硬件:
核心板 : Tiny4412-1306-Schematic
底板 : Tiny4412SDK-1308(没有micro USB)其他都一样
参考博客:https://www.cnblogs.com/pengdonglin137/p/5159032.html
修改设备树文件:
diff --git a/arch/arm/boot/dts/exynos4412-tiny4412.dts b/arch/arm/boot/dts/exynos4412-tiny4412.dts
index 305d57d..f41a11a 100644
--- a/arch/arm/boot/dts/exynos4412-tiny4412.dts
+++ b/arch/arm/boot/dts/exynos4412-tiny4412.dts
@@ -105,7 +105,22 @@ mmc_reg: regulator@0{
cd-inverted;
status = "okay";
};
-
+&mshc_0 {
+ num-slots = <1>;
+ broken-cd;
+ non-removable;
+ card-detect-delay = <200>;
+ vmmc-supply = <&mmc_reg>;
+ clock-frequency = <400000000>;
+ samsung,dw-mshc-ciu-div = <0>;
+ samsung,dw-mshc-sdr-timing = <2 3>;
+ samsung,dw-mshc-ddr-timing = <1 2>;
+ pinctrl-0 = <&sd4_clk &sd4_cmd &sd4_bus4 &sd4_bus8>;
+ pinctrl-names = "default";
+ status = "okay";
+ bus-width = <8>;
+ cap-mmc-highspeed;
+};
&serial_0 {
status = "okay";
};
启动重要log:
[ 2.363233] mmc1: MAN_BKOPS_EN bit is not set
[ 2.364010] mmc_host mmc1: Bus speed (slot 0) = 50000000Hz (slot req 52000000Hz, actual 50000000HZ div = 0)
[ 2.364363] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 52000000Hz, actual 50000000HZ div = 1)
[ 2.364906] mmc1: new DDR MMC card at address 0001
[ 2.370622] mmcblk0: mmc1:0001 M4G1YC 3.64 GiB
[ 2.374428] mmcblk0boot0: mmc1:0001 M4G1YC partition 1 2.00 MiB
[ 2.380386] mmcblk0boot1: mmc1:0001 M4G1YC partition 2 2.00 MiB
[ 2.391302] mmcblk0rpmb: mmc1:0001 M4G1YC partition 3 128 KiB
[ 2.392761] mmcblk0: p1 p2 p3 p4
[ 2.519538] mmc0: new high speed SDHC card at address aaaa
[ 2.525358] mmcblk1: mmc0:aaaa SS08G 7.40 GiB
[ 2.527088] mmcblk1: p1 p2
启动后,查看:
[root@tiny4412 ]# ls /dev/mmc*
/dev/mmcblk0 /dev/mmcblk0p1 /dev/mmcblk0p4 /dev/mmcblk1p1
/dev/mmcblk0boot0 /dev/mmcblk0p2 /dev/mmcblk0rpmb /dev/mmcblk1p2
/dev/mmcblk0boot1 /dev/mmcblk0p3 /dev/mmcblk1
现在想把uImage dtb rootfs都放在emmc中,以后可以单独启动。
设置环境变量:
set bootcmd "ext2load mmc 0:2 0x40000000 uImage;ext2load mmc 0:2 0x42000000 exynos4412-tiny4412.dtb;bootm 0x40000000 - 0x42000000"
setenv bootargs 'root=/dev/mmcblk0p3 rw console=ttySAC0,115200 init=/linuxrc'
save
启动后,查看分区大小:
[root@tiny4412 ]# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 1.9G 10.6M 1.8G 1% /
devtmpfs 470.6M 0 470.6M 0% /dev
tmpfs 502.8M 0 502.8M 0% /tmp
成功,那个通过SDMMC启动并挂载的问题,后边再解决。