mtd: nand: omap2: Fix high memory dma prefetch transfer

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>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index d1496b1276dfce6eb6591f58b6b563aecdb05265..08e158895635cddda0bbea4e6973cfb8dd727e74 100644 (file)
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -473,17 +473,8 @@ 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);