[Timers] Miscellaneous timer system fixes

Add missing comments to timer code.

Lock system if no suitable timer source is found.

Fix initialisation order so that timers are initialised before code that
needs to use them.

src/core/serial.c

  * early debug messages.  It is safe to call serial_init() multiple
  * times.
  */
-struct init_fn serial_init_fn __init_fn ( INIT_EARLY ) = {
+struct init_fn serial_init_fn __init_fn ( INIT_CONSOLE ) = {
 	.initialise = serial_init,
 };

src/core/timer.c

 #include <assert.h>
 #include <gpxe/init.h>
 #include <gpxe/timer.h>
-#include <stdio.h>
 
 static struct timer ts_table[0]
 	__table_start ( struct timer, timers );
 	struct timer *ts;
 
 	for (ts = ts_table; ts < ts_table_end; ts++) {
-		if (ts->init && ts->init() >= 0) {
+		if ( ts->init() == 0 ) {
 			used_ts = ts;
-			break;
+			return;
 		}
 	}
 
-	assert(used_ts);
+	/* No timer found; we cannot continue */
+	assert ( 0 );
+	while ( 1 ) {};
 }
 
 struct init_fn ts_init_fn __init_fn ( INIT_NORMAL ) = {
 	.initialise = timer_init,
 };
 
-/* Functions for public use. */
-
-tick_t currticks(void)
-{
+/**
+ * Read current time
+ *
+ * @ret ticks	Current time, in ticks
+ */
+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);
+	DBG ( "currticks: %ld.%06ld seconds\n",
+	      ct / USECS_IN_SEC, ct % USECS_IN_SEC );
 
 	return ct;
 }
 
-void udelay(unsigned int usecs)
-{
-	used_ts->udelay(usecs);
+/**
+ * Delay
+ *
+ * @v usecs	Time to delay, in microseconds
+ */
+void udelay ( unsigned int usecs ) {
+	assert(used_ts);
+	used_ts->udelay ( usecs );
 }
 
-void mdelay(unsigned int msecs)
-{
-	while(msecs--)
-		used_ts->udelay(USECS_IN_MSEC);
+/**
+ * Delay
+ *
+ * @v msecs	Time to delay, in milliseconds
+ */
+void mdelay ( unsigned int msecs ) {
+	while ( msecs-- )
+		udelay ( USECS_IN_MSEC );
 }
 
-unsigned int sleep(unsigned int secs)
-{
-	while (secs--)
-		mdelay(MSECS_IN_SEC);
-
+/**
+ * Delay
+ *
+ * @v secs	Time to delay, in seconds
+ */
+unsigned int sleep ( unsigned int secs ) {
+	while ( secs-- )
+		mdelay ( MSECS_IN_SEC );
 	return 0;
 }
-

src/include/gpxe/init.h

  */
 
 #define INIT_EARLY	01	/**< Early initialisation */
-#define INIT_NORMAL	02	/**< Normal initialisation */
+#define	INIT_CONSOLE	02	/**< Console initialisation */
+#define INIT_NORMAL	03	/**< Normal initialisation */
 
 /** @} */
 
 
 /** @} */
 
-/* Use double digits to avoid problems with "10" < "9" on alphabetic sort */
-#define	INIT_CONSOLE	02
-#define	INIT_GDBSYM	03
-#define	INIT_CPU	04
-#define	INIT_TIMERS	05
-#define	INIT_LOADBUF	08
-#define	INIT_PCMCIA	09
-
 extern void initialise ( void );
 extern void startup ( void );
 extern void shutdown ( void );

src/include/gpxe/timer.h

 
 #include <stddef.h>
 
-typedef uint32_t tick_t;
+typedef unsigned long tick_t;
 
 #define MSECS_IN_SEC (1000)
 #define USECS_IN_SEC (1000*1000)
 
 #define	TICKS_PER_SEC	USECS_IN_SEC
 
-tick_t currticks(void);
+extern tick_t currticks ( void );
 
-void generic_currticks_udelay(unsigned int usecs);
+extern void generic_currticks_udelay ( unsigned int usecs );
 
+/** A timer */
 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);
+	/** Initialise timer
+	 *
+	 * @ret rc	Return status code
+	 */
+	int ( * init ) ( void );
+	/** Read current time
+	 *
+	 * @ret ticks	Current time, in ticks
+	 */
+	tick_t ( * currticks ) ( void );
+	/** Delay
+	 *
+	 * @v usecs	Time to delay, in microseconds
+	 */
+	void ( * udelay ) ( unsigned int usecs );
 };
 
-#define __timer(order) __table (struct timer, timers, order)
+#define __timer( order ) __table ( struct timer, timers, order )
 
 #endif	/* GPXE_TIMER_H */