Re: [PATCH] powerpc/85xx: Save and restore pcie ATMU windows for PM

On May 20, 2011, at 12:01 AM, Kushwaha Prabhakar-B32579 wrote:

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-----Original Message-----
From: Kumar Gala [mailto:galak@kernel.crashing.org]
Sent: Friday, May 20, 2011 10:19 AM
To: Kushwaha Prabhakar-B32579
Cc: linuxppc-dev@lists.ozlabs.org; meet2prabhu@gmail.com; Jiang =

Yutang-

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B14898
Subject: Re: [PATCH] powerpc/85xx: Save and restore pcie ATMU windows =

for

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PM
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On May 19, 2011, at 11:41 PM, Kushwaha Prabhakar-B32579 wrote:
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-----Original Message-----
From: Kumar Gala [mailto:galak@kernel.crashing.org]
Sent: Thursday, May 19, 2011 6:53 PM
To: Kushwaha Prabhakar-B32579
Cc: linuxppc-dev@lists.ozlabs.org; meet2prabhu@gmail.com; Jiang
Yutang-
B14898
Subject: Re: [PATCH] powerpc/85xx: Save and restore pcie ATMU =

windows

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for PM
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On May 19, 2011, at 6:22 AM, Kushwaha Prabhakar-B32579 wrote:
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Hi Kumar,
Please find my answer in-lined
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-----Original Message-----
From: Kumar Gala [mailto:galak@kernel.crashing.org]
Sent: Thursday, May 19, 2011 12:00 PM
To: Kushwaha Prabhakar-B32579
Cc: linuxppc-dev@lists.ozlabs.org; meet2prabhu@gmail.com; Jiang
Yutang-
B14898
Subject: Re: [PATCH] powerpc/85xx: Save and restore pcie ATMU
windows for PM
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On Apr 28, 2011, at 1:38 AM, Prabhakar Kushwaha wrote:
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D3-cold state indicates removal of the clock and power. however
auxiliary (AUX) Power may remain available even after the main
power

rails are powered down.

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wakeup from D3-cold state requires full context restore. Other
things are taken care in pci-driver except ATMUs.
ATMU windows needs to be saved and restored during suspend and

resume.

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Signed-off-by: Jiang Yutang <redacted>
Signed-off-by: Prabhakar Kushwaha <redacted>
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Based upon
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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.g

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it
(b
ranch master)
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arch/powerpc/sysdev/fsl_pci.c |  116

+++++++++++++++++++++++++++++++++++++++++

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arch/powerpc/sysdev/fsl_pci.h |    7 ++-
2 files changed, 121 insertions(+), 2 deletions(-)

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Is this patch for when we are a host or agent?

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This patch is independent of host or agent. It is for supporting =

D3

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cold state for P1022.

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These functions are called during System level suspend and resume.
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--Prabhakar

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I'm trying to figure out why this is limited to P1022.

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Till now, No SOC was supporting D3 cold state. First time P1022

supporting it.

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Note:  D3 cold state =3D=3D PCIe block Power down
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I'm wondering a few things:
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1. Is there any reason not to do this for ALL FSL PCIe SoCs?

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Yes, I am agree with you. It can be done.=20
But as only P1022 SOC supporting it. There is no use of handling it.

I'm also not clear if the DECLARE_PCI_FIXUP_SUSPEND() is the right way =
for us to connect up these suspend/resume functions.

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2. why do bother saving state, we don't we re-parse the .dts and
reconfigure ATMUs that way?

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I also thought of this case. But Agent use case scenario forbid me to =

do this.=20

As ATMU's are programmed by host depending upon different use case . =

And this information is never stored in the dts.

Fair point, but in agent mode will this code ever really be called?  It =
seems like we'd never register ourselves with the PCI subsystem so how =
would this get called?

- k=