From d56aeabac3d163edaacd58eb0854928a479cff84 Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Sat, 6 Sep 2008 15:21:01 +0000
Subject: [PATCH] Document BUS_DMA_NOCACHE.

MFC after:	3 days
---
 share/man/man9/bus_dma.9 | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/share/man/man9/bus_dma.9 b/share/man/man9/bus_dma.9
index b2ab76982703..82eefc49829d 100644
--- a/share/man/man9/bus_dma.9
+++ b/share/man/man9/bus_dma.9
@@ -547,6 +547,13 @@ Are as follows:
 .It Dv BUS_DMA_NOWAIT
 The load should not be deferred in case of insufficient mapping resources,
 and instead should return immediately with an appropriate error.
+.It Dv BUS_DMA_NOCACHE
+The allocated memory will not be cached in the processor caches.
+All memory accesses appear on the bus and are executed
+without reordering.
+Currently, the flag is implemented for i386 and amd64 architectures
+only, where it results in the Strong Uncacheable
+PAT to be set for the allocated virtual address range.
 .El
 .El
 .Pp