Re: [PATCH 0/6] Integrator devicetree support
From: Arnd Bergmann <hidden>
Date: 2012-08-19 14:05:24
Also in:
linux-arm-kernel
Possibly related (same subject, not in this thread)
- 2012-08-30 · Re: [PATCH 0/6] Integrator devicetree support · Nicolas Pitre <hidden>
- 2012-08-19 · Re: [PATCH 0/6] Integrator devicetree support · Nicolas Pitre <hidden>
- 2012-08-18 · Re: [PATCH 0/6] Integrator devicetree support · Linus Walleij <hidden>
- 2012-08-16 · Re: [PATCH 0/6] Integrator devicetree support · Arnd Bergmann <hidden>
- 2012-08-16 · [PATCH 0/6] Integrator devicetree support · Linus Walleij <hidden>
On Saturday 18 August 2012, Linus Walleij wrote:
Since we already have CONFIG_USE_OF I think CONFIG_USE_ATAGS is more apropriate, but I get the idea.
There is both CONFIG_USE_OF and CONFIG_OF. The former is what a platform selects and it turns on a few other options as well, while the latter is the one that you typically check in #ifdef. We might need both of them for ATAG as well, but I think if we have just one, CONFIG_ATAGS or CONFIG_ATAG would be nicer because it's slightly shorter.
quoted hunk
So it begins like this:diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index e91c7cd..0764ef7 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig@@ -1907,6 +1907,12 @@ endmenu menu "Boot options" +config USE_ATAGS + bool "ATAGS support" + default y + help + Include support for ATAGS-based machine descriptions. + config USE_OF bool "Flattened Device Tree support" select OF@@ -2110,6 +2116,7 @@ config KEXEC config ATAGS_PROC bool "Export atags in procfs" + depends on USE_ATAGS depends on KEXEC default y helpBut then we hit #ifdeffing and compiling out a lot of dangerous stuff in arch/arm/kernel and then I get the creeps. I can try, but I think this is typical Nico territory for example...
We don't have to enclose every single usage of ATAGS with this, but I think it's helpful in platforms that you want to migrate away from ATAG to DT-only. I think we should also use this method in mach-ux500, for instance. Putting MACHINE_START and DT_MACHINE_START inside of CONFIG_ATAG and CONFIG_OF respectively would help ensure that we don't accidentally build support for a board that cannot work. Arnd