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>

src/core/config.c

@@ -74,6 +74,17 @@ REQUIRE_OBJECT ( pc_kbd );
 REQUIRE_OBJECT ( syslog );
 #endif
 
+/*
+ * Timers
+ */
+
+#ifdef TIMER_BIOS
+REQUIRE_OBJECT ( timer_bios );
+#endif
+
+#ifdef TIMER_RTDSC
+REQUIRE_OBJECT ( timer_rtdsc );
+#endif
 /*
  * Drag in all requested protocols
  *

src/core/misc.c

@@ -7,18 +7,6 @@ MISC Support Routines
 #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;
-}
-
 /**************************************************************************
 INET_ATON - Convert an ascii x.x.x.x to binary form
 **************************************************************************/

src/core/timer.c

@@ -1,27 +1,104 @@
-/* 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 );
+
+
+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)
+{
+	tick_t t;
+
+	t = currticks();
+	while (t + usecs > currticks())
+		; /* xxx: Relax the cpu some way. */
+}
+
+
+static void timer_init(void)
+{
+	struct timer *ts;
+
+	for (ts = ts_table; ts < ts_table_end; ts++) {
+		if (ts->init && !ts->init()) {
+			used_ts = ts;
+			break;
+		}
+	}
+
+	if (!used_ts) {
+		printf("No timer available. This should never happen. Expect gPXE to die soon.\n");
+		/* Panic */
+	}
+
+}
+
+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)
 {
-	unsigned int i;
-	for(i = 0; i < msecs; i++) {
-		udelay(1000);
-	}
+	while(msecs--)
+		used_ts->udelay(USECS_IN_MSEC);
 }
 
-void waiton_timer2(unsigned int ticks)
+unsigned int sleep(unsigned int secs)
 {
-	load_timer2(ticks);
-	while(timer2_running()) {
-	}
+	while (secs--)
+		mdelay(MSECS_IN_SEC);
+
+	return 0;
 }
+