in drivers/mtd/nand/raw/nand_base.c [5013:5298]
int nand_scan_tail(struct mtd_info *mtd)
{
int i;
struct nand_chip *chip = mtd_to_nand(mtd);
struct nand_ecc_ctrl *ecc = &chip->ecc;
struct nand_buffers *nbuf;
/* New bad blocks should be marked in OOB, flash-based BBT, or both */
BUG_ON((chip->bbt_options & NAND_BBT_NO_OOB_BBM) &&
!(chip->bbt_options & NAND_BBT_USE_FLASH));
if (invalid_ecc_page_accessors(chip)) {
pr_err("Invalid ECC page accessors setup\n");
return -EINVAL;
}
if (!(chip->options & NAND_OWN_BUFFERS)) {
nbuf = kzalloc(sizeof(struct nand_buffers), GFP_KERNEL);
chip->buffers = nbuf;
} else {
if (!chip->buffers)
return -ENOMEM;
}
/* Set the internal oob buffer location, just after the page data */
chip->oob_poi = chip->buffers->databuf + mtd->writesize;
/*
* If no default placement scheme is given, select an appropriate one.
*/
if (!ecc->layout && (ecc->mode != NAND_ECC_SOFT_BCH)) {
switch (mtd->oobsize) {
#ifndef CONFIG_SYS_NAND_DRIVER_ECC_LAYOUT
case 8:
ecc->layout = &nand_oob_8;
break;
case 16:
ecc->layout = &nand_oob_16;
break;
case 64:
ecc->layout = &nand_oob_64;
break;
case 128:
ecc->layout = &nand_oob_128;
break;
#endif
default:
pr_warn("No oob scheme defined for oobsize %d\n",
mtd->oobsize);
BUG();
}
}
if (!chip->write_page)
chip->write_page = nand_write_page;
/*
* Check ECC mode, default to software if 3byte/512byte hardware ECC is
* selected and we have 256 byte pagesize fallback to software ECC
*/
switch (ecc->mode) {
case NAND_ECC_HW_OOB_FIRST:
/* Similar to NAND_ECC_HW, but a separate read_page handle */
if (!ecc->calculate || !ecc->correct || !ecc->hwctl) {
pr_warn("No ECC functions supplied; hardware ECC not possible\n");
BUG();
}
if (!ecc->read_page)
ecc->read_page = nand_read_page_hwecc_oob_first;
case NAND_ECC_HW:
/* Use standard hwecc read page function? */
if (!ecc->read_page)
ecc->read_page = nand_read_page_hwecc;
if (!ecc->write_page)
ecc->write_page = nand_write_page_hwecc;
if (!ecc->read_page_raw)
ecc->read_page_raw = nand_read_page_raw;
if (!ecc->write_page_raw)
ecc->write_page_raw = nand_write_page_raw;
if (!ecc->read_oob)
ecc->read_oob = nand_read_oob_std;
if (!ecc->write_oob)
ecc->write_oob = nand_write_oob_std;
if (!ecc->read_subpage)
ecc->read_subpage = nand_read_subpage;
if (!ecc->write_subpage && ecc->hwctl && ecc->calculate)
ecc->write_subpage = nand_write_subpage_hwecc;
case NAND_ECC_HW_SYNDROME:
if ((!ecc->calculate || !ecc->correct || !ecc->hwctl) &&
(!ecc->read_page ||
ecc->read_page == nand_read_page_hwecc ||
!ecc->write_page ||
ecc->write_page == nand_write_page_hwecc)) {
pr_warn("No ECC functions supplied; hardware ECC not possible\n");
BUG();
}
/* Use standard syndrome read/write page function? */
if (!ecc->read_page)
ecc->read_page = nand_read_page_syndrome;
if (!ecc->write_page)
ecc->write_page = nand_write_page_syndrome;
if (!ecc->read_page_raw)
ecc->read_page_raw = nand_read_page_raw_syndrome;
if (!ecc->write_page_raw)
ecc->write_page_raw = nand_write_page_raw_syndrome;
if (!ecc->read_oob)
ecc->read_oob = nand_read_oob_syndrome;
if (!ecc->write_oob)
ecc->write_oob = nand_write_oob_syndrome;
if (mtd->writesize >= ecc->size) {
if (!ecc->strength) {
pr_warn("Driver must set ecc.strength when using hardware ECC\n");
BUG();
}
break;
}
pr_warn("%d byte HW ECC not possible on %d byte page size, fallback to SW ECC\n",
ecc->size, mtd->writesize);
ecc->mode = NAND_ECC_SOFT;
case NAND_ECC_SOFT:
ecc->calculate = nand_calculate_ecc;
ecc->correct = nand_correct_data;
ecc->read_page = nand_read_page_swecc;
ecc->read_subpage = nand_read_subpage;
ecc->write_page = nand_write_page_swecc;
ecc->read_page_raw = nand_read_page_raw;
ecc->write_page_raw = nand_write_page_raw;
ecc->read_oob = nand_read_oob_std;
ecc->write_oob = nand_write_oob_std;
if (!ecc->size)
ecc->size = 256;
ecc->bytes = 3;
ecc->strength = 1;
break;
case NAND_ECC_SOFT_BCH:
if (!mtd_nand_has_bch()) {
pr_warn("CONFIG_MTD_NAND_ECC_BCH not enabled\n");
BUG();
}
ecc->calculate = nand_bch_calculate_ecc;
ecc->correct = nand_bch_correct_data;
ecc->read_page = nand_read_page_swecc;
ecc->read_subpage = nand_read_subpage;
ecc->write_page = nand_write_page_swecc;
ecc->read_page_raw = nand_read_page_raw;
ecc->write_page_raw = nand_write_page_raw;
ecc->read_oob = nand_read_oob_std;
ecc->write_oob = nand_write_oob_std;
/*
* Board driver should supply ecc.size and ecc.strength values
* to select how many bits are correctable. Otherwise, default
* to 4 bits for large page devices.
