为什么友善官方移植的linux-2.6.29中的mach-mini2440.c中mini2440_iodesc[]是空的

为什么友善官方移植的linux-2.6.29中的mach-mini2440.c中mini2440_iodesc[]是空的
static struct map_desc mini2440_iodesc[] __initdata = {
};
而mach-smdk2440.c中是这样的，
static struct map_desc smdk2440_iodesc[] __initdata = {
    /* ISA IO Space map (memory space selected by A24) */

    {
        .virtual    = (u32)S3C24XX_VA_ISA_WORD,
        .pfn        = __phys_to_pfn(S3C2410_CS2),
        .length        = 0x10000,
        .type        = MT_DEVICE,
    }, {
        .virtual    = (u32)S3C24XX_VA_ISA_WORD + 0x10000,
        .pfn        = __phys_to_pfn(S3C2410_CS2 + (1<<24)),
        .length        = SZ_4M,
        .type        = MT_DEVICE,
    }, {
        .virtual    = (u32)S3C24XX_VA_ISA_BYTE,
        .pfn        = __phys_to_pfn(S3C2410_CS2),
        .length        = 0x10000,
        .type        = MT_DEVICE,
    }, {
        .virtual    = (u32)S3C24XX_VA_ISA_BYTE + 0x10000,
        .pfn        = __phys_to_pfn(S3C2410_CS2 + (1<<24)),
        .length        = SZ_4M,
        .type        = MT_DEVICE,
    }
};