[linux.git] / arch / m68k / bvme6000 / config.c

/*
 *  arch/m68k/bvme6000/config.c
 *
 *  Copyright (C) 1997 Richard Hirst [[email protected]]
 *
 * Based on:
 *
 *  linux/amiga/config.c
 *
 *  Copyright (C) 1993 Hamish Macdonald
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file README.legal in the main directory of this archive
 * for more details.
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/tty.h>
#include <linux/console.h>
#include <linux/linkage.h>
#include <linux/init.h>
#include <linux/major.h>
#include <linux/genhd.h>
#include <linux/rtc.h>
#include <linux/interrupt.h>
#include <linux/bcd.h>

#include <asm/bootinfo.h>
#include <asm/pgtable.h>
#include <asm/setup.h>
#include <asm/irq.h>
#include <asm/traps.h>
#include <asm/rtc.h>
#include <asm/machdep.h>
#include <asm/bvme6000hw.h>

static void bvme6000_get_model(char *model);
extern void bvme6000_sched_init(irq_handler_t handler);
extern u32 bvme6000_gettimeoffset(void);
extern int bvme6000_hwclk (int, struct rtc_time *);
extern int bvme6000_set_clock_mmss (unsigned long);
extern void bvme6000_reset (void);
void bvme6000_set_vectors (void);

/* Save tick handler routine pointer, will point to xtime_update() in
 * kernel/timer/timekeeping.c, called via bvme6000_process_int() */

static irq_handler_t tick_handler;


int bvme6000_parse_bootinfo(const struct bi_record *bi)
{
	if (bi->tag == BI_VME_TYPE)
		return 0;
	else
		return 1;
}

void bvme6000_reset(void)
{
	volatile PitRegsPtr pit = (PitRegsPtr)BVME_PIT_BASE;

	printk ("\r\n\nCalled bvme6000_reset\r\n"
			"\r\r\r\r\r\r\r\r\r\r\r\r\r\r\r\r\r\r");
	/* The string of returns is to delay the reset until the whole
	 * message is output. */
	/* Enable the watchdog, via PIT port C bit 4 */

	pit->pcddr	|= 0x10;	/* WDOG enable */

	while(1)
		;
}

static void bvme6000_get_model(char *model)
{
    sprintf(model, "BVME%d000", m68k_cputype == CPU_68060 ? 6 : 4);
}

/*
 * This function is called during kernel startup to initialize
 * the bvme6000 IRQ handling routines.
 */
static void __init bvme6000_init_IRQ(void)
{
	m68k_setup_user_interrupt(VEC_USER, 192);
}

void __init config_bvme6000(void)
{
    volatile PitRegsPtr pit = (PitRegsPtr)BVME_PIT_BASE;

    /* Board type is only set by newer versions of vmelilo/tftplilo */
    if (!vme_brdtype) {
	if (m68k_cputype == CPU_68060)
	    vme_brdtype = VME_TYPE_BVME6000;
	else
	    vme_brdtype = VME_TYPE_BVME4000;
    }
#if 0
    /* Call bvme6000_set_vectors() so ABORT will work, along with BVMBug
     * debugger.  Note trap_init() will splat the abort vector, but
     * bvme6000_init_IRQ() will put it back again.  Hopefully. */

    bvme6000_set_vectors();
#endif

    mach_max_dma_address = 0xffffffff;
    mach_sched_init      = bvme6000_sched_init;
    mach_init_IRQ        = bvme6000_init_IRQ;
    arch_gettimeoffset   = bvme6000_gettimeoffset;
    mach_hwclk           = bvme6000_hwclk;
    mach_set_clock_mmss	 = bvme6000_set_clock_mmss;
    mach_reset		 = bvme6000_reset;
    mach_get_model       = bvme6000_get_model;

    printk ("Board is %sconfigured as a System Controller\n",
		*config_reg_ptr & BVME_CONFIG_SW1 ? "" : "not ");

