243 lines
6.8 KiB
C
243 lines
6.8 KiB
C
/*
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* drivers/mtd/nand/nomadik_nand.c
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*
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* Overview:
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* Driver for on-board NAND flash on Nomadik Platforms
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*
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* Copyright (C) 2007 STMicroelectronics Pvt. Ltd.
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* Author: Sachin Verma <sachin.verma@st.com>
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*
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* Copyright (C) 2009 Alessandro Rubini
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <common.h>
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#include <driver.h>
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#include <malloc.h>
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#include <init.h>
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#include <linux/types.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/nand.h>
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#include <io.h>
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#include <mach/nand.h>
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#include <mach/fsmc.h>
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#include <errno.h>
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struct nomadik_nand_host {
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struct mtd_info mtd;
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struct nand_chip nand;
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void __iomem *cmd_va;
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void __iomem *addr_va;
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struct nand_bbt_descr *bbt_desc;
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};
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static inline int parity(int b) /* uses low 8 bits: returns 0 or all-1 */
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{
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b = b ^ (b >> 4);
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b = b ^ (b >> 2);
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return (b ^ (b >> 1)) & 1
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? ~0 : 0;
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}
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/*
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* This is the ECC routine used in hardware, according to the manual.
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* HW claims to make the calculation but not the correction. However,
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* I haven't managed to get the desired data out of it; so do it in sw.
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* There is problably some errata involved, but currently miss the info.
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*/
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static int nomadik_ecc512_calc(struct mtd_info *mtd, const u_char *data,
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u_char *ecc)
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{
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int gpar = 0;
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int i, val, par;
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int pbits = 0; /* P8, P16, ... P2048 */
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int pprime = 0; /* P8', P16', ... P2048' */
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int lowbits; /* P1, P2, P4 and primes */
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for (i = 0; i < 512; i++) {
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par = parity((val = data[i]));
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gpar ^= val;
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pbits ^= (i & par);
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}
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/*
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* Ok, now gpar is global parity (xor of all bytes)
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* pbits are all the parity bits (non-prime ones)
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*/
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par = parity(gpar);
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pprime = pbits ^ par;
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/* Put low bits in the right position for ecc[2] (bits 7..2) */
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lowbits = 0
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| (parity(gpar & 0xf0) & 0x80) /* P4 */
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| (parity(gpar & 0x0f) & 0x40) /* P4' */
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| (parity(gpar & 0xcc) & 0x20) /* P2 */
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| (parity(gpar & 0x33) & 0x10) /* P2' */
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| (parity(gpar & 0xaa) & 0x08) /* P1 */
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| (parity(gpar & 0x55) & 0x04); /* P1' */
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ecc[2] = ~(lowbits | ((pbits & 0x100) >> 7) | ((pprime & 0x100) >> 8));
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/* now intermix bits for ecc[1] (P1024..P128') and ecc[0] (P64..P8') */
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ecc[1] = ~( (pbits & 0x80) >> 0 | ((pprime & 0x80) >> 1)
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| ((pbits & 0x40) >> 1) | ((pprime & 0x40) >> 2)
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| ((pbits & 0x20) >> 2) | ((pprime & 0x20) >> 3)
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| ((pbits & 0x10) >> 3) | ((pprime & 0x10) >> 4));
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ecc[0] = ~( (pbits & 0x8) << 4 | ((pprime & 0x8) << 3)
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| ((pbits & 0x4) << 3) | ((pprime & 0x4) << 2)
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| ((pbits & 0x2) << 2) | ((pprime & 0x2) << 1)
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| ((pbits & 0x1) << 1) | ((pprime & 0x1) << 0));
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return 0;
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}
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static int nomadik_ecc512_correct(struct mtd_info *mtd, uint8_t *dat,
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uint8_t *r_ecc, uint8_t *c_ecc)
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{
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struct nand_chip *chip = mtd->priv;
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uint32_t r, c, d, diff; /*read, calculated, xor of them */
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if (!memcmp(r_ecc, c_ecc, chip->ecc.bytes))
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return 0;
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/* Reorder the bytes into ascending-order 24 bits -- see manual */
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r = r_ecc[2] << 22 | r_ecc[1] << 14 | r_ecc[0] << 6 | r_ecc[2] >> 2;
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c = c_ecc[2] << 22 | c_ecc[1] << 14 | c_ecc[0] << 6 | c_ecc[2] >> 2;
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diff = (r ^ c) & ((1 << 24) - 1); /* use 24 bits only */
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/* If 12 bits are different, one per pair, it's correctable */
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if (((diff | (diff>>1)) & 0x555555) == 0x555555) {
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int bit = ((diff & 2) >> 1)
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| ((diff & 0x8) >> 2) | ((diff & 0x20) >> 3);
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int byte;
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d = diff >> 6; /* remove bit-order info */
