[Buildroot] [PATCH v3 1/5] arm-trusted-firmware: simplify release dir path

[Gary Bisson <gary.bisson@boundarydevices.com>]

Hi Luca,

On Fri, May 04, 2018 at 03:46:06PM +0200, Luca Ceresoli wrote:
> Hi Gary,
> 
> On 04/05/2018 09:14, Gary Bisson wrote:
> > Hi Luca,
> > 
> > On Thu, May 03, 2018 at 06:23:33PM +0200, Luca Ceresoli wrote:
> >> The path to the binary images is very long. Since we are about to make
> >> a larger use of it, let's use a variable to make it somewhat shorter.
> >>
> >> Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
> >>
> >> ---
> >> Changes v2 -> v3: none.
> >> Changes v1 -> v2: none.
> >> ---
> >>  boot/arm-trusted-firmware/arm-trusted-firmware.mk | 3 ++-
> >>  1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/boot/arm-trusted-firmware/arm-trusted-firmware.mk b/boot/arm-trusted-firmware/arm-trusted-firmware.mk
> >> index 4bac916e3108..212bb5049f2b 100644
> >> --- a/boot/arm-trusted-firmware/arm-trusted-firmware.mk
> >> +++ b/boot/arm-trusted-firmware/arm-trusted-firmware.mk
> >> @@ -25,6 +25,7 @@ endif
> >>  ARM_TRUSTED_FIRMWARE_INSTALL_IMAGES = YES
> >>  
> >>  ARM_TRUSTED_FIRMWARE_PLATFORM = $(call qstrip,$(BR2_TARGET_ARM_TRUSTED_FIRMWARE_PLATFORM))
> >> +ARM_TRUSTED_FIRMWARE_IMG_DIR = $(@D)/build/$(ARM_TRUSTED_FIRMWARE_PLATFORM)/release
> >>  
> >>  ARM_TRUSTED_FIRMWARE_MAKE_OPTS += \
> >>  	CROSS_COMPILE="$(TARGET_CROSS)" \
> >> @@ -82,7 +83,7 @@ define ARM_TRUSTED_FIRMWARE_BUILD_CMDS
> >>  endef
> >>  
> >>  define ARM_TRUSTED_FIRMWARE_INSTALL_IMAGES_CMDS
> >> -	cp -dpf $(@D)/build/$(ARM_TRUSTED_FIRMWARE_PLATFORM)/release/*.bin $(BINARIES_DIR)/
> >> +	cp -dpf $(ARM_TRUSTED_FIRMWARE_IMG_DIR)/*.bin $(BINARIES_DIR)/
> > 
> > Actually the release folder isn't always in that directory. For
> > instance, the tegra platform requires another TARGET_SOC variable and
> > the bin files are under
> > build/$(ARM_TRUSTED_FIRMWARE_PLATFORM)/$(TARGET_SOC)/release/*.bin.
> > https://github.com/ARM-software/arm-trusted-firmware/blob/master/docs/plat/nvidia-tegra.rst
> > 
> > Don't get me wrong, your patch doesn't break anything, I just wanted to
> > inform you of that tegra case. My quick (and dirty) fix was to do a the
> > following:
> > find $(@D)/build/$(ARM_TRUSTED_FIRMWARE_PLATFORM) -name "*.bin" -exec cp -dpf {} $(BINARIES_DIR)/ \;
> 
> So if I understood correctly the current .mk file would not work for
> tegra, both with and without my patch.

Exactly.

> Also your 'find' solution cannot work from ARM_TRUSTED_FIRMWARE_IMG_DIR
> as I defined it, because of the added '/release' dir.

Yes, that is why I bring it up here. I planned on sending that 'find'
trick as a RFC although I don't expect that solution to be accepted.

> > But if you want to have a generic ARM_TRUSTED_FIRMWARE_IMG_DIR I guess
> > the solution is to have an optional ARM_TRUSTED_FIRMWARE_TARGET_SOC
> > variable added to arm-trusted-firmware.mk.
> 
> Well, using 'find' would be a simpler trick without clobbering the
> Config.in space. But then in patch 2 I use ARM_TRUSTED_FIRMWARE_IMG_DIR
> in several places, and using plain 'find' there would introduce
> additional problems.

Yes. And to be honest, there's no real Tegra support in Buildroot right
now so I'm not against your series. Just wanted people to know about
that case.

> Do you think there is a way to extract the TARGET_SOC value
> automatically, in order to avoid yet another Config.in variable in ATF?
> I'm afraid I'm not optimistic on this...

Me neither, I don't see a way to extract the TARGET_SOC.

> An alternative, under the assumption that only one *.bin file is
> generated, is: find that file wherever it is, and use the path to it
> everywhere to reference to it. Pseudocode (perhaps better done in pure
> make):
> 
>   ARM_TRUSTED_FIRMWARE_IMG = $(dir $(shell \
>     find $(@D)/build/$(ARM_TRUSTED_FIRMWARE_PLATFORM) -name "*.bin" | \
>     head -n1))
> 
> This would avoid any additional variables and give us the path of the
> binary. Do you think it could work?

Yes I think that would work but I'm not fond of that 'find' command in
the first place. In my opinion having a TARGET_SOC variable, even if
empty for most platforms, is a more elegant solution.

But, I've CC'd Sergey to help in that decision process since he's the
one maintaining the package.

Regards,
Gary