Merge branch 'xl0-timer'

70 files changed, 412 insertions, 398 deletions

diff --git a/src/arch/i386/Makefile b/src/arch/i386/Makefile
index 5e7416cb..da7976df 100644
--- a/src/arch/i386/Makefile
+++ b/src/arch/i386/Makefile
@@ -7,6 +7,7 @@ ISOLINUX_BIN	= /usr/lib/syslinux/isolinux.bin
 SRCDIRS		+= arch/i386/core arch/i386/transitions arch/i386/prefix
 SRCDIRS		+= arch/i386/firmware/pcbios
 SRCDIRS		+= arch/i386/image
+SRCDIRS		+= arch/i386/drivers
 SRCDIRS		+= arch/i386/drivers/bus
 SRCDIRS		+= arch/i386/drivers/net
 SRCDIRS		+= arch/i386/drivers/disk
diff --git a/src/arch/i386/core/i386_timer.c b/src/arch/i386/core/i386_timer.c
index 8d3a629a..8f90ae05 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,
-};
diff --git a/src/arch/i386/core/nap.c b/src/arch/i386/core/nap.c
new file mode 100644
index 00000000..12bb5699
--- /dev/null
+++ b/src/arch/i386/core/nap.c
@@ -0,0 +1,12 @@
+
+#include <realmode.h>
+#include <bios.h>
+
+/**************************************************************************
+ * Save power by halting the CPU until the next interrupt
+ **************************************************************************/
+void cpu_nap ( void ) {
+	__asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
+					   "hlt\n\t"
+					   "cli\n\t" ) : : );
+}
diff --git a/src/arch/i386/drivers/timer_bios.c b/src/arch/i386/drivers/timer_bios.c
new file mode 100644
index 00000000..f9caf8d9
--- /dev/null
+++ b/src/arch/i386/drivers/timer_bios.c
@@ -0,0 +1,57 @@
+/*
+ * Etherboot routines for PCBIOS firmware.
+ *
+ * Body of routines taken from old pcbios.S
+ */
+
+#include <gpxe/init.h>
+#include <gpxe/timer.h>
+#include <stdio.h>
+#include <realmode.h>
+#include <bios.h>
+#include <bits/timer2.h>
+
+/* A bit faster actually, but we don't care. */
+#define	TIMER2_TICKS_PER_SEC	18
+
+/*
+ * Use direct memory access to BIOS variables, longword 0040:006C (ticks
+ * today) and byte 0040:0070 (midnight crossover flag) instead of calling
+ * timeofday BIOS interrupt.
+ */
+
+static tick_t bios_currticks ( void ) {
+	static int days = 0;
+	uint32_t ticks;
+	uint8_t midnight;
+
+	/* Re-enable interrupts so that the timer interrupt can occur */
+	__asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
+					   "nop\n\t"
+					   "nop\n\t"
+					   "cli\n\t" ) : : );
+
+	get_real ( ticks, BDA_SEG, 0x006c );
+	get_real ( midnight, BDA_SEG, 0x0070 );
+
+	if ( midnight ) {
+		midnight = 0;
+		put_real ( midnight, BDA_SEG, 0x0070 );
+		days += 0x1800b0;
+	}
+
+	return ( (days + ticks) * (USECS_IN_SEC / TIMER2_TICKS_PER_SEC) );
+}
+
+static int bios_ts_init(void)
+{
+	DBG("BIOS timer installed\n");
+	return 0;
+}
+
+struct timer bios_ts __timer ( 02 ) = {
+	.init = bios_ts_init,
+	.udelay = i386_timer2_udelay,
+	.currticks = bios_currticks,
+};
+
diff --git a/src/arch/i386/drivers/timer_rdtsc.c b/src/arch/i386/drivers/timer_rdtsc.c
new file mode 100644
index 00000000..09b7df2f
--- /dev/null
+++ b/src/arch/i386/drivers/timer_rdtsc.c
@@ -0,0 +1,69 @@
+
+#include <gpxe/init.h>
+#include <gpxe/timer.h>
+#include <errno.h>
+#include <stdio.h>
+#include <bits/cpu.h>
+#include <bits/timer2.h>
+#include <io.h>
+
+
+#define rdtsc(low,high) \
+     __asm__ __volatile__("rdtsc" : "=a" (low), "=d" (high))
+
+#define rdtscll(val) \
+     __asm__ __volatile__ ("rdtsc" : "=A" (val))
+
+
+/* Measure how many clocks we get in one microsecond */
+static inline uint64_t calibrate_tsc(void)
+{
+
+	uint64_t rdtsc_start;
+	uint64_t rdtsc_end;
+
+	rdtscll(rdtsc_start);
+	i386_timer2_udelay(USECS_IN_MSEC);
+	rdtscll(rdtsc_end);
+	
+	return (rdtsc_end - rdtsc_start) / USECS_IN_MSEC;
+}
+
+static uint32_t clocks_per_usec = 0;
+
+/* We measure time in microseconds. */
+static tick_t rdtsc_currticks(void)
+{
+	uint64_t clocks;
+
+	/* Read the Time Stamp Counter */
+	rdtscll(clocks);
+
+	return clocks / clocks_per_usec;
+}
+
+static int rdtsc_ts_init(void)
+{
+
+	struct cpuinfo_x86 cpu_info;
+
+	get_cpuinfo(&cpu_info);
+	if (cpu_info.features & X86_FEATURE_TSC) {
+		clocks_per_usec= calibrate_tsc();
+		if (clocks_per_usec) {
+			DBG("RDTSC ticksource installed. CPU running at %ld Mhz\n",
+				clocks_per_usec);
+			return 0;
+		}
+	}
+
+	DBG("RDTSC ticksource not available on this machine.\n");
+	return -ENODEV;
+}
+
+struct timer rdtsc_ts __timer (01) = {
+	.init = rdtsc_ts_init,
+	.udelay = generic_currticks_udelay,
+	.currticks = rdtsc_currticks,
+};
+
diff --git a/src/arch/i386/firmware/pcbios/bios.c b/src/arch/i386/firmware/pcbios/bios.c
deleted file mode 100644
index bcbe98a8..00000000
--- a/src/arch/i386/firmware/pcbios/bios.c
+++ /dev/null
@@ -1,55 +0,0 @@
-/* Etherboot routines for PCBIOS firmware.
- *
- * Body of routines taken from old pcbios.S
- */
-
-#include <stdint.h>
-#include <realmode.h>
-#include <bios.h>
-
-#define CF ( 1 << 0 )
-
-/**************************************************************************
-CURRTICKS - Get Time
-Use direct memory access to BIOS variables, longword 0040:006C (ticks
-today) and byte 0040:0070 (midnight crossover flag) instead of calling
-timeofday BIOS interrupt.
-**************************************************************************/
-#if defined(CONFIG_TSC_CURRTICKS)
-#undef CONFIG_BIOS_CURRTICKS
-#else
-#define CONFIG_BIOS_CURRTICKS 1
-#endif
-#if defined(CONFIG_BIOS_CURRTICKS)
-unsigned long currticks ( void ) {
-	static uint32_t days = 0;
-	uint32_t ticks;
-	uint8_t midnight;
-
-	/* Re-enable interrupts so that the timer interrupt can occur
-	 */
-	__asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
-					   "nop\n\t"
-					   "nop\n\t"
-					   "cli\n\t" ) : : );
-
-	get_real ( ticks, BDA_SEG, 0x006c );
-	get_real ( midnight, BDA_SEG, 0x0070 );
-
-	if ( midnight ) {
-		midnight = 0;
-		put_real ( midnight, BDA_SEG, 0x0070 );
-		days += 0x1800b0;
-	}
-	return ( days + ticks );
-}
-#endif	/* CONFIG_BIOS_CURRTICKS */
-
-/**************************************************************************
-CPU_NAP - Save power by halting the CPU until the next interrupt
-**************************************************************************/
-void cpu_nap ( void ) {
-	__asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
-					   "hlt\n\t"
-					   "cli\n\t" ) : : );
-}
diff --git a/src/arch/i386/firmware/pcbios/gateA20.c b/src/arch/i386/firmware/pcbios/gateA20.c
index 66b4da18..2caac894 100644
--- a/src/arch/i386/firmware/pcbios/gateA20.c
+++ b/src/arch/i386/firmware/pcbios/gateA20.c
@@ -1,8 +1,7 @@
 #include <stdio.h>
-#include "realmode.h"
-#include "timer.h"
-#include "latch.h"
-#include "bios.h"
+#include <realmode.h>
+#include <bios.h>
+#include <gpxe/timer.h>
 
