I.MX6Q(TQIMX6Q/TQE9)学习笔记——内核启动与文件系统挂载

经过前面的移植，u-boot已经有能力启动内核了，本文主要来看下如何通过之前移植的u-boot来启动内核。如果按照前面的文章完成了LTIB 的编译，那么，Linux的内核应该就会出现rpm/BUILD/目录下，接下来，我们就开始移植这个3.0.35版本的内核到TQIMX6Q。

内核的编译

为了简化内核编译的过程，可以在内核目录下创建编译脚本，命名为build.sh，内容如下：

#!/bin/sh
export ARCH=arm
export CROSS_COMPILE=/opt/freescale/usr/local/gcc-4.6.2-glibc-2.13-linaro-multilib-2011.12/fsl-linaro-toolchain/bin/arm-none-linux-gnueabi-
make uImage -j8

为该脚本添加可执行权限：

chmod a+x build.sh

由于本文使用的内核镜像格式是uImage，因此会依赖u-boot编译时生成的工具——mkimage。该工具为u-boot目录的tools子目录下，可以将mkimage拷贝到/usr/bin或者/usr/local/bin目录下，当然也可以是用环境变量PATH，方法如下：

export PATH=$PATH:~/Projects/imx6/L3.0.35_4.1.0/ltib/rpm/BUILD/u-boot-2009.8/tools

安装路径需要根据自己的实际情况填写。完成以上操作之后就可以编译内核了，执行脚本程序：

./build.sh

内核的编译时间较长，需耐心等待，也与机器的配置有关。

内核启动尝试

内核编译完成后，uImage会出现在arch/arm/boot/目录下，将该镜像烧写到SD卡：

sudo dd if=arch/arm/boot/uImage of=/dev/sdb bs=512 seek=2048
sync

然后用SD卡启动开发板，按任意键打断u-boot启动，进入命令行，修改u-boot环境变量：

setenv bootargs_base 'setenv bootargs console=ttymxc0,115200'
setenv bootargs_mmc 'setenv bootargs ${bootargs} root=/dev/mmcblk1p1 rootwait rw'
setenv bootcmd_mmc 'run bootargs_base bootargs_mmc; mmc dev 1; mmc read ${loadaddr} 0x800 0x2000; bootm'
setenv bootcmd 'run bootcmd_mmc'
saveenv

以上指令的含义：

第一条：bootargs_base，维持默认状态，作用是在bootargs中指定串口终端及波特率。
第二条：bootargs_mmc，是MMC方式启动内核使用的bootargs特有参数。
第三条：bootcmd_mmc，是MMC方式启动特有的命令组合。
第四条：bootcmd是内核启动命令。
第五条：保存env到SD存储介质。

完成之后执行命令：

boot

或者重新上电开发板就可以启动内核了。

内核的修改

通过上面的设置，u-boot已经可以引导内核启动了，但是，内核启动后仅打印了一部分log，猜测是内核中UART的GPIO管脚配置不正确，开
始一段log能打印出来是因为u-boot阶段配置好了UART，而内核中又将这两个引脚配置为其它用途了。首先来解决串口log问题，打开文件
arch/arm/mach-mx6/board-mx6q_sabresd.h并作如下修改：

... ...
/* UART1 for debug */
// MX6Q_PAD_CSI0_DAT10__UART1_TXD,
MX6Q_PAD_SD3_DAT7__UART1_TXD,
// MX6Q_PAD_CSI0_DAT11__UART1_RXD,
MX6Q_PAD_SD3_DAT6__UART1_RXD,
... ...

