arm: a37xx: Remap IO space to bus address 0x0
Remap PCI I/O space to the bus address 0x0 in the Armada 37xx device-tree
in order to support legacy I/O port based cards which have hardcoded I/O
ports in low address space.
Some legacy PCI I/O based cards do not support 32-bit I/O addressing.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/arch/arm/dts/armada-3720-turris-mox.dts b/arch/arm/dts/armada-3720-turris-mox.dts
index 1fc4a30..595b4b5 100644
--- a/arch/arm/dts/armada-3720-turris-mox.dts
+++ b/arch/arm/dts/armada-3720-turris-mox.dts
@@ -139,7 +139,9 @@
/*
* U-Boot port for Turris Mox has a bug which always expects that "ranges" DT property
* contains exactly 2 ranges with 3 (child) address cells, 2 (parent) address cells and
- * 2 size cells and also expects that the second range starts at 16 MB offset. If these
+ * 2 size cells and also expects that the second range starts at 16 MB offset. Also it
+ * expects that first range uses same address for PCI (child) and CPU (parent) cells (so
+ * no remapping) and that this address is the lowest from all specified ranges. If these
* conditions are not met then U-Boot crashes during loading kernel DTB file. PCIe address
* space is 128 MB long, so the best split between MEM and IO is to use fixed 16 MB window
* for IO and the rest 112 MB (64+32+16) for MEM. Controller supports 32-bit IO mapping.
@@ -148,6 +150,9 @@
* https://source.denx.de/u-boot/u-boot/-/commit/cb2ddb291ee6fcbddd6d8f4ff49089dfe580f5d7
* https://source.denx.de/u-boot/u-boot/-/commit/c64ac3b3185aeb3846297ad7391fc6df8ecd73bf
* https://source.denx.de/u-boot/u-boot/-/commit/4a82fca8e330157081fc132a591ebd99ba02ee33
+ * Bug related to requirement of same child and parent addresses for first range is fixed
+ * in U-Boot version 2022.04 by following commit:
+ * https://source.denx.de/u-boot/u-boot/-/commit/1fd54253bca7d43d046bba4853fe5fafd034bc17
*/
#address-cells = <3>;
#size-cells = <2>;