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#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "ureg.h"
#include "../port/error.h"
enum {
RTCREGS = 0x90010000, /* real time clock registers */
RTSR_al = 0x01, /* alarm detected */
RTSR_hz = 0x02, /* 1Hz tick */
RTSR_ale= 0x04, /* alarm interrupt enable */
RTSR_hze= 0x08, /* 1Hz tick enable */
Never = 0xffffffff,
};
typedef struct OSTimer
{
ulong osmr[4]; /* match registers */
volatile ulong oscr; /* counter register */
ulong ossr; /* status register */
ulong ower; /* watchdog enable register */
ulong oier; /* timer interrupt enable register */
} OSTimer;
typedef struct RTCregs
{
ulong rtar; /* alarm */
ulong rcnr; /* count */
ulong rttr; /* trim */
ulong dummy; /* hole */
ulong rtsr; /* status */
} RTCregs;
OSTimer *timerregs = (OSTimer*)OSTIMERREGS;
RTCregs *rtcregs = (RTCregs*)RTCREGS;
static int clockinited;
static void clockintr(Ureg*, void*);
static void rtcintr(Ureg*, void*);
static Tval when; /* scheduled time of next interrupt */
long timeradjust;
enum
{
Minfreq = ClockFreq/HZ, /* At least one interrupt per HZ (50 ms) */
Maxfreq = ClockFreq/10000, /* At most one interrupt every 100 µs */
};
ulong
clockpower(int on)
{
static ulong savedtime;
if (on){
timerregs->ossr |= 1<<0;
timerregs->oier = 1<<0;
timerregs->osmr[0] = timerregs->oscr + Minfreq;
if (rtcregs->rttr == 0){
rtcregs->rttr = 0x8000; // nominal frequency.
rtcregs->rcnr = 0;
rtcregs->rtar = 0xffffffff;
rtcregs->rtsr |= RTSR_ale;
rtcregs->rtsr |= RTSR_hze;
}
if (rtcregs->rcnr > savedtime)
return rtcregs->rcnr - savedtime;
} else
savedtime = rtcregs->rcnr;
clockinited = on;
return 0L;
}
void
clockinit(void)
{
ulong x;
ulong id;
/* map the clock registers */
timerregs = mapspecial(OSTIMERREGS, sizeof(OSTimer));
rtcregs = mapspecial(RTCREGS, sizeof(RTCregs));
/* enable interrupts on match register 0, turn off all others */
timerregs->ossr |= 1<<0;
intrenable(IRQ, IRQtimer0, clockintr, nil, "clock");
timerregs->oier = 1<<0;
/* figure out processor frequency */
x = powerregs->ppcr & 0x1f;
conf.hz = ClockFreq*(x*4+16);
conf.mhz = (conf.hz+499999)/1000000;
/* get processor type */
id = getcpuid();
print("%lud MHZ ARM, ver %lux/part %lux/step %lud\n", conf.mhz,
(id>>16)&0xff, (id>>4)&0xfff, id&0xf);
/* post interrupt 1/HZ secs from now */
when = timerregs->oscr + Minfreq;
timerregs->osmr[0] = when;
/* enable RTC interrupts and alarms */
intrenable(IRQ, IRQrtc, rtcintr, nil, "rtc");
rtcregs->rttr = 0x8000; // make rcnr 1Hz
rtcregs->rcnr = 0; // reset counter
rtcregs->rtsr |= RTSR_al;
rtcregs->rtsr |= RTSR_ale;
timersinit();
clockinited = 1;
}
/* turn 32 bit counter into a 64 bit one. since todfix calls
* us at least once a second and we overflow once every 1165
* seconds, we won't miss an overflow.
*/
uvlong
fastticks(uvlong *hz)
{
static uvlong high;
static ulong last;
ulong x;
if(hz != nil)
*hz = ClockFreq;
x = timerregs->oscr;
if(x < last)
high += 1LL<<32;
last = x;
return high+x;
}
ulong
µs(void)
{
return fastticks2us(fastticks(nil));
}
void
timerset(Tval v)
{
ulong next, tics; /* Must be unsigned! */
static int count;
next = v;
/* post next interrupt: calculate # of tics from now */
tics = next - timerregs->oscr - Maxfreq;
if (tics > Minfreq){
timeradjust++;
next = timerregs->oscr + Maxfreq;
}
timerregs->osmr[0] = next;
}
static void
clockintr(Ureg *ureg, void*)
{
/* reset previous interrupt */
timerregs->ossr |= 1<<0;
when += Minfreq;
timerregs->osmr[0] = when; /* insurance */
timerintr(ureg, when);
}
void
rtcalarm(ulong secs)
{
vlong t;
if (t == 0){
iprint("RTC alarm cancelled\n");
rtcregs->rtsr &= ~RTSR_ale;
rtcregs->rtar = 0xffffffff;
} else {
t = todget(nil);
t = t / 1000000000ULL; // nsec to secs
if (secs < t)
return;
secs -= t;
iprint("RTC alarm set to %uld seconds from now\n", secs);
rtcregs->rtar = rtcregs->rcnr + secs;
rtcregs->rtsr|= RTSR_ale;
}
}
static void
rtcintr(Ureg*, void*)
{
/* reset interrupt */
rtcregs->rtsr&= ~RTSR_ale;
rtcregs->rtsr&= ~RTSR_al;
rtcregs->rtar = 0;
iprint("RTC alarm: %lud\n", rtcregs->rcnr);
}
void
delay(int ms)
{
ulong start;
int i;
if(clockinited){
while(ms-- > 0){
start = timerregs->oscr;
while(timerregs->oscr-start < ClockFreq/1000)
;
}
} else {
while(ms-- > 0){
for(i = 0; i < 1000; i++)
;
}
}
}
void
microdelay(int µs)
{
ulong start;
int i;
µs++;
if(clockinited){
start = timerregs->oscr;
while(timerregs->oscr - start < 1UL+(µs*ClockFreq)/1000000UL)
;
} else {
while(µs-- > 0){
for(i = 0; i < 10; i++)
;
}
}
}
/*
* performance measurement ticks. must be low overhead.
* doesn't have to count over a second.
*/
ulong
perfticks(void)
{
return timerregs->oscr;
}
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