linux-kernel - RE: [PATCH v2] PCI: designware: move remaining rc setup code to dw_pcie_setup

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Message-ID: <EE11001F9E5DDD47B7634E2F8A612F2E1ED43F7E@lhreml503-mbs>
Date:	Thu, 7 Apr 2016 08:14:00 +0000
From:	Gabriele Paoloni <gabriele.paoloni@...wei.com>
To:	Pratyush Anand <pratyush.anand@...il.com>
CC:	Jisheng Zhang <jszhang@...vell.com>,
	"jingoohan1@...il.com" <jingoohan1@...il.com>,
	"bhelgaas@...gle.com" <bhelgaas@...gle.com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: RE: [PATCH v2] PCI: designware: move remaining rc setup code to
 dw_pcie_setup_rc()

Hi Pratyush

Many thanks for quick replying

> -----Original Message-----
> From: Pratyush Anand [mailto:pratyush.anand@...il.com]
> Sent: 07 April 2016 07:59
> To: Gabriele Paoloni
> Cc: Jisheng Zhang; jingoohan1@...il.com; bhelgaas@...gle.com; linux-
> pci@...r.kernel.org; linux-kernel@...r.kernel.org; linux-arm-
> kernel@...ts.infradead.org
> Subject: Re: [PATCH v2] PCI: designware: move remaining rc setup code
> to dw_pcie_setup_rc()
> 
> Hi Gab,
> 
> Thanks for bringing it.
> 
> 
> On Wed, Apr 6, 2016 at 8:20 PM, Gabriele Paoloni
> <gabriele.paoloni@...wei.com> wrote:
> > Hi, sorry to be late on this
> >
> >> -----Original Message-----
> >> From: linux-kernel-owner@...r.kernel.org [mailto:linux-kernel-
> >> owner@...r.kernel.org] On Behalf Of Jisheng Zhang
> >> Sent: 16 March 2016 11:41
> >> To: jingoohan1@...il.com; pratyush.anand@...il.com;
> bhelgaas@...gle.com
> >> Cc: linux-pci@...r.kernel.org; linux-kernel@...r.kernel.org; linux-
> arm-
> >> kernel@...ts.infradead.org; Jisheng Zhang
> >> Subject: [PATCH v2] PCI: designware: move remaining rc setup code to
> >> dw_pcie_setup_rc()
> >>
> >> dw_pcie_setup_rc(), as its name indicates, setups the RC. But
> current
> >> dw_pcie_host_init() also contains some necessary rc setup code.
> >>
> >> Another reason: the host may lost power during suspend to ram, the
> RC
> >> need to be re-setup after resume. The rc can't be correctly resumed
> >> without the rc setup code in dw_pcie_host_init().
> >>
> >> So this patch moves the code to dw_pcie_setup_rc() to address the
> above
> >> two issues. After this patch, each pcie designware driver users
> could
> >> call dw_pcie_setup_rc() to re-setup rc when resume back.
> >
> > I think this patch breaks the Hisilicon driver...
> >
> > Our driver performs linkup setup in UEFI therefore we do not call
> > dw_pcie_setup_rc(), we only call dw_pcie_host_init().
> >
> > Maybe better to group the part of code to be moved in as separate
> > function...
> >
> > Thanks and sorry for late reply.
> >
> 
> I am just wondering, should n't then what ever we do in
> dw_pcie_setup_rc() be done in your boot loader and not just link up.

Currently the HiSilicon driver does not call dw_pcie_setup_rc() at all;
so everything is done in dw_pcie_setup_rc() is done in bootloader.

I guess your question is if we can execute in bootloader the part of
code the this patch has moved to in "dw_pcie_setup_rc()". I think the
problem here is that even if it was possible we would break backward
compatibility with previous bootloaders...

Thanks

Gab 


> 
> ~Pratyush