    /* Now do the PIT configuration */

    pit->pgcr	= 0x00;	/* Unidirectional 8 bit, no handshake for now */
    pit->psrr	= 0x18;	/* PIACK and PIRQ functions enabled */
    pit->pacr	= 0x00;	/* Sub Mode 00, H2 i/p, no DMA */
    pit->padr	= 0x00;	/* Just to be tidy! */
    pit->paddr	= 0x00;	/* All inputs for now (safest) */
    pit->pbcr	= 0x80;	/* Sub Mode 1x, H4 i/p, no DMA */
    pit->pbdr	= 0xbc | (*config_reg_ptr & BVME_CONFIG_SW1 ? 0 : 0x40);
			/* PRI, SYSCON?, Level3, SCC clks from xtal */
    pit->pbddr	= 0xf3;	/* Mostly outputs */
    pit->pcdr	= 0x01;	/* PA transceiver disabled */
    pit->pcddr	= 0x03;	/* WDOG disable */

    /* Disable snooping for Ethernet and VME accesses */

    bvme_acr_addrctl = 0;
}


irqreturn_t bvme6000_abort_int (int irq, void *dev_id)
{
        unsigned long *new = (unsigned long *)vectors;
        unsigned long *old = (unsigned long *)0xf8000000;

        /* Wait for button release */
        while (*(volatile unsigned char *)BVME_LOCAL_IRQ_STAT & BVME_ABORT_STATUS)
                ;

        *(new+4) = *(old+4);            /* Illegal instruction */
        *(new+9) = *(old+9);            /* Trace */
        *(new+47) = *(old+47);          /* Trap #15 */
        *(new+0x1f) = *(old+0x1f);      /* ABORT switch */
	return IRQ_HANDLED;
}


static irqreturn_t bvme6000_timer_int (int irq, void *dev_id)
{
    volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
    unsigned char msr = rtc->msr & 0xc0;

    rtc->msr = msr | 0x20;		/* Ack the interrupt */

    return tick_handler(irq, dev_id);
}

/*
 * Set up the RTC timer 1 to mode 2, so T1 output toggles every 5ms
 * (40000 x 125ns).  It will interrupt every 10ms, when T1 goes low.
 * So, when reading the elapsed time, you should read timer1,
 * subtract it from 39999, and then add 40000 if T1 is high.
 * That gives you the number of 125ns ticks in to the 10ms period,
 * so divide by 8 to get the microsecond result.
 */

void bvme6000_sched_init (irq_handler_t timer_routine)
{
    volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
    unsigned char msr = rtc->msr & 0xc0;

    rtc->msr = 0;	/* Ensure timer registers accessible */

    tick_handler = timer_routine;
    if (request_irq(BVME_IRQ_RTC, bvme6000_timer_int, 0,
				"timer", bvme6000_timer_int))
	panic ("Couldn't register timer int");

    rtc->t1cr_omr = 0x04;	/* Mode 2, ext clk */
    rtc->t1msb = 39999 >> 8;
    rtc->t1lsb = 39999 & 0xff;
    rtc->irr_icr1 &= 0xef;	/* Route timer 1 to INTR pin */
    rtc->msr = 0x40;		/* Access int.cntrl, etc */
    rtc->pfr_icr0 = 0x80;	/* Just timer 1 ints enabled */
    rtc->irr_icr1 = 0;
    rtc->t1cr_omr = 0x0a;	/* INTR+T1 active lo, push-pull */
    rtc->t0cr_rtmr &= 0xdf;	/* Stop timers in standby */
    rtc->msr = 0;		/* Access timer 1 control */
    rtc->t1cr_omr = 0x05;	/* Mode 2, ext clk, GO */

    rtc->msr = msr;

    if (request_irq(BVME_IRQ_ABORT, bvme6000_abort_int, 0,
				"abort", bvme6000_abort_int))
	panic ("Couldn't register abort int");
}


