sgi_mace
extern struct sgi_mace __iomem *mace;
struct sgi_mace __iomem *mace;
mace = ioremap(MACE_BASE, sizeof(struct sgi_mace));
#define MACEISA_SERIAL1_OFFS offsetof(struct sgi_mace, isa.serial1)
#define MACEISA_SERIAL2_OFFS offsetof(struct sgi_mace, isa.serial2)
#define MACE_RTC_RES_START (MACE_BASE + offsetof(struct sgi_mace, isa.rtc))
p->base = MACE_BASE + offsetof(struct sgi_mace, isa.parallel);
p->base_hi = MACE_BASE + offsetof(struct sgi_mace, isa.ecp1284);