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From: Andrew Lunn <andrew@lunn.ch>
To: Baruch Siach <baruch@tkos.co.il>
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 13:55:48 +0100	[thread overview]
Message-ID: <20190110125548.GA29612@lunn.ch> (raw)
In-Reply-To: <94cd23a60c647020dd87a923684b59255b89f02c.1547123182.git.baruch@tkos.co.il>

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.

Thanks
	Andrew

WARNING: multiple messages have this Message-ID (diff)
From: Andrew Lunn <andrew@lunn.ch>
To: Baruch Siach <baruch@tkos.co.il>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Sven Auhagen <sven.auhagen@voleatech.de>,
	linux-pwm@vger.kernel.org, linux-gpio@vger.kernel.org,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	Jason Cooper <jason@lakedaemon.net>,
	Gregory Clement <gregory.clement@bootlin.com>,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Subject: Re: [PATCH 2/2] PCI: armada8k: don't toggle reset twice
Date: Thu, 10 Jan 2019 13:55:48 +0100	[thread overview]
Message-ID: <20190110125548.GA29612@lunn.ch> (raw)
In-Reply-To: <94cd23a60c647020dd87a923684b59255b89f02c.1547123182.git.baruch@tkos.co.il>

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.

Thanks
	Andrew

WARNING: multiple messages have this Message-ID (diff)
From: Andrew Lunn <andrew@lunn.ch>
To: Baruch Siach <baruch@tkos.co.il>
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 13:55:48 +0100	[thread overview]
Message-ID: <20190110125548.GA29612@lunn.ch> (raw)
In-Reply-To: <94cd23a60c647020dd87a923684b59255b89f02c.1547123182.git.baruch@tkos.co.il>

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.

Thanks
	Andrew

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2019-01-10 12:55 UTC|newest]

Thread overview: 36+ 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 ` Baruch Siach
2019-01-10 12:26 ` Baruch Siach
2019-01-10 12:26 ` [PATCH 2/2] PCI: armada8k: don't toggle reset twice Baruch Siach
2019-01-10 12:26   ` Baruch Siach
2019-01-10 12:26   ` Baruch Siach
2019-01-10 12:55   ` Andrew Lunn [this message]
2019-01-10 12:55     ` Andrew Lunn
2019-01-10 12:55     ` Andrew Lunn
2019-01-10 13:05     ` Baruch Siach
2019-01-10 13:05       ` Baruch Siach
2019-01-10 13:05       ` Baruch Siach
2019-01-10 13:19       ` Andrew Lunn
2019-01-10 13:19         ` Andrew Lunn
2019-01-10 13:19         ` Andrew Lunn
2019-01-10 15:57         ` Baruch Siach
2019-01-10 15:57           ` Baruch Siach
2019-01-10 15:57           ` Baruch Siach
2019-01-13 12:38           ` Baruch Siach
2019-01-13 12:38             ` Baruch Siach
2019-01-13 12:38             ` Baruch Siach
2019-01-13 15:40             ` Andrew Lunn
2019-01-13 15:40               ` Andrew Lunn
2019-01-13 15:40               ` Andrew Lunn
2019-01-13 18:42               ` Baruch Siach
2019-01-13 18:42                 ` Baruch Siach
2019-01-13 18:42                 ` Baruch Siach
2019-01-13 23:35               ` Linus Walleij
2019-01-13 23:35                 ` Linus Walleij
2019-01-13 23:35                 ` Linus Walleij
2019-01-14  7:19                 ` Baruch Siach
2019-01-14  7:19                   ` Baruch Siach
2019-01-14  7:19                   ` Baruch Siach
2019-01-10 15:20 ` [PATCH 1/2] gpio: mvebu: implement get_direction Linus Walleij
2019-01-10 15:20   ` Linus Walleij
2019-01-10 15:20   ` Linus Walleij

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