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s3c2800_clk.c revision 1.9 
      1 /* $NetBSD: s3c2800_clk.c,v 1.9 2005/12/24 20:06:52 perry Exp $ */
      2 
      3 /*
      4  * Copyright (c) 2002 Fujitsu Component Limited
      5  * Copyright (c) 2002 Genetec Corporation
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. Neither the name of The Fujitsu Component Limited nor the name of
     17  *    Genetec corporation may not be used to endorse or promote products
     18  *    derived from this software without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY FUJITSU COMPONENT LIMITED AND GENETEC
     21  * CORPORATION ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
     22  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     23  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     24  * DISCLAIMED.  IN NO EVENT SHALL FUJITSU COMPONENT LIMITED OR GENETEC
     25  * CORPORATION BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     27  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
     28  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     29  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 
     36 #include <sys/cdefs.h>
     37 __KERNEL_RCSID(0, "$NetBSD: s3c2800_clk.c,v 1.9 2005/12/24 20:06:52 perry Exp $");
     38 
     39 #include <sys/param.h>
     40 #include <sys/systm.h>
     41 #include <sys/kernel.h>
     42 #include <sys/time.h>
     43 
     44 #include <machine/bus.h>
     45 #include <machine/intr.h>
     46 #include <arm/cpufunc.h>
     47 
     48 #include <arm/s3c2xx0/s3c2800reg.h>
     49 #include <arm/s3c2xx0/s3c2800var.h>
     50 
     51 
     52 #ifndef STATHZ
     53 #define STATHZ	64
     54 #endif
     55 
     56 #define TIMER_FREQUENCY(pclk) ((pclk)/32) /* divider=1/32 */
     57 
     58 static unsigned int timer0_reload_value;
     59 static unsigned int timer0_prescaler;
     60 static unsigned int timer0_mseccount;
     61 
     62 #define usec_to_counter(t)	\
     63 	((timer0_mseccount*(t))/1000)
     64 
     65 #define counter_to_usec(c,pclk)	\
     66 	(((c)*timer0_prescaler*1000)/(TIMER_FREQUENCY(pclk)/1000))
     67 
     68 /*
     69  * microtime:
     70  *
     71  *	Fill in the specified timeval struct with the current time
     72  *	accurate to the microsecond.
     73  */
     74 void
     75 microtime(struct timeval *tvp)
     76 {
     77 	struct s3c2800_softc *sc = (struct s3c2800_softc *) s3c2xx0_softc;
     78 	int save, int_pend0, int_pend1, count, delta;
     79 	static struct timeval last;
     80 	int pclk = s3c2xx0_softc->sc_pclk;
     81 
     82 	if( timer0_reload_value == 0 ){
     83 		/* not initialized yet */
     84 		tvp->tv_sec = 0;
     85 		tvp->tv_usec = 0;
     86 		return;
     87 	}
     88 
     89 	save = disable_interrupts(I32_bit);
     90 
     91  again:
     92 	int_pend0 = S3C2800_INT_TIMER0 &
     93 	    bus_space_read_4(sc->sc_sx.sc_iot, sc->sc_sx.sc_intctl_ioh,
     94 		INTCTL_SRCPND);
     95 	count = bus_space_read_2(sc->sc_sx.sc_iot, sc->sc_tmr0_ioh,
     96 	    TIMER_TMCNT);
     97 
     98 	for (;;){
     99 
    100 		int_pend1 = S3C2800_INT_TIMER0 &
    101 		    bus_space_read_4(sc->sc_sx.sc_iot, sc->sc_sx.sc_intctl_ioh,
    102 			INTCTL_SRCPND);
    103 		if( int_pend0 == int_pend1 )
    104 			break;
    105 
    106 		/*
    107 		 * Down counter reached to zero while we were reading
    108 		 * timer values. do it again to get consistent values.
    109 		 */
    110 		int_pend0 = int_pend1;
    111 		count = bus_space_read_2(sc->sc_sx.sc_iot, sc->sc_tmr0_ioh,
    112 		    TIMER_TMCNT);
    113 	}
    114 
    115 	if( __predict_false(count > timer0_reload_value) ){
    116 		/*
    117 		 * Buggy Hardware Warning --- sometimes timer counter
    118 		 * reads bogus value like 0xffff.  I guess it happens when
    119 		 * the timer is reloaded.
