[U-Boot-Users] Porting UBoot without UART

[U-Boot-Users] Porting UBoot without UART

[Shawn Jin]

Hi,

We're using some emulation box to develop our SoC. Somehow the UART
will the last component available for firmware development. Without
UART, it's very hard to debug UBoot. Can we "easily" drive a car
without eyes?

But it's not impossible to do that. My first thought about porting
UBoot under this circumstance is to disable the serial driver in UBoot
and to redirect all printf to a fixed memory area, just as what a
circular log buffer does. I'm wondering how much workload this will
be. Is this kind of mechasim already existent in UBoot?

Thank you for your comments.
-Shawn.

[U-Boot-Users] Porting UBoot without UART

[Ladislav Michl]

On Tue, Feb 22, 2005 at 11:21:01AM -0800, Shawn Jin wrote:
> My first thought about porting UBoot under this circumstance is to
> disable the serial driver in UBoot and to redirect all printf to a
> fixed memory area, just as what a circular log buffer does. I'm
> wondering how much workload this will be. Is this kind of mechasim
> already existent in UBoot?

Provide our own console functions. See common/console.c and
common/devices.c how it is initialized and used.

Best regards,
	ladis

[U-Boot-Users] Porting UBoot without UART

[Wolfgang Denk]

In message <c3d0340b0502221121c489be4@mail.gmail.com> you wrote:
> 
> We're using some emulation box to develop our SoC. Somehow the UART
> will the last component available for firmware development. Without

What a major mistake of design...

> UART, it's very hard to debug UBoot. Can we "easily" drive a car
> without eyes?

Easily yes, savely no ;-)

> But it's not impossible to do that. My first thought about porting
> UBoot under this circumstance is to disable the serial driver in UBoot
> and to redirect all printf to a fixed memory area, just as what a
> circular log buffer does. I'm wondering how much workload this will
> be. Is this kind of mechasim already existent in UBoot?

There is a log driver, yes.

But U-Boot really assumes that  you  have  a  working  console  port.
Anything else is a major pain in the ...

Best regards,

Wolfgang Denk

-- 
See us @ Embedded World, Nuremberg, Feb 22 - 24,  Hall 10.0 Booth 310
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Nearly everyone is in favor of going  to  heaven  but  too  many  are
hoping  they'll  live  long  enough  to see an easing of the entrance
requirements. Never appeal to a man's "better nature." he  might  not
have one.

[U-Boot-Users] Porting UBoot without UART

[Wolfgang Denk]

In message <20050222194931.GA13447@linux-mips.org> you wrote:
>
> Provide our own console functions. See common/console.c and
> common/devices.c how it is initialized and used.

Note thatt he "devices"  are  intialized  pretty  late  in  the  boot
sequence.  Until  then,  all  of  the  most  of the important console
messages have already beeen printed.

Best regards,

Wolfgang Denk

-- 
See us @ Embedded World, Nuremberg, Feb 22 - 24,  Hall 10.0 Booth 310
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Emotions are alien to me.  I'm a scientist.
	-- Spock, "This Side of Paradise", stardate 3417.3

[U-Boot-Users] Porting UBoot without UART

[Grant Likely]

On Thu, 24 Feb 2005 23:39:33 +0100, Wolfgang Denk <wd@denx.de> wrote:
> In message <20050222194931.GA13447@linux-mips.org> you wrote:
> >
> > Provide our own console functions. See common/console.c and
> > common/devices.c how it is initialized and used.
> 
> Note thatt he "devices"  are  intialized  pretty  late  in  the  boot
> sequence.  Until  then,  all  of  the  most  of the important console
> messages have already beeen printed.

[U-Boot-Users] Porting UBoot without UART

[Wolfgang Denk]

Dear Grant,

in message <528646bc0502242240233e0d7f@mail.gmail.com> you wrote:
>
> > > Provide our own console functions. See common/console.c and
> > > common/devices.c how it is initialized and used.
> > 
> > Note thatt he "devices"  are  intialized  pretty  late  in  the  boot
> > sequence.  Until  then,  all  of  the  most  of the important console
> > messages have already beeen printed.
> 
> >From the original post: "We're using some emulation box to develop our
> SoC. Somehow the UART will the last component available for firmware
> development."
> 
> I don't think that is the situation that Shawn is describing.  To me
> it sounded like he is starting firmware development before all of the
> functionality is delivered by the hardware engineers.  I don't think

You are right. Then Ladislav Michl suggested to use  special  console
functions   for   output,   which  works,  but  misses  most  of  the
"interesting" startup messages which  are  printed  long  before  the
device funtions are installed.

