[PATCH] Avoid assigning PCI resources from zero address

If a PCI IDE card happens to get a zero address assigned to it, the Linux IDE
core complains and IDE drivers fails to work.  Also, assigning zero to a BAR
was illegal according to PCI 2.1 (the later revisions seem to have excluded the
sentence about "0" being considered an invalid address) -- so, use a reasonable
starting value of 0x1000 (that's what the most Linux archs are using).

Alternatively, one might have fixed the calls to pci_set_region() individually
(some code even seems to have taken care of this issue) but that would have
been a lot more work. :-)

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: Stefan Roese <sr@denx.de>

diff --git a/drivers/pci_auto.c b/drivers/pci_auto.c
index 969167555ea27369008b7c5b53dc76f75bc9a46f..f170c2db89e066420771a5fbb813385905c9baf2 100644 (file)
--- a/drivers/pci_auto.c
+++ b/drivers/pci_auto.c
@@ -34,7 +34,12 @@
 
 void pciauto_region_init(struct pci_region* res)
 {
-       res->bus_lower = res->bus_start;
+       /*
+        * Avoid allocating PCI resources from address 0 -- this is illegal
+        * according to PCI 2.1 and moreover, this is known to cause Linux IDE
+        * drivers to fail. Use a reasonable starting value of 0x1000 instead.
+        */
+       res->bus_lower = res->bus_start ? res->bus_start : 0x1000;
 }
 
 void pciauto_region_align(struct pci_region *res, unsigned long size)