 #define K_RDWR		0x60		/* keyboard data & cmds (read/write) */
 #define K_STATUS	0x64		/* keyboard status */
diff --git a/src/arch/i386/include/bits/errfile.h b/src/arch/i386/include/bits/errfile.h
index a6f87825..0f140214 100644
--- a/src/arch/i386/include/bits/errfile.h
+++ b/src/arch/i386/include/bits/errfile.h
@@ -26,6 +26,9 @@
 #define ERRFILE_undionly	 ( ERRFILE_ARCH | ERRFILE_NET | 0x00030000 )
 #define ERRFILE_undirom		 ( ERRFILE_ARCH | ERRFILE_NET | 0x00040000 )
 
+#define ERRFILE_timer_rdtsc    ( ERRFILE_ARCH | ERRFILE_DRIVER | 0x00000000 )
+#define ERRFILE_timer_bios     ( ERRFILE_ARCH | ERRFILE_DRIVER | 0x00010000 )
+
 /** @} */
 
 #endif /* _BITS_ERRFILE_H */
diff --git a/src/arch/i386/include/bits/timer2.h b/src/arch/i386/include/bits/timer2.h
new file mode 100644
index 00000000..83923b29
--- /dev/null
+++ b/src/arch/i386/include/bits/timer2.h
@@ -0,0 +1,8 @@
+#ifndef BITS_TIMER2_H
+#define BITS_TIMER2_H
+
+#include <stddef.h>
+
+void i386_timer2_udelay(unsigned int usecs);
+
+#endif
diff --git a/src/arch/i386/include/latch.h b/src/arch/i386/include/latch.h
deleted file mode 100644
index 5000d582..00000000
--- a/src/arch/i386/include/latch.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef LATCH_H
-#define LATCH_H
-
-#define	TICKS_PER_SEC		18
-
-/* For different calibrators of the TSC move the declaration of
- * sleep_latch and the definitions of it's length here...
- */
-
-extern unsigned long currticks ( void );
-
-#endif /* LATCH_H */
diff --git a/src/config.h b/src/config.h
index e5d8b114..e004f23d 100644
--- a/src/config.h
+++ b/src/config.h
@@ -51,6 +51,16 @@
 
 /* @END serial.h */
 
+/* @BEGIN general.h
+ *
+ * Timer configuration
+ *
+ */
+#define TIMER_BIOS		/* 18Hz BIOS timer */
+#define TIMER_RDTSC		/* CPU TimeStamp Counter timer */
+
+/* @END general.h */
+
 /* @BEGIN isa.h
  *
  * ISA probe address configuration
diff --git a/src/core/config.c b/src/core/config.c
index e7db221a..24db3557 100644
--- a/src/core/config.c
+++ b/src/core/config.c
@@ -75,6 +75,17 @@ REQUIRE_OBJECT ( syslog );
 #endif
 
 /*
+ * Timers
+ */
+
+#ifdef TIMER_BIOS
+REQUIRE_OBJECT ( timer_bios );
+#endif
+
+#ifdef TIMER_RDTSC
+REQUIRE_OBJECT ( timer_rdtsc );
+#endif
+/*
  * Drag in all requested protocols
  *
  */
diff --git a/src/core/getkey.c b/src/core/getkey.c
index 71ec6cc1..1551cf37 100644
--- a/src/core/getkey.c
+++ b/src/core/getkey.c
@@ -17,9 +17,9 @@
  */
 
 #include <console.h>
-#include <latch.h>
 #include <gpxe/process.h>
 #include <gpxe/keys.h>
+#include <gpxe/timer.h>
 
 /** @file
  *
diff --git a/src/core/misc.c b/src/core/misc.c
index 4219a36c..a54f5a10 100644
--- a/src/core/misc.c
+++ b/src/core/misc.c
@@ -4,20 +4,8 @@ MISC Support Routines
 
 #include <stdlib.h>
 #include <byteswap.h>
-#include <latch.h>
 #include <gpxe/in.h>
-
-/**************************************************************************
-SLEEP
-**************************************************************************/
-unsigned int sleep(unsigned int secs)
-{
-	unsigned long tmo;
-
-	for (tmo = currticks()+secs*TICKS_PER_SEC; currticks() < tmo; ) {
-	}
-	return 0;
-}
+#include <gpxe/timer.h>
 
