基于tiny4412的Linux内核移植（支持device tree）（二）

转自：http://www.cnblogs.com/pengdonglin137/p/5143516.html

阅读目录(Content)

• 作者信息
• 平台简介
• 步骤

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作者信息

作者: 彭东林

邮箱：[e-mail]

QQ：405728433

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平台简介

开发板：tiny4412ADK + S700 + 4GB Flash

要移植的内核版本：Linux-4.4.0 （支持device tree）

u-boot版本：友善之臂自带的 U-Boot 2010.12 （为支持uImage启动，做了少许改动）

busybox版本：busybox 1.25

交叉编译工具链： arm-none-linux-gnueabi-gcc

      （gcc version 4.8.3 20140320 (prerelease) (Sourcery CodeBench Lite 2014.05-29)）

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步骤

继续上文。

由于Linux-4.4.0对tiny4412已经有了很好的支持，所以留给我们的工作就很少了。

一、修改arch/arm/boot/dts/exynos4412-tiny4412.dts

diff --git a/arch/arm/boot/dts/exynos4412-tiny4412.dts b/arch/arm/boot/dts/exynos4412-tiny4412.dts

index 4840bbd..aeca42a 100644

--- a/arch/arm/boot/dts/exynos4412-tiny4412.dts

+++ b/arch/arm/boot/dts/exynos4412-tiny4412.dts

@@ -21,6 +21,7 @@

        chosen {

                stdout-path = &;serial_0;

+               bootargs = "root=/dev/ram0 rw rootfstype=ext4 console=ttySAC0,115200 init=/linuxrc earlyprintk";

        };

        memory {

@@ -78,7 +79,7 @@

        bus-width = <;4>;

        pinctrl-0 = <;&sd2_clk &sd2_cmd &sd2_cd &sd2_bus4>;

        pinctrl-names = "default";

-       status = "okay";

+       status = "disabled";

 };

 &;serial_0 {

这里关键的一点是在chosen中增加了bootargs的设置，上面设置bootargs表示的意思是：根文件系统是ramdisk，可读写，文件系统类型是ext4格式，串口终端使用ttySAC0，波特率是115200，earlyprintk用于打印内核启动早期的一些log，它会把printk的信息打印到一个叫做bootconsole的终端上，在真正的console注册后，bootconsole会被disable掉，要想使用earlyprintk，需要在内核中做相关的配置，这个下面再说。bootargs的设置很灵活，既可以在内核的设备树中设置，也可以在u-boot中设置，需要注意的是：如果在u-boot中设置了bootargs的话，在bootm的时候u-boot会用自己的bootargs来覆盖设备树里的bootargs( do_bootm_linux -> bootm_linux_fdt -> fdt_chosen)。还有一点是把SD卡控制器2给禁掉了，目前SD控制器的初始化还有些问题，会导致内核挂掉，这个以后再解决，因为我们将来先用ramdisk做根文件系统，跟eMMC和SD卡都没有关系。

二、制作ramdisk根文件系统

1、制作ramdisk，首先需要下载busybox的代码，可以从https://busybox.net/downloads/下载，然后编译出根文件系统，具体过程我这里就不写了，网上有很多这方面的资料。我已经制作好了一个可用了文件系统，可以从下面的地址处下载：

http://files.cnblogs.com/files/pengdonglin137/rootfs.tar.gz

下载完成后，解压缩，开始制作ramdisk，制作的过程我写了一个脚本 mk_ramdisk.sh

#!/bin/bash

rm -rf ramdisk*

sudo dd if=/dev/zero of=ramdisk bs=1k count=8192

sudo mkfs.ext4 -F ramdisk

sudo mkdir -p ./initrd

sudo mount -t ext4 ramdisk ./initrd

sudo cp rootfs/* ./initrd -raf

sudo mknod initrd/dev/console c 5 1

sudo mknod initrd/dev/null c 1 3

sudo umount ./initrd

sudo gzip --best -c ramdisk >; ramdisk.gz

sudo mkimage -n "ramdisk" -A arm -O linux -T ramdisk -C gzip -d ramdisk.gz ramdisk.img

最后生成的ramdisk.img就是我们需要的，在上面的脚本中生成的ramdisk镜像也可以作为ramdisk使用，用法下面再说。

下面的链接是一个已经制作好的ramdisk镜像，解压后即可使用：

http://files.cnblogs.com/files/pengdonglin137/ramdisk.zip

2、配置内核，支持ramdisk

make menuconfig

File systems --->;

