【骚操作】启动阶段改设备DTS的方法

DOT小文哥 LV 8

在设备BSP调试的过程中，经常会出现需要修改DTS的情况，比如调试一个新的屏幕、传感器或者wifi模组，传统的方法是：
在源码中直接修改board.dts文件->重新编译&打包->烧写到设备里
这种方法繁杂，编译和烧写都要花费时间，严重影响开发效率。
因此，全志提供了一个启动阶段DTS调试的方法，可以让我们在启动阶段就把DTS改掉，这次启动加载的就是改后的DTS。
*注：这种修改是一次性的，不可以保存的，只限这次启动的时候生效，断电或者重启就不生效了

1.设备上电过程中串口按住电脑键盘的"s"按键，让设备进入boot：
*注：是真的按住调试的电脑的键盘的s按键，和按住2另设备跳烧录的操作一样（参考：https://d1.docs.aw-ol.com/study/study_4compile/#pc2）
如果进入boot成功，就会有如下log，这时就可以在串口对设备进行DTS修改操作。

（详细log如下）

[188]HELLO! BOOT0 is starting!
[191]BOOT0 commit : 27369ab
[194]set pll start
[196]periph0 has been enabled
[199]set pll end
[200][pmu]: bus read error
[203]board init ok
[205]DRAM only have internal ZQ!!
[208]get_pmu_exist() = -1
[210]DRAM BOOT DRIVE INFO: V0.24
[213]DRAM CLK = 792 MHz
[215]DRAM Type = 3 (2:DDR2,3:DDR3)
[219]DRAMC ZQ value: 0x7b7bfb
[221]DRAM ODT value: 0x42.
[224]ddr_efuse_type: 0x0
[227]DRAM SIZE =1024 M
[231]DRAM simple test OK.
[233]dram size =1024
[235]key press : s
[237]spinand UBOOT_START_BLK_NUM 8 UBOOT_LAST_BLK_NUM 32
[242]block from 8 to 32
[318]Check is correct.
[320]dma 0x2f9f8 int is not used yet
[323]dma 0x2f9f8 int is free, you do not need to free it again
[329]Entry_name        = opensbi
[332]Entry_name        = u-boot
[335]Entry_name        = dtb
[338]Jump to second Boot.

OpenSBI v0.6
   ____                    _____ ____ _____
  / __ \                  / ____|  _ \_   _|
 | |  | |_ __   ___ _ __ | (___ | |_) || |
 | |  | | '_ \ / _ \ '_ \ \___ \|  _ < | |
 | |__| | |_) |  __/ | | |____) | |_) || |_
  \____/| .__/ \___|_| |_|_____/|____/_____|
        | |
        |_|

Platform Name          : T-HEAD Xuantie Platform
Platform HART Features : RV64ACDFIMSUVX
Platform Max HARTs     : 1
Current Hart           : 0
Firmware Base          : 0x40000400
Firmware Size          : 75 KB
Runtime SBI Version    : 0.2

MIDELEG : 0x0000000000000222
MEDELEG : 0x000000000000b1ff
PMP0    : 0x0000000040000000-0x000000004001ffff (A)
PMP1    : 0x0000000040000000-0x000000007fffffff (A,R,W,X)
PMP2    : 0x0000000080000000-0x00000000bfffffff (A,R,W,X)
PMP3    : 0x0000000000020000-0x0000000000027fff (A,▒

U-Boot 2018.05-g0a88ac9 (Apr 30 2021 - 11:23:28 +0000) Allwinner Technology

[00.421]DRAM:  1 GiB
[00.423]Relocation Offset is: 3def0000
[00.427]secure enable bit: 0
[00.429]CPU=1008 MHz,PLL6=600 Mhz,AHB=200 Mhz, APB1=100Mhz  MBus=300Mhz
[00.436]flash init start
[00.438]workmode = 0,storage type = 0
[00.444]sunxi-spinand-phy: not detect any munufacture from id table
[00.450]sunxi-spinand-phy: get spi-nand Model from fdt fail
[00.456]sunxi-spinand-phy: get phy info from fdt fail

device nand0 <nand>, # parts = 4
 #: name                size            offset          mask_flags
 0: boot0               0x00100000      0x00000000      1
 1: uboot               0x00300000      0x00100000      1
 2: secure_storage      0x00100000      0x00400000      1
 3: sys                 0x0fb00000      0x00500000      0

active partition: nand0,0 - (boot0) 0x00100000 @ 0x00000000

defaults:
mtdids  : nand0=nand
mtdparts: mtdparts=nand:1024k@0(boot0)ro,3072k@1048576(uboot)ro,1024k@4194304(secure_storage)ro,-(sys)
[00.794]ubi0: attaching mtd4
[01.190]ubi0: scanning is finished
[01.200]ubi0: attached mtd4 (name "sys", size 251 MiB)
[01.204]ubi0: PEB size: 262144 bytes (256 KiB), LEB size: 258048 bytes
[01.211]ubi0: min./max. I/O unit sizes: 4096/4096, sub-page size 2048
[01.217]ubi0: VID header offset: 2048 (aligned 2048), data offset: 4096
[01.223]ubi0: good PEBs: 1004, bad PEBs: 0, corrupted PEBs: 0
[01.228]ubi0: user volume: 9, internal volumes: 1, max. volumes count: 128
[01.235]ubi0: max/mean erase counter: 2/1, WL threshold: 4096, image sequence number: 0
[01.243]ubi0: available PEBs: 0, total reserved PEBs: 1004, PEBs reserved for bad PEB handling: 40
[01.251]sunxi flash init ok
[01.254]line:714 init_clocks
__clk_init: clk pll_periph0x2 already initialized
register fix_factor clk error
[01.264]drv_disp_init
request pwm success, pwm2:pwm2:0x2000c00.
[01.281]drv_disp_init finish
[01.283]boot_gui_init:start
[01.286]set disp.dev2_output_type fail. using defval=0
[01.478]boot_gui_init:finish
[01.891]LCD open finish
partno erro : can't find partition bootloader
54 bytes read in 0 ms
[02.052]bmp_name=bootlogo.bmp size 3072054
3072054 bytes read in 126 ms (23.3 MiB/s)
[02.402]Loading Environment from SUNXI_FLASH... OK
[02.435]out of usb burn from boot: not need burn key
[02.460]update bootcmd
[02.482]change working_fdt 0x7eaafda8 to 0x7ea8fda8
[02.503]update dts
Hit any key to stop autoboot:  0
=> sssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
Unknown command 'sssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss' - try 'help'
=>
=>

