0xff);
}
static int xicor_write(uint8_t addr, int b)
{
while (bus_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
bus_writeq(addr, SMB_CSR(R_SMB_CMD));
bus_writeq((addr & 0xff) | ((b & 0xff) << 8), SMB_CSR(R_SMB_DATA));
bus_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR3BYTE,
SMB_CSR(R_SMB_START));
while (bus_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
if (bus_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
/* Clear error bit by writing a 1 */
bus_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
return -1;
} else {
return 0;
}
}
/*
* In order to set the CMOS clock precisely, set_rtc_mmss has to be
* called 500 ms after the second nowtime has started, because when
* nowtime is written into the registers of the CMOS clock, it will
* jump to the next second precisely 500 ms later. Check the Motorola
* MC146818A or Dallas DS12887 data sheet for details.
*
* BUG: This routine does not handle hour overflow properly; it just
* sets the minutes. Usually you'll only notice that after reboot!
*/
int set_rtc_mmss(unsigned long nowtime)
{
int retval = 0;
int real_seconds, real_minutes, cmos_minutes;
cmos_minutes = xicor_read(X1241REG_MN);
cmos_minutes = BCD2BIN(cmos_minutes);
/*
* since we're only adjusting minutes and seconds,
* don't interfere with hour overflow. This avoids
* messing with unknown time zones but requires your
* RTC not to be off by more than 15 minutes
*/
real_seconds = nowtime % 60;
real_minutes = nowtime / 60;
if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
real_minutes += 30; /* correct for half hour time zone */
real_minutes %= 60;
/* unlock writes to the CCR */
xicor_write(X1241REG_SR, X1241REG_SR_WEL);
xicor_write(X1241REG_SR, X1241REG_SR_WEL | X1241REG_SR_RWEL);
if (abs(real_minutes - cmos_minutes) < 30) {
real_seconds = BIN2BCD(real_seconds);
real_minutes = BIN2BCD(real_minutes);
xicor_write(X1241REG_SC, real_seconds);
xicor_write(X1241REG_MN, real_minutes);
} else {
printk(KERN_WARNING
"set_rtc_mmss: can't update from %d to %d\n",
cmos_minutes, real_minutes);
retval = -1;
}
xicor_write(X1241REG_SR, 0);
printk("set_rtc_mmss: %02d:%02d\n", real_minutes, real_seconds);
return retval;
}
static unsigned long __init get_swarm_time(void)
{
unsigned int year, mon, day, hour, min, sec, y2k;
sec = xicor_read(X1241REG_SC);
min = xicor_read(X1241REG_MN);
hour = xicor_read(X1241REG_HR);
if (hour & X1241REG_HR_MIL) {
hour &= 0x3f;
} else {
if (hour & 0x20)
hour = (hour & 0xf) + 0x12;
}
sec = BCD2BIN(sec);
min = BCD2BIN(min);
hour = BCD2BIN(hour);
day = xicor_read(X1241REG_DT);
mon = xicor_read(X1241REG_MO);
year = xicor_read(X1241REG_YR);
y2k = xicor_read(X1241REG_Y2K);
day = BCD2BIN(day);
mon = BCD2BIN(mon);
year = BCD2BIN(year);
y2k = BCD2BIN(y2k);
year += (y2k * 100);
return mktime(year, mon, day, hour, min, sec);
}
/*
* Bring up the timer at 100 Hz.
*/
void __init swarm_time_init(void)
{
unsigned int flags;
int status;
/* Set up the scd general purpose timer 0 to cpu 0 */
sb1250_time_init();
/* Establish communication with the Xicor 1241 RTC */
/* XXXKW how do I share the SMBus with the I2C subsystem? */
bus_writeq(K_SMB_FREQ_400KHZ, SMB_CSR(R_SMB_FREQ));
bus_writeq(0, SMB_CSR(R_SMB_CONTROL));
if ((status = xicor_read(X1241REG_SR_RTCF)) < 0) {
printk("x1241: couldn't detect on SWARM SMBus 1\n");
} else {
if (status & X1241REG_SR_RTCF)
printk("x1241: battery failed -- time is probably wrong\n");
write_seqlock_irqsave(&xtime_lock, flags);
xtime.tv_sec = get_swarm_time();
xtime.tv_nsec = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
}
}
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