eMMC5.0 Boot with Bus Width=8bit access for i.MX6

[yuuki]

Dear all,

Our customer uses eMMC5.0 device.
And they make a system boot from eMMC with Bus Width=8bit(BOOT_CFG2[7:5]=010).

In this case, system can not boot.

When Bus Width is set to 4bit(BOOT_CFG2[7:5]=001) and U-Boot is set as 4bit, system is able to boot.
However, boot speed is very slow.

Is there a way to be accessed by 8 bits at booting from eMMC5.0 device?

May I have advice?

Best Regards,
Yuuki

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[igorpadykov]

Hi Yuuki

what processor and SD port used in the case ?

Best regards

igor

[yuuki]

Dear Igor-san,

Thank you for your support.

Prosessor is i.MX6 solo(MCIMX6S5EVM10AB).

SD port is SD4.

Please advise of your findings.

Best Regards,

Yuuki

[igorpadykov]

Hi Yuuki

8-bit eMMC is working fine on i.MX6 reference

board Sabre SPF-27392  p.5

i.MX6_SABRE_SDP_DESIGNFILES

probably there are layout errors or issues

related to layout (signtal integrity), one can try

to check signals by oscilloscope.

Best regards

igor

[rahulsoni]

Hello Igor,

I have the same configuration as Yuuki. i.MX6 Solo and eMMC 5.0 @ SD4 port. I see the eMMC on kernel but can not see eMMC on u boot due to which I'm not able to boot my device over eMMC. Below are my boot configuration settings-

CFG1[7:0]- 01101000

CFG2[7:0]- 11011000

Please help me to resolve this problem.

Thanks in advance.