memblock memory type和reserve type region的添加

memblock从类型上面来分，分为三类：memory, reserve和physmem.常见的就是普通的memory和reserve的memory。

struct memblock {bool bottom_up;  /* is bottom up direction? */phys_addr_t current_limit;struct memblock_type memory;struct memblock_type reserved;#ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAPstruct memblock_type physmem;#endif};

首先从start_kernel->setup_arch->setup_machine_fdt()进行FDT的扫描。

static void __init setup_machine_fdt(phys_addr_t dt_phys){void *dt_virt = fixmap_remap_fdt(dt_phys);if (!dt_virt || !early_init_dt_scan(dt_virt)) {pr_crit("\n""Error: invalid device tree blob at physical address %pa (virtual address 0x%p)\n""The dtb must be 8-byte aligned and must not exceed 2 MB in size\n""\nPlease check your bootloader.",&dt_phys, dt_virt);while (true)cpu_relax();}dump_stack_set_arch_desc("%s (DT)", of_flat_dt_get_machine_name());}

在此函数中将FDT的物理地址通过fixmap_remap_fdt转化为虚拟地址，然后通过early_init_dt_scan->early_init_dt_scan_nodes函数来遍历整个FDT。

void __init early_init_dt_scan_nodes(void){/* Retrieve various information from the /chosen node */of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);/* Initialize {size,address}-cells info */of_scan_flat_dt(early_init_dt_scan_root, NULL);/* Setup memory, calling early_init_dt_add_memory_arch */of_scan_flat_dt(early_init_dt_scan_memory, NULL);}

首先通过of_scan_flat_dt针对FDT的每一个node执行callback函数。

early_init_dt_scan_chosen函数主要是找到chosen节点并将相关参数写到boot_command_line中去。

early_init_dt_scan_root函数获取root节点的size_cell和addr_cell的值。

early_init_dt_scan_memory获取memory节点的reg属性中的起始地址和大小，并通过early_init_dt_add_memory_arch函数添加到memory type的memblock中去。