/* This is always executed with interrupts disabled.  */

/*
 * NOTE:  Don't accept any readings within 5us of rollover, as
 * the T1INT bit may be a little slow getting set.  There is also
 * a fault in the chip, meaning that reads may produce invalid
 * results...
 */

u32 bvme6000_gettimeoffset(void)
{
    volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
    volatile PitRegsPtr pit = (PitRegsPtr)BVME_PIT_BASE;
    unsigned char msr = rtc->msr & 0xc0;
    unsigned char t1int, t1op;
    u32 v = 800000, ov;

    rtc->msr = 0;	/* Ensure timer registers accessible */

    do {
	ov = v;
	t1int = rtc->msr & 0x20;
	t1op  = pit->pcdr & 0x04;
	rtc->t1cr_omr |= 0x40;		/* Latch timer1 */
	v = rtc->t1msb << 8;		/* Read timer1 */
	v |= rtc->t1lsb;		/* Read timer1 */
    } while (t1int != (rtc->msr & 0x20) ||
		t1op != (pit->pcdr & 0x04) ||
			abs(ov-v) > 80 ||
				v > 39960);

    v = 39999 - v;
    if (!t1op)				/* If in second half cycle.. */
	v += 40000;
    v /= 8;				/* Convert ticks to microseconds */
    if (t1int)
	v += 10000;			/* Int pending, + 10ms */
    rtc->msr = msr;

    return v * 1000;
}

/*
 * Looks like op is non-zero for setting the clock, and zero for
 * reading the clock.
 *
 *  struct hwclk_time {
 *         unsigned        sec;       0..59
 *         unsigned        min;       0..59
 *         unsigned        hour;      0..23
 *         unsigned        day;       1..31
 *         unsigned        mon;       0..11
 *         unsigned        year;      00...
 *         int             wday;      0..6, 0 is Sunday, -1 means unknown/don't set
 * };
 */

int bvme6000_hwclk(int op, struct rtc_time *t)
{
	volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
	unsigned char msr = rtc->msr & 0xc0;

	rtc->msr = 0x40;	/* Ensure clock and real-time-mode-register
				 * are accessible */
	if (op)
	{	/* Write.... */
		rtc->t0cr_rtmr = t->tm_year%4;
		rtc->bcd_tenms = 0;
		rtc->bcd_sec = bin2bcd(t->tm_sec);
		rtc->bcd_min = bin2bcd(t->tm_min);
		rtc->bcd_hr  = bin2bcd(t->tm_hour);
		rtc->bcd_dom = bin2bcd(t->tm_mday);
		rtc->bcd_mth = bin2bcd(t->tm_mon + 1);
		rtc->bcd_year = bin2bcd(t->tm_year%100);
		if (t->tm_wday >= 0)
			rtc->bcd_dow = bin2bcd(t->tm_wday+1);
		rtc->t0cr_rtmr = t->tm_year%4 | 0x08;
	}
	else
	{	/* Read....  */
		do {
			t->tm_sec  = bcd2bin(rtc->bcd_sec);
			t->tm_min  = bcd2bin(rtc->bcd_min);
			t->tm_hour = bcd2bin(rtc->bcd_hr);
			t->tm_mday = bcd2bin(rtc->bcd_dom);
			t->tm_mon  = bcd2bin(rtc->bcd_mth)-1;
			t->tm_year = bcd2bin(rtc->bcd_year);
			if (t->tm_year < 70)
				t->tm_year += 100;
			t->tm_wday = bcd2bin(rtc->bcd_dow)-1;
		} while (t->tm_sec != bcd2bin(rtc->bcd_sec));
	}

	rtc->msr = msr;

	return 0;
}

/*
 * Set the minutes and seconds from seconds value 'nowtime'.  Fail if
 * clock is out by > 30 minutes.  Logic lifted from atari code.
 * Algorithm is to wait for the 10ms register to change, and then to
 * wait a short while, and then set it.
 */

int bvme6000_set_clock_mmss (unsigned long nowtime)
{
	int retval = 0;
	short real_seconds = nowtime % 60, real_minutes = (nowtime / 60) % 60;
	unsigned char rtc_minutes, rtc_tenms;
	volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
	unsigned char msr = rtc->msr & 0xc0;
	unsigned long flags;
	volatile int i;

