From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752982AbbJORih (ORCPT ); Thu, 15 Oct 2015 13:38:37 -0400 Received: from mail-ob0-f169.google.com ([209.85.214.169]:34675 "EHLO mail-ob0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752290AbbJORhk (ORCPT ); Thu, 15 Oct 2015 13:37:40 -0400 From: Franklin S Cooper Jr To: linux-kernel@vger.kernel.org, rogerq@ti.com, devicetree@vger.kernel.org, linux-omap@vger.kernel.org, linux-mtd@lists.infradead.org, nsekhar@ti.com, computersforpeace@gmail.com, dwmw2@infradead.org, tony@atomide.com Cc: Franklin S Cooper Jr Subject: [PATCH v2 3/5] mtd: nand: omap2: Fix high memory dma prefetch transfer Date: Thu, 15 Oct 2015 12:37:26 -0500 Message-Id: <1444930648-19313-4-git-send-email-fcooper@ti.com> X-Mailer: git-send-email 2.6.1 In-Reply-To: <1444930648-19313-1-git-send-email-fcooper@ti.com> References: <1444930648-19313-1-git-send-email-fcooper@ti.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. The amount of high memory buffers used are very uncommon so no noticeable performance hit should be seen. Signed-off-by: Franklin S Cooper Jr --- V2 Changes: None drivers/mtd/nand/omap2.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-) diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index 1f58420..0d2cbb0 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -479,17 +479,8 @@ 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 (addr >= high_memory) + goto out_copy; sg_init_one(&sg, addr, len); n = dma_map_sg(info->dma->device->dev, &sg, 1, dir); @@ -546,6 +537,7 @@ out_copy: else is_write == 0 ? omap_read_buf8(mtd, (u_char *) addr, len) : omap_write_buf8(mtd, (u_char *) addr, len); + return 0; } -- 2.6.1