From mboxrd@z Thu Jan  1 00:00:00 1970
From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi)
Date: Mon, 17 Sep 2018 11:13:53 +0100
Subject: [PATCH 0/2] Workaround for IMX7d PCI-e PLL lock failure
In-Reply-To: <20180718194424.8844-1-tpiepho@impinj.com>
References: <20180718194424.8844-1-tpiepho@impinj.com>
Message-ID: <20180917101353.GA7239@e107981-ln.cambridge.arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Wed, Jul 18, 2018 at 12:44:22PM -0700, Trent Piepho wrote:
> This is the workaround for the IMX7d Erratum e10728, failure of
> initialize PCIe PLL VCO oscillation resulting in PLL lock failure and
> failure of the PCI-e link to come up.
> 
> The registers used in the workaround are based on the latest patch in
> the NXP kernel, but many things around that have been changed.
> 
> This uses a new node of type fsl,imx-pcie-phy to get the PHY's
> registers.  The node is found via a phandle added to the PCI-e
> controller's node, rather than the incorrect way done in the NXP kernel.
> 
> There is no error if the phandle is not preset (since it's needed except
> for the imx7d workaround and no existing dtses have it), but if preset
> it is an error if something relating to it does not work.
> 
> ** Should the node be fsl,imx7d-pcie-phy?  snps,dw-pcie-phy?  
> 
> There is little to no documenation from NXP and Synopsis about this, so I'm
> unsure of the PHY's lineage.
> 
> The imx6 PCI-e driver does not use the generic phy layer to interact
> with the PHY.  It appears PHY related hardware, like clocks, regulators,
> and resets, are part of the fsl,imx6q-pcie node.  But again, the
> topology of this hardware is not documented very well.
> 
> Another approach would be to add the PHY registers as another bank in
> the PCI-e node.  This would match how the PHY reset, clock, etc.  are
> done.  However, the PHY is attached to a different AXI master than the
> PCI-e controller, so the register range really does not belong there.
> 
> Trent Piepho (2):
>   ARM: dts: imx7d: Add node for PCIe PHY
>   PCI: imx: Add workaround for e10728, IMX7d PCIe PLL failure

Marked as "changes requested", following Lucas' review, please
respin as appropriate.

Lorenzo

>  .../devicetree/bindings/pci/fsl,imx6q-pcie.txt     | 11 ++++
>  arch/arm/boot/dts/imx7d.dtsi                       |  9 ++++
>  drivers/pci/dwc/pci-imx6.c                         | 59 ++++++++++++++++++++++
>  3 files changed, 79 insertions(+)
> 
> Cc: Shawn Guo <shawnguo@kernel.org>
> Cc: Sascha Hauer <kernel@pengutronix.de>
> Cc: Fabio Estevam <fabio.estevam@nxp.com>
> Cc: Richard Zhu <hongxing.zhu@nxp.com>
> Cc: Lucas Stach <l.stach@pengutronix.de>
> 
> -- 
> 2.14.4
> 
>