Re: [PATCH V5 5/5] PCI: tegra: Add support for PCIe endpoint mode in Tegra194

From: Bjorn Helgaas <bjorn.helgaas@gmail.com>
To: Vidya Sagar <vidyas@nvidia.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	robh+dt@kernel.org, thierry.reding@gmail.com,
	jonathanh@nvidia.com, Andrew Murray <andrew.murray@arm.com>,
	kishon@ti.com, gustavo.pimentel@synopsys.com,
	linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
	linux-tegra@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	ARM <linux-arm-kernel@lists.infradead.org>,
	kthota@nvidia.com, mmaddireddy@nvidia.com, sagar.tv@gmail.com
Subject: Re: [PATCH V5 5/5] PCI: tegra: Add support for PCIe endpoint mode in Tegra194
Date: Mon, 30 Mar 2020 22:00:57 -0500	[thread overview]
Message-ID: <CABhMZUXub++CLTJ_E88Jwar5RvVfL+3aWOHqZf5XSVeyS8X=wA@mail.gmail.com> (raw)
In-Reply-To: <bba72560-85cc-b59b-b0e8-bfc7c7408736@nvidia.com>

On Mon, Mar 30, 2020 at 9:55 PM Vidya Sagar <vidyas@nvidia.com> wrote:
>
>
>
> On 3/31/2020 3:17 AM, Bjorn Helgaas wrote:
> > External email: Use caution opening links or attachments
> >
> >
> > On Tue, Mar 03, 2020 at 11:40:52PM +0530, Vidya Sagar wrote:
> >> Add support for the endpoint mode of Synopsys DesignWare core based
> >> dual mode PCIe controllers present in Tegra194 SoC.
> >>
> >> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> >> Acked-by: Thierry Reding <treding@nvidia.com>
> >> ---
> >> V5:
> >> * Added Acked-by: Thierry Reding <treding@nvidia.com>
> >> * Removed unwanted header file inclusion
> >>
> >> V4:
> >> * Addressed Lorenzo's review comments
> >> * Started using threaded irqs instead of kthreads
> >>
> >> V3:
> >> * Addressed Thierry's review comments
> >>
> >> V2:
> >> * Addressed Bjorn's review comments
> >> * Made changes as part of addressing review comments for other patches
> >>
> >>   drivers/pci/controller/dwc/Kconfig         |  30 +-
> >>   drivers/pci/controller/dwc/pcie-tegra194.c | 679 ++++++++++++++++++++-
> >>   2 files changed, 691 insertions(+), 18 deletions(-)
> >>
> >> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> >> index 0830dfcfa43a..169cde58dd92 100644
> >> --- a/drivers/pci/controller/dwc/Kconfig
> >> +++ b/drivers/pci/controller/dwc/Kconfig
> >> @@ -248,14 +248,38 @@ config PCI_MESON
> >>          implement the driver.
> >>
> >>   config PCIE_TEGRA194
> >> -     tristate "NVIDIA Tegra194 (and later) PCIe controller"
> >> +     tristate
> >> +
> >> +config PCIE_TEGRA194_HOST
> >> +     tristate "NVIDIA Tegra194 (and later) PCIe controller - Host Mode"
> >>        depends on ARCH_TEGRA_194_SOC || COMPILE_TEST
> >>        depends on PCI_MSI_IRQ_DOMAIN
> >>        select PCIE_DW_HOST
> >>        select PHY_TEGRA194_P2U
> >> +     select PCIE_TEGRA194
> >> +     default y
> >
> > Sorry I missed this before, but why is this "default y"?  From
> > Documentation/kbuild/kconfig-language.rst:
> >
> >    The default value deliberately defaults to 'n' in order to avoid
> >    bloating the build. With few exceptions, new config options should
> >    not change this. The intent is for "make oldconfig" to add as little
> >    as possible to the config from release to release.
> >
> > I do see that several other things in other drivers/pci/ Kconfig files
> > are also "default y", and we should probably change some of them.  But
> > I don't want to add even more unless there's a good reason.
> >
> > I'm not looking for more reactions like these:
> >
> > https://lore.kernel.org/r/CAHk-=wiZ24JuVehJ5sEC0UG1Gk2nvB363wO02RRsR1oEht6R9Q@mail.gmail.com
> > https://lore.kernel.org/r/CA+55aFzPpuHU1Nqd595SEQS=F+kXMzPs0Rba9FUgTodGxmXsgg@mail.gmail.com
> >
> > Can you please update this patch to either remove the "default y" or
> > add the rationale for keeping it?
> I'm fine with removing 'default y' line.
> Should I send a patch only with this change?

I think it's probably just as easy for Lorenzo to delete that line on
his branch.  If not, I'll cherry-pick the patches on that branch and
do it locally.

Bjorn