diff options
Diffstat (limited to 'drivers/mtd')
| -rw-r--r-- | drivers/mtd/nand/atmel_nand.c | 265 | ||||
| -rw-r--r-- | drivers/mtd/nand/atmel_nand_ecc.h | 36 |
2 files changed, 301 insertions, 0 deletions
diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c index 40002be..d5eb54a 100644 --- a/drivers/mtd/nand/atmel_nand.c +++ b/drivers/mtd/nand/atmel_nand.c @@ -31,6 +31,209 @@ #include <nand.h> +#ifdef CONFIG_ATMEL_NAND_HWECC + +/* Register access macros */ +#define ecc_readl(add, reg) \ + readl(AT91_BASE_SYS + add + ATMEL_ECC_##reg) +#define ecc_writel(add, reg, value) \ + writel((value), AT91_BASE_SYS + add + ATMEL_ECC_##reg) + +#include "atmel_nand_ecc.h" /* Hardware ECC registers */ + +/* oob layout for large page size + * bad block info is on bytes 0 and 1 + * the bytes have to be consecutives to avoid + * several NAND_CMD_RNDOUT during read + */ +static struct nand_ecclayout atmel_oobinfo_large = { + .eccbytes = 4, + .eccpos = {60, 61, 62, 63}, + .oobfree = { + {2, 58} + }, +}; + +/* oob layout for small page size + * bad block info is on bytes 4 and 5 + * the bytes have to be consecutives to avoid + * several NAND_CMD_RNDOUT during read + */ +static struct nand_ecclayout atmel_oobinfo_small = { + .eccbytes = 4, + .eccpos = {0, 1, 2, 3}, + .oobfree = { + {6, 10} + }, +}; + +/* + * Calculate HW ECC + * + * function called after a write + * + * mtd: MTD block structure + * dat: raw data (unused) + * ecc_code: buffer for ECC + */ +static int atmel_nand_calculate(struct mtd_info *mtd, + const u_char *dat, unsigned char *ecc_code) +{ + struct nand_chip *nand_chip = mtd->priv; + unsigned int ecc_value; + + /* get the first 2 ECC bytes */ + ecc_value = ecc_readl(CONFIG_SYS_NAND_ECC_BASE, PR); + + ecc_code[0] = ecc_value & 0xFF; + ecc_code[1] = (ecc_value >> 8) & 0xFF; + + /* get the last 2 ECC bytes */ + ecc_value = ecc_readl(CONFIG_SYS_NAND_ECC_BASE, NPR) & ATMEL_ECC_NPARITY; + + ecc_code[2] = ecc_value & 0xFF; + ecc_code[3] = (ecc_value >> 8) & 0xFF; + + return 0; +} + +/* + * HW ECC read page function + * + * mtd: mtd info structure + * chip: nand chip info structure + * buf: buffer to store read data + */ +static int atmel_nand_read_page(struct mtd_info *mtd, + struct nand_chip *chip, uint8_t *buf, int page) +{ + int eccsize = chip->ecc.size; + int eccbytes = chip->ecc.bytes; + uint32_t *eccpos = chip->ecc.layout->eccpos; + uint8_t *p = buf; + uint8_t *oob = chip->oob_poi; + uint8_t *ecc_pos; + int stat; + + /* read the page */ + chip->read_buf(mtd, p, eccsize); + + /* move to ECC position if needed */ + if (eccpos[0] != 0) { + /* This only works on large pages + * because the ECC controller waits for + * NAND_CMD_RNDOUTSTART after the + * NAND_CMD_RNDOUT. + * anyway, for small pages, the eccpos[0] == 0 + */ + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, + mtd->writesize + eccpos[0], -1); + } + + /* the ECC controller needs to read the ECC just after the data */ + ecc_pos = oob + eccpos[0]; + chip->read_buf(mtd, ecc_pos, eccbytes); + + /* check