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Commit 705b1aaa authored by Alex Chiang's avatar Alex Chiang Committed by Jesse Barnes
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PCI: Introduce /sys/bus/pci/rescan 



This interface allows the user to force a rescan of all PCI buses
in system, and rediscover devices that have been removed earlier.

pci_bus_attrs implementation from Trent Piepho.

Thanks to Vegard Nossum for discovering locking issues with the
sysfs interface.

Cc: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: default avatarAlex Chiang <achiang@hp.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 3ed4fd96

Documentation/ABI/testing/sysfs-bus-pci

+9 −0
Original line number Diff line number Diff line
@@ -57,6 +57,15 @@ Description: 
		match the driver to the device.  For example:

		# echo "8086 10f5" > /sys/bus/pci/drivers/foo/remove_id



What:		/sys/bus/pci/rescan

Date:		January 2009

Contact:	Linux PCI developers <linux-pci@vger.kernel.org>

Description:

		Writing a non-zero value to this attribute will

		force a rescan of all PCI buses in the system, and

		re-discover previously removed devices.

		Depends on CONFIG_HOTPLUG.



What:		/sys/bus/pci/devices/.../vpd

Date:		February 2008

Contact:	Ben Hutchings <bhutchings@solarflare.com>

drivers/pci/pci-driver.c

+1 −0
Original line number Diff line number Diff line
@@ -1049,6 +1049,7 @@ struct bus_type pci_bus_type = { 
	.remove		= pci_device_remove,

	.shutdown	= pci_device_shutdown,

	.dev_attrs	= pci_dev_attrs,

	.bus_attrs	= pci_bus_attrs,

	.pm		= PCI_PM_OPS_PTR,

};

drivers/pci/pci-sysfs.c

+26 −0
Original line number Diff line number Diff line
@@ -219,6 +219,32 @@ msi_bus_store(struct device *dev, struct device_attribute *attr, 
	return count;

}



#ifdef CONFIG_HOTPLUG

static DEFINE_MUTEX(pci_remove_rescan_mutex);

static ssize_t bus_rescan_store(struct bus_type *bus, const char *buf,

				size_t count)

{

	unsigned long val;

	struct pci_bus *b = NULL;



	if (strict_strtoul(buf, 0, &val) < 0)

		return -EINVAL;



	if (val) {

		mutex_lock(&pci_remove_rescan_mutex);

		while ((b = pci_find_next_bus(b)) != NULL)

			pci_rescan_bus(b);

		mutex_unlock(&pci_remove_rescan_mutex);

	}

	return count;

}



struct bus_attribute pci_bus_attrs[] = {

	__ATTR(rescan, (S_IWUSR|S_IWGRP), NULL, bus_rescan_store),

	__ATTR_NULL

};

#endif



struct device_attribute pci_dev_attrs[] = {

	__ATTR_RO(resource),

	__ATTR_RO(vendor),

drivers/pci/pci.h

+6 −0
Original line number Diff line number Diff line
@@ -138,6 +138,12 @@ extern int pcie_mch_quirk; 
extern struct device_attribute pci_dev_attrs[];

extern struct device_attribute dev_attr_cpuaffinity;

extern struct device_attribute dev_attr_cpulistaffinity;

#ifdef CONFIG_HOTPLUG

extern struct bus_attribute pci_bus_attrs[];

#else

#define pci_bus_attrs	NULL

#endif





/**

 * pci_match_one_device - Tell if a PCI device structure has a matching

drivers/pci/probe.c

+2 −2
Original line number Diff line number Diff line
@@ -1228,13 +1228,13 @@ unsigned int __devinit pci_rescan_bus(struct pci_bus *bus) 


	max = pci_scan_child_bus(bus);



	up_read(&pci_bus_sem);

	down_read(&pci_bus_sem);

	list_for_each_entry(dev, &bus->devices, bus_list)

		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||

		    dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)

			if (dev->subordinate)

				pci_bus_size_bridges(dev->subordinate);

	down_read(&pci_bus_sem);

	up_read(&pci_bus_sem);



	pci_bus_assign_resources(bus);

	pci_enable_bridges(bus);