Introduce the new timer subsystem.

	Timer subsystem initialization code in core/timer.c

	Split the BIOS and RTDSC timer drivers from i386_timer.c

	Split arch/i386/firmware/pcbios/bios.c into the RTSDC
	timer driver and arch/i386/core/nap.c

	Split the headers properly:
		include/unistd.h - delay functions to be used by the
					gPXE core and drivers.

		include/gpxe/timer.h - the fimer subsystem interface
					to be used by the timer drivers
					and currticks() to be used by
					the code gPXE subsystems.

		include/latch.h	- removed
		include/timer.h - scheduled for removal. Some driver
					are using currticks, which is
					only for core subsystems.

Signed-off-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>

1 files changed, 53 insertions, 160 deletions

diff --git a/src/arch/i386/core/i386_timer.c b/src/arch/i386/core/i386_timer.c
index 8d3a629ad..8f90ae05a 100644
--- a/src/arch/i386/core/i386_timer.c
+++ b/src/arch/i386/core/i386_timer.c
@@ -1,18 +1,58 @@
-/* A couple of routines to implement a low-overhead timer for drivers */
-
- /*
+/*
+ * arch/i386/core/i386_timer.c
+ *
+ * Use the "System Timer 2" to implement the udelay callback in
+ * the BIOS timer driver. Also used to calibrate the clock rate
+ * in the RTDSC timer driver.
+ * 
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2, or (at
  * your option) any later version.
  */
 
-#include	"timer.h"
-#include	"latch.h"
-#include	<io.h>
-#include	<gpxe/init.h>
+#include <stddef.h>
+#include <bits/timer2.h>
+#include <gpxe/timer.h>
+#include <io.h>
+
+/* Timers tick over at this rate */
+#define TIMER2_TICK_RATE	1193180U
+
+/* Parallel Peripheral Controller Port B */
+#define	PPC_PORTB	0x61
+
+/* Meaning of the port bits */
+#define	PPCB_T2OUT	0x20	/* Bit 5 */
+#define	PPCB_SPKR	0x02	/* Bit 1 */
+#define	PPCB_T2GATE	0x01	/* Bit 0 */
+
+/* Ports for the 8254 timer chip */
+#define	TIMER2_PORT	0x42
+#define	TIMER_MODE_PORT	0x43
+
+/* Meaning of the mode bits */
+#define	TIMER0_SEL	0x00
+#define	TIMER1_SEL	0x40
+#define	TIMER2_SEL	0x80
+#define	READBACK_SEL	0xC0
+
+#define	LATCH_COUNT	0x00
+#define	LOBYTE_ACCESS	0x10
+#define	HIBYTE_ACCESS	0x20
+#define	WORD_ACCESS	0x30
+
+#define	MODE0		0x00
+#define	MODE1		0x02
+#define	MODE2		0x04
+#define	MODE3		0x06
+#define	MODE4		0x08
+#define	MODE5		0x0A
 
-void __load_timer2(unsigned int ticks)
+#define	BINARY_COUNT	0x00
+#define	BCD_COUNT	0x01
+
+static void load_timer2(unsigned int ticks)
 {
 	/*
 	 * Now let's take care of PPC channel 2
@@ -35,162 +75,15 @@ void __load_timer2(unsigned int ticks)
 	outb(ticks >> 8, TIMER2_PORT);
 }
 
-static int __timer2_running(void)
+static int timer2_running(void)
 {
 	return ((inb(PPC_PORTB) & PPCB_T2OUT) == 0);
 }
 
