[PATCH 4/5] ARM: EXYNOS: Add support for Exynos secure firmware

Kyungmin Park kyungmin.park at samsung.com
Sat Sep 22 02:39:27 EDT 2012

On 9/22/12, Olof Johansson <olof at lixom.net> wrote:
> On Fri, Sep 21, 2012 at 10:57 PM, Kyungmin Park
> <kyungmin.park at samsung.com> wrote:
>> On 9/22/12, Olof Johansson <olof at lixom.net> wrote:
>>> On Wed, Sep 19, 2012 at 3:10 AM, Tomasz Figa <t.figa at samsung.com> wrote:
>>>> Hi Olof,
>>>> On Saturday 15 of September 2012 17:44:55 Olof Johansson wrote:
>>>>> On Thu, Sep 13, 2012 at 10:13:37AM +0200, Tomasz Figa wrote:
>>>>> > +static void __iomem *exynos_cpu_boot_reg(int cpu)
>>>>> > +{
>>>>> > +   return S5P_VA_SYSRAM_NS + 0x1c + 4*cpu;
>>>>> > +}
>>>>> This communication area in sysram should probably be seen as a part of
>>>>> the firmware interface. It should thus be defined as part of the
>>>>> binding
>>>>> instead, i.e.  through a reg property or similar there. That also
>>>>> would
>>>>> make it easy to convert to using ioremap() instead of iodesc tables,
>>>>> which always a nice thing.
>>>> The problem with SYSRAM_NS is that it might be also used in other code,
>>>> not
>>>> related to firmware only. I don't know exactly all the use cases for
>>>> it.
>>> If you don't know the use cases, and the use cases are not in the
>>> kernel tree that we care about here (upstream), then there's really
>>> nothing to worry about. It's after all just a define that's moved to
>>> an ioremap, if there's some out of tree code that needs the old legacy
>>> define then it can be added in whatever out-of-tree code that uses it.
>>> Right?
>> Now this address is used at cpu boot, cpuidle, inform at this time.
>> As it touched at several places, it's defined at iodesc. if it changed
>> with ioremap, it has to export remaped address and each codes should
>> use it.
> Won't you have to push down all the references to VA_SYSRAM vs
> VA_SYSRAM_NS into the firmware interface anyway, since you will need
> to use different addresses for whether you have firmware enabled or
> not? I.e. you'll have a "firmware call" at the appropriate level for
> the non-trustzone cases that uses the equivalent of VA_SYSRAM, and for
> the trustzone firmware op you'll use VA_SYSRAM_NS?
Right, in case of no firmware, it uses VA_SYSRAM, but VA_SYSRAM_NS is
used at firmware case.
>> As I wrote at cover letter, if you want to use ioremap, it can be
>> modified. however can you merge firmware codes itself? since ioremap
>> is not related with trustzone  or firmware issues and it's exynos
>> specific implementation issues. Right?
> I'm not quite sure which part you are asking me to merge, if it's the
> infrastructure pieces or the exynos-specific pieces.
> Either way, one isn't really usable without the other, and it doesn't
> make sense to merge code that can't be used. Infrastructure is best
> merged together with the first user of it.

Okay, we will fix it.

Thank you,
Kyungmin Park

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