On Tue, Jun 20, 2023 at 01:17:09PM -0500, Nishanth Menon wrote:
> Sec proxy data buffer is 60 bytes with the last of the registers
> indicating transmission completion. This however poses a bit of a
> challenge.
>
> The backing memory for sec_proxy is regular memory, and all sec proxy
> does is to trigger a burst of all 60 bytes of data over to the target
> thread backing ring accelerator. It doesn't do a memory scrub when
> it moves data out in the burst. When we transmit multiple messages,
> remnants of previous message is also transmitted which results in
> some random data being set in TISCI fields of messages that have been
> expanded forward.
>
> The entire concept of backward compatibility hinges on the fact that
> the unused message fields remain 0x0 allowing for 0x0 value to be
> specially considered when backward compatibility of message extension
> is done.
>
> So, instead of just writing the completion register, we continue
> to fill the message buffer up with 0x0 (note: for partial message
> involving completion, we already do this).
>
> This allows us to scale and introduce ABI changes back also work with
> other boot stages that may have left data in the internal memory.
>
> While at this, drop the unused accessor function.
>
> Fixes: f9aa41023bd9 ("mailbox: Introduce K3 Secure Proxy Driver")
> Signed-off-by: Nishanth Menon <n...@ti.com>Applied to u-boot/master, thanks! -- Tom
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