From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baruch Siach Subject: Re: [PATCH 2/2] PCI: armada8k: don't toggle reset twice Date: Thu, 10 Jan 2019 15:05:49 +0200 Message-ID: <8736q0irwy.fsf@tarshish> References: <024cc24efa7b99186750f90c91880b29357d379d.1547123182.git.baruch@tkos.co.il> <94cd23a60c647020dd87a923684b59255b89f02c.1547123182.git.baruch@tkos.co.il> <20190110125548.GA29612@lunn.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <20190110125548.GA29612@lunn.ch> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Andrew Lunn Cc: linux-pwm@vger.kernel.org, Lorenzo Pieralisi , Sven Auhagen , Jason Cooper , linux-gpio@vger.kernel.org, linux-pci@vger.kernel.org, Linus Walleij , Bartosz Golaszewski , Thierry Reding , Thomas Petazzoni , Bjorn Helgaas , Gregory Clement , linux-arm-kernel@lists.infradead.org, Sebastian Hesselbarth List-Id: linux-gpio@vger.kernel.org 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 -