Hi Marc,

Thanks for the review.

On 03/01/2016 10:34 AM, Ramesh Shanmugasundaram wrote:

quoted

This patch adds support for the CAN FD controller found in Renesas
R-Car SoCs. The controller operates in CAN FD mode by default. Two
test modes are available and can be enabled by the
"rcar_canfd.testmode" module parameter. Refer to Documentation/kernel-

parameters.txt.

Is the channel loopback mode configurable per channel? If so, please
remove the module parameter and make use of CAN_CTRLMODE_LOOPBACK to
configure it.

The loopback setting is not truly a per channel attribute. It requires touching Rx rules which can be done only when the controller's global state is reset (during probe). CAN_CTRLMODE_LOOPBACK config option is possible only through .ndo_open of that channel but the global controller state needs to be operational by this time. As it is a global attribute & for the above reason, I choose the module option.

quoted

CAN FD mode supports both Classical CAN & CAN FD frame formats. The
controller supports ISO 11898-1:2015 CAN FD format only.

This controller supports two channels and the driver can enable either
or both of the channels.

Driver uses Rx FIFOs (one per channel) for reception & Common FIFOs
(one per channel) for transmission. Rx filter rules are configured to
the minimum (one per channel) and it accepts Standard, Extended, Data
& Remote Frame combinations.

I see no locking for the tx-path.

 
I am not sure why locking is needed in tx-path? 
However, looking at it again, I should move the incrementing of head after the "sts" handing to be apt. What do you think?

Thanks,
Ramesh