Re: [PATCH v3 35/36] net/wan: make FSL_UCC_HDLC explicitly depend on PPC32

On Mon, Nov 4, 2019 at 2:39 AM Rasmus Villemoes
[off-list ref] wrote:

On 01/11/2019 23.31, Leo Li wrote:

quoted

quoted

-----Original Message-----
From: Christophe Leroy <redacted>
Sent: Friday, November 1, 2019 11:30 AM
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>; Qiang Zhao
[off-list ref]; Leo Li [off-list ref]
Cc: linuxppc-dev@lists.ozlabs.org; linux-arm-kernel@lists.infradead.org;
linux-kernel@vger.kernel.org; Scott Wood [off-list ref];
netdev@vger.kernel.org
Subject: Re: [PATCH v3 35/36] net/wan: make FSL_UCC_HDLC explicitly
depend on PPC32



Le 01/11/2019 à 13:42, Rasmus Villemoes a écrit :

quoted

Currently, FSL_UCC_HDLC depends on QUICC_ENGINE, which in turn

depends

quoted

on PPC32. As preparation for removing the latter and thus allowing the
core QE code to be built for other architectures, make FSL_UCC_HDLC
explicitly depend on PPC32.

Is that really powerpc specific ? Can't the ARM QE perform HDLC on UCC ?

I think the driver would build on ARM. Whether it works I don't know. I
know it does not build on 64 bit hosts (see kbuild report for v2,23/23).

The problem for arm64 can be easy to fix.  Actually I don't think it
is neccessarily to be compiled on all architectures except powerpc,
arm and arm64.  I am surprised that you made the core QE code compile
for all architecture(although still have some kbuild warnings)

quoted

No.  Actually the HDLC and TDM are the major reason to integrate a QE on the ARM based Layerscape SoCs.

[citation needed].

I got this message from our marketing team.  Also it is reflected on
marketing materials like
https://www.nxp.com/products/processors-and-microcontrollers/arm-processors/layerscape-communication-process/qoriq-layerscape-1043a-and-1023a-multicore-communications-processors:LS1043A

"The QorIQ LS1043A ... integrated QUICC Engine® for legacy glue-less
HDLC, TDM or Profibus support."

quoted

Since Rasmus doesn't have the hardware to test this feature Qiang Zhao probably can help verify the functionality of TDM and we can drop this patch.

No, this patch cannot be dropped. Please see the kbuild complaints for
v2,23/23 about use of IS_ERR_VALUE on not-sizeof(long) entities. I see
kbuild has complained about the same thing for v3 since apparently the
same thing appears in ucc_slow.c. So I'll fix that.

When I made this comment I didn't notice you have removed all the
architectural dependencies for CONFIG_QUICC_ENGINE.  If the
QUICC_ENGINE is only buidable on powerpc, arm and arm64, this change
will not be needed.

BTW, I'm not sure if it is a good idea to make it selectable on these
unrelavent architectures.  Real architectural dependencies and
COMPILE_TEST dependency will be better if we really want to test the
buildability on other platforms.

Regards,
Leo