powerpc/pseries: Add support for dynamic dma windows

If firmware allows us to map all of a partition's memory for DMA on a
particular bridge, create a 1:1 mapping of that memory. Add hooks for
dealing with hotplug events. Dynamic DMA windows can use larger than the
default page size, and we use the largest one possible.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index f4a04c0c7edc..b245ce61ecb8 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -626,6 +626,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
         disable=        [IPV6]
                         See Documentation/networking/ipv6.txt.
 
+        disable_ddw     [PPC/PSERIES]
+                        Disable Dynamic DMA Window support. Use this if
+                        to workaround buggy firmware.
+
         disable_ipv6=   [IPV6]
                         See Documentation/networking/ipv6.txt.