Patchwork [v2,1/8] pci: Create pci_reset_bridge_secondary_bus()

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Submitter Alex Williamson
Date May 8, 2013, 2:57 a.m.
Message ID <20130508025740.30771.50033.stgit@bling.home>
Download mbox | patch
Permalink /patch/242491/
State Superseded
Headers show

Comments

Alex Williamson - May 8, 2013, 2:57 a.m.
Move the secondary bus reset code from pci_parent_bus_reset() into its own
function.  Export it as we'll later be calling it from hotplug controllers.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 drivers/pci/pci.c   |   32 +++++++++++++++++++++++---------
 include/linux/pci.h |    1 +
 2 files changed, 24 insertions(+), 9 deletions(-)


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Don Dutile - May 8, 2013, 7:14 p.m.
On 05/07/2013 10:57 PM, Alex Williamson wrote:
> Move the secondary bus reset code from pci_parent_bus_reset() into its own
> function.  Export it as we'll later be calling it from hotplug controllers.
>
> Signed-off-by: Alex Williamson<alex.williamson@redhat.com>
> ---
>   drivers/pci/pci.c   |   32 +++++++++++++++++++++++---------
>   include/linux/pci.h |    1 +
>   2 files changed, 24 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index b099e00..d0f313f 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3210,9 +3210,30 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
>   	return 0;
>   }
>
> -static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
> +/**
> + * pci_reset_bridge_secondary_bus - Reset the secondary bus on a PCI bridge.
> + * @dev: Bridge device
> + *
> + * Use the bridge control register to assert reset on the secondary bus.
> + * Devices on the secondary bus are left in power-on state.
> + */
> +void pci_reset_bridge_secondary_bus(struct pci_dev *dev)
see recommended api change below...

>   {
>   	u16 ctrl;
> +
> +	pci_read_config_word(dev, PCI_BRIDGE_CONTROL,&ctrl);
> +	ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
> +	pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
> +	msleep(100);
> +
> +	ctrl&= ~PCI_BRIDGE_CTL_BUS_RESET;
> +	pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
> +	msleep(100);
> +}
> +EXPORT_SYMBOL_GPL(pci_reset_bridge_secondary_bus);
> +
> +static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
> +{
>   	struct pci_dev *pdev;
>
>   	if (pci_is_root_bus(dev->bus) || dev->subordinate || !dev->bus->self)
> @@ -3225,14 +3246,7 @@ static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
>   	if (probe)
>   		return 0;
>
> -	pci_read_config_word(dev->bus->self, PCI_BRIDGE_CONTROL,&ctrl);
> -	ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
> -	pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
> -	msleep(100);
> -
> -	ctrl&= ~PCI_BRIDGE_CTL_BUS_RESET;
> -	pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
> -	msleep(100);
> +	pci_reset_bridge_secondary_bus(dev->bus->self);
>
It makes more sense to pass the pci-bus struct of the bus you want to reset,
instead of the pdev of the bridge that bus is sourced by.
i.e, dev->bus,  and above, extract the pdev from the bus-struct.
That way, devices asking for bus-reset, don't have to know the bus-struct details
to make the call right... just their own pdev->bus reference.
(more object-like/clean).

>   	return 0;
>   }
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 710067f..695620c 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -905,6 +905,7 @@ int pcie_set_mps(struct pci_dev *dev, int mps);
>   int __pci_reset_function(struct pci_dev *dev);
>   int __pci_reset_function_locked(struct pci_dev *dev);
>   int pci_reset_function(struct pci_dev *dev);
> +void pci_reset_bridge_secondary_bus(struct pci_dev *dev);
and final tweak.