 /**************************************************************************
 INET_ATON - Convert an ascii x.x.x.x to binary form
diff --git a/src/core/random.c b/src/core/random.c
index e4a70d43..d34e763a 100644
--- a/src/core/random.c
+++ b/src/core/random.c
@@ -5,7 +5,7 @@
  */
 
 #include <stdlib.h>
-#include <latch.h>
+#include <gpxe/timer.h>
 
 static int32_t rnd_seed = 0;
 
diff --git a/src/core/serial.c b/src/core/serial.c
index f325bc45..f6d0ecbb 100644
--- a/src/core/serial.c
+++ b/src/core/serial.c
@@ -15,7 +15,7 @@
 #include "console.h"
 #include <gpxe/init.h>
 #include "io.h"
-#include "timer.h"
+#include <unistd.h>
 #include "config/serial.h"
 
 /* Set default values if none specified */
diff --git a/src/core/timer.c b/src/core/timer.c
index c56e5310..e736f528 100644
--- a/src/core/timer.c
+++ b/src/core/timer.c
@@ -1,27 +1,100 @@
-/* A couple of routines to implement a low-overhead timer for drivers */
-
- /*
+/*
+ * core/timer.c
+ *
+ * Copyright (C) 2007 Alexey Zaytsev <alexey.zaytsev@gmail.com>
+ *
  * 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.
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include	"timer.h"
+#include <stddef.h>
+#include <assert.h>
+#include <gpxe/init.h>
+#include <gpxe/timer.h>
+#include <stdio.h>
 
-/* Machine Independant timer helper functions */
+static struct timer ts_table[0]
+	__table_start ( struct timer, timers );
+static struct timer ts_table_end[0]
+	__table_end ( struct timer, timers );
 
-void mdelay(unsigned int msecs)
+
+static struct timer *used_ts = NULL;
+
+/*
+ * This function may be used in custom timer driver.
+ *
+ * This udelay implementation works well if you've got a
+ * fast currticks().
+ */
+void generic_currticks_udelay(unsigned int usecs)
 {
-	unsigned int i;
-	for(i = 0; i < msecs; i++) {
-		udelay(1000);
-	}
+	tick_t t;
+
+	t = currticks();
+	while (t + usecs > currticks())
+		; /* xxx: Relax the cpu some way. */
 }
 
-void waiton_timer2(unsigned int ticks)
+
+static void timer_init(void)
 {
-	load_timer2(ticks);
-	while(timer2_running()) {
+	struct timer *ts;
+
+	for (ts = ts_table; ts < ts_table_end; ts++) {
+		if (ts->init && ts->init() >= 0) {
+			used_ts = ts;
+			break;
+		}
 	}
+
+	assert(used_ts);
 }
+
+struct init_fn ts_init_fn __init_fn ( INIT_NORMAL ) = {
+	.initialise = timer_init,
+};
+
+/* Functions for public use. */
+
+tick_t currticks(void)
+{
+	tick_t ct;
+	assert(used_ts);
+
+	ct = used_ts->currticks();
+	DBG("currticks: %ld seconds and %06ld microseconds\n", ct/USECS_IN_SEC, ct%USECS_IN_SEC);
+
+	return ct;
+}
+
+void udelay(unsigned int usecs)
+{
+	used_ts->udelay(usecs);
+}
+
+void mdelay(unsigned int msecs)
+{
+	while(msecs--)
+		used_ts->udelay(USECS_IN_MSEC);
+}
+
+unsigned int sleep(unsigned int secs)
+{
+	while (secs--)
+		mdelay(MSECS_IN_SEC);
+
+	return 0;
+}
+
diff --git a/src/drivers/bitbash/bitbash.c b/src/drivers/bitbash/bitbash.c
index ec94feee..c6f93520 100644
--- a/src/drivers/bitbash/bitbash.c
+++ b/src/drivers/bitbash/bitbash.c
@@ -16,7 +16,6 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include <timer.h>
 #include <gpxe/bitbash.h>
 
 /** @file
diff --git a/src/drivers/bitbash/i2c_bit.c b/src/drivers/bitbash/i2c_bit.c
index d8fbacc0..a3af610b 100644
--- a/src/drivers/bitbash/i2c_bit.c
+++ b/src/drivers/bitbash/i2c_bit.c
@@ -20,7 +20,7 @@
 #include <stdint.h>
 #include <errno.h>
 #include <assert.h>
-#include <timer.h>
+#include <unistd.h>
 #include <gpxe/bitbash.h>
 #include <gpxe/i2c.h>
 
diff --git a/src/drivers/bitbash/spi_bit.c b/src/drivers/bitbash/spi_bit.c
index a4e7136f..ef87b5a2 100644
--- a/src/drivers/bitbash/spi_bit.c
+++ b/src/drivers/bitbash/spi_bit.c
@@ -22,7 +22,7 @@
 #include <byteswap.h>
 #include <errno.h>
 #include <assert.h>
-#include <timer.h>
+#include <unistd.h>
 #include <gpxe/bitbash.h>
 #include <gpxe/spi_bit.h>
 
diff --git a/src/drivers/bus/eisa.c b/src/drivers/bus/eisa.c
index d9d02d72..ee03df3a 100644
--- a/src/drivers/bus/eisa.c
+++ b/src/drivers/bus/eisa.c
@@ -4,7 +4,7 @@
 #include <stdio.h>
 #include <errno.h>
 #include <io.h>
-#include <timer.h>
+#include <unistd.h>
 #include <gpxe/eisa.h>
 
 static struct eisa_driver eisa_drivers[0]
diff --git a/src/drivers/bus/isapnp.c b/src/drivers/bus/isapnp.c
index 7903208d..f4968eb1 100644
--- a/src/drivers/bus/isapnp.c
+++ b/src/drivers/bus/isapnp.c
@@ -61,7 +61,7 @@
 #include <stdio.h>
 #include <errno.h>
 #include <io.h>
-#include <timer.h>
+#include <unistd.h>
 #include <gpxe/isapnp.h>
 
