1.s3c6410_init()被调用的流程:
cpu赋值流程:
1).定义cpu, __mach_desc_MACH_TYPE_SMDK6410
static struct cpu_table *cpu;

#define MACHINE_START(_type,_name)            
static const struct machine_desc __mach_desc_##_type    
 __used                            
 __attribute__((__section__(".arch.info.init"))) = {    
    .nr        = MACH_TYPE_##_type,        
    .name        = _name,

#define MACHINE_END                
};

static const struct machine_desc __mach_desc_SMDK6410
.nr = MACH_TYPE_SMDK6410
.name = "SMDK6410"

2).
machine_arch_type==MACH_TYPE_SMDK6410==1626

MACHINE_START(SMDK6410, "SMDK6410")
    ......................,
    .init_irq   = s3c_init_irq,
    .map_io     = smdk6410_map_io,
    .fixup      = smdk6410_fixup,
    .timer      = &s3c_timer,
    .init_machine   = smdk6410_machine_init,
MACHINE_END

start_kernel()==>setup_arch()===>
1.mdesc=setup_machine(machine_arch_type)==>lookup_machine_types(MACH_TYPE_SMDK6410) == __mach_desc_SMDK6410
2.paging_init(mdesc) ==>devicemaps_init(mdesc) ==> mdesc->map_io()==>__mach_desc_SMDK6410->map_io()
    ==>smdk6410_map_io() ==> s3c24xx_init_io() ==> cpu = s3c_lookup_cpu(idcode);

调用流程:
arch_initcall(s3c_arch_init)==>s3c_arch_init()==>(cpu->init)()==>s3c6410_init()