aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/mtd/nand/nand_base.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/mtd/nand/nand_base.c')
-rw-r--r--drivers/mtd/nand/nand_base.c104
1 files changed, 86 insertions, 18 deletions
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 9d01c4df838c..41167e9e991e 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -37,6 +37,7 @@
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/mm.h>
#include <linux/types.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
@@ -1204,8 +1205,7 @@ static int nand_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
* ecc.pos. Let's make sure that there are no gaps in ECC positions.
*/
for (i = 0; i < eccfrag_len - 1; i++) {
- if (eccpos[i + start_step * chip->ecc.bytes] + 1 !=
- eccpos[i + start_step * chip->ecc.bytes + 1]) {
+ if (eccpos[i + index] + 1 != eccpos[i + index + 1]) {
gaps = 1;
break;
}
@@ -1501,6 +1501,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
mtd->oobavail : mtd->oobsize;
uint8_t *bufpoi, *oob, *buf;
+ int use_bufpoi;
unsigned int max_bitflips = 0;
int retry_mode = 0;
bool ecc_fail = false;
@@ -1523,9 +1524,20 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
bytes = min(mtd->writesize - col, readlen);
aligned = (bytes == mtd->writesize);
+ if (!aligned)
+ use_bufpoi = 1;
+ else if (chip->options & NAND_USE_BOUNCE_BUFFER)
+ use_bufpoi = !virt_addr_valid(buf);
+ else
+ use_bufpoi = 0;
+
/* Is the current page in the buffer? */
if (realpage != chip->pagebuf || oob) {
- bufpoi = aligned ? buf : chip->buffers->databuf;
+ bufpoi = use_bufpoi ? chip->buffers->databuf : buf;
+
+ if (use_bufpoi && aligned)
+ pr_debug("%s: using read bounce buffer for buf@%p\n",
+ __func__, buf);
read_retry:
chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
@@ -1547,7 +1559,7 @@ read_retry:
ret = chip->ecc.read_page(mtd, chip, bufpoi,
oob_required, page);
if (ret < 0) {
- if (!aligned)
+ if (use_bufpoi)
/* Invalidate page cache */
chip->pagebuf = -1;
break;
@@ -1556,7 +1568,7 @@ read_retry:
max_bitflips = max_t(unsigned int, max_bitflips, ret);
/* Transfer not aligned data */
- if (!aligned) {
+ if (use_bufpoi) {
if (!NAND_HAS_SUBPAGE_READ(chip) && !oob &&
!(mtd->ecc_stats.failed - ecc_failures) &&
(ops->mode != MTD_OPS_RAW)) {
@@ -2376,11 +2388,23 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to,
int bytes = mtd->writesize;
int cached = writelen > bytes && page != blockmask;
uint8_t *wbuf = buf;
+ int use_bufpoi;
+ int part_pagewr = (column || writelen < (mtd->writesize - 1));
+
+ if (part_pagewr)
+ use_bufpoi = 1;
+ else if (chip->options & NAND_USE_BOUNCE_BUFFER)
+ use_bufpoi = !virt_addr_valid(buf);
+ else
+ use_bufpoi = 0;
- /* Partial page write? */
- if (unlikely(column || writelen < (mtd->writesize - 1))) {
+ /* Partial page write?, or need to use bounce buffer */
+ if (use_bufpoi) {
+ pr_debug("%s: using write bounce buffer for buf@%p\n",
+ __func__, buf);
cached = 0;
- bytes = min_t(int, bytes - column, (int) writelen);
+ if (part_pagewr)
+ bytes = min_t(int, bytes - column, writelen);
chip->pagebuf = -1;
memset(chip->buffers->databuf, 0xff, mtd->writesize);
memcpy(&chip->buffers->databuf[column], buf, bytes);
@@ -2618,18 +2642,20 @@ out:
}
/**
- * single_erase_cmd - [GENERIC] NAND standard block erase command function
+ * single_erase - [GENERIC] NAND standard block erase command function
* @mtd: MTD device structure
* @page: the page address of the block which will be erased
*
- * Standard erase command for NAND chips.
+ * Standard erase command for NAND chips. Returns NAND status.
*/
-static void single_erase_cmd(struct mtd_info *mtd, int page)
+static int single_erase(struct mtd_info *mtd, int page)
{
struct nand_chip *chip = mtd->priv;
/* Send commands to erase a block */
chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page);
chip->cmdfunc(mtd, NAND_CMD_ERASE2, -1, -1);
+
+ return chip->waitfunc(mtd, chip);
}
/**
@@ -2710,9 +2736,7 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
(page + pages_per_block))
chip->pagebuf = -1;
- chip->erase_cmd(mtd, page & chip->pagemask);
-
- status = chip->waitfunc(mtd, chip);
+ status = chip->erase(mtd, page & chip->pagemask);
/*
* See if operation failed and additional status checks are
@@ -3607,7 +3631,7 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
chip->onfi_version = 0;
if (!type->name || !type->pagesize) {
- /* Check is chip is ONFI compliant */
+ /* Check if the chip is ONFI compliant */
if (nand_flash_detect_onfi(mtd, chip, &busw))
goto ident_done;
@@ -3685,7 +3709,7 @@ ident_done:
}
chip->badblockbits = 8;
- chip->erase_cmd = single_erase_cmd;
+ chip->erase = single_erase;
/* Do not replace user supplied command function! */
if (mtd->writesize > 512 && chip->cmdfunc == nand_command)
@@ -3770,6 +3794,39 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips,
}
EXPORT_SYMBOL(nand_scan_ident);
+/*
+ * Check if the chip configuration meet the datasheet requirements.
+
+ * If our configuration corrects A bits per B bytes and the minimum
+ * required correction level is X bits per Y bytes, then we must ensure
+ * both of the following are true:
+ *
+ * (1) A / B >= X / Y
+ * (2) A >= X
+ *
+ * Requirement (1) ensures we can correct for the required bitflip density.
+ * Requirement (2) ensures we can correct even when all bitflips are clumped
+ * in the same sector.
+ */
+static bool nand_ecc_strength_good(struct mtd_info *mtd)
+{
+ struct nand_chip *chip = mtd->priv;
+ struct nand_ecc_ctrl *ecc = &chip->ecc;
+ int corr, ds_corr;
+
+ if (ecc->size == 0 || chip->ecc_step_ds == 0)
+ /* Not enough information */
+ return true;
+
+ /*
+ * We get the number of corrected bits per page to compare
+ * the correction density.
+ */
+ corr = (mtd->writesize * ecc->strength) / ecc->size;
+ ds_corr = (mtd->writesize * chip->ecc_strength_ds) / chip->ecc_step_ds;
+
+ return corr >= ds_corr && ecc->strength >= chip->ecc_strength_ds;
+}
/**
* nand_scan_tail - [NAND Interface] Scan for the NAND device
@@ -3990,6 +4047,9 @@ int nand_scan_tail(struct mtd_info *mtd)
ecc->layout->oobavail += ecc->layout->oobfree[i].length;
mtd->oobavail = ecc->layout->oobavail;
+ /* ECC sanity check: warn noisily if it's too weak */
+ WARN_ON(!nand_ecc_strength_good(mtd));
+
/*
* Set the number of read / write steps for one page depending on ECC
* mode.
@@ -4023,8 +4083,16 @@ int nand_scan_tail(struct mtd_info *mtd)
chip->pagebuf = -1;
/* Large page NAND with SOFT_ECC should support subpage reads */
- if ((ecc->mode == NAND_ECC_SOFT) && (chip->page_shift > 9))
- chip->options |= NAND_SUBPAGE_READ;
+ 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;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.