[MTD] [NAND] remove len/ooblen confusion.
As was discussed between Ricard Wanderlöf, David Woodhouse, Artem
Bityutskiy and me, the current API for reading/writing OOB is confusing.
The thing that introduces confusion is the need to specify ops.len
together with ops.ooblen for reads/writes that concern only OOB not data
area. So, ops.len is overloaded: when ops.datbuf != NULL it serves to
specify the length of the data read, and when ops.datbuf == NULL, it
serves to specify the full OOB read length.
The patch inlined below is the slightly updated version of the previous
patch serving the same purpose, but with the new Artem's comments taken
into account.
Artem, BTW, thanks a lot for your valuable input!
Signed-off-by: Vitaly Wool <vwool@ru.mvista.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 8df36e2..5dcb2e0 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -897,12 +897,11 @@
* @chip: nand chip structure
* @oob: oob destination address
* @ops: oob ops structure
+ * @len: size of oob to transfer
*/
static uint8_t *nand_transfer_oob(struct nand_chip *chip, uint8_t *oob,
- struct mtd_oob_ops *ops)
+ struct mtd_oob_ops *ops, size_t len)
{
- size_t len = ops->ooblen;
-
switch(ops->mode) {
case MTD_OOB_PLACE:
@@ -960,6 +959,7 @@
int sndcmd = 1;
int ret = 0;
uint32_t readlen = ops->len;
+ uint32_t oobreadlen = ops->ooblen;
uint8_t *bufpoi, *oob, *buf;
stats = mtd->ecc_stats;
@@ -1006,10 +1006,17 @@
if (unlikely(oob)) {
/* Raw mode does data:oob:data:oob */
- if (ops->mode != MTD_OOB_RAW)
- oob = nand_transfer_oob(chip, oob, ops);
- else
- buf = nand_transfer_oob(chip, buf, ops);
+ if (ops->mode != MTD_OOB_RAW) {
+ int toread = min(oobreadlen,
+ chip->ecc.layout->oobavail);
+ if (toread) {
+ oob = nand_transfer_oob(chip,
+ oob, ops, toread);
+ oobreadlen -= toread;
+ }
+ } else
+ buf = nand_transfer_oob(chip,
+ buf, ops, mtd->oobsize);
}
if (!(chip->options & NAND_NO_READRDY)) {
@@ -1056,6 +1063,8 @@
}
ops->retlen = ops->len - (size_t) readlen;
+ if (oob)
+ ops->oobretlen = ops->ooblen - oobreadlen;
if (ret)
return ret;
@@ -1256,12 +1265,18 @@
int page, realpage, chipnr, sndcmd = 1;
struct nand_chip *chip = mtd->priv;
int blkcheck = (1 << (chip->phys_erase_shift - chip->page_shift)) - 1;
- int readlen = ops->len;
+ int readlen = ops->ooblen;
+ int len;
uint8_t *buf = ops->oobbuf;
DEBUG(MTD_DEBUG_LEVEL3, "nand_read_oob: from = 0x%08Lx, len = %i\n",
(unsigned long long)from, readlen);
+ if (ops->mode == MTD_OOB_RAW)
+ len = mtd->oobsize;
+ else
+ len = chip->ecc.layout->oobavail;
+
chipnr = (int)(from >> chip->chip_shift);
chip->select_chip(mtd, chipnr);
@@ -1271,7 +1286,9 @@
while(1) {
sndcmd = chip->ecc.read_oob(mtd, chip, page, sndcmd);
- buf = nand_transfer_oob(chip, buf, ops);
+
+ len = min(len, readlen);
+ buf = nand_transfer_oob(chip, buf, ops, len);
if (!(chip->options & NAND_NO_READRDY)) {
/*
@@ -1286,7 +1303,7 @@
nand_wait_ready(mtd);
}
- readlen -= ops->ooblen;
+ readlen -= len;
if (!readlen)
break;
@@ -1308,7 +1325,7 @@
sndcmd = 1;
}
- ops->retlen = ops->len;
+ ops->oobretlen = ops->ooblen;
return 0;
}
@@ -1329,7 +1346,7 @@
ops->retlen = 0;
/* Do not allow reads past end of device */
- if ((from + ops->len) > mtd->size) {
+ if (ops->datbuf && (from + ops->len) > mtd->size) {
DEBUG(MTD_DEBUG_LEVEL0, "nand_read_oob: "
"Attempt read beyond end of device\n");
return -EINVAL;
@@ -1654,6 +1671,8 @@
}
ops->retlen = ops->len - writelen;
+ if (unlikely(oob))
+ ops->oobretlen = ops->ooblen;
return ret;
}
@@ -1709,10 +1728,10 @@
struct nand_chip *chip = mtd->priv;
DEBUG(MTD_DEBUG_LEVEL3, "nand_write_oob: to = 0x%08x, len = %i\n",
- (unsigned int)to, (int)ops->len);
+ (unsigned int)to, (int)ops->ooblen);
/* Do not allow write past end of page */
- if ((ops->ooboffs + ops->len) > mtd->oobsize) {
+ if ((ops->ooboffs + ops->ooblen) > mtd->oobsize) {
DEBUG(MTD_DEBUG_LEVEL0, "nand_write_oob: "
"Attempt to write past end of page\n");
return -EINVAL;
@@ -1748,7 +1767,7 @@
if (status)
return status;
- ops->retlen = ops->len;
+ ops->oobretlen = ops->ooblen;
return 0;
}
@@ -1768,7 +1787,7 @@
ops->retlen = 0;
/* Do not allow writes past end of device */
- if ((to + ops->len) > mtd->size) {
+ if (ops->datbuf && (to + ops->len) > mtd->size) {
DEBUG(MTD_DEBUG_LEVEL0, "nand_read_oob: "
"Attempt read beyond end of device\n");
return -EINVAL;