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byte = ((d & 2) >> 1)
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| ((d & 0x8) >> 2) | ((d & 0x20) >> 3)
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| ((d & 0x80) >> 4) | ((d & 0x200) >> 5)
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| ((d & 0x800) >> 6) | ((d & 0x2000) >> 7)
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| ((d & 0x8000) >> 8) | ((d & 0x20000) >> 9);
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/* correct the single bit */
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dat[byte] ^= 1 << bit;
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return 0;
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}
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/* If 1 bit only differs, it's one bit error in ECC, ignore */
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if ((diff ^ (1 << (ffs(diff) - 1))) == 0)
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return 0;
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/* Otherwise, uncorrectable */
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return -1;
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}
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static struct nand_ecclayout nomadik_ecc_layout = {
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.eccbytes = 3 * 4,
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.eccpos = { /* each subpage has 16 bytes: pos 2,3,4 hosts ECC */
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0x02, 0x03, 0x04,
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0x12, 0x13, 0x14,
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0x22, 0x23, 0x24,
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0x32, 0x33, 0x34},
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/* let's keep bytes 5,6,7 for us, just in case we change ECC algo */
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.oobfree = { {0x08, 0x08}, {0x18, 0x08}, {0x28, 0x08}, {0x38, 0x08} },
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};
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static void nomadik_ecc_control(struct mtd_info *mtd, int mode)
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{
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/* No need to enable hw ecc, it's on by default */
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}
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static void nomadik_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
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{
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struct nand_chip *nand = mtd->priv;
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struct nomadik_nand_host *host = nand->priv;
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if (cmd == NAND_CMD_NONE)
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return;
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if (ctrl & NAND_CLE)
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writeb(cmd, host->cmd_va);
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else
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writeb(cmd, host->addr_va);
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}
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static int nomadik_nand_probe(struct device_d *dev)
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{
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struct nomadik_nand_platform_data *pdata = dev->platform_data;
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struct nomadik_nand_host *host;
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struct mtd_info *mtd;
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struct nand_chip *nand;
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int ret = 0;
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/* Allocate memory for the device structure (and zero it) */
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host = kzalloc(sizeof(struct nomadik_nand_host), GFP_KERNEL);
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if (!host) {
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dev_err(dev, "Failed to allocate device structure.\n");
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return -ENOMEM;
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}
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/* Call the client's init function, if any */
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if (pdata->init && (ret = pdata->init()) < 0) {
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dev_err(dev, "Init function failed\n");
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goto err;
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}
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host->cmd_va = dev_request_mem_region_by_name(dev, "nand_cmd");
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host->addr_va = dev_request_mem_region_by_name(dev, "nand_addr");
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/* Link all private pointers */
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mtd = &host->mtd;
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nand = &host->nand;
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mtd->priv = nand;
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nand->priv = host;
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mtd->parent = dev;
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nand->IO_ADDR_W = nand->IO_ADDR_R = dev_request_mem_region_by_name(dev, "nand_data");
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nand->cmd_ctrl = nomadik_cmd_ctrl;
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nand->ecc.mode = NAND_ECC_HW;
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nand->ecc.layout = &nomadik_ecc_layout;
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nand->ecc.calculate = nomadik_ecc512_calc;
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nand->ecc.correct = nomadik_ecc512_correct;
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nand->ecc.hwctl = nomadik_ecc_control;
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nand->ecc.size = 512;
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nand->ecc.bytes = 3;
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nand->ecc.strength = 1;
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nand->options = pdata->options;
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/*
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* Scan to find existance of the device
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*/
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if (nand_scan(&host->mtd, 1)) {
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ret = -ENXIO;
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goto err;
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}
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pr_info("Registering %s as whole device\n", mtd->name);
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add_mtd_nand_device(mtd, "nand");
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return 0;
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err:
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kfree(host);
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return ret;
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}
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static struct driver_d nomadik_nand_driver = {
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.probe = nomadik_nand_probe,
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.name = "nomadik_nand",
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};
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device_platform_driver(nomadik_nand_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("ST Microelectronics (sachin.verma@st.com)");
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MODULE_DESCRIPTION("NAND driver for Nomadik Platform");
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