[v3] ARM: OMAP3: gpmc: add BCH ecc api and modes

Message ID	1335442669-13474-1-git-send-email-ivan.djelic@parrot.com
State	Not Applicable
Headers	show Return-Path: <linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org> From: Ivan Djelic <ivan.djelic@parrot.com> 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> 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 <tony@atomide.com>, ivan.djelic@parrot.com, linux-mtd@lists.infradead.org Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-mtd-bounces@lists.infradead.org Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org

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

[v3] ARM: OMAP3: gpmc: add BCH ecc api and modes

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