From: Ralf Baechle <ralf@linux-mips.org>
Date: Tue, 11 Nov 2014 21:22:03 +0000 (+0100)
Subject: MIPS: DMA: Explain the lack of special handling for R14000/R16000.
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0dc294c05d9df09ca4a65071e370247eaab8638d;p=linux-beck.git

MIPS: DMA: Explain the lack of special handling for R14000/R16000.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---

diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index 33ba3c558fe4..af5f046e627e 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -61,6 +61,11 @@ static inline struct page *dma_addr_to_page(struct device *dev,
  * Warning on the terminology - Linux calls an uncached area coherent;
  * MIPS terminology calls memory areas with hardware maintained coherency
  * coherent.
+ *
+ * Note that the R14000 and R16000 should also be checked for in this
+ * condition.  However this function is only called on non-I/O-coherent
+ * systems and only the R10000 and R12000 are used in such systems, the
+ * SGI IP28 Indigo² rsp. SGI IP32 aka O2.
  */
 static inline int cpu_needs_post_dma_flush(struct device *dev)
 {