[PATCH 5/6] powerpc/fsl-pci: Add pci inbound/outbound PM support

[Jia Hongtao-B38951]

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Tuesday, August 07, 2012 11:35 PM
> To: Jia Hongtao-B38951
> Cc: Kumar Gala; linuxppc-dev at lists.ozlabs.org; Wood Scott-B07421; Li
> Yang-R58472
> Subject: Re: [PATCH 5/6] powerpc/fsl-pci: Add pci inbound/outbound PM
> support
> 
> On 08/07/2012 05:11 AM, Jia Hongtao-B38951 wrote:
> >
> >
> >> -----Original Message-----
> >> From: Kumar Gala [mailto:galak at kernel.crashing.org]
> >> Sent: Tuesday, July 31, 2012 9:37 PM
> >> To: Jia Hongtao-B38951
> >> Cc: linuxppc-dev at lists.ozlabs.org; Wood Scott-B07421; Li Yang-R58472
> >> Subject: Re: [PATCH 5/6] powerpc/fsl-pci: Add pci inbound/outbound PM
> >> support
> >>
> >>
> >> On Jul 30, 2012, at 1:09 AM, Jia Hongtao-B38951 wrote:
> >>
> >>>> -----Original Message-----
> >>>> From: Kumar Gala [mailto:galak at kernel.crashing.org]
> >>>> Sent: Friday, July 27, 2012 9:24 PM
> >>>> To: Jia Hongtao-B38951
> >>>> Cc: linuxppc-dev at lists.ozlabs.org; Wood Scott-B07421; Li
> >>>> Yang-R58472
> >>>> Subject: Re: [PATCH 5/6] powerpc/fsl-pci: Add pci inbound/outbound
> >>>> PM support
> >>>>
> >>>>
> >>>> On Jul 24, 2012, at 5:20 AM, Jia Hongtao wrote:
> >>>>
> >>>>> Power supply for PCI inbound/outbound window registers is off when
> >>>> system
> >>>>> go to deep-sleep state. We save the values of registers before
> >>>>> suspend and restore to registers after resume.
> >>>>>
> >>>>> Signed-off-by: Jiang Yutang <b14898 at freescale.com>
> >>>>> Signed-off-by: Jia Hongtao <B38951 at freescale.com>
> >>>>> Signed-off-by: Li Yang <leoli at freescale.com>
> >>>>> ---
> >>>>> arch/powerpc/include/asm/pci-bridge.h |    2 +-
> >>>>> arch/powerpc/sysdev/fsl_pci.c         |  121
> >>>> +++++++++++++++++++++++++++++++++
> >>>>> 2 files changed, 122 insertions(+), 1 deletions(-)
> >>>>
> >>>> Remind me why we need to save/restore PCI ATMUs, why not just
> >>>> re-parse the device tree to restore?
> >>>>
> >>>> - k
> >>>
> >>> Save/restore is the more efficient way. Latency of sleep/wakeup is
> >>> one of most important features in power management.
> >>>
> >>> -Hongtao.
> >>
> >> I don't think the time it takes to run through setup_pci_atmu() is
> >> that long compared to fsl_pci_resume().
> >>
> >> Also, don't you need to setup PCICCSRBAR and do setup_pci_cmd() on
> resume?
> >>
> >> - k
> >
> > Hi Kumar,
> > I did some tests on P1022DS and found out that PCI_CMD and PCICSRBAR
> > is not lost when system in deep sleep. We don't need to save it.
> 
> How does the PCI code know you're entering deep sleep and not hibernation?
> 
> -Scott

When system come back from hibernation PCI will be initialized again.
So no need to save PCI_CMD and PEXCSRBAR.

-Hongtao.