[PATCH] qemu: aspeed_smc: Calculate checksum on normal DMA

[Christian Svensson]

Hi,

Thanks for the review.

On Mon, Nov 12, 2018 at 3:39 PM Cédric Le Goater <clg at kaod.org> wrote:
> The datasheet is not very clear on the topic.

I won't argue there.

> and one could understand that under Normal DMA operation, there is
> no Checksum accumulation.

Indeed, that's what I thought as well. Then my question to myself was that
since that means that you can either 1) transfer data or 2) calculate the
checksum it seems like a pretty useless feature.

If you look at 8.6.2 DMA CheckSum Calculation Mode (for ast2400 at least)
you
see the sentence:
> 5. FMC80[2] is set when only checksum calculation is necessary, no data
movement

Which I take to read that you can execute the whole section and you will
get a checksum + data transfer, but if you set FMC80[2] then you get the
checksum, but no data movement.

> do you have a firmware doing so you could share ? I would like to check
> for the ast2500.

I have my own firmware here:
https://github.com/u-root/u-bmc/blob/07979a696df4351ec6dbb424ca80a5ebcc2eda1d/platform/ast2400/boot/main.S

Cheers,
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