topic Re: Boot device order in SABRE SD board in i.MX Processors

Boot device order in SABRE SD board

jaiganesh — Fri, 04 Apr 2014 10:34:24 GMT

Hi all,

I am using iMX6q SABRE SD board and I have a query regarding the boot device options. From the "Linux Users Guide" document, I understand that setting the SW6 switch on the board selects the boot device. My question is, does the board have anything like boot device order (such as SW6 is set to boot from SD slot3 but it fails, then it automatically goes to another boot device like SD slot 2 or NAND and tries to boot it from that device). If so, what is the boot device order and is there any way to change the order?

Thanks in advance.

Re: Boot device order in SABRE SD board

Yuri — Fri, 04 Apr 2014 10:50:11 GMT

IMX6 does not have options to select different boot order as, say, it may be done in PC BIOS,

but if (hardware selected) boot device fails the i.MX6 can try boot SD / MMC in so called
SD / MMC Manufacture mode before applying to serial (USB) boot.

Please look at section 8.11 (SD/MMC Manufacture Mode) of the IMX6SDLRM (Rev. 1, 04/2013) for details.

The i.MX6 S/DL in SD/MMC manufacture mode SD or MMC card will be scanned on uSDHC1 and uSDHC2.

If a card is detected and boot image is found in the card, then this boot image will be loaded and executed.

In SD/MMC manufacture mode, CD signal is tested by boot ROM, and pads GPIO_1 and GPIO_4 will be used

as SD1_CD and SD2_CD respectively ; so, this pins should be pulled up /down properly. In particular one can try

to pull down them to avoid entering the SD/MMC manufacture mode.

The boot configuration bit to disable the SD/MMC manufacture mode is BOOT_CFG3[0]. It can be disabled by blowing

the OCOTP fuse OCOTP_CFG4[16] or for GPIO boot override, pull high EIM_A16.

Note : It is supported in i.MX6SDL and i.MX6SL. However, it is not available on i.MX6DQ.

There are differences between i.MX6SDL and i.MX6SL:

In MX6SDL both SD1 and SD2 are used for Manufacturing, the pins used for SD1_CD is GPIO_1

and SD2_CD is GPIO_4.

In MX6SL only SD1 is used for CD, the pin used for CD signal is KEY_ROW7

Have a great day,
Yuri

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Re: Boot device order in SABRE SD board

jaiganesh — Fri, 04 Apr 2014 14:28:30 GMT

Hi Yuri,

Thanks for answer. But you said that SD / MMC Manufacture mode is not applicable in i.MX6DQ which means this option is not available in SABRE SD (Quad Core). Am I right?

Re: Boot device order in SABRE SD board

Yuri — Mon, 07 Apr 2014 04:04:29 GMT

For Quad Core - yes.
But - at least - the schematic contains also the DualLite scheme.

https://www.freescale.com/webapp/Download?colCode=i.MX6_SABRE_SDP_DESIGNFILES&appType=license&location=null&fasp=1&WT_TY…