2.要看哪个DTS节点的参数，就输入 fdt list +节点名称
比如查看整个/soc/的DTS：

=> fdt list /soc/
soc@3000000 {
        #address-cells = <0x00000002>;
        #size-cells = <0x00000002>;
        compatible = "simple-bus";
        ranges;        sram_ctrl@3000000 {
        };
        rtc_ccu@7090000 {
        };
        clock@2001000 {
        };
        clock@7010000 {
        };
        interrupt-controller@10000000 {
        };
        uart@2500000 {
        };
        uart@2500400 {
        };
        uart@2500800 {
        };
        uart@2500c00 {
        };
        uart@2501000 {
        };
        uart@2501400 {
        };
        ce@03040000 {
        };
        s_cir@7040000 {
        };
        ir@2003000 {
        };
        deinterlace@5400000 {
        };
        eth@4500000 {
        };
        rtc@7090000 {
        };
        dma-controller@3002000 {
        };
        timer@2050000 {
        };
        watchdog@6011000 {
        };
        mbus-comtroller@3102000 {
        };
        pmu {
        };
        idle {
        };
        pinctrl@2000000 {
        };
        spi@4025000 {
        };
        spi@4026000 {
        };
        twi@2502000 {
        };
        twi@2502400 {
        };
        twi@2502800 {
        };
        twi@2502c00 {
        };
        ledc@2008000 {
        };
        pwm@2000c00 {
        };
        keyboard@2009800 {
        };
        sid@3006000 {
        };
        gpadc@2009000 {
        };
        ths@02009400 {
        };
        rtp@2009c00 {
        };
        codec@2030000 {
        };
        dummy_cpudai@203034c {
        };
        sound@2030340 {
        };
        rpaf-dsp@203034c {
        };
        dmic@2031000 {
        };
        sound@2031050 {
        };
        sounddmic@2031060 {
        };
        daudio@2032000 {
        };
        sounddaudio0@20320a0 {
        };
        daudio@2033000 {
        };
        sounddaudio1@20330a0 {
        };
        daudio@2034000 {
        };
        sounddaudio2@20340a0 {
        };
        hdmiaudio@20340a4 {
        };
        spdif@2036000 {
        };
        soundspdif@2036040 {
        };
        g2d@5410000 {
        };
        disp@5000000 {
        };
        ve@1c0e000 {
        };
        msgbox@0601f000 {
        };
        lcd0@1c0c000 {
        };
        sdmmc@4022000 {
        };
        sdmmc@4020000 {
        };
        sdmmc@4021000 {
        };
        hdmi@5500000 {
        };
        usbc0@0 {
        };
        udc-controller@0x04100000 {
        };
        ehci0-controller@0x04101000 {
        };
        ohci0-controller@0x04101400 {
        };
        usbc1@0 {
        };
        ehci1-controller@0x04200000 {
        };
        ohci1-controller@0x04200400 {
        };
        pwm0@2000c10 {
        };
        pwm1@2000c11 {
        };
        pwm2@2000c12 {
        };
        pwm3@2000c13 {
        };
        pwm4@2000c14 {
        };
        pwm5@2000c15 {
        };
        pwm6@2000c16 {
        };
        pwm7@2000c17 {
        };
        vind@5800800 {
        };
        tvd@05c00000 {
        };
        tvd0@05c01000 {
        };
        card0_boot_para@2 {
        };
        card2_boot_para@3 {
        };
        rfkill@0 {
        };
        btlpm@0 {
        };
        addr_mgt@0 {
        };
};

再比如看pwm0的设置则为：

=> fdt list /soc/pwm0
pwm0@2000c10 {
        compatible = "allwinner,sunxi-pwm0";
        reg = <0x00000000 0x02000c10 0x00000000 0x00000004>;
        reg_base = <0x02000c00>;
        pinctrl-names = "active", "sleep";
        pinctrl-0 = <0x00000056>;
        pinctrl-1 = <0x00000057>;
        status = "okay";
        phandle = <0x00000030>;
};

3.如果要修改某个节点的参数，则使用 fdt set 节点名称参数名称要修改的数值
如 fdt set /soc/disp dev0_do_hpd <0>

4.改好后输入 boot 启动设备即可。

DOT小文哥 LV 8

*注：如果参数值是数字的话，要用"<>"括起来，如：

fdt set /soc/disp/ screen0_output_type <4>

如果是字符串的话要用引号引起来，如：

dt set /soc/disp/ boot_fb0 "000000007eb4d680,780,438,20,1e00,348,17c,438,2bc"

baidxi LV 2

这操作还不够方便，给UBOOT添加一个环境变量
replace_fdt=dtb,raw
再修改sys_partition.fex，添加一个名为dtb的分区，下载文件为正常的sunxi.fex。
更新dtb的时候，只需要用刷机工具更新DTB或区，或者在系统下使用dd把新的DTB写到dtb分区就行了。

这是全志UBOOT自带的功能。