From patchwork Thu May 16 06:12:00 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: pekon gupta X-Patchwork-Id: 2575341 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id AC908E00E5 for ; Thu, 16 May 2013 06:12:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754726Ab3EPGMp (ORCPT ); Thu, 16 May 2013 02:12:45 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:37889 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754751Ab3EPGMn (ORCPT ); Thu, 16 May 2013 02:12:43 -0400 Received: from dbdlxv05.itg.ti.com ([172.24.171.60]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id r4G6CEld004369; Thu, 16 May 2013 01:12:15 -0500 Received: from DBDE72.ent.ti.com (dbde72.ent.ti.com [172.24.171.97]) by dbdlxv05.itg.ti.com (8.14.3/8.13.8) with ESMTP id r4G6C9pm032515; Thu, 16 May 2013 01:12:10 -0500 Received: from dbdp32.itg.ti.com (172.24.170.251) by DBDE72.ent.ti.com (172.24.171.97) with Microsoft SMTP Server id 14.2.342.3; Thu, 16 May 2013 14:12:08 +0800 Received: from psplinux064.india.ti.com (smtpvbd.itg.ti.com [172.24.170.250]) by dbdp32.itg.ti.com (8.13.8/8.13.8) with ESMTP id r4G6C5CJ022661; Thu, 16 May 2013 11:42:09 +0530 From: "Gupta, Pekon" To: , CC: "Gupta, Pekon" , , , , Subject: [PATCH 2/2] ARM: OMAP2+: cleaned-up DT support of various ECC schemes Date: Thu, 16 May 2013 11:42:00 +0530 Message-ID: <1368684720-26763-3-git-send-email-pekon@ti.com> X-Mailer: git-send-email 1.8.1 In-Reply-To: <1368684720-26763-1-git-send-email-pekon@ti.com> References: <1368684720-26763-1-git-send-email-pekon@ti.com> MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org From: "Gupta, Pekon" ECC scheme on NAND devices can be implemented in multiple ways.Some using Software algorithm, while others using in-build Hardware engines. omap2-nand driver currently supports following flavours of ECC schemes, selectable via DTB. +---------------------------------------+---------------+---------------+ | ECC scheme |ECC calculation|Error detection| +---------------------------------------+---------------+---------------+ |OMAP_ECC_HAMMING_CODE_DEFAULT |S/W |S/W | |OMAP_ECC_HAMMING_CODE_HW |H/W (GPMC) |S/W | |OMAP_ECC_HAMMING_CODE_HW_ROMCODE |H/W (GPMC) |S/W | +---------------------------------------+---------------+---------------+ |(requires CONFIG_MTD_NAND_ECC_BCH) | | | |OMAP_ECC_BCH8_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W | +---------------------------------------+---------------+---------------+ |(requires CONFIG_MTD_NAND_OMAP_BCH) | | | |OMAP_ECC_BCH8_CODE_HW |H/W (GPMC) |H/W (ELM) | +---------------------------------------+---------------+---------------+ Selection of some ECC schemes also require enabling following Kconfig options. This was done to optimize footprint of omap2-nand driver. -Kconfig:CONFIG_MTD_NAND_ECC_BCH enables S/W based BCH ECC algorithm -Kconfig:CONFIG_MTD_NAND_OMAP_BCH enables H/W based BCH ECC algorithm Signed-off-by: Gupta, Pekon --- .../devicetree/bindings/mtd/gpmc-nand.txt | 37 +++++++++++++++------- arch/arm/boot/dts/am335x-evm.dts | 2 +- arch/arm/mach-omap2/gpmc.c | 12 ++++--- 3 files changed, 34 insertions(+), 17 deletions(-) diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt index e7f8d7e..de180be 100644 --- a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt +++ b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt @@ -17,20 +17,35 @@ Required properties: Optional properties: - - nand-bus-width: Set this numeric value to 16 if the hardware - is wired that way. If not specified, a bus - width of 8 is assumed. + - nand-bus-width: Determines data-width of the connected device + x16 = "16" + x8 = "8" (default) - - ti,nand-ecc-opt: A string setting the ECC layout to use. One of: - "sw" Software method (default) - "hw" Hardware method - "hw-romcode" gpmc hamming mode method & romcode layout - "bch4" 4-bit BCH ecc code - "bch8" 8-bit BCH ecc code + - ti,nand-ecc-opt: Determines the ECC scheme used by driver. + It can be any of the following strings: + + "hamming_sw" 1-bit Hamming ECC using software + + "hamming_hw" 1-bit Hamming ECC using hardware + + "hamming_hw_romcode" 1-bit Hamming ECC using hardware + - ECC layout compatible to ROM code + + "bch8_hw_detection_sw" 8-bit BCH with ECC calculation in hardware + and error detection in software + - requires Kconfig CONFIG_MTD_NAND_ECC_BCH + + "bch8_hw" 8-bit BCH with ECC calculation in hardware + and error detection in hardware + - requires to be specified + - requires Kconfig CONFIG_MTD_NAND_OMAP_BCH + + + + - elm_id: Specifies elm device node. This is required to + support some BCH ECC schemes mentioned above. - - elm_id: Specifies elm device node. This is required to support BCH - error correction using ELM module. For inline partiton table parsing (optional): diff --git a/arch/arm/boot/dts/am335x-evm.dts b/arch/arm/boot/dts/am335x-evm.dts index 0b8f161..60e8f59 100644 --- a/arch/arm/boot/dts/am335x-evm.dts +++ b/arch/arm/boot/dts/am335x-evm.dts @@ -135,7 +135,7 @@ nand@0,0 { reg = <0 0 0>; /* CS0, offset 0 */ nand-bus-width = <8>; - ti,nand-ecc-opt = "bch8"; + ti,nand-ecc-opt = "bch8_hw"; gpmc,sync-clk = <0>; gpmc,cs-on = <0>; diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c index 410e1ba..03b8027 100644 --- a/arch/arm/mach-omap2/gpmc.c +++ b/arch/arm/mach-omap2/gpmc.c @@ -1205,11 +1205,13 @@ static void __maybe_unused gpmc_read_timings_dt(struct device_node *np, #ifdef CONFIG_MTD_NAND static const char * const nand_ecc_opts[] = { - [OMAP_ECC_HAMMING_CODE_DEFAULT] = "sw", - [OMAP_ECC_HAMMING_CODE_HW] = "hw", - [OMAP_ECC_HAMMING_CODE_HW_ROMCODE] = "hw-romcode", - [OMAP_ECC_BCH4_CODE_HW] = "bch4", - [OMAP_ECC_BCH8_CODE_HW] = "bch8", + [OMAP_ECC_HAMMING_CODE_DEFAULT] = "hamming_sw", + [OMAP_ECC_HAMMING_CODE_HW] = "hamming_hw", + [OMAP_ECC_HAMMING_CODE_HW_ROMCODE] = "hamming_hw_romcode", + [OMAP_ECC_BCH4_CODE_HW] = "bch4_hw", + [OMAP_ECC_BCH4_CODE_HW_DETECTION_SW] = "bch4_hw_detection_sw", + [OMAP_ECC_BCH8_CODE_HW] = "bch8_hw", + [OMAP_ECC_BCH8_CODE_HW_DETECTION_SW] = "bch8_hw_detection_sw" }; static int gpmc_probe_nand_child(struct platform_device *pdev,