 /**
diff --git a/src/drivers/bus/mca.c b/src/drivers/bus/mca.c
index 375a6834..eb7b7e39 100644
--- a/src/drivers/bus/mca.c
+++ b/src/drivers/bus/mca.c
@@ -11,7 +11,6 @@
 #include <stdio.h>
 #include <errno.h>
 #include <io.h>
-#include <timer.h>
 #include <gpxe/mca.h>
 
 static struct mca_driver mca_drivers[0]
diff --git a/src/drivers/infiniband/arbel.c b/src/drivers/infiniband/arbel.c
index 147cf8b9..462638ea 100644
--- a/src/drivers/infiniband/arbel.c
+++ b/src/drivers/infiniband/arbel.c
@@ -26,7 +26,6 @@
 #include <strings.h>
 #include <unistd.h>
 #include <errno.h>
-#include <timer.h>
 #include <byteswap.h>
 #include <gpxe/pci.h>
 #include <gpxe/malloc.h>
diff --git a/src/drivers/infiniband/hermon.c b/src/drivers/infiniband/hermon.c
index fecf3988..c10559f9 100644
--- a/src/drivers/infiniband/hermon.c
+++ b/src/drivers/infiniband/hermon.c
@@ -24,7 +24,6 @@
 #include <strings.h>
 #include <unistd.h>
 #include <errno.h>
-#include <timer.h>
 #include <byteswap.h>
 #include <gpxe/pci.h>
 #include <gpxe/malloc.h>
diff --git a/src/drivers/net/3c509.c b/src/drivers/net/3c509.c
index e704cfca..8a15aff2 100644
--- a/src/drivers/net/3c509.c
+++ b/src/drivers/net/3c509.c
@@ -9,7 +9,7 @@
 #include <string.h>
 #include <errno.h>
 #include <io.h>
-#include <timer.h>
+#include <unistd.h>
 #include <gpxe/device.h>
 #include <gpxe/isa.h>
 #include "3c509.h"
diff --git a/src/drivers/net/3c515.c b/src/drivers/net/3c515.c
index d0bf3189..02f03dc7 100644
--- a/src/drivers/net/3c515.c
+++ b/src/drivers/net/3c515.c
@@ -50,7 +50,6 @@
 #include "nic.h"
 #include <gpxe/isapnp.h>
 #include <gpxe/isa.h> /* for ISA_ROM */
-#include "timer.h"
 #include <gpxe/ethernet.h>
 
 static void t3c515_wait(unsigned int nticks)
diff --git a/src/drivers/net/3c595.c b/src/drivers/net/3c595.c
index 572a99e0..7138f936 100644
--- a/src/drivers/net/3c595.c
+++ b/src/drivers/net/3c595.c
@@ -30,7 +30,6 @@
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
 #include "3c595.h"
-#include "timer.h"
 
 static struct nic_operations t595_operations;
 
diff --git a/src/drivers/net/3c5x9.c b/src/drivers/net/3c5x9.c
index 1ade6f47..565044a1 100644
--- a/src/drivers/net/3c5x9.c
+++ b/src/drivers/net/3c5x9.c
@@ -28,7 +28,6 @@ $Id$
 #include "etherboot.h"
 #include "nic.h"
 #include <gpxe/isa.h>
-#include "timer.h"
 #include "3c509.h"
 
 static enum { none, bnc, utp } connector = none;	/* for 3C509 */
diff --git a/src/drivers/net/3c90x.c b/src/drivers/net/3c90x.c
index 8e1f160e..8158239d 100644
--- a/src/drivers/net/3c90x.c
+++ b/src/drivers/net/3c90x.c
@@ -43,7 +43,6 @@
 #include "nic.h"
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
-#include "timer.h"
 
 static struct nic_operations a3c90x_operations;
 
@@ -498,6 +497,7 @@ a3c90x_transmit(struct nic *nic __unused, const char *d, unsigned int t,
 
     unsigned char status;
     unsigned i, retries;
+    tick_t ct;
 
     for (retries=0; retries < XMIT_RETRIES ; retries++)
 	{
@@ -540,9 +540,10 @@ a3c90x_transmit(struct nic *nic __unused, const char *d, unsigned int t,
 	    ;
 
 	/** Wait for NIC Transmit to Complete **/
-	load_timer2(10*TICKS_PER_MS);	/* Give it 10 ms */
+	ct = currticks();
+
 	while (!(inw(INF_3C90X.IOAddr + regCommandIntStatus_w)&0x0004) &&
-		timer2_running())
+		ct + 10*USECS_IN_MSEC < currticks());
 		;
 
 	if (!(inw(INF_3C90X.IOAddr + regCommandIntStatus_w)&0x0004))
diff --git a/src/drivers/net/amd8111e.c b/src/drivers/net/amd8111e.c
index c26c07cf..1c41add1 100644
--- a/src/drivers/net/amd8111e.c
+++ b/src/drivers/net/amd8111e.c
@@ -33,7 +33,6 @@
 #include "mii.h"
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
-#include "timer.h"
 #include "string.h"
 #include "stdint.h"
 #include "amd8111e.h"
diff --git a/src/drivers/net/bnx2.c b/src/drivers/net/bnx2.c
index fdd6655b..9c989c4c 100644
--- a/src/drivers/net/bnx2.c
+++ b/src/drivers/net/bnx2.c
@@ -18,7 +18,6 @@
 #include <errno.h>
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
-#include "timer.h"
 #include "string.h"
 #include "bnx2.h"
 #include "bnx2_fw.h"
diff --git a/src/drivers/net/dmfe.c b/src/drivers/net/dmfe.c
index 34e211d4..9cf50418 100644
--- a/src/drivers/net/dmfe.c
+++ b/src/drivers/net/dmfe.c
@@ -43,7 +43,6 @@
 /* to get the PCI support functions, if this is a PCI NIC */
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
-#include "timer.h"
 
 /* #define EDEBUG 1 */
 #ifdef EDEBUG
diff --git a/src/drivers/net/e1000/e1000.h b/src/drivers/net/e1000/e1000.h
index b4bc1d87..4ae41451 100644
--- a/src/drivers/net/e1000/e1000.h
+++ b/src/drivers/net/e1000/e1000.h
@@ -36,7 +36,6 @@
 #include <stdio.h>
 #include <io.h>
 #include <errno.h>
-#include <timer.h>
 #include <byteswap.h>
 #include <gpxe/pci.h>
 #include <gpxe/malloc.h>
diff --git a/src/drivers/net/e1000/e1000_osdep.h b/src/drivers/net/e1000/e1000_osdep.h
index 04e14892..7df9b5e9 100644
--- a/src/drivers/net/e1000/e1000_osdep.h
+++ b/src/drivers/net/e1000/e1000_osdep.h
@@ -39,7 +39,7 @@
 #include <stdio.h>
 #include <io.h>
 #include <errno.h>
-#include <timer.h>
+#include <unistd.h>
 #include <byteswap.h>
 #include <gpxe/pci.h>
 #include <gpxe/if_ether.h>
diff --git a/src/drivers/net/eepro.c b/src/drivers/net/eepro.c
index 0a9c95e6..2a163d1b 100644
--- a/src/drivers/net/eepro.c
+++ b/src/drivers/net/eepro.c
@@ -35,7 +35,6 @@ has 34 pins, the top row of 2 are not used.
 #include <errno.h>
 #include "nic.h"
 #include <gpxe/isa.h>
-#include "timer.h"
 #include <gpxe/ethernet.h>
 
