[U-Boot] CAN console

[U-Boot] CAN console

[Matthias Weißer]

Hi

I have a device here which has only a CAN interface to the
outside world. I am currently thinking about implementing
a "serial" driver using the CAN controller.

Is there any chance to get this accepted in the public u-boot
tree?

A special program on the PC side would be needed to translate
the CAN messages back to a serial stream and vice versa and
make it available to a terminal program. But thats another story.

Regards,
Matthias Wei?er

[U-Boot] CAN console

[Mike Frysinger]

On Monday 26 October 2009 04:20:02 Matthias Wei?er wrote:
> I have a device here which has only a CAN interface to the
> outside world. I am currently thinking about implementing
> a "serial" driver using the CAN controller.
> 
> Is there any chance to get this accepted in the public u-boot
> tree?

someone just posted a port of the Linux CAN framework.  if your driver used 
that to implement a serial layer, i dont see why it wouldnt be accepted.
-mike
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[U-Boot] CAN console

[Matthias Weißer]

Mike Frysinger schrieb:
> On Monday 26 October 2009 04:20:02 Matthias Wei?er wrote:
>> I have a device here which has only a CAN interface to the
>> outside world. I am currently thinking about implementing
>> a "serial" driver using the CAN controller.
>>
>> Is there any chance to get this accepted in the public u-boot
>> tree?
> 
> someone just posted a port of the Linux CAN framework.  if your driver used 
> that to implement a serial layer, i dont see why it wouldnt be accepted.
> -mike

Well, that means that I have to implement a full functional CAN driver
and then additionally add a serial driver using the (completely new) CAN
framework. My idea was that I just add a serial_ccan.c to drivers/serial.

Matthias Wei?er

[U-Boot] CAN console

[Mike Frysinger]

On Monday 26 October 2009 07:09:03 Matthias Wei?er wrote:
> Mike Frysinger schrieb:
> > On Monday 26 October 2009 04:20:02 Matthias Wei?er wrote:
> >> I have a device here which has only a CAN interface to the
> >> outside world. I am currently thinking about implementing
> >> a "serial" driver using the CAN controller.
> >>
> >> Is there any chance to get this accepted in the public u-boot
> >> tree?
> >
> > someone just posted a port of the Linux CAN framework.  if your driver
> > used that to implement a serial layer, i dont see why it wouldnt be
> > accepted.
> 
> Well, that means that I have to implement a full functional CAN driver
> and then additionally add a serial driver using the (completely new) CAN
> framework. My idea was that I just add a serial_ccan.c to drivers/serial.

you would rather write a driver that is specific to one CAN hardware ?  
writing it to a common framework would allow every one with a CAN driver to 
use it ...
-mike
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[U-Boot] CAN console

[Matthias Weißer]

Mike Frysinger schrieb:
> you would rather write a driver that is specific to one CAN hardware ?  

In general? No, I wouldn't. I would use a given CAN driver framework 
where I put my CAN driver in.

In this specific case: I think I would, as there is currently no CAN 
framework available in u-boot.

Is there any chance that the stuff posted by miaofng will be available 
in u-boot-next?

> writing it to a common framework would allow every one with a CAN driver to 
> use it ...

Yes. I totally agree here. And if there is a chance that there will be a 
CAN framework in u-boot in not to far future I will write my stuff 
against that.

I think I am not deep enough in u-boot that I will be able to write such 
a framework by myself.

Ragards,
Matthias Wei?er

[U-Boot] CAN console

[Mike Frysinger]

On Monday 26 October 2009 08:20:03 Matthias Wei?er wrote:
> Mike Frysinger schrieb:
> > you would rather write a driver that is specific to one CAN hardware ?
> 
> In general? No, I wouldn't. I would use a given CAN driver framework
> where I put my CAN driver in.
> 
> In this specific case: I think I would, as there is currently no CAN
> framework available in u-boot.

my point was more that a common driver would probably be more likely to be 
accepted, but this leads me to the next point ...

