PCI Probe Question

[John Rose]

Hi Greg-

Thanks for responding.  I think Paul answered your other questions
better than I could have :)

> How do you all handle this in your boot up code then?

Not sure I understand what you're asking, but I believe that the
hypervisor only allows access (during scan of the PHB device) to the
devfn's corresponding to the slots that your partition currently owns.

> If you convince me you really have to do this, why duplicate the
> existing pci code in your driver?  How about just creating a
> pci_scan_single_device() function for the pci core that does that logic
> (and make pci_scan_slot() call it.)

Agreed.  I initially wanted to minimize my changes to generic code, but
this looks better.  How's this patch?

Thanks-
John

diff -Nru a/drivers/pci/hotplug/rpadlpar_core.c b/drivers/pci/hotplug/rpadlpar_core.c
--- a/drivers/pci/hotplug/rpadlpar_core.c	Tue Jan 27 14:41:07 2004
+++ b/drivers/pci/hotplug/rpadlpar_core.c	Tue Jan 27 14:41:07 2004
@@ -143,9 +143,9 @@
 	struct pci_controller *hose = dn->phb;
 	struct pci_dev *dev = NULL;

-	/* Scan phb bus for devices, adding new ones to bus->devices */
-	if (!pci_scan_slot(hose->bus, dn->devfn)) {
-		printk(KERN_ERR "%s: found no devices on bus\n", __FUNCTION__);
+	/* Scan phb bus for EADS device, adding new one to bus->devices */
+	if (!pci_scan_single_device(hose->bus, dn->devfn)) {
+		printk(KERN_ERR "%s: found no device on bus\n", __FUNCTION__);
 		return NULL;
 	}

diff -Nru a/drivers/pci/probe.c b/drivers/pci/probe.c
--- a/drivers/pci/probe.c	Tue Jan 27 14:41:07 2004
+++ b/drivers/pci/probe.c	Tue Jan 27 14:41:07 2004
@@ -535,6 +535,30 @@
 	return dev;
 }

+struct pci_dev * __devinit
+pci_scan_single_device(struct pci_bus *bus, int devfn)
+{
+	struct pci_dev *dev;
+
+	dev = pci_scan_device(bus, devfn);
+	pci_scan_msi_device(dev);
+
+	if (!dev)
+		return NULL;
+
+	/* Fix up broken headers */
+	pci_fixup_device(PCI_FIXUP_HEADER, dev);
+
+	/*
+	 * Add the device to our list of discovered devices
+	 * and the bus list for fixup functions, etc.
+	 */
+	INIT_LIST_HEAD(&dev->global_list);
+	list_add_tail(&dev->bus_list, &bus->devices);
+
+	return dev;
+}
+
 /**
  * pci_scan_slot - scan a PCI slot on a bus for devices.
  * @bus: PCI bus to scan
@@ -551,39 +575,17 @@
 	for (func = 0; func < 8; func++, devfn++) {
 		struct pci_dev *dev;

-		dev = pci_scan_device(bus, devfn);
-		pci_scan_msi_device(dev);
-#if 0
-		if (func == 0) {
-			if (!dev)
+		dev = pci_scan_single_device(bus, devfn);
+		if (dev) {
+			nr++;
+
+			/*
+		 	 * If this is a single function device,
+		 	 * don't scan past the first function.
+		 	 */
+			if (!dev->multifunction)
 				break;
-		} else {
-			if (!dev)
-				continue;
-			dev->multifunction = 1;
 		}
-#else
-		if (!dev)
-			continue;
-#endif
-
-		/* Fix up broken headers */
-		pci_fixup_device(PCI_FIXUP_HEADER, dev);
-
-		/*
-		 * Add the device to our list of discovered devices
-		 * and the bus list for fixup functions, etc.
-		 */
-		INIT_LIST_HEAD(&dev->global_list);
-		list_add_tail(&dev->bus_list, &bus->devices);
-		nr++;
-
-		/*
-		 * If this is a single function device,
-		 * don't scan past the first function.
-		 */
-		if (!dev->multifunction)
-			break;
 	}
 	return nr;
 }
@@ -686,4 +688,5 @@
 EXPORT_SYMBOL(pci_do_scan_bus);
 EXPORT_SYMBOL(pci_scan_slot);
 EXPORT_SYMBOL(pci_scan_bridge);
+EXPORT_SYMBOL(pci_scan_single_device);
 #endif
diff -Nru a/include/linux/pci.h b/include/linux/pci.h
--- a/include/linux/pci.h	Tue Jan 27 14:41:07 2004
+++ b/include/linux/pci.h	Tue Jan 27 14:41:07 2004
@@ -585,6 +585,7 @@
 	return pci_scan_bus_parented(NULL, bus, ops, sysdata);
 }
 int pci_scan_slot(struct pci_bus *bus, int devfn);
+struct pci_dev * pci_scan_single_device(struct pci_bus *bus, int devfn);
 void pci_bus_add_devices(struct pci_bus *bus);
 void pci_name_device(struct pci_dev *dev);
 char *pci_class_name(u32 class);


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