Plugin Image example

[bonzo]

On the iMX6 Sabre Lite, there is a bin file called iMX6DQ_SPI_touSDHC4.bin which allows boot from SD instead of NOR flash (default)..  It's also known as a "shim".  At first inspection of the binary file, it doesn't seem to follow the rules for a Plugin Image as described in Section 8.7 of the latest reference manual Rev 0. 

Is this shim the same as a Plugin Image?

Does anyone have the source for this binary image?

I am wondering if there is any source code examples for implementing a Plugin Image to change the boot source for iMX6.

Brad

Original Attachment has been moved to: iMX6DQ_SPI_to_uSDHC4.bin.zip

[DirkBehme · Accepted solution]

Several answers :smileywink:

First, regarding the iMX6DQ_SPI_touSDHC4.bin for the SabreLite: No, to my understanding this doesn't implement the plugin logic. If you disassemble this small binary you will see that it does the following:

a) it writes a magic to a register. To my understanding the content of this registers stays valid while a (watchdog) reset and with this tells the boot ROM "don't use the default boot mode, but use the boot config given in the second register"

b) sets the (SD) boot config in a second register. The content of this register stays valid over a reset, too, an is then taken by the boot ROM as the boot mode.

c) issue a watchdog reset to make the boot ROM take the boot mode configuration written in steps (a) and (b) above

Second, regarding plug in image examples. I'm interested in some examples for this, too. Maybe this would be a nice topic for an Application Note? :smileywink: What I know, but haven't looked into yet, are some patches on the U-Boot mailing list implementing the plugin concept to make one image boot on the i.MX6 Quad and Solo. Have a look to the whole patch series

[U-Boot] [PATCH V2 00/21] Add mx6solo/mx6duallite support