From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v3 3/5] PCI: st: Provide support for the sti PCIe controller
Date: Sat, 11 Apr 2015 16:55:50 +0200
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To: Paul Bolle <pebolle@tiscali.nl>
Cc: Gabriel FERNANDEZ <gabriel.fernandez@st.com>, Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>, Mark Rutland <mark.rutland@arm.com>, Ian Campbell <ijc+devicetree@hellion.org.uk>, Kumar Gala <galak@codeaurora.org>, Srinivas Kandagatla <srinivas.kandagatla@gmail.com>, Maxime Coquelin <maxime.coquelin@st.com>, Patrice Chotard <patrice.chotard@st.com>, Russell King <linux@arm.linux.org.uk>, Bjorn Helgaas <bhelgaas@google.com>, Jingoo Han <jg1.han@samsung.com>, Lucas Stach <l.stach@pengutronix.de>, Fabrice Gasnier <fabrice.gasnier@st.com>, Kishon Vijay Abraham I <kishon@ti.com>, Andrew Morton <akpm@linux-foundation.org>, "David S. Miller" <davem@davemloft.net>, Greg KH <gregkh@linuxfoundation.org>, Mauro Carvalho Chehab <mchehab@osg.samsung.com>, Joe Perches <joe@perches.com>, Tejun Heo <tj@kernel.org>, Viresh Kumar <viresh.kumar@linaro.org>, Thierry
List-Id: devicetree@vger.kernel.org

On Saturday 11 April 2015 12:17:57 Paul Bolle wrote:
> Something I didn't spot in my first look at this patch.
> 
> On Fri, 2015-04-10 at 11:12 +0200, Gabriel FERNANDEZ wrote:
> > --- a/drivers/pci/host/Kconfig
> > +++ b/drivers/pci/host/Kconfig
> >  
> > +config PCI_ST
> > +     bool "ST PCIe controller"
> > +     depends on ARCH_STI || (ARM && COMPILE_TEST)
> > +     select PCIE_DW
> > +     help
> > +       Enable PCIe controller support on ST Socs. This controller is based
> > +       on Designware hardware and therefore the driver re-uses the
> > +       Designware core functions to implement the driver.
> 
> You can't have ARCH_STI without ARM, so ARM will always be set if this
> driver is enabled. Correct?

Right, though the ARM dependency could soon be dropped, once the PCIE_DW
driver can use generic infrastructure in the few places it relies on
ARM specific code today.

> > --- /dev/null
> > +++ b/drivers/pci/host/pci-st.c
> 
> > +     if (IS_ENABLED(CONFIG_ARM)) {
> > +             /*
> > +              * We have to hook the abort handler so that we can intercept
> > +              * bus errors when doing config read/write that return UR,
> > +              * which is flagged up as a bus error
> > +              */
> > +             hook_fault_code(16+6, st_pcie_abort_handler, SIGBUS, 0,
> > +                             "imprecise external abort");
> > +     }
> 
> So, unless I'm missing something obvious here, IS_ENABLED(CONFIG_ARM)
> will always evaluate to 1. Can't that test be dropped?

I would leave it in, as it's quite likely to get reused with ARM64 at some
point in the future (no, I don't know anything about ST's product plans,
but everybody seems to be doing this).

	Arnd