最近我获得了R-CAR M3开发委员会。通过遵循elinux.org/.../yocto-gen3
的步骤，我成功地用yocto 3.9.0构建了一个嵌入式Linux图像。我还按照elinux.org/.../m3sk。
上的步骤更新板的固件现在，我正在尝试启动Linux图像形成SD卡，但是当我打开板时，我会收到错误" MMC Init Fail"。我知道我可以访问SD卡并加载保存在那里的图像。但是，当试图从SD卡启动时，它会停止引导并显示以下消息" MMC0：错误-110同时初始化MMC卡"
尝试启动时此错误似乎是因为板无法初始化MMC。有人面临同样的问题吗？有人可以帮我解决吗？
引导日志
Welcome to minicom 2.7
OPTIONS: I18n
Compiled on Nov 15 2018, 20:18:47.
Port /dev/ttyUSB0, 22:57:14
Press CTRL-A Z for help on special keys
[ 0.000190] NOTICE: BL2: R-Car Gen3 Initial Program Loader(CA57) Rev.1.0.21
[ 0.005752] NOTICE: BL2: PRR is R-Car M3 Ver.1.0
[ 0.010421] NOTICE: BL2: Board is Starter Kit Rev.1.0
[ 0.015533] NOTICE: BL2: Boot device is HyperFlash(80MHz)
[ 0.020959] NOTICE: BL2: LCM state is CM
[ 0.025001] NOTICE: BL2: AVS setting succeeded. DVFS_SetVID=0x53
[ 0.030988] NOTICE: BL2: DDR3200(rev.0.33)NOTICE: [COLD_BOOT]NOTICE: ..0
[ 0.086074] NOTICE: BL2: DRAM Split is 2ch
[ 0.089960] NOTICE: BL2: QoS is default setting(rev.0.19)
[ 0.095463] NOTICE: BL2: Lossy Decomp areas
[ 0.099636] NOTICE: Entry 0: DCMPAREACRAx:0x80000540 DCMPAREACRBx:0x570
[ 0.106721] NOTICE: Entry 1: DCMPAREACRAx:0x40000000 DCMPAREACRBx:0x0
[ 0.113633] NOTICE: Entry 2: DCMPAREACRAx:0x20000000 DCMPAREACRBx:0x0
[ 0.120548] NOTICE: BL2: v1.4(release):15dba6b
[ 0.125038] NOTICE: BL2: Built : 05:48:04, Feb 18 2019
[ 0.130225] NOTICE: BL2: Normal boot
[ 0.133871] NOTICE: BL2: dst=0xe6320d00 src=0x8180000 len=512(0x200)
[ 0.140254] NOTICE: BL2: dst=0x43f00000 src=0x8180400 len=6144(0x1800)
[ 0.146875] NOTICE: BL2: dst=0x44000000 src=0x81c0000 len=65536(0x10000)
[ 0.154105] NOTICE: BL2: dst=0x44100000 src=0x8200000 len=1048576(0x100000)
[ 0.168928] NOTICE: BL2: dst=0x50000000 src=0x8640000 len=1048576(0x100000)
U-Boot 2015.04 (Feb 17 2019 - 23:28:11)
CPU: Renesas Electronics R8A7796 rev 1.0
Board: M3ULCB
I2C: ready
DRAM: 1.9 GiB
Bank #0: 0x048000000 - 0x07fffffff, 896 MiB
Bank #1: 0x600000000 - 0x63fffffff, 1 GiB
MMC: sh-sdhi: 0, sh-sdhi: 1
MMC init failed
Using default environment
In: serial
Out: serial
Err: serial
Net: Board Net Initialization Failed
No ethernet found.
Hit any key to stop autoboot: 0
=> mmc dev 0
switch to partitions #0, OK
mmc0 is current device
=> mmc info
Device: sh-sdhi
Manufacturer ID: 3
OEM: 5344
Name: SC64G
Tran Speed: 50000000
Rd Block Len: 512
SD version 3.0
High Capacity: Yes
Capacity: 59.5 GiB
Bus Width: 4-bit
Erase Group Size: 512 Bytes
=> ext2ls mmc 0:1 /boot
<DIR> 4096 .
<DIR> 4096 ..