    120 		 */
    121 #if 0
    122 		printf( "Bogus value from timer counter: %d\n", count );
    123 #endif
    124 		goto again;
    125 	}
    126 
    127 	/* copy system time */
    128 	*tvp = time;
    129 
    130 	restore_interrupts(save);
    131 
    132 	delta = timer0_reload_value - count;
    133 
    134 	if( int_pend1 ){
    135 		/*
    136 		 * down counter underflow, but
    137 		 * clock interrupt have not serviced yet
    138 		 */
    139 #if 1
    140 		tvp->tv_usec += tick;
    141 #else
    142 		delta = 0;
    143 #endif
    144 	}
    145 
    146 	tvp->tv_usec += counter_to_usec(delta, pclk);
    147 
    148 	/* Make sure microseconds doesn't overflow. */
    149 	tvp->tv_sec += tvp->tv_usec / 1000000;
    150 	tvp->tv_usec = tvp->tv_usec % 1000000;
    151 
    152 	if (last.tv_sec &&
    153 	    (tvp->tv_sec < last.tv_sec ||
    154 		(tvp->tv_sec == last.tv_sec &&
    155 		    tvp->tv_usec < last.tv_usec) ) ){
    156 
    157 		/* XXX: This happens very often when the kernel runs
    158 		   under Multi-ICE */
    159 #if 0
    160 		printf("time reversal: %ld.%06ld(%d,%d) -> %ld.%06ld(%d,%d)\n",
    161 		    last.tv_sec, last.tv_usec,
    162 		    last_count, last_pend,
    163 		    tvp->tv_sec, tvp->tv_usec,
    164 		    count, int_pend1 );
    165 #endif
    166 
    167 		/* make sure the time has advanced. */
    168 		*tvp = last;
    169 		tvp->tv_usec++;
    170 		if( tvp->tv_usec >= 1000000 ){
    171 			tvp->tv_usec -= 1000000;
    172 			tvp->tv_sec++;
    173 		}
    174 	}
    175 
    176 	last = *tvp;
    177 }
    178 
    179 static inline int
    180 read_timer(struct s3c2800_softc *sc)
    181 {
    182 	int count;
    183 
    184 	do {
    185 		count = bus_space_read_2(sc->sc_sx.sc_iot, sc->sc_tmr0_ioh,
    186 		    TIMER_TMCNT);
    187 	} while ( __predict_false(count > timer0_reload_value) );
    188 
    189 	return count;
    190 }
    191 
    192 /*
    193  * delay:
    194  *
    195  *	Delay for at least N microseconds.
    196  */
    197 void
    198 delay(u_int n)
    199 {
    200 	struct s3c2800_softc *sc = (struct s3c2800_softc *) s3c2xx0_softc;
    201 	int v0, v1, delta;
    202 	u_int ucnt;
    203 
    204 	if ( timer0_reload_value == 0 ){
    205 		/* not initialized yet */
    206 		while ( n-- > 0 ){
    207 			int m;
    208 
    209 			for (m=0; m<100; ++m )
    210 				;
    211 		}
    212 		return;
    213 	}
    214 
    215 	/* read down counter */
    216 	v0 = read_timer(sc);
    217 
    218 	ucnt = usec_to_counter(n);
    219 
    220 	while( ucnt > 0 ) {
    221 		v1 = read_timer(sc);
    222 		delta = v0 - v1;
    223 		if ( delta < 0 )
    224 			delta += timer0_reload_value;
    225 #ifdef DEBUG
    226 		if (delta < 0 || delta > timer0_reload_value)
    227 			panic("wrong value from timer counter");
    228 #endif
    229 
    230 		if((u_int)delta < ucnt){
    231 			ucnt -= (u_int)delta;
    232 			v0 = v1;
    233 		}
    234 		else {
    235 			ucnt = 0;
    236 		}
    237 	}
    238 	/*NOTREACHED*/
    239 }
    240 
    241 /*
    242  * inittodr:
    243  *
    244  *	Initialize time from the time-of-day register.
