基于AT91SAM9X35EK的嵌入式Linux+UBI根文件系统移植成功

经过近一个月的学习与实践，终于在AT91SAM9X35EK开发板上跑起了Linux系统，用的是UBI文件系统，开发环境与不断的编译、查找资料、烧写验证，下载相关的软件，占了很多的时间，不过不断的克服困难，就能不断的前进。路很长，但需要耐心不断走下去。

开发环境为：

CentOS6.5 Linux虚拟机。

硬件为：AT91SAM9X35EK

NandFlash启动（Bootstrap+Uboot+Linux Kernel+UBI根文件系统全烧写在NandFlash中）。

使用较新的AT91Bootstrap与Uboot。

使用较新的稳定的Linux version 2.6.39（ATmel官方提供AT91SAM9X35EK的相关文件，方便移植）。

时间主要卡在了文件系统制作与支持上，总是不成功，原因是PMECC校验要打开，烧写文件系统时，还需要加上一个Trimffs的选项（我这里使用Jlink+SAMBA2.15烧写所有的文件）。



以下为运行起来的控制台信息。

AT91Bootstrap 3.6.0

NAND: Done to load image

U-Boot 2014.04 (Feb 15 2016 - 14:56:42)

CPU: AT91SAM9X35

Crystal frequency: 12 MHz

CPU clock : 400 MHz

Master clock : 133.333 MHz

DRAM: 128 MiB

WARNING: Caches not enabled

NAND: 256 MiB

MMC: mci: 0

*** Warning - bad CRC, using default environment

In: serial

Out: serial

Err: serial

Net: macb0

Warning: failed to set MAC address

Hit any key to stop autoboot: 0

NAND read: device 0 offset 0x200000, size 0x300000

Skipping bad block 0x00320000

3145728 bytes read: OK

## Booting kernel from Legacy Image at 22000000 ...

Image Name: Linux-2.6.39

Image Type: ARM Linux Kernel Image (uncompressed)

Data Size: 1979360 Bytes = 1.9 MiB

Load Address: 20008000

Entry Point: 20008000

Verifying Checksum ... OK

Loading Kernel Image ... OK

Starting kernel ...

Uncompressing Linux... done, booting the kernel.

Linux version 2.6.39 (root@zhangsz.zhangsz) (gcc version 4.4.1 (Sourcery G++ Lite 2010q1-202) ) #3 Mon Feb 15 16:32:15 CST 2016

CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=00053177

CPU: VIVT data cache, VIVT instruction cache

Machine: Atmel AT91SAM9X5-EK

Memory policy: ECC disabled, Data cache writeback

Clocks: CPU 400 MHz, master 133 MHz, main 12.000 MHz

Built 1 zonelists in Zone order, mobility grouping on. Total pages: 32512

Kernel command line: mem=128M console=ttyS0,115200 mtdparts=atmel_nand:8M(bootstrap/uboot/kernel)ro,-(rootfs) root=/dev/mtdblock1 rw rootfstype=ubifs ubi.mtd=1 root=ubi0:rootfs

PID hash table entries: 512 (order: -1, 2048 bytes)

Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)

Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)

Memory: 128MB = 128MB total

Memory: 125928k/125928k available, 5144k reserved, 0K highmem

Virtual kernel memory layout:

vector : 0xffff0000 - 0xffff1000 ( 4 kB)

fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)

DMA : 0xff000000 - 0xffe00000 ( 14 MB)

vmalloc : 0xc8800000 - 0xfee00000 ( 870 MB)

lowmem : 0xc0000000 - 0xc8000000 ( 128 MB)

modules : 0xbf000000 - 0xc0000000 ( 16 MB)

.init : 0xc0008000 - 0xc0028000 ( 128 kB)

.text : 0xc0028000 - 0xc03a515c (3573 kB)

.data : 0xc03a6000 - 0xc03cc8a0 ( 155 kB)

NR_IRQS:192

AT91: 128 gpio irqs in 4 banks

Console: colour dummy device 80x30

console [ttyS0] enabled

Calibrating delay loop... 199.06 BogoMIPS (lpj=995328)

pid_max: default: 32768 minimum: 301

Mount-cache hash table entries: 512

CPU: Testing write buffer coherency: ok

NET: Registered protocol family 16

AT91: CM rev B and higher

AT91: EK rev B and higher

AT91: Power Management (with slow clock mode)

