topic Re: cannot access eMMC in iMX6ul-EVK in i.MX Processors

cannot access eMMC in iMX6ul-EVK

sourabhdas — Tue, 09 Aug 2016 07:23:58 GMT

Hi, I am using imx6ulevk. I want to boot my images from eMMC present in the kit. I followed the "i.MX_Linux_User's_Guide.pdf". So currently I have booted my board with the SD card upto the u-boot prompt. As mentioned in the guide the USDHC2 is the interface for the eMMC and I used the following command to select the eMMC:

=> mmc dev 1 0

It give me the result:
switch to partitions #0, OK
mmc1 is current device

Then I tftp the emmc u-boot image to the board. The image was prebuilt image which I downloaded from NXP website:

tftpboot ${loadaddr} u-boot-imx6ul14x14ddr3arm2_emmc.imx

Then i did mmc write to write it to mmc:

mmc write ${loadaddr} 0x0 0x60000

which gives the result:

MMC write: dev # 1, block # 0, count 393216 ... 393216 blocks written: OK

Then I changed the boot config pin to "0110" to boot the u-boot from eMMC. But I couldn't get any output.

Here is the output of my "mmc list" command:

FSL_SDHC: 0
FSL_SDHC: 1 (SD)

Have I done any thing wrong in selecting the mmc dev?

mmc dev 1 0

Re: cannot access eMMC in iMX6ul-EVK

igorpadykov — Tue, 09 Aug 2016 10:27:08 GMT

Hi Sourabh

u-boot-imx6ul14x14ddr3arm2 is for arm2 board, which is different from EVK board,

also when writing u-boot.imx offset 0x400 should be provided like as :

dd if=u-boot.imx of=/dev/mmcblk0 seek=2 bs=512

Recommended to use mfg tools on link below using attached ucl2.xml

i.MX 6 Series Software and Development Tool|NXP

and build uboot adding +#define CONFIG_MX6UL_EVK_EMMC_REWORK

in include/configs/mx6ul_14x14_evk.h to enable whole 8bit data pin of eMMC

Also one can look at suggestions

Cannot boot from eMMC i.mx6UL EVK

Best regards

igor

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Re: cannot access eMMC in iMX6ul-EVK

sourabhdas — Wed, 10 Aug 2016 10:14:16 GMT

Hi Igorpadykov,

I added #define CONFIG_MX6UL_EVK_EMMC_REWORK in my board include file(mx6ul_14x14_evk.h) and build the image and flash it into my sd card. But after booting the board till the filesystem, I found that the node "/dev/mmcblk0" was not present there. There was only "/dev/mmcblk1", " /dev/mmcblk1p1" and "/dev/mmcblk1p2" that I guess the node for the SD card.

According to my understanding the eMMC was enabled only in the u-boot but not in the DTB file.

You recommend me to use mfg tool. But I want to flash the eMMC from the kernel using dd command. If there any patch available to enable the eMMC inside the DTS file, can you please share?

Re: cannot access eMMC in iMX6ul-EVK

igorpadykov — Wed, 10 Aug 2016 10:23:45 GMT

I am not aware of such patch.

~igor

Re: cannot access eMMC in iMX6ul-EVK

sourabhdas — Wed, 10 Aug 2016 11:48:06 GMT

I mean I checked the dts file (imx6ul-14x14-evk.dts). I checked the pin-muxing of usdhc2, as both the eMMC and SD card connected to usdhc2. I got this:

	pinctrl_usdhc2: usdhc2grp {
	fsl,pins = <
	MX6UL_PAD_NAND_RE_B__USDHC2_CLK	0x10069
	MX6UL_PAD_NAND_WE_B__USDHC2_CMD	0x17059
	MX6UL_PAD_NAND_DATA00__USDHC2_DATA0 0x17059
	MX6UL_PAD_NAND_DATA01__USDHC2_DATA1 0x17059
	MX6UL_PAD_NAND_DATA02__USDHC2_DATA2 0x17059
	MX6UL_PAD_NAND_DATA03__USDHC2_DATA3 0x17059
	>;
	};

As I was not getting the node for eMMC (/dev/mmcblk0) in kernel so my doubt here is where is the muxing of rest of the eMMC pins (DATA4, DATA5, DATA6, DATA7 and RST) in the dts file?