cpu/arm920t/s3c24x0/nand_read.c

   1 /*
   2  * nand_read.c: Simple NAND read functions for booting from NAND
   3  *
   4  * This is used by cpu/arm920/start.S assembler code,
   5  * and the board-specific linker script must make sure this
   6  * file is linked within the first 4kB of NAND flash.
   7  *
   8  * Taken from GPLv2 licensed vivi bootloader,
   9  * Copyright (C) 2002 MIZI Research, Inc.
  10  *
  11  * Author: Hwang, Chideok <hwang@mizi.com>
  12  * Date  : $Date: 2004/02/04 10:37:37 $
  13  *
  14  * u-boot integration and bad-block skipping (C) 2006 by OpenMoko, Inc.
  15  * Author: Harald Welte <laforge@openmoko.org>
  16  */
  17
  18 #include <common.h>
  19 #include <linux/mtd/nand.h>
  20
  21 #ifdef CONFIG_S3C2410_NAND_BOOT
  22
  23 #define __REGb(x)       (*(volatile unsigned char *)(x))
  24 #define __REGw(x)       (*(volatile unsigned short *)(x))
  25 #define __REGi(x)       (*(volatile unsigned int *)(x))
  26 #define NF_BASE         0x4e000000
  27 #if defined(CONFIG_S3C2410)
  28 #define NFCONF          __REGi(NF_BASE + 0x0)
  29 #define NFCMD           __REGb(NF_BASE + 0x4)
  30 #define NFADDR          __REGb(NF_BASE + 0x8)
  31 #define NFDATA          __REGb(NF_BASE + 0xc)
  32 #define NFSTAT          __REGb(NF_BASE + 0x10)
  33 #define NFSTAT_BUSY     1
  34 #define nand_select()   (NFCONF &= ~0x800)
  35 #define nand_deselect() (NFCONF |= 0x800)
  36 #define nand_clear_RnB()        do {} while (0)
  37 #elif defined(CONFIG_S3C2440) || defined(CONFIG_S3C2442)
  38 #define NFCONF          __REGi(NF_BASE + 0x0)
  39 #define NFCONT          __REGi(NF_BASE + 0x4)
  40 #define NFCMD           __REGb(NF_BASE + 0x8)
  41 #define NFADDR          __REGb(NF_BASE + 0xc)
  42 #define NFDATA          __REGb(NF_BASE + 0x10)
  43 #define NFDATA16        __REGw(NF_BASE + 0x10)
  44 #define NFSTAT          __REGb(NF_BASE + 0x20)
  45 #define NFSTAT_BUSY     1
  46 #define nand_select()   (NFCONT &= ~(1 << 1))
  47 #define nand_deselect() (NFCONT |= (1 << 1))
  48 #define nand_clear_RnB()        (NFSTAT |= (1 << 2))
  49 #endif
  50
  51 static inline void nand_wait(void)
  52 {
  53         int i;
  54
  55         while (!(NFSTAT & NFSTAT_BUSY))
  56                 for (i=0; i<10; i++);
  57 }
  58
  59 #if defined(CONFIG_S3C2410) || defined(CONFIG_MINI2440)
  60 /* configuration for 2410 with 512byte sized flash */
  61 #define NAND_PAGE_SIZE          512
  62 #define BAD_BLOCK_OFFSET        5
  63 #define NAND_BLOCK_MASK         (NAND_PAGE_SIZE - 1)
  64 #define NAND_BLOCK_SIZE         0x4000
  65 #else
  66 /* configuration for 2440 with 2048byte sized flash */
  67 #define NAND_5_ADDR_CYCLE
  68 #define NAND_PAGE_SIZE          2048
  69 #define BAD_BLOCK_OFFSET        NAND_PAGE_SIZE
  70 #define NAND_BLOCK_MASK         (NAND_PAGE_SIZE - 1)
  71 #define NAND_BLOCK_SIZE         (NAND_PAGE_SIZE * 64)
  72 #endif
  73
  74 /* compile time failure in case of an invalid configuration */
  75 #if defined(CONFIG_S3C2410) && (NAND_PAGE_SIZE != 512)
  76 #error "S3C2410 does not support nand page size != 512"
  77 #endif
  78
  79 static int is_bad_block(unsigned long i)
  80 {
  81         unsigned char data;
  82         unsigned long page_num;
  83
  84         nand_clear_RnB();
  85 #if (NAND_PAGE_SIZE == 512)
  86         NFCMD = NAND_CMD_READOOB; /* 0x50 */
