From: Rob Herring <robh@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: linux-pci@vger.kernel.org, linux-amlogic@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Kevin Hilman <khilman@baylibre.com>,
Yue Wang <yue.wang@Amlogic.com>
Subject: Re: [PATCH] PCI: amlogic: meson: Don't use FAST_LINK_MODE to set up link
Date: Thu, 7 May 2020 16:03:15 -0500 [thread overview]
Message-ID: <20200507210315.GA19547@bogus> (raw)
In-Reply-To: <20200429164230.309922-1-maz@kernel.org>
On Wed, 29 Apr 2020 17:42:30 +0100, Marc Zyngier wrote:
> My vim3l board stubbornly refuses to play ball with a bog
> standard PCIe switch (ASM1184e), spitting all kind of errors
> ranging from link never coming up to crazy things like downstream
> ports falling off the face of the planet.
>
> Upon investigating how the PCIe RC is configured, I found the
> following nugget: the Sysnopsys DWC PCIe Reference Manual, in the
> section dedicated to the PLCR register, describes bit 7 (FAST_LINK_MODE)
> as:
>
> "Sets all internal timers to fast mode for simulation purposes."
>
> I completely understand the need for setting this bit from a simulation
> perspective, but what I have on my desk is actual silicon, which
> expects timers to have a nominal value (and I expect this is the
> case for most people).
>
> Making sure the FAST_LINK_MODE bit is cleared when configuring the RC
> solves this problem.
>
> Fixes: 9c0ef6d34fdb ("PCI: amlogic: Add the Amlogic Meson PCIe controller driver")
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
> drivers/pci/controller/dwc/pci-meson.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
Acked-by: Rob Herring <robh@kernel.org>
next prev parent reply other threads:[~2020-05-07 21:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-29 16:42 [PATCH] PCI: amlogic: meson: Don't use FAST_LINK_MODE to set up link Marc Zyngier
2020-05-06 10:43 ` Marc Zyngier
2020-05-07 21:03 ` Rob Herring [this message]
[not found] ` <2020050709433087691414@amlogic.com>
2020-05-09 13:07 ` Marc Zyngier
2020-05-11 8:58 ` Neil Armstrong
2020-05-11 10:22 ` Lorenzo Pieralisi
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