[PATCH 2/2] arm: add early_ioremap support

[Rob Herring]

On Tue, Jul 22, 2014 at 11:48 AM, Tomasz Figa <t.figa at samsung.com> wrote:
> Hi Leif,
>
> On 09.07.2014 11:39, Leif Lindholm wrote:
>> From: Mark Salter <msalter at redhat.com>
>>
>> This patch uses the generic early_ioremap code to implement
>> early_ioremap for ARM. The ARM-specific bits come mostly from
>> an earlier patch from Leif Lindholm <leif.lindholm at linaro.org>
>> here:
>>
>>   https://lkml.org/lkml/2013/10/3/279
>
> [snip]
>
>> diff --git a/arch/arm/mm/early_ioremap.c b/arch/arm/mm/early_ioremap.c
>> new file mode 100644
>> index 0000000..1013109
>> --- /dev/null
>> +++ b/arch/arm/mm/early_ioremap.c
>> @@ -0,0 +1,86 @@
>> +/*
>> + * early_ioremap() support for ARM
>> + *
>> + * Based on existing support in arch/x86/mm/ioremap.c
>> + *
>> + * Restrictions: currently only functional before paging_init()
>
> Uhm, that's bad... This would explain why my earlycon code generates a
> fault as soon as something prints after paging_init(). I'd say this
> feature would be much more useful if mappings were carried over
> paging_init(), so that mapped devices are available later as well.
>
> I'll see if I can code this on top of your patch, but unfortunately it
> might end up with -ENOTIME.

I have fixmap support that's needed for earlycon. Here is the branch:

git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git fixmap

It is based on an earlier version of patchset and not on the latest
version from Leif. Unfortunately, I don't have more time to spend on
it ATM.

Rob