其实，u-boot已经作过相应的修改，修改UART1相关的配置信息，除了以上修改之外，还需要将SD3与串口冲突的两个引脚：

/* USDHC3 */
MX6Q_PAD_SD3_CLK__USDHC3_CLK_50MHZ,
MX6Q_PAD_SD3_CMD__USDHC3_CMD_50MHZ,
MX6Q_PAD_SD3_DAT0__USDHC3_DAT0_50MHZ,
MX6Q_PAD_SD3_DAT1__USDHC3_DAT1_50MHZ,
MX6Q_PAD_SD3_DAT2__USDHC3_DAT2_50MHZ,
MX6Q_PAD_SD3_DAT3__USDHC3_DAT3_50MHZ,
// MX6Q_PAD_SD3_DAT4__USDHC3_DAT4_50MHZ,
// MX6Q_PAD_SD3_DAT5__USDHC3_DAT5_50MHZ,
// MX6Q_PAD_SD3_DAT6__USDHC3_DAT6_50MHZ,
// MX6Q_PAD_SD3_DAT7__USDHC3_DAT7_50MHZ,
MX6Q_PAD_NANDF_D0__GPIO_2_0, /* SD3_CD */
MX6Q_PAD_NANDF_D1__GPIO_2_1, /* SD3_WP */

注释掉以上四行。保存后重新编译内核并烧写到SD卡，重新启动开发板会发现内核已经可以正常打印启动Log了。接下来将LTIB编译生成的rootfs烧写到开发板，并使用编译好的内核挂载该文件系统。

挂载文件系统

文件系统的构建方式都差不多，这里就不再自己构建了，直接使用LTIB编译时生成的文件系统。

将SD卡插ubunut上，对该SD卡进行分区：

sudo fdisk /dev/sdb

然后如下操作：

Step1: 通过指令u切换到sectors模式。输入u后回车，fdisk会在sectors模式和cylinders模式间切换，这里切换到sectors模式。

Step2:通过d指令删除原来的分区。重复的输入d并回车，可以删除SD卡原有的分区，知道没有任何分区为止。

Step3:通过n指令新建分区。输入n并回车。

Step4:输入分区编号。这里输入数字1。

Step5:输入分区的起始位置。该位置是sectors为单位的，每个sector的大小为512B，这里偏移8M，给内核留下足够的存储空间，输入16384并回车。

Step6:输入分区的结束为止。直接使用默认值，即到达SD卡的末尾，故直接回车即可。

Step7:保存分区信息。输入指令w并回车。

这样就完成了SD卡的分区，接下来需要将该分区格式化为ext3或者ext4，指令如下：

sudo mkfs.ext3 /dev/sdb1
或者
sudo mkfs.ext4 /dev/sdb1

最后，将文件系统拷贝到该分区，进入ltib目录下的rootfs文件夹，然后执行如下指令：

sudo mount /dev/sdb1 /mnt
sudo cp -a * /mnt

也可以重新拔插SD卡，将rootfs内的文件拷贝到ubunut挂载的分区。

如果rootfs是压缩包，则可以解压到SD卡分区，比如bzip的压缩包，可以如下处理：

sudo tar jxf rootfs.tar.bz2 -C /mnt
sudo mv /mnt/rootfs/* /mnt

不
过一般不用这么麻烦，直接用前面的方式拷贝即可。拷贝完成后执行sync指令，然后将SD插到开发板上启动开发板。启动时发现内核并没有成功挂载上
rootfs文件系统，且根本没有识别到SD卡，因此，猜测是SD相关的引脚配置不正确。通过查阅原理图及内核源码文件可知，代码中配置的uSDHC2的
WP和CD引脚与TQIMX6Q的连接方式不一致，因此，需要作如下修改：

