On Wed, Nov 14, 2012 at 10:19 AM, Stefano Babic sbabic@denx.de wrote:
On 14/11/2012 11:29, Otavio Salvador wrote:
Hi Otavio,
In the text you have the offset to save the image onto a NAND offset so I fail to see how it'd be used for SD-Card.
Can you elaborate it a bit?
No, I can't without introducing errors. Current code supports Falcon only booting from NAND - I do not think that it is a big thing to use another media, but it is not yet done. This document must
So I'd say to drop the SD-Card from the document.
+and can be generalized seen as a way to start an image performing the minimum +required initialization. SPL initializes mainly the RAM controller, and after +that copies U-Boot image into the memory. The "Falcon" mode extends this way +allowing to start the Linux kernel directly from SPL. A new command is added +to U-Boot to prepare the parameters that SPL must pass to the kernel, using +ATAGS or Device Tree. + +Falcon adds a command under U-Boot to reuse all code responsible to prepare +the interface with the kernel. In usual U-boot systems, these parameters are +generated each time before loading the kernel, passing to Linux the address +in memory where the parameters can be read. +With falcon, this snapshot can be saved into persistent storage and SPL is +informed to load it before running the kernel.You mix Falcon and falcon.
You're right, there are already comments about this. This will be fixed globally in V3 (I will use Falcon Mode consistently).
I'd say you always use Falcon as it is the name of the feature so it ought to be in upper case. Another thing, 'With falcon, ' ought to be move to the previous line or have an empty line before it.
Ok
+To boot the kernel, these steps under a Falcon-aware U-Boot are required: + +1. Boot the board into U-Boot. +Use the "spl export" command to generate the kernel parameters area or the DT. +U-boot runs as when it boots the kernel, but stops before passing the control +to the kernel. + +2. Saves the prepared snapshot into persistent media. +The address where to save it must be configured into board configuration +file (CONFIG_CMD_SPL_NAND_OFS for NAND).And for others?
Not yet implemented, patches welcome ! But you are right, there is already a patch to use a NOR flash that should flow soon into mainline. I will check and add documentation for it. For the orher media, the document must be updated together when they will be full supported.
+3. Boot the board into "Falcon" mode. SPL will load the kernel andcopy
+the parameters area to the required address. + +It is required to implement a custom mechanism to select if SPL loads U-Boot +or another image. +The value of a GPIO is a simple way to operate the selection, as well as +reading a character from the SPL console if CONFIG_SPL_CONSOLE isset.
An empty line before "The value"?
Ok
Best regards, Stefano Babic
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