Commit 0dad3ce5 authored Apr 08, 2021 by Raphael Norwitz Committed by Bjorn Helgaas May 24, 2021

PCI: Add pci_reset_bus_function() Secondary Bus Reset interface



pci_parent_bus_reset() resets a device by performing a Secondary Bus Reset
on a PCI-to-PCI bridge leading to the device.

pci_dev_reset_slot_function() does the same, except that it uses a hotplug
driver to keep the reset from looking like a hot-remove followed by a
hot-add.

Add a pci_reset_bus_function() wrapper, which attempts the hotplug driver
slot reset and falls back to the parent bus reset if that fails.  This
provides a single interface for performing a Secondary Bus Reset.

[bhelgaas: commit log, don't expose yet]
Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20210323100625.0021a943@omen.home.shazbot.org/
Link: https://lore.kernel.org/r/20210408182328.12323-1-raphael.norwitz@nutanix.com


Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>

parent 6efb943b

drivers/pci/pci.c

+12 −8

Original line number	Diff line number	Diff line
		@@ -5020,6 +5020,16 @@ static int pci_dev_reset_slot_function(struct pci_dev *dev, int probe)
		return pci_reset_hotplug_slot(dev->slot->hotplug, probe);
		}

		static int pci_reset_bus_function(struct pci_dev *dev, int probe)
		{
		int rc;

		rc = pci_dev_reset_slot_function(dev, probe);
		if (rc != -ENOTTY)
		return rc;
		return pci_parent_bus_reset(dev, probe);
		}

		static void pci_dev_lock(struct pci_dev *dev)
		{
		pci_cfg_access_lock(dev);
		@@ -5140,10 +5150,7 @@ int __pci_reset_function_locked(struct pci_dev *dev)
		rc = pci_pm_reset(dev, 0);
		if (rc != -ENOTTY)
		return rc;
		rc = pci_dev_reset_slot_function(dev, 0);
		if (rc != -ENOTTY)
		return rc;
		return pci_parent_bus_reset(dev, 0);
		return pci_reset_bus_function(dev, 0);
		}
		EXPORT_SYMBOL_GPL(__pci_reset_function_locked);

		@@ -5173,13 +5180,10 @@ int pci_probe_reset_function(struct pci_dev *dev)
		if (rc != -ENOTTY)
		return rc;
		rc = pci_pm_reset(dev, 1);
		if (rc != -ENOTTY)
		return rc;
		rc = pci_dev_reset_slot_function(dev, 1);
		if (rc != -ENOTTY)
		return rc;

		return pci_parent_bus_reset(dev, 1);
		return pci_reset_bus_function(dev, 1);
		}

		/**