[U-Boot] [PATCH V2 2/3] mx7: psci: add basic psci support

[Li Frank]

> -----Original Message-----
> From: Albert ARIBAUD [mailto:albert.u.boot at aribaud.net]
> Sent: Tuesday, October 20, 2015 4:04 PM
> To: Li Frank-B20596 <Frank.Li at freescale.com>
> Cc: Fan Peng-B51431 <Peng.Fan at freescale.com>; Estevam Fabio-R49496
> <Fabio.Estevam at freescale.com>; u-boot at lists.denx.de
> Subject: Re: [U-Boot] [PATCH V2 2/3] mx7: psci: add basic psci support
> 
> Hello Li,
> 
> (sorry for my dropping other receipients from the discussion; restoring them
> 
> On Tue, 20 Oct 2015 15:04:40 +0000, Li Frank <Frank.Li at freescale.com>
> wrote:
> >
> >
> > > -----Original Message-----
> > > From: Albert ARIBAUD [mailto:albert.u.boot at aribaud.net]
> > > Sent: Tuesday, October 20, 2015 9:55 AM
> > > To: Li Frank-B20596 <Frank.Li at freescale.com>
> > > Subject: Re: [U-Boot] [PATCH V2 2/3] mx7: psci: add basic psci
> > > support
> > >
> > > Hello Li,
> > >
> > > On Tue, 20 Oct 2015 14:29:46 +0000, Li Frank
> > > <Frank.Li at freescale.com>
> > > wrote:
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Albert ARIBAUD [mailto:albert.u.boot at aribaud.net]
> > > > > Sent: Tuesday, October 20, 2015 9:25 AM
> > > > > To: Li Frank-B20596 <Frank.Li at freescale.com>
> > > > > Cc: Fan Peng-B51431 <Peng.Fan at freescale.com>;
> > > > > u-boot at lists.denx.de; Estevam Fabio-R49496
> > > > > <Fabio.Estevam at freescale.com>
> > > > > Subject: Re: [U-Boot] [PATCH V2 2/3] mx7: psci: add basic psci
> > > > > support
> > > > >
> > > > > Hello Li,
> > > > >
> > > > > On Tue, 20 Oct 2015 14:05:45 +0000, Li Frank
> > > > > <Frank.Li at freescale.com>
> > > > > wrote:
> > > > > >
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Peng Fan [mailto:Peng.Fan at freescale.com]
> > > > > > > Sent: Tuesday, October 20, 2015 1:00 AM
> > > > > > > To: u-boot at lists.denx.de
> > > > > > > Cc: Fan Peng-B51431 <Peng.Fan at freescale.com>; Li
> > > > > > > Frank-B20596 <Frank.Li at freescale.com>; Stefano Babic
> > > > > > > <sbabic at denx.de>; Estevam
> > > > > > > Fabio-
> > > > > > > R49496 <Fabio.Estevam at freescale.com>
> > > > > > > Subject: [PATCH V2 2/3] mx7: psci: add basic psci support
> > > > > > >
> > > > > > > 1. add basic psci support for imx7 chip.
> > > > > > > 2. support cpu_on and cpu_off.
> > > > > > > 3. switch to non-secure mode when boot linux kernel.
> > > > > > > 4. set csu allow accessing all peripherial register in non-secure
> mode.
> > > > > > >
> > > > > > > Signed-off-by: Frank Li <Frank.Li at freescale.com>
> > > > > > > Signed-off-by: Peng Fan <Peng.Fan at freescale.com>
> > > > > > > Cc: Stefano Babic <sbabic at denx.de>
> > > > > > > Cc: Fabio Estevam <fabio.estevam at freescale.com>
> > > > > > > ---
> > > > > > >
> > > > > > > Changes V2:
> > > > > > >  Refine commit msg.
> > > > > > >
> > > > > > >  arch/arm/cpu/armv7/mx7/Makefile   |  4 ++
> > > > > > >  arch/arm/cpu/armv7/mx7/psci-mx7.c | 78
> > > > > > > +++++++++++++++++++++++++++++++++++++++
> > > > > > >  arch/arm/cpu/armv7/mx7/psci.S     | 54
> > > +++++++++++++++++++++++++++
> > > > > > >  arch/arm/cpu/armv7/mx7/soc.c      |  9 +++++
> > > > > > >  4 files changed, 145 insertions(+)  create mode 100644
> > > > > > > arch/arm/cpu/armv7/mx7/psci-mx7.c  create mode
> > > > > > > 100644 arch/arm/cpu/armv7/mx7/psci.S
> > > > > > >
> > > > > > > diff --git a/arch/arm/cpu/armv7/mx7/Makefile
> > > > > > > b/arch/arm/cpu/armv7/mx7/Makefile index e6ecef0..f25461c
> > > > > > > 100644
> > > > > > > --- a/arch/arm/cpu/armv7/mx7/Makefile
> > > > > > > +++ b/arch/arm/cpu/armv7/mx7/Makefile
> > > > > > > @@ -6,3 +6,7 @@
> > > > > > >  #
> > > > > > >
> > > > > > >  obj-y	:= soc.o clock.o clock_slice.o
> > > > > > > +
> > > > > > > +ifdef CONFIG_ARMV7_PSCI
> > > > > > > +obj-y  += psci.o psci-mx7.o
> > > > > >
> > > > > > Obj-y += psci-mx7.o psci.o
> > > > > > The otherwise psci_text_end will not be last one.
> > > > >
> > > > > I don't like this object module order sensitivity.
> > > > >
> > > > > The object module order of secure code modules should not affect
> > > > > the resulting binary to the point of possibly preventing it from
> > > > > working
> > > > > -- after all, the object module order of 'vanilla' image code
> > > > > does not matter (1). We don't have this kind of problem when
> > > > > defining the image start and end, why would we have it with the
> > > > > secure code start and
> > > end?
> > > >
> > > > Secure code use psci_text_end to calculate stack top point.
> > >
> > > Yes, and that does not require defining psci_text_end in an object
> > > module, nor does it require specific object module ordering.
> >
> > If psci_text_end in mid of secure text,
> > And psci_text_end + 1k < total secure text size,   stack will overwrite the code.
> 
> This is a good reason to allocate the PSCCI stack and create a symbol for its top
> in the linker script.
> 
> > > > > IOW, psci_text_end could (and should) be defined in the linker
> > > > > script, not in an object module.
> > > >
> > > > I agree.  The other platform put psci_text_end to object module.
> > >
> > > Which 'other platform' is this?
> >
> > arch/arm/cpu/armv7/sunxi
> > arch/arm/cpu/armv7/ls102xa
> 
> Ok, but they all use the same routine for moving the PSCI code and setting its
> stack, right?

Yes.

Best regards
Frank Li
> 
> Amicalement,
> --
> Albert.