diff options
Diffstat (limited to 'arch/mips/sibyte/swarm/time.c')
| -rw-r--r-- | arch/mips/sibyte/swarm/time.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/arch/mips/sibyte/swarm/time.c b/arch/mips/sibyte/swarm/time.c new file mode 100644 index 00000000000..c1f1a9defee --- /dev/null +++ b/arch/mips/sibyte/swarm/time.c @@ -0,0 +1,244 @@ +/* + * 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); + } +} |