<SYM> 28 Image
18522624 Image-4.14.35-yocto-standard
67069 Image-r8a7796-m3ulcb.dtb
67069 r8a7796-m3ulcb.dtb
67069 Image--4.14.35+git0+118adc53e8-r1-r8a7796-m3ulcb-2019021804481b
=> setenv bootargs 'rw root=/dev/mmcblk0p1 rootfstype=ext4 rootwait'
=> saveenv
Saving Environment to MMC...
MMC init failed
**END OF BOOTING LOG**
**DTB file Information**
sd@ee100000 {
compatible = "renesas,sdhi-r8a7796", "renesas,rcar-gen3-sdhi";
reg = <0x0 0xee100000 0x0 0x2000>;
interrupts = <0x0 0xa5 0x4>;
clocks = <0xa 0x1 0x13a>;
max-frequency = <0xbebc200>;
power-domains = <0x7 0x20>;
resets = <0xa 0x13a>;
status = "okay";
pinctrl-0 = <0x61>;
pinctrl-1 = <0x62>;
pinctrl-names = "default", "state_uhs";
vmmc-supply = <0x63>;
vqmmc-supply = <0x64>;
cd-gpios = <0x65 0xc 0x1>;
bus-width = <0x4>;
sd-uhs-sdr50;
sd-uhs-sdr104;
};
sd@ee120000 {
compatible = "renesas,sdhi-r8a7796", "renesas,rcar-gen3-sdhi";
reg = <0x0 0xee120000 0x0 0x2000>;
interrupts = <0x0 0xa6 0x4>;
clocks = <0xa 0x1 0x139>;
max-frequency = <0xbebc200>;
power-domains = <0x7 0x20>;
resets = <0xa 0x139>;
status = "disabled";
};
sd@ee140000 {
compatible = "renesas,sdhi-r8a7796", "renesas,rcar-gen3-sdhi";
reg = <0x0 0xee140000 0x0 0x2000>;
interrupts = <0x0 0xa7 0x4>;
clocks = <0xa 0x1 0x138>;
max-frequency = <0xbebc200>;
power-domains = <0x7 0x20>;
resets = <0xa 0x138>;
status = "okay";
pinctrl-0 = <0x66>;
pinctrl-1 = <0x67>;
pinctrl-names = "default", "state_uhs";
vmmc-supply = <0x68>;
vqmmc-supply = <0x69>;
bus-width = <0x8>;
mmc-hs200-1_8v;
mmc-hs400-1_8v;
non-removable;
};
sd@ee160000 {
compatible = "renesas,sdhi-r8a7796", "renesas,rcar-gen3-sdhi";
reg = <0x0 0xee160000 0x0 0x2000>;
interrupts = <0x0 0xa8 0x4>;
clocks = <0xa 0x1 0x137>;
max-frequency = <0xbebc200>;
power-domains = <0x7 0x20>;
resets = <0xa 0x137>;
status = "disabled";
};
带有renesas yocto版本3.9.0，有一些已经知道的问题在：
上升起https://elinux.org/r-car/board/board/m3sk
（向下滚动到底部）
您应该在MMC驱动程序上应用解决方案。
对于M3SK上的MMC规格，
+ sdhi0: used for sdcard 4-bit bus width
+ sdhi2: used for on-board 8bit eMMC
+ sd-uhs-sdr50: SD UHS SDR50 speed is supported
+ sd-uhs-sdr104: SD UHS SDR104 speed is supported
+ mmc-hs200-1_8v: eMMC HS200 mode(1.8V I/O) is supported
+ mmc-hs400-1_8v: eMMC HS400 mode(1.8V I/O) is supported
也有一些补丁可能处理您的问题：
https://patchwork.kernel.org/patch/9963437/
https://patchwork.kernel.org/patch/9998159/
顺便说一句，您使用的是 amm-tf v1.4，应与u-boot v2018.09一起使用以兼容。
u-boot应支持MMC和SDCARD INIT。您是否尝试使用另一个sdcard？
要更新u-boot-elf.srec，您需要https://github.com/renesas-rcar/flash_writer
- 构建您的flash_writer
- 让设备以SCIF下载模式或USB下载模式启动。键入" ctrl a s"，发送您的xxx.mot
- 请参阅https://elinux.org/r-car/boards/m3sk#flashing_firmware 中的步骤