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

[Jia Hongtao-B38951 <B38951@freescale.com>]

> -----Original Message-----
> From: Kumar Gala [mailto:galak@kernel.crashing.org]
> Sent: Tuesday, July 31, 2012 9:37 PM
> To: Jia Hongtao-B38951
> Cc: linuxppc-dev@lists.ozlabs.org; Wood Scott-B07421; Li Yang-R58472
> Subject: Re: [PATCH 5/6] powerpc/fsl-pci: Add pci inbound/outbound PM
> support
>=20
>=20
> On Jul 30, 2012, at 1:09 AM, Jia Hongtao-B38951 wrote:
>=20
> >> -----Original Message-----
> >> From: Kumar Gala [mailto:galak@kernel.crashing.org]
> >> Sent: Friday, July 27, 2012 9:24 PM
> >> To: Jia Hongtao-B38951
> >> Cc: linuxppc-dev@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@freescale.com>
> >>> Signed-off-by: Jia Hongtao <B38951@freescale.com>
> >>> Signed-off-by: Li Yang <leoli@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.
>=20
> I don't think the time it takes to run through setup_pci_atmu() is that
> long compared to fsl_pci_resume().
>=20
> Also, don't you need to setup PCICCSRBAR and do setup_pci_cmd() on resume=
?
>=20
> - 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.

I will send PM patch after PCI initialization patch set being accepted.=20

-Hongtao.