[PATCH] drivers/misc: add Aspeed LPC snoop driver

Benjamin Herrenschmidt benh at kernel.crashing.org
Tue Jun 13 09:05:56 AEST 2017

On Tue, 2017-06-13 at 09:04 +1000, Benjamin Herrenschmidt wrote:
> On Fri, 2017-06-09 at 15:16 -0700, Rick Altherr wrote:
> > I've only seen the Aspeed eSPI hardware.  It implements demux of the
> > eSPI channels in the hardware and provides separate DMA descriptors
> > for each.  It looks nothing like LPC at any level.
> Sort of... it does have a kind of memory mapped IO channel which
> *could* be aliased to the LPC IO space though afaik, Aspeed just
> aliases it to their internal bus which is a recipe for disaster when it
> comes to security, so one should just disable it.
> It's unfortunate, I don't see how you can access things like the legacy
> UART, RTC etc... via eSPI. It looks like yet another crackpot invented
> for SMM BIOS to get in the way and emulate everything. Yuck.

That said I may just not be understanding the spec completely ... I
noticed in the SuperIO bits in the aspeed doc that there are fixed
addresses for some devices on eSPI so ... including the UART.


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