From: Baruch Siach <baruch@tkos.co.il>
To: Andrew Lunn <andrew@lunn.ch>
Cc: linux-pwm@vger.kernel.org,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Sven Auhagen <sven.auhagen@voleatech.de>,
Jason Cooper <jason@lakedaemon.net>,
linux-gpio@vger.kernel.org, linux-pci@vger.kernel.org,
Linus Walleij <linus.walleij@linaro.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Thierry Reding <thierry.reding@gmail.com>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Gregory Clement <gregory.clement@bootlin.com>,
linux-arm-kernel@lists.infradead.org,
Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Subject: Re: [PATCH 2/2] PCI: armada8k: don't toggle reset twice
Date: Thu, 10 Jan 2019 15:05:49 +0200 [thread overview]
Message-ID: <8736q0irwy.fsf@tarshish> (raw)
In-Reply-To: <20190110125548.GA29612@lunn.ch>
Hi Andrew,
On Thu, Jan 10 2019, Andrew Lunn wrote:
> On Thu, Jan 10, 2019 at 02:26:22PM +0200, Baruch Siach wrote:
>> Commit 3d71746c42 ("PCI: armada8k: Add support for gpio controlled reset
>> signal") added reset signal support. Reset is unconditionally asserted
>> and deasserted.
>>
>> Unfortunately, that commit breaks boot on Macchiatobin when a Mellanox
>> NIC is in the PCIe slot.
>>
>> It turns out that you can toggle the reset signal only once. Another
>> reset signal toggle makes access to PCI configuration registers stall
>> indefinitely. U-Boot toggles the Macchiatobin PCIe reset line already at
>> boot.
>
> Hi Baruch
>
> Is this double reset issue limited to just Mellanox NICs, or any
> device in the PCIe slot?
>
> This sounds more like a workaround than a fix. It would be good to
> investigate further and determine which end of the PCIe link has the
> problem.
Sven Auhagen reported the same issue with Intel NIC attached to
mini-PCIe slots on a custom Armada 8K design.
How would you suggest to investigate this issue?
baruch
--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- baruch@tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -
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next prev parent reply other threads:[~2019-01-10 13:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-10 12:26 [PATCH 1/2] gpio: mvebu: implement get_direction Baruch Siach
2019-01-10 12:26 ` [PATCH 2/2] PCI: armada8k: don't toggle reset twice Baruch Siach
2019-01-10 12:55 ` Andrew Lunn
2019-01-10 13:05 ` Baruch Siach [this message]
2019-01-10 13:19 ` Andrew Lunn
2019-01-10 15:57 ` Baruch Siach
2019-01-13 12:38 ` Baruch Siach
2019-01-13 15:40 ` Andrew Lunn
2019-01-13 18:42 ` Baruch Siach
2019-01-13 23:35 ` Linus Walleij
2019-01-14 7:19 ` Baruch Siach
2019-01-10 15:20 ` [PATCH 1/2] gpio: mvebu: implement get_direction Linus Walleij
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