Step1：打开arch/arm/mach-mx6/board-mx6q_sabresd.h，作如下修改：

/* USDHC2 */
MX6Q_PAD_SD2_CLK__USDHC2_CLK,
MX6Q_PAD_SD2_CMD__USDHC2_CMD,
MX6Q_PAD_SD2_DAT0__USDHC2_DAT0,
MX6Q_PAD_SD2_DAT1__USDHC2_DAT1,
MX6Q_PAD_SD2_DAT2__USDHC2_DAT2,
MX6Q_PAD_SD2_DAT3__USDHC2_DAT3,
// MX6Q_PAD_NANDF_D4__USDHC2_DAT4,
// MX6Q_PAD_NANDF_D5__USDHC2_DAT5,
// MX6Q_PAD_NANDF_D6__USDHC2_DAT6,
// MX6Q_PAD_NANDF_D7__USDHC2_DAT7,
// MX6Q_PAD_NANDF_D2__GPIO_2_2, /* SD2_CD */
MX6Q_PAD_GPIO_2__USDHC2_WP,
// MX6Q_PAD_NANDF_D3__GPIO_2_3, /* SD2_WP */
MX6Q_PAD_GPIO_4__USDHC2_CD,

Step2：打开arch/arm/mach-mx6/board-mx6q_sabresd.c，作如下修改：

#define SABRESD_SD2_CD IMX_GPIO_NR(1, 4)
#define SABRESD_SD2_WP IMX_GPIO_NR(1, 2)

