of_serial vs legacy serial support with powerpc arch on 405

of_serial vs legacy serial support with powerpc arch on 405

[John Linn]

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I've searched and found some threads, but it's still not clear to me.
I'm working on 405 with powerpc and trying to get UART550 working.

 

I know that I need speed, freq, and reg-shift properties in the device
tree and I have found patches for of_serial.c.

 

I still don't understand when to use of_serial.c (SERIAL_OF_PLATFORM) vs
the legacy support for serial ports.  Is there any docs that I'm not
finding that I should read?

 

I don't see a way to configure in the legacy support, but I'm using
SERIAL_OF and having problems. I don't see the console getting enabled
even though it found the serial port driver.

 

Thanks,

John

 


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Re: of_serial vs legacy serial support with powerpc arch on 405

[Josh Boyer]

On Tue, 11 Mar 2008 09:04:27 -0600
"John Linn" <John.Linn@xilinx.com> wrote:

> I've searched and found some threads, but it's still not clear to me.
> I'm working on 405 with powerpc and trying to get UART550 working.

Walnut works.  So do Halakeau and Kilauea.  Is your serial port
significantly different from those?

> I know that I need speed, freq, and reg-shift properties in the device
> tree and I have found patches for of_serial.c.

Patches for of_serial.c for what?
 
> I still don't understand when to use of_serial.c (SERIAL_OF_PLATFORM) vs
> the legacy support for serial ports.  Is there any docs that I'm not
> finding that I should read?

There are no docs.  At one time, of_serial was declared as the one true
serial driver, but these days either will do.  The benefit of
legacy_serial is that output is enabled earlier in the boot.

> I don't see a way to configure in the legacy support, but I'm using
> SERIAL_OF and having problems. I don't see the console getting enabled
> even though it found the serial port driver.

You need to have CONFIG_PPC_UDBG_16550 set to bring in legacy_serial.

josh

RE: of_serial vs legacy serial support with powerpc arch on 405

[Stephen Neuendorffer]

Josh,

Specifically, we're trying to get console on of_serial, but there
doesn't seem to be any code to register a console, except in
legacy_serial?  But legacy_serial doesn't implement the offsets
necessary for the Xilinx uart16550 cores.  Does it seem reasonable to
add code to of_serial.c to register consoles, or is there something else
we're missing here?

Steve

> -----Original Message-----
> From: =
linuxppc-dev-bounces+stephen.neuendorffer=3Dxilinx.com@ozlabs.org
[mailto:linuxppc-dev-
> bounces+stephen.neuendorffer=3Dxilinx.com@ozlabs.org] On Behalf Of =
Josh
Boyer
> Sent: Tuesday, March 11, 2008 3:03 PM
> To: John Linn
> Cc: linuxppc-dev@ozlabs.org
> Subject: Re: of_serial vs legacy serial support with powerpc arch on
405
>=20
> On Tue, 11 Mar 2008 09:04:27 -0600
> "John Linn" <John.Linn@xilinx.com> wrote:
>=20
> > I've searched and found some threads, but it's still not clear to
me.
> > I'm working on 405 with powerpc and trying to get UART550 working.
>=20
> Walnut works.  So do Halakeau and Kilauea.  Is your serial port
> significantly different from those?
>=20
> > I know that I need speed, freq, and reg-shift properties in the
device
> > tree and I have found patches for of_serial.c.
>=20
> Patches for of_serial.c for what?
>=20
> > I still don't understand when to use of_serial.c
(SERIAL_OF_PLATFORM) vs
> > the legacy support for serial ports.  Is there any docs that I'm not
> > finding that I should read?
>=20
> There are no docs.  At one time, of_serial was declared as the one
true
> serial driver, but these days either will do.  The benefit of
> legacy_serial is that output is enabled earlier in the boot.
>=20
> > I don't see a way to configure in the legacy support, but I'm using
> > SERIAL_OF and having problems. I don't see the console getting
enabled
> > even though it found the serial port driver.
>=20
> You need to have CONFIG_PPC_UDBG_16550 set to bring in legacy_serial.
>=20
> josh
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev

RE: of_serial vs legacy serial support with powerpc arch on 405

[John Linn]

Thanks for the help Josh.  I made some comments in-line.


-----Original Message-----
From: Josh Boyer [mailto:jwboyer@linux.vnet.ibm.com]=20
Sent: Tuesday, March 11, 2008 4:03 PM
To: John Linn
Cc: linuxppc-dev@ozlabs.org
Subject: Re: of_serial vs legacy serial support with powerpc arch on 405

On Tue, 11 Mar 2008 09:04:27 -0600
"John Linn" <John.Linn@xilinx.com> wrote:

> I've searched and found some threads, but it's still not clear to me.
> I'm working on 405 with powerpc and trying to get UART550 working.

Walnut works.  So do Halakeau and Kilauea.  Is your serial port
significantly different from those?

>> Requires a shift as the regs are farther apart.

> I know that I need speed, freq, and reg-shift properties in the device
> tree and I have found patches for of_serial.c.

Patches for of_serial.c for what?

>> There was a patch to correct where the spd was assumed to be in the=20
>> device tree and it would bomb out if it wasn't. I was thinking there
was
>> a patch for the reg-shift value also.
=20
> I still don't understand when to use of_serial.c (SERIAL_OF_PLATFORM)
vs
> the legacy support for serial ports.  Is there any docs that I'm not
> finding that I should read?

There are no docs.  At one time, of_serial was declared as the one true
serial driver, but these days either will do.  The benefit of
legacy_serial is that output is enabled earlier in the boot.

> I don't see a way to configure in the legacy support, but I'm using
> SERIAL_OF and having problems. I don't see the console getting enabled
> even though it found the serial port driver.

You need to have CONFIG_PPC_UDBG_16550 set to bring in legacy_serial.

>> Thanks got it working with some mods.

josh