[U-Boot] [PATCH] vexpress64: compile Juno PCIe conditionally

[Ryan Harkin]

On 13 November 2015 at 13:39, Ryan Harkin <ryan.harkin at linaro.org> wrote:
> [trying again with Linus on the to: list]
>
> Hi Linus,
>
> Tom asked for a small change to your patch.  Would mind having a look
> and re-working?
>
> Thanks,
> Ryan.
>
> On 21 October 2015 at 14:16, Ryan Harkin <ryan.harkin at linaro.org> wrote:
>> On 21 October 2015 at 13:50, Tom Rini <trini at konsulko.com> wrote:
>>> On Wed, Oct 21, 2015 at 12:00:03PM +0100, Ryan Harkin wrote:
>>>> On 20 October 2015 at 16:38, Tom Rini <trini at konsulko.com> wrote:
>>>>
>>>> > On Tue, Oct 20, 2015 at 08:05:40AM +0200, Linus Walleij wrote:
>>>> >
>>>> > > Only compile in PCIe support if the board really uses it. Provide
>>>> > > a stub for the init function if e.g. FVP is being built.
>>>> > >
>>>> > > Cc: Liviu Dudau <Liviu.Dudau at foss.arm.com>
>>>> > > Cc: Ryan Harkin <ryan.harkin at linaro.org>
>>>> > > Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
>>>> > > ---
>>>> > >  board/armltd/vexpress64/Makefile | 3 ++-
>>>> > >  board/armltd/vexpress64/pcie.c   | 2 --
>>>> > >  board/armltd/vexpress64/pcie.h   | 4 ++++
>>>> > >  3 files changed, 6 insertions(+), 3 deletions(-)
>>>> > >
>>>> > > diff --git a/board/armltd/vexpress64/Makefile
>>>> > b/board/armltd/vexpress64/Makefile
>>>> > > index a35db401b684..b4391a71249a 100644
>>>> > > --- a/board/armltd/vexpress64/Makefile
>>>> > > +++ b/board/armltd/vexpress64/Makefile
>>>> > > @@ -5,4 +5,5 @@
>>>> > >  # SPDX-License-Identifier:   GPL-2.0+
>>>> > >  #
>>>> > >
>>>> > > -obj-y        := vexpress64.o pcie.o
>>>> > > +obj-y        := vexpress64.o
>>>> > > +obj-$(CONFIG_TARGET_VEXPRESS64_JUNO) += pcie.o
>>>> > > diff --git a/board/armltd/vexpress64/pcie.c
>>>> > b/board/armltd/vexpress64/pcie.c
>>>> > > index 7b999e8ef40b..311c4500e3ff 100644
>>>> > > --- a/board/armltd/vexpress64/pcie.c
>>>> > > +++ b/board/armltd/vexpress64/pcie.c
>>>> > > @@ -191,7 +191,5 @@ void xr3pci_init(void)
>>>> > >
>>>> > >  void vexpress64_pcie_init(void)
>>>> > >  {
>>>> > > -#ifdef CONFIG_TARGET_VEXPRESS64_JUNO
>>>> > >       xr3pci_init();
>>>> > > -#endif
>>>> > >  }
>>>> > > diff --git a/board/armltd/vexpress64/pcie.h
>>>> > b/board/armltd/vexpress64/pcie.h
>>>> > > index 14642f4f5c43..55b276d6af11 100644
>>>> > > --- a/board/armltd/vexpress64/pcie.h
>>>> > > +++ b/board/armltd/vexpress64/pcie.h
>>>> > > @@ -1,6 +1,10 @@
>>>> > >  #ifndef __VEXPRESS64_PCIE_H__
>>>> > >  #define __VEXPRESS64_PCIE_H__
>>>> > >
>>>> > > +#ifdef CONFIG_TARGET_VEXPRESS64_JUNO
>>>> > >  void vexpress64_pcie_init(void);
>>>> > > +#else
>>>> > > +static inline void vexpress64_pcie_init(void) {}
>>>> > > +#endif
>>>> > >
>>>> > >  #endif /* __VEXPRESS64_PCIE_H__ */
>>>> >
>>>> > Alright, so the versatile platform makes life fun at times.
>>>>
>>>>
>>>> This comes back to the refactoring thread we had recently...
>>>>
>>>>
>>>>
>>>> >   First, my
>>>> > preference is for weak functions (and I _think_ the linker ends up being
>>>> > smart enough about them to optimize things away, if not, arrg).  Second,
>>>> > the question I have is, is this xr3pci_init() bit really a Juno thing or
>>>> > a baseboard thing (I assume no)
>>>>
>>>>
>>>> It's sort-of the same thing on Juno.  Juno has a baseboard and SoC in one
>>>> build, unlike the previous 32-bit Versatile Express motherboard that takes
>>>> core tiles with different cores on it.
>>>>
>>>> Juno R0 has the PCIe controller, but it doesn't work.  So the code is safe
>>>> to run at this level.  Juno R1 has the controller and it works.
>>>>
>>>> or a going to be the same on the next
>>>> > Cortex-Asomething module thing?
>>>>
>>>>
>>>> Juno R2 will have the PCIe controller too and it should hopefully work.
>>>
>>> But it will also be the A52.  Or no, the A72?  Or can't say..
>>>
>>
>> If I knew the answer, "can't say" would probably be the official line.
>> But I haven't been told of any plans to change the cores, so I am
>> assuming the next Juno respin will be A57/A53 big.LITTLE.  Just like
>> we have now but with fixes.
>>
>>
>>>> But this controller is not Cortex-Asomething related.  Another vendor could
>>>> put the same IP block on their board, of course.
>>>
>>> Right, but it wouldn't be under board/armltd/vexpress64/ either..
>>>
>>>> FVP models don't have it and other ARM platforms won't necessarily have it.
>>>>
>>>> Does that help?!
>>>
>>> Yes, thanks.  I think it's just a style thing then.  We don't do a lot
>>> of static inline nop functions, we do __weak functions in the main file
>>> (and comment about what it should be doing in a real function) and then
>>> provide the strong version in another file.  So just the pcie.h part
>>> needs changing then.
>>

