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Date:   Mon, 4 Jan 2021 08:51:37 -0600
From:   Nishanth Menon <nm@ti.com>
To:     Kishon Vijay Abraham I <kishon@ti.com>
CC:     Rob Herring <robh+dt@kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 0/6] PCI: J7200/J721E PCIe bindings
Message-ID: <20210104145137.wmtppcvjzu374yly@kahuna>
References: <20210104122232.24071-1-kishon@ti.com>
 <20210104125910.qaf7vi3dx6vsne6t@backfield>
 <465097c1-2d38-ad45-cc32-d92c385114c5@ti.com>
 <20210104131642.m5rgpkhnrffq5nrx@circular>
 <d50fa957-7371-090a-754c-816760b43a27@ti.com>
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On 18:52-20210104, Kishon Vijay Abraham I wrote:
> Nishanth,
> 
> On 04/01/21 6:46 pm, Nishanth Menon wrote:
> > On 18:40-20210104, Kishon Vijay Abraham I wrote:
> >> Nishanth,
> >>
> >> On 04/01/21 6:29 pm, Nishanth Menon wrote:
> >>> On 17:52-20210104, Kishon Vijay Abraham I wrote:
> >>>> Patch series adds DT nodes in order to get PCIe working in J7200.
> >>>> Also includes couple of fixes for J721e.
> >>>>
> >>>> v1 of the patch series can be found @ [1]
> >>>> v2 of the patch series can be found @ [2]
> >>>>
> >>>> Changes from v2:
> >>>> 1) Moved serdes_refclk node out of interconnect node and also replaced
> >>>>    "_" with "-"
> >>>>
> >>>> Changes from v1:
> >>>> 1) Include only the device tree patches here (the binding patch is sent
> >>>> separately)
> >>>> 2) Include couple of patches that fixes J721E DTS.
> >>>>
> >>>> [1] -> http://lore.kernel.org/r/20201102101154.13598-1-kishon@ti.com
> >>>> [2] -> http://lore.kernel.org/r/20201210130747.25436-1-kishon@ti.com
> >>>>
> >>>> Kishon Vijay Abraham I (6):
> >>>>   arm64: dts: ti: k3-j721e-main: Fix supported max outbound regions
> >>>>   arm64: dts: ti: k3-j721e-main: Remove "syscon" nodes added for
> >>>>     pcieX_ctrl
> >>>>   arm64: dts: ti: k3-j7200-main: Add SERDES and WIZ device tree node
> >>>>   arm64: dts: ti: k3-j7200-main: Add PCIe device tree node
> >>>>   arm64: dts: ti: k3-j7200-common-proc-board: Enable SERDES0
> >>>>   arm64: dts: ti: k3-j7200-common-proc-board: Enable PCIe
> >>>>
> >>>>  .../dts/ti/k3-j7200-common-proc-board.dts     |  38 ++++++
> >>>>  arch/arm64/boot/dts/ti/k3-j7200-main.dtsi     | 111 ++++++++++++++++++
> >>>>  arch/arm64/boot/dts/ti/k3-j721e-main.dtsi     |  52 ++------
> >>>>  3 files changed, 157 insertions(+), 44 deletions(-)
> >>>
> >>>
> >>> A bit confused on the dependency here. is there something merged into
> >>> next-20210104 that makes this series ready for pickup? is there a way
> >>> I can get a immutable tag for driver fixups to pull so that my dts
> >>> next is not broken for PCIe (I am assuming looking at the series that
> >>> this is probably not a backward compatible series?)?
> >>
> >> There are no driver changes for the basic J7200 PCIe support and the DT
> >> bindings are already merged [1].
> >>
> >> There are few errata fixes applicable for J721E which has to be removed
> >> for J7200 but that depends on other patches to be merged [1] but that
> >> doesn't impact j7200 functionality.
> >>
> >> [1] ->
> >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/pci/ti,j721e-pci-host.yaml#n19
> >> [2] -> http://lore.kernel.org/r/20201230120515.2348-1-nadeem@cadence.com
> > 
> > So, Dropping stuff like "cdns,max-outbound-regions" (change from 16 to
> > 32) will work on older kernels? Could you do a quick sanity check on the
> > couple of "fixes" patches in this thread is not breaking functionality
> > introduced in the older stable kernels?
> 
> Okay, the driver changes are done such that it works with both old DT
> and new DT however the newer DT will not work with old kernel. So I
> think I should drop the "Fixes" tag in the DT patches.

If there is a specific stable kernel version you might like to use, you
could use that as well for those stable tags (see [1])


[1] https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D