 /* Different 82595 chips */
diff --git a/src/drivers/net/eepro100.c b/src/drivers/net/eepro100.c
index bb46d163..f746976a 100644
--- a/src/drivers/net/eepro100.c
+++ b/src/drivers/net/eepro100.c
@@ -107,7 +107,6 @@
 #include "nic.h"
 #include <gpxe/ethernet.h>
 #include <gpxe/pci.h>
-#include "timer.h"
 
 static int ioaddr;
 
@@ -408,6 +407,7 @@ static void eepro100_transmit(struct nic *nic, const char *d, unsigned int t, un
 	} hdr;
 	unsigned short status;
 	int s1, s2;
+	tick_t ct;
 
 	status = inw(ioaddr + SCBStatus);
 	/* Acknowledge all of the current interrupt sources ASAP. */
@@ -445,8 +445,10 @@ static void eepro100_transmit(struct nic *nic, const char *d, unsigned int t, un
 	wait_for_cmd_done(ioaddr + SCBCmd);
 
 	s1 = inw (ioaddr + SCBStatus);
-	load_timer2(10*TICKS_PER_MS);		/* timeout 10 ms for transmit */
-	while (!txfd.status && timer2_running())
+
+	ct = currticks();
+	/* timeout 10 ms for transmit */
+	while (!txfd.status && ct + 10*USECS_IN_MSEC)
 		/* Wait */;
 	s2 = inw (ioaddr + SCBStatus);
 
@@ -606,6 +608,7 @@ static int eepro100_probe ( struct nic *nic, struct pci_device *pci ) {
 	int read_cmd, ee_size;
 	int options;
 	int rx_mode;
+	tick_t ct;
 
 	/* we cache only the first few words of the EEPROM data
 	   be careful not to access beyond this array */
@@ -749,8 +752,8 @@ static int eepro100_probe ( struct nic *nic, struct pci_device *pci ) {
 
 	whereami ("started TX thingy (config, iasetup).");
 
-	load_timer2(10*TICKS_PER_MS);
-	while (!txfd.status && timer2_running())
+	ct = currticks();
+	while (!txfd.status && ct + 10*USECS_IN_MSEC < currticks())
 		/* Wait */;
 
 	/* Read the status register once to disgard stale data */
diff --git a/src/drivers/net/epic100.c b/src/drivers/net/epic100.c
index e79da2b9..67b4f0fb 100644
--- a/src/drivers/net/epic100.c
+++ b/src/drivers/net/epic100.c
@@ -8,7 +8,6 @@
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
 #include "nic.h"
-#include "timer.h"
 #include "console.h"
 #include "epic100.h"
 
@@ -310,6 +309,7 @@ epic100_transmit(struct nic *nic, const char *destaddr, unsigned int type,
     unsigned short nstype;
     unsigned char *txp;
     int entry;
+    tick_t ct;
 
     /* Calculate the next Tx descriptor entry. */
     entry = cur_tx % TX_RING_SIZE;
@@ -339,18 +339,20 @@ epic100_transmit(struct nic *nic, const char *destaddr, unsigned int type,
      * set the base address with the "ownership"
      * bits last.
      */
-    
+   
     tx_ring[entry].buflength |= cpu_to_le32(len);
-    tx_ring[entry].status = cpu_to_le32(len << 16) | 
+    tx_ring[entry].status = cpu_to_le32(len << 16) |
 	    cpu_to_le32(TRING_OWN);	/* Pass ownership to the chip. */
 
     cur_tx++;
 
     /* Trigger an immediate transmit demand. */
-    outl(CR_QUEUE_TX, command); 
-    
-    load_timer2(10*TICKS_PER_MS);         /* timeout 10 ms for transmit */
-    while ((le32_to_cpu(tx_ring[entry].status) & (TRING_OWN)) && timer2_running())
+    outl(CR_QUEUE_TX, command);
+
+    ct = currticks();
+    /* timeout 10 ms for transmit */
+    while ((le32_to_cpu(tx_ring[entry].status) & (TRING_OWN)) &&
+		ct + 10*USECS_IN_MSEC < currticks())
 	/* Wait */;
 
     if ((le32_to_cpu(tx_ring[entry].status) & TRING_OWN) != 0)
diff --git a/src/drivers/net/etherfabric.c b/src/drivers/net/etherfabric.c
index 6b763451..90cc73f4 100644
--- a/src/drivers/net/etherfabric.c
+++ b/src/drivers/net/etherfabric.c
@@ -24,7 +24,6 @@
 #include <gpxe/i2c.h>
 #include <gpxe/spi.h>
 #include <gpxe/nvo.h>
-#include "timer.h"
 #define dma_addr_t unsigned long
 #include "etherfabric.h"
 
diff --git a/src/drivers/net/forcedeth.c b/src/drivers/net/forcedeth.c
index 9ef1dd79..f6195885 100644
--- a/src/drivers/net/forcedeth.c
+++ b/src/drivers/net/forcedeth.c
@@ -51,7 +51,6 @@
 #include <gpxe/pci.h>
 /* Include timer support functions */
 #include <gpxe/ethernet.h>
-#include "timer.h"
 #include "mii.h"
 
 #define drv_version "v1.2"
diff --git a/src/drivers/net/ipoib.c b/src/drivers/net/ipoib.c
index 905051bf..d457b258 100644
--- a/src/drivers/net/ipoib.c
+++ b/src/drivers/net/ipoib.c
@@ -22,7 +22,6 @@
 #include <string.h>
 #include <byteswap.h>
 #include <errno.h>
-#include "timer.h"
 #include <gpxe/if_arp.h>
 #include <gpxe/iobuf.h>
 #include <gpxe/netdevice.h>
diff --git a/src/drivers/net/mlx_ipoib/mt23108_imp.c b/src/drivers/net/mlx_ipoib/mt23108_imp.c
index 4e601668..bb2383c5 100644
--- a/src/drivers/net/mlx_ipoib/mt23108_imp.c
+++ b/src/drivers/net/mlx_ipoib/mt23108_imp.c
@@ -37,7 +37,6 @@ static void be_to_cpu_buf(void *buf, int size)
 	}
 }
 
