[英]Deciphering Device Tree
这是我从嵌入式Linux内核上的设备树中摘录的摘录。 这就是我现在的理解:
1) aemif
接口位于物理地址0x30000000
2) aemif
驱动程序位于名为davinci_aemif.c的文件中,它使用名为aemif
的时钟
3) aemif
有2个设备,一个是cs2
,另一个是nand
(我认为这个假设是不正确的)
现在的问题:
1)什么是行reg = <0x21000a00 0x100>;
在做什么? 该如何aemif
它位于0x30000000
处有地址空间0x21000a00
?
2)为什么cs2
定义为cs2@30000000
而不是cs2@1,0
3)什么是行reg = <0x2 0x0 0x8000000 0x6 0x0 0x100>;
在做什么?
4)关于如何设置信号线(ta,rhold,rstrobe等)的任何说明都将有所帮助。
aemif@30000000 {
compatible = "ti,davinci-aemif";
#address-cells = <0x2>;
#size-cells = <0x1>;
reg = <0x21000a00 0x100>;
ranges = <0x2 0x0 0x30000000 0x8000000 0x3 0x0 0x34000000 0x4000000 0x4 0x0 0x38000000 0x4000000 0x5 0x0 0x3c000000 0x4000000 0x6 0x0 0x21000a00 0x100>;
clocks = <0x11>;
clock-names = "aemif";
cs2@30000000 {
compatible = "ti,davinci-cs";
#address-cells = <0x1>;
#size-cells = <0x1>;
ti,davinci-cs-ta = <0xc>;
ti,davinci-cs-rhold = <0x6>;
ti,davinci-cs-rstrobe = <0x17>;
ti,davinci-cs-rsetup = <0x9>;
ti,davinci-cs-whold = <0x8>;
ti,davinci-cs-wstrobe = <0x17>;
ti,davinci-cs-wsetup = <0x8>;
};
nand@2,0 {
compatible = "ti,davinci-nand";
reg = <0x2 0x0 0x8000000 0x6 0x0 0x100>;
#address-cells = <0x1>;
#size-cells = <0x1>;
ti,davinci-chipselect = <0x0>;
ti,davinci-mask-ale = <0x2000>;
ti,davinci-mask-cle = <0x4000>;
ti,davinci-mask-chipsel = <0x0>;
ti,davinci-ecc-mode = "hw";
ti,davinci-ecc-bits = <0x4>;
ti,davinci-nand-use-bbt;
ti,davinci-no-subpage-write;
clocks = <0x11>;
clock-names = "aemif";
partition@0 {
label = "u-boot";
reg = <0x0 0x100000>;
read-only;
};
partition@100000 {
label = "params";
reg = <0x100000 0x80000>;
read-only;
};
partition@180000 {
label = "ubifs";
reg = <0x180000 0x1fe80000>;
};
};
};
您的设备树显然是错误的。
1 / reg = <0x21000a00 0x100>;
通知aemif实际上位于0x21000a00
并具有32个寄存器(0x100 / 4),因此单元地址必须为0x21000a00
: aemif@21000a00
2 /同样,unit-address必须与reg属性匹配,cs2中没有reg属性。
3 / reg = <0x2 0x0 0x8000000 0x6 0x0 0x100>;
reg指节点父级的ranges属性。 在这里,它可以解释为:-从范围0x2开始,在偏移量0x0(即为0x30000000),大小为0x8000000-从范围0x6,偏移量为0x0,大小为0x100
4 /您必须查看具有兼容“ ti,davinci-cs”的字符串的驱动程序,我没有办法,因为它没有成为主流。
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