即将SD2_CD的引脚号修改为GPIO1_4和GPIO1_2。

按照以上步骤修改内核后重新编译并烧写到SD卡，然后使用SD卡启动开发板。

效果展示

按照上面的步骤修改后内核就可以正常启动了，下面是启动Log：

U-Boot 2009.08-dirty ( 3月 23 2015 - 23:14:02)
CPU: Freescale i.MX6 family TO1.2 at 792 MHz
Thermal sensor with ratio = 174
Temperature: 23 C, calibration data 0x54e4bb69
mx6q pll1: 792MHz
mx6q pll2: 528MHz
mx6q pll3: 480MHz
mx6q pll8: 50MHz
ipg clock : 66000000Hz
ipg per clock : 66000000Hz
uart clock : 80000000Hz
cspi clock : 60000000Hz
ahb clock : 132000000Hz
axi clock : 264000000Hz
emi_slow clock: 132000000Hz
ddr clock : 528000000Hz
usdhc1 clock : 198000000Hz
usdhc2 clock : 198000000Hz
usdhc3 clock : 198000000Hz
usdhc4 clock : 198000000Hz
nfc clock : 24000000Hz
Board: i.MX6Q-SABRESD: unknown-board Board: 0x63012 [POR ]
Boot Device: SD
I2C: ready
DRAM: 1 GB
MMC: FSL_USDHC: 0,FSL_USDHC: 1,FSL_USDHC: 2,FSL_USDHC: 3
In: serial
Out: serial
Err: serial
Net: got MAC address from IIM: 00:00:00:00:00:00
FEC0 [PRIME]
Hit any key to stop autoboot: 0
mmc1 is current device
MMC read: dev # 1, block # 2048, count 8192 ... 8192 blocks read: OK
## Booting kernel from Legacy Image at 10800000 ...
Image Name: Linux-3.0.35-2666-gbdde708-g3344
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 3866004 Bytes = 3.7 MB
Load Address: 10008000
Entry Point: 10008000
Verifying Checksum ... OK
Loading Kernel Image ... OK
OK
Starting kernel ...
Uncompressing Linux... done, booting the kernel.
Linux version 3.0.35-2666-gbdde708-g334422e-dirty (lilianrong@ubuntu) (gcc version 4.6.2 20110630 (prerelease) (Freescale MAD -- Linaro 2011.07 -- Built at 2011/08/10 09:20) ) #5 SMP PREEMPT Wed Mar 25 19:29:24 CST 2015
CPU: ARMv7 Processor [412fc09a] revision 10 (ARMv7), cr=10c53c7d
CPU: VIPT nonaliasing data cache, VIPT aliasing instruction cache
Machine: Freescale i.MX 6Quad/DualLite/Solo Sabre-SD Board
Ignoring unrecognised tag 0x54410008
Memory policy: ECC disabled, Data cache writealloc
CPU identified as i.MX6Q, silicon rev 1.2
PERCPU: Embedded 7 pages/cpu @8c008000 s5440 r8192 d15040 u32768
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 194560
Kernel command line: console=ttymxc0,115200 root=/dev/mmcblk1p1 rootwait rw
PID hash table entries: 4096 (order: 2, 16384 bytes)
Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
Memory: 512MB 256MB = 768MB total
Memory: 765764k/765764k available, 282812k reserved, 0K highmem
Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
DMA : 0xf4600000 - 0xffe00000 ( 184 MB)
vmalloc : 0xc0800000 - 0xf2000000 ( 792 MB)
lowmem : 0x80000000 - 0xc0000000 (1024 MB)
pkmap : 0x7fe00000 - 0x80000000 ( 2 MB)
modules : 0x7f000000 - 0x7fe00000 ( 14 MB)
.init : 0x80008000 - 0x8003c000 ( 208 kB)
.text : 0x8003c000 - 0x80a8f8f4 (10575 kB)
.data : 0x80a90000 - 0x80af3e00 ( 400 kB)
.bss : 0x80af3e24 - 0x80b41d4c ( 312 kB)
SLUB: Genslabs=13, HWalign=32, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
Preemptible hierarchical RCU implementation.
NR_IRQS:624
MXC GPIO hardware
sched_clock: 32 bits at 3000kHz, resolution 333ns, wraps every 1431655ms
arm_max_freq=1GHz
MXC_Early serial console at MMIO 0x2020000 (options '115200')
bootconsole [ttymxc0] enabled
Console: colour dummy device 80x30
Calibrating delay loop... 1581.05 BogoMIPS (lpj=7905280)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
hw perfevents: enabled with ARMv7 Cortex-A9 PMU driver, 7 counters available
CPU1: Booted secondary processor
CPU2: Booted secondary processor
CPU3: Booted secondary processor
Brought up 4 CPUs
SMP: Total of 4 processors activated (6324.22 BogoMIPS).
print_constraints: dummy:
NET: Registered protocol family 16
print_constraints: vddpu: 725 <--> 1300 mV at 700 mV fast normal
print_constraints: vddcore: 725 <--> 1300 mV at 1150 mV fast normal
print_constraints: vddsoc: 725 <--> 1300 mV at 1200 mV fast normal
print_constraints: vdd2p5: 2000 <--> 2775 mV at 2400 mV fast normal
print_constraints: vdd1p1: 800 <--> 1400 mV at 1100 mV fast normal
print_constraints: vdd3p0: 2625 <--> 3400 mV at 3000 mV fast normal
hw-breakpoint: found 6 breakpoint and 1 watchpoint registers.
hw-breakpoint: 1 breakpoint(s) reserved for watchpoint single-step.
hw-breakpoint: maximum watchpoint size is 4 bytes.
L310 cache controller enabled
l2x0: 16 ways, CACHE_ID 0x410000c7, AUX_CTRL 0x02070000, Cache size: 1048576 B
bio: create slab <bio-0> at 0
mxs-dma mxs-dma-apbh: initialized
print_constraints: SPKVDD: 4200 mV
print_constraints: vmmc: 3300 mV
SCSI subsystem initialized
spi_imx imx6q-ecspi.0: probed
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
Freescale USB OTG Driver loaded, $Revision: 1.55 $
mc_pfuze 1-0008: recv failed!:-5,80
mc_pfuze: probe of 1-0008 failed with error -1
imx-ipuv3 imx-ipuv3.0: IPU DMFC NORMAL mode: 1(0~1), 5B(4,5), 5F(6,7)
imx-ipuv3 imx-ipuv3.1: IPU DMFC NORMAL mode: 1(0~1), 5B(4,5), 5F(6,7)
mxc_mipi_csi2 mxc_mipi_csi2: i.MX MIPI CSI2 driver probed
mxc_mipi_csi2 mxc_mipi_csi2: i.MX MIPI CSI2 dphy version is 0x3130302a
MIPI CSI2 driver module loaded
Advanced Linux Sound Architecture Driver Version 1.0.24.
Bluetooth: Core ver 2.16
NET: Registered protocol family 31
Bluetooth: HCI device and connection manager initialized
Bluetooth: HCI socket layer initialized
Bluetooth: L2CAP socket layer initialized
Bluetooth: SCO socket layer initialized
cfg80211: Calling CRDA to update world regulatory domain
max17135 2-0048: PMIC MAX17135 for eInk display
i2c-core: driver [max17135] using legacy suspend method
i2c-core: driver [max17135] using legacy resume method
Switching to clocksource mxc_timer1
NET: Registered protocol family 2
IP route cache hash table entries: 32768 (order: 5, 131072 bytes)
TCP established hash table entries: 131072 (order: 8, 1048576 bytes)
TCP bind hash table entries: 65536 (order: 7, 786432 bytes)
TCP: Hash tables configured (established 131072 bind 65536)
TCP reno registered
UDP hash table entries: 512 (order: 2, 16384 bytes)
UDP-Lite hash table entries: 512 (order: 2, 16384 bytes)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
PMU: registered new PMU device of type 0
Static Power Management for Freescale i.MX6
wait mode is enabled for i.MX6
cpaddr = c0880000 suspend_iram_base=c091c000
PM driver module loaded
IMX usb wakeup probe
add wake up source irq 75
IMX usb wakeup probe
cpu regulator mode:ldo_enable
i.MXC CPU frequency driver
msgmni has been set to 1495
alg: No test for stdrng (krng)
io scheduler noop registered
io scheduler deadline registered
io scheduler cfq registered (default)
mxc_mipi_dsi mxc_mipi_dsi: i.MX MIPI DSI driver probed
MIPI DSI driver module loaded
mxc_sdc_fb mxc_sdc_fb.0: register mxc display driver ldb
_regulator_get: get() with no identifier
imx-ipuv3 imx-ipuv3.1: IPU DMFC DP HIGH RESOLUTION: 1(0,1), 5B(2~5), 5F(6,7)
Console: switching to colour frame buffer device 128x48
mxc_sdc_fb mxc_sdc_fb.1: register mxc display driver ldb
mxc_sdc_fb mxc_sdc_fb.2: register mxc display driver lcd
mxc_sdc_fb mxc_sdc_fb.3: register mxc display driver ldb
mxc_sdc_fb mxc_sdc_fb.3: ipu1-di0 already in use
mxc_sdc_fb: probe of mxc_sdc_fb.3 failed with error -16
imx-sdma imx-sdma: loaded firmware 1.1
imx-sdma imx-sdma: initialized
Serial: IMX driver