-#include "timer.h"
 #include "cmdif_mt23108.c"
 #include "cmdif_comm.c"
 #include "ib_mt23108.c"
diff --git a/src/drivers/net/mlx_ipoib/mt25218_imp.c b/src/drivers/net/mlx_ipoib/mt25218_imp.c
index fe407041..007ee653 100644
--- a/src/drivers/net/mlx_ipoib/mt25218_imp.c
+++ b/src/drivers/net/mlx_ipoib/mt25218_imp.c
@@ -37,7 +37,6 @@ static void be_to_cpu_buf(void *buf, int size)
 	}
 }
 
-#include "timer.h"
 #include "cmdif_mt25218.c"
 #include "cmdif_comm.c"
 #include "ib_mt25218.c"
diff --git a/src/drivers/net/mtnic.c b/src/drivers/net/mtnic.c
index a568b2f7..536fcb8d 100755
--- a/src/drivers/net/mtnic.c
+++ b/src/drivers/net/mtnic.c
@@ -37,7 +37,7 @@
 #include <gpxe/umalloc.h>
 #include <bits/byteswap.h>
 #include <little_bswap.h>
-#include <timer.h>
+#include <unistd.h>
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
 #include <gpxe/netdevice.h>
diff --git a/src/drivers/net/natsemi.c b/src/drivers/net/natsemi.c
index 72047610..98a5ff84 100644
--- a/src/drivers/net/natsemi.c
+++ b/src/drivers/net/natsemi.c
@@ -63,8 +63,8 @@
 #include <stdio.h>
 #include <io.h>
 #include <errno.h>
-#include <timer.h>
 #include <byteswap.h>
+#include <unistd.h>
 #include <gpxe/pci.h>
 #include <gpxe/if_ether.h>
 #include <gpxe/ethernet.h>
diff --git a/src/drivers/net/pcnet32.c b/src/drivers/net/pcnet32.c
index e4318429..d8529da1 100644
--- a/src/drivers/net/pcnet32.c
+++ b/src/drivers/net/pcnet32.c
@@ -43,7 +43,6 @@
 #include "nic.h"
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
-#include "timer.h"
 #include "mii.h"
 
 /* void hex_dump(const char *data, const unsigned int len); */
diff --git a/src/drivers/net/prism2.c b/src/drivers/net/prism2.c
index 3c512519..aaf4c968 100644
--- a/src/drivers/net/prism2.c
+++ b/src/drivers/net/prism2.c
@@ -62,7 +62,6 @@ static const char hardcoded_ssid[] = "";
  * quicker to convert code from the Linux Prism2 driver.
  */
 #include <errno.h>
-#include "timer.h"
 #define __le16_to_cpu(x) (x)
 #define __le32_to_cpu(x) (x)
 #define __cpu_to_le16(x) (x)
diff --git a/src/drivers/net/r8169.c b/src/drivers/net/r8169.c
index 52cb0d0e..ab9a30f8 100644
--- a/src/drivers/net/r8169.c
+++ b/src/drivers/net/r8169.c
@@ -49,7 +49,6 @@
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
 #include <gpxe/malloc.h>
-#include "timer.h"
 
 #define drv_version "v1.6"
 #define drv_date "03-27-2004"
diff --git a/src/drivers/net/rtl8139.c b/src/drivers/net/rtl8139.c
index b4c99fcb..83fac554 100644
--- a/src/drivers/net/rtl8139.c
+++ b/src/drivers/net/rtl8139.c
@@ -71,7 +71,7 @@
 #include <stdio.h>
 #include <io.h>
 #include <errno.h>
-#include <timer.h>
+#include <unistd.h>
 #include <byteswap.h>
 #include <gpxe/pci.h>
 #include <gpxe/if_ether.h>
diff --git a/src/drivers/net/sis900.c b/src/drivers/net/sis900.c
index cf9b2ce6..58526506 100644
--- a/src/drivers/net/sis900.c
+++ b/src/drivers/net/sis900.c
@@ -46,7 +46,6 @@
 #include "etherboot.h"
 #include <gpxe/pci.h>
 #include "nic.h"
-#include "timer.h"
 
 #include "sis900.h"
 
diff --git a/src/drivers/net/smc9000.c b/src/drivers/net/smc9000.c
index c6219ee7..31a1e1b1 100644
--- a/src/drivers/net/smc9000.c
+++ b/src/drivers/net/smc9000.c
@@ -40,7 +40,6 @@
 #include "etherboot.h"
 #include "nic.h"
 #include <gpxe/isa.h>
-#include "timer.h"
 #include "smc9000.h"
 
 # define _outb outb
diff --git a/src/drivers/net/sundance.c b/src/drivers/net/sundance.c
index 3bbfbfbb..3b6f5a88 100644
--- a/src/drivers/net/sundance.c
+++ b/src/drivers/net/sundance.c
@@ -46,7 +46,6 @@
 #include "nic.h"
 /* to get the PCI support functions, if this is a PCI NIC */
 #include <gpxe/pci.h>
-#include "timer.h"
 #include "mii.h"
 
 #define drv_version "v1.12"
diff --git a/src/drivers/net/tg3.c b/src/drivers/net/tg3.c
index 43706bff..2aa072b6 100644
--- a/src/drivers/net/tg3.c
+++ b/src/drivers/net/tg3.c
@@ -17,7 +17,6 @@
 #include <errno.h>
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
-#include "timer.h"
 #include "string.h"
 #include "tg3.h"
 
diff --git a/src/drivers/net/tlan.c b/src/drivers/net/tlan.c
index 60ca182e..4fae0170 100644
--- a/src/drivers/net/tlan.c
+++ b/src/drivers/net/tlan.c
@@ -42,7 +42,6 @@
 #include "nic.h"
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
-#include "timer.h"
 #include "tlan.h"
 
 #define drv_version "v1.4"
diff --git a/src/drivers/net/via-rhine.c b/src/drivers/net/via-rhine.c
index 0c955fab..81350091 100644
--- a/src/drivers/net/via-rhine.c
+++ b/src/drivers/net/via-rhine.c
@@ -50,7 +50,6 @@ static const char *version = "rhine.c v1.0.2 2004-10-29\n";
 #include "nic.h"
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
-#include "timer.h"
 