> Is there any chance that the stuff posted by miaofng will be available
> in u-boot-next?

no idea, i'm not the maintainer.  just part of the peanut gallery.
-mike
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[U-Boot] CAN console

[Wolfgang Denk]

Dear =?ISO-8859-15?Q?Matthias_Wei=DFer?=,

In message <4AE593F3.3030608@arcor.de> you wrote:
>
> In this specific case: I think I would, as there is currently no CAN
> framework available in u-boot.

This just means that your implementation requires a two-step approach.
In step 1, implement the framework.

> Is there any chance that the stuff posted by miaofng will be available
> in u-boot-next?

I'm not really sure. As Wolfgang Grandegger already commented, the
implementation is really heavy for a mere boot loader. Sharing code
with Linux is generally a good thing, but it has to fit, too. I'm not
convinced it fits here. Let's see wht the now following discussion
gives. In any case, this is too green for "next". IMHO it would even
bee too green for "staging" if we had something like this (which we
don't have :-)


> Yes. I totally agree here. And if there is a chance that there will be a
> CAN framework in u-boot in not to far future I will write my stuff
> against that.

Do both things at once? The effort saved to re-implement your driver
code against the to-be framwork can be thrown at implementing the
framework in a first step ...

> I think I am not deep enough in u-boot that I will be able to write such
> a framework by myself.

That's only a "not yet", believe me :-)

Best regards,

Wolfgang Denk

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[U-Boot] CAN console

[miaofng]

Wolfgang Denk wrote:
>> Is there any chance that the stuff posted by miaofng will be available
>> in u-boot-next?
>>     
>
> I'm not really sure. As Wolfgang Grandegger already commented, the
> implementation is really heavy for a mere boot loader. Sharing code
> with Linux is generally a good thing, but it has to fit, too. I'm not
> convinced it fits here. Let's see wht the now following discussion
> gives. In any case, this is too green for "next". IMHO it would even
> bee too green for "staging" if we had something like this (which we
> don't have :-)
>
>
>   
In fact it's not so heavy, it is  not socket can architecture based!!!
I copied some of linux socket can based  ->driver part<-  of codes and 
added a small wrapped layer(by myself)
only because i am too lazy to rewrite the sja1000 driver.

For blocked or unblocked access problem, it does support both.
To me, i agree mike's view if i write the sja1000 driver from scratch:)

[U-Boot] CAN console

[Wolfgang Grandegger]

Mike Frysinger wrote:
> On Monday 26 October 2009 07:09:03 Matthias Wei?er wrote:
>> Mike Frysinger schrieb:
>>> On Monday 26 October 2009 04:20:02 Matthias Wei?er wrote:
>>>> I have a device here which has only a CAN interface to the
>>>> outside world. I am currently thinking about implementing
>>>> a "serial" driver using the CAN controller.
>>>>
>>>> Is there any chance to get this accepted in the public u-boot
>>>> tree?
>>> someone just posted a port of the Linux CAN framework.  if your driver
>>> used that to implement a serial layer, i dont see why it wouldnt be
>>> accepted.
>> Well, that means that I have to implement a full functional CAN driver
>> and then additionally add a serial driver using the (completely new) CAN
>> framework. My idea was that I just add a serial_ccan.c to drivers/serial.
> 
> you would rather write a driver that is specific to one CAN hardware ?  
> writing it to a common framework would allow every one with a CAN driver to 
> use it ...

There are many simple USB CAN devices which are operated through the tty
interface. See

  http://prdownload.berlios.de/socketcan/SLCAN-API.pdf


Wolfgang.

[U-Boot] CAN console

[Wolfgang Grandegger]

Matthias Wei?er wrote:
> Hi
> 
> I have a device here which has only a CAN interface to the
> outside world. I am currently thinking about implementing
> a "serial" driver using the CAN controller.

OK, a dedicated CAN driver would make more sense.

> Is there any chance to get this accepted in the public u-boot
> tree?

I think yes, if it does not mis-use U-BOOT

> A special program on the PC side would be needed to translate
> the CAN messages back to a serial stream and vice versa and
> make it available to a terminal program. But thats another story.

Netconsole could do the job, but that would require to run IP over CAN.

Wolfgang.