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authorAlex Williamson <alex.williamson@redhat.com>2015-01-15 18:16:04 -0600
committerBjorn Helgaas <bhelgaas@google.com>2015-01-16 10:04:38 -0600
commitf331a859e0ee5a898c1f47596eddad4c4f02d657 (patch)
treeb96653706bcaa5b2a779c8df2280894395345aa8
parent97bf6af1f928216fd6c5a66e8a57bfa95a659672 (diff)
PCI: Add flag for devices where we can't use bus reset
Enable a mechanism for devices to quirk that they do not behave when doing a PCI bus reset. We require a modest level of spec compliant behavior in order to do a reset, for instance the device should come out of reset without throwing errors and PCI config space should be accessible after reset. This is too much to ask for some devices. Link: http://lkml.kernel.org/r/20140923210318.498dacbd@dualc.maya.org Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.14+
-rw-r--r--drivers/pci/pci.c40
-rw-r--r--include/linux/pci.h2
2 files changed, 38 insertions, 4 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index cab05f31223f..e9d4fd861ba1 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3271,7 +3271,8 @@ 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)
+ if (pci_is_root_bus(dev->bus) || dev->subordinate ||
+ !dev->bus->self || dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
return -ENOTTY;
list_for_each_entry(pdev, &dev->bus->devices, bus_list)
@@ -3305,7 +3306,8 @@ static int pci_dev_reset_slot_function(struct pci_dev *dev, int probe)
{
struct pci_dev *pdev;
- if (dev->subordinate || !dev->slot)
+ if (dev->subordinate || !dev->slot ||
+ dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
return -ENOTTY;
list_for_each_entry(pdev, &dev->bus->devices, bus_list)
@@ -3557,6 +3559,20 @@ int pci_try_reset_function(struct pci_dev *dev)
}
EXPORT_SYMBOL_GPL(pci_try_reset_function);
+/* Do any devices on or below this bus prevent a bus reset? */
+static bool pci_bus_resetable(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
+ (dev->subordinate && !pci_bus_resetable(dev->subordinate)))
+ return false;
+ }
+
+ return true;
+}
+
/* Lock devices from the top of the tree down */
static void pci_bus_lock(struct pci_bus *bus)
{
@@ -3607,6 +3623,22 @@ unlock:
return 0;
}
+/* Do any devices on or below this slot prevent a bus reset? */
+static bool pci_slot_resetable(struct pci_slot *slot)
+{
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &slot->bus->devices, bus_list) {
+ if (!dev->slot || dev->slot != slot)
+ continue;
+ if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
+ (dev->subordinate && !pci_bus_resetable(dev->subordinate)))
+ return false;
+ }
+
+ return true;
+}
+
/* Lock devices from the top of the tree down */
static void pci_slot_lock(struct pci_slot *slot)
{
@@ -3728,7 +3760,7 @@ static int pci_slot_reset(struct pci_slot *slot, int probe)
{
int rc;
- if (!slot)
+ if (!slot || !pci_slot_resetable(slot))
return -ENOTTY;
if (!probe)
@@ -3820,7 +3852,7 @@ EXPORT_SYMBOL_GPL(pci_try_reset_slot);
static int pci_bus_reset(struct pci_bus *bus, int probe)
{
- if (!bus->self)
+ if (!bus->self || !pci_bus_resetable(bus))
return -ENOTTY;
if (probe)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 360a966a97a5..44627f1df4ca 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -175,6 +175,8 @@ enum pci_dev_flags {
PCI_DEV_FLAGS_DMA_ALIAS_DEVFN = (__force pci_dev_flags_t) (1 << 4),
/* Use a PCIe-to-PCI bridge alias even if !pci_is_pcie */
PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS = (__force pci_dev_flags_t) (1 << 5),
+ /* Do not use bus resets for device */
+ PCI_DEV_FLAGS_NO_BUS_RESET = (__force pci_dev_flags_t) (1 << 6),
};
enum pci_irq_reroute_variant {

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