[nap] Formalise the CPU sleeping API

src/arch/i386/core/nap.c

-
-#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" ) : : );
-}

src/arch/i386/include/bios.h

 #define BDA_FBMS 0x0013
 #define BDA_NUM_DRIVES 0x0075
 
-extern void cpu_nap ( void );
-
 #endif /* BIOS_H */

src/arch/i386/include/bits/nap.h

+#ifndef _BITS_NAP_H
+#define _BITS_NAP_H
+
+/** @file
+ *
+ * i386-specific CPU sleeping API implementations
+ *
+ */
+
+#include <gpxe/bios_nap.h>
+
+#endif /* _BITS_MAP_H */

src/arch/i386/include/gpxe/bios_nap.h

+#ifndef _GPXE_BIOS_NAP_H
+#define _GPXE_BIOS_NAP_H
+
+/** @file
+ *
+ * BIOS CPU sleeping
+ *
+ */
+
+#ifdef NAP_PCBIOS
+#define NAP_PREFIX_pcbios
+#else
+#define NAP_PREFIX_pcbios __pcbios_
+#endif
+
+#endif /* _GPXE_BIOS_NAP_H */

src/arch/i386/interface/pcbios/bios_nap.c

+#include <gpxe/nap.h>
+#include <realmode.h>
+
+/**
+ * Save power by halting the CPU until the next interrupt
+ *
+ */
+static void bios_cpu_nap ( void ) {
+	__asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
+					   "hlt\n\t"
+					   "cli\n\t" ) : : );
+}
+
+PROVIDE_NAP ( pcbios, cpu_nap, bios_cpu_nap );

src/config/defaults/pcbios.h

 #define PCIAPI_PCBIOS
 #define TIMER_PCBIOS
 #define CONSOLE_PCBIOS
+#define NAP_PCBIOS
 
 #endif /* CONFIG_DEFAULTS_PCBIOS_H */

src/config/nap.h

+#ifndef CONFIG_NAP_H
+#define CONFIG_NAP_H
+
+/** @file
+ *
+ * CPU sleeping
+ *
+ */
+
+#include <config/defaults.h>
+
+//#undef		NAP_PCBIOS
+//#define		NAP_NULL
+
+#endif /* CONFIG_NAP_H */

src/core/console.c

 #include "stddef.h"
 #include "console.h"
 #include <gpxe/process.h>
+#include <gpxe/nap.h>
 
 /** @file */
 
-#include "bios.h"
-
 static struct console_driver console_drivers[0]
 	__table_start ( struct console_driver, console );
 static struct console_driver console_drivers_end[0]
  *
  * The character read will not be echoed back to any console.
  *
- * @bug We need a cleaner way to pick up cpu_nap().  It makes a
- * real-mode call, and so we don't want to use it with LinuxBIOS.
- *
  */
 int getchar ( void ) {
 	struct console_driver *console;

src/core/gdbudp.c

 #include <stdio.h>
 #include <string.h>
 #include <byteswap.h>
-#include <bios.h>
 #include <gpxe/iobuf.h>
 #include <gpxe/in.h>
 #include <gpxe/if_arp.h>
 #include <gpxe/ip.h>
 #include <gpxe/udp.h>
 #include <gpxe/netdevice.h>
+#include <gpxe/nap.h>
 #include <gpxe/gdbstub.h>
 #include <gpxe/gdbudp.h>
 

src/core/null_nap.c

+#include <gpxe/nap.h>
+
+PROVIDE_NAP_INLINE ( null, cpu_nap );

src/include/gpxe/nap.h

+#ifndef _GPXE_NAP_H
+#define _GPXE_NAP_H
+
+/** @file
+ *
+ * CPU sleeping
+ *
+ */
+
+#include <gpxe/api.h>
+#include <config/nap.h>
+
+/**
+ * Calculate static inline CPU sleeping API function name
+ *
+ * @v _prefix		Subsystem prefix
+ * @v _api_func		API function
+ * @ret _subsys_func	Subsystem API function
+ */
+#define NAP_INLINE( _subsys, _api_func ) \
+	SINGLE_API_INLINE ( NAP_PREFIX_ ## _subsys, _api_func )
+
+/**
+ * Provide an CPU sleeping API implementation
+ *
+ * @v _prefix		Subsystem prefix
+ * @v _api_func		API function
+ * @v _func		Implementing function
+ */
+#define PROVIDE_NAP( _subsys, _api_func, _func ) \
+	PROVIDE_SINGLE_API ( NAP_PREFIX_ ## _subsys, _api_func, _func )
+
+/**
+ * Provide a static inline CPU sleeping API implementation
+ *
+ * @v _prefix		Subsystem prefix
+ * @v _api_func		API function
+ */
+#define PROVIDE_NAP_INLINE( _subsys, _api_func ) \
+	PROVIDE_SINGLE_API_INLINE ( NAP_PREFIX_ ## _subsys, _api_func )
+
+/* Include all architecture-independent I/O API headers */
+#include <gpxe/null_nap.h>
+
+/* Include all architecture-dependent I/O API headers */
+#include <bits/nap.h>
+
+/**
+ * Sleep until next CPU interrupt
+ *
+ */
+void cpu_nap ( void );
+
+#endif /* _GPXE_NAP_H */

src/include/gpxe/null_nap.h

+#ifndef _GPXE_NULL_NAP_H
+#define _GPXE_NULL_NAP_H
+
+/** @file
+ *
+ * Null CPU sleeping
+ *
+ */
+
+#ifdef NAP_NULL
+#define NAP_PREFIX_null
+#else
+#define NAP_PREFIX_null __null_
+#endif
+
+static inline __always_inline void
+NAP_INLINE ( null, cpu_nap ) ( void ) {
+	/* Do nothing */
+}
+
+#endif /* _GPXE_NULL_NAP_H */