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

[Kumar Gala <galak@kernel.crashing.org>]

On May 19, 2011, at 11:41 PM, Kushwaha Prabhakar-B32579 wrote:

>=20
>=20
>> -----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 =
for
>> PM
>>=20
>>=20
>> On May 19, 2011, at 6:22 AM, Kushwaha Prabhakar-B32579 wrote:
>>=20
>>> Hi Kumar,
>>> Please find my answer in-lined
>>>=20
>>>> -----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
>>>>=20
>>>>=20
>>>> On Apr 28, 2011, at 1:38 AM, Prabhakar Kushwaha wrote:
>>>>=20
>>>>> 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.
>>>>>=20
>>>>> 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.
>>>>>=20
>>>>> Signed-off-by: Jiang Yutang <b14898@freescale.com>
>>>>> Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
>>>>> ---
>>>>> Based upon
>>>>> =
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
>>>>> (b
>>>>> ranch master)
>>>>>=20
>>>>> arch/powerpc/sysdev/fsl_pci.c |  116
>>>> +++++++++++++++++++++++++++++++++++++++++
>>>>> arch/powerpc/sysdev/fsl_pci.h |    7 ++-
>>>>> 2 files changed, 121 insertions(+), 2 deletions(-)
>>>>=20
>>>> Is this patch for when we are a host or agent?
>>>=20
>>> This patch is independent of host or agent. It is for supporting D3
>> cold state for P1022.
>>> These functions are called during System level suspend and resume.
>>>=20
>>> --Prabhakar
>>=20
>> I'm trying to figure out why this is limited to P1022.
>=20
> Till now, No SOC was supporting D3 cold state. First time P1022 =
supporting it.
> Note:  D3 cold state =3D=3D PCIe block Power down
>=20

I'm wondering a few things:

1. Is there any reason not to do this for ALL FSL PCIe SoCs?
2. why do bother saving state, we don't we re-parse the .dts and =
reconfigure ATMUs that way?

- k