	rtc->msr = 0;		/* Ensure clock accessible */
	rtc_minutes = bcd2bin (rtc->bcd_min);

	if ((rtc_minutes < real_minutes
		? real_minutes - rtc_minutes
			: rtc_minutes - real_minutes) < 30)
	{
		local_irq_save(flags);
		rtc_tenms = rtc->bcd_tenms;
		while (rtc_tenms == rtc->bcd_tenms)
			;
		for (i = 0; i < 1000; i++)
			;
		rtc->bcd_min = bin2bcd(real_minutes);
		rtc->bcd_sec = bin2bcd(real_seconds);
		local_irq_restore(flags);
	}
	else
		retval = -1;

	rtc->msr = msr;

	return retval;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* arch/m68k/bvme6000/config.c
	3	*
	4	* Copyright (C) 1997 Richard Hirst [[email protected]]
	5	*
	6	* Based on:
	7	*
	8	* linux/amiga/config.c
	9	*
	10	* Copyright (C) 1993 Hamish Macdonald
	11	*
	12	* This file is subject to the terms and conditions of the GNU General Public
	13	* License. See the file README.legal in the main directory of this archive
	14	* for more details.
	15	*/
	16
	17	#include <linux/types.h>
	18	#include <linux/kernel.h>
	19	#include <linux/mm.h>
	20	#include <linux/tty.h>
	21	#include <linux/console.h>
	22	#include <linux/linkage.h>
	23	#include <linux/init.h>
	24	#include <linux/major.h>
	25	#include <linux/genhd.h>
	26	#include <linux/rtc.h>
	27	#include <linux/interrupt.h>
5b1d5f95	28	#include <linux/bcd.h>
1da177e4 LT	29
1da177e4 LT	30	#include <asm/bootinfo.h>
1da177e4 LT	31	#include <asm/pgtable.h>
	32	#include <asm/setup.h>
	33	#include <asm/irq.h>
	34	#include <asm/traps.h>
	35	#include <asm/rtc.h>
	36	#include <asm/machdep.h>
	37	#include <asm/bvme6000hw.h>
	38
1da177e4	39	static void bvme6000_get_model(char *model);
40220c1a	40	extern void bvme6000_sched_init(irq_handler_t handler);
c8d5ba18	41	extern u32 bvme6000_gettimeoffset(void);
1da177e4 LT	42	extern int bvme6000_hwclk (int, struct rtc_time *);
	43	extern int bvme6000_set_clock_mmss (unsigned long);
	44	extern void bvme6000_reset (void);
1da177e4 LT	45	void bvme6000_set_vectors (void);
1da177e4 LT	46
e53f276b TH	47	/* Save tick handler routine pointer, will point to xtime_update() in
e53f276b TH	48	* kernel/timer/timekeeping.c, called via bvme6000_process_int() */
1da177e4	49
40220c1a	50	static irq_handler_t tick_handler;
1da177e4 LT	51
	52
	53	int bvme6000_parse_bootinfo(const struct bi_record *bi)
	54	{
	55	if (bi->tag == BI_VME_TYPE)
	56	return 0;
	57	else
	58	return 1;
	59	}
	60
	61	void bvme6000_reset(void)
	62	{
	63	volatile PitRegsPtr pit = (PitRegsPtr)BVME_PIT_BASE;
	64
	65	printk ("\r\n\nCalled bvme6000_reset\r\n"
	66	"\r\r\r\r\r\r\r\r\r\r\r\r\r\r\r\r\r\r");
	67	/* The string of returns is to delay the reset until the whole
	68	* message is output. */
	69	/* Enable the watchdog, via PIT port C bit 4 */
	70
	71	pit->pcddr \|= 0x10; /* WDOG enable */
	72
	73	while(1)
	74	;
	75	}
	76
	77	static void bvme6000_get_model(char *model)
	78	{
	79	sprintf(model, "BVME%d000", m68k_cputype == CPU_68060 ? 6 : 4);
	80	}
	81
