Re: [PATCH] PCI fixes for 2.6.10-rc1

Greg KH
2004-11-12T23:41:52Z

ChangeSet 1.2091.1.3, 2004/11/11 16:33:31-08:00, jdittmer@ppp0.net

[PATCH] fakephp: add pci bus rescan ability

This adds the ability to rescan the pci bus for newly inserted,
reprogrammed or previously disabled pci devices.
To initiate a rescan you need to write '1' to any of the
/sys/bus/pci/slots/*/power control files. No known pci devices
will be touched.
Additionally this fixes a bug, when someone tries to disable
a device with subfunctions. The subfunctions will be disabled first now.

Short demo:
# modprobe fakephp
# ls /sys/bus/pci/slots | grep "0000:04"
0000:04:02.0
0000:04:02.1
0000:04:02.2
0000:04:03.0
0000:04:03.1
# echo -n 0 > /sys/bus/pci/slots/0000\:04\:02.0/power
# ls /sys/bus/pci/slots | grep "0000:04"
0000:04:03.0
0000:04:03.1
# echo -n 1 > /sys/bus/pci/slots/0000\:03\:01.0/power
# ls /sys/bus/pci/slots | grep "0000:04"
0000:04:02.0
0000:04:02.1
0000:04:02.2
0000:04:03.0
0000:04:03.1
# lspci | grep "0000:04"
0000:04:02.0 Multimedia audio controller: Creative Labs SB Audigy (rev 03)
0000:04:02.1 Input device controller: Creative Labs SB Audigy MIDI/Gameport (rev 03)
0000:04:02.2 FireWire (IEEE 1394): Creative Labs SB Audigy FireWire Port
0000:04:03.0 SCSI storage controller: Adaptec AHA-3960D / AIC-7899A U160/m (rev 01)
0000:04:03.1 SCSI storage controller: Adaptec AHA-3960D / AIC-7899A U160/m (rev 01)

Signed-off-by: Jan Dittmer <jdittmer@ppp0.net>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/pci/hotplug/fakephp.c | 126 ++++++++++++++++++++++++++++++++++++++++++
1 files changed, 126 insertions(+)

diff -Nru a/drivers/pci/hotplug/fakephp.c b/drivers/pci/hotplug/fakephp.c
--- a/drivers/pci/hotplug/fakephp.c 2004-11-12 15:11:41 -08:00
+++ b/drivers/pci/hotplug/fakephp.c 2004-11-12 15:11:41 -08:00
@@ -165,14 +165,123 @@
err("Problem unregistering a slot %s\n", dslot->slot->name);
}

+/**
+ * Rescan slot.
+ * Tries hard not to re-enable already existing devices
+ * also handles scanning of subfunctions
+ *
+ * @param temp Device template. Should be set: bus and devfn.
+ */
+static void pci_rescan_slot(struct pci_dev *temp)
+{
+ struct pci_bus *bus = temp->bus;
+ struct pci_dev *dev;
+ int func;
+ u8 hdr_type;
+ if (!pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type)) {
+ temp->hdr_type = hdr_type & 0x7f;
+ if (!pci_find_slot(bus->number, temp->devfn)) {
+ dev = pci_scan_single_device(bus, temp->devfn);
+ if (dev) {
+ dbg("New device on %s function %x:%x\n",
+ bus->name, temp->devfn >> 3,
+ temp->devfn & 7);
+ pci_bus_add_device(dev);
+ add_slot(dev);
+ }
+ }
+ /* multifunction device? */
+ if (!(hdr_type & 0x80))
+ return;
+
+ /* continue scanning for other functions */
+ for (func = 1, temp->devfn++; func < 8; func++, temp->devfn++) {
+ if (pci_read_config_byte(temp, PCI_HEADER_TYPE, &hdr_type))
+ continue;
+ temp->hdr_type = hdr_type & 0x7f;
+
+ if (!pci_find_slot(bus->number, temp->devfn)) {
+ dev = pci_scan_single_device(bus, temp->devfn);
+ if (dev) {
+ dbg("New device on %s function %x:%x\n",
+ bus->name, temp->devfn >> 3,
+ temp->devfn & 7);
+ pci_bus_add_device(dev);
+ add_slot(dev);
+ }
+ }
+ }
+ }
+}
+
+
+/**
+ * Rescan PCI bus.
+ * call pci_rescan_slot for each possible function of the bus
+ *
+ * @param bus
+ */
+static void pci_rescan_bus(const struct pci_bus *bus)
+{
+ unsigned int devfn;
+ struct pci_dev *dev;
+ dev = kmalloc(sizeof(struct pci_dev), GFP_KERNEL);
+ if (!dev)
+ return;
+
+ memset(dev, 0, sizeof(dev));
+ dev->bus = (struct pci_bus*)bus;
+ dev->sysdata = bus->sysdata;
+ for (devfn = 0; devfn < 0x100; devfn += 8) {
+ dev->devfn = devfn;
+ pci_rescan_slot(dev);
+ }
+ kfree(dev);
+}
+
+/* recursively scan all buses */
+static void pci_rescan_buses(const struct list_head *list)
+{
+ const struct list_head *l;
+ list_for_each(l,list) {
+ const struct pci_bus *b = pci_bus_b(l);
+ pci_rescan_bus(b);
+ pci_rescan_buses(&b->children);
+ }
+}
+
+/* initiate rescan of all pci buses */
+static inline void pci_rescan(void) {
+ pci_rescan_buses(&pci_root_buses);
+}
+
+
static int enable_slot(struct hotplug_slot *hotplug_slot)
{
+ /* mis-use enable_slot for rescanning of the pci bus */
+ pci_rescan();
return -ENODEV;
}

+/* find the hotplug_slot for the pci_dev */
+static struct hotplug_slot *get_slot_from_dev(struct pci_dev *dev)
+{
+ struct dummy_slot *dslot;
+
+ list_for_each_entry(dslot, &slot_list, node) {
+ if (dslot->dev == dev)
+ return dslot->slot;
+ }
+ return NULL;
+}
+
+
static int disable_slot(struct hotplug_slot *slot)
{
struct dummy_slot *dslot;
+ struct hotplug_slot *hslot;
+ struct pci_dev *dev;
+ int func;

if (!slot)
return -ENODEV;
@@ -184,6 +293,23 @@
if (dslot->dev->subordinate) {
err("Can't remove PCI devices with other PCI devices behind it yet.\n");
return -ENODEV;
+ }
+ /* search for subfunctions and disable them first */
+ if (!(dslot->dev->devfn & 7)) {
+ for (func = 1; func < 8; func++) {
+ dev = pci_find_slot(dslot->dev->bus->number,
+ dslot->dev->devfn + func);
+ if (dev) {
+ hslot = get_slot_from_dev(dev);
+ if (hslot)
+ disable_slot(hslot);
+ else {
+ err("Hotplug slot not found for subfunction of PCI device\n");
+ return -ENODEV;
+ }
+ } else
+ dbg("No device in slot found\n");
+ }
}

/* remove the device from the pci core */