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Subject: Re: [PATCH v3 0/6] PCI: J7200/J721E PCIe bindings
To:     Nishanth Menon <nm@ti.com>
CC:     Rob Herring <robh+dt@kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20210104122232.24071-1-kishon@ti.com>
 <20210104125910.qaf7vi3dx6vsne6t@backfield>
 <465097c1-2d38-ad45-cc32-d92c385114c5@ti.com>
 <20210104131642.m5rgpkhnrffq5nrx@circular>
From:   Kishon Vijay Abraham I <kishon@ti.com>
Message-ID: <d50fa957-7371-090a-754c-816760b43a27@ti.com>
Date:   Mon, 4 Jan 2021 18:52:03 +0530
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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.

Thanks
Kishon