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Commit 296ccb08 authored Apr 03, 2009 by Yuji Shimada Committed by Jesse Barnes Apr 06, 2009

PCI: Setup disabled bridges even if buses are added



This patch sets up disabled bridges even if buses have already been
added.

pci_assign_unassigned_resources is called after buses are added.
pci_assign_unassigned_resources calls pci_bus_assign_resources.
pci_bus_assign_resources calls pci_setup_bridge to configure BARs of
bridges.

Currently pci_setup_bridge returns immediately if the bus have already
been added. So pci_assign_unassigned_resources can't configure BARs of
bridges that were added in a disabled state; this patch fixes the issue.

On logical hot-add, we need to prevent the kernel from re-initializing
bridges that have already been initialized. To achieve this,
pci_setup_bridge returns immediately if the bridge have already been
enabled.

We don't need to check whether the specified bus is a root bus or not.
pci_setup_bridge is not called on a root bus, because a root bus does
not have a bridge.

The patch adds a new helper function, pci_is_enabled. I made the
function name similar to pci_is_managed. The codes which use
enable_cnt directly are changed to use pci_is_enabled.

Acked-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Yuji Shimada <shimada-yxb@necst.nec.co.jp>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

parent 7eb93b17

drivers/pci/bus.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -184,7 +184,7 @@ void pci_enable_bridges(struct pci_bus *bus)

		list_for_each_entry(dev, &bus->devices, bus_list) {
		if (dev->subordinate) {
		if (atomic_read(&dev->enable_cnt) == 0) {
		if (!pci_is_enabled(dev)) {
		retval = pci_enable_device(dev);
		pci_set_master(dev);
		}

drivers/pci/pci-sysfs.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -148,7 +148,7 @@ static ssize_t is_enabled_store(struct device *dev,
		return -EPERM;

		if (!val) {
		if (atomic_read(&pdev->enable_cnt) != 0)
		if (pci_is_enabled(pdev))
		pci_disable_device(pdev);
		else
		result = -EIO;

drivers/pci/pci.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -844,7 +844,7 @@ static int do_pci_enable_device(struct pci_dev *dev, int bars)
		*/
		int pci_reenable_device(struct pci_dev *dev)
		{
		if (atomic_read(&dev->enable_cnt))
		if (pci_is_enabled(dev))
		return do_pci_enable_device(dev, (1 << PCI_NUM_RESOURCES) - 1);
		return 0;
		}
		@@ -1042,7 +1042,7 @@ static void do_pci_disable_device(struct pci_dev *dev)
		*/
		void pci_disable_enabled_device(struct pci_dev *dev)
		{
		if (atomic_read(&dev->enable_cnt))
		if (pci_is_enabled(dev))
		do_pci_disable_device(dev);
		}

drivers/pci/setup-bus.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -144,7 +144,7 @@ static void pci_setup_bridge(struct pci_bus *bus)
		struct pci_bus_region region;
		u32 l, bu, lu, io_upper16;

		if (!pci_is_root_bus(bus) && bus->is_added)
		if (pci_is_enabled(bridge))
		return;

		dev_info(&bridge->dev, "PCI bridge, secondary bus %04x:%02x\n",

include/linux/pci.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -674,6 +674,11 @@ int __must_check pci_reenable_device(struct pci_dev *);
		int __must_check pcim_enable_device(struct pci_dev *pdev);
		void pcim_pin_device(struct pci_dev *pdev);

		static inline int pci_is_enabled(struct pci_dev *pdev)
		{
		return (atomic_read(&pdev->enable_cnt) > 0);
		}

		static inline int pci_is_managed(struct pci_dev *pdev)
		{
		return pdev->is_managed;