diff options
Diffstat (limited to 'drivers/mtd/nand/docg4_spl.c')
| -rw-r--r-- | drivers/mtd/nand/docg4_spl.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/drivers/mtd/nand/docg4_spl.c b/drivers/mtd/nand/docg4_spl.c new file mode 100644 index 000000000..95e856c21 --- /dev/null +++ b/drivers/mtd/nand/docg4_spl.c @@ -0,0 +1,222 @@ +/* + * SPL driver for Diskonchip G4 nand flash + * + * Copyright (C) 2013 Mike Dunn <mikedunn@newsguy.com> + * + * This file is released under the terms of GPL v2 and any later version. + * See the file COPYING in the root directory of the source tree for details. + * + * + * This driver basically mimics the load functionality of a typical IPL (initial + * program loader) resident in the 2k NOR-like region of the docg4 that is + * mapped to the reset vector. It allows the u-boot SPL to continue loading if + * the IPL loads a fixed number of flash blocks that is insufficient to contain + * the entire u-boot image. In this case, a concatenated spl + u-boot image is + * written at the flash offset from which the IPL loads an image, and when the + * IPL jumps to the SPL, the SPL resumes loading where the IPL left off. See + * the palmtreo680 for an example. + * + * This driver assumes that the data was written to the flash using the device's + * "reliable" mode, and also assumes that each 512 byte page is stored + * redundantly in the subsequent page. This storage format is likely to be used + * by all boards that boot from the docg4. The format compensates for the lack + * of ecc in the IPL. + * + * Reliable mode reduces the capacity of a block by half, and the redundant + * pages reduce it by half again. As a result, the normal 256k capacity of a + * block is reduced to 64k for the purposes of the IPL/SPL. + */ + +#include <asm/io.h> +#include <linux/mtd/docg4.h> + +/* forward declarations */ +static inline void write_nop(void __iomem *docptr); +static int poll_status(void __iomem *docptr); +static void write_addr(void __iomem *docptr, uint32_t docg4_addr); +static void address_sequence(unsigned int g4_page, unsigned int g4_index, + void __iomem *docptr); +static int docg4_load_block_reliable(uint32_t flash_offset, void *dest_addr); + +int nand_spl_load_image(uint32_t offs, unsigned int size, void *dst) +{ + void *load_addr = dst; + uint32_t flash_offset = offs; + const unsigned int block_count = + (size + DOCG4_BLOCK_CAPACITY_SPL - 1) + / DOCG4_BLOCK_CAPACITY_SPL; + int i; + + for (i = 0; i < block_count; i++) { + int ret = docg4_load_block_reliable(flash_offset, load_addr); + if (ret) + return ret; + load_addr += DOCG4_BLOCK_CAPACITY_SPL; + flash_offset += DOCG4_BLOCK_SIZE; + } + return 0; +} + +static inline void write_nop(void __iomem *docptr) +{ + writew(0, docptr + DOC_NOP); +} + +static int poll_status(void __iomem *docptr) +{ + /* + * Busy-wait for the FLASHREADY bit to be set in the FLASHCONTROL + * register. Operations known to take a long time (e.g., block erase) + * should sleep for a while before calling this. + */ + + uint8_t flash_status; + + /* hardware quirk requires reading twice initially */ + flash_status = readb(docptr + DOC_FLASHCONTROL); + + do { + flash_status = readb(docptr + DOC_FLASHCONTROL); + } while (!(flash_status & DOC_CTRL_FLASHREADY)); + + return 0; +} + +static void write_addr(void __iomem *docptr, uint32_t docg4_addr) +{ + /* write the four address bytes packed in docg4_addr to the device */ + + writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS); + docg4_addr >>= 8; + writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS); + docg4_addr >>= 8; + writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS); + docg4_addr >>= 8; + writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS); +} + +static void address_sequence(unsigned int