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

[Zhiqiang Hou]

Hi Rod and Chenhui,

Can you help to answer the questions about PSCI and PPA?

> -----Original Message-----
> From: york sun
> Sent: 2016年1月23日 4:30
> To: Bhupesh Sharma <bhupesh.sharma at nxp.com>; Scott Wood
> <oss at buserror.net>; Zhiqiang Hou <Zhiqiang.Hou at freescale.com>; u-
> boot at lists.denx.de; albert.u.boot at aribaud.net; Mingkai.hu at freescale.com;
> Stuart Yoder <stuart.yoder at nxp.com>; leoli at freescale.com;
> prabhakar at freescale.com; bhupesh.sharma at freescale.com; Zhiqiang Hou
> <zhiqiang.hou at nxp.com>
> Subject: Re: [PATCHv2 2/3] ARMv8/layerscape: Add FSL PPA support
> 
> 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/bindi
> >>>> n
> >>>> 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.
> 

Chenhui is working on it.

Thanks,
Zhiqiang