From 64e8674fbe6bc848333a9b7e19f8cc019dde9eab Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Thu, 8 Aug 2013 14:09:24 -0600 Subject: PCI: Add pci_reset_bridge_secondary_bus() 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 and elsewhere. Signed-off-by: Alex Williamson Signed-off-by: Bjorn Helgaas --- include/linux/pci.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/pci.h b/include/linux/pci.h index 0fd1f1582fa1..35c1bc4909f3 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -924,6 +924,7 @@ 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); -- cgit v1.2.3-71-gd317 From 5c32b35b004f5ef70dcf62bbc42b8bed1e50b471 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Thu, 8 Aug 2013 14:09:31 -0600 Subject: PCI: Add hotplug_slot_ops.reset_slot() This optional callback allows hotplug controllers to perform slot specific resets. These may be necessary in cases where a normal secondary bus reset can interact with controller logic and expose spurious hotplugs. Signed-off-by: Alex Williamson Signed-off-by: Bjorn Helgaas --- include/linux/pci_hotplug.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pci_hotplug.h b/include/linux/pci_hotplug.h index 8db71dcd6337..bd32109e607e 100644 --- a/include/linux/pci_hotplug.h +++ b/include/linux/pci_hotplug.h @@ -63,6 +63,9 @@ enum pcie_link_width { * @get_adapter_status: Called to get see if an adapter is present in the slot or not. * If this field is NULL, the value passed in the struct hotplug_slot_info * will be used when this value is requested by a user. + * @reset_slot: Optional interface to allow override of a bus reset for the + * slot for cases where a secondary bus reset can result in spurious + * hotplug events or where a slot can be reset independent of the bus. * * The table of function pointers that is passed to the hotplug pci core by a * hotplug pci driver. These functions are called by the hotplug pci core when @@ -80,6 +83,7 @@ struct hotplug_slot_ops { int (*get_attention_status) (struct hotplug_slot *slot, u8 *value); int (*get_latch_status) (struct hotplug_slot *slot, u8 *value); int (*get_adapter_status) (struct hotplug_slot *slot, u8 *value); + int (*reset_slot) (struct hotplug_slot *slot, int probe); }; /** -- cgit v1.2.3-71-gd317 From 090a3c5322e900f468b3205b76d0837003ad57b2 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Thu, 8 Aug 2013 14:09:55 -0600 Subject: PCI: Add pci_reset_slot() and pci_reset_bus() Sometimes pci_reset_function() is not sufficient. We have cases where devices do not support any kind of reset, but there might be multiple functions on the bus preventing pci_reset_function() from doing a secondary bus reset. We also have cases where a device will advertise that it supports a PM reset, but really does nothing on D3hot->D0 (graphics cards are notorious for this). These devices often also have more than one function, so even blacklisting PM reset for them wouldn't allow a secondary bus reset through pci_reset_function(). If a driver supports multiple devices it should have the ability to induce a bus reset when it needs to. This patch provides that ability through pci_reset_slot() and pci_reset_bus(). It's the caller's responsibility when using these interfaces to understand that all of the devices in or below the slot (or on or below the bus) will be reset and therefore should be under control of the caller. PCI state of all the affected devices is saved and restored around these resets, but internal state of all of the affected devices is reset (which should be the intention). Signed-off-by: Alex Williamson Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 209 ++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/pci.h | 2 + 2 files changed, 211 insertions(+) (limited to 'include/linux') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index d48d9febc241..12fccc24925c 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3460,6 +3460,215 @@ int pci_reset_function(struct pci_dev *dev) } EXPORT_SYMBOL_GPL(pci_reset_function); +/* Lock devices from the top of the tree down */ +static void pci_bus_lock(struct pci_bus *bus) +{ + struct pci_dev *dev; + + list_for_each_entry(dev, &bus->devices, bus_list) { + pci_dev_lock(dev); + if (dev->subordinate) + pci_bus_lock(dev->subordinate); + } +} + +/* Unlock devices from the bottom of the tree up */ +static void pci_bus_unlock(struct pci_bus *bus) +{ + struct pci_dev *dev; + + list_for_each_entry(dev, &bus->devices, bus_list) { + if (dev->subordinate) + pci_bus_unlock(dev->subordinate); + pci_dev_unlock(dev); + } +} + +/* Lock devices from the top of the tree down */ +static void pci_slot_lock(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; + pci_dev_lock(dev); + if (dev->subordinate) + pci_bus_lock(dev->subordinate); + } +} + +/* Unlock devices from the bottom of the tree up */ +static void pci_slot_unlock(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->subordinate) + pci_bus_unlock(dev->subordinate); + pci_dev_unlock(dev); + } +} + +/* Save and disable devices from the top of the tree down */ +static void pci_bus_save_and_disable(struct pci_bus *bus) +{ + struct pci_dev *dev; + + list_for_each_entry(dev, &bus->devices, bus_list) { + pci_dev_save_and_disable(dev); + if (dev->subordinate) + pci_bus_save_and_disable(dev->subordinate); + } +} + +/* + * Restore devices from top of the tree down - parent bridges need to be + * restored before we can get to subordinate devices. + */ +static void pci_bus_restore(struct pci_bus *bus) +{ + struct pci_dev *dev; + + list_for_each_entry(dev, &bus->devices, bus_list) { + pci_dev_restore(dev); + if (dev->subordinate) + pci_bus_restore(dev->subordinate); + } +} + +/* Save and disable devices from the top of the tree down */ +static void pci_slot_save_and_disable(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; + pci_dev_save_and_disable(dev); + if (dev->subordinate) + pci_bus_save_and_disable(dev->subordinate); + } +} + +/* + * Restore devices from top of the tree down - parent bridges need to be + * restored before we can get to subordinate devices. + */ +static void pci_slot_restore(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; + pci_dev_restore(dev); + if (dev->subordinate) + pci_bus_restore(dev->subordinate); + } +} + +static int pci_slot_reset(struct pci_slot *slot, int probe) +{ + int rc; + + if (!slot) + return -ENOTTY; + + if (!probe) + pci_slot_lock(slot); + + might_sleep(); + + rc = pci_reset_hotplug_slot(slot->hotplug, probe); + + if (!probe) + pci_slot_unlock(slot); + + return rc; +} + +/** + * pci_reset_slot - reset a PCI slot + * @slot: PCI slot to reset + * + * A PCI bus may host multiple slots, each slot may support a reset mechanism + * independent of other slots. For instance, some slots may support slot power + * control. In the case of a 1:1 bus to slot architecture, this function may + * wrap the bus reset to avoid spurious slot related events such as hotplug. + * Generally a slot reset should be attempted before a bus reset. All of the + * function of the slot and any subordinate buses behind the slot are reset + * through this function. PCI config space of all devices in the slot and + * behind the slot is saved before and restored after reset. + * + * Return 0 on success, non-zero on error. + */ +int pci_reset_slot(struct pci_slot *slot) +{ + int rc; + + rc = pci_slot_reset(slot, 1); + if (rc) + return rc; + + pci_slot_save_and_disable(slot); + + rc = pci_slot_reset(slot, 0); + + pci_slot_restore(slot); + + return rc; +} +EXPORT_SYMBOL_GPL(pci_reset_slot); + +static int pci_bus_reset(struct pci_bus *bus, int probe) +{ + if (!bus->self) + return -ENOTTY; + + if (probe) + return 0; + + pci_bus_lock(bus); + + might_sleep(); + + pci_reset_bridge_secondary_bus(bus->self); + + pci_bus_unlock(bus); + + return 0; +} + +/** + * pci_reset_bus - reset a PCI bus + * @bus: top level PCI bus to reset + * + * Do a bus reset on the given bus and any subordinate buses, saving + * and restoring state of all devices. + * + * Return 0 on success, non-zero on error. + */ +int pci_reset_bus(struct pci_bus *bus) +{ + int rc; + + rc = pci_bus_reset(bus, 1); + if (rc) + return rc; + + pci_bus_save_and_disable(bus); + + rc = pci_bus_reset(bus, 0); + + pci_bus_restore(bus); + + return rc; +} +EXPORT_SYMBOL_GPL(pci_reset_bus); + /** * pcix_get_max_mmrbc - get PCI-X maximum designed memory read byte count * @dev: PCI device to query diff --git a/include/linux/pci.h b/include/linux/pci.h index 35c1bc4909f3..1a8fd3464daf 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -924,6 +924,8 @@ 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); +int pci_reset_slot(struct pci_slot *slot); +int pci_reset_bus(struct pci_bus *bus); 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); -- cgit v1.2.3-71-gd317 From 9a3d2b9beefd5b07c1d8f70ded01b88f203ee304 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Wed, 14 Aug 2013 14:06:05 -0600 Subject: PCI: Add pci_probe_reset_slot() and pci_probe_reset_bus() Users of pci_reset_bus() and pci_reset_slot() need a way to probe whether the bus or slot supports reset. Add trivial helper functions and export them as vfio-pci will make use of these. Signed-off-by: Alex Williamson Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 24 ++++++++++++++++++++++++ include/linux/pci.h | 2 ++ 2 files changed, 26 insertions(+) (limited to 'include/linux') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index ea5e70486174..7f89372483dd 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3609,6 +3609,18 @@ static int pci_slot_reset(struct pci_slot *slot, int probe) return rc; } +/** + * pci_probe_reset_slot - probe whether a PCI slot can be reset + * @slot: PCI slot to probe + * + * Return 0 if slot can be reset, negative if a slot reset is not supported. + */ +int pci_probe_reset_slot(struct pci_slot *slot) +{ + return pci_slot_reset(slot, 1); +} +EXPORT_SYMBOL_GPL(pci_probe_reset_slot); + /** * pci_reset_slot - reset a PCI slot * @slot: PCI slot to reset @@ -3661,6 +3673,18 @@ static int pci_bus_reset(struct pci_bus *bus, int probe) return 0; } +/** + * pci_probe_reset_bus - probe whether a PCI bus can be reset + * @bus: PCI bus to probe + * + * Return 0 if bus can be reset, negative if a bus reset is not supported. + */ +int pci_probe_reset_bus(struct pci_bus *bus) +{ + return pci_bus_reset(bus, 1); +} +EXPORT_SYMBOL_GPL(pci_probe_reset_bus); + /** * pci_reset_bus - reset a PCI bus * @bus: top level PCI bus to reset diff --git a/include/linux/pci.h b/include/linux/pci.h index 1a8fd3464daf..daf40cd851df 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -924,7 +924,9 @@ 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); +int pci_probe_reset_slot(struct pci_slot *slot); int pci_reset_slot(struct pci_slot *slot); +int pci_probe_reset_bus(struct pci_bus *bus); int pci_reset_bus(struct pci_bus *bus); void pci_reset_bridge_secondary_bus(struct pci_dev *dev); void pci_update_resource(struct pci_dev *dev, int resno); -- cgit v1.2.3-71-gd317