Mike Dunn | 956b03e | 2013-04-12 11:59:18 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * SPL driver for Diskonchip G4 nand flash |
| 3 | * |
| 4 | * Copyright (C) 2013 Mike Dunn <mikedunn@newsguy.com> |
| 5 | * |
| 6 | * This file is released under the terms of GPL v2 and any later version. |
| 7 | * See the file COPYING in the root directory of the source tree for details. |
| 8 | * |
| 9 | * |
| 10 | * This driver basically mimics the load functionality of a typical IPL (initial |
| 11 | * program loader) resident in the 2k NOR-like region of the docg4 that is |
| 12 | * mapped to the reset vector. It allows the u-boot SPL to continue loading if |
| 13 | * the IPL loads a fixed number of flash blocks that is insufficient to contain |
| 14 | * the entire u-boot image. In this case, a concatenated spl + u-boot image is |
| 15 | * written at the flash offset from which the IPL loads an image, and when the |
| 16 | * IPL jumps to the SPL, the SPL resumes loading where the IPL left off. See |
| 17 | * the palmtreo680 for an example. |
| 18 | * |
| 19 | * This driver assumes that the data was written to the flash using the device's |
| 20 | * "reliable" mode, and also assumes that each 512 byte page is stored |
| 21 | * redundantly in the subsequent page. This storage format is likely to be used |
| 22 | * by all boards that boot from the docg4. The format compensates for the lack |
| 23 | * of ecc in the IPL. |
| 24 | * |
| 25 | * Reliable mode reduces the capacity of a block by half, and the redundant |
| 26 | * pages reduce it by half again. As a result, the normal 256k capacity of a |
| 27 | * block is reduced to 64k for the purposes of the IPL/SPL. |
| 28 | */ |
| 29 | |
| 30 | #include <asm/io.h> |
| 31 | #include <linux/mtd/docg4.h> |
| 32 | |
| 33 | /* forward declarations */ |
| 34 | static inline void write_nop(void __iomem *docptr); |
| 35 | static int poll_status(void __iomem *docptr); |
| 36 | static void write_addr(void __iomem *docptr, uint32_t docg4_addr); |
| 37 | static void address_sequence(unsigned int g4_page, unsigned int g4_index, |
| 38 | void __iomem *docptr); |
| 39 | static int docg4_load_block_reliable(uint32_t flash_offset, void *dest_addr); |
| 40 | |
| 41 | int nand_spl_load_image(uint32_t offs, unsigned int size, void *dst) |
| 42 | { |
| 43 | void *load_addr = dst; |
| 44 | uint32_t flash_offset = offs; |
| 45 | const unsigned int block_count = |
| 46 | (size + DOCG4_BLOCK_CAPACITY_SPL - 1) |
| 47 | / DOCG4_BLOCK_CAPACITY_SPL; |
| 48 | int i; |
| 49 | |
| 50 | for (i = 0; i < block_count; i++) { |
| 51 | int ret = docg4_load_block_reliable(flash_offset, load_addr); |
| 52 | if (ret) |
| 53 | return ret; |
| 54 | load_addr += DOCG4_BLOCK_CAPACITY_SPL; |
| 55 | flash_offset += DOCG4_BLOCK_SIZE; |
| 56 | } |
| 57 | return 0; |
| 58 | } |
| 59 | |
| 60 | static inline void write_nop(void __iomem *docptr) |
| 61 | { |
| 62 | writew(0, docptr + DOC_NOP); |
| 63 | } |
| 64 | |
| 65 | static int poll_status(void __iomem *docptr) |
