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Kernel: Prefer 32 bit HPET timers on 32 bit target

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Bananymous
2026-08-22 13:23:43 +03:00
parent 0d6b32dc3c
commit 67fdd24a19
1 changed files with 27 additions and 16 deletions
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kernel/kernel/Timer/HPET.cpp
+27 -16
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@@ -197,17 +197,36 @@ namespace Kernel
return BAN::Error::from_errno(ENOTSUP);
}
// set timer period to 1000 Hz
const uint64_t ticks_per_ms = m_ticks_per_s / 1000;
#if ARCH(x86_64)
const bool use_64bit_timer = !!(timer0.configuration & Tn_SIZE_CAP);
#else
// Spec recommends using 32 bit timers when the cpu can't do atomic 64 bit accesses
const bool use_64bit_timer = !!(timer0.configuration & Tn_SIZE_CAP) && (ticks_per_ms > 0xFFFFFFFF);
#endif
if (!use_64bit_timer && ticks_per_ms >= 0x100000000)
{
dprintln("HPET: cannot create 1 kHz timer");
return BAN::Error::from_errno(ENOTSUP);
}
// enable interrupts
timer0.configuration = timer0.configuration | Tn_INT_ENB_CNF;
timer0.configuration |= Tn_INT_ENB_CNF;
// edge triggered interrupts
timer0.configuration = timer0.configuration & ~Tn_INT_TYPE_CNF;
timer0.configuration &= ~Tn_INT_TYPE_CNF;
// periodic timer
timer0.configuration = timer0.configuration | Tn_TYPE_CNF;
// disable 32 bit mode
timer0.configuration = timer0.configuration & ~Tn_32MODE_CNF;
timer0.configuration |= Tn_TYPE_CNF;
// set 32 bit mode
if (use_64bit_timer)
timer0.configuration &= ~Tn_32MODE_CNF;
else
timer0.configuration |= Tn_32MODE_CNF;
// disable FSB interrupts
if (timer0.configuration & Tn_FSB_INT_DEL_CAP)
timer0.configuration = timer0.configuration & ~Tn_FSB_EN_CNF;
timer0.configuration &= ~Tn_FSB_EN_CNF;
uint16_t irq;
if (header->legacy_replacement_irq_routing_cable)
@@ -244,10 +263,7 @@ namespace Kernel
timer0.configuration = (timer0.configuration & ~Tn_INT_ROUTE_CNF_MASK) | (gsi << Tn_INT_ROUTE_CNF_SHIFT);
}
// set timer period to 1000 Hz
const uint64_t ticks_per_ms = m_ticks_per_s / 1000;
if (timer0.configuration & Tn_SIZE_CAP)
if (use_64bit_timer)
{
#if ARCH(x86_64)
timer0.configuration = timer0.configuration | Tn_VAL_SET_CNF;
@@ -259,16 +275,11 @@ namespace Kernel
timer0.comparator.high = ticks_per_ms >> 32;
#endif
}
else if (ticks_per_ms <= 0xFFFFFFFF)
else
{
timer0.configuration = timer0.configuration | Tn_VAL_SET_CNF;
timer0.comparator.low = ticks_per_ms;
}
else
{
dprintln("HPET: cannot create 1 kHz timer");
return BAN::Error::from_errno(ENOTSUP);
}
set_irq(irq);
InterruptController::get().enable_irq(irq);