if there's an error */ + stat = chip->ecc.correct(mtd, p, oob, NULL); + + if (stat < 0) + mtd->ecc_stats.failed++; + else + mtd->ecc_stats.corrected += stat; + + /* get back to oob start (end of page) */ + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize, -1); + + /* read the oob */ + chip->read_buf(mtd, oob, mtd->oobsize); + + return 0; +} + +/* + * HW ECC Correction + * + * function called after a read + * + * mtd: MTD block structure + * dat: raw data read from the chip + * read_ecc: ECC from the chip (unused) + * isnull: unused + * + * Detect and correct a 1 bit error for a page + */ +static int atmel_nand_correct(struct mtd_info *mtd, u_char *dat, + u_char *read_ecc, u_char *isnull) +{ + struct nand_chip *nand_chip = mtd->priv; + unsigned int ecc_status, ecc_parity, ecc_mode; + unsigned int ecc_word, ecc_bit; + + /* get the status from the Status Register */ + ecc_status = ecc_readl(CONFIG_SYS_NAND_ECC_BASE, SR); + + /* if there's no error */ + if (likely(!(ecc_status & ATMEL_ECC_RECERR))) + return 0; + + /* get error bit offset (4 bits) */ + ecc_bit = ecc_readl(CONFIG_SYS_NAND_ECC_BASE, PR) & ATMEL_ECC_BITADDR; + /* get word address (12 bits) */ + ecc_word = ecc_readl(CONFIG_SYS_NAND_ECC_BASE, PR) & ATMEL_ECC_WORDADDR; + ecc_word >>= 4; + + /* if there are multiple errors */ + if (ecc_status & ATMEL_ECC_MULERR) { + /* check if it is a freshly erased block + * (filled with 0xff) */ + if ((ecc_bit == ATMEL_ECC_BITADDR) + && (ecc_word == (ATMEL_ECC_WORDADDR >> 4))) { + /* the block has just been erased, return OK */ + return 0; + } + /* it doesn't seems to be a freshly + * erased block. + * We can't correct so many errors */ + printk(KERN_WARNING "atmel_nand : multiple errors detected." + " Unable to correct.\n"); + return -EIO; + } + + /* if there's a single bit error : we can correct it */ + if (ecc_status & ATMEL_ECC_ECCERR) { + /* there's nothing much to do here. + * the bit error is on the ECC itself. + */ + printk(KERN_WARNING "atmel_nand : one bit error on ECC code." + " Nothing to correct\n"); + return 0; + } + + printk(KERN_WARNING "atmel_nand : one bit error on data." + " (word offset in the page :" + " 0x%x bit offset : 0x%x)\n", + ecc_word, ecc_bit); + /* correct the error */ + if (nand_chip->options & NAND_BUSWIDTH_16) { + /* 16 bits words */ + ((unsigned short *) dat)[ecc_word] ^= (1 << ecc_bit); + } else { + /* 8 bits words */ + dat[ecc_word] ^= (1 << ecc_bit); + } + printk(KERN_WARNING "atmel_nand : error corrected\n"); + return 1; +} + +/* + * Enable HW ECC : unused on most chips + */ +static void atmel_nand_hwctl(struct mtd_info *mtd, int mode) +{ +} +#endif + static void at91_nand_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl) { @@ -64,6 +267,11 @@ static int at91_nand_ready(struct mtd_info *mtd) int board_nand_init(struct nand_chip *nand) { +#ifdef CONFIG_ATMEL_NAND_HWECC + static int chip_nr = 0; + struct mtd_info *mtd; +#endif + nand->ecc.mode = NAND_ECC_SOFT; #ifdef CONFIG_SYS_NAND_DBW_16 