From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 05/12] PCI: aardvark: add suspend to RAM support Date: Mon, 03 Dec 2018 23:00:20 +0100 Message-ID: <1999610.6DN9RK2Tt3@aspire.rjw.lan> References: <20181123141831.8214-1-miquel.raynal@bootlin.com> <20181203102708.GA6090@e107981-ln.cambridge.arm.com> <20181203163846.494904f9@xps13> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <20181203163846.494904f9@xps13> Sender: linux-kernel-owner@vger.kernel.org To: Miquel Raynal Cc: Lorenzo Pieralisi , sudeep.holla@arm.com, 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 Monday, December 3, 2018 4:38:46 PM CET Miquel Raynal wrote: > Hi Lorenzo, > > Lorenzo Pieralisi wrote on Mon, 3 Dec 2018 > 10:27:08 +0000: > > > [+Rafael, Sudeep] > > > > On Fri, Nov 23, 2018 at 03:18:24PM +0100, Miquel Raynal wrote: > > > Add suspend and resume callbacks. The priority of these are > > > "_noirq()", to workaround early access to the registers done by the > > > PCI core through the ->read()/->write() callbacks at resume time. > > > > > > Signed-off-by: Miquel Raynal > > > --- > > > drivers/pci/controller/pci-aardvark.c | 52 +++++++++++++++++++++++++++ > > > 1 file changed, 52 insertions(+) > > > > > > diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c > > > index 108b3f15c410..7ecf1ac4036b 100644 > > > --- a/drivers/pci/controller/pci-aardvark.c > > > +++ b/drivers/pci/controller/pci-aardvark.c > > > @@ -1108,6 +1108,55 @@ static int advk_pcie_setup_clk(struct advk_pcie *pcie) > > > return ret; > > > } > > > > > > +static int __maybe_unused advk_pcie_suspend(struct device *dev) > > > +{ > > > + struct advk_pcie *pcie = dev_get_drvdata(dev); > > > + > > > + advk_pcie_disable_phy(pcie); > > > + > > > + clk_disable_unprepare(pcie->clk); > > > > I have noticed it is common practice, still, I would like to check whether > > it is allowed to call functions that may sleep in a NOIRQ suspend/resume > > callback ? > > You are right this is weird. I double checked and for instance, > pcie-mediatek.c, pci-tegra.c and pci-imx6.c do the exact same thing. There are > probably other cases where drivers call functions that may sleep from a NOIRQ > context. I am interested to know if this is valid and if not, what is the > alternative? > Yes, it is valid. _noirq means that the high-level action handlers will not be invoked for interrupts occurring during that period, but that doesn't apply to timer interrupts. IOW, don't expect *your* IRQ handler to be invoked then (if this is not a timer IRQ), but you can sleep. Thanks, Rafael