I'm not familiar with how __weak functions work, but reading Tom's
advice and grepping the code leads me to the diff below.  Tom, is this
what you were looking for?

diff --git a/board/armltd/vexpress64/Makefile b/board/armltd/vexpress64/Makefile
index a35db40..b4391a7 100644
--- a/board/armltd/vexpress64/Makefile
+++ b/board/armltd/vexpress64/Makefile
@@ -5,4 +5,5 @@
 # SPDX-License-Identifier:    GPL-2.0+
 #

-obj-y    := vexpress64.o pcie.o
+obj-y    := vexpress64.o
+obj-$(CONFIG_TARGET_VEXPRESS64_JUNO)    += pcie.o
diff --git a/board/armltd/vexpress64/pcie.c b/board/armltd/vexpress64/pcie.c
index 7b999e8..311c450 100644
--- a/board/armltd/vexpress64/pcie.c
+++ b/board/armltd/vexpress64/pcie.c
@@ -191,7 +191,5 @@ void xr3pci_init(void)

 void vexpress64_pcie_init(void)
 {
-#ifdef CONFIG_TARGET_VEXPRESS64_JUNO
     xr3pci_init();
-#endif
 }
diff --git a/board/armltd/vexpress64/vexpress64.c
b/board/armltd/vexpress64/vexpress64.c
index f4e8084..09a3166 100644
--- a/board/armltd/vexpress64/vexpress64.c
+++ b/board/armltd/vexpress64/vexpress64.c
@@ -28,6 +28,8 @@ U_BOOT_DEVICE(vexpress_serials) = {
        .platdata = &serial_platdata,
 };

+__weak void vexpress64_pcie_init(void) {}
+
 int board_init(void)
 {
        vexpress64_pcie_init();

-- 


Linus, you've indicated that you didn't want to make this change but
are OK with me taking it over.  In my tree, I've just squashed my
patch into yours.  Would you like me to remove your author and
signed-off-by or would you prefer me to post a fixed up version of
your patch?

Cheers,
Ryan.