[GSoC] CAN SJA1000

jinyang.sia at gmail.com jinyang.sia at gmail.com
Mon Sep 16 23:53:48 UTC 2013

Hi, all

Thanks for your advices. Actually, I want to continue this project after the GSoC2013. I think there are still lots of work we need to do in the future, such as adding some more effective tests for PCI-CAN device, investing into QEMU mainline and also some others that Pavel Pisa suggested.

Jin Yang

jinyang.sia at gmail.com

From: Gedare Bloom
Date: 2013-09-16 20:57
To: jinyang.sia at gmail.com
CC: Pavel Pisa; Rempel, Cynthia; Chris Johns; RTEMS Devel
Subject: Re: [GSoC] CAN SJA1000
Jin Yang, you should incorporate these notes and suggestions to your
project's wrap-up / summary descriptions. If you are interested in
continuing after GSoC with this project I think this will be a good
direction to head.

On Sun, Sep 15, 2013 at 3:56 PM, Pavel Pisa <ppisa4lists at pikron.com> wrote:
> Hello Jin Yang and all others,
> congratulation to achieving the main goal.
> I have read your instructions and build sucesfull
> the QEMU on AMD64 Debian Wheezy.
> I have run the compiled QEMU with 64-bit 3.2.x kernel
> used on a host and guest side of the QEMU.
> I have included board integration into LinCAN driver
> http://sourceforge.net/p/ortcan/lincan/ci/master/tree/lincan/src/pcisja1000mm.c
> and run successfully LinCAN test tools on the guest side
> against your SJA1000 HW emulation. I have connected host
> side to the virtual SocketCAN bus and used OrtCAN qCANalyzer
> on the host side
>   http://ortcan.sourceforge.net/qcanalyzer/
> I have not found any problems during this test.
> But tat is quit simple test and it would worth to
> try some more demanding testing. But as you know
> we are not fast (unfortuantelly) in many cases so
> it would take some time. Anyway it worth to run
> our CAN Benchmarks to torture code and clean possible
> bugs
>   http://rtime.felk.cvut.cz/can/
> By the way, we have included actual MPC5200 RTEMS CAN
> driver into our benchmarks this summer and results are
> quite in favor for RTEMS but that is partially caused
> by dummy implementation of CAN gateway user on RTEMS
> for testing. But that worths separate e-mail as we
> finish the work.
> As for actual Jin Yang's QEMU CAN code, I think that
> it is valuable achievement for GSoC project and if
> stability is confirmed by testing, it is good base
> for RTEMS CAN infrastructure development.
> On the other hand, for long term sustainability
> it is required to invest into inclusion of code
> to the QEMU mainline. This requires to port code
> to the actual QEMU git version. I do not know
> how big amount it means because QEMU is fast
> mowing target. It may be above GSoC project contract
> size. But it really worth to be done.
> As for the code review, I think that there is too
> much CAN specific code push into generic qemu-char.c
> file
>   qemu-jin-yang/qemu-char.c
> The registration in actual QEMU git version seems to be more
> modular
>     register_char_driver_qapi("parallel", CHARDEV_BACKEND_KIND_PARALLEL,
>                               qemu_chr_parse_parallel);
> The all SocketCAN specific code has to be moved to other
> file and there must be mechanism to disable build of that
> code
> qemu-jin-yang/qemu-char.c
> +#include <linux/can.h>
> +#include <linux/can/raw.h>
> The reason is that SocketCAN is Linux specific and that part
> of the code included in the common QEMU infrastructure
> would made it non-portable.
> As for the actual can controller emulation, it is/or can be
> made fully portable to all host systems and for all target
> configurations which support PCI
>   qemu-jin-yang/hw/can-pci.c
> It would worth to separate SJA1000 part of the code from
> PCI mapping to allows use SJA1000 emulator even on non-PCI
> platforms. It would worth even to allows to use SJA1000
> emulator with different PCI cards mapping. The most of real
> CAN interface cards have more PCI regions/BARs and actual CAN
> chips are mapped to region 1 or 2. Region 0 is usually used
> to control PCI bridge part of the card. Use of generic PCI
> bridge chips usually means that some interrupt configuration
> is required in this bridge control area.
> But these two are not high priority for now.
> As for actual SJA1000 chip emulation, I would prefer personally
> if the register bit masks are not hardcoded by numbers but
> if some better readable constants are used. I.e.
> http://sourceforge.net/p/ortcan/lincan/ci/master/tree/lincan/include/sja1000p.h
> But again that can be done later.
> Best wishes,
>              Pavel Pisa
> On Sunday 15 of September 2013 10:16:39 jinyang.sia at gmail.com wrote:
>> Hi,
>> I just update the http://wiki.rtems.org/wiki/index.php/Qemu_simulations
>> remove some unecessary data and add some new information. Some of them is
>> not complete. However I don't know how to upload pictures to the site?
>> Thanks,
>> Jin Yang
>> jinyang.sia at gmail.com
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