-#if !defined(CONFIG_TSC_CURRTICKS)
-static void setup_timers(void)
-{
-	return;
-}
-
-void load_timer2(unsigned int ticks)
-{
-	return __load_timer2(ticks);
-}
-
-int timer2_running(void)
-{
-	return __timer2_running();
-}
-
-void ndelay(unsigned int nsecs)
-{
-	waiton_timer2((nsecs * CLOCK_TICK_RATE)/1000000000);
-}
-void udelay(unsigned int usecs)
-{
-	waiton_timer2((usecs * TICKS_PER_MS)/1000);
-}
-#endif /* !defined(CONFIG_TSC_CURRTICKS) */
-
-#if defined(CONFIG_TSC_CURRTICKS)
-
-#define rdtsc(low,high) \
-     __asm__ __volatile__("rdtsc" : "=a" (low), "=d" (high))
-
-#define rdtscll(val) \
-     __asm__ __volatile__ ("rdtsc" : "=A" (val))
-
-
-/* Number of clock ticks to time with the rtc */
-#define LATCH 0xFF
-
-#define LATCHES_PER_SEC ((CLOCK_TICK_RATE + (LATCH/2))/LATCH)
-#define TICKS_PER_LATCH ((LATCHES_PER_SEC + (TICKS_PER_SEC/2))/TICKS_PER_SEC)
-
-static void sleep_latch(void)
+void i386_timer2_udelay(unsigned int usecs)
 {
-	__load_timer2(LATCH);
-	while(__timer2_running());
+		load_timer2((usecs * TIMER2_TICK_RATE)/USECS_IN_SEC);
+		while (timer2_running())
+			;
 }
 
-/* ------ Calibrate the TSC ------- 
- * Time how long it takes to excute a loop that runs in known time.
- * And find the convertion needed to get to CLOCK_TICK_RATE
- */
-
-
-static unsigned long long calibrate_tsc(void)
-{
-	unsigned long startlow, starthigh;
-	unsigned long endlow, endhigh;
-	
-	rdtsc(startlow,starthigh);
-	sleep_latch();
-	rdtsc(endlow,endhigh);
-
-	/* 64-bit subtract - gcc just messes up with long longs */
-	__asm__("subl %2,%0\n\t"
-		"sbbl %3,%1"
-		:"=a" (endlow), "=d" (endhigh)
-		:"g" (startlow), "g" (starthigh),
-		"0" (endlow), "1" (endhigh));
-	
-	/* Error: ECPUTOOFAST */
-	if (endhigh)
-		goto bad_ctc;
-	
-	endlow *= TICKS_PER_LATCH;
-	return endlow;
-
-	/*
-	 * The CTC wasn't reliable: we got a hit on the very first read,
-	 * or the CPU was so fast/slow that the quotient wouldn't fit in
-	 * 32 bits..
-	 */
-bad_ctc:
-	printf("bad_ctc\n");
-	return 0;
-}
-
-static unsigned long clocks_per_tick;
-static void setup_timers(void)
-{
-	if (!clocks_per_tick) {
-		clocks_per_tick = calibrate_tsc();
-		/* Display the CPU Mhz to easily test if the calibration was bad */
-		printf("CPU %ld Mhz\n", (clocks_per_tick/1000 * TICKS_PER_SEC)/1000);
-	}
-}
-
-unsigned long currticks(void)
-{
-	unsigned long clocks_high, clocks_low;
-	unsigned long currticks;
-	/* Read the Time Stamp Counter */
-	rdtsc(clocks_low, clocks_high);
-
-	/* currticks = clocks / clocks_per_tick; */
-	__asm__("divl %1"
-		:"=a" (currticks)
-		:"r" (clocks_per_tick), "0" (clocks_low), "d" (clocks_high));
-
-
-	return currticks;
-}
-
-static unsigned long long timer_timeout;
-static int __timer_running(void)
-{
-	unsigned long long now;
-	rdtscll(now);
-	return now < timer_timeout;
-}
-
-void udelay(unsigned int usecs)
-{
-	unsigned long long now;
-	rdtscll(now);
-	timer_timeout = now + usecs * ((clocks_per_tick * TICKS_PER_SEC)/(1000*1000));
-	while(__timer_running());
-}
-void ndelay(unsigned int nsecs)
-{
-	unsigned long long now;
-	rdtscll(now);
-	timer_timeout = now + nsecs * ((clocks_per_tick * TICKS_PER_SEC)/(1000*1000*1000));
-	while(__timer_running());
-}
-
-void load_timer2(unsigned int timer2_ticks)
-{
-	unsigned long long now;
-	unsigned long clocks;
-	rdtscll(now);
-	clocks = timer2_ticks * ((clocks_per_tick * TICKS_PER_SEC)/CLOCK_TICK_RATE);
-	timer_timeout = now + clocks;
-}
-
-int timer2_running(void)
-{
-	return __timer_running();
-}
-
-#endif /* RTC_CURRTICKS */
-
-struct init_fn timer_init_fn __init_fn ( INIT_NORMAL ) = {
-	.initialise = setup_timers,
-};