i.MX Processors中的主题 ROM API for DCD process

ROM API for DCD process

ArnaudMouiche — Wed, 13 Mar 2013 12:50:55 GMT

hi all,

I'm currently developing a tiny boot for eeprom on imx6sl for loading u-boot from NAND SPI.

Everything is fine except I'm too lazy to re-write a DCD processor to load the u-boot DCD part.

Is there an official ROM API entry to call for this purpose ?

thanks.

Arnaud

Re: ROM API for DCD process

fabio_estevam — Wed, 13 Mar 2013 16:31:25 GMT

Do you mean SPI flash?

If so, you can use the same DCD configuration that is used to boot from SD card:

uboot-imx.git - Freescale i.MX u-boot Tree

and just flash u-boot into offset 0x400 of your SPI Flash.

Re: ROM API for DCD process

ArnaudMouiche — Wed, 13 Mar 2013 17:04:35 GMT

No, I really mean "SPI NAND flash" (not SPI NOR, not parallel NAND), so something which is not directly bootable by the imx6SL ROM.

That's why the first stage will be a 4KB bootloader on eeprom, knowning just enough of the bad blocks & bad bits to look for multiple copies of uboot inside this Nand.

Since I want to keep the uboot header (IVT+ DCD...) as similar as the original, it must manage DCD process and/or plugins inside this first stage, or at least, forward the process to the ROM code (through a possible ROM API)

I don't want to put the DCD part inside this 4KB, since:

- 4KB is already very small

- if possible, I don't want to update this first stage when the DDR parameters will need to change (experience shows It can be frequent...)

Regards,

Arnaud

Re: ROM API for DCD process

Yuri — Thu, 14 Mar 2013 03:45:13 GMT

There were several discussions about the i.MX6 ROM API (what is it, how to use). The recent recommendation is to avoid
use the ROM API (it is not well documented, it is not clear if it will not be changed in next releases).

Re: ROM API for DCD process

ArnaudMouiche — Thu, 14 Mar 2013 08:34:20 GMT

ok fine.

anyway a DCD processor doesn't request too much space.

regards,

arnaud

Re: ROM API for DCD process

JerryFan — Mon, 19 Aug 2013 07:55:36 GMT

Hi ArnaudMouiche,

Any update? Did you ever implemented this successfully?

B.R
Jerry

Re: ROM API for DCD process

ArnaudMouiche — Mon, 19 Aug 2013 17:38:54 GMT

Hello Jerry

Yes, I implemented all what I want successfully.

The DCD stuff was not complicated at all, just consuming few but important

code bytes.

Regards,

Arnaud

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