imx-uart.2: ttymxc2 at MMIO 0x21ec000 (irq = 60) is a IMX
imx-uart.0: ttymxc0 at MMIO 0x2020000 (irq = 58) is a IMX
console [ttymxc0] enabled, bootconsole disabled
console [ttymxc0] enabled, bootconsole disabled
loop: module loaded
No sata disk.
m25p80 spi0.0: unrecognized JEDEC id ffffff
GPMI NAND driver registered. (IMX)
vcan: Virtual CAN interface driver
CAN device driver interface
flexcan netdevice driver
FEC Ethernet Driver
fec_enet_mii_bus: probed
ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
fsl-ehci fsl-ehci.0: Freescale On-Chip EHCI Host Controller
fsl-ehci fsl-ehci.0: new USB bus registered, assigned bus number 1
fsl-ehci fsl-ehci.0: irq 75, io base 0x02184000
fsl-ehci fsl-ehci.0: USB 2.0 started, EHCI 1.00
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 1 port detected
add wake up source irq 72
fsl-ehci fsl-ehci.1: Freescale On-Chip EHCI Host Controller
fsl-ehci fsl-ehci.1: new USB bus registered, assigned bus number 2
fsl-ehci fsl-ehci.1: irq 72, io base 0x02184200
fsl-ehci fsl-ehci.1: USB 2.0 started, EHCI 1.00
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 1 port detected
Initializing USB Mass Storage driver...
usbcore: registered new interface driver usb-storage
USB Mass Storage support registered.
ARC USBOTG Device Controller driver (1 August 2005)
mousedev: PS/2 mouse device common for all mice
input: gpio-keys as /devices/platform/gpio-keys/input/input0
input: max11801_ts as /devices/platform/imx-i2c.1/i2c-1/1-0048/input/input1
egalax_ts 1-0004: egalax_ts: failed to read firmware version
egalax_ts: probe of 1-0004 failed with error -5
egalax_ts 2-0004: egalax_ts: failed to read firmware version
egalax_ts: probe of 2-0004 failed with error -5
elan - Read Hello Packet Failed
elan-touch: probe of 2-0010 failed with error -22
i2c-core: driver [isl29023] using legacy suspend method
i2c-core: driver [isl29023] using legacy resume method
snvs_rtc snvs_rtc.0: rtc core: registered snvs_rtc as rtc0
i2c /dev entries driver
Linux video capture interface: v2.00
mxc_v4l2_output mxc_v4l2_output.0: V4L2 device registered as video16
mxc_v4l2_output mxc_v4l2_output.0: V4L2 device registered as video17
mxc_v4l2_output mxc_v4l2_output.0: V4L2 device registered as video18
mxc_v4l2_output mxc_v4l2_output.0: V4L2 device registered as video19
mxc_v4l2_output mxc_v4l2_output.0: V4L2 device registered as video20
mag3110 2-000e: check mag3110 chip ID
mag3110 2-000e: read chip ID 0xfffffffb is not equal to 0xc4!
mag3110: probe of 2-000e failed with error -22
i2c-core: driver [mag3110] using legacy suspend method
i2c-core: driver [mag3110] using legacy resume method
mma8451 0-001c: read chip ID 0x1 is not equal to 0x1a or 0x2a!
mma8451: probe of 0-001c failed with error -22
imx2-wdt imx2-wdt.0: IMX2+ Watchdog Timer enabled. timeout=60s (nowayout=1)
Bluetooth: Virtual HCI driver ver 1.3
Bluetooth: HCI UART driver ver 2.2
Bluetooth: HCIATH3K protocol initialized
Bluetooth: Generic Bluetooth USB driver ver 0.6
usbcore: registered new interface driver btusb
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
mmc0: SDHCI controller on platform [sdhci-esdhc-imx.3] using DMA
sdhci sdhci-esdhc-imx.1: no card-detect pin available!
mmc1: SDHCI controller on platform [sdhci-esdhc-imx.1] using DMA
mmc2: SDHCI controller on platform [sdhci-esdhc-imx.2] using DMA
mxc_vdoa mxc_vdoa: i.MX Video Data Order Adapter(VDOA) driver probed
VPU initialized
mxc_asrc registered
Galcore version 4.6.9.6622
Thermal calibration data is 0x54e4bb69
Thermal sensor with ratio = 174
Anatop Thermal registered as thermal_zone0
