Re: [PATCH] can: grcan: Add device driver for GRCAN and GRHCAN cores

[Andreas Larsson <andreas@gaisler.com>]

On 2012-10-11 12:04, Marc Kleine-Budde wrote:
> On 10/04/2012 11:45 AM, Marc Kleine-Budde wrote:
>> Hello,
>>
>> On 10/02/2012 04:38 PM, Andreas Larsson wrote:
>>> This driver supports GRCAN and CRHCAN CAN controllers available in the GRLIB
>>> VHDL IP core library.
>>>
>>> Signed-off-by: Andreas Larsson <andreas@gaisler.com>
>>> ---
>>>   drivers/net/can/Kconfig  |    6 +
>>>   drivers/net/can/Makefile |    1 +
>>>   drivers/net/can/grcan.c  | 1283 ++++++++++++++++++++++++++++++++++++++++++++++
>>>   drivers/net/can/grcan.h  |  273 ++++++++++
>>>   4 files changed, 1563 insertions(+), 0 deletions(-)
>>>   create mode 100644 drivers/net/can/grcan.c
>>>   create mode 100644 drivers/net/can/grcan.h
>>
>> Some general remarks while scrolling though the driver:
>> - please provide a device tree binding documentation
>>    Documentation/devicetree/bindings/net/can/grcan.txt
>>    and add devicetree-discuss@lists.ozlabs.org on Cc
>> - please provide a documentation for the sysfs entries:
>>    Documentation/ABI/testing/sys-XXX-grcan.txt
>> - please implement a NAPI
>> - please include the .h file into the C code,
>>    as the C code is the one and only user of the .h file
>> - please give every macro a GRCAN_ prefix
>
> Your driver should work on little as well as on big endian systems. You
> need probably two implementations of the grcan_{read,write}_reg
> functions, you can take the flexcan driver [1] as an example.

Adding that is easy of course, but that gives the impression of support 
for little endian systems. If the core would be instantiated in a little 
endian fashion in a little endian environment, the DMA accessing parts 
of the hardware would still not work in a little endian system without 
modifications to the hardware design.

 From the driver point of view either way works for me, but I am not 
sure what is best.

Cheers,
Andreas