    <*> Second extended fs support

Device Drivers

    SCSI device support --->;

        <*> SCSI disk support

    Block devices --->;

        <*>RAM block device support

        (16)Default number of RAM disks

        (8192) Default RAM disk size (kbytes) (修改为8M)

General setup --->;

    [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support

这个exynos的默认配置就已经支持了。

3、配置内核，使其支持tmpfs

$ make menuconfig

File systems --->;

    Pseudo filesystems --->

        [*] Virtual memory file system support (former shm fs)

        [*] Tmpfs POSIX Access Control Lists

这个exynos的默认配置也已经支持了。

三、编译内核

1、首先要设置使用的交叉编译工具链

diff --git a/Makefile b/Makefile

index 70dea02..5d96411 100644

--- a/Makefile

+++ b/Makefile

@@ -248,8 +248,8 @@ SUBARCH := $(shell uname -m | sed -e s/i.86/x86/ -e s/x86_64/x86/ \

 # "make" in the configured kernel build directory always uses that.

 # Default value for CROSS_COMPILE is not to prefix executables

 # Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile

-ARCH           ?= $(SUBARCH)

-CROSS_COMPILE  ?= $(CONFIG_CROSS_COMPILE:"%"=%)

+ARCH           ?= arm

+CROSS_COMPILE  ?= /root/tiny4412_android5/SysPort/cross_compile/arm-2014.05/bin/arm-none-linux-gnueabi-

2、编译

make exynos_defconfig

make uImage LOADADDR=0x40008000 -j2

生成的uImage在arch/arm/boot下。 

四、编译设备树

make dtbs

然后在 arch/arm/boot/dts/会生成tiny4412上用的设备树镜像文件exynos4412-tiny4412.dtb。

五、测试

由于tiny4412的u-boot目前还不支持usb网卡，只能使用dnw来下载，并且tiny4412的u-boot中已经自带了dnw命令了。开发机上运行的dnw的代码可以到下面的链接下载：

http://files.cnblogs.com/files/pengdonglin137/dnw.tar.gz

下载完成后解压，在压缩包里已经有一个编译好的dnw可执行程序。也可执行make，会自动编译生成一个dnw可执行程序，要编译的话，机器上要安装usb相关的库，安装命令如下：

sudo  apt-get install libusb-dev

有了dnw，下面开始测试。

• 启动开发板，进入u-boot命令模式；
• 下载uImage

在u-boot里执行下载uImage的命令: dnw 0x40600000   (这个地址不唯一)

在开发机中执行：dnw arch/arm/boot/uImage

• 下载ramdisk

在u-boot里执行下载uImage的命令: dnw 0x41000000   (这个地址不唯一)

在开发机中执行：dnw ramdisk.img

• 下载设备树镜像

在u-boot里执行下载uImage的命令: dnw 0x42000000   (这个地址不唯一)

在开发机中执行：dnw arch/arm/boot/dts/exynos4412-tiny4412.dtb

• 启动内核

使用bootm启动内核：bootm 0x40600000 0x41000000 0x42000000

 

