最近，又研究了一下qemu-uboot-kernel这套代码，发现了只需要修改两个地方就可以使qemu支持256M以及以上容量的NAND FLASH,?

一、
# vim qemu_src/hw/mini2440.c
找到下面这第372行代码:
????/* Check the boot mode */
????switch (mini->boot_mode) {
????????case BOOT_NAND:
????????????sram_base = S3C_SRAM_BASE_NANDBOOT;
????????????int size = bdrv_getlength(drives_table[nand_idx].bdrv);
????????????switch (size) {
????????????????case 2 * 65536 * (512 + 16):
????????????????????nand_cid = 0x76;
????????????????????break;
????????????????case 4 * 65536 * (512 + 16):
????????????????????nand_cid = 0xf1;
????????????????default:
????????????????????printf("%s: Unknown NAND size/id %d (%dMB) defaulting to old 64MBn",
????????????????????????????__func__,size,((size / (512 + 16)) * 512) / 1024 / 1024);
????????????}
????????????break;
在default: 语句上方加入下面这三行：
????????case 8 * 65536 * (512 + 16):
????????????????????nand_cid = 0xda;?????????????????????? // 256MB flash == 0xda
如果要支持比如 512M 容量的 NAND FLASH ， 那么可以模仿上面的代码，跟着加入下面三行：
? ? ? ? case 16 * 65536 * (512 + 16):
????????????????????nand_cid = 0xdc;?????????????????????? // 512MB flash == 0xdc
至于里面为什么是 512 +16 ，可以看看这个网页：http://bbs.eeworld.com.cn/thread-305322-1-1.html
至于 0xda 是什么东西，可以看看 qemu_src/nand.c 中下面这些内容：
/* Information based on Linux drivers/mtd/nand/nand_ids.c */
static const struct {
????int size;
????int width;
????int page_shift;
????int erase_shift;
????uint32_t options;
} nand_flash_ids[0x100] = {
................................
? ? [0x76] = { 64,8,9,5,0 },51); font-family:Arial; font-size:14px; line-height:28px; text-align:left">??/*
???? * These are the new chips with large page size. The pagesize and the
???? * erasesize is determined from the extended id bytes
???? */
# define LP_OPTIONS????(NAND_SAMSUNG_LP | NAND_NO_READRDY | NAND_NO_AUTOINCR)
# define LP_OPTIONS16????(LP_OPTIONS | NAND_BUSWIDTH_16)
......................................................................
? /* 1 Gigabit */? ????? [0xa1] = { 128,LP_OPTIONS },? ????? [0xf1] = { 128,? ?? ? [0xb1] = { 128,16,LP_OPTIONS16 },??? ? ?[0xc1] = { 128,51); font-family:Arial; font-size:14px; line-height:28px; text-align:left">????/* 2 Gigabit */
????[0xaa] = { 256,????8,????0,51); font-family:Arial; font-size:14px; line-height:28px; text-align:left">????[0xda] = { 256,51); font-family:Arial; font-size:14px; line-height:28px; text-align:left">................................................................
二、
还要修改一个文件，那就是?
vim qemu_src/mini2440/mini2440_start.sh?
修改为以下内容:
echo Starting in $base
#name_nand="$base/mini2440_nand64.bin"
#name_nand="$base/mini2440_nand128.bin"
name_nand="$base/mini2440_nand256.bin"
if [ ! -f "$name_nand" ];then
?echo $0 : creating NAND empty image : "$name_nand"
# dd if=/dev/zero of="$name_nand" bs=528 count=131072
# dd if=/dev/zero of="$name_nand" bs=2112 count=65536?
dd if=/dev/zero of="$name_nand" bs=135168 count=2048
..........................................................
至于为什么bs 和 count 要取那些值，可以看看这个?http://blog.163.com/chenfang7977@yeah/blog/static/128274196201008101048689/
三、修改完上述两个文件，然后，再重新把 qemu 编译一遍，就可以使用命令 ?sudo sh mini2440/mini2440_start.sh ?来重新启动 qemu-uboot-mini2440了

上传个启动?125M 的 最新版 rootfs_qtopia_qt4 的图片: