+/*
+ * Acess2 Kernel
+ * Timekeeping
+ * arch/x86_64/time.c
+ */
+#include <acess.h>
+
+// === MACROS ===
+#define TIMER_QUANTUM 100
+// 2^(15-rate), 15: 1HZ, 5: 1024Hz, 2: 8192Hz
+// (Max: 15, Min: 2) - 15 = 1Hz, 13 = 4Hz, 12 = 8Hz, 11 = 16Hz 10 = 32Hz, 2 = 8192Hz
+//#define TIMER_RATE 10 // 32 Hz
+//#define TIMER_RATE 12 // 8 Hz
+#define TIMER_RATE 14 // 2Hz
+//#define TIMER_RATE 15 // 1HZ
+#define TIMER_FREQ (0x8000>>TIMER_RATE) //Hz
+#define MS_PER_TICK_WHOLE (1000/(TIMER_FREQ))
+#define MS_PER_TICK_FRACT ((0x80000000*(1000%TIMER_FREQ))/TIMER_FREQ)
+
+// === IMPORTS ===
+extern volatile Sint64 giTimestamp;
+extern volatile Uint64 giTicks;
+extern volatile Uint64 giPartMiliseconds;
+extern void Timer_CallTimers(void);
+
+// === GLOBALS ===
+volatile Uint64 giTime_TSCAtLastTick = 0;
+volatile Uint64 giTime_TSCPerTick = 0;
+
+// === PROTOTYPES ===
+Sint64 now(void);
+ int Time_Setup(void);
+void Time_Interrupt(int);
+Uint64 Time_ReadTSC(void);
+
+// === CODE ===
+/**
+ * \fn Sint64 now()
+ * \brief Return the current timestamp
+ */
+Sint64 now(void)
+{
+ Uint64 tsc = Time_ReadTSC();
+ tsc -= giTime_TSCAtLastTick;
+ tsc *= MS_PER_TICK_WHOLE;
+ if( giTime_TSCPerTick ) {
+ tsc /= giTime_TSCPerTick;
+ }
+ else
+ tsc = 0;
+ return giTimestamp + tsc;
+}
+
+/**
+ * \fn int Time_Setup(void)
+ * \brief Sets the system time from the Realtime-Clock
+ */
+int Time_Setup(void)
+{
+ Uint8 val;
+
+ Log_Log("Timer", "RTC Timer firing at %iHz (%i divisor), %i.0x%08x",
+ TIMER_FREQ, TIMER_RATE, MS_PER_TICK_WHOLE, MS_PER_TICK_FRACT);
+
+ outb(0x70, inb(0x70)&0x7F); // Disable NMIs
+ __asm__ __volatile__ ("cli"); // Disable normal interrupts
+
+ // Set IRQ8 firing rate
+ outb(0x70, 0x0A); // Set the index to register A
+ val = inb(0x71); // Get the current value of register A
+ outb(0x70, 0x0A); // Reset index to A
+ val &= 0xF0;
+ val |= TIMER_RATE;
+ outb(0x71, val); // Update the timer rate
+
+ // Enable IRQ8
+ outb(0x70, 0x0B); // Set the index to register B
+ val = inb(0x71); // Read the current value of register B
+ outb(0x70, 0x0B); // Set the index again (a read will reset the index to register D)
+ outb(0x71, val | 0x40); // Write the previous value or'd with 0x40. This turns on bit 6 of register D
+
+ __asm__ __volatile__ ("sti"); // Re-enable normal interrupts
+ outb(0x70, inb(0x70)|0x80); // Re-enable NMIs
+
+ // Install IRQ Handler
+ IRQ_AddHandler(8, Time_Interrupt);
+
+ // Make sure the RTC actually fires
+ outb(0x70, 0x0C); // Select register C
+ inb(0x71); // Just throw away contents.
+
+ return 0;
+}
+
+/**
+ * \brief Called on the timekeeping IRQ
+ * \param irq IRQ number (unused)
+ */
+void Time_Interrupt(int irq)
+{
+ //Log("RTC Tick");
+ Uint64 curTSC = Time_ReadTSC();
+
+ if( giTime_TSCAtLastTick )
+ {
+ giTime_TSCPerTick = curTSC - giTime_TSCAtLastTick;
+ }
+ giTime_TSCAtLastTick = curTSC;
+
+ giTicks ++;
+ giTimestamp += MS_PER_TICK_WHOLE;
+ giPartMiliseconds += MS_PER_TICK_FRACT;
+ if(giPartMiliseconds > 0x80000000) {
+ giTimestamp ++;
+ giPartMiliseconds -= 0x80000000;
+ }
+
+ Timer_CallTimers();
+
+ // Make sure the RTC Fires again
+ outb(0x70, 0x0C); // Select register C
+ inb(0x71); // Just throw away contents.
+}
+
+#if 0
+/**
+ * \fn void Time_TimerThread(void)
+ */
+void Time_TimerThread(void)
+{
+ Sint64 next;
+ Threads_SetName("TIMER");
+
+ next = giTimestamp + TIMER_QUANTUM;
+ for(;;)
+ {
+ while(giTimestamp < next) Threads_Yield();
+ next = giTimestamp + TIMER_QUANTUM;
+ Timer_CallTimers();
+ }
+}
+#endif
+
+Uint64 Time_ReadTSC(void)
+{
+ Uint32 a, d;
+ __asm__ __volatile__ ("rdtsc" : "=a" (a), "=d" (d));
+ return ((Uint64)d << 32) | a;
+}
git.ucc.asn.au / tpg / acess2.git / commitdiff
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