IO_SIZE
.length = IO_SIZE,
memcpy(dst_pgd, src_pgd, sizeof(pgd_t) * (IO_SIZE / PGDIR_SIZE));
flush_tlb_range(&vma, IO_START, IO_START + IO_SIZE);
.length = IO_SIZE ,
area->size = size + IO_SIZE;
addr = (void *)((unsigned long)addr & -IO_SIZE);
__free_io_area(tmp->addr, tmp->size - IO_SIZE);
offset = physaddr & (IO_SIZE - 1);
physaddr &= -IO_SIZE;
size = (size + offset + IO_SIZE - 1) & -IO_SIZE;
if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
release_region(base, IO_SIZE);
release_region(base, IO_SIZE);