* GeekOS timer interrupt support
* Copyright (c) 2001,2003 David H. Hovemeyer <daveho@cs.umd.edu>
* Copyright (c) 2003, Jeffrey K. Hollingsworth <hollings@cs.umd.edu>
- * $Revision: 1.3 $
+ * $Revision: 1.4 $
*
* This is free software. You are permitted to use,
* redistribute, and modify it as specified in the file "COPYING".
#include <geekos/serial.h>
#include <geekos/debug.h>
-#define HZ 100
+
+/* JRL Add a cpu frequency measurement */
+uint_t cpu_khz_freq;
+
+
+#define __SLOW_DOWN_IO "\noutb %%al,$0x80"
+
+#ifdef REALLY_SLOW_IO
+#define __FULL_SLOW_DOWN_IO __SLOW_DOWN_IO __SLOW_DOWN_IO __SLOW_DOWN_IO __SLOW_DOWN_IO
+#else
+#define __FULL_SLOW_DOWN_IO __SLOW_DOWN_IO
+#endif
+
+
+
+#define __OUT1(s,x) \
+static inline void out##s(unsigned x value, unsigned short port) {
+
+#define __OUT2(s,s1,s2) \
+__asm__ __volatile__ ("out" #s " %" s1 "0,%" s2 "1"
+
+#define __OUT(s,s1,x) \
+__OUT1(s,x) __OUT2(s,s1,"w") : : "a" (value), "Nd" (port)); } \
+__OUT1(s##_p,x) __OUT2(s,s1,"w") __FULL_SLOW_DOWN_IO : : "a" (value), "Nd" (port));} \
+
+
+#define __IN1(s) \
+static inline RETURN_TYPE in##s(unsigned short port) { RETURN_TYPE _v;
+
+#define __IN2(s,s1,s2) \
+__asm__ __volatile__ ("in" #s " %" s2 "1,%" s1 "0"
+
+#define __IN(s,s1,i...) \
+__IN1(s) __IN2(s,s1,"w") : "=a" (_v) : "Nd" (port) ,##i ); return _v; } \
+__IN1(s##_p) __IN2(s,s1,"w") __FULL_SLOW_DOWN_IO : "=a" (_v) : "Nd" (port) ,##i ); return _v; } \
+
+
+#define RETURN_TYPE unsigned char
+__IN(b,"")
+#undef RETURN_TYPE
+#define RETURN_TYPE unsigned short
+__IN(w,"")
+#undef RETURN_TYPE
+#define RETURN_TYPE unsigned int
+__IN(l,"")
+#undef RETURN_TYPE
+
+
+
+__OUT(b,"b",char)
+__OUT(w,"w",short)
+
+
+
+
+
+#if defined(__i386__)
+
+#define rdtscll(val) \
+ __asm__ __volatile__("rdtsc" : "=A" (val))
+
+#elif defined(__x86_64__)
+
+#define rdtscll(val) do { \
+ unsigned int a,d; \
+ asm volatile("rdtsc" : "=a" (a), "=d" (d)); \
+ (val) = ((unsigned long)a) | (((unsigned long)d)<<32); \
+ } while(0)
+
+#endif
+
+#define do_div(n,base) ({ \
+ unsigned long __upper, __low, __high, __mod, __base; \
+ __base = (base); \
+ asm("":"=a" (__low), "=d" (__high):"A" (n)); \
+ __upper = __high; \
+ if (__high) { \
+ __upper = __high % (__base); \
+ __high = __high / (__base); \
+ } \
+ asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (__base), "0" (__low), "1" (__upper)); \
+ asm("":"=A" (n):"a" (__low),"d" (__high)); \
+ __mod; \
+ })
+
+
+/**
+ * This uses the Programmable Interval Timer that is standard on all
+ * PC-compatible systems to determine the time stamp counter frequency.
+ *
+ * This uses the speaker output (channel 2) of the PIT. This is better than
+ * using the timer interrupt output because we can read the value of the
+ * speaker with just one inb(), where we need three i/o operations for the
+ * interrupt channel. We count how many ticks the TSC does in 50 ms.
+ *
+ * Returns the detected time stamp counter frequency in KHz.
+ */
+
+
+static unsigned int
+pit_calibrate_tsc(void)
+{
+ uint_t khz = 0;
+ ullong_t start, end;
+ // unsigned long flags;
+ unsigned long pit_tick_rate = 1193182UL; /* 1.193182 MHz */
+
+ // spin_lock_irqsave(&pit_lock, flags);
+
+ outb((inb(0x61) & ~0x02) | 0x01, 0x61);
+
+ outb(0xb0, 0x43);
+ outb((pit_tick_rate / (1000 / 50)) & 0xff, 0x42);
+ outb((pit_tick_rate / (1000 / 50)) >> 8, 0x42);
+ // start = get_cycles_sync();
+ rdtscll(start);
+ while ((inb(0x61) & 0x20) == 0);
+ rdtscll(end);
+ // end = get_cycles_sync();
+
+ // spin_unlock_irqrestore(&pit_lock, flags);
+
+
+ // return (end - start) / 50;
+ khz = end - start;
+;
+
+ return khz / 50;
+}
+
+
+
+/* END JRL */
+
+
+
/*
* Ticks per second.
* FIXME: should set this to something more reasonable, like 100.
*/
-#define TICKS_PER_SEC 18
+#define HZ 100
+//#define TICKS_PER_SEC 18
/*#define DEBUG_TIMER */
#ifdef DEBUG_TIMER
;
/*
- * Execute the spin loop.
+ * Execute the spin loop.xs
* The temporary interrupt handler will overwrite the
* loop counter when the next tick occurs.
*/
+
+
Spin(INT_MAX);
+
+
Disable_Interrupts();
/*
{
ushort_t foo = 1193182L / HZ;
+ cpu_khz_freq = pit_calibrate_tsc();
+ PrintBoth("CPU KHZ=%lu\n", (ulong_t)cpu_khz_freq);
+
PrintBoth("Initializing timer and setting to %d Hz...\n",HZ);
/* Calibrate for delay loop */
}
-#define US_PER_TICK (TICKS_PER_SEC * 1000000)
+#define US_PER_TICK (HZ * 1000000)
/*
* Spin for at least given number of microseconds.
