[PATCH 4/4] mm: Update DMA zones description

[Nicolas Saenz Julienne]

The default behavior for arm64 changed, so reflect that.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
---
 include/linux/mmzone.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index fb3bf696c05e..d28ce77ccc2a 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -363,8 +363,9 @@ enum zone_type {
 	 *  - arm only uses ZONE_DMA, the size, up to 4G, may vary depending on
 	 *    the specific device.
 	 *
-	 *  - arm64 has a fixed 1G ZONE_DMA and ZONE_DMA32 for the rest of the
-	 *    lower 4G.
+	 *  - arm64 uses a single 4GB ZONE_DMA, except on the Raspberry Pi 4,
+	 *    in which ZONE_DMA covers the first GB and ZONE_DMA32 the rest of
+	 *    the lower 4GB.
 	 *
 	 *  - powerpc only uses ZONE_DMA, the size, up to 2G, may vary
 	 *    depending on the specific device.
-- 
2.28.0