[U-Boot] [PATCH 2/2] am335x_evm: Update, document Falcon Mode support

Tom Rini trini at ti.com
Fri Jul 5 14:51:03 CEST 2013


On Thu, Jul 04, 2013 at 07:39:48AM +0000, Romain Izard wrote:
> Tom> +A further word of warning about using eMMC and partition tables.  When
> Tom> +working with SD cards we can get away with erasing small areas at a time,
> Tom> +however on eMMC we must keep erases aligned to eraseblocks and thus the
> Tom> +first erase we issue will erase the partition table.
> 
> Peter> Really? I thought eMMC behaved just like SD cards?
> 
> Tom> Yes, really.  We know what the erase block size is, and round our
> Tom> commands, probably because we really have to.  SD cards take care of
> Tom> things for us, for better or worse.
> 
> But why do we bother with erasing the eMMC in the first place? The erase
> commands are wholly optional, and only make sense as a TRIM mechanism,
> which is not our case as we will fill the memory as soon as it has been
> erased.
> 
> There is no problem in writing directly in the memory, even if it has
> not been erased previously. Or is it a measure to detect interrupted
> writes ?

I hadn't thought of it like that, I had been thinking of it like NAND
for some reason.  I'll update the instructions (and write a bunch of
garbage first) and re-confirm things.  Thanks!

-- 
Tom
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