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authorYinghai Lu <yinghai@kernel.org>2015-01-15 16:21:49 -0600
committerBjorn Helgaas <bhelgaas@google.com>2015-01-16 10:04:42 -0600
commit0f7e7aee2f37119a32e6e8b63250922442528961 (patch)
tree4bb354ba434d5870c08b16440183792ff717b3d6 /drivers/pci/bus.c
parent3f2f4dc456e9f80849b99d79600a7257690ca4b1 (diff)
downloadlinux-0f7e7aee2f37119a32e6e8b63250922442528961.tar.bz2
PCI: Add pci_bus_clip_resource() to clip to fit upstream window
Add pci_bus_clip_resource(). If a PCI-PCI bridge window overlaps an upstream bridge window but is not completely contained by it, this clips the downstream window so it fits inside the upstream one. No functional change (this adds the function but no callers). [bhelgaas: changelog, split into separate patch] 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> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.16+
Diffstat (limited to 'drivers/pci/bus.c')
-rw-r--r--drivers/pci/bus.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 73aef51a28f0..8fb16188cd82 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -228,6 +228,49 @@ int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
}
EXPORT_SYMBOL(pci_bus_alloc_resource);
+/*
+ * The @idx resource of @dev should be a PCI-PCI bridge window. If this
+ * resource fits inside a window of an upstream bridge, do nothing. If it
+ * overlaps an upstream window but extends outside it, clip the resource so
+ * it fits completely inside.
+ */
+bool pci_bus_clip_resource(struct pci_dev *dev, int idx)
+{
+ struct pci_bus *bus = dev->bus;
+ struct resource *res = &dev->resource[idx];
+ struct resource orig_res = *res;
+ struct resource *r;
+ int i;
+
+ pci_bus_for_each_resource(bus, r, i) {
+ resource_size_t start, end;
+
+ if (!r)
+ continue;
+
+ if (resource_type(res) != resource_type(r))
+ continue;
+
+ start = max(r->start, res->start);
+ end = min(r->end, res->end);
+
+ if (start > end)
+ continue; /* no overlap */
+
+ if (res->start == start && res->end == end)
+ return false; /* no change */
+
+ res->start = start;
+ res->end = end;
+ dev_printk(KERN_DEBUG, &dev->dev, "%pR clipped to %pR\n",
+ &orig_res, res);
+
+ return true;
+ }
+
+ return false;
+}
+
void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
/**