nand->options = NAND_BUSWIDTH_16; @@ -74,5 +282,62 @@ int board_nand_init(struct nand_chip *nand) #endif nand->chip_delay = 20; +#ifdef CONFIG_ATMEL_NAND_HWECC + nand->ecc.mode = NAND_ECC_HW; + nand->ecc.calculate = atmel_nand_calculate; + nand->ecc.correct = atmel_nand_correct; + nand->ecc.hwctl = atmel_nand_hwctl; + nand->ecc.read_page = atmel_nand_read_page; + nand->ecc.bytes = 4; +#endif + +#ifdef CONFIG_ATMEL_NAND_HWECC + mtd = &nand_info[chip_nr++]; + mtd->priv = nand; + + /* Detect NAND chips */ + if (nand_scan_ident(mtd, 1)) { + printk(KERN_WARNING "NAND Flash not found !\n"); + return -ENXIO; + } + + if (nand->ecc.mode == NAND_ECC_HW) { + /* ECC is calculated for the whole page (1 step) */ + nand->ecc.size = mtd->writesize; + + /* set ECC page size and oob layout */ + switch (mtd->writesize) { + case 512: + nand->ecc.layout = &atmel_oobinfo_small; + ecc_writel(CONFIG_SYS_NAND_ECC_BASE, MR, ATMEL_ECC_PAGESIZE_528); + break; + case 1024: + nand->ecc.layout = &atmel_oobinfo_large; + ecc_writel(CONFIG_SYS_NAND_ECC_BASE, MR, ATMEL_ECC_PAGESIZE_1056); + break; + case 2048: + nand->ecc.layout = &atmel_oobinfo_large; + ecc_writel(CONFIG_SYS_NAND_ECC_BASE, MR, ATMEL_ECC_PAGESIZE_2112); + break; + case 4096: + nand->ecc.layout = &atmel_oobinfo_large; + ecc_writel(CONFIG_SYS_NAND_ECC_BASE, MR, ATMEL_ECC_PAGESIZE_4224); + break; + default: + /* page size not handled by HW ECC */ + /* switching back to soft ECC */ + nand->ecc.mode = NAND_ECC_SOFT; + nand->ecc.calculate = NULL; + nand->ecc.correct = NULL; + nand->ecc.hwctl = NULL; + nand->ecc.read_page = NULL; + nand->ecc.postpad = 0; + nand->ecc.prepad = 0; + nand->ecc.bytes = 0; + break; + } + } +#endif + return 0; } diff --git a/drivers/mtd/nand/atmel_nand_ecc.h b/drivers/mtd/nand/atmel_nand_ecc.h new file mode 100644 index 0000000..1ee7f99 --- /dev/null +++ b/drivers/mtd/nand/atmel_nand_ecc.h @@ -0,0 +1,36 @@ +/* + * Error Corrected Code Controller (ECC) - System peripherals regsters. + * Based on AT91SAM9260 datasheet revision B. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + */ + +#ifndef ATMEL_NAND_ECC_H +#define ATMEL_NAND_ECC_H + +#define ATMEL_ECC_CR 0x00 /* Control register */ +#define ATMEL_ECC_RST (1 << 0) /* Reset parity */ + +#define ATMEL_ECC_MR 0x04 /* Mode register */ +#define ATMEL_ECC_PAGESIZE (3 << 0) /* Page Size */ +#define ATMEL_ECC_PAGESIZE_528 (0) +#define ATMEL_ECC_PAGESIZE_1056 (1) +#define ATMEL_ECC_PAGESIZE_2112 (2) +#define ATMEL_ECC_PAGESIZE_4224 (3) + +#define ATMEL_ECC_SR 0x08 /* Status register */ +#define ATMEL_ECC_RECERR (1 << 0) /* Recoverable Error */ +#define ATMEL_ECC_ECCERR (1 << 1) /* ECC Single Bit Error */ +#define ATMEL_ECC_MULERR (1 << 2) /* Multiple Errors */ + +#define ATMEL_ECC_PR 0x0c /* Parity register */ +#define ATMEL_ECC_BITADDR (0xf << 0) /* Bit Error Address */ +#define ATMEL_ECC_WORDADDR (0xfff << 4) /* Word Error Address */ + +#define ATMEL_ECC_NPR 0x10 /* NParity register */ +#define ATMEL_ECC_NPARITY (0xffff << 0) /* NParity */ + +#endif |