  87         NFADDR = BAD_BLOCK_OFFSET & 0xf;
  88         NFADDR = (i >> 9) & 0xff;
  89         NFADDR = (i >> 17) & 0xff;
  90         NFADDR = (i >> 25) & 0xff;
  91 #elif (NAND_PAGE_SIZE == 2048)
  92         page_num = i >> 11; /* addr / 2048 */
  93         NFCMD = NAND_CMD_READ0;
  94         NFADDR = BAD_BLOCK_OFFSET & 0xff;
  95         NFADDR = (BAD_BLOCK_OFFSET >> 8) & 0xff;
  96         NFADDR = page_num & 0xff;
  97         NFADDR = (page_num >> 8) & 0xff;
  98         NFADDR = (page_num >> 16) & 0xff;
  99         NFCMD = NAND_CMD_READSTART;
 100 #endif
 101         nand_wait();
 102         data = (NFDATA & 0xff);
 103         if (data != 0xff)
 104                 return 1;
 105
 106         return 0;
 107 }
 108
 109 static int nand_read_page_ll(unsigned char *buf, unsigned long addr)
 110 {
 111         unsigned short *ptr16 = (unsigned short *)buf;
 112         unsigned int i, page_num;
 113
 114         nand_clear_RnB();
 115
 116         NFCMD = NAND_CMD_READ0;
 117
 118 #if (NAND_PAGE_SIZE == 512)
 119         /* Write Address */
 120         NFADDR = addr & 0xff;
 121         NFADDR = (addr >> 9) & 0xff;
 122         NFADDR = (addr >> 17) & 0xff;
 123         NFADDR = (addr >> 25) & 0xff;
 124 #elif (NAND_PAGE_SIZE == 2048)
 125         page_num = addr >> 11; /* addr / 2048 */
 126         /* Write Address */
 127         NFADDR = 0;
 128         NFADDR = 0;
 129         NFADDR = page_num & 0xff;
 130         NFADDR = (page_num >> 8) & 0xff;
 131         NFADDR = (page_num >> 16) & 0xff;
 132         NFCMD = NAND_CMD_READSTART;
 133 #else
 134 #error "unsupported nand page size"
 135 #endif
 136         nand_wait();
 137
 138 #if defined(CONFIG_S3C2410)
 139         for (i = 0; i < NAND_PAGE_SIZE; i++) {
 140                 *buf = (NFDATA & 0xff);
 141                 buf++;
 142         }
 143 #elif defined(CONFIG_S3C2440) || defined(CONFIG_S3C2442)
 144         for (i = 0; i < NAND_PAGE_SIZE/2; i++) {
 145                 *ptr16 = NFDATA16;
 146                 ptr16++;
 147         }
 148 #endif
 149
 150         return NAND_PAGE_SIZE;
 151 }
 152
 153 /* low level nand read function */
 154 int nand_read_ll(unsigned char *buf, unsigned long start_addr, int size)
 155 {
 156         int i, j;
 157
 158         if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK))
 159                 return -1;      /* invalid alignment */
 160
 161         /* chip Enable */
 162         nand_select();
 163         nand_clear_RnB();
 164         for (i=0; i<10; i++);
 165
 166         for (i=start_addr; i < (start_addr + size);) {
 167 #ifdef CONFIG_S3C2410_NAND_SKIP_BAD
 168                 if (i % NAND_BLOCK_SIZE == 0) {
 169                         if (is_bad_block(i) ||
 170                             is_bad_block(i + NAND_PAGE_SIZE)) {
 171                                 /* Bad block */
 172                                 i += NAND_BLOCK_SIZE;
 173                                 size += NAND_BLOCK_SIZE;
 174                                 continue;
 175                         }
 176                 }
 177 #endif
 178                 j = nand_read_page_ll(buf, i);
 179                 i += j;
 180                 buf += j;
 181         }
 182
 183         /* chip Disable */
 184         nand_deselect();
 185
 186         return 0;
 187 }
 188
 189 #endif /* CONFIG_S3C2410_NAND_BOOT */