| 66 | { |
| 67 | /* |
| 68 | * Busy-wait for the FLASHREADY bit to be set in the FLASHCONTROL |
| 69 | * register. Operations known to take a long time (e.g., block erase) |
| 70 | * should sleep for a while before calling this. |
| 71 | */ |
| 72 | |
| 73 | uint8_t flash_status; |
| 74 | |
| 75 | /* hardware quirk requires reading twice initially */ |
| 76 | flash_status = readb(docptr + DOC_FLASHCONTROL); |
| 77 | |
| 78 | do { |
| 79 | flash_status = readb(docptr + DOC_FLASHCONTROL); |
| 80 | } while (!(flash_status & DOC_CTRL_FLASHREADY)); |
| 81 | |
| 82 | return 0; |
| 83 | } |
| 84 | |
| 85 | static void write_addr(void __iomem *docptr, uint32_t docg4_addr) |
| 86 | { |
| 87 | /* write the four address bytes packed in docg4_addr to the device */ |
| 88 | |
| 89 | writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS); |
| 90 | docg4_addr >>= 8; |
| 91 | writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS); |
| 92 | docg4_addr >>= 8; |
| 93 | writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS); |
| 94 | docg4_addr >>= 8; |
| 95 | writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS); |
| 96 | } |
| 97 | |
| 98 | static void address_sequence(unsigned int g4_page, unsigned int g4_index, |
| 99 | void __iomem *docptr) |
| 100 | { |
| 101 | writew(DOCG4_SEQ_PAGE_READ, docptr + DOC_FLASHSEQUENCE); |
| 102 | writew(DOCG4_CMD_PAGE_READ, docptr + DOC_FLASHCOMMAND); |
| 103 | write_nop(docptr); |
| 104 | write_addr(docptr, ((uint32_t)g4_page << 16) | g4_index); |
| 105 | write_nop(docptr); |
| 106 | } |
| 107 | |
| 108 | static int docg4_load_block_reliable(uint32_t flash_offset, void *dest_addr) |
| 109 | { |
| 110 | void __iomem *docptr = (void *)CONFIG_SYS_NAND_BASE; |
| 111 | unsigned int g4_page = flash_offset >> 11; /* 2k page */ |
| 112 | const unsigned int last_g4_page = g4_page + 0x80; /* last in block */ |
| 113 | int g4_index = 0; |
| 114 | uint16_t flash_status; |
| 115 | uint16_t *buf; |
| 116 | uint16_t discard, magic_high, magic_low; |
| 117 | |
| 118 | /* flash_offset must be aligned to the start of a block */ |
| 119 | if (flash_offset & 0x3ffff) |
| 120 | return -1; |
| 121 | |
| 122 | writew(DOC_SEQ_RESET, docptr + DOC_FLASHSEQUENCE); |
| 123 | writew(DOC_CMD_RESET, docptr + DOC_FLASHCOMMAND); |
| 124 | write_nop(docptr); |
| 125 | write_nop(docptr); |
| 126 | poll_status(docptr); |
| 127 | write_nop(docptr); |
| 128 | writew(0x45, docptr + DOC_FLASHSEQUENCE); |
| 129 | writew(0xa3, docptr + DOC_FLASHCOMMAND); |
| 130 | write_nop(docptr); |
| 131 | writew(0x22, docptr + DOC_FLASHCOMMAND); |
| 132 | write_nop(docptr); |
| 133 | |
| 134 | /* read 1st 4 oob bytes of first subpage of block */ |
| 135 | address_sequence(g4_page, 0x0100, docptr); /* index at oob */ |
| 136 | write_nop(docptr); |
| 137 | flash_status = readw(docptr + DOC_FLASHCONTROL); |
| 138 | flash_status = readw(docptr + DOC_FLASHCONTROL); |
| 139 | if (flash_status & 0x06) /* sequence or protection errors */ |
| 140 | return -1; |