下面是完整的启动log：

U-Boot 2010.12-00000-gb391276-dirty (Jan 17 2016 - 06:03:22) for TINY4412CPU:    S5PC220 [Samsung SOC on SMP Platform Base on ARM CortexA9]        APLL = 1400MHz, MPLL = 800MHzBoard:  TINY4412DRAM:   1023 MiBvdd_arm: 1.2vdd_int: 1.0vdd_mif: 1.1BL1 version:  N/A (TrustZone Enabled BSP)Checking Boot Mode ... SDMMCREVISION: 1.1MMC Device 0: 3803 MBMMC Device 1: 3728 MBMMC Device 2: N/A*** Warning - using default environmentNet:    No ethernet found.Hit any key to stop autoboot:  0 TINY4412 # dnw 0x41000000OTG cable Connected!Now, Waiting for DNW to transmit dataDownload Done!! Download Address: 0x41000000, Download Filesize:0x27752eChecksum is being calculated...Checksum O.K.TINY4412 # dnw 0x42000000OTG cable Connected!Now, Waiting for DNW to transmit dataDownload Done!! Download Address: 0x42000000, Download Filesize:0xa53aChecksum is being calculated.Checksum O.K.TINY4412 # dnw 0x40600000OTG cable Connected!Now, Waiting for DNW to transmit dataDownload Done!! Download Address: 0x40600000, Download Filesize:0x43b5d0Checksum is being calculated.....Checksum O.K.TINY4412 # bootm 0x40600000 0x41000000 0x42000000## Booting kernel from Legacy Image at 40600000 ...   Image Name:   Linux-4.4.0-gbd49c0f-dirty   Image Type:   ARM Linux Kernel Image (uncompressed)   Data Size:    4437392 Bytes = 4333 KiB   Load Address: 40008000   Entry Point:  40008000   Verifying Checksum ... OK## Loading init Ramdisk from Legacy Image at 41000000 ...   Image Name:   ramdisk   Image Type:   ARM Linux RAMDisk Image (gzip compressed)   Data Size:    2585838 Bytes = 2525 KiB   Load Address: 00000000   Entry Point:  00000000   Verifying Checksum ... OK## Flattened Device Tree blob at 42000000   Booting using the fdt blob at 0x42000000   Loading Kernel Image ... OKOK## Loading init Ramdisk from Legacy Image at 41000000 ...   Image Name:   ramdisk   Image Type:   ARM Linux RAMDisk Image (gzip compressed)   Data Size:    2585838 Bytes = 2525 KiB   Load Address: 00000000   Entry Point:  00000000   Verifying Checksum ... OK   Loading Ramdisk to 43a84000, end 43cfb4ee ... OK   Loading Device Tree to 413f2000, end 413ff539 ... OKStarting kernel ...Uncompressing Linux... done, booting the kernel.[    0.000000] Booting Linux on physical CPU 0xa00[    0.000000] Linux version 4.4.0-gbd49c0f-dirty (root@ubuntu) (gcc version 4.8.3 20140320 (prerelease) (Sourcery CodeBench Lite 2014.05-29) ) #24 SMP PREEMPT Tue Jan 19 05:39:48 PST 2016[    0.000000] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=10c5387d[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache[    0.000000] Machine model: FriendlyARM TINY4412 board based on Exynos4412[    0.000000] bootconsole [earlycon0] enabled[    0.000000] cma: Reserved 64 MiB at 0x7bc00000[    0.000000] Memory policy: Data cache writealloc[    0.000000] Samsung CPU ID: 0xe4412011[    0.000000] PERCPU: Embedded 12 pages/cpu @ef79b000 s18816 r8192 d22144 u49152[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 260352[    0.000000] Kernel command line: root=/dev/ram0 rw rootfstype=ext4 console=ttySAC0,115200 init=/linuxrc earlyprintk[    0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)[    0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)[    0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)[    0.000000] Memory: 960832K/1047552K available (5863K kernel code, 292K rwdata, 2284K rodata, 440K init, 315K bss, 21184K reserved, 65536K cma-reserved, 195584K highmem)[    0.000000] Virtual kernel memory layout:[    0.000000]     vector  : 0xffff0000 - 0xffff1000   (   4 kB)[    0.000000]     fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)[    0.000000]     vmalloc : 0xf0800000 - 0xff800000   ( 240 MB)[    0.000000]     lowmem  : 0xc0000000 - 0xf0000000   ( 768 MB)[    0.000000]     pkmap   : 0xbfe00000 - 0xc0000000   (   2 MB)[    0.000000]     modules : 0xbf000000 - 0xbfe00000   (  14 MB)[    0.000000]       .text : 0xc0008000 - 0xc07fd188   (8149 kB)[    0.000000]       .init : 0xc07fe000 - 0xc086c000   ( 440 kB)[    0.000000]       .data : 0xc086c000 - 0xc08b52f0   ( 293 kB)[    0.000000]        .bss : 0xc08b8000 - 0xc0906d28   ( 316 kB)[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1[    0.000000] Preemptible hierarchical RCU implementation.