[PATCH v3 4/9] pci: Add slot reset option to pci_dev_reset

Alex Williamson
2013-08-01T16:55:41Z

If the hotplug controller provides a way to reset a slot, use that
before a direct parent bus reset. Like the bus reset option, this is
only available when a single pci_dev occupies the slot.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
drivers/pci/pci.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index bfd629c..db90692 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -22,6 +22,7 @@
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/pm_runtime.h>
+#include <linux/pci_hotplug.h>
#include <asm-generic/pci-bridge.h>
#include <asm/setup.h>
#include "pci.h"
@@ -3317,6 +3318,35 @@ static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
return 0;
}

+static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, int probe)
+{
+ int rc = -ENOTTY;
+
+ if (!hotplug || !try_module_get(hotplug->ops->owner))
+ return rc;
+
+ if (hotplug->ops->reset_slot)
+ rc = hotplug->ops->reset_slot(hotplug, probe);
+
+ module_put(hotplug->ops->owner);
+
+ return rc;
+}
+
+static int pci_dev_reset_slot_function(struct pci_dev *dev, int probe)
+{
+ struct pci_dev *pdev;
+
+ if (dev->subordinate || !dev->slot)
+ return -ENOTTY;
+
+ list_for_each_entry(pdev, &dev->bus->devices, bus_list)
+ if (pdev != dev && pdev->slot == dev->slot)
+ return -ENOTTY;
+
+ return pci_reset_hotplug_slot(dev->slot->hotplug, probe);
+}
+
static int __pci_dev_reset(struct pci_dev *dev, int probe)
{
int rc;
@@ -3339,6 +3369,10 @@ static int __pci_dev_reset(struct pci_dev *dev, int probe)
if (rc != -ENOTTY)
goto done;

+ rc = pci_dev_reset_slot_function(dev, probe);
+ if (rc != -ENOTTY)
+ goto done;
+
rc = pci_parent_bus_reset(dev, probe);
done:
return rc;