From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH v3 00/15] Bring suspend to RAM support to PCIe Aardvark driver Date: Fri, 25 Jan 2019 12:40:11 +0000 Message-ID: <20190125124011.GA16389@e107981-ln.cambridge.arm.com> References: <20190108162441.5278-1-miquel.raynal@bootlin.com> <20190123170509.GB1157@e107981-ln.cambridge.arm.com> <20190125110530.0ff11a54@xps13> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190125110530.0ff11a54@xps13> Sender: linux-kernel-owner@vger.kernel.org To: Miquel Raynal Cc: Gregory Clement , Jason Cooper , Andrew Lunn , Sebastian Hesselbarth , Thomas Petazzoni , Bjorn Helgaas , devicetree@vger.kernel.org, Rob Herring , Mark Rutland , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Antoine Tenart , Maxime Chevallier , Nadav Haklai List-Id: devicetree@vger.kernel.org On Fri, Jan 25, 2019 at 11:05:30AM +0100, Miquel Raynal wrote: > Hi Lorenzo, > > Lorenzo Pieralisi wrote on Wed, 23 Jan 2019 > 17:05:09 +0000: > > > On Tue, Jan 08, 2019 at 05:24:25PM +0100, Miquel Raynal wrote: > > > Hello, > > > > > > As part of an effort to bring suspend to RAM support to Armada 3700 > > > SoCs (main target: ESPRESSObin), this series handles the work around > > > the PCIe IP. > > > > > > First, more configuration is done in the 'setup' helper as inspired > > > from the U-Boot driver. This is needed to entirely initialize the IP > > > during future resume operation (patch 1). > > > > > > Then, reset GPIO, PHY and clock support are introduced (patch 2-4). As > > > current device trees do not provide the corresponding properties, not > > > finding one of these properties is not an error and just produces a > > > warning. However, if the property is present, an error during PHY > > > initialization will fail the probe of the driver. > > > > > > Note: To be sure the clock will be resumed before this driver, a first > > > series adding links between clocks and consumers has been submitted, > > > see [1]. Anyway, having the clock series applied first is not needed. > > > > I do not understand what this means, in particular in relation > > to the blocking clock calls in the suspend/resume NOIRQ hooks. > > I am not sure to understand your question. > > As there are multiple points in this sentence I will detail each of > them so please comment on the one which is bothering you: > * I am working in parallel on a series adding device links to the clock > framework. This way when a driver consumes a clock, the clock > provider driver will be resumed first. > * If the clock series I am talking about is applied after this one, > there is no build issue. Of course suspending the platform may > not work but this is a new feature so nothing will be broken. Suspend to RAM will be broken if the clock is suspended and no notification will happen in the NOIRQ phase, it is a new-broken-feature. > * Device links do not enforce any priority if the suspend/resume phase > between two drivers is not the same. The PCIe driver suspends in the > NOIRQ phase. If we want the clock driver to suspend *after* PCIe, its > suspend/resume callbacks must be promoted to the NOIRQ phase as well > (and this is part of another series). As of today there is > no alternative. I will merge this series when it works, I have no evidence that it does given what you are writing above, if the series you mention are *necessary* for suspend-to-RAM to work they ought to be merged first. Thanks, Lorenzo