TQ210 NAND驱动移植

我在移植NAND驱动时遇到了问题：系统启动后，能正确识别NAND并读写正常，但后面读写就出问题：
[    0.512779] nand: device found, Manufacturer ID: 0xec, Chip ID: 0xd3
[    0.518168] nand: Samsung NAND 1GiB 3,3V 8-bit
[    0.522562] nand: 1024 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64
[    0.530189] nand: NAND_ECC_NONE selected by board driver. This is not recommended!
[    0.537725] Scanning device for bad blocks
[    0.668335] Bad eraseblock 1402 at 0x00000af40000
[    1.276437] s3c_nand_init_later
[    1.276509] 3 ofpart partitions found on MTD device b0e00000.nand
[    1.276563] Creating 3 MTD partitions on "b0e00000.nand":
[    1.276615] 0x000000000000-0x000000040000 : "u-boot"
[    1.278081] 0x000000040000-0x000000060000 : "u-boot-env"
[    1.280363] 0x000000060000-0x000040000000 : "firmware"
[   13.332152] 2 uimage-fw partitions found on MTD device firmware
[   13.332224] 0x000000060000-0x0000001b9e2d : "kernel"
[   13.333680] 0x0000001b9e2d-0x000040000000 : "rootfs"
[   13.336269] mtd: device 4 (rootfs) set to be root filesystem
[   13.336346] 1 squashfs-split partitions found on MTD device rootfs
[   13.337469] 0x0000002e0000-0x000040000000 : "rootfs_data"
[   13.347097] NET: Registered protocol family 10
[   13.349651] NET: Registered protocol family 17
[   13.759200] nand: timeout while waiting for chip to become ready
[   14.159199] nand: timeout while waiting for chip to become ready
[   14.159687] squashfs: SQUASHFS error: unable to read inode lookup table
[   14.160012] jffs2: Flash size not aligned to erasesize, reducing to 1046784KiB
[   14.559199] nand: timeout while waiting for chip to become ready
[   14.959195] nand: timeout while waiting for chip to become ready
[   15.359195] nand: timeout while waiting for chip to become ready
[   15.759195] nand: timeout while waiting for chip to become ready
[   16.159195] nand: timeout while waiting for chip to become ready
[   16.559195] nand: timeout while waiting for chip to become ready
[   16.959195] nand: timeout while waiting for chip to become ready
[   17.359195] nand: timeout while waiting for chip to become ready