fdt: Support for ISA busses
Support ISA busses in much the same way as Linux does. This allows for
ISA bus addresses to be translated, and only if CONFIG_OF_ISA_BUS is
selected in order to avoid including the code in builds which won't need
it.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
index c5c9d2a..8749561 100644
--- a/drivers/core/Kconfig
+++ b/drivers/core/Kconfig
@@ -178,4 +178,27 @@
used for the address translation. This function is faster and
smaller in size than fdt_translate_address().
+config OF_ISA_BUS
+ bool
+ depends on OF_TRANSLATE
+ help
+ Is this option is enabled then support for the ISA bus will
+ be included for addresses read from DT. This is something that
+ should be known to be required or not based upon the board
+ being targetted, and whether or not it makes use of an ISA bus.
+
+ The bus is matched based upon its node name equalling "isa". The
+ busses #address-cells should equal 2, with the first cell being
+ used to hold flags & flag 0x1 indicating that the address range
+ should be accessed using I/O port in/out accessors. The second
+ cell holds the offset into ISA bus address space. The #size-cells
+ property should equal 1, and of course holds the size of the
+ address range used by a device.
+
+ If this option is not enabled then support for the ISA bus is
+ not included and any such busses used in DT will be treated as
+ typical simple-bus compatible busses. This will lead to
+ mistranslation of device addresses, so ensure that this is
+ enabled if your board does include an ISA bus.
+
endmenu