From: Tom Rini <trini@ti.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [RFC] Two sets of experimental Kconfig patches
Date: Fri, 30 May 2014 13:24:08 -0400 [thread overview]
Message-ID: <20140530172408.GP5836@bill-the-cat> (raw)
In-Reply-To: <20140527163250.4E51.AA925319@jp.panasonic.com>
On Tue, May 27, 2014 at 04:32:50PM +0900, Masahiro Yamada wrote:
> Hi.
>
> I've posted two sets of Kconfig RFC patches: "RFCv2a" and "RFCv2b"
These are all certainly some thought experiments worth pursuing, so
thanks for taking the time.
>
> The difference from v1 is that
> Full U-boot image, SPL and TPL share a single defconfig
> and "make config" is done in one-shot.
>
> This approach dates back to Simon's following comments:
>
> On Thu, 20 Mar 2014 19:15:30 -0700
> Simon Glass <sjg@chromium.org> wrote:
>
> > > But, our situation is a little more complicated.
> > > We need to generate 3 images at most: main image, SPL and TPL.
> > > And each of them can have a different set of CONFIGs.
> > >
> > > For example, we can describe a board header file like this:
> > >
> > > #if defined(CONFIG_TPL_BUILD)
> > > # define CONFIG_FOO 100
> > > #elif defined(CONFIG_SPL_BUILD)
> > > # define CONFIG_FOO 50
> > > #else
> > > # define CONFIG_FOO 10
> > > # define CONFIG_BAR
> > > #endif
> >
> > I wonder if we should drop this, and require that all have the same
> > options? That would involve requiring that board config files are not
> > permitted to use #ifdef CONFIG_SPL or #ifdef CONFIG_TPL.
> >
> > Does that seem like a bad restriction? The advantage is that we only
> > need one defconfig for each board. It seems to me that things are
> > going to get really painful if we have three different configs.
> >
> > Of course, this doesn't preclude #ifdefs in the Makefiles or actual
> > source code, but we already have SPL-specific feature options.
> >
> > I'm not 100% clear on the constraints here.
>
>
> In my opition, this approach might work, but will be painful.
>
> Anyway I just wanted to see what would happen
> if multiple binary images had a single defconfig in common.
>
> We will have to duplicate many configs with CONFIG_SPL_
> and CONFIG_TPL_ prefixes.
>
> For example,
> - CONFIG_SYS_TEXT_BASE (text base for the full image)
> - CONFIG_SPL_TEXT_BASE (text base for SPL)
> - CONFIG_TPL_TEXT_BASE (text base for TPL)
>
> - CONFIG_OF_CONTROL (enables OF control for the full image)
> - CONFIG_SPL_OF_CONTROL (enables OF control for SPL)
> - CONFIG_TPL_OF_CONTROL (enables OF control for TPL)
>
> Probably I will not adopt this approach, but your comments
> are welcome.
The biggest pro I see with this approach is that we don't add more
complication to the process. I often run into "why does make board_name
not work?". However, this will also prevent us from doing some of the
cleanup and restructuring that we need to do. There's too much
duplicated code between SPL/TPL and "normal" U-Boot that we want to fix.
And there are times where a much smaller but more "normal" U-Boot-as-SPL
would be handy. I think in the long run we need to live with this
"problem". Perhaps we can come up with a little Makefile-magic along
the lines of a fullconfig_fooboard rule that would:
mkdir fooboard
if exists fooboard_spl_config, make O=fooboard/spl fooboard_spl_config
if exists fooboard_tpl_config, make O=fooboard/tpl fooboard_tpl_config
make O=fooboard/main fooboard_config
And maybe throw an 'all' in after the config target, maybe not.
> The difference between RFCv2a and RFCv2b is
> how ARCH should be passed to the build system.
>
> In RFCv2a, ARCH is determined by Kconfig.
> We don't have to give it from the command line.
> All defconfig files are stored in configs/ directory.
>
>
> In RFCv2b, ARCH should be given from the command line
> as in Linux Kernel:
> make ARCH=<arch> <board_name>_defconfig
> make ARCH=<arch> CROSS_COMPILE=<gcc_prefix>
> Defconfig files are stored in arch/${ARCH}/configs/ directory.
>
>
> I just tried Linux's way implementation because Stephen mentioned so.
>
> On Thu, 24 Apr 2014 14:36:33 -0600
> Stephen Warren <swarren@wwwdotorg.org> wrote:
>
> > > But in U-Boot, ARCH is not given from the command line.
> > > Which means we cannot know ARCH before the board configuration.
> > > That is why "*_defconfig" files over all architectures should be
> > > gathered into one directory ./configs/.
> > > (The problem is configs/ directory contains about 1200 files!)
> >
> > Perhaps we can change the command-line used to build U-Boot, rather than
> > shoe-horning U-Boot's Kconfig usage to fit that current limitation.
>
>
> But I am not sure if other users are comfortable with giving ARCH=<arch>
> for every configuration and build.
> Your comments are welcome.
So, I know there's a certain number of users that pass ARCH= along
assuming that it's required and just wouldn't notice this particular
change. But as I said in that thread, I really think this is a case
where we can be a little smarter about things, so, well, we ought to
try. It's just a menu choice and I imagine most people won't start with
a totally blank config, even so.
--
Tom
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next prev parent reply other threads:[~2014-05-30 17:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-27 7:32 [U-Boot] [RFC] Two sets of experimental Kconfig patches Masahiro Yamada
2014-05-30 17:24 ` Tom Rini [this message]
2014-06-24 10:24 ` Masahiro Yamada
2014-06-02 4:30 ` Simon Glass
2014-06-24 4:55 ` Masahiro Yamada
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