About QUIRK_BROKEN_AUTO_CMD23 in i.MX6DQ.

[keitanagashima]

Dear All,

Hello. I have a question about changing "ChunkSize" by CMD23.

My customer wants to change the ChunkSize of eMMC by CMD23 to reduce the erase count in SLC area.

And, they are using BSP L3.0.35_4.1.0.

But, the NXP source code doesn't use auto cmd23 temporarily.

Refer to below thread.

linux-2.6-imx.git - Freescale i.MX Linux Tree

+ if (cpu_is_mx6())

+ host->quirks2 |= SDHCI_QUIRK_BROKEN_AUTO_CMD23,

+

Next, refer to latest BSP(L3.14.52_1.1.0).

The above patch wasn't found.

linux-2.6-imx.git - Freescale i.MX Linux Tree

[Question]

Q1.

Why does NXP prohibit the use of this code?

(I didn't understand the description of ENGR00178290-2 well...)

-----

if (cpu_is_mx6())

             host->quirks2 |= SDHCI_QUIRK_BROKEN_AUTO_CMD23;

-----

Q2.

What influence is there if the user uses this code?

Best Regards,

Keita

[keitanagashima]

Do you have any update?

Best Regards,

Keita

[igorpadykov · Accepted solution]

Hi Keita

usage CMD23 is optional accrding to sd/emmc specifications and it is

not supported by i.MX6 uSDHC according to Table 67-5 "Commands for MMC/SD/SDIO

Cards" i.MX6DQ Reference Manual (rev.3  7/2015)

http://cache.freescale.com/files/32bit/doc/ref_manual/IMX6DQRM.pdf

Best regards

igor

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[keitanagashima]

Dear Igor,

Sorry. Let me check again.

> it is not supported by i.MX6 uSDHC according to Table 67-5 "Commands for MMC/SD/SDIO

> Cards" i.MX6DQ Reference Manual (rev.3  7/2015)

What is your meaning of "not supported"?

Which is right understanding?

ex.1) uSDHC doesn't send the CMD23 even if it tries to send CMD23.

ex.2) NXP didn't test the CMD23. So, NXP doesn't know whether or not it is possible to send CMD23.

Best Regards,

Keita

[igorpadykov]

Hi Keita

uSDHC doesn't send the CMD23, it even does not try to send CMD23.

Best regards

igor