openwrt DTSI文件解译

http://blog.csdn.net/hui523hui523hui523/article/details/38681849

build_dir/target-mipsel_24kec+dsp_uClibc-0.9.33.2/linux-ramips_rt305x/linux-3.10.36/arch/mips/ralink/dts/rt3050.dtsi

/ {
    #address-cells = <1>;
    #size-cells = <1>;
    compatible = "ralink,rt3050-soc", "ralink,rt3052-soc", "ralink,rt3350-soc";

    cpus {
        cpu@0 {
            compatible = "mips,mips24KEc";
        };
    };

    chosen {
        bootargs = "console=ttyS0,57600";
    };

    cpuintc: cpuintc@0 {
        #address-cells = <0>;
        #interrupt-cells = <1>;
        interrupt-controller;
        compatible = "mti,cpu-interrupt-controller";
    };

    palmbus@10000000 {   //地址
        compatible = "palmbus";
        reg = <0x10000000 0x200000>;
        ranges = <0x0 0x10000000 0x1FFFFF>;

        #address-cells = <1>;
        #size-cells = <1>;

        sysc@0 {
            compatible = "ralink,rt3052-sysc", "ralink,rt3050-sysc";
            reg = <0x0 0x100>;
        };

        timer@100 {
            compatible = "ralink,rt3052-timer", "ralink,rt2880-timer";
            reg = <0x100 0x20>;

            interrupt-parent = <&intc>;
            interrupts = <1>;
        };

        watchdog@120 {
            compatible = "ralink,rt3052-wdt", "ralink,rt2880-wdt";
            reg = <0x120 0x10>;

            resets = <&rstctrl 8>;
            reset-names = "wdt";

            interrupt-parent = <&intc>;
            interrupts = <1>;
        };

        intc: intc@200 {
            compatible = "ralink,rt3052-intc", "ralink,rt2880-intc";
            reg = <0x200 0x100>;

            resets = <&rstctrl 19>;
            reset-names = "intc";

            interrupt-controller;
            #interrupt-cells = <1>;

            interrupt-parent = <&cpuintc>;
            interrupts = <2>;
        };

        memc@300 {
            compatible = "ralink,rt3052-memc", "ralink,rt3050-memc";
            reg = <0x300 0x100>;

            resets = <&rstctrl 20>;
            reset-names = "mc";

            interrupt-parent = <&intc>;
            interrupts = <3>;
        };

        uart@500 {
            compatible = "ralink,rt5350-uart", "ralink,rt2880-uart", "ns16550a";
            reg = <0x500 0x100>;

            resets = <&rstctrl 12>;
            reset-names = "uart";

            interrupt-parent = <&intc>;
            interrupts = <5>;

            reg-shift = <2>;

            status = "disabled";
        };

        gpio0: gpio@600 {
            compatible = "ralink,rt3052-gpio", "ralink,rt2880-gpio";
            reg = <0x600 0x34>; //从0X600开始映射多少地址

            gpio-controller;
            #gpio-cells = <2>;

            ralink,gpio-base = <0>;
            ralink,num-gpios = <24>;
            ralink,register-map = [ 00 04 08 0c
                        20 24 28 2c
                        30 34 ]; //各寄存器的地址

            resets = <&rstctrl 13>;
            reset-names = "pio"; //名字为PIO

            interrupt-parent = <&intc>;
            interrupts = <6>; //中断号为6

            status = "disabled";
        };

        gpio1: gpio@638 {
            compatible = "ralink,rt3052-gpio", "ralink,rt2880-gpio";
            reg = <0x638 0x24>;

            gpio-controller;
            #gpio-cells = <2>;

            ralink,gpio-base = <24>;
            ralink,num-gpios = <16>;
            ralink,register-map = [ 00 04 08 0c
                        10 14 18 1c
                        20 24 ];

            status = "disabled";
        };

        gpio2: gpio@660 {
            compatible = "ralink,rt3052-gpio", "ralink,rt2880-gpio";
            reg = <0x660 0x24>;

            gpio-controller;
            #gpio-cells = <2>;

            ralink,gpio-base = <40>;
            ralink,num-gpios = <12>;
            ralink,register-map = [ 00 04 08 0c
                        10 14 18 1c
                        20 24 ];

            status = "disabled";
        };

        spi@b00 {
            compatible = "ralink,rt3050-spi", "ralink,rt2880-spi";
            reg = <0xb00 0x100>;

            resets = <&rstctrl 18>;
            reset-names = "spi";

            #address-cells = <1>;
            #size-cells = <0>;

            status = "disabled";
        };

        uartlite@c00 {
            compatible = "ralink,rt3052-uart", "ralink,rt2880-uart", "ns16550a";
            reg = <0xc00 0x100>;

            resets = <&rstctrl 19>;
            reset-names = "uartl";

            interrupt-parent = <&intc>;
            interrupts = <12>;

            reg-shift = <2>;
        };

    };

    rstctrl: rstctrl {
        compatible = "ralink,rt3050-reset", "ralink,rt2880-reset";
        #reset-cells = <1>;
    };

    ethernet@10100000 {
        compatible = "ralink,rt3050-eth";
        reg = <0x10100000 10000>;

        interrupt-parent = <&cpuintc>;
        interrupts = <5>;

        status = "disabled";
    };

    esw@10110000 {
        compatible = "ralink,rt3050-esw";
        reg = <0x10110000 8000>;

        interrupt-parent = <&intc>;
        interrupts = <17>;

        status = "disabled";
    };

    wmac@10180000 {
        compatible = "ralink,rt3050-wmac", "ralink,rt2880-wmac";
        reg = <0x10180000 40000>;

        interrupt-parent = <&cpuintc>;
        interrupts = <6>;

        status = "disabled";
    };

    usb@101c0000 {
        compatible = "ralink,rt3050-usb", "snps,dwc2";
        reg = <0x101c0000 40000>;

        interrupt-parent = <&intc>;
        interrupts = <18>;

        resets = <&rstctrl 22>;
        reset-names = "otg";

        status = "disabled";
    };
}

在执行完unflatten_device_tree()后，DTS节点信息被解析出来，保存到allnodes链表中，allnodes会在后面被用到。

随后，当系统启动到board文件时，会调用.init_machine，高通8974平台对应的是msm8974_init()。接着调用of_platform_populate(....)接口，加载平台总线和平台设备。至此，系统平台上的所有已配置的总线和设备将被注册到系统中。注意：不是dtsi文件中所有的节点都会被注册，在注册总线和设备时，会对dts节点的状态作一个判断，如果节点里面的status属性没有被定义，或者status属性被定义了并且值被设为“ok”或者“okay”，其他情况则不被注册到系统中。