[U-Boot] [RFC PATCH 4/5] arm: v7R: Add support for MPU

[Lokesh Vutla]

On Tuesday 24 April 2018 06:50 PM, Tom Rini wrote:
> On Tue, Apr 24, 2018 at 06:24:47PM +0530, Lokesh Vutla wrote:
> 
>> The Memory Protection Unit(MPU) allows to partition memory into regions
>> and set individual protection attributes for each region. In absence
>> of MPU a default map[1] will take effect. Add support for configuring
>> MPU on Cortex-R, by reusing the existing support for Cortex-M processor.
>>
>> [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0460d/I1002400.html
>>
>> Signed-off-by: Lokesh Vutla <lokeshvutla at ti.com>
>> ---
>>  arch/arm/Kconfig                  |  11 +++
>>  arch/arm/cpu/armv7/Makefile       |   2 +
>>  arch/arm/cpu/armv7/mpu_v7r.c      | 109 ++++++++++++++++++++++++++++++
>>  arch/arm/cpu/armv7m/Makefile      |   3 +-
>>  arch/arm/cpu/armv7m/mpu.c         |  41 +----------
>>  arch/arm/include/asm/armv7m_mpu.h |  69 +++++++++++++++++++
> 
> How close are armv7/mpu_v7r.c and armv7m/mpu.c ?  If we did some
> underlying work so that armv7m/ and be put into armv7/ (and we introduce
> CPU_V7A say, as I mentioned in another part of the thread so the
> Makefile isn't too ugly) could we have a single mpu.c file, cleanly?
> 

I did start with that but found out that the way we program the mpu
registers are entirely different. For v7m mmio registers are used, but
for v7r system registers are used. I couldn't find a way to get a common
driver for these two. If you prefer #ifdefs and merged these two, I can
do it but it doesn't look clean.

Thanks and regards,
Lokesh