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From: Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
To: <linux-pci@vger.kernel.org>, <linuxppc-dev@lists.ozlabs.org>
Cc: Bjorn Helgaas <helgaas@kernel.org>, <linux@yadro.com>,
	Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
Subject: [PATCH RFC v4 06/21] PCI: Pause the devices with movable BARs during rescan
Date: Mon, 11 Mar 2019 16:31:07 +0300
Message-ID: <20190311133122.11417-7-s.miroshnichenko@yadro.com> (raw)
In-Reply-To: <20190311133122.11417-1-s.miroshnichenko@yadro.com>

Drivers indicate their support of movable BARs by implementing the
new rescan_prepare() and rescan_done() hooks in the struct pci_driver.

All device's activity must be stopped during a rescan, and iounmap()
+ioremap() must be applied to every used BAR.

Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
---
 drivers/pci/probe.c | 51 +++++++++++++++++++++++++++++++++++++++++++--
 include/linux/pci.h |  2 ++
 2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 977a127ce791..88350dd56344 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -3248,6 +3248,38 @@ unsigned int pci_rescan_bus_bridge_resize(struct pci_dev *bridge)
 	return max;
 }
 
+static void pci_bus_rescan_prepare(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		struct pci_bus *child = dev->subordinate;
+
+		if (child) {
+			pci_bus_rescan_prepare(child);
+		} else if (dev->driver &&
+			   dev->driver->rescan_prepare) {
+			dev->driver->rescan_prepare(dev);
+		}
+	}
+}
+
+static void pci_bus_rescan_done(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		struct pci_bus *child = dev->subordinate;
+
+		if (child) {
+			pci_bus_rescan_done(child);
+		} else if (dev->driver &&
+			   dev->driver->rescan_done) {
+			dev->driver->rescan_done(dev);
+		}
+	}
+}
+
 /**
  * pci_rescan_bus - Scan a PCI bus for devices
  * @bus: PCI bus to scan
@@ -3261,8 +3293,23 @@ unsigned int pci_rescan_bus(struct pci_bus *bus)
 {
 	unsigned int max;
 
-	max = pci_scan_child_bus(bus);
-	pci_assign_unassigned_bus_resources(bus);
+	if (pci_movable_bars_enabled()) {
+		struct pci_bus *root = bus;
+
+		while (!pci_is_root_bus(root))
+			root = root->parent;
+
+		pci_bus_rescan_prepare(root);
+
+		max = pci_scan_child_bus(root);
+		pci_assign_unassigned_root_bus_resources(root);
+
+		pci_bus_rescan_done(root);
+	} else {
+		max = pci_scan_child_bus(bus);
+		pci_assign_unassigned_bus_resources(bus);
+	}
+
 	pci_bus_add_devices(bus);
 
 	return max;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index cbe661aff9f5..3d52f5538282 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -780,6 +780,8 @@ struct pci_driver {
 	int  (*resume)(struct pci_dev *dev);	/* Device woken up */
 	void (*shutdown)(struct pci_dev *dev);
 	int  (*sriov_configure)(struct pci_dev *dev, int num_vfs); /* On PF */
+	void (*rescan_prepare)(struct pci_dev *dev);
+	void (*rescan_done)(struct pci_dev *dev);
 	const struct pci_error_handlers *err_handler;
 	const struct attribute_group **groups;
 	struct device_driver	driver;
-- 
2.20.1


  parent reply index

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-11 13:31 [PATCH RFC v4 00/21] PCI: Allow BAR movement during hotplug Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 01/21] PCI: Fix writing invalid BARs during pci_restore_state() Sergey Miroshnichenko
2019-03-26 14:02   ` Bjorn Helgaas
2019-03-11 13:31 ` [PATCH RFC v4 02/21] PCI: Fix race condition in pci_enable/disable_device() Sergey Miroshnichenko
2019-03-26 19:00   ` Bjorn Helgaas
2019-03-27 17:11     ` Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 03/21] PCI: Enable bridge's I/O and MEM access for hotplugged devices Sergey Miroshnichenko
2019-03-26 19:13   ` Bjorn Helgaas
2019-03-27 17:13     ` Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 04/21] PCI: Define PCI-specific version of the release_child_resources() Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 05/21] PCI: hotplug: Add a flag for the movable BARs feature Sergey Miroshnichenko
2019-03-26 19:24   ` Bjorn Helgaas
2019-03-27 17:16     ` Sergey Miroshnichenko
2019-03-11 13:31 ` Sergey Miroshnichenko [this message]
2019-03-11 13:31 ` [PATCH RFC v4 07/21] PCI: Wake up bridges during rescan when movable BARs enabled Sergey Miroshnichenko
2019-03-26 19:28   ` Bjorn Helgaas
2019-03-11 13:31 ` [PATCH RFC v4 08/21] nvme-pci: Handle movable BARs Sergey Miroshnichenko
2019-03-26 20:20   ` Bjorn Helgaas
2019-03-27 17:30     ` Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 09/21] PCI: Mark immovable BARs with PCI_FIXED Sergey Miroshnichenko
2019-03-26 20:28   ` Bjorn Helgaas
2019-03-27 17:03     ` David Laight
2019-03-27 17:39       ` Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 10/21] PCI: Fix assigning of fixed prefetchable resources Sergey Miroshnichenko
2019-03-26 20:37   ` Bjorn Helgaas
2019-03-11 13:31 ` [PATCH RFC v4 11/21] PCI: Release and reassign the root bridge resources during rescan Sergey Miroshnichenko
2019-03-26 20:41   ` Bjorn Helgaas
2019-03-27 17:40     ` Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 12/21] PCI: Don't allow hotplugged devices to steal resources Sergey Miroshnichenko
2019-03-26 20:55   ` Bjorn Helgaas
2019-03-27 18:02     ` Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 13/21] PCI: Include fixed BARs into the bus size calculating Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 14/21] PCI: Don't reserve memory for hotplug when enabled movable BARs Sergey Miroshnichenko
2019-03-26 20:57   ` Bjorn Helgaas
2019-03-11 13:31 ` [PATCH RFC v4 15/21] PCI: Allow the failed resources to be reassigned later Sergey Miroshnichenko
2019-03-26 20:58   ` Bjorn Helgaas
2019-03-11 13:31 ` [PATCH RFC v4 16/21] PCI: Calculate fixed areas of bridge windows based on fixed BARs Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 17/21] PCI: Calculate boundaries for bridge windows Sergey Miroshnichenko
2019-03-26 21:01   ` Bjorn Helgaas
2019-03-11 13:31 ` [PATCH RFC v4 18/21] PCI: Make sure bridge windows include their fixed BARs Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 19/21] PCI: Prioritize fixed BAR assigning over the movable ones Sergey Miroshnichenko
2019-03-11 13:31 ` [PATCH RFC v4 20/21] PCI: pciehp: Add support for the movable BARs feature Sergey Miroshnichenko
2019-03-26 21:11   ` Bjorn Helgaas
2019-03-11 13:31 ` [PATCH RFC v4 21/21] powerpc/pci: Fix crash with enabled movable BARs Sergey Miroshnichenko

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