From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from comal.ext.ti.com ([198.47.26.152]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wigfa-0001JH-Db for linux-mtd@lists.infradead.org; Fri, 09 May 2014 09:00:42 +0000 From: Pekon Gupta To: Tony Lindgren , Brian Norris Subject: [PATCH v3 0/4] mtd: nand: omap: add support for BCH16_ECC Date: Fri, 9 May 2014 14:29:11 +0530 Message-ID: <1399625955-20882-1-git-send-email-pekon@ti.com> MIME-Version: 1.0 Content-Type: text/plain Cc: linux-omap , Felipe Balbi , linux-mtd , Pekon Gupta , Ezequiel Garcia , Stefan Roese List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , (re-sending as forgot to loop in linux-omap and Tony Lindgren ) *changes v2 -> v3* [PATCH v2 3/4] rebased to http://lists.infradead.org/pipermail/linux-mtd/2014-March/052655.html - no change in other patches *changes v1 -> v2* rebased and cleaned on following versions of pending patches (1) [PATCH v8 0/6] mtd: nand: omap: optimized chip->ecc.correct() for H/W ECC schemes http://lists.infradead.org/pipermail/linux-mtd/2014-February/052092.html (2) [PATCH v6 0/4] mtd: nand: omap: optimize chip->ecc.calculate() for H/W ECC schemes http://lists.infradead.org/pipermail/linux-mtd/2014-February/052272.html (3) [PATCH v5 0/4] mtd: nand: omap: optimize chip->ecc.hwctl() for H/W ECC schemes http://lists.infradead.org/pipermail/linux-mtd/2014-March/052327.html (4) [PATCH v6 0/4] mtd: devices: elm: add checks ELM H/W constrains, driver code cleanup http://lists.infradead.org/pipermail/linux-mtd/2014-March/052455.html Tested on Beaglebone-LT(white) NAND cape having NAND Device with bus-width=16, block-size=256k, page-size=4k, oob-size=224 *original v1* http://lists.infradead.org/pipermail/linux-mtd/2013-July/047562.html With increase in NAND flash densities and shrinking of technology NAND flash has become more suspectible to multiple bit-flips. Thus stronger ECC schemes are required for detecting and correcting multiple simultaneous bit-flips in same NAND page. But stronger ECC schemes have large ECC syndrome which require more space in OOB/Spare. This patch add support for BCH16 ecc-scheme on OMAP NAND driver: (a) BCH16 ecc-scheme can correct 16 bit-flips per 512Bytes of data. (b) BCH16 ecc-scheme generates 26-bytes of ECC syndrome / 512B. Due to (b) this scheme can only be used with NAND devices which have enough OOB to satisfy following equation: OOBsize per page >= 26 * (page-size / 512) Pekon Gupta (4): mtd: nand: omap: add support for BCH16_ECC - GPMC driver updates mtd: nand: omap: add support for BCH16_ECC - ELM driver updates mtd: nand: omap: add support for BCH16_ECC - NAND driver updates mtd: nand: omap: Documentation: How to select correct ECC scheme for your device ? .../devicetree/bindings/mtd/gpmc-nand.txt | 39 +++++++++ arch/arm/mach-omap2/gpmc.c | 15 ++++ drivers/mtd/devices/elm.c | 42 ++++++++++ drivers/mtd/nand/omap2.c | 94 ++++++++++++++++++++++ include/linux/platform_data/elm.h | 3 +- include/linux/platform_data/mtd-nand-omap2.h | 5 ++ 6 files changed, 197 insertions(+), 1 deletion(-) -- 1.8.5.1.163.gd7aced9