 /* define all ioaddr */
 
@@ -785,6 +784,7 @@ ReadMII (int byMIIIndex, int ioaddr)
     char byMIIAdrbak;
     char byMIICRbak;
     char byMIItemp;
+    tick_t ct;
 
     byMIIAdrbak = inb (byMIIAD);
     byMIICRbak = inb (byMIICR);
@@ -799,8 +799,8 @@ ReadMII (int byMIIIndex, int ioaddr)
     byMIItemp = inb (byMIICR);
     byMIItemp = byMIItemp & 0x40;
 
-    load_timer2(2*TICKS_PER_MS);
-    while (byMIItemp != 0 && timer2_running())
+    ct = currticks();
+    while (byMIItemp != 0 && ct + 2*USECS_IN_MSEC < currticks())
     {
 	byMIItemp = inb (byMIICR);
 	byMIItemp = byMIItemp & 0x40;
@@ -825,6 +825,7 @@ WriteMII (char byMIISetByte, char byMIISetBit, char byMIIOP, int ioaddr)
     char byMIIAdrbak;
     char byMIICRbak;
     char byMIItemp;
+    tick_t ct;
 
 
     byMIIAdrbak = inb (byMIIAD);
@@ -840,8 +841,8 @@ WriteMII (char byMIISetByte, char byMIISetBit, char byMIIOP, int ioaddr)
     byMIItemp = inb (byMIICR);
     byMIItemp = byMIItemp & 0x40;
 
-    load_timer2(2*TICKS_PER_MS);
-    while (byMIItemp != 0 && timer2_running())
+    ct = currticks();
+    while (byMIItemp != 0 && ct + 2*USECS_IN_MSEC < currticks())
     {
 	byMIItemp = inb (byMIICR);
 	byMIItemp = byMIItemp & 0x40;
@@ -870,8 +871,8 @@ WriteMII (char byMIISetByte, char byMIISetBit, char byMIIOP, int ioaddr)
     byMIItemp = inb (byMIICR);
     byMIItemp = byMIItemp & 0x20;
 
-    load_timer2(2*TICKS_PER_MS);
-    while (byMIItemp != 0 && timer2_running())
+    ct = currticks();
+    while (byMIItemp != 0 && ct + 2*USECS_IN_MSEC < currticks())
     {
 	byMIItemp = inb (byMIICR);
 	byMIItemp = byMIItemp & 0x20;
@@ -1345,6 +1346,7 @@ rhine_transmit (struct nic *nic,
     unsigned char CR1bak;
     unsigned char CR0bak;
     unsigned int nstype;
+    tick_t ct;
 
 
     /*printf ("rhine_transmit\n"); */
@@ -1385,9 +1387,10 @@ rhine_transmit (struct nic *nic,
     outb (CR1bak, byCR1);
     do
     {
-        load_timer2(10*TICKS_PER_MS);
+	ct = currticks();
         /* Wait until transmit is finished or timeout*/
-        while((tp->tx_ring[entry].tx_status.bits.own_bit !=0) && timer2_running())
+        while((tp->tx_ring[entry].tx_status.bits.own_bit !=0) &&
+		ct + 10*USECS_IN_MSEC < currticks())
         ;
 
         if(tp->tx_ring[entry].tx_status.bits.terr == 0)
diff --git a/src/drivers/net/via-velocity.h b/src/drivers/net/via-velocity.h
index c296d289..a43028bd 100644
--- a/src/drivers/net/via-velocity.h
+++ b/src/drivers/net/via-velocity.h
@@ -24,8 +24,6 @@
  *       Copyright (c) 2006 by Timothy Legge <tlegge@rogers.com>
  */
 
-#include "timer.h"
-
 #ifndef VELOCITY_H
 #define VELOCITY_H
 
diff --git a/src/drivers/net/w89c840.c b/src/drivers/net/w89c840.c
index 2f141aa9..14497640 100644
--- a/src/drivers/net/w89c840.c
+++ b/src/drivers/net/w89c840.c
@@ -81,7 +81,6 @@
 #include "nic.h"
 #include <gpxe/pci.h>
 #include <gpxe/ethernet.h>
-#include "timer.h"
 
 static const char *w89c840_version = "driver Version 0.94 - December 12, 2003";
 
@@ -113,7 +112,7 @@ static const char *w89c840_version = "driver Version 0.94 - December 12, 2003";
 
 /* Operational parameters that usually are not changed. */
 /* Time in jiffies before concluding the transmitter is hung. */
-#define TX_TIMEOUT  (10*TICKS_PER_MS)
+#define TX_TIMEOUT  (10*USECS_IN_MSEC)
 
 #define PKT_BUF_SZ  1536  /* Size of each temporary Rx buffer.*/
 
@@ -487,6 +486,7 @@ static void w89c840_transmit(
     /* send the packet to destination */
     unsigned entry;
     int transmit_status;
+    tick_t ct;
 
     /* Caution: the write order is important here, set the field
        with the "ownership" bits last. */
@@ -535,8 +535,7 @@ static void w89c840_transmit(
     /* Now wait for TX to complete. */
     transmit_status = w840private.tx_ring[entry].status;
 
-    load_timer2(TX_TIMEOUT);
-
+    ct = currticks();
     {
 #if defined W89C840_DEBUG
         u32 intr_stat = 0;
@@ -547,7 +546,7 @@ static void w89c840_transmit(
 	      decode_interrupt(intr_stat);
 #endif
 
-                while ( (transmit_status & DescOwn) && timer2_running()) {
+                while ( (transmit_status & DescOwn) && ct + TX_TIMEOUT < currticks()) {
 
                     transmit_status = w840private.tx_ring[entry].status;
                 }
diff --git a/src/drivers/nvs/spi.c b/src/drivers/nvs/spi.c
index be6b5904..dbdc32f6 100644
--- a/src/drivers/nvs/spi.c
+++ b/src/drivers/nvs/spi.c
@@ -18,7 +18,7 @@
 
 #include <stddef.h>
 #include <errno.h>
-#include <timer.h>
+#include <unistd.h>
 #include <gpxe/spi.h>
 
 /** @file
diff --git a/src/drivers/nvs/threewire.c b/src/drivers/nvs/threewire.c
index 622e8585..dbecf909 100644
--- a/src/drivers/nvs/threewire.c
+++ b/src/drivers/nvs/threewire.c
@@ -18,7 +18,7 @@
 
 #include <stddef.h>
 #include <assert.h>
-#include <timer.h>
+#include <unistd.h>
 #include <gpxe/threewire.h>
 
