From: Marek Vasut <marek.vasut@gmail.com>
To: Sasha Levin <sashal@kernel.org>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Marek Vasut <marek.vasut+renesas@gmail.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Wolfram Sang <wsa@the-dreams.de>,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
linux-renesas-soc@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH AUTOSEL 5.14 12/32] PCI: rcar: Add L1 link state fix into data abort hook
Date: Sat, 11 Sep 2021 18:05:37 +0200 [thread overview]
Message-ID: <6cbfadee-0d74-fa4c-9ef3-a1bce55632bb@gmail.com> (raw)
In-Reply-To: <20210911131149.284397-12-sashal@kernel.org>
On 9/11/21 3:11 PM, Sasha Levin wrote:
> From: Marek Vasut <marek.vasut+renesas@gmail.com>
>
> [ Upstream commit a115b1bd3af0c2963e72f6e47143724c59251be6 ]
>
> When the link is in L1, hardware should return it to L0
> automatically whenever a transaction targets a component on the
> other end of the link (PCIe r5.0, sec 5.2).
>
> The R-Car PCIe controller doesn't handle this transition correctly.
> If the link is not in L0, an MMIO transaction targeting a downstream
> device fails, and the controller reports an ARM imprecise external
> abort.
>
> Work around this by hooking the abort handler so the driver can
> detect this situation and help the hardware complete the link state
> transition.
>
> When the R-Car controller receives a PM_ENTER_L1 DLLP from the
> downstream component, it sets PMEL1RX bit in PMSR register, but then
> the controller enters some sort of in-between state. A subsequent
> MMIO transaction will fail, resulting in the external abort. The
> abort handler detects this condition and completes the link state
> transition by setting the L1IATN bit in PMCTLR and waiting for the
> link state transition to complete.
You will also need the following patch, otherwise the build will fail on
configurations without COMMON_CLK (none where this driver is used, but
happened on one of the build bots). I'm waiting for PCIe maintainers to
pick it up:
https://patchwork.kernel.org/project/linux-pci/patch/20210907144512.5238-1-marek.vasut@gmail.com/
next prev parent reply other threads:[~2021-09-11 16:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210911131149.284397-1-sashal@kernel.org>
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 04/32] PCI: Add ACS quirks for NXP LX2xx0 and LX2xx2 platforms Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 06/32] PCI: tegra194: Fix handling BME_CHGED event Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 07/32] PCI: tegra194: Fix MSI-X programming Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 08/32] PCI: tegra: Fix OF node reference leak Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 10/32] PCI: rcar: Fix runtime PM imbalance in rcar_pcie_ep_probe() Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 12/32] PCI: rcar: Add L1 link state fix into data abort hook Sasha Levin
2021-09-11 16:05 ` Marek Vasut [this message]
2021-09-20 12:12 ` Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 15/32] PCI: cadence: Use bitfield for *quirk_retrain_flag* instead of bool Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 16/32] PCI: cadence: Add quirk flag to set minimum delay in LTSSM Detect.Quiet state Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 17/32] PCI: j721e: Add PCIe support for J7200 Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 18/32] PCI: j721e: Add PCIe support for AM64 Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 19/32] PCI: Add ACS quirks for Cavium multi-function devices Sasha Levin
2021-09-11 13:11 ` [PATCH AUTOSEL 5.14 26/32] PCI: ibmphp: Fix double unmap of io_mem Sasha Levin
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