各位好，公司有款产品用到了 TI的am335x系列处理器，在移植Linux时，查看了官方的SDK里的这个文件：arch/arm/boot/dts/am335x-evm.dts，其中关于nandflash的一段如下（时序部分更改过）：
&gpmc {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&nandflash_pins_s0>;
ranges = <0 0 0x08000000 0x10000000>; /* CS0: 256MB for NAND */
nand@0,0 {
compatible = "ti,omap2-nand";
reg = <0 0 4>; /* CS0, offset 0, IO size 4 */
interrupt-parent = <&gpmc>;
interrupts = <0 IRQ_TYPE_NONE>, /* fifoevent */
<1 IRQ_TYPE_NONE>; /* termcount */
rb-gpios = <&gpmc 1 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */
ti,nand-ecc-opt = "bch8";
ti,elm-id = <&elm>;
nand-bus-width = <16>;
gpmc,device-width = <1>;
gpmc,sync-clk-ps = <0>;
gpmc,cs-on-ns = <0>;
gpmc,cs-rd-off-ns = <6>;
gpmc,cs-wr-off-ns = <6>;
gpmc,adv-on-ns = <0>;
gpmc,adv-rd-off-ns = <8>;
gpmc,adv-wr-off-ns = <8>;
gpmc,we-on-ns = <1>;
gpmc,we-off-ns = <3>;
gpmc,oe-on-ns = <1>;
gpmc,oe-off-ns = <3>;
gpmc,access-ns = <5>;
gpmc,rd-cycle-ns = <6>;
gpmc,wr-cycle-ns = <5>;
gpmc,bus-turnaround-ns = <0>;
gpmc,cycle2cycle-delay-ns = <4>;
gpmc,clk-activation-ns = <0>;
gpmc,wr-access-ns = <5>;
gpmc,wr-data-mux-bus-ns = <0>;
/* MTD partition table */
/* All SPL-* partitions are sized to minimal length
* which can be independently programmable. For
* which can be independently programmable. For
* NAND flash this is equal to size of erase-block */
#address-cells = <1>;
#size-cells = <1>;
partition@0 {
label = "NAND.SPL";
reg = <0x00000000 0x000020000>;
};
partition@1 {
label = "NAND.SPL.backup1";
reg = <0x00020000 0x00020000>;
};
partition@2 {
label = "NAND.SPL.backup2";
reg = <0x00040000 0x00020000>;
};
partition@3 {
label = "NAND.SPL.backup3";
reg = <0x00060000 0x00020000>;
};
partition@4 {
label = "NAND.u-boot-spl-os";
reg = <0x00080000 0x00040000>;
};
partition@5 {
label = "NAND.u-boot";
reg = <0x000C0000 0x00100000>;
};
partition@6 {
label = "NAND.u-boot-env";
reg = <0x001C0000 0x00020000>;
};
partition@7 {
label = "NAND.u-boot-env.backup1";
reg = <0x001E0000 0x00020000>;
};
partition@8 {
label = "NAND.kernel";
reg = <0x00200000 0x00800000>;
};
partition@9 {
label = "NAND.file-system";
reg = <0x00A00000 0x0F600000>;
};
};
};
请问，其中的 reg = <0 0 4>; /* CS0, offset 0, IO size 4 */，这句话中的 “ IO size 4”是什么意思？百思不得其解。。。。
望各位赐教 ！！！
