linux-kernel - Re: [PATCH v3 06/13] PCI: qcom-ep: Modify 'global_irq' and 'perst

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Message-ID: <20240802074319.GA57846@thinkpad>
Date: Fri, 2 Aug 2024 13:13:19 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Bjorn Helgaas <helgaas@...nel.org>
Cc: Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczyński <kw@...ux.com>,
	Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Kishon Vijay Abraham I <kishon@...nel.org>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konradybcio@...nel.org>, linux-pci@...r.kernel.org,
	linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org,
	Konrad Dybcio <konrad.dybcio@...aro.org>
Subject: Re: [PATCH v3 06/13] PCI: qcom-ep: Modify 'global_irq' and
 'perst_irq' IRQ device names

On Thu, Aug 01, 2024 at 12:23:08PM -0500, Bjorn Helgaas wrote:
> On Wed, Jul 31, 2024 at 04:20:09PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> > From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> > 
> > Currently, the IRQ device name for both of these IRQs doesn't have Qcom
> > specific prefix and PCIe domain number. This causes 2 issues:
> > 
> > 1. Pollutes the global IRQ namespace since 'global' is a common name.
> > 2. When more than one EP controller instance is present in the SoC, naming
> > conflict will occur.
> > 
> > Hence, add 'qcom_pcie_ep_' prefix and PCIe domain number suffix to the IRQ
> > names to uniquely identify the IRQs and also to fix the above mentioned
> > issues.
> > 
> > Reviewed-by: Konrad Dybcio <konrad.dybcio@...aro.org>
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> > ---
> >  drivers/pci/controller/dwc/pcie-qcom-ep.c | 16 ++++++++++++++--
> >  1 file changed, 14 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> > index 0bb0a056dd8f..d0a27fa6fdc8 100644
> > --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
> > +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> > @@ -711,8 +711,15 @@ static irqreturn_t qcom_pcie_ep_perst_irq_thread(int irq, void *data)
> >  static int qcom_pcie_ep_enable_irq_resources(struct platform_device *pdev,
> >  					     struct qcom_pcie_ep *pcie_ep)
> >  {
> > +	struct device *dev = pcie_ep->pci.dev;
> > +	char *name;
> >  	int ret;
> >  
> > +	name = devm_kasprintf(dev, GFP_KERNEL, "qcom_pcie_ep_global_irq%d",
> > +			      pcie_ep->pci.ep.epc->domain_nr);
> > +	if (!name)
> > +		return -ENOMEM;
> 
> I assume this is what shows up in /proc/interrupts?

Yes.

> I always wonder
> why it doesn't include dev_name().  A few drivers do that, but
> apparently it's not universally desirable.  It's sort of annoying
> that, e.g., we get a bunch of "aerdrv" interrupts with no clue which
> device they relate to.
> 

dev_name() can be big at times. I wouldn't recommend to include it unless there
are no other ways to differentiate between IRQs. Luckily PCIe has the domain
number that we can use to differentiate these IRQs.

- Mani

> >  	pcie_ep->global_irq = platform_get_irq_byname(pdev, "global");
> >  	if (pcie_ep->global_irq < 0)
> >  		return pcie_ep->global_irq;
> > @@ -720,18 +727,23 @@ static int qcom_pcie_ep_enable_irq_resources(struct platform_device *pdev,
> >  	ret = devm_request_threaded_irq(&pdev->dev, pcie_ep->global_irq, NULL,
> >  					qcom_pcie_ep_global_irq_thread,
> >  					IRQF_ONESHOT,
> > -					"global_irq", pcie_ep);
> > +					name, pcie_ep);
> >  	if (ret) {
> >  		dev_err(&pdev->dev, "Failed to request Global IRQ\n");
> >  		return ret;
> >  	}
> >  
> > +	name = devm_kasprintf(dev, GFP_KERNEL, "qcom_pcie_ep_perst_irq%d",
> > +			      pcie_ep->pci.ep.epc->domain_nr);
> > +	if (!name)
> > +		return -ENOMEM;
> > +
> >  	pcie_ep->perst_irq = gpiod_to_irq(pcie_ep->reset);
> >  	irq_set_status_flags(pcie_ep->perst_irq, IRQ_NOAUTOEN);
> >  	ret = devm_request_threaded_irq(&pdev->dev, pcie_ep->perst_irq, NULL,
> >  					qcom_pcie_ep_perst_irq_thread,
> >  					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
> > -					"perst_irq", pcie_ep);
> > +					name, pcie_ep);
> >  	if (ret) {
> >  		dev_err(&pdev->dev, "Failed to request PERST IRQ\n");
> >  		disable_irq(pcie_ep->global_irq);
> > 
> > -- 
> > 2.25.1
> > 
> > 

-- 
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