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Message-Id: <171239512402.352254.17030670986383011631.b4-ty@kernel.org>
Date: Sat, 06 Apr 2024 14:48:44 +0530
From: Vinod Koul <vkoul@...nel.org>
To: linux-phy@...ts.infradead.org, Marcel Ziswiler <marcel@...wiler.com>
Cc: linux-imx@....com, linux-kernel@...r.kernel.org, kernel@...gutronix.de,
Richard Zhu <hongxing.zhu@....com>, Lucas Stach <l.stach@...gutronix.de>,
linux-arm-kernel@...ts.infradead.org, stable@...r.kernel.org,
Marcel Ziswiler <marcel.ziswiler@...adex.com>,
Fabio Estevam <festevam@...il.com>, Heiko Stuebner <heiko@...ech.de>,
Kishon Vijay Abraham I <kishon@...nel.org>, Rob Herring <robh@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Sergio Paracuellos <sergio.paracuellos@...il.com>,
Shawn Guo <shawnguo@...nel.org>, Tim Harvey <tharvey@...eworks.com>,
Yang Li <yang.lee@...ux.alibaba.com>, imx@...ts.linux.dev
Subject: Re: [PATCH v2] phy: freescale: imx8m-pcie: fix pcie link-up
instability
On Wed, 27 Mar 2024 08:19:37 +0100, Marcel Ziswiler wrote:
> On the i.MX 8M Mini, the AUX_PLL_REFCLK_SEL has to be left at its reset
> default of AUX_IN (PLL clock).
>
> Background Information:
> In our automated testing setup, we use Delock Mini-PCIe SATA cards [1].
> While this setup has proven very stable overall we noticed upstream on
> the i.MX 8M Mini fails quite regularly (about 50/50) to bring up the
> PCIe link while with NXP's downstream BSP 5.15.71_2.2.2 it always works.
> As that old downstream stuff was quite different, I first also tried
> NXP's latest downstream BSP 6.1.55_2.2.0 which from a PCIe point of view
> is fairly vanilla, however, also there the PCIe link-up was not stable.
> Comparing and debugging I noticed that upstream explicitly configures
> the AUX_PLL_REFCLK_SEL to I_PLL_REFCLK_FROM_SYSPLL while working
> downstream [2] leaving it at reset defaults of AUX_IN (PLL clock).
> Unfortunately, the TRM does not mention any further details about this
> register (both for the i.MX 8M Mini as well as the Plus).
> NXP confirmed their validation codes for the i.MX8MM PCIe doesn't
> configure cmn_reg063 (offset: 0x18C).
> BTW: On the i.MX 8M Plus we have not seen any issues with PCIe with the
> exact same setup which is why I left it unchanged.
>
> [...]
Applied, thanks!
[1/1] phy: freescale: imx8m-pcie: fix pcie link-up instability
commit: 3a161017f1de55cc48be81f6156004c151f32677
Best regards,
--
~Vinod
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