ref: 14cfa56253beb8a2ad8e4700c8c26a6ff6d16ee7
dir: /sys/src/9/arm64/io.h/
enum {
	IRQfiq		= -1,
	PPI		= 16,
	SPI		= 32,
	IRQcntvns	= PPI+11,
	IRQuart		= SPI+1,
	IRQpci1		= SPI+3,
	IRQpci2		= SPI+4,
	IRQpci3		= SPI+5,
	IRQpci4		= SPI+6,
};
#define BUSUNKNOWN (-1)
#define PCIWINDOW	0
#define	PCIWADDR(x)	(PADDR(x)+PCIWINDOW)