PCI: add generic pci_enable_resources()

Each architecture has its own pcibios_enable_resources() implementation.
These differ in many minor ways that have nothing to do with actual
architectural differences.  Follow-on patches will make most arches
use this generic version instead.

This version is based on powerpc, which seemed most up-to-date.  The only
functional difference from the x86 version is that this uses "!r->parent"
to check for resource collisions instead of "!r->start && r->end".

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/setup-res.c

@@ -263,3 +263,46 @@ void pdev_sort_resources(struct pci_dev *dev, struct resource_list *head)
 		}
 	}
 }
+
+int pci_enable_resources(struct pci_dev *dev, int mask)
+{
+	u16 cmd, old_cmd;
+	int i;
+	struct resource *r;
+
+	pci_read_config_word(dev, PCI_COMMAND, &cmd);
+	old_cmd = cmd;
+
+	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+		if (!(mask & (1 << i)))
+			continue;
+
+		r = &dev->resource[i];
+
+		if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
+			continue;
+		if ((i == PCI_ROM_RESOURCE) &&
+				(!(r->flags & IORESOURCE_ROM_ENABLE)))
+			continue;
+
+		if (!r->parent) {
+			dev_err(&dev->dev, "device not available because of "
+				"BAR %d [%llx:%llx] collisions\n", i,
+				(unsigned long long) r->start,
+				(unsigned long long) r->end);
+			return -EINVAL;
+		}
+
+		if (r->flags & IORESOURCE_IO)
+			cmd |= PCI_COMMAND_IO;
+		if (r->flags & IORESOURCE_MEM)
+			cmd |= PCI_COMMAND_MEMORY;
+	}
+
+	if (cmd != old_cmd) {
+		dev_info(&dev->dev, "enabling device (%04x -> %04x)\n",
+			 old_cmd, cmd);
+		pci_write_config_word(dev, PCI_COMMAND, cmd);
+	}
+	return 0;
+}

include/linux/pci.h

@@ -624,6 +624,7 @@ int pci_claim_resource(struct pci_dev *, int);
 void pci_assign_unassigned_resources(void);
 void pdev_enable_device(struct pci_dev *);
 void pdev_sort_resources(struct pci_dev *, struct resource_list *);
+int pci_enable_resources(struct pci_dev *, int mask);
 void pci_fixup_irqs(u8 (*)(struct pci_dev *, u8 *),
 		    int (*)(struct pci_dev *, u8, u8));
 #define HAVE_PCI_REQ_REGIONS	2