linux/arch/mips/sibyte/swarm/rtc_xicor1241.c
Atsushi Nemoto 53c2df2f4e Use rtc_lock to protect RTC operations
Many RTC routines were not protected against each other, so there are
potential races, for example, ntp-update against /dev/rtc.  This patch
fixes them using rtc_lock.
    
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2005-11-07 18:05:38 +00:00

209 lines
5.3 KiB
C

/*
* Copyright (C) 2000, 2001 Broadcom Corporation
*
* Copyright (C) 2002 MontaVista Software Inc.
* Author: jsun@mvista.com or jsun@junsun.net
*
* 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.
*/
#include <linux/bcd.h>
#include <linux/types.h>
#include <linux/time.h>
#include <asm/time.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>
/* 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 (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
__raw_writeq((addr >> 8) & 0x7, SMB_CSR(R_SMB_CMD));
__raw_writeq(addr & 0xff, SMB_CSR(R_SMB_DATA));
__raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR2BYTE,
SMB_CSR(R_SMB_START));
while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
__raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_RD1BYTE,
SMB_CSR(R_SMB_START));
while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
/* Clear error bit by writing a 1 */
__raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
return -1;
}
return (__raw_readq(SMB_CSR(R_SMB_DATA)) & 0xff);
}
static int xicor_write(uint8_t addr, int b)
{
while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
__raw_writeq(addr, SMB_CSR(R_SMB_CMD));
__raw_writeq((addr & 0xff) | ((b & 0xff) << 8), SMB_CSR(R_SMB_DATA));
__raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR3BYTE,
SMB_CSR(R_SMB_START));
while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
/* Clear error bit by writing a 1 */
__raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
return -1;
} else {
return 0;
}
}
int xicor_set_time(unsigned long t)
{
struct rtc_time tm;
int tmp;
unsigned long flags;
to_tm(t, &tm);
spin_lock_irqsave(&rtc_lock, flags);
/* unlock writes to the CCR */
xicor_write(X1241REG_SR, X1241REG_SR_WEL);
xicor_write(X1241REG_SR, X1241REG_SR_WEL | X1241REG_SR_RWEL);
/* trivial ones */
tm.tm_sec = BIN2BCD(tm.tm_sec);
xicor_write(X1241REG_SC, tm.tm_sec);
tm.tm_min = BIN2BCD(tm.tm_min);
xicor_write(X1241REG_MN, tm.tm_min);
tm.tm_mday = BIN2BCD(tm.tm_mday);
xicor_write(X1241REG_DT, tm.tm_mday);
/* tm_mon starts from 0, *ick* */
tm.tm_mon ++;
tm.tm_mon = BIN2BCD(tm.tm_mon);
xicor_write(X1241REG_MO, tm.tm_mon);
/* year is split */
tmp = tm.tm_year / 100;
tm.tm_year %= 100;
xicor_write(X1241REG_YR, tm.tm_year);
xicor_write(X1241REG_Y2K, tmp);
/* hour is the most tricky one */
tmp = xicor_read(X1241REG_HR);
if (tmp & X1241REG_HR_MIL) {
/* 24 hour format */
tm.tm_hour = BIN2BCD(tm.tm_hour);
tmp = (tmp & ~0x3f) | (tm.tm_hour & 0x3f);
} else {
/* 12 hour format, with 0x2 for pm */
tmp = tmp & ~0x3f;
if (tm.tm_hour >= 12) {
tmp |= 0x20;
tm.tm_hour -= 12;
}
tm.tm_hour = BIN2BCD(tm.tm_hour);
tmp |= tm.tm_hour;
}
xicor_write(X1241REG_HR, tmp);
xicor_write(X1241REG_SR, 0);
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
unsigned long xicor_get_time(void)
{
unsigned int year, mon, day, hour, min, sec, y2k;
unsigned long flags;
spin_lock_irqsave(&rtc_lock, flags);
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;
}
day = xicor_read(X1241REG_DT);
mon = xicor_read(X1241REG_MO);
year = xicor_read(X1241REG_YR);
y2k = xicor_read(X1241REG_Y2K);
spin_unlock_irqrestore(&rtc_lock, flags);
sec = BCD2BIN(sec);
min = BCD2BIN(min);
hour = BCD2BIN(hour);
day = BCD2BIN(day);
mon = BCD2BIN(mon);
year = BCD2BIN(year);
y2k = BCD2BIN(y2k);
year += (y2k * 100);
return mktime(year, mon, day, hour, min, sec);
}
int xicor_probe(void)
{
return (xicor_read(X1241REG_SC) != -1);
}