libsys: refactor frclock api

Make the frclock functions similar to the tsc utility functions. This
way, we can call frclock functions from the framebuffer driver which
will use frclock on ARM and tsc on X86.

Also, frclock_64_to_micros computed seconds, not microseconds

Change-Id: I6718ae0fb7db050794f6f032205923e1a32dc1ac

include/minix/sysutil.h

@@ -62,11 +62,12 @@ u32_t tsc_to_micros(u32_t low, u32_t high);
 u32_t tsc_get_khz(void);
 u32_t micros_to_ticks(u32_t micros);
 #if defined(__arm__)
-u32_t read_frclock(void);
+void read_frclock(u32_t *frclk);
 u32_t delta_frclock(u32_t base, u32_t cur);
-u64_t read_frclock_64(void);
-u64_t delta_frclock_64(u64_t base, u64_t cur);
 #endif
+void read_frclock_64(u64_t *frclk);
+u64_t delta_frclock_64(u64_t base, u64_t cur);
+u32_t frclock_64_to_micros(u64_t tsc);
 void ser_putc(char c);
 void get_randomness(struct k_randomness *, int);
 u32_t sqrt_approx(u32_t);

lib/libsys/arch/earm/frclock_util.c

@@ -9,7 +9,7 @@
 #include <minix/type.h>
 #include <sys/errno.h>
 #include <sys/types.h>
-
+#include <assert.h>
 
 static u64_t calib_hz = 1625000, Hz;
 #define MICROHZ         1000000ULL	/* number of micros per second */
@@ -23,7 +23,7 @@ micro_delay(u32_t micros)
 	Hz = sys_hz();
 
         /* Start of delay. */
-        start = read_frclock_64();
+        read_frclock_64(&start);
 	delta_end = (calib_hz * micros) / MICROHZ;
 
         /* If we have to wait for at least one HZ tick, use the regular
@@ -37,7 +37,7 @@ micro_delay(u32_t micros)
 
         /* Wait (the rest) of the delay time using busywait. */
 	do {
-                delta = read_frclock_64();
+                read_frclock_64(&delta);
 	} while (delta_frclock_64(start, delta) < delta_end);
 
 
@@ -46,16 +46,18 @@ micro_delay(u32_t micros)
 
 u32_t frclock_64_to_micros(u64_t tsc)
 {
-        return (u32_t) tsc / calib_hz;
+        return (u32_t) tsc / (calib_hz / MICROHZ);
 }
 
-u32_t
-read_frclock(void)
+void
+read_frclock(u32_t *frclk)
 {
 	extern struct minix_kerninfo *_minix_kerninfo;
 	volatile u32_t *frclock;
+
+	assert(frclk);
 	frclock = (u32_t *)((u8_t *) _minix_kerninfo->minix_frclock+OMAP3_TCRR);
-	return (u64_t) *frclock;
+	*frclk = *frclock;
 }
 
 u32_t
@@ -75,15 +77,15 @@ delta_frclock(u32_t base, u32_t cur)
 	return delta;
 }
 
-u64_t
-read_frclock_64(void)
+void
+read_frclock_64(u64_t *frclk)
 {
-	return (u64_t) read_frclock();
+	read_frclock((u32_t *) frclk);	
 }
 
 u64_t
 delta_frclock_64(u64_t base, u64_t cur)
 {
-	return delta_frclock((u32_t) base, (u32_t) cur);
+	return (u64_t) delta_frclock((u32_t) base, (u32_t) cur);
 }
 

lib/libsys/arch/earm/spin.c

@@ -55,11 +55,11 @@ int spin_check(spin_t *s)
 
 	case STATE_BASE_TS:
 		s->s_state = STATE_TS;
-		s->s_base_tsc = read_frclock_64();
+		read_frclock_64(&s->s_base_tsc);
 		break;
 
 	case STATE_TS:
-		cur_tsc = read_frclock_64();
+		read_frclock_64(&cur_tsc);
 		tsc_delta = delta_frclock_64(s->s_base_tsc, cur_tsc);
 		micro_delta = frclock_64_to_micros(tsc_delta);
 

lib/libsys/arch/i386/frclock_util.c

@@ -0,0 +1,89 @@
+/* Some utility functions around the free running clock on ARM. The clock is
+ * 32-bits wide, but we provide 64-bit wrapper functions to make it look
+ * similar to the read_tsc functions. On hardware we could actually make use
+ * of the timer overflow counter, but emulator doesn't emulate it. */
+
+#include "omap_timer_registers.h"
+#include <minix/minlib.h>
+#include <minix/sysutil.h>
+#include <minix/type.h>
+#include <sys/errno.h>
+#include <sys/types.h>
+
+
+static u64_t calib_hz = 1625000, Hz;
+#define MICROHZ         1000000ULL	/* number of micros per second */
+#define MICROSPERTICK(h)	(MICROHZ/(h)) /* number of micros per HZ tick */
+
+int
+micro_delay(u32_t micros)
+{
+        u64_t start, delta, delta_end;
+
+	Hz = sys_hz();
+
+        /* Start of delay. */
+        start = read_frclock_64();
+	delta_end = (calib_hz * micros) / MICROHZ;
+
+        /* If we have to wait for at least one HZ tick, use the regular
+         * tickdelay first. Round downwards on purpose, so the average
+         * half-tick we wait short (depending on where in the current tick
+         * we call tickdelay). We can correct for both overhead of tickdelay
+         * itself and the short wait in the busywait later.
+         */
+        if (micros >= MICROSPERTICK(Hz))
+                tickdelay(micros*Hz/MICROHZ);
+
+        /* Wait (the rest) of the delay time using busywait. */
+	do {
+                delta = read_frclock_64();
+	} while (delta_frclock_64(start, delta) < delta_end);
+
+
+        return 0;
+}
+
+u32_t frclock_64_to_micros(u64_t tsc)
+{
+        return (u32_t) tsc / calib_hz;
+}
+
+u32_t
+read_frclock(void)
+{
+	extern struct minix_kerninfo *_minix_kerninfo;
+	volatile u32_t *frclock;
+	frclock = (u32_t *)((u8_t *) _minix_kerninfo->minix_frclock+OMAP3_TCRR);
+	return (u64_t) *frclock;
+}
+
+u32_t
+delta_frclock(u32_t base, u32_t cur)
+{
+	u32_t delta;
+
+	if (cur < base) {
+		/* We have wrapped around, so delta is base to wrapping point
+		 * plus starting point (0) to cur. This supports wrapping once
+		 * only. */
+		delta = (UINT_MAX - base) + cur;
+	} else {
+		delta = cur - base;
+	}
+
+	return delta;
+}
+
+u64_t
+read_frclock_64(void)
+{
+	return (u64_t) read_frclock();
+}
+
+u64_t
+delta_frclock_64(u64_t base, u64_t cur)
+{
+	return delta_frclock((u32_t) base, (u32_t) cur);
+}
+

lib/libsys/arch/i386/tsc_util.c

@@ -107,3 +107,12 @@ u32_t tsc_get_khz(void)
 
 	return calib_mhz * 1000;
 }
+
+#define frclock_64_to_micros tsc_64_to_micros
+#define read_frclock_64 read_tsc_64
+
+u64_t delta_frclock_64(u64_t base, u64_t cur)
+{
+        return cur - base;
+}
+