200a3d35 RZ	82	/*
	83	* This function is called during kernel startup to initialize
	84	* the bvme6000 IRQ handling routines.
	85	*/
66a3f820	86	static void __init bvme6000_init_IRQ(void)
200a3d35	87	{
f30a6484	88	m68k_setup_user_interrupt(VEC_USER, 192);
200a3d35	89	}
1da177e4 LT	90
	91	void __init config_bvme6000(void)
	92	{
	93	volatile PitRegsPtr pit = (PitRegsPtr)BVME_PIT_BASE;
	94
	95	/* Board type is only set by newer versions of vmelilo/tftplilo */
	96	if (!vme_brdtype) {
	97	if (m68k_cputype == CPU_68060)
	98	vme_brdtype = VME_TYPE_BVME6000;
	99	else
	100	vme_brdtype = VME_TYPE_BVME4000;
	101	}
	102	#if 0
	103	/* Call bvme6000_set_vectors() so ABORT will work, along with BVMBug
	104	* debugger. Note trap_init() will splat the abort vector, but
	105	* bvme6000_init_IRQ() will put it back again. Hopefully. */
	106
	107	bvme6000_set_vectors();
	108	#endif
	109
	110	mach_max_dma_address = 0xffffffff;
	111	mach_sched_init = bvme6000_sched_init;
	112	mach_init_IRQ = bvme6000_init_IRQ;
c8d5ba18	113	arch_gettimeoffset = bvme6000_gettimeoffset;
1da177e4 LT	114	mach_hwclk = bvme6000_hwclk;
	115	mach_set_clock_mmss = bvme6000_set_clock_mmss;
	116	mach_reset = bvme6000_reset;
1da177e4	117	mach_get_model = bvme6000_get_model;
1da177e4 LT	118
	119	printk ("Board is %sconfigured as a System Controller\n",
	120	*config_reg_ptr & BVME_CONFIG_SW1 ? "" : "not ");
	121
	122	/* Now do the PIT configuration */
	123
	124	pit->pgcr = 0x00; /* Unidirectional 8 bit, no handshake for now */
0b28002f	125	pit->psrr = 0x18; /* PIACK and PIRQ functions enabled */
1da177e4 LT	126	pit->pacr = 0x00; /* Sub Mode 00, H2 i/p, no DMA */
	127	pit->padr = 0x00; /* Just to be tidy! */
	128	pit->paddr = 0x00; /* All inputs for now (safest) */
	129	pit->pbcr = 0x80; /* Sub Mode 1x, H4 i/p, no DMA */
	130	pit->pbdr = 0xbc \| (*config_reg_ptr & BVME_CONFIG_SW1 ? 0 : 0x40);
	131	/* PRI, SYSCON?, Level3, SCC clks from xtal */
	132	pit->pbddr = 0xf3; /* Mostly outputs */
	133	pit->pcdr = 0x01; /* PA transceiver disabled */
	134	pit->pcddr = 0x03; /* WDOG disable */
	135
	136	/* Disable snooping for Ethernet and VME accesses */
	137
	138	bvme_acr_addrctl = 0;
	139	}
	140
	141
2850bc27	142	irqreturn_t bvme6000_abort_int (int irq, void *dev_id)
1da177e4 LT	143	{
	144	unsigned long new = (unsigned long )vectors;
	145	unsigned long old = (unsigned long )0xf8000000;
	146
	147	/* Wait for button release */
	148	while ((volatile unsigned char )BVME_LOCAL_IRQ_STAT & BVME_ABORT_STATUS)
	149	;
	150
	151	(new+4) = (old+4); /* Illegal instruction */
	152	(new+9) = (old+9); /* Trace */
	153	(new+47) = (old+47); /* Trap #15 */
	154	(new+0x1f) = (old+0x1f); /* ABORT switch */
	155	return IRQ_HANDLED;
	156	}
	157
	158
2850bc27	159	static irqreturn_t bvme6000_timer_int (int irq, void *dev_id)
1da177e4 LT	160	{
	161	volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
	162	unsigned char msr = rtc->msr & 0xc0;
	163