[    0.000000]  Build-time adjustment of leaf fanout to 32.[    0.000000]  RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4.[    0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=32, nr_cpu_ids=4[    0.000000] NR_IRQS:16 nr_irqs:16 16[    0.000000] GIC physical location is 0x10490000[    0.000000] L2C: platform modifies aux control register: 0x02070000 ->; 0x3e470001[    0.000000] L2C: platform provided aux values permit register corruption.[    0.000000] L2C: DT/platform modifies aux control register: 0x02070000 ->; 0x3e470001[    0.000000] L2C-310 enabling early BRESP for Cortex-A9[    0.000000] L2C-310: enabling full line of zeros but not enabled in Cortex-A9[    0.000000] L2C-310 dynamic clock gating enabled, standby mode enabled[    0.000000] L2C-310 cache controller enabled, 16 ways, 1024 kB[    0.000000] L2C-310: CACHE_ID 0x4100c4c8, AUX_CTRL 0x4e470001[    0.000000] Exynos4x12 clocks: sclk_apll = 466666667, sclk_mpll = 800000000[    0.000000]  sclk_epll = 96000000, sclk_vpll = 108000000, arm_clk = 1400000000[    0.000000] Switching to timer-based delay loop, resolution 41ns[    0.000000] clocksource: mct-frc: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns[    0.000003] sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns[    0.008035] Console: colour dummy device 80x30[    0.012425] Calibrating delay loop (skipped), value calculated using timer frequency.. 48.00 BogoMIPS (lpj=120000)[    0.022827] pid_max: default: 32768 minimum: 301[    0.027579] Mount-cache hash table entries: 2048 (order: 1, 8192 bytes)[    0.034206] Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes)[    0.041686] CPU: Testing write buffer coherency: ok[    0.046640] CPU0: thread -1, cpu 0, socket 10, mpidr 80000a00[    0.052536] Setting up static identity map for 0x400082c0 - 0x40008318[    0.099784] CPU1: thread -1, cpu 1, socket 10, mpidr 80000a01[    0.114774] CPU2: thread -1, cpu 2, socket 10, mpidr 80000a02[    0.129775] CPU3: thread -1, cpu 3, socket 10, mpidr 80000a03[    0.129815] Brought up 4 CPUs[    0.150143] SMP: Total of 4 processors activated (192.00 BogoMIPS).[    0.156477] CPU: All CPU(s) started in SVC mode.[    0.161676] devtmpfs: initialized[    0.173957] VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 4[    0.181783] lcd0-power-domain@10023C80 has as child subdomain: tv-power-domain@10023C20.[    0.190155] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 9556302231375000 ns[    0.201755] pinctrl core: initialized pinctrl subsystem[    0.207668] NET: Registered protocol family 16[    0.213539] DMA: preallocated 256 KiB pool for atomic coherent allocations[    0.234740] cpuidle: using governor ladder[    0.249735] cpuidle: using governor menu[    0.254286] exynos-audss-clk 3810000.clock-controller: setup completed[    0.306823] SCSI subsystem initialized[    0.310855] usbcore: registered new interface driver usbfs[    0.316329] usbcore: registered new interface driver hub[    0.321714] usbcore: registered new device driver usb[    0.327898] Advanced Linux Sound Architecture Driver Initialized.[    0.335087] clocksource: Switched to clocksource mct-frc[    0.349988] missing cooling_device property[    0.354099] failed to build thermal zone cpu-thermal: -2[    0.359566] NET: Registered protocol family 2[    0.364266] TCP established hash table entries: 8192 (order: 3, 32768 bytes)[    0.371286] TCP bind hash table entries: 8192 (order: 5, 163840 bytes)[    0.377936] TCP: Hash tables configured (established 8192 bind 8192)[    0.384305] UDP hash table entries: 512 (order: 2, 24576 bytes)[    0.390258] UDP-Lite hash table entries: 512 (order: 2, 24576 bytes)[    0.396795] NET: Registered protocol family 1[    0.401289] RPC: Registered named UNIX socket transport module.[    0.407131] RPC: Registered udp transport module.[    0.411902] RPC: Registered tcp transport module.[    0.416674] RPC: Registered tcp NFSv4.1 backchannel transport module.