anatop_thermal_probe: default cooling device is cpufreq!
leds-gpio: probe of leds-gpio failed with error -16
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
usbcore: registered new interface driver snd-usb-audio
mxc_hdmi_soc mxc_hdmi_soc.0: MXC HDMI Audio
Cirrus Logic CS42888 ALSA SoC Codec Driver
i2c-core: driver [cs42888] using legacy suspend method
i2c-core: driver [cs42888] using legacy resume method
imx-hdmi-soc-dai imx-hdmi-soc-dai.0: Failed: Load HDMI-video first.
wm8962 0-001a: Failed to get supply 'DCVDD': -19
wm8962 0-001a: Failed to request supplies: -19
wm8962 0-001a: asoc: failed to probe CODEC wm8962.0-001a: -19
asoc: failed to instantiate card wm8962-audio: -19
mmc0: new high speed DDR MMC card at address 0001
mmcblk0: mmc0:0001 008G92 7.28 GiB
mmcblk0boot0: mmc0:0001 008G92 partition 1 4.00 MiB
mmcblk0boot1: mmc0:0001 008G92 partition 2 4.00 MiB
mmcblk0: p1 p2 p3 < p5 p6 p7 p8 > p4
imx_3stack asoc driver
mmcblk0boot1: unknown partition table
Initialize HDMI-audio failed. Load HDMI-video first!
ALSA device list:
No soundcards found.
NET: Registered protocol family 26
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)
can: broadcast manager protocol (rev 20090105 t)
Bluetooth: RFCOMM TTY layer initialized
Bluetooth: RFCOMM socket layer initialized
Bluetooth: RFCOMM ver 1.11
Bluetooth: BNEP (Ethernet Emulation) ver 1.3
Bluetooth: BNEP filters: protocol multicast
Bluetooth: HIDP (Human Interface Emulation) ver 1.2
lib80211: common routines for IEEE802.11 drivers
VFP support v0.3:
implementor 41 architecture 3 part 30 variant 9 rev 4
mmcblk0boot0: unknown partition table
Bus freq driver module loaded
Bus freq driver Enabled
mxc_dvfs_core_probe
DVFS driver module loaded
regulator_init_complete: SPKVDD: incomplete constraints, leaving on
snvs_rtc snvs_rtc.0: setting system clock to 1970-01-01 00:46:38 UTC (2798)
Waiting for root device /dev/mmcblk1p1...
mmc1: new high speed SDHC card at address e624
mmcblk1: mmc1:e624 SS08G 7.40 GiB
mmcblk1: p1
EXT3-fs: barriers not enabled
kjournald starting. Commit interval 5 seconds
EXT3-fs (mmcblk1p1): using internal journal
EXT3-fs (mmcblk1p1): recovery complete
EXT3-fs (mmcblk1p1): mounted filesystem with writeback data mode
VFS: Mounted root (ext3 filesystem) on device 179:25.
Freeing init memory: 208K
starting pid 1401, tty '': '/etc/rc.d/rcS'
Mounting /proc and /sys
Starting the hotplug events dispatcher udevd
udevd (1410): /proc/1410/oom_adj is deprecated, please use /proc/1410/oom_score_adj instead.
Synthesizing initial hotplug events
Setting the hostname to freescale
Mounting filesystems
cp: write error: No space left on device
cp: write error: No space left on device
cp: write error: No space left on device
cp: write error: No space left on device
cp: write error: No space left on device
cp: write error: No space left on device
mount: mounting usbfs on /proc/bus/usb failed: No such file or directory
starting pid 3114, tty '': '/etc/rc.d/rc_gpu.S'
starting pid 3120, tty '': '/etc/rc.d/rc_mxc.S'
arm-none-linux-gnueabi-gcc (Freescale MAD -- Linaro 2011.07 -- Built at 2011/08/10 09:20) 4.6.2 20110630 (prerelease)
root filesystem built on Sun, 15 Mar 2015 14:27:16 +0800
Freescale Semiconductor, Inc.
freescale login: root
login[3122]: root login on 'ttymxc0'
root@freescale ~$
root@freescale ~$ cd /
root@freescale /$ ls
bin etc lost+found proc share unit_tests
boot home mnt root sys usr
dev lib opt sbin tmp var
root@freescale /$

总结

基于Freescale官方维护的内核进行移植有非常详细的文档可以参考，而且还可以参考天嵌移植的代码，学习起来比较轻松，业余时间搞搞还是很不错的。以上有什么问题可以留言讨论。
http://blog.****.net/girlkoo/article/details/44626011