    245  */
    246 void
    247 inittodr(time_t base)
    248 {
    249 
    250 	time.tv_sec = base;
    251 	time.tv_usec = 0;
    252 }
    253 
    254 /*
    255  * resettodr:
    256  *
    257  *	Reset the time-of-day register with the current time.
    258  */
    259 void
    260 resettodr(void)
    261 {
    262 }
    263 
    264 void
    265 setstatclockrate(int newhz)
    266 {
    267 }
    268 
    269 
    270 #define hardintr	(int (*)(void *))hardclock
    271 #define statintr	(int (*)(void *))statclock
    272 
    273 void
    274 cpu_initclocks()
    275 {
    276 	struct s3c2800_softc *sc = (struct s3c2800_softc *)s3c2xx0_softc;
    277 	long tc;
    278 	int prescaler;
    279 	int pclk = s3c2xx0_softc->sc_pclk;
    280 
    281 	stathz = STATHZ;
    282 	profhz = stathz;
    283 
    284 #define calc_time_constant(hz)					\
    285 	do {							\
    286 		prescaler = 1;					\
    287 		do {						\
    288 			++prescaler;				\
    289 			tc = TIMER_FREQUENCY(pclk) /(hz)/ prescaler;	\
    290 		} while( tc > 65536 );				\
    291 	} while(0)
    292 
    293 
    294 
    295 	/* Use the channels 0 and 1 for hardclock and statclock, respectively */
    296 	bus_space_write_4(sc->sc_sx.sc_iot, sc->sc_tmr0_ioh, TIMER_TMCON, 0);
    297 	bus_space_write_4(sc->sc_sx.sc_iot, sc->sc_tmr1_ioh, TIMER_TMCON, 0);
    298 
    299 	calc_time_constant(hz);
    300 	bus_space_write_4(sc->sc_sx.sc_iot, sc->sc_tmr0_ioh, TIMER_TMDAT,
    301 	    ((prescaler - 1) << 16) | (tc - 1));
    302 	timer0_prescaler = prescaler;
    303 	timer0_reload_value = tc;
    304 	timer0_mseccount = TIMER_FREQUENCY(pclk)/timer0_prescaler/1000 ;
    305 
    306 	printf("clock: hz=%d stathz = %d PCLK=%d prescaler=%d tc=%ld\n",
    307 	    hz, stathz, pclk, prescaler, tc);
    308 
    309 	calc_time_constant(stathz);
    310 	bus_space_write_4(sc->sc_sx.sc_iot, sc->sc_tmr1_ioh, TIMER_TMDAT,
    311 	    ((prescaler - 1) << 16) | (tc - 1));
    312 
    313 
    314 	s3c2800_intr_establish(S3C2800_INT_TIMER0, IPL_CLOCK,
    315 			       IST_NONE, hardintr, 0);
    316 	s3c2800_intr_establish(S3C2800_INT_TIMER1, IPL_STATCLOCK,
    317 			       IST_NONE, statintr, 0);
    318 
    319 	/* start timers */
    320 	bus_space_write_4(sc->sc_sx.sc_iot, sc->sc_tmr0_ioh, TIMER_TMCON,
    321 	    TMCON_MUX_DIV32|TMCON_INTENA|TMCON_ENABLE);
    322 	bus_space_write_4(sc->sc_sx.sc_iot, sc->sc_tmr1_ioh, TIMER_TMCON,
    323 	    TMCON_MUX_DIV4|TMCON_INTENA|TMCON_ENABLE);
    324 
    325 	/* stop timer2 */
    326 	{
    327 		bus_space_handle_t tmp_ioh;
    328 
    329 		bus_space_map(sc->sc_sx.sc_iot, S3C2800_TIMER2_BASE,
    330 		    S3C2800_TIMER_SIZE, 0, &tmp_ioh);
    331 
    332 		bus_space_write_4(sc->sc_sx.sc_iot, tmp_ioh,
    333 		    TIMER_TMCON, 0);
    334 
    335 		bus_space_unmap(sc->sc_sx.sc_iot, tmp_ioh,
    336 		    S3C2800_TIMER_SIZE);
    337 
    338 	}
    339 }
    340