[    0.423325] Trying to unpack rootfs image as initramfs...[    0.429054] rootfs image is not initramfs (no cpio magic); looks like an initrd[    0.442728] Freeing initrd memory: 2528K (c3a84000 - c3cfc000)[    0.449900] futex hash table entries: 1024 (order: 4, 65536 bytes)[    0.465272] romfs: ROMFS MTD (C) 2007 Red Hat, Inc.[    0.470817] bounce: pool size: 64 pages[    0.474564] io scheduler noop registered[    0.478570] io scheduler deadline registered[    0.483072] io scheduler cfq registered (default)[    0.492532] dma-pl330 12680000.pdma: Loaded driver for PL330 DMAC-141330[    0.499160] dma-pl330 12680000.pdma:         DBUFF-32x4bytes Num_Chans-8 Num_Peri-32 Num_Events-32[    0.510651] dma-pl330 12690000.pdma: Loaded driver for PL330 DMAC-141330[    0.517272] dma-pl330 12690000.pdma:         DBUFF-32x4bytes Num_Chans-8 Num_Peri-32 Num_Events-32[    0.526575] dma-pl330 12850000.mdma: Loaded driver for PL330 DMAC-141330[    0.533201] dma-pl330 12850000.mdma:         DBUFF-64x8bytes Num_Chans-8 Num_Peri-1 Num_Events-32[    0.601269] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled[    0.608816] 13800000.serial: ttySAC0 at MMIO 0x13800000 (irq = 44, base_baud = 0) is a S3C6400/10[    0.617669] console [ttySAC0] enabled[    0.617669] console [ttySAC0] enabled[    0.624994] bootconsole [earlycon0] disabled[    0.624994] bootconsole [earlycon0] disabled[    0.633916] 13810000.serial: ttySAC1 at MMIO 0x13810000 (irq = 45, base_baud = 0) is a S3C6400/10[    0.634277] 13820000.serial: ttySAC2 at MMIO 0x13820000 (irq = 46, base_baud = 0) is a S3C6400/10[    0.634631] 13830000.serial: ttySAC3 at MMIO 0x13830000 (irq = 47, base_baud = 0) is a S3C6400/10[    0.639182] [drm] Initialized drm 1.1.0 20060810[    0.652946] brd: module loaded[    0.657821] loop: module loaded[    0.658627] usbcore: registered new interface driver r8152[    0.658763] usbcore: registered new interface driver asix[    0.659855] usbcore: registered new interface driver ax88179_178a[    0.665958] usbcore: registered new interface driver cdc_ether[    0.671772] usbcore: registered new interface driver smsc75xx[    0.677506] usbcore: registered new interface driver smsc95xx[    0.683217] usbcore: registered new interface driver net1080[    0.688858] usbcore: registered new interface driver cdc_subset[    0.694760] usbcore: registered new interface driver zaurus[    0.700345] usbcore: registered new interface driver cdc_ncm[    0.706295] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver[    0.712416] ehci-exynos: EHCI EXYNOS driver[    0.716700] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver[    0.722742] ohci-exynos: OHCI EXYNOS driver[    0.727264] usbcore: registered new interface driver usb-storage[    0.733431] mousedev: PS/2 mouse device common for all mice[    0.739205] s3c-rtc 10070000.rtc: failed to find rtc source clock[    0.744539] s3c-rtc: probe of 10070000.rtc failed with error -2[    0.750636] i2c /dev entries driver[    0.755967] device-mapper: ioctl: 4.34.0-ioctl (2015-10-28) initialised: [e-mail][    0.763141] sdhci: Secure Digital Host Controller Interface driver[    0.768478] sdhci: Copyright(c) Pierre Ossman[    0.772952] Synopsys Designware Multimedia Card Interface Driver[    0.780793] usbcore: registered new interface driver usbhid[    0.784347] usbhid: USB HID core driver[    0.791116] NET: Registered protocol family 10[    0.793128] sit: IPv6 over IPv4 tunneling driver[    0.797746] NET: Registered protocol family 17[    0.801655] NET: Registered protocol family 15[   0.806225] Registering SWP/SWPB emulation handler[    0.812058] hctosys: unable to open rtc device (rtc0)[    0.827998] ALSA device list:[    0.828035]   No soundcards found.[    0.828678] RAMDISK: gzip image found at block 0[    0.970206] EXT4-fs (ram0): mounted filesystem wirdered data mode. Opts: (null)[    0.970301] VFS: Mounted root (ext4 filesystem) on device 1:0.[    0.970419] devtmpfs: mounted[    0.970694] Freeing unused kernel memory: 440K (c07fe000 - c086c000)Please press Enter to activate this console. [root@tiny4412 ]#