i.MX6 ROM code realy change the SDHCI_WTMK_LVL register value?

[t-iishii]

Hi 

In SDHC driver of Linux( drivers/mmc/host/sdhci-esdhc-imx.c) has following operation.

     /*       * The imx6q ROM code will change the default watermark level setting       * to something insane.  Change it back here.       */      if (is_imx6q_usdhc(imx_data))           writel(0x08100810, host->ioaddr + SDHCI_WTMK_LVL);
Does ROM code realy modify this register?

If so, is it OK to overwrite it to reset value?

I am worried. if ROM code change this register value,

It has some reason to set new value.

Best regards,

Ishii

[igorpadykov]

Hi Ishii

I do not think that it is changed, however one can attach jtag
and check that.

Best regards
igor
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[t-iishii]

Dear Igor

Thank you for your response.

I check it from u-boot command line.

Result is a following.

uSDHC1_WTMK_LVL = 0x08100810

uSDHC2_WTMK_LVL = 0x08100810

uSDHC3_WTMK_LVL = 0x08000880

uSDHC4_WTMK_LVL = 0x08100810

So ROM boot loader or u-boot change the SDHC3_WTMK_LVL register.

Moreover it was setted the WR_WML to 0.

Under this setting, SDHC3 can read/write correctly?

Best regards,

Ishii.

[igorpadykov]

Hi Ishii

SD3 works fine in sabre boards, please use bsps from

http://www.nxp.com/products/microcontrollers-and-processors/arm-processors/i.mx-applications-process... 

Best regards
igor

[t-iishii]

Hello Igor

Thank you for your support.

I check some source code.

It has a register set operation.

But some source is used a different value to set ESDHC_WTMK_LVL register.

For example Android M6.0.1 source code kernel_imx/drivers/mmc/sdhci-esdhc-imx.c

It set a value 0x10401040 to ESDHC_WTMK_LVL register.

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

I must inform a meaning of set value to my customer.

Don't you have detail information about this register more than i.MX6 Refelence Manual?

Best regards,

Ishii

[igorpadykov]

Hi Ishii

sorry I have not more info about of this register value.

Also from my side I did not find that ROM change it.

Best regards
igor

[t-iishii]

Hi Igor

Thank you for your quick response.

And sorry my low understanding.

You say that

"SD3 works fine in sabre boards, please use bsps from"

Your meaning is a

 1) That BSP can work fine.

 2) SD3 work fine both register value 0x08100810 and 0x08000880

Which is a correct answer?

Best regards,

Ishii.

[igorpadykov]

Hi Ishii

yes nxp BSPs work fine.

You can check these BSPs and look at used register value.

Best regards
igor