From: vladimir.murzin@arm•com (Vladimir Murzin)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 0/4] arm/versatile: no-MMU support
Date: Wed, 7 Dec 2016 14:13:03 +0000 [thread overview]
Message-ID: <584818EF.5020905@arm.com> (raw)
In-Reply-To: <a2ab1e0c-d24b-ac8d-fb9a-4ae7271455b9@uclinux.org>
On 07/12/16 13:57, Greg Ungerer wrote:
> Hi Vladimir,
>
> On 07/12/16 19:23, Vladimir Murzin wrote:
>> Hi Greg,
>>
>> On 07/12/16 06:08, Greg Ungerer wrote:
>>> Does the ARM Versatile machine have a maintainer?
>>> I have CC'ed this patch set to those names reported by get_maintainer.
>>> I had no feedback on the first posting of this series back in August.
>>>
>>> The following patches support configuring and building the versatile
>>> machine with a no-MMU kernel.
>>>
>>> There is only a few minor changes required. It was previously possible
>>> in older kernels to build for versatile with CONFIG_MMU disabled, but
>>> the change to devicetree lost that capability. These changes make it
>>> possible again.
>>>
>>> One patch is a fix for address translation (broken in older kernels too),
>>> two are build problems when CONFIG_MMU is disabled, and the last is the
>>> actuall configuration changes needed.
>>>
>>> The motivation for this is that the versatile machine is well supported
>>> in qemu. And this provides an excellent platform for development and
>>> testing no-MMU support on ARM in general. With these patches applied
>>> it is possible to build and run a kernel with MMU disabled on qemu.
>>
>> I'm wondering if my "Allow NOMMU for MULTIPLATFORM" series [1] work for you?
>>
>> [1] https://www.spinics.net/lists/arm-kernel/msg546823.html
>
> Sorry I hadn't seen these patches before.
>
> Just tried them out. With CONFIG_EXPERT set I can select and
> build for the Versatile machine with CONFIG_MMU not set. The
> build is successful, but the resulting kernel doesn't boot.
It is why "no guarantee" there ;)
>
> I see that the resulting .config has CONFIG_PLAT_VERSATILE set
> but not CONFIG_ARCH_VERSATILE. Is this intentional?
No.
>
> With CONFIG_ARCH_VERSATILE missing the build doesn't traverse
> into arch/arm/mach-versatile, and you don't get any device tree
> built.
>
I've just done:
$ make ARCH=arm versatile_defconfig nommu.config
...
$ grep VERSATILE .config 1 CONFIG_ARCH_VERSATILE=y
CONFIG_PLAT_VERSATILE=y
CONFIG_I2C_VERSATILE=y
CONFIG_POWER_RESET_VERSATILE=y
CONFIG_PLAT_VERSATILE_CLCD=y
# CONFIG_LEDS_VERSATILE is not set
CONFIG_COMMON_CLK_VERSATILE=y
CONFIG_CLKSRC_VERSATILE=y
CONFIG_VERSATILE_FPGA_IRQ=y
CONFIG_VERSATILE_FPGA_IRQ_NR=4
CONFIG_DEBUG_VERSATILE=y
$ cat arch/arm/configs/nommu.config
CONFIG_EXPERT=y
# CONFIG_MMU is not set
I didn't submit nommu config fragment, but it is is what I've been using to
simplify defconfigs and randconfig builds.
> Ultimately to produce a working kernel we will still need my
> patch 01/04 ("ARM: versatile: support no-MMU mode addressing").
> No surprise here, this was missing in older kernels too.
Agreed.
Cheers
Vladimir
>
> Regards
> Greg
>
>
>>>
>>> Signed-off-by: Greg Ungerer <gerg@uclinux•org>
>>> ---
>>> arch/arm/Kconfig | 10 ++++++++++
>>> arch/arm/Kconfig.debug | 3 ++-
>>> arch/arm/include/asm/mach/map.h | 1 +
>>> arch/arm/mach-versatile/Kconfig | 3 ++-
>>> arch/arm/mach-versatile/Makefile.boot | 3 +++
>>> arch/arm/mach-versatile/versatile_dt.c | 4 ++++
>>> 6 files changed, 22 insertions(+), 2 deletions(-)
>>>
>>>
>>> _______________________________________________
>>> linux-arm-kernel mailing list
>>> linux-arm-kernel at lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>>
>>
>>
>
next prev parent reply other threads:[~2016-12-07 14:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 6:08 [PATCH 0/4] arm/versatile: no-MMU support Greg Ungerer
2016-12-07 6:08 ` [PATCH 1/4] ARM: versatile: support no-MMU mode addressing Greg Ungerer
2016-12-07 6:08 ` [PATCH 2/4] ARM: versatile: define empty debug_ll_io_init() for no-MMU Greg Ungerer
2016-12-07 9:23 ` [PATCH 0/4] arm/versatile: no-MMU support Vladimir Murzin
2016-12-07 13:57 ` Greg Ungerer
2016-12-07 14:13 ` Vladimir Murzin [this message]
2016-12-07 14:21 ` Greg Ungerer
2016-12-07 14:27 ` Vladimir Murzin
2016-12-07 14:40 ` Greg Ungerer
2016-12-07 14:16 ` Linus Walleij
-- strict thread matches above, loose matches on Subject: below --
2016-09-26 0:52 Greg Ungerer
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