> that he is refering to initialization order.  Shawn, could you please
> clarify?

Initialization order plays only a  role  here  as  a  console  device
starts working too late. The native console port is the serial port.

Best regards,

Wolfgang Denk

-- 
See us @ Embedded World, Nuremberg, Feb 22 - 24,  Hall 10.0 Booth 310
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Cleverness and Style have no place in getting a project completed.
                                                  -- Tom Christiansen

[U-Boot-Users] Porting UBoot without UART

[Grant Likely]

On Fri, 25 Feb 2005 08:51:47 +0100, Wolfgang Denk <wd@denx.de> wrote:
> Dear Grant,
> 
> in message <528646bc0502242240233e0d7f@mail.gmail.com> you wrote:
> >
> >
> > >From the original post: "We're using some emulation box to develop our
> > SoC. Somehow the UART will the last component available for firmware
> > development."
> >
> > I don't think that is the situation that Shawn is describing.  To me
> > it sounded like he is starting firmware development before all of the
> > functionality is delivered by the hardware engineers.  I don't think
> 
> You are right. Then Ladislav Michl suggested to use  special  console
> functions   for   output,   which  works,  but  misses  most  of  the
> "interesting" startup messages which  are  printed  long  before  the
> device funtions are installed.
Ahh, thank you.  I had misunderstood what you were talking about.

> > that he is refering to initialization order.  Shawn, could you please
> > clarify?
> 
> Initialization order plays only a  role  here  as  a  console  device
> starts working too late. The native console port is the serial port.
So what needs to be modified to do this?  Create new serial_putc,
_getc, _init etc. functions that send messages to where he needs them?

Cheers,
g.

[U-Boot-Users] Porting UBoot without UART

[Shawn Jin]

> I don't think that is the situation that Shawn is describing.  To me
> it sounded like he is starting firmware development before all of the
> functionality is delivered by the hardware engineers.  I don't think
> that he is refering to initialization order.  Shawn, could you please
> clarify?

Both of you are right. I'm starting firmware development before all
h/w components are ready. H/W folks are pushing to test some of
components before UART is delivered.

Thanks,
-Shawn.

[U-Boot-Users] Porting UBoot without UART

[Grant Likely]

On Fri, 25 Feb 2005 09:55:41 -0800, Shawn Jin <shawnxjin@gmail.com> wrote:
> Both of you are right. I'm starting firmware development before all
> h/w components are ready. H/W folks are pushing to test some of
> components before UART is delivered.

Sounds like some percussive maintenance is needed about the ears of
said H/W folks.  :-P

g.

[U-Boot-Users] Porting UBoot without UART

[Wolfgang Denk]

In message <528646bc0502250800b68e268@mail.gmail.com> you wrote:
>
> > Initialization order plays only a  role  here  as  a  console  device
> > starts working too late. The native console port is the serial port.
> So what needs to be modified to do this?  Create new serial_putc,
> _getc, _init etc. functions that send messages to where he needs them?

Add a working serial port :-)

Best regards,

Wolfgang Denk

-- 
See us @ Embedded World, Nuremberg, Feb 22 - 24,  Hall 10.0 Booth 310
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"Plan to throw one away. You will anyway."
                              - Fred Brooks, "The Mythical Man Month"

[U-Boot-Users] Porting UBoot without UART

[Adam Kent]

Wolfgang Denk wrote:
> In message <528646bc0502250800b68e268@mail.gmail.com> you wrote:
> 
>>>Initialization order plays only a  role  here  as  a  console  device
>>>starts working too late. The native console port is the serial port.
>>
>>So what needs to be modified to do this?  Create new serial_putc,
>>_getc, _init etc. functions that send messages to where he needs them?

For what it's worth, I have recently completed a port of U-Boot to a 
custom board with no serial port in the design.  It does, however, 
have a functioning ethernet port, which we set up to use as a 
netconsole.  Sure, most of the informative boot up messages are 
missed, but to paraphrase Wolfgang, "get a BDI 2000"!  ;)

Good Luck,
Adam Kent