*/
if (!ecc->size && (mtd->oobsize >= 64)) {
ecc->size = 512;
ecc->strength = 4;
}
/* See nand_bch_init() for details. */
ecc->bytes = 0;
ecc->priv = nand_bch_init(mtd);
if (!ecc->priv) {
pr_warn("BCH ECC initialization failed!\n");
BUG();
}
break;
case NAND_ECC_NONE:
pr_warn("NAND_ECC_NONE selected by board driver. This is not recommended!\n");
ecc->read_page = nand_read_page_raw;
ecc->write_page = nand_write_page_raw;
ecc->read_oob = nand_read_oob_std;
ecc->read_page_raw = nand_read_page_raw;
ecc->write_page_raw = nand_write_page_raw;
ecc->write_oob = nand_write_oob_std;
ecc->size = mtd->writesize;
ecc->bytes = 0;
ecc->strength = 0;
break;
default:
pr_warn("Invalid NAND_ECC_MODE %d\n", ecc->mode);
BUG();
}
/* For many systems, the standard OOB write also works for raw */
if (!ecc->read_oob_raw)
ecc->read_oob_raw = ecc->read_oob;
if (!ecc->write_oob_raw)
ecc->write_oob_raw = ecc->write_oob;
/*
* The number of bytes available for a client to place data into
* the out of band area.
*/
mtd->oobavail = 0;
if (ecc->layout) {
for (i = 0; ecc->layout->oobfree[i].length; i++)
mtd->oobavail += ecc->layout->oobfree[i].length;
}
/* ECC sanity check: warn if it's too weak */
if (!nand_ecc_strength_good(mtd))
pr_warn("WARNING: %s: the ECC used on your system is too weak compared to the one required by the NAND chip\n",
mtd->name);
/*
* Set the number of read / write steps for one page depending on ECC
* mode.
*/
ecc->steps = mtd->writesize / ecc->size;
if (ecc->steps * ecc->size != mtd->writesize) {
pr_warn("Invalid ECC parameters\n");
BUG();
}
ecc->total = ecc->steps * ecc->bytes;
/* Allow subpage writes up to ecc.steps. Not possible for MLC flash */
if (!(chip->options & NAND_NO_SUBPAGE_WRITE) && nand_is_slc(chip)) {
switch (ecc->steps) {
case 2:
mtd->subpage_sft = 1;
break;
case 4:
case 8:
case 16:
mtd->subpage_sft = 2;
break;
}
}
chip->subpagesize = mtd->writesize >> mtd->subpage_sft;
/* Initialize state */
chip->state = FL_READY;
/* Invalidate the pagebuffer reference */
chip->pagebuf = -1;
/* Large page NAND with SOFT_ECC should support subpage reads */
switch (ecc->mode) {
case NAND_ECC_SOFT:
case NAND_ECC_SOFT_BCH:
if (chip->page_shift > 9)
chip->options |= NAND_SUBPAGE_READ;
break;
default:
break;
}
/* Fill in remaining MTD driver data */
mtd->type = nand_is_slc(chip) ? MTD_NANDFLASH : MTD_MLCNANDFLASH;
mtd->flags = (chip->options & NAND_ROM) ? MTD_CAP_ROM :
MTD_CAP_NANDFLASH;
mtd->_erase = nand_erase;
mtd->_panic_write = panic_nand_write;
mtd->_read_oob = nand_read_oob;
mtd->_write_oob = nand_write_oob;
mtd->_sync = nand_sync;
mtd->_lock = NULL;
mtd->_unlock = NULL;
mtd->_block_isreserved = nand_block_isreserved;
mtd->_block_isbad = nand_block_isbad;
mtd->_block_markbad = nand_block_markbad;
mtd->writebufsize = mtd->writesize;
/* propagate ecc info to mtd_info */
mtd->ecclayout = ecc->layout;
mtd->ecc_strength = ecc->strength;
mtd->ecc_step_size = ecc->size;
/*
* Initialize bitflip_threshold to its default prior scan_bbt() call.
* scan_bbt() might invoke mtd_read(), thus bitflip_threshold must be
* properly set.
*/
if (!mtd->bitflip_threshold)
mtd->bitflip_threshold = DIV_ROUND_UP(mtd->ecc_strength * 3, 4);
return 0;
}