 /** @file
diff --git a/src/hci/mucurses/kb.c b/src/hci/mucurses/kb.c
index 291ee6ac..cada7291 100644
--- a/src/hci/mucurses/kb.c
+++ b/src/hci/mucurses/kb.c
@@ -1,6 +1,6 @@
 #include <curses.h>
 #include <stddef.h>
-#include <timer.h>
+#include <unistd.h>
 #include "mucurses.h"
 
 /** @file
diff --git a/src/hci/shell_banner.c b/src/hci/shell_banner.c
index d313d4dd..62da487c 100644
--- a/src/hci/shell_banner.c
+++ b/src/hci/shell_banner.c
@@ -18,8 +18,8 @@
 
 #include <stdio.h>
 #include <console.h>
-#include <latch.h>
 #include <gpxe/features.h>
+#include <gpxe/timer.h>
 #include <gpxe/shell_banner.h>
 
 /** @file
diff --git a/src/include/etherboot.h b/src/include/etherboot.h
index 8d658194..2a465954 100644
--- a/src/include/etherboot.h
+++ b/src/include/etherboot.h
@@ -12,8 +12,8 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <strings.h>
-#include <latch.h>
 #include <console.h>
+#include <gpxe/timer.h>
 #include <gpxe/if_arp.h>
 #include <gpxe/if_ether.h>
 
diff --git a/src/include/gpxe/dhcp.h b/src/include/gpxe/dhcp.h
index 9a9ba748..6db0e026 100644
--- a/src/include/gpxe/dhcp.h
+++ b/src/include/gpxe/dhcp.h
@@ -12,7 +12,6 @@
 #include <gpxe/in.h>
 #include <gpxe/refcnt.h>
 #include <gpxe/tables.h>
-#include <latch.h>
 
 struct net_device;
 struct job_interface;
diff --git a/src/include/gpxe/tcp.h b/src/include/gpxe/tcp.h
index e2753120..264ec29b 100644
--- a/src/include/gpxe/tcp.h
+++ b/src/include/gpxe/tcp.h
@@ -9,7 +9,6 @@
  *
  */
 
-#include "latch.h"
 #include <gpxe/tcpip.h>
 
 /**
diff --git a/src/include/gpxe/timer.h b/src/include/gpxe/timer.h
new file mode 100644
index 00000000..4a4cf5b2
--- /dev/null
+++ b/src/include/gpxe/timer.h
@@ -0,0 +1,32 @@
+#ifndef	GPXE_TIMER_H
+#define GPXE_TIMER_H
+
+#include <stddef.h>
+
+typedef uint32_t tick_t;
+
+#define MSECS_IN_SEC (1000)
+#define USECS_IN_SEC (1000*1000)
+#define USECS_IN_MSEC (1000)
+
+#define	TICKS_PER_SEC	USECS_IN_SEC
+
+tick_t currticks(void);
+
+void generic_currticks_udelay(unsigned int usecs);
+
+struct timer {
+	/* Returns zero on successful initialisation. */
+	int (*init) (void);
+
+	/* Return the current time, int mictoseconds since the beginning. */
+	tick_t (*currticks) (void);
+
+	/* Sleep for a few useconds. */
+	void (*udelay) (unsigned int useconds);
+};
+
+#define __timer(order) __table (struct timer, timers, order)
+
+#endif	/* GPXE_TIMER_H */
+
diff --git a/src/include/timer.h b/src/include/timer.h
deleted file mode 100644
index 0044d0c0..00000000
--- a/src/include/timer.h
+++ /dev/null
@@ -1,61 +0,0 @@
-/* Defines for routines to implement a low-overhead timer for drivers */
-
- /*
- * 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.
- */
-
-#ifndef	TIMER_H
-#define TIMER_H
-
-/* 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
-
-#define	BINARY_COUNT	0x00
-#define	BCD_COUNT	0x01
-
-/* Timers tick over at this rate */
-#define CLOCK_TICK_RATE	1193180U
-#define	TICKS_PER_MS	(CLOCK_TICK_RATE/1000)
-
-/* 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 */
-
-/* Ticks must be between 0 and 65535 (0 == 65536)
-   because it is a 16 bit counter */
-extern void load_timer2(unsigned int ticks);
-extern inline int timer2_running(void);
-extern void waiton_timer2(unsigned int ticks);
-
-extern void ndelay(unsigned int nsecs);
-extern void udelay(unsigned int usecs);
-extern void mdelay(unsigned int msecs);
-
-
-#endif	/* TIMER_H */
diff --git a/src/include/unistd.h b/src/include/unistd.h
index 35dcf584..7c44a0ce 100644
--- a/src/include/unistd.h
+++ b/src/include/unistd.h
@@ -4,7 +4,7 @@
 #include <stddef.h>
 #include <stdarg.h>
 
-extern unsigned int sleep ( unsigned int seconds );
+unsigned int sleep ( unsigned int seconds );
 extern int execv ( const char *command, char * const argv[] );
 
 /**
@@ -22,4 +22,10 @@ extern int execv ( const char *command, char * const argv[] );
 		rc;							\
 	} )
 
+void udelay(unsigned int usecs);
+void mdelay(unsigned int msecs);
+
+#define usleep(x) udelay(x)
+
+
 #endif /* _UNISTD_H */
diff --git a/src/net/retry.c b/src/net/retry.c
index 0f711e6d..90b89711 100644
--- a/src/net/retry.c
+++ b/src/net/retry.c
@@ -17,7 +17,7 @@
  */
 
 #include <stddef.h>
-#include <latch.h>
+#include <gpxe/timer.h>
 #include <gpxe/list.h>
 #include <gpxe/process.h>
 #include <gpxe/init.h>
diff --git a/src/net/tcp.c b/src/net/tcp.c
index d6b44b02..da8e87b4 100644
--- a/src/net/tcp.c
+++ b/src/net/tcp.c
@@ -4,7 +4,7 @@
 #include <assert.h>
 #include <errno.h>
 #include <byteswap.h>
-#include <timer.h>
+#include <gpxe/timer.h>
 #include <gpxe/iobuf.h>
 #include <gpxe/malloc.h>
 #include <gpxe/retry.h>
diff --git a/src/net/udp/dhcp.c b/src/net/udp/dhcp.c
index 081fa841..2cb258e4 100644
--- a/src/net/udp/dhcp.c
+++ b/src/net/udp/dhcp.c
@@ -33,6 +33,7 @@
 #include <gpxe/ip.h>
 #include <gpxe/uuid.h>
 #include <gpxe/dhcp.h>
+#include <gpxe/timer.h>
 
 /** @file
  *