[PATCH][V4] powerpc/fsl-pci: Add pci inbound/outbound PM support

[Li Yang-R58472]

> -----Original Message-----
> From: Jia Hongtao-B38951
> Sent: Friday, September 21, 2012 11:14 AM
> To: Kumar Gala
> Cc: linuxppc-dev at lists.ozlabs.org; Li Yang-R58472; Wood Scott-B07421
> Subject: RE: [PATCH][V4] powerpc/fsl-pci: Add pci inbound/outbound PM
> support
> 
> 
> 
> > -----Original Message-----
> > From: Kumar Gala [mailto:galak at kernel.crashing.org]
> > Sent: Wednesday, September 19, 2012 11:49 PM
> > To: Jia Hongtao-B38951
> > Cc: linuxppc-dev at lists.ozlabs.org; Li Yang-R58472; Wood Scott-B07421
> > Subject: Re: [PATCH][V4] powerpc/fsl-pci: Add pci inbound/outbound PM
> > support
> >
> > >>> On Sep 17, 2012, at 9:10 PM, 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>
> > >>>> ---
> > >>>> Changes for V4:
> > >>>> We just rebase the patch upon following patch:
> > >>>> powerpc/fsl-pci: Unify pci/pcie initialization code
> > >>>>
> > >>>> arch/powerpc/include/asm/pci-bridge.h |    2 +-
> > >>>> arch/powerpc/sysdev/fsl_pci.c         |  121
> > >>> +++++++++++++++++++++++++++++++++
> > >>>> 2 files changed, 122 insertions(+), 1 deletions(-)
> > >>>
> > >>> Did you ever compare this to just re-parsing device tree method?
> > >>>
> > >>> - k
> > >>
> > >> I tested the re-parsing way by using setup_pci_atmu() when resume.
> > >> And I found out that re-parsing will *change* outbound IO
> > >> translation address regitster.
> > >>
> > >> It seems that in the first bootup, after setup_atmu()
> > >> pcibios_setup_phb_resources() may update hose->io_resource, but
> > >> atmu is not updated according to the new hose->io_resource value.
> > >> In resume from sleep setup_atmu() will reset atmu according to the
> > >> new hose->io_resource value. So the setup_atmu() will cause
> > >> different result on outbound IO register between first bootup and
> > >> resume from sleep.
> > >>
> > >> So... There's a possibility that in the first bootup atmu is not
> > >> setup properly.
> > >
> > > [Are you seeing this happen in your testing?  If so its a bug we
> > > need
> > to look at fixing.]
> > >
> > > Yes, I see this in my testing.
> > > Also PCIe ethernet card works well after resuming from sleep in both
> > save/restore
> > > and re-parsing way. (Maybe PCIe ethernet card don't need outbound IO
> > resource)
> > > So, I guess the result of re-parsing (actually it's re-setup) is
> > > right
> > and ATMU is not setup
> > > properly at the first bootup.
> >
> > Are you seeing the following message - "PCI: I/O resource not set for
> > host bridge" ?
> 
> No.
> 
> >
> > Trying to understand why you'd hit the reassignment of io_resource.
> >
> > - k
> >
> 
> I did some investigations and the conclusion is:
> 
> io_resource.flags & IORESOURCE_IO are both positive but io_resource.start
> is 0 before pcibios_setup_phb_io_space() is done.
> 
> The sequence of related process listed below:
> fsl_add_bridge() -> setup_pci_atmu()
> pcibios_init() -> pcibios_scan_phb() -> pcibios_setup_phb_io_space()
> 
> Because fsl_add_bridge() must be finished before pcibios_init() so ATMU
> is set when io_resource.start is 0. That means outbound IO regs are not
> set.
> 
> If system re-setup ATMU the io_resource.start has already updated so
> outbound IO regs are set.
> 
> My question is:
> Is there any problem if outbound IO regs are not set in first bootup?

Please also provide the IO resource address range before and after the pci scan.  Then we can evaluate if the range is needed to be mapped via ATMU.

Leo