[U-Boot-Users] [PATCH] Avoid assigning PCI resources from zero address

Sergei Shtylyov sshtylyov at ru.mvista.com
Wed Dec 27 21:13:51 CET 2006

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 at ru.mvista.com>

 drivers/pci_auto.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletion(-)

Index: u-boot/drivers/pci_auto.c
--- u-boot.orig/drivers/pci_auto.c
+++ u-boot/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)

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