On Tuesday 27 May 2014 14:13:32 Daniel Thompson wrote:

On 26/05/14 14:39, Arnd Bergmann wrote:

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diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index eab8ecb..4c8d7db 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug

@@ -842,7 +842,18 @@ choice
 
      config DEBUG_LL_UART_NONE
              bool "No low-level debugging UART"
-             depends on !ARCH_MULTIPLATFORM
+             depends on ARCH_AT91 || \
+                     ARCH_CLPS711X || \
+                     ARCH_FOOTBRIDGE || \
+                     ARCH_KS8695 || \
+                     ARCH_NETX || \
+                     ARCH_OMAP1 || \
+                     ARCH_SA1100 || \
+                     ARCH_S3C24XX || \
+                     ARCH_S3C64XX || \
+                     ARCH_S5P64X0 || \
+                     ARCH_S5PC100 || \
+                     ARCH_S5PV210
              help
                Say Y here if your platform doesn't provide a UART option
                above. This relies on your platform choosing the right UART

ARCH_S3C24XX has been moved over in linux-next to use debug/s3c24xx.S.
A few others will likely move soon (AT91, CLPS711x, S5PV210), as the
platforms get moved to ARCH_MULTIPLATFORM.

The list in my patch came from:

sundance$ find arch/arm -name "debug-macro.S"
arch/arm/mach-at91/include/mach/debug-macro.S
arch/arm/mach-clps711x/include/mach/debug-macro.S
arch/arm/mach-footbridge/include/mach/debug-macro.S
arch/arm/mach-ks8695/include/mach/debug-macro.S
arch/arm/mach-netx/include/mach/debug-macro.S
arch/arm/mach-omap1/include/mach/debug-macro.S
arch/arm/mach-s3c64xx/include/mach/debug-macro.S
arch/arm/mach-s5p64x0/include/mach/debug-macro.S
arch/arm/mach-s5pc100/include/mach/debug-macro.S
arch/arm/mach-s5pv210/include/mach/debug-macro.S
arch/arm/mach-sa1100/include/mach/debug-macro.S

In other words this patch lists of all platforms where
DEBUG_LL_UART_NONE should not result in failure to compile the kernel.

I see the same list, this is only half the story though.

This list doesn't seem to have changed in linux-next.

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As an alternative to your patch, we could decide to move the remaining
files as well.

Follow-up: I also noticed that AT91, CLPS711X, FOOTBRIDGE and all the SAMSUNG
platforms already have an entry in the list, so DEBUG_LL_UART_NONE is redundant
for them. The below change should be enough.

For AT91 this is actually better because the old AT91X40 support doesn't
have working DEBUG_LL support. This gets handled correctly by 
AT91_DEBUG_LL_DBGU0/AT91_DEBUG_LL_DBGU1, but not DEBUG_LL_UART_NONE.

I'm very happy to update my patch to follow this one. However since it
will render the corresponding debug-macro.S unreachable by KBuild I like
to nuke the file as well. Good idea?

No. See the description under config DEBUG_LL_UART_NONE:

                  Say Y here if your platform doesn't provide a UART option
                  above. This relies on your platform choosing the right UART
                  definition internally in order for low-level debugging to
                  work.

The platforms I listed do have "a UART option above", e.g.

        config AT91_DEBUG_LL_DBGU0
                bool "Kernel low-level debugging on rm9200, 9260/9g20, 9261/9g10 and 9rl"
                depends on HAVE_AT91_DBGU0

Most of the platforms that have an option like this put the file into
include/debug, as is required for ARCH_MULTIPLATFORM. The ones that are
not converted to ARCH_MULTIPLATFORM can have it in either place, see

config DEBUG_LL_INCLUDE
        string
        default "debug/8250.S" if DEBUG_LL_UART_8250 || DEBUG_UART_8250
        default "debug/pl01x.S" if DEBUG_LL_UART_PL01X || DEBUG_UART_PL01X
	...
        default "debug/zynq.S" if DEBUG_ZYNQ_UART0 || DEBUG_ZYNQ_UART1
        default "mach/debug-macro.S"

Anything that is not explicitly listed under DEBUG_LL_INCLUDE will default
to "mach/debug-macro.S", and the list does not (have to) match the choice
statements in "Kernel low-level debugging port".

	Arnd