Re: [PATCH 05/12] PCI: aardvark: add suspend to RAM support

Miquel Raynal
2018-12-03T15:38:51Z

Hi Lorenzo,

Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> 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 <miquel.raynal@bootlin.com>
> > ---
> > 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?

Thanks,
Miquèl