Patchwork [v2,02/27] of/pci: Add of_pci_get_devfn() function

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Submitter Thomas Petazzoni
Date Jan. 28, 2013, 6:56 p.m.
Message ID <1359399397-29729-3-git-send-email-thomas.petazzoni@free-electrons.com>
Download mbox | patch
Permalink /patch/216304/
State Not Applicable
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Comments

Thomas Petazzoni - Jan. 28, 2013, 6:56 p.m.
From: Thierry Reding <thierry.reding@avionic-design.de>

This function can be used to parse the device and function number from a
standard 5-cell PCI resource. PCI_SLOT() and PCI_FUNC() can be used on
the returned value obtain the device and function numbers respectively.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 drivers/of/of_pci.c    |   32 ++++++++++++++++++++++++++++----
 include/linux/of_pci.h |    1 +
 2 files changed, 29 insertions(+), 4 deletions(-)
Stephen Warren - Jan. 28, 2013, 10 p.m.
On 01/28/2013 11:56 AM, Thomas Petazzoni wrote:
> From: Thierry Reding <thierry.reding@avionic-design.de>
> 
> This function can be used to parse the device and function number from a
> standard 5-cell PCI resource. PCI_SLOT() and PCI_FUNC() can be used on
> the returned value obtain the device and function numbers respectively.

> diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c

>  static inline int __of_pci_pci_compare(struct device_node *node,
>  				       unsigned int devfn)
>  {
> -	unsigned int size;
> -	const __be32 *reg = of_get_property(node, "reg", &size);
> +	int err;

I think I commented when Thierry posted this, that calling that "err"
seems a little odd. Thierry replied:

Maybe renaming the devfn parameter to data and using devfn for the local
variable would be more obvious.
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Thierry Reding - Jan. 28, 2013, 10:16 p.m.
On Mon, Jan 28, 2013 at 03:00:10PM -0700, Stephen Warren wrote:
> On 01/28/2013 11:56 AM, Thomas Petazzoni wrote:
> > From: Thierry Reding <thierry.reding@avionic-design.de>
> > 
> > This function can be used to parse the device and function number from a
> > standard 5-cell PCI resource. PCI_SLOT() and PCI_FUNC() can be used on
> > the returned value obtain the device and function numbers respectively.
> 
> > diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
> 
> >  static inline int __of_pci_pci_compare(struct device_node *node,
> >  				       unsigned int devfn)
> >  {
> > -	unsigned int size;
> > -	const __be32 *reg = of_get_property(node, "reg", &size);
> > +	int err;
> 
> I think I commented when Thierry posted this, that calling that "err"
> seems a little odd. Thierry replied:
> 
> Maybe renaming the devfn parameter to data and using devfn for the local
> variable would be more obvious.

That's already fixed up in my series. I was going to wait until I was
done with the MSI rework but maybe posting an intermediate version is in
order to share the latest state.

Thierry
Thomas Petazzoni - Jan. 29, 2013, 10:04 a.m.
Thierry, Stephen,

On Mon, 28 Jan 2013 23:16:04 +0100, Thierry Reding wrote:

> That's already fixed up in my series. I was going to wait until I was
> done with the MSI rework but maybe posting an intermediate version is in
> order to share the latest state.

Thanks! Those first four patches are definitely shared between our
series.

Thomas

Patch

diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 13e37e2..0dd52df 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -7,12 +7,13 @@ 
 static inline int __of_pci_pci_compare(struct device_node *node,
 				       unsigned int devfn)
 {
-	unsigned int size;
-	const __be32 *reg = of_get_property(node, "reg", &size);
+	int err;
 
-	if (!reg || size < 5 * sizeof(__be32))
+	err = of_pci_get_devfn(node);
+	if (err < 0)
 		return 0;
-	return ((be32_to_cpup(&reg[0]) >> 8) & 0xff) == devfn;
+
+	return devfn == err;
 }
 
 struct device_node *of_pci_find_child_device(struct device_node *parent,
@@ -40,3 +41,26 @@  struct device_node *of_pci_find_child_device(struct device_node *parent,
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(of_pci_find_child_device);
+
+/**
+ * of_pci_get_devfn() - Get device and function numbers for a device node
+ * @np: device node
+ *
+ * Parses a standard 5-cell PCI resource and returns an 8-bit value that can
+ * be passed to the PCI_SLOT() and PCI_FUNC() macros to extract the device
+ * and function numbers respectively. On error a negative error code is
+ * returned.
+ */
+int of_pci_get_devfn(struct device_node *np)
+{
+	unsigned int size;
+	const __be32 *reg;
+
+	reg = of_get_property(np, "reg", &size);
+
+	if (!reg || size < 5 * sizeof(__be32))
+		return -EINVAL;
+
+	return (be32_to_cpup(reg) >> 8) & 0xff;
+}
+EXPORT_SYMBOL_GPL(of_pci_get_devfn);
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index bb115de..91ec484 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -10,5 +10,6 @@  int of_irq_map_pci(const struct pci_dev *pdev, struct of_irq *out_irq);
 struct device_node;
 struct device_node *of_pci_find_child_device(struct device_node *parent,
 					     unsigned int devfn);
+int of_pci_get_devfn(struct device_node *np);
 
 #endif