[PATCH 08/10] PCI, parisc: clip firmware assigned resource under parent bridge's

[Yinghai Lu <yinghai@kernel.org>]

Some bios put range that is not fully coverred by root bus resources.
Try to clip them and update them in pci bridge bars.

We'd like to fix other arches instead of just x86.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=85491
Reported-by: Marek Kordik <kordikmarek@gmail.com>
Fixes: 5b28541552ef ("PCI: Restrict 64-bit prefetchable bridge windows to 64-bit resources")
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
---
 drivers/parisc/lba_pci.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/parisc/lba_pci.c b/drivers/parisc/lba_pci.c
index 37e71ff..e6ab352 100644
--- a/drivers/parisc/lba_pci.c
+++ b/drivers/parisc/lba_pci.c
@@ -692,11 +692,25 @@ lba_fixup_bus(struct pci_bus *bus)
 	*/
 	if (bus->parent) {
 		int i;
+		bool changed = false;
+
+		dev = bus->self;
 		/* PCI-PCI Bridge */
 		pci_read_bridge_bases(bus);
 		for (i = PCI_BRIDGE_RESOURCES; i < PCI_NUM_RESOURCES; i++) {
-			pci_claim_resource(bus->self, i);
+			struct resource *res = &dev->resource[i];
+
+			if (pci_claim_resource(dev, i) >= 0)
+				continue;
+
+			if (pci_bus_clip_resource(dev, res)) {
+				changed = true;
+				if (pci_claim_resource(dev, i) >= 0)
+					continue;
+			}
 		}
+		if (changed)
+			pci_setup_bridge(bus);
 	} else {
 		/* Host-PCI Bridge */
 		int err;
@@ -776,7 +790,15 @@ lba_fixup_bus(struct pci_bus *bus)
 			** that share expansion ROMs (think quad tulip), but
 			** isn't harmful.
 			*/
-			pci_claim_resource(dev, i);
+			if (pci_claim_resource(dev, i) >= 0)
+				continue;
+
+			/* try again with clip */
+			if (i != PCI_ROM_RESOURCE &&
+			    pci_bus_clip_resource(dev, res)) {
+				pci_update_resource(dev, i);
+				pci_claim_resource(dev, i);
+			}
 		}
 
 #ifdef FBB_SUPPORT
-- 
1.8.4.5