	164	rtc->msr = msr \| 0x20; /* Ack the interrupt */
	165
2850bc27	166	return tick_handler(irq, dev_id);
1da177e4 LT	167	}
	168
	169	/*
	170	* Set up the RTC timer 1 to mode 2, so T1 output toggles every 5ms
	171	* (40000 x 125ns). It will interrupt every 10ms, when T1 goes low.
	172	* So, when reading the elapsed time, you should read timer1,
	173	* subtract it from 39999, and then add 40000 if T1 is high.
	174	* That gives you the number of 125ns ticks in to the 10ms period,
	175	* so divide by 8 to get the microsecond result.
	176	*/
	177
40220c1a	178	void bvme6000_sched_init (irq_handler_t timer_routine)
1da177e4 LT	179	{
	180	volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
	181	unsigned char msr = rtc->msr & 0xc0;
	182
	183	rtc->msr = 0; /* Ensure timer registers accessible */
	184
	185	tick_handler = timer_routine;
	186	if (request_irq(BVME_IRQ_RTC, bvme6000_timer_int, 0,
	187	"timer", bvme6000_timer_int))
	188	panic ("Couldn't register timer int");
	189
	190	rtc->t1cr_omr = 0x04; /* Mode 2, ext clk */
	191	rtc->t1msb = 39999 >> 8;
	192	rtc->t1lsb = 39999 & 0xff;
	193	rtc->irr_icr1 &= 0xef; /* Route timer 1 to INTR pin */
	194	rtc->msr = 0x40; /* Access int.cntrl, etc */
	195	rtc->pfr_icr0 = 0x80; /* Just timer 1 ints enabled */
	196	rtc->irr_icr1 = 0;
	197	rtc->t1cr_omr = 0x0a; /* INTR+T1 active lo, push-pull */
	198	rtc->t0cr_rtmr &= 0xdf; /* Stop timers in standby */
	199	rtc->msr = 0; /* Access timer 1 control */
	200	rtc->t1cr_omr = 0x05; /* Mode 2, ext clk, GO */
	201
	202	rtc->msr = msr;
	203
	204	if (request_irq(BVME_IRQ_ABORT, bvme6000_abort_int, 0,
	205	"abort", bvme6000_abort_int))
	206	panic ("Couldn't register abort int");
	207	}
	208
	209
	210	/* This is always executed with interrupts disabled. */
	211
	212	/*
	213	* NOTE: Don't accept any readings within 5us of rollover, as
	214	* the T1INT bit may be a little slow getting set. There is also
	215	* a fault in the chip, meaning that reads may produce invalid
	216	* results...
	217	*/
	218
c8d5ba18	219	u32 bvme6000_gettimeoffset(void)
1da177e4 LT	220	{
	221	volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
	222	volatile PitRegsPtr pit = (PitRegsPtr)BVME_PIT_BASE;
	223	unsigned char msr = rtc->msr & 0xc0;
	224	unsigned char t1int, t1op;
c8d5ba18	225	u32 v = 800000, ov;
1da177e4 LT	226
	227	rtc->msr = 0; /* Ensure timer registers accessible */
	228
	229	do {
	230	ov = v;
	231	t1int = rtc->msr & 0x20;
	232	t1op = pit->pcdr & 0x04;
	233	rtc->t1cr_omr \|= 0x40; /* Latch timer1 */
	234	v = rtc->t1msb << 8; /* Read timer1 */
	235	v \|= rtc->t1lsb; /* Read timer1 */
	236	} while (t1int != (rtc->msr & 0x20) \|\|
	237	t1op != (pit->pcdr & 0x04) \|\|
	238	abs(ov-v) > 80 \|\|
	239	v > 39960);
	240
	241	v = 39999 - v;
	242	if (!t1op) /* If in second half cycle.. */
	243	v += 40000;
	244	v /= 8; /* Convert ticks to microseconds */
	245	if (t1int)
	246	v += 10000; /* Int pending, + 10ms */
