From patchwork Fri Aug 17 13:22:32 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roese X-Patchwork-Id: 1338531 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id 706F3DF266 for ; Fri, 17 Aug 2012 13:27:45 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1T2MY7-0003R1-Hl; Fri, 17 Aug 2012 13:25:15 +0000 Received: from mo6-p05-ob.rzone.de ([2a01:238:20a:202:5305::1]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1T2MXx-0003MQ-Ei; Fri, 17 Aug 2012 13:25:07 +0000 X-RZG-AUTH: :IW0NeWC7b/q2i6W/qstXb1SBUuFnrGohdvpEkce+Ub40Q/uAFj+9EbzQWz+D0YqO X-RZG-CLASS-ID: mo05 Received: from ubuntu-2012.fritz.box (pD9FFB7BC.dip.t-dialin.net [217.255.183.188]) by smtp.strato.de (josoe mo82) (RZmta 30.9 DYNA|AUTH) with ESMTPA id J030d5o7HAt6ms ; Fri, 17 Aug 2012 15:22:32 +0200 (CEST) From: Stefan Roese To: linux-mtd@lists.infradead.org Subject: [PATCH v2] mtd: physmap_of: Add "no-unaligned-direct-access" DT property Date: Fri, 17 Aug 2012 15:22:32 +0200 Message-Id: <1345209752-22938-1-git-send-email-sr@denx.de> X-Mailer: git-send-email 1.7.11.3 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -1.9 (-) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-1.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: devicetree-discuss@ozlabs.org, Artem Bityutskiy , Albrecht Dress , Anatolij Gustschin , David Woodhouse , Stephan Gatzka , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org On some platforms (e.g. MPC5200) a direct 1:1 mapping may cause problems with JFFS2 usage, as the local bus (LPB) doesn't support unaligned accesses as implemented in the JFFS2 code via memcpy(). By defining "no-unaligned-direct-access", the flash will not be exposed directly to the MTD users (e.g. JFFS2) any more. Signed-off-by: Stefan Roese Cc: Stephan Gatzka Cc: Anatolij Gustschin Cc: Albrecht Dress Cc: Artem Bityutskiy Cc: David Woodhouse --- v2: - Changed "map-indirect" to "no-unaligned-direct-access" because of David's comments. Documentation/devicetree/bindings/mtd/mtd-physmap.txt | 7 +++++++ drivers/mtd/maps/physmap_of.c | 14 ++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/Documentation/devicetree/bindings/mtd/mtd-physmap.txt b/Documentation/devicetree/bindings/mtd/mtd-physmap.txt index a63c2bd7..94de19b 100644 --- a/Documentation/devicetree/bindings/mtd/mtd-physmap.txt +++ b/Documentation/devicetree/bindings/mtd/mtd-physmap.txt @@ -16,6 +16,13 @@ file systems on embedded devices. - #address-cells, #size-cells : Must be present if the device has sub-nodes representing partitions (see below). In this case both #address-cells and #size-cells must be equal to 1. + - no-unaligned-direct-access: boolean to disable the default direct + mapping of the flash. + On some platforms (e.g. MPC5200) a direct 1:1 mapping may cause + problems with JFFS2 usage, as the local bus (LPB) doesn't support + unaligned accesses as implemented in the JFFS2 code via memcpy(). + By defining "no-unaligned-direct-access", the flash will not be + exposed directly to the MTD users (e.g. JFFS2) any more. For JEDEC compatible devices, the following additional properties are defined: diff --git a/drivers/mtd/maps/physmap_of.c b/drivers/mtd/maps/physmap_of.c index 2e6fb68..6f19aca 100644 --- a/drivers/mtd/maps/physmap_of.c +++ b/drivers/mtd/maps/physmap_of.c @@ -169,6 +169,7 @@ static int __devinit of_flash_probe(struct platform_device *dev) struct mtd_info **mtd_list = NULL; resource_size_t res_size; struct mtd_part_parser_data ppdata; + bool map_indirect; match = of_match_device(of_flash_match, &dev->dev); if (!match) @@ -192,6 +193,8 @@ static int __devinit of_flash_probe(struct platform_device *dev) } count /= reg_tuple_size; + map_indirect = of_property_read_bool(dp, "no-unaligned-direct-access"); + err = -ENOMEM; info = kzalloc(sizeof(struct of_flash) + sizeof(struct of_flash_list) * count, GFP_KERNEL); @@ -247,6 +250,17 @@ static int __devinit of_flash_probe(struct platform_device *dev) simple_map_init(&info->list[i].map); + /* + * On some platforms (e.g. MPC5200) a direct 1:1 mapping + * may cause problems with JFFS2 usage, as the local bus (LPB) + * doesn't support unaligned accesses as implemented in the + * JFFS2 code via memcpy(). By setting NO_XIP, the + * flash will not be exposed directly to the MTD users + * (e.g. JFFS2) any more. + */ + if (map_indirect) + info->list[i].map.phys = NO_XIP; + if (probe_type) { info->list[i].mtd = do_map_probe(probe_type, &info->list[i].map);