| 141 | writew(DOCG4_CMD_READ2, docptr + DOC_FLASHCOMMAND); |
| 142 | write_nop(docptr); |
| 143 | write_nop(docptr); |
| 144 | poll_status(docptr); |
| 145 | writew(DOC_ECCCONF0_READ_MODE | 4, docptr + DOC_ECCCONF0); |
| 146 | write_nop(docptr); |
| 147 | write_nop(docptr); |
| 148 | write_nop(docptr); |
| 149 | write_nop(docptr); |
| 150 | write_nop(docptr); |
| 151 | |
| 152 | /* |
| 153 | * Here we read the first four oob bytes of the first page of the block. |
| 154 | * The IPL on the palmtreo680 requires that this contain a 32 bit magic |
| 155 | * number, or the load aborts. We'll ignore it. |
| 156 | */ |
| 157 | discard = readw(docptr + 0x103c); /* hw quirk; 1st read discarded */ |
| 158 | magic_low = readw(docptr + 0x103c); |
| 159 | magic_high = readw(docptr + DOCG4_MYSTERY_REG); |
| 160 | writew(0, docptr + DOC_DATAEND); |
| 161 | write_nop(docptr); |
| 162 | write_nop(docptr); |
| 163 | |
| 164 | /* load contents of block to memory */ |
| 165 | buf = (uint16_t *)dest_addr; |
| 166 | do { |
| 167 | int i; |
| 168 | |
| 169 | address_sequence(g4_page, g4_index, docptr); |
| 170 | writew(DOCG4_CMD_READ2, |
| 171 | docptr + DOC_FLASHCOMMAND); |
| 172 | write_nop(docptr); |
| 173 | write_nop(docptr); |
| 174 | poll_status(docptr); |
| 175 | writew(DOC_ECCCONF0_READ_MODE | |
| 176 | DOC_ECCCONF0_ECC_ENABLE | |
| 177 | DOCG4_BCH_SIZE, |
| 178 | docptr + DOC_ECCCONF0); |
| 179 | write_nop(docptr); |
| 180 | write_nop(docptr); |
| 181 | write_nop(docptr); |
| 182 | write_nop(docptr); |
| 183 | write_nop(docptr); |
| 184 | |
| 185 | /* read the 512 bytes of page data, 2 bytes at a time */ |
| 186 | discard = readw(docptr + 0x103c); |
| 187 | for (i = 0; i < 256; i++) |
| 188 | *buf++ = readw(docptr + 0x103c); |
| 189 | |
| 190 | /* read oob, but discard it */ |
| 191 | for (i = 0; i < 7; i++) |
| 192 | discard = readw(docptr + 0x103c); |
| 193 | discard = readw(docptr + DOCG4_OOB_6_7); |
| 194 | discard = readw(docptr + DOCG4_OOB_6_7); |
| 195 | |
| 196 | writew(0, docptr + DOC_DATAEND); |
| 197 | write_nop(docptr); |
| 198 | write_nop(docptr); |
| 199 | |
| 200 | if (!(g4_index & 0x100)) { |
| 201 | /* not redundant subpage read; check for ecc error */ |
| 202 | write_nop(docptr); |
| 203 | flash_status = readw(docptr + DOC_ECCCONF1); |
| 204 | flash_status = readw(docptr + DOC_ECCCONF1); |
| 205 | if (flash_status & 0x80) { /* ecc error */ |
| 206 | g4_index += 0x108; /* read redundant subpage */ |
| 207 | buf -= 256; /* back up ram ptr */ |
| 208 | continue; |
| 209 | } else /* no ecc error */ |
| 210 | g4_index += 0x210; /* skip redundant subpage */ |
| 211 | } else /* redundant page was just read; skip ecc error check */ |
| 212 | g4_index += 0x108; |
| 213 | |
| 214 | if (g4_index == 0x420) { /* finished with 2k page */ |
| 215 | g4_index = 0; |
| 216 | g4_page += 2; /* odd-numbered 2k pages skipped */ |
| 217 | } |
| 218 | |
| 219 | } while (g4_page != last_g4_page); /* while still on same block */ |
| 220 | |
| 221 | return 0; |
| 222 | } |