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From: Vinod Koul <vkoul@kernel.org>
To: linux-phy@lists.infradead.org, Marcel Ziswiler <marcel@ziswiler.com>
Cc: linux-imx@nxp.com, linux-kernel@vger.kernel.org, kernel@pengutronix.de, 
 Richard Zhu <hongxing.zhu@nxp.com>, Lucas Stach <l.stach@pengutronix.de>, 
 linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org, 
 Marcel Ziswiler <marcel.ziswiler@toradex.com>, 
 Fabio Estevam <festevam@gmail.com>, Heiko Stuebner <heiko@sntech.de>, 
 Kishon Vijay Abraham I <kishon@kernel.org>, Rob Herring <robh@kernel.org>, 
 Sascha Hauer <s.hauer@pengutronix.de>, 
 Sergio Paracuellos <sergio.paracuellos@gmail.com>, 
 Shawn Guo <shawnguo@kernel.org>, Tim Harvey <tharvey@gateworks.com>, 
 Yang Li <yang.lee@linux.alibaba.com>, imx@lists.linux.dev
In-Reply-To: <20240327071946.8869-1-marcel@ziswiler.com>
References: <20240327071946.8869-1-marcel@ziswiler.com>
Subject: Re: [PATCH v2] phy: freescale: imx8m-pcie: fix pcie link-up
 instability
Message-Id: <171239512402.352254.17030670986383011631.b4-ty@kernel.org>
Date: Sat, 06 Apr 2024 14:48:44 +0530
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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