[U-Boot] [PATCHv2 2/3] ARMv8/layerscape: Add FSL PPA support

[york sun]

On 01/22/2016 12:27 PM, Bhupesh Sharma wrote:
> 
> 
>> -----Original Message-----
>> From: Scott Wood [mailto:oss at buserror.net]
>> Sent: Saturday, January 23, 2016 1:52 AM
>> To: york sun; Bhupesh Sharma; Zhiqiang Hou; u-boot at lists.denx.de;
>> albert.u.boot at aribaud.net; Mingkai.hu at freescale.com; Stuart Yoder;
>> leoli at freescale.com; prabhakar at freescale.com;
>> bhupesh.sharma at freescale.com; Zhiqiang Hou
>> Subject: Re: [PATCHv2 2/3] ARMv8/layerscape: Add FSL PPA support
>>
>> On Fri, 2016-01-22 at 20:18 +0000, york sun wrote:
>>> On 01/22/2016 12:14 PM, Bhupesh Sharma wrote:
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: Scott Wood [mailto:oss at buserror.net]
>>>>> Sent: Saturday, January 23, 2016 1:39 AM
>>>>> To: york sun; Zhiqiang Hou; u-boot at lists.denx.de;
>>>>> albert.u.boot at aribaud.net; Mingkai.hu at freescale.com; Stuart Yoder;
>>>>> leoli at freescale.com; prabhakar at freescale.com;
>>>>> bhupesh.sharma at freescale.com; Zhiqiang Hou
>>>>> Subject: Re: [PATCHv2 2/3] ARMv8/layerscape: Add FSL PPA support
>>>>>
>>>>> On Fri, 2016-01-22 at 20:05 +0000, york sun wrote:
>>>>>> On 01/21/2016 01:53 AM, Zhiqiang Hou wrote:
>>>>>>> From: Hou Zhiqiang <Zhiqiang.Hou at freescale.com>
>>>>>>>
>>>>>>> The FSL Primary Protected Application (PPA) is a software
>>>>>>> component loaded during boot which runs in TrustZone and
>>>>>>> remains resident after boot.
>>>>>>>
>>>>>>> Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou at freescale.com>
>>>>>>> ---
>>>>>>> Tested on LS1043A RDB board
>>>>>>>
>>>>>>
>>>>>> I presume PSCI is implemented in PPA. How does the SMP boot flow
>>>>>> change with PPA? U-boot has to remain functional in the absence
>>>>>> of PPA,
>>>>> right?
>>>>>>
>>>>>> Would it be possible to write a readme for PPA?
>>>>>
>>>>> Also, how does the devicetree get updated to indicate the presence
>>>>> of PSCI?
>>>>>
>>>>
>>>> One needs to add PSCI node in the DTS for the same, claiming support
>>>> for PSCI specification.
>>>> The cpu.enable_method needs to be changed from spin-table to psci as
>> well.
>>>>
>>>> See
>>>> http://lxr.free-electrons.com/source/Documentation/devicetree/bindin
>>>> gs
>>>> /arm/psci.txt for details.
>>>>
>>>
>>> Bhupesh,
>>>
>>> Before PPA is fully adopted, u-boot has to detect the existence of PPA
>>> and decide to use PSCI or spin table, right? So the device tree node
>>> should also be fixed accordingly.
> 
> A static CONFIG_ flag is used for enabling the PPA support currently in QorIQ-LS u-boot code.

Not enough. The driver parse PPA image and gives up if it is not a valid image.
Before we have a way to deploy PPA image to all our customers, we need to keep
both options open.

York