Randall Spangler c7b11ca7b8 cr50: CCD V1 controls UART access ...

AP and EC UART now use the CCD V1 capabilities to determine when
access is allowed.  Transmit to AP and EC can be toggled independently
from read access to output from those UARTs.

Note that disabling read access disables both transmit and receive.
That is, it's not possible to set a UART where transmit is allowed but
receive isn't.  Why would you want to do that, anyway?

See go/cr50-ccd-wp for more information.

BUG=b:62537474
BRANCH=cr50
TEST=manual with CR50_DEV=1
	ccdoops
	ccdset cr50fullconsole always -> so we can use ccd command for testing
	ccd -> AP RX+TX, EC RX+TX

	ccdset uartecrx unlesslocked
	ccdset uartectx ifopened
	ccdset uartaprx always
	ccdset uartaptx unlesslocked

	ccdunlock
	ccd -> AP RX+TX, EC RX
	ccdlock
	ccd -> AP RX, EC disabled

	ccdoops
	ccdset cr50fullconsole always
	ccd -> AP RX+TX, EC RX+TX
	ccdset uartaprx ifopened
	ccdlock
	ccd -> AP disabled, EC RX

Change-Id: I55db5897bb52cd60658ab221eadf5c59fc86744a
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/595196
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>

2017-08-01 13:01:41 -07:00

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