[PATCH 2/2] mtd: nand: omap2: Fix high memory dma prefetch transfer

From	Franklin S Cooper Jr <fcooper@ti.com>
Newsgroups	linux.kernel
Subject	[PATCH 2/2] mtd: nand: omap2: Fix high memory dma prefetch transfer
Date	2016-04-15 22:30 +0200
Message-ID	<roixk-pK-21@gated-at.bofh.it> (permalink)
References	<roixj-pK-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: "Cooper Jr., Franklin" <fcooper@ti.com>

Based on DMA documentation and testing using high memory buffer when doing
dma transfers can lead to various issues including kernel panics.

To workaround this simply use cpu copy.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
---
 drivers/mtd/nand/omap2.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 762e0ed..8d0ae3a 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -467,17 +467,8 @@ static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
 	int ret;
 	u32 val;
 
-	if (addr >= high_memory) {
-		struct page *p1;
-
-		if (((size_t)addr & PAGE_MASK) !=
-			((size_t)(addr + len - 1) & PAGE_MASK))
-			goto out_copy;
-		p1 = vmalloc_to_page(addr);
-		if (!p1)
-			goto out_copy;
-		addr = page_address(p1) + ((size_t)addr & ~PAGE_MASK);
-	}
+	if (!virt_addr_valid(addr))
+		goto out_copy;
 
 	sg_init_one(&sg, addr, len);
 	n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);
-- 
2.7.0

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[PATCH 2/2] mtd: nand: omap2: Fix high memory dma prefetch transfer Franklin S Cooper Jr <fcooper@ti.com> - 2016-04-15 22:30 +0200

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