diff options
Diffstat (limited to 'drivers/mtd/nand/nomadik.c')
| -rw-r--r-- | drivers/mtd/nand/nomadik.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/drivers/mtd/nand/nomadik.c b/drivers/mtd/nand/nomadik.c new file mode 100644 index 0000000..08944d1 --- /dev/null +++ b/drivers/mtd/nand/nomadik.c @@ -0,0 +1,221 @@ +/* + * (C) Copyright 2007 STMicroelectronics, <www.st.com> + * (C) Copyright 2009 Alessandro Rubini <rubini@unipv.it> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> +#include <nand.h> +#include <asm/io.h> + +static inline int parity(int b) /* b is really a byte; returns 0 or ~0 */ +{ + __asm__ __volatile__( + "eor %0, %0, %0, lsr #4\n\t" + "eor %0, %0, %0, lsr #2\n\t" + "eor %0, %0, %0, lsr #1\n\t" + "ands %0, %0, #1\n\t" + "subne %0, %0, #2\t" + : "=r" (b) : "0" (b)); + return b; +} + +/* + * This is the ECC routine used in hardware, according to the manual. + * HW claims to make the calculation but not the correction; so we must + * recalculate the bytes for a comparison. + */ +static int ecc512(unsigned char *data, unsigned char *ecc) +{ + int gpar = 0; + int i, val, par; + int pbits = 0; /* P8, P16, ... P2048 */ + int pprime = 0; /* P8', P16', ... P2048' */ + int lowbits; /* P1, P2, P4 and primes */ + + for (i = 0; i < 512; i++) { + par = parity((val = data[i])); + gpar ^= val; + pbits ^= (i & par); + } + /* + * Ok, now gpar is global parity (xor of all bytes) + * pbits are all the parity bits (non-prime ones) + */ + par = parity(gpar); + pprime = pbits ^ par; + /* Put low bits in the right position for ecc[2] (bits 7..2) */ + lowbits = 0 + | (parity(gpar & 0xf0) & 0x80) /* P4 */ + | (parity(gpar & 0x0f) & 0x40) /* P4' */ + | (parity(gpar & 0xcc) & 0x20) /* P2 */ + | (parity(gpar & 0x33) & 0x10) /* P2' */ + | (parity(gpar & 0xaa) & 0x08) /* P1 */ + | (parity(gpar & 0x55) & 0x04); /* P1' */ + + ecc[2] = ~(lowbits | ((pbits & 0x100) >> 7) | ((pprime & 0x100) >> 8)); + /* now intermix bits for ecc[1] (P1024..P128') and ecc[0] (P64..P8') */ + ecc[1] = ~( (pbits & 0x80) >> 0 | ((pprime & 0x80) >> 1) + | ((pbits & 0x40) >> 1) | ((pprime & 0x40) >> 2) + | ((pbits & 0x20) >> 2) | ((pprime & 0x20) >> 3) + | ((pbits & 0x10) >> 3) | ((pprime & 0x10) >> 4)); + + ecc[0] = ~( (pbits & 0x8) << 4 | ((pprime & 0x8) << 3) + | ((pbits & 0x4) << 3) | ((pprime & 0x4) << 2) + | ((pbits & 0x2) << 2) | ((pprime & 0x2) << 1) + | ((pbits & 0x1) << 1) | ((pprime & 0x1) << 0)); + return 0; +} + +/* This is the method in the chip->ecc field */ +static int nomadik_ecc_calculate(struct mtd_info *mtd, const uint8_t *dat, + uint8_t *ecc_code) +{ + return ecc512(dat, ecc_code); +} + +static int nomadik_ecc_correct(struct mtd_info *mtd, uint8_t *dat, + uint8_t *r_ecc, uint8_t *c_ecc) +{ + struct nand_chip *chip = mtd->priv; + uint32_t r, c, d, diff; /*read, calculated, xor of them */ + + if (!memcmp(r_ecc, c_ecc, chip->ecc.bytes)) + return 0; + + /* Reorder the bytes into ascending-order 24 bits -- see manual */ + r = r_ecc[2] << 22 | r_ecc[1] << 14 | r_ecc[0] << 6 | r_ecc[2] >> 2; + c = c_ecc[2] << 22 | c_ecc[1] << 14 | c_ecc[0] << 6 | c_ecc[2] >> 2; + diff = (r ^ c) & ((1<<24)-1); /* use 24 bits only */ + + /* If 12 bits are different, one per pair, it's correctable */ + if (((diff | (diff>>1)) & 0x555555) == 0x555555) { + int bit = ((diff & 2) >> 1) + | ((diff & 0x8) >> 2) | ((diff & 0x20) >> 3); + int byte; + + d = diff >> 6; /* remove bit-order info */ + byte = ((d & 2) >> 1) + | ((d & 0x8) >> 2) | ((d & 0x20) >> 3) + | ((d & 0x80) >> 4) | ((d & 0x200) >> 5) + | ((d & 0x800) >> 6) | ((d & 0x2000) >> 7) + | ((d & 0x8000) >> 8) | ((d & 0x20000) >> 9); + /* correct the single bit */ + dat[byte] ^= 1<<bit; + return 0; + } + /* If 1 bit only differs, it's one bit error in ECC, ignore */ + if ((diff ^ (1 << (ffs(diff) - 1))) == 0) + return 0; + /* Otherwise, uncorrectable */ + return -1; +} + +static void nomadik_ecc_hwctl(struct mtd_info *mtd, int mode) +{ /* mandatory in the structure but not used here */ } + + +/* This is the layout used by older installations, we keep compatible */ +struct nand_ecclayout nomadik_ecc_layout = { + .eccbytes = 3 * 4, + .eccpos = { /* each subpage has 16 bytes: pos 2,3,4 hosts ECC */ + 0x02, 0x03, 0x04, + 0x12, 0x13, 0x14, + 0x22, 0x23, 0x24, + 0x32, 0x33, 0x34}, + .oobfree = { {0x08, 0x08}, {0x18, 0x08}, {0x28, 0x08}, {0x38, 0x08} }, +}; + +#define MASK_ALE (1 << 24) /* our ALE is AD21 */ +#define MASK_CLE (1 << 23) /* our CLE is AD22 */ + +/* This is copied from the AT91SAM9 devices (Stelian Pop, Lead Tech Design) */ +static void nomadik_nand_hwcontrol(struct mtd_info *mtd, + int cmd, unsigned int ctrl) +{ + struct nand_chip *this = mtd->priv; + u32 pcr0 = readl(REG_FSMC_PCR0); + + if (ctrl & NAND_CTRL_CHANGE) { + ulong IO_ADDR_W = (ulong) this->IO_ADDR_W; + IO_ADDR_W &= ~(MASK_ALE | MASK_CLE); + + if (ctrl & NAND_CLE) + IO_ADDR_W |= MASK_CLE; + if (ctrl & NAND_ALE) + IO_ADDR_W |= MASK_ALE; + + if (ctrl & NAND_NCE) + writel(pcr0 | 0x4, REG_FSMC_PCR0); + else + writel(pcr0 & ~0x4, REG_FSMC_PCR0); + + this->IO_ADDR_W = (void *) IO_ADDR_W; + this->IO_ADDR_R = (void *) IO_ADDR_W; + } + + if (cmd != NAND_CMD_NONE) + writeb(cmd, this->IO_ADDR_W); +} + +/* Returns 1 when ready; upper layers timeout at 20ms with timer routines */ +static int nomadik_nand_ready(struct mtd_info *mtd) +{ + return 1; /* The ready bit is handled in hardware */ +} + +/* Copy a buffer 32bits at a time: faster than defualt method which is 8bit */ +static void nomadik_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len) +{ + int i; + struct nand_chip *chip = mtd->priv; + u32 *p = (u32 *) buf; + + len >>= 2; + writel(0, REG_FSMC_ECCR0); + for (i = 0; i < len; i++) + p[i] = readl(chip->IO_ADDR_R); +} + +int board_nand_init(struct nand_chip *chip) +{ + /* Set up the FSMC_PCR0 for nand access*/ + writel(0x0000004a, REG_FSMC_PCR0); + /* Set up FSMC_PMEM0, FSMC_PATT0 with timing data for access */ + writel(0x00020401, REG_FSMC_PMEM0); + writel(0x00020404, REG_FSMC_PATT0); + + chip->options = NAND_COPYBACK | NAND_CACHEPRG | NAND_NO_PADDING; + chip->cmd_ctrl = nomadik_nand_hwcontrol; + chip->dev_ready = nomadik_nand_ready; + /* The chip allows 32bit reads, so avoid the default 8bit copy */ + chip->read_buf = nomadik_nand_read_buf; + + /* ECC: follow the hardware-defined rulse, but do it in sw */ + chip->ecc.mode = NAND_ECC_HW; + chip->ecc.bytes = 3; + chip->ecc.size = 512; + chip->ecc.layout = &nomadik_ecc_layout; + chip->ecc.calculate = nomadik_ecc_calculate; + chip->ecc.hwctl = nomadik_ecc_hwctl; + chip->ecc.correct = nomadik_ecc_correct; + + return 0; +} |