[U-Boot] [PATCH v2] vexpress: disable cci ace slave ports when booting in non-sec/hyp mode

[Sudeep Holla]

On 26/09/16 14:19, Jon Medhurst (Tixy) wrote:
> On Mon, 2016-09-26 at 13:38 +0100, Sudeep Holla wrote:
>>
>> On 26/09/16 13:30, Jon Medhurst (Tixy) wrote:
>>> On Fri, 2016-09-23 at 17:38 +0100, Sudeep Holla wrote:
>>>> Commit f225d39d3093 ("vexpress: Check TC2 firmware support before defaulting
>>>> to nonsec booting") added support to check if the firmware on TC2  is
>>>> configured appropriately before booting in nonsec/hyp mode.
>>>>
>>>> However when booting in non-secure/hyp mode, CCI control must be done in
>>>> secure firmware and can't  be done in non-secure/hyp mode. In order to
>>>> ensure that, this patch disables the cci slave port inteface so that it
>>>> is not accessed at all.
>>>>
>>>> Cc: Jon Medhurst <tixy at linaro.org>
>>>> Acked-by: Marc Zyngier <marc.zyngier at arm.com>
>>>> Signed-off-by: Sudeep Holla <sudeep.holla at arm.com>
>>>> ---
>>>
>>> Acked-by: Jon Medhurst <tixy at linaro.org>
>>> Tested-by: Jon Medhurst <tixy at linaro.org>
>>
>> So, can I assume the missing kernel patches to be reason for boot hang ?
>> Just wanted to know if I need to investigate that any further ?
>
> Sorry, yes they were the reason and no further investigation needed. I
> remembered getting nonsec mode working some month's ago without such
> patches, but I remember now that was by disabling MCPM in the kernel.
>
> This morning I tried these U-Boot patches successfully with:
> - Upstream vexpress_defconfig kernel booting with 'sec' mode
> - That kernel with Lorenzo's patches in both 'sec' and 'nonsec'
> - As above with CONFIG_BL_SWITCHER enabled
>
> When booting in nonsec I also verified the device-tree modifications
> made by this patch by seeing the following files existed and contained
> the word 'disabled'...
>
> /proc/device-tree/cci at 2c090000/slave-if at 4000/status
> /proc/device-tree/cci at 2c090000/slave-if at 5000/status
>

That was very detailed :), thanks for testing and confirming. I too did
similar examination and didn't find anything odd so far.

-- 
Regards,
Sudeep