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* Put the calibration loop into a static inline function and replace the three

Browse Source 
copies of it with a call to that.
* Make the variable names more readable and spacing cleanup.

No functional change intended.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@41670 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Michael Lotz 2011-05-23 11:15:51 +00:00
parent d620303480
commit 34d3f13c64
1 changed files with 69 additions and 75 deletions
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144
src/system/boot/platform/bios_ia32/cpu.cpp
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@ -173,16 +173,46 @@ private:
};
static inline void
calibration_loop(uint8 desiredHighByte, uint8 channel, uint64& tscDelta,
double& conversionFactor, uint16& expired)
{
uint8 select = channel << PIT_SELECT_CHANNEL_SHIFT;
uint8 channelPort = PIT_CHANNEL_PORT_BASE + channel;
// Wait for the PIT to arrive at our starting position (high byte == 0xff)
uint8 startLow;
uint8 startHigh;
do {
out8(select | PIT_ACCESS_LATCH_COUNTER, PIT_CONTROL);
startLow = in8(channelPort);
startHigh = in8(channelPort);
} while (startHigh != 255);
// Read in the first TSC value
uint64 startTSC = rdtsc();
// Wait for the PIT to count down to our desired value
uint8 endLow;
uint8 endHigh;
do {
out8(select | PIT_ACCESS_LATCH_COUNTER, PIT_CONTROL);
endLow = in8(channelPort);
endHigh = in8(channelPort);
} while (endHigh > desiredHighByte);
// And read the second TSC value
uint64 endTSC = rdtsc();
tscDelta = endTSC - startTSC;
expired = ((startHigh << 8) | startLow) - ((endHigh << 8) | endLow);
conversionFactor = (double)tscDelta / (double)expired;
}
static void
calculate_cpu_conversion_factor()
{
uint32 s_low, s_high;
uint32 low, high;
uint32 expired;
uint64 t1, t2;
uint64 p1, p2, p3;
double r1, r2, r3;
uint8 channel = 0;
uint8 channelPort = PIT_CHANNEL_PORT_BASE + channel;
uint8 control;
@ -204,90 +234,54 @@ calculate_cpu_conversion_factor()
out8(0xff, channelPort);
out8(0xff, channelPort);
/* quick sample */
uint64 tscDeltaQuick, tscDeltaSlower, tscDeltaSlow;
double conversionFactorQuick, conversionFactorSlower, conversionFactorSlow;
uint16 expired;
quick_sample:
do {
out8(select | PIT_ACCESS_LATCH_COUNTER, PIT_CONTROL);
s_low = in8(channelPort);
s_high = in8(channelPort);
} while (s_high != 255);
t1 = rdtsc();
do {
out8(select | PIT_ACCESS_LATCH_COUNTER, PIT_CONTROL);
low = in8(channelPort);
high = in8(channelPort);
} while (high > 224);
t2 = rdtsc();
calibration_loop(224, channel, tscDeltaQuick, conversionFactorQuick,
expired);
p1 = t2-t1;
r1 = (double)(p1) / (double)(((s_high << 8) | s_low) - ((high << 8) | low));
slower_sample:
calibration_loop(192, channel, tscDeltaSlower, conversionFactorSlower,
expired);
/* not so quick sample */
not_so_quick_sample:
do {
out8(select | PIT_ACCESS_LATCH_COUNTER, PIT_CONTROL);
s_low = in8(channelPort);
s_high = in8(channelPort);
} while (s_high != 255);
t1 = rdtsc();
do {
out8(select | PIT_ACCESS_LATCH_COUNTER, PIT_CONTROL);
low = in8(channelPort);
high = in8(channelPort);
} while (high > 192);
t2 = rdtsc();
p2 = t2-t1;
r2 = (double)(p2) / (double)(((s_high << 8) | s_low) - ((high << 8) | low));
if ((r1/r2) > 1.01) {
//dprintf("Tuning loop(1)\n");
goto quick_sample;
}
if ((r1/r2) < 0.99) {
//dprintf("Tuning loop(1)\n");
double deviation = conversionFactorQuick / conversionFactorSlower;
if (deviation < 0.99 || deviation > 1.01) {
// We might have been hit by a SMI or were otherwise stalled
goto quick_sample;
}
/* slow sample */
do {
out8(select | PIT_ACCESS_LATCH_COUNTER, PIT_CONTROL);
s_low = in8(channelPort);
s_high = in8(channelPort);
} while (s_high != 255);
t1 = rdtsc();
do {
out8(select | PIT_ACCESS_LATCH_COUNTER, PIT_CONTROL);
low = in8(channelPort);
high = in8(channelPort);
} while (high > 128);
t2 = rdtsc();
// Slow sample
calibration_loop(128, channel, tscDeltaSlow, conversionFactorSlow,
expired);
p3 = t2-t1;
r3 = (double)(p3) / (double)(((s_high << 8) | s_low) - ((high << 8) | low));
if ((r2/r3) > 1.01) {
TRACE(("Tuning loop(2)\n"));
goto not_so_quick_sample;
}
if ((r2/r3) < 0.99) {
TRACE(("Tuning loop(2)\n"));
goto not_so_quick_sample;
deviation = conversionFactorSlower / conversionFactorSlow;
if (deviation < 0.99 || deviation > 1.01) {
// We might have been hit by a SMI or were otherwise stalled
goto slower_sample;
}
expired = ((s_high << 8) | s_low) - ((high << 8) | low);
p3 *= TIMER_CLKNUM_HZ;
// Scale the TSC delta to timer units
tscDeltaSlow *= TIMER_CLKNUM_HZ;
uint64 clockSpeed = tscDeltaSlow / expired;
gTimeConversionFactor = ((uint128(expired) * uint32(1000000)) << 32)
/ uint128(p3);
/ uint128(tscDeltaSlow);
#ifdef TRACE_CPU
if (p3 / expired / 1000000000LL)
dprintf("CPU at %Ld.%03Ld GHz\n", p3/expired/1000000000LL, ((p3/expired)%1000000000LL)/1000000LL);
else
dprintf("CPU at %Ld.%03Ld MHz\n", p3/expired/1000000LL, ((p3/expired)%1000000LL)/1000LL);
if (clockSpeed > 1000000000LL) {
dprintf("CPU at %Ld.%03Ld GHz\n", clockSpeed / 1000000000LL,
(clockSpeed % 1000000000LL) / 1000000LL);
} else {
dprintf("CPU at %Ld.%03Ld MHz\n", clockSpeed / 1000000LL,
(clockSpeed % 1000000LL) / 1000LL);
}
#endif
gKernelArgs.arch_args.system_time_cv_factor = gTimeConversionFactor;
gKernelArgs.arch_args.cpu_clock_speed = p3 / expired;
//dprintf("factors: %lu %llu\n", gTimeConversionFactor, p3 / expired);
gKernelArgs.arch_args.cpu_clock_speed = clockSpeed;
//dprintf("factors: %lu %llu\n", gTimeConversionFactor, clockSpeed);
}