linux-kernel - Re: [PATCH v13 09/10] PCI: kirin: fix poweroff sequence

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Date:   Tue, 19 Oct 2021 10:40:48 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Krzysztof Wilczyński <kw@...ux.com>,
        Songxiaowei <songxiaowei@...ilicon.com>,
        Binghui Wang <wangbinghui@...ilicon.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Rob Herring <robh@...nel.org>, linux-kernel@...r.kernel.org,
        linux-pci@...r.kernel.org
Subject: Re: [PATCH v13 09/10] PCI: kirin: fix poweroff sequence

On Mon, Oct 18, 2021 at 03:37:16PM +0100, Mauro Carvalho Chehab wrote:
> Em Mon, 18 Oct 2021 11:21:27 +0100
> Lorenzo Pieralisi <lorenzo.pieralisi@....com> escreveu:
> 
> > On Mon, Oct 18, 2021 at 08:07:34AM +0100, Mauro Carvalho Chehab wrote:
> > > This driver currently doesn't call dw_pcie_host_deinit()
> > > at the .remove() callback. This can cause an OOPS if the driver
> > > is unbound.  
> > 
> > This looks like a fix, it has to be marked as such.
> 
> Well, without patch 10/10, the .remove() ops won't be called,
> so, it is not really a fix, but I can surely add a c/c
> stable@...r.kernel.org and add a Fixes: tag here.

You have a point - unless we send patch 10 to stable as well I
would not tag it then.

> > > While here, add a poweroff function, in order to abstract
> > > between the internal and external PHY logic.
> > > 
> > > Acked-by: Xiaowei Song <songxiaowei@...ilicon.com>
> > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> > > ---
> > > 
> > > See [PATCH v13 00/10] at: https://lore.kernel.org/all/cover.1634539769.git.mchehab+huawei@kernel.org/
> > > 
> > >  drivers/pci/controller/dwc/pcie-kirin.c | 30 ++++++++++++++++---------
> > >  1 file changed, 20 insertions(+), 10 deletions(-)
> > > 
> > > diff --git a/drivers/pci/controller/dwc/pcie-kirin.c b/drivers/pci/controller/dwc/pcie-kirin.c
> > > index b17a194cf78d..ffc63d12f8ed 100644
> > > --- a/drivers/pci/controller/dwc/pcie-kirin.c
> > > +++ b/drivers/pci/controller/dwc/pcie-kirin.c
> > > @@ -680,6 +680,23 @@ static const struct dw_pcie_host_ops kirin_pcie_host_ops = {
> > >  	.host_init = kirin_pcie_host_init,
> > >  };
> > >  
> > > +static int kirin_pcie_power_off(struct kirin_pcie *kirin_pcie)
> > > +{
> > > +	int i;
> > > +
> > > +	if (kirin_pcie->type == PCIE_KIRIN_INTERNAL_PHY)
> > > +		return hi3660_pcie_phy_power_off(kirin_pcie);
> > > +
> > > +	for (i = 0; i < kirin_pcie->n_gpio_clkreq; i++) {
> > > +		gpio_direction_output(kirin_pcie->gpio_id_clkreq[i], 1);
> > > +	}  
> > 
> > It looks like you are adding functionality here (ie gpio), not
> > just wrapping common code in a function.
> 
> It is just reverting the power on logic there.

What I am saying is that executing:

for (i = 0; i < kirin_pcie->n_gpio_clkreq; i++)
	gpio_direction_output(kirin_pcie->gpio_id_clkreq[i], 1);

is an addition to what current code does AFAICS (ie you are not just
moving code into a function - kirin_pcie_power_off(), you are adding
to it), it is a logical change that belongs in a separate patch.

There are two logical changes:

- Adding dw_pcie_host_deinit()
- Moving PHY power off code into kirin_pcie_power_off() (and adding
  gpio handling in it)

That's what I read from the diffstat, please correct me if I am wrong.

Thanks,
Lorenzo

> > 
> > Also, remove the braces, they aren't needed.
> 
> Yeah, I forgot to drop it, when I dropped a tem code that had some
> dev_dbg() on it.
> 
> I'll drop on v14.
> 
> Regards,
> Mauro