>   void pci_update_resource(struct pci_dev *dev, int resno);
>   int __must_check pci_assign_resource(struct pci_dev *dev, int i);
>   int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align);
>
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Alex Williamson - May 8, 2013, 7:30 p.m.
On Wed, 2013-05-08 at 15:14 -0400, Don Dutile wrote:
> On 05/07/2013 10:57 PM, Alex Williamson wrote:
> > Move the secondary bus reset code from pci_parent_bus_reset() into its own
> > function.  Export it as we'll later be calling it from hotplug controllers.
> >
> > Signed-off-by: Alex Williamson<alex.williamson@redhat.com>
> > ---
> >   drivers/pci/pci.c   |   32 +++++++++++++++++++++++---------
> >   include/linux/pci.h |    1 +
> >   2 files changed, 24 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index b099e00..d0f313f 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -3210,9 +3210,30 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
> >   	return 0;
> >   }
> >
> > -static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
> > +/**
> > + * pci_reset_bridge_secondary_bus - Reset the secondary bus on a PCI bridge.
> > + * @dev: Bridge device
> > + *
> > + * Use the bridge control register to assert reset on the secondary bus.
> > + * Devices on the secondary bus are left in power-on state.
> > + */
> > +void pci_reset_bridge_secondary_bus(struct pci_dev *dev)
> see recommended api change below...
> 
> >   {
> >   	u16 ctrl;
> > +
> > +	pci_read_config_word(dev, PCI_BRIDGE_CONTROL,&ctrl);
> > +	ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
> > +	pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
> > +	msleep(100);
> > +
> > +	ctrl&= ~PCI_BRIDGE_CTL_BUS_RESET;
> > +	pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
> > +	msleep(100);
> > +}
> > +EXPORT_SYMBOL_GPL(pci_reset_bridge_secondary_bus);
> > +
> > +static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
> > +{
> >   	struct pci_dev *pdev;
> >
> >   	if (pci_is_root_bus(dev->bus) || dev->subordinate || !dev->bus->self)
> > @@ -3225,14 +3246,7 @@ static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
> >   	if (probe)
> >   		return 0;
> >
> > -	pci_read_config_word(dev->bus->self, PCI_BRIDGE_CONTROL,&ctrl);
> > -	ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
> > -	pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
> > -	msleep(100);
> > -
> > -	ctrl&= ~PCI_BRIDGE_CTL_BUS_RESET;
> > -	pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
> > -	msleep(100);
> > +	pci_reset_bridge_secondary_bus(dev->bus->self);
> >
> It makes more sense to pass the pci-bus struct of the bus you want to reset,
> instead of the pdev of the bridge that bus is sourced by.
> i.e, dev->bus,  and above, extract the pdev from the bus-struct.
> That way, devices asking for bus-reset, don't have to know the bus-struct details
> to make the call right... just their own pdev->bus reference.
> (more object-like/clean).

Have you read patch 7/8 or does this comment take that patch into
account?  For the bus reset and slot reset interfaces the API I'm
proposing does require passing a pci_bus and pci_slot respectively.
Here we have a bridge (pci_dev) and we want to reset the secondary bus
on that bridge and I think the function name indicates that.  Thanks,

Alex

> >   	return 0;
> >   }
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index 710067f..695620c 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -905,6 +905,7 @@ int pcie_set_mps(struct pci_dev *dev, int mps);
> >   int __pci_reset_function(struct pci_dev *dev);
> >   int __pci_reset_function_locked(struct pci_dev *dev);
> >   int pci_reset_function(struct pci_dev *dev);
> > +void pci_reset_bridge_secondary_bus(struct pci_dev *dev);
> and final tweak.
> 
> >   void pci_update_resource(struct pci_dev *dev, int resno);
> >   int __must_check pci_assign_resource(struct pci_dev *dev, int i);
> >   int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align);
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 



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Patch

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b099e00..d0f313f 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3210,9 +3210,30 @@  static int pci_pm_reset(struct pci_dev *dev, int probe)
 	return 0;
 }
 
-static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
+/**
+ * pci_reset_bridge_secondary_bus - Reset the secondary bus on a PCI bridge.
+ * @dev: Bridge device
+ *
+ * Use the bridge control register to assert reset on the secondary bus.
+ * Devices on the secondary bus are left in power-on state.
+ */
+void pci_reset_bridge_secondary_bus(struct pci_dev *dev)
 {
 	u16 ctrl;
+
+	pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &ctrl);
+	ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
+	pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
+	msleep(100);
+
+	ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
+	pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);
+	msleep(100);
+}
+EXPORT_SYMBOL_GPL(pci_reset_bridge_secondary_bus);
+
+static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
+{
 	struct pci_dev *pdev;
 
 	if (pci_is_root_bus(dev->bus) || dev->subordinate || !dev->bus->self)
@@ -3225,14 +3246,7 @@  static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
 	if (probe)
 		return 0;
 
-	pci_read_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, &ctrl);
-	ctrl |= PCI_BRIDGE_CTL_BUS_RESET;
-	pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
-	msleep(100);
-
-	ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
-	pci_write_config_word(dev->bus->self, PCI_BRIDGE_CONTROL, ctrl);
-	msleep(100);
+	pci_reset_bridge_secondary_bus(dev->bus->self);
 
 	return 0;
 }
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 710067f..695620c 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -905,6 +905,7 @@  int pcie_set_mps(struct pci_dev *dev, int mps);
 int __pci_reset_function(struct pci_dev *dev);
 int __pci_reset_function_locked(struct pci_dev *dev);
 int pci_reset_function(struct pci_dev *dev);
+void pci_reset_bridge_secondary_bus(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);
 int __must_check pci_assign_resource(struct pci_dev *dev, int i);
 int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align);