From patchwork Thu Apr 26 12:17:49 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ivan Djelic X-Patchwork-Id: 155261 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:4978:20e::2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 8DC7FB6EEC for ; Thu, 26 Apr 2012 22:21:25 +1000 (EST) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1SNNfd-00079Z-I4; Thu, 26 Apr 2012 12:19:37 +0000 Received: from mail-wg0-f49.google.com ([74.125.82.49]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1SNNfa-00079L-1e for linux-mtd@lists.infradead.org; Thu, 26 Apr 2012 12:19:35 +0000 Received: by wgbds1 with SMTP id ds1so293983wgb.18 for ; Thu, 26 Apr 2012 05:19:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:x-mailer; bh=l5kuKKlLL6u8D+lXVqP1Z3coHP5fhO9Wrb55YXMrVeg=; b=LnOHE7orwFvy8fZrmm1irLnOlYkNdqs6ayyAn3TE3joayF1HiEXKv0kY3BQv4LNakp 6C+1fG3M1MWVkxqxvwYR19vaKkv8QK0LsWf6RQbJLYdZLe3sS2tmSvnSq9lcjhSa8P/c KnG1mQdf3UGkudJmbJJsRmNKyUCwfk+t0Iv/UQuZJVrpFyPljR2NtUIRZZ1CIITLBGpT nBKVPrIQ27h7qBpoBRzFdqosn6NmC5509D95OVMEy1eKyIL7PhTYtp7bhi63tG5fOgiA Az/MFiNLK5ZqAXzMKu6I4guHSrFnL+oRUv+akvlY8s/uQ+yVALSB3P1hNGKbqzH3wI5S R1sw== Received: by 10.216.134.41 with SMTP id r41mr4177752wei.13.1335442771053; Thu, 26 Apr 2012 05:19:31 -0700 (PDT) Received: from aigle.Parrot.Biz (102.213-31-46.rdns.acropolistelecom.net. [46.31.213.102]) by mx.google.com with ESMTPS id b3sm44415399wib.4.2012.04.26.05.19.27 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 26 Apr 2012 05:19:30 -0700 (PDT) From: Ivan Djelic To: linux-omap@vger.kernel.org Subject: [PATCH v3] ARM: OMAP3: gpmc: add BCH ecc api and modes Date: Thu, 26 Apr 2012 14:17:49 +0200 Message-Id: <1335442669-13474-1-git-send-email-ivan.djelic@parrot.com> X-Mailer: git-send-email 1.7.10 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (ivantchek[at]gmail.com) -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [74.125.82.49 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature Cc: Tony Lindgren , ivan.djelic@parrot.com, linux-mtd@lists.infradead.org X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-mtd-bounces@lists.infradead.org Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org Hello, Here is version 3 of this patch after review from Tony Lindgren. This version adds a separate initialization function mostly to check CPU compatibility. This check cannot be done in gpmc_enable_hwecc_bch() (which is meant to be called from mtd function ecc.hwctl) because ecc.hwctl is not called before the first NAND read access, and it cannot return an error status. Acked-by: Tony Lindgren --- Ivan This patch adds a simple BCH ecc computation api, similar to the existing Hamming ecc api. It is intended to be used by the MTD layer. It implements the following features: - support 4-bit and 8-bit ecc computation - do not protect user bytes in spare area, only data area is protected - ecc for an erased NAND page (0xFFs) is also a sequence of 0xFFs This last feature is obtained by adding a constant polynomial to the hardware computed ecc. It allows to correct bitflips in blank pages and is extremely useful to support filesystems such as UBIFS, which expect erased pages to contain only 0xFFs. This api has been tested on an OMAP3630 board. Signed-off-by: Ivan Djelic --- v3 changelog: added init function to check CPU compatibility v2 changelog: added missing control register configuration arch/arm/mach-omap2/gpmc.c | 184 ++++++++++++++++++++++++++++++++ arch/arm/plat-omap/include/plat/gpmc.h | 11 ++ 2 files changed, 195 insertions(+) diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c index 00d5108..1ca8d7f 100644 --- a/arch/arm/mach-omap2/gpmc.c +++ b/arch/arm/mach-omap2/gpmc.c @@ -49,6 +49,7 @@ #define GPMC_ECC_CONTROL 0x1f8 #define GPMC_ECC_SIZE_CONFIG 0x1fc #define GPMC_ECC1_RESULT 0x200 +#define GPMC_ECC_BCH_RESULT_0 0x240 /* not available on OMAP2 */ #define GPMC_CS0_OFFSET 0x60 #define GPMC_CS_SIZE 0x30 @@ -920,3 +921,186 @@ int gpmc_calculate_ecc(int cs, const u_char *dat, u_char *ecc_code) return 0; } EXPORT_SYMBOL_GPL(gpmc_calculate_ecc); + +#ifdef CONFIG_ARCH_OMAP3 + +/** + * gpmc_init_hwecc_bch - initialize hardware BCH ecc functionality + * @cs: chip select number + * @nsectors: how many 512-byte sectors to process + * @nerrors: how many errors to correct per sector (4 or 8) + * + * This function must be executed before any call to gpmc_enable_hwecc_bch. + */ +int gpmc_init_hwecc_bch(int cs, int nsectors, int nerrors) +{ + /* check if ecc module is in use */ + if (gpmc_ecc_used != -EINVAL) + return -EINVAL; + + /* support only OMAP3 class */ + if (!cpu_is_omap34xx()) { + printk(KERN_ERR "BCH ecc is not supported on this CPU\n"); + return -EINVAL; + } + + /* + * For now, assume 4-bit mode is only supported on OMAP3630 ES1.x, x>=1. + * Other chips may be added if confirmed to work. + */ + if ((nerrors == 4) && + (!cpu_is_omap3630() || (GET_OMAP_REVISION() == 0))) { + printk(KERN_ERR "BCH 4-bit mode is not supported on this CPU\n"); + return -EINVAL; + } + + /* sanity check */ + if (nsectors > 8) { + printk(KERN_ERR "BCH cannot process %d sectors (max is 8)\n", + nsectors); + return -EINVAL; + } + + return 0; +} +EXPORT_SYMBOL_GPL(gpmc_init_hwecc_bch); + +/** + * gpmc_enable_hwecc_bch - enable hardware BCH ecc functionality + * @cs: chip select number + * @mode: read/write mode + * @dev_width: device bus width(1 for x16, 0 for x8) + * @nsectors: how many 512-byte sectors to process + * @nerrors: how many errors to correct per sector (4 or 8) + */ +int gpmc_enable_hwecc_bch(int cs, int mode, int dev_width, int nsectors, + int nerrors) +{ + unsigned int val; + + /* check if ecc module is in use */ + if (gpmc_ecc_used != -EINVAL) + return -EINVAL; + + gpmc_ecc_used = cs; + + /* clear ecc and enable bits */ + gpmc_write_reg(GPMC_ECC_CONTROL, 0x1); + + /* + * When using BCH, sector size is hardcoded to 512 bytes. + * Here we are using wrapping mode 6 both for reading and writing, with: + * size0 = 0 (no additional protected byte in spare area) + * size1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area) + */ + gpmc_write_reg(GPMC_ECC_SIZE_CONFIG, (32 << 22) | (0 << 12)); + + /* BCH configuration */ + val = ((1 << 16) | /* enable BCH */ + (((nerrors == 8) ? 1 : 0) << 12) | /* 8 or 4 bits */ + (0x06 << 8) | /* wrap mode = 6 */ + (dev_width << 7) | /* bus width */ + (((nsectors-1) & 0x7) << 4) | /* number of sectors */ + (cs << 1) | /* ECC CS */ + (0x1)); /* enable ECC */ + + gpmc_write_reg(GPMC_ECC_CONFIG, val); + gpmc_write_reg(GPMC_ECC_CONTROL, 0x101); + return 0; +} +EXPORT_SYMBOL_GPL(gpmc_enable_hwecc_bch); + +/** + * gpmc_calculate_ecc_bch4 - Generate 7 ecc bytes per sector of 512 data bytes + * @cs: chip select number + * @dat: The pointer to data on which ecc is computed + * @ecc: The ecc output buffer + */ +int gpmc_calculate_ecc_bch4(int cs, const u_char *dat, u_char *ecc) +{ + int i; + unsigned long nsectors, reg, val1, val2; + + if (gpmc_ecc_used != cs) + return -EINVAL; + + nsectors = ((gpmc_read_reg(GPMC_ECC_CONFIG) >> 4) & 0x7) + 1; + + for (i = 0; i < nsectors; i++) { + + reg = GPMC_ECC_BCH_RESULT_0 + 16*i; + + /* Read hw-computed remainder */ + val1 = gpmc_read_reg(reg + 0); + val2 = gpmc_read_reg(reg + 4); + + /* + * Add constant polynomial to remainder, in order to get an ecc + * sequence of 0xFFs for a buffer filled with 0xFFs; and + * left-justify the resulting polynomial. + */ + *ecc++ = 0x28 ^ ((val2 >> 12) & 0xFF); + *ecc++ = 0x13 ^ ((val2 >> 4) & 0xFF); + *ecc++ = 0xcc ^ (((val2 & 0xF) << 4)|((val1 >> 28) & 0xF)); + *ecc++ = 0x39 ^ ((val1 >> 20) & 0xFF); + *ecc++ = 0x96 ^ ((val1 >> 12) & 0xFF); + *ecc++ = 0xac ^ ((val1 >> 4) & 0xFF); + *ecc++ = 0x7f ^ ((val1 & 0xF) << 4); + } + + gpmc_ecc_used = -EINVAL; + return 0; +} +EXPORT_SYMBOL_GPL(gpmc_calculate_ecc_bch4); + +/** + * gpmc_calculate_ecc_bch8 - Generate 13 ecc bytes per block of 512 data bytes + * @cs: chip select number + * @dat: The pointer to data on which ecc is computed + * @ecc: The ecc output buffer + */ +int gpmc_calculate_ecc_bch8(int cs, const u_char *dat, u_char *ecc) +{ + int i; + unsigned long nsectors, reg, val1, val2, val3, val4; + + if (gpmc_ecc_used != cs) + return -EINVAL; + + nsectors = ((gpmc_read_reg(GPMC_ECC_CONFIG) >> 4) & 0x7) + 1; + + for (i = 0; i < nsectors; i++) { + + reg = GPMC_ECC_BCH_RESULT_0 + 16*i; + + /* Read hw-computed remainder */ + val1 = gpmc_read_reg(reg + 0); + val2 = gpmc_read_reg(reg + 4); + val3 = gpmc_read_reg(reg + 8); + val4 = gpmc_read_reg(reg + 12); + + /* + * Add constant polynomial to remainder, in order to get an ecc + * sequence of 0xFFs for a buffer filled with 0xFFs. + */ + *ecc++ = 0xef ^ (val4 & 0xFF); + *ecc++ = 0x51 ^ ((val3 >> 24) & 0xFF); + *ecc++ = 0x2e ^ ((val3 >> 16) & 0xFF); + *ecc++ = 0x09 ^ ((val3 >> 8) & 0xFF); + *ecc++ = 0xed ^ (val3 & 0xFF); + *ecc++ = 0x93 ^ ((val2 >> 24) & 0xFF); + *ecc++ = 0x9a ^ ((val2 >> 16) & 0xFF); + *ecc++ = 0xc2 ^ ((val2 >> 8) & 0xFF); + *ecc++ = 0x97 ^ (val2 & 0xFF); + *ecc++ = 0x79 ^ ((val1 >> 24) & 0xFF); + *ecc++ = 0xe5 ^ ((val1 >> 16) & 0xFF); + *ecc++ = 0x24 ^ ((val1 >> 8) & 0xFF); + *ecc++ = 0xb5 ^ (val1 & 0xFF); + } + + gpmc_ecc_used = -EINVAL; + return 0; +} +EXPORT_SYMBOL_GPL(gpmc_calculate_ecc_bch8); + +#endif /* CONFIG_ARCH_OMAP3 */ diff --git a/arch/arm/plat-omap/include/plat/gpmc.h b/arch/arm/plat-omap/include/plat/gpmc.h index 1527929..f37764a 100644 --- a/arch/arm/plat-omap/include/plat/gpmc.h +++ b/arch/arm/plat-omap/include/plat/gpmc.h @@ -92,6 +92,8 @@ enum omap_ecc { OMAP_ECC_HAMMING_CODE_HW, /* gpmc to detect the error */ /* 1-bit ecc: stored at beginning of spare area as romcode */ OMAP_ECC_HAMMING_CODE_HW_ROMCODE, /* gpmc method & romcode layout */ + OMAP_ECC_BCH4_CODE_HW, /* 4-bit BCH ecc code */ + OMAP_ECC_BCH8_CODE_HW, /* 8-bit BCH ecc code */ }; /* @@ -157,4 +159,13 @@ extern int gpmc_nand_write(int cs, int cmd, int wval); int gpmc_enable_hwecc(int cs, int mode, int dev_width, int ecc_size); int gpmc_calculate_ecc(int cs, const u_char *dat, u_char *ecc_code); + +#ifdef CONFIG_ARCH_OMAP3 +int gpmc_init_hwecc_bch(int cs, int nsectors, int nerrors); +int gpmc_enable_hwecc_bch(int cs, int mode, int dev_width, int nsectors, + int nerrors); +int gpmc_calculate_ecc_bch4(int cs, const u_char *dat, u_char *ecc); +int gpmc_calculate_ecc_bch8(int cs, const u_char *dat, u_char *ecc); +#endif /* CONFIG_ARCH_OMAP3 */ + #endif