	247	rtc->msr = msr;
	248
c8d5ba18	249	return v * 1000;
1da177e4 LT	250	}
1da177e4 LT	251
1da177e4 LT	252	/*
	253	* Looks like op is non-zero for setting the clock, and zero for
	254	* reading the clock.
	255	*
	256	* struct hwclk_time {
	257	* unsigned sec; 0..59
	258	* unsigned min; 0..59
	259	* unsigned hour; 0..23
	260	* unsigned day; 1..31
	261	* unsigned mon; 0..11
	262	* unsigned year; 00...
	263	* int wday; 0..6, 0 is Sunday, -1 means unknown/don't set
	264	* };
	265	*/
	266
	267	int bvme6000_hwclk(int op, struct rtc_time *t)
	268	{
	269	volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
	270	unsigned char msr = rtc->msr & 0xc0;
	271
	272	rtc->msr = 0x40; /* Ensure clock and real-time-mode-register
	273	* are accessible */
	274	if (op)
	275	{ /* Write.... */
	276	rtc->t0cr_rtmr = t->tm_year%4;
	277	rtc->bcd_tenms = 0;
	278	rtc->bcd_sec = bin2bcd(t->tm_sec);
	279	rtc->bcd_min = bin2bcd(t->tm_min);
	280	rtc->bcd_hr = bin2bcd(t->tm_hour);
	281	rtc->bcd_dom = bin2bcd(t->tm_mday);
	282	rtc->bcd_mth = bin2bcd(t->tm_mon + 1);
	283	rtc->bcd_year = bin2bcd(t->tm_year%100);
	284	if (t->tm_wday >= 0)
	285	rtc->bcd_dow = bin2bcd(t->tm_wday+1);
	286	rtc->t0cr_rtmr = t->tm_year%4 \| 0x08;
	287	}
	288	else
	289	{ /* Read.... */
	290	do {
	291	t->tm_sec = bcd2bin(rtc->bcd_sec);
	292	t->tm_min = bcd2bin(rtc->bcd_min);
	293	t->tm_hour = bcd2bin(rtc->bcd_hr);
	294	t->tm_mday = bcd2bin(rtc->bcd_dom);
	295	t->tm_mon = bcd2bin(rtc->bcd_mth)-1;
	296	t->tm_year = bcd2bin(rtc->bcd_year);
	297	if (t->tm_year < 70)
	298	t->tm_year += 100;
	299	t->tm_wday = bcd2bin(rtc->bcd_dow)-1;
	300	} while (t->tm_sec != bcd2bin(rtc->bcd_sec));
	301	}
	302
	303	rtc->msr = msr;
	304
	305	return 0;
	306	}
	307
	308	/*
	309	* Set the minutes and seconds from seconds value 'nowtime'. Fail if
	310	* clock is out by > 30 minutes. Logic lifted from atari code.
	311	* Algorithm is to wait for the 10ms register to change, and then to
	312	* wait a short while, and then set it.
	313	*/
	314
	315	int bvme6000_set_clock_mmss (unsigned long nowtime)
316	{
317	int retval = 0;
318	short real_seconds = nowtime % 60, real_minutes = (nowtime / 60) % 60;
319	unsigned char rtc_minutes, rtc_tenms;
320	volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
321	unsigned char msr = rtc->msr & 0xc0;
322	unsigned long flags;
323	volatile int i;
324
325	rtc->msr = 0; /* Ensure clock accessible */
326	rtc_minutes = bcd2bin (rtc->bcd_min);
327
328	if ((rtc_minutes < real_minutes
329	? real_minutes - rtc_minutes
330	: rtc_minutes - real_minutes) < 30)
331	{
332	local_irq_save(flags);
333	rtc_tenms = rtc->bcd_tenms;
334	while (rtc_tenms == rtc->bcd_tenms)
335	;
336	for (i = 0; i < 1000; i++)
337	;
338	rtc->bcd_min = bin2bcd(real_minutes);
339	rtc->bcd_sec = bin2bcd(real_seconds);
340	local_irq_restore(flags);
341	}
342	else
343	retval = -1;
344
345	rtc->msr = msr;
346
347	return retval;
348	}
349