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Date:   Sat, 18 Jun 2022 11:39:27 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     ira.weiny@intel.com
Cc:     Dan Williams <dan.j.williams@intel.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Alison Schofield <alison.schofield@intel.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Ben Widawsky <bwidawsk@kernel.org>,
        linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org,
        linux-pci@vger.kernel.org
Subject: Re: [PATCH V11 3/8] PCI: Create PCI library functions in support of
 DOE mailboxes.
Message-ID: <20220618163927.GA1235355@bhelgaas>
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On Fri, Jun 17, 2022 at 05:40:19PM -0500, Bjorn Helgaas wrote:
> On Fri, Jun 10, 2022 at 01:22:54PM -0700, ira.weiny@intel.com wrote:
> > From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > 
> > Introduced in a PCI r6.0, sec 6.30, DOE provides a config space based
> > mailbox with standard protocol discovery.  Each mailbox is accessed
> > through a DOE Extended Capability.

> > + * pci_doe_get_irq_num() - Return the irq number for the mailbox at offset
> > + *
> > + * @pdev: The PCI device
> > + * @offset: Offset of the DOE mailbox
> > + *
> > + * Returns: irq number on success
> > + *	    -errno if irqs are not supported on this mailbox
> > + */
> > +int pci_doe_get_irq_num(struct pci_dev *pdev, int offset)
> > +{
> > +	u32 val;
> > +
> > +	pci_read_config_dword(pdev, offset + PCI_DOE_CAP, &val);
> > +	if (!FIELD_GET(PCI_DOE_CAP_INT, val))
> > +		return -EOPNOTSUPP;
> > +
> > +	return FIELD_GET(PCI_DOE_CAP_IRQ, val);
> > +}
> > +EXPORT_SYMBOL_GPL(pci_doe_get_irq_num);
> 
> Confusing function name (and comment) since PCI_DOE_CAP_IRQ is an
> Interrupt Message Number that has nothing to do with Linux IRQ
> numbers.
> 
> I see we already have PCI_EXP_FLAGS_IRQ, PCI_ERR_ROOT_AER_IRQ,
> PCI_EXP_DPC_IRQ, so I guess you're in good company.

Should have been more clear about this: I think we should rename the
new one to be PCI_DOE_CAP_INT_MSG_NUM or similar, and rename the
function as well.  It's too confusing to use "irq" for both Linux IRQs
and what the spec calls "Interupt Message Numbers".

Bjorn