g4_page, unsigned int g4_index, + void __iomem *docptr) +{ + writew(DOCG4_SEQ_PAGE_READ, docptr + DOC_FLASHSEQUENCE); + writew(DOCG4_CMD_PAGE_READ, docptr + DOC_FLASHCOMMAND); + write_nop(docptr); + write_addr(docptr, ((uint32_t)g4_page << 16) | g4_index); + write_nop(docptr); +} + +static int docg4_load_block_reliable(uint32_t flash_offset, void *dest_addr) +{ + void __iomem *docptr = (void *)CONFIG_SYS_NAND_BASE; + unsigned int g4_page = flash_offset >> 11; /* 2k page */ + const unsigned int last_g4_page = g4_page + 0x80; /* last in block */ + int g4_index = 0; + uint16_t flash_status; + uint16_t *buf; + uint16_t discard, magic_high, magic_low; + + /* flash_offset must be aligned to the start of a block */ + if (flash_offset & 0x3ffff) + return -1; + + writew(DOC_SEQ_RESET, docptr + DOC_FLASHSEQUENCE); + writew(DOC_CMD_RESET, docptr + DOC_FLASHCOMMAND); + write_nop(docptr); + write_nop(docptr); + poll_status(docptr); + write_nop(docptr); + writew(0x45, docptr + DOC_FLASHSEQUENCE); + writew(0xa3, docptr + DOC_FLASHCOMMAND); + write_nop(docptr); + writew(0x22, docptr + DOC_FLASHCOMMAND); + write_nop(docptr); + + /* read 1st 4 oob bytes of first subpage of block */ + address_sequence(g4_page, 0x0100, docptr); /* index at oob */ + write_nop(docptr); + flash_status = readw(docptr + DOC_FLASHCONTROL); + flash_status = readw(docptr + DOC_FLASHCONTROL); + if (flash_status & 0x06) /* sequence or protection errors */ + return -1; + writew(DOCG4_CMD_READ2, docptr + DOC_FLASHCOMMAND); + write_nop(docptr); + write_nop(docptr); + poll_status(docptr); + writew(DOC_ECCCONF0_READ_MODE | 4, docptr + DOC_ECCCONF0); + write_nop(docptr); + write_nop(docptr); + write_nop(docptr); + write_nop(docptr); + write_nop(docptr); + + /* + * Here we read the first four oob bytes of the first page of the block. + * The IPL on the palmtreo680 requires that this contain a 32 bit magic + * number, or the load aborts. We'll ignore it. + */ + discard = readw(docptr + 0x103c); /* hw quirk; 1st read discarded */ + magic_low = readw(docptr + 0x103c); + magic_high = readw(docptr + DOCG4_MYSTERY_REG); + writew(0, docptr + DOC_DATAEND); + write_nop(docptr); + write_nop(docptr); + + /* load contents of block to memory */ + buf = (uint16_t *)dest_addr; + do { + int i; + + address_sequence(g4_page, g4_index, docptr); + writew(DOCG4_CMD_READ2, + docptr + DOC_FLASHCOMMAND); + write_nop(docptr); + write_nop(docptr); + poll_status(docptr); + writew(DOC_ECCCONF0_READ_MODE | + DOC_ECCCONF0_ECC_ENABLE | + DOCG4_BCH_SIZE, + docptr + DOC_ECCCONF0); + write_nop(docptr); + write_nop(docptr); + write_nop(docptr); + write_nop(docptr); + write_nop(docptr); + + /* read the 512 bytes of page data, 2 bytes at a time */ + discard = readw(docptr + 0x103c); + for (i = 0; i < 256; i++) + *buf++ = readw(docptr + 0x103c); + + /* read oob, but discard it */ + for (i = 0; i < 7; i++) + discard = readw(docptr + 0x103c); + discard = readw(docptr + DOCG4_OOB_6_7); + discard = readw(docptr + DOCG4_OOB_6_7); + + writew(0, docptr + DOC_DATAEND); + write_nop(docptr); + write_nop(docptr); + + if (!(g4_index & 0x100)) { + /* not redundant subpage read; check for ecc error */ + write_nop(docptr); + flash_status = readw(docptr + DOC_ECCCONF1); + flash_status = readw(docptr + DOC_ECCCONF1); + if (flash_status & 0x80) { /* ecc error */ + g4_index += 0x108; /* read redundant subpage */ + buf -= 256; /* back up ram ptr */ + continue; + } else /* no ecc error */ + g4_index += 0x210; /* skip redundant subpage */ + } else /* redundant page was just read; skip ecc error check */ + g4_index += 0x108; + + if (g4_index == 0x420) { /* finished with 2k page */ + g4_index = 0; + g4_page += 2; /* odd-numbered 2k pages skipped */ + } + + } while (g4_page != last_g4_page); /* while still on same block */ + + return 0; +} |