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Date:   Wed, 13 Apr 2022 21:22:07 +0300
From:   Vladimir Oltean <olteanv@gmail.com>
To:     Leo Li <leoyang.li@nxp.com>
Cc:     "Z.Q. Hou" <zhiqiang.hou@nxp.com>, Shawn Guo <shawnguo@kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Xiaowei Bao <xiaowei.bao@nxp.com>
Subject: Re: [PATCH v3 1/8] arm64: dts: ls1028a: Add PCIe EP nodes
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On Wed, Apr 13, 2022 at 06:03:37PM +0000, Leo Li wrote:
> > arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi:631.23-656.5: Warning
> > (unique_unit_address): /soc/pcie@3400000: duplicate unit-address (also
> > used in node /soc/pcie-ep@3400000)
> > arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi:670.23-695.5: Warning
> > (unique_unit_address): /soc/pcie@3500000: duplicate unit-address (also
> > used in node /soc/pcie-ep@3500000)
> 
> This would be a common problem for all the layerscape PCIe controller.
> The controller can either work in RC mode or EP mode.  The current
> binding of the controller defined two compatibles, one for RC and one
> for EP.  Therefore the SoC dtsi will have two nodes with the same unit
> address one for EP one for RC.  Fixing this probably requires
> comprehensive updates to the binding which breaks backward
> compatibility.

So we have to live with these warnings forever now?

How are the PCIe controllers configured for RC or EP mode? Via RCW?
Is dynamic configuration possible?

Can't U-Boot detect the operating mode from the RCW and fix up the
compatible string in case the controller is in endpoint mode?