Initial revision

src/arch/i386/firmware/pcbios/bios.c

@@ -0,0 +1,155 @@
+/* Etherboot routines for PCBIOS firmware.
+ *
+ * Body of routines taken from old pcbios.S
+ */
+
+#ifdef PCBIOS
+
+#include "etherboot.h"
+#include "realmode.h"
+#include "segoff.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 = VIRTUAL(0x0040,0x006c);
+	uint8_t *midnight = VIRTUAL(0x0040,0x0070);
+
+	/* Re-enable interrupts so that the timer interrupt can occur
+	 */
+	RM_FRAGMENT(rm_currticks,
+		"sti\n\t"
+		"nop\n\t"
+		"nop\n\t"
+		"cli\n\t"
+	);	
+
+	real_call ( rm_currticks, NULL, NULL );
+
+	if ( *midnight ) {
+		*midnight = 0;
+		days += 0x1800b0;
+	}
+	return ( days + *ticks );
+}
+#endif	/* CONFIG_BIOS_CURRTICKS */
+
+/**************************************************************************
+INT15 - Call Interrupt 0x15
+**************************************************************************/
+int int15 ( int ax )
+{
+	struct {
+		reg16_t ax;
+	} PACKED in_stack;
+	struct {
+		reg16_t flags;
+	} PACKED out_stack;
+	reg16_t ret_ax;
+
+	RM_FRAGMENT(rm_int15,
+		"sti\n\t"
+		"popw %ax\n\t"
+		"stc\n\t"
+		"int $0x15\n\t"
+		"pushf\n\t"
+		"cli\n\t"
+	);
+
+	in_stack.ax.word = ax;
+	ret_ax.word = real_call ( rm_int15, &in_stack, &out_stack );
+
+	/* Carry flag clear indicates function not supported */
+	if ( ! ( out_stack.flags.word & CF ) ) return 0;
+	return ret_ax.h;
+}
+
+#ifdef	POWERSAVE
+/**************************************************************************
+CPU_NAP - Save power by halting the CPU until the next interrupt
+**************************************************************************/
+void cpu_nap ( void )
+{
+	RM_FRAGMENT(rm_cpu_nap,
+		"sti\n\t"
+		"hlt\n\t"
+		"cli\n\t"
+	);	
+
+	real_call ( rm_cpu_nap, NULL, NULL );
+}
+#endif	/* POWERSAVE */
+
+#if	(TRY_FLOPPY_FIRST > 0)
+/**************************************************************************
+DISK_INIT - Initialize the disk system
+**************************************************************************/
+void disk_init ( void )
+{
+	RM_FRAGMENT(rm_disk_init,
+		"sti\n\t"
+		"xorw %ax,%ax\n\t"
+		"movb $0x80,%dl\n\t"
+		"int $0x13\n\t"
+		"cli\n\t"
+	);
+	
+	real_call ( rm_disk_init, NULL, NULL );
+}
+
+/**************************************************************************
+DISK_READ - Read a sector from disk
+**************************************************************************/
+unsigned int pcbios_disk_read ( int drive, int cylinder, int head, int sector,
+				char *buf ) {
+	struct {
+		reg16_t ax;
+		reg16_t cx;
+		reg16_t dx;
+		segoff_t buffer;
+	} PACKED in_stack;
+	struct {
+		reg16_t flags;
+	} PACKED out_stack;
+	reg16_t ret_ax;
+
+	RM_FRAGMENT(rm_pcbios_disk_read,
+		"sti\n\t"
+		"popw %ax\n\t"
+		"popw %cx\n\t"
+		"popw %dx\n\t"
+		"popw %bx\n\t"
+		"popw %es\n\t"
+		"int $0x13\n\t"
+		"pushfw\n\t"
+		"cli\n\t"
+	);
+
+	in_stack.ax.h = 2; /* INT 13,2 - Read disk sector */
+	in_stack.ax.l = 1; /* Read one sector */
+	in_stack.cx.h = cylinder & 0xff;
+	in_stack.cx.l = ( ( cylinder >> 8 ) & 0x3 ) | sector;
+	in_stack.dx.h = head;
+	in_stack.dx.l = drive;
+	in_stack.buffer.segment = SEGMENT ( buf );
+	in_stack.buffer.offset = OFFSET ( buf );
+	ret_ax.word = real_call ( rm_pcbios_disk_read, &in_stack, &out_stack );
+	return ( out_stack.flags.word & CF ) ? ret_ax.word : 0;
+}
+#endif /* TRY_FLOPPY_FIRST */
+
+#endif /* PCBIOS */