AT91: Starting after power-restored wakeup

bio: create slab <bio-0> at 0

SCSI subsystem initialized

usbcore: registered new interface driver usbfs

usbcore: registered new interface driver hub

usbcore: registered new device driver usb

i2c-gpio i2c-gpio.0: using pins 62 (SDA) and 63 (SCL)

at_hdmac at_hdmac.0: Atmel AHB DMA Controller ( cpy slave ), 8 channels

at_hdmac at_hdmac.1: Atmel AHB DMA Controller ( cpy slave ), 8 channels

Switching to clocksource tcb_clksrc

NET: Registered protocol family 2

IP route cache hash table entries: 1024 (order: 0, 4096 bytes)

TCP established hash table entries: 4096 (order: 3, 32768 bytes)

TCP bind hash table entries: 4096 (order: 2, 16384 bytes)

TCP: Hash tables configured (established 4096 bind 4096)

TCP reno registered

UDP hash table entries: 256 (order: 0, 4096 bytes)

UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)

NET: Registered protocol family 1

RPC: Registered udp transport module.

RPC: Registered tcp transport module.

RPC: Registered tcp NFSv4.1 backchannel transport module.

NetWinder Floating Point Emulator V0.97 (double precision)

JFFS2 version 2.2. (NAND) (SUMMARY) 漏 2001-2006 Red Hat, Inc.

msgmni has been set to 245

io scheduler noop registered (default)

atmel_hlcdfb atmel_hlcdfb_base.0: 1500KiB frame buffer at 27a00000 (mapped at ffc00000)

atmel_hlcdfb atmel_hlcdfb_base.0: fb0: Atmel LCDC at 0xf8038000 (mapped at c8864000), irq 25

atmel_hlcdfb atmel_hlcdfb_ovl.0: 1500KiB frame buffer at 27000000 (mapped at ffa00000)

atmel_hlcdfb atmel_hlcdfb_ovl.0: fb1: Atmel LCDC at 0xf8038100 (mapped at c886c100), irq -6

atmel_usart.0: ttyS0 at MMIO 0xfffff200 (irq = 1) is a ATMEL_SERIAL

atmel_usart.1: ttyS1 at MMIO 0xf801c000 (irq = 5) is a ATMEL_SERIAL

brd: module loaded

loop: module loaded

ssc ssc.0: Atmel SSC device at 0xc8880000 (irq 28)

at24 0-0051: 65536 byte 24c512 EEPROM, writable, 128 bytes/write

atmel_nand atmel_nand: Using dma0chan0 for DMA transfers.

NAND device: Manufacturer ID: 0xec, Chip ID: 0xda (Samsung NAND 256MiB 3,3V 8-bit)

atmel_pmecc_init_params

Scanning device for bad blocks

Bad eraseblock 25 at 0x000000320000

Bad eraseblock 1339 at 0x00000a760000

Bad eraseblock 1759 at 0x00000dbe0000

2 cmdlinepart partitions found on MTD device atmel_nand

Creating 2 MTD partitions on "atmel_nand":

0x000000000000-0x000000800000 : "bootstrap/uboot/kernel"

0x000000800000-0x000010000000 : "rootfs"

UBI: attaching mtd1 to ubi0

UBI: physical eraseblock size: 131072 bytes (128 KiB)

UBI: logical eraseblock size: 126976 bytes

UBI: smallest flash I/O unit: 2048

UBI: VID header offset: 2048 (aligned 2048)

UBI: data offset: 4096

UBI: max. sequence number: 7

UBI: attached mtd1 to ubi0

UBI: MTD device name: "rootfs"

UBI: MTD device size: 248 MiB

UBI: number of good PEBs: 1982

UBI: number of bad PEBs: 2

UBI: number of corrupted PEBs: 0

UBI: max. allowed volumes: 128

UBI: wear-leveling threshold: 4096

UBI: number of internal volumes: 1

UBI: number of user volumes: 1

UBI: available PEBs: 0

UBI: total number of reserved PEBs: 1982

UBI: number of PEBs reserved for bad PEB handling: 19

UBI: max/mean erase counter: 2/0

UBI: image sequence number: 42708581

UBI: background thread "ubi_bgt0d" started, PID 355

CAN device driver interface

at91_can at91sam9x5_can.1: can0: Features changed: 0x00004804 -> 0x00004004

at91_can at91sam9x5_can.1: device registered (reg_base=c88e0000, irq=30)

macb macb.0: invalid hw address, using random

macb macb.0: eth0: Features changed: 0x00004800 -> 0x00004000

MACB_mii_bus: probed

eth0: Atmel MACB at 0xf802c000 irq 24 (f6:84:b3:06:57:65)

eth0: attached PHY driver [Generic PHY] (mii_bus:phy_addr=0:00, irq=-1)

ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver

atmel-ehci atmel-ehci: Atmel EHCI UHP HS

atmel-ehci atmel-ehci: new USB bus registered, assigned bus number 1

atmel-ehci atmel-ehci: irq 22, io mem 0x00700000

atmel-ehci atmel-ehci: USB 2.0 started, EHCI 1.00

hub 1-0:1.0: USB hub found

hub 1-0:1.0: 3 ports detected

ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver

at91_ohci at91_ohci: AT91 OHCI

at91_ohci at91_ohci: new USB bus registered, assigned bus number 2

at91_ohci at91_ohci: irq 22, io mem 0x00600000

hub 2-0:1.0: USB hub found

hub 2-0:1.0: 3 ports detected

Initializing USB Mass Storage driver...

usbcore: registered new interface driver usb-storage

USB Mass Storage support registered.

usbcore: registered new interface driver libusual

atmel_usba_udc atmel_usba_udc: MMIO registers at 0xf803c000 mapped at c88ee000

atmel_usba_udc atmel_usba_udc: FIFO at 0x00500000 mapped at c8900000

input: gpio-keys as /devices/platform/gpio-keys/input/input0

atmel_tsadcc atmel_tsadcc: Master clock is set at: 133333333 Hz

atmel_tsadcc atmel_tsadcc: Prescaler is set at: 32

input: atmel touch screen controller as /devices/platform/atmel_tsadcc/input/input1

at91_rtc at91_rtc: rtc core: registered at91_rtc as rtc0

AT91 Real Time Clock driver.

i2c /dev entries driver

usbcore: registered new interface driver usbhid

usbhid: USB HID core driver

nf_conntrack version 0.5.0 (1967 buckets, 7868 max)

ip_tables: (C) 2000-2006 Netfilter Core Team

TCP cubic registered

NET: Registered protocol family 17

can: controller area network core (rev 20090105 abi 8)

NET: Registered protocol family 29

can: raw protocol (rev 20090105)

Registering the dns_resolver key type

at91_rtc at91_rtc: setting system clock to 2007-01-01 00:00:11 UTC (1167609611)

atmel_mci atmel_mci.0: Using dma0chan1 for DMA transfers

atmel_mci atmel_mci.0: Atmel MCI controller at 0xf0008000 irq 12, 1 slots

UBIFS: recovery needed

UBIFS: recovery completed

UBIFS: mounted UBI device 0, volume 0, name "rootfs"

UBIFS: file system size: 236302336 bytes (230764 KiB, 225 MiB, 1861 LEBs)

UBIFS: journal size: 9023488 bytes (8812 KiB, 8 MiB, 72 LEBs)

UBIFS: media format: w4/r0 (latest is w4/r0)

UBIFS: default compressor: lzo

UBIFS: reserved for root: 0 bytes (0 KiB)

VFS: Mounted root (ubifs filesystem) on device 0:12.

Freeing init memory: 128K

#-----Start /etc/init.d/rcS

***********************************************

Start Linux

2016 02 15

AT91SAM9X35ek

***********************************************

Please press Enter to activate this console. / #

/ # ls

bin dev home linuxrc proc sbin tmp var

boot etc lib mnt root sys usr

/ # cd home/

/home # ls

hello.txt

/home # cat hello.txt

保存的内容不能保存下来吗？重新启动呢？

/home #

接下来，我想，还需要不断的总结与实践，不断的完善整个流程。更进一步的学习Linux驱动，用户程序的运行，网络的应用，人机界面等等。

有时候，一个小小的问题或是失误，就会让你灰心，让你找借口，但是，只要你不断的尝试，不断的把资料归类，不断的理清其中的正确的思路，你就会不断的向前。大胆实践，大胆的尝试，才能收获好的结果。能移植Linux我觉得只是进入Linux的第一步，还需要不断的修改与裁减内核，优化启动时间，加入用户程序，等等，才能实现自己想要的东西。

大胆的尝试与动手实践，值得！