diff mbox series

[v8,10/17] mtd: rawnand: sunxi: use page reads to reposition small-page NAND

Message ID 20261015-submit-sunxi-nand-vendor-oob-layout-v1-v8-10-8ba4881fbee8@gmail.com (mailing list archive)
State New
Headers
Series mtd: rawnand: sunxi: fix transfers and support randomized OOB |

Commit Message

James Hilliard Oct. 16, 2026, 3:45 a.m. UTC 
The hardware-ECC reader moves between main data and OOB, and rereads raw
bytes when checking a possibly erased ECC step. It uses
nand_change_read_column_op(), which sends large-page random-output
commands and rejects NAND pages of 512 bytes or less. For a small-page
geometry accepted by hardware-ECC setup, these reads therefore fail when
they need to reposition, rather than using the small-page read commands.

Add a read-column helper that uses nand_read_page_op() on small pages.
The core selects READ0, READ1 or READOOB for the requested column and
sends the row address again. Pass the page number through the
erased-check path as well, and preserve errors from the resulting
operation. Keep the existing random-column operation for larger pages.

Select PIO for small pages even when DMA is available: the DMA PAGE_OP
sequencer uses large-page random-column commands internally.
This corrects read-side repositioning only; the write-column helper still
rejects small pages. Software-ECC and raw callbacks are unchanged.

This is a command-path correction found by inspection, not a claim that
ordinary 512+16 NAND becomes supported. The existing controller-ECC
limits still apply: it needs 512-byte ECC support and at least 28 parity
bytes plus four user-data bytes, so 512+16 remains rejected. No
small-page hardware validation is claimed.

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
 drivers/mtd/nand/raw/sunxi_nand.c | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)
diff mbox series

Patch

diff --git a/drivers/mtd/nand/raw/sunxi_nand.c b/drivers/mtd/nand/raw/sunxi_nand.c
index 9f03ba22b4b7..34c1c5037b11 100644
--- a/drivers/mtd/nand/raw/sunxi_nand.c
+++ b/drivers/mtd/nand/raw/sunxi_nand.c
@@ -1061,6 +1061,16 @@  static void sunxi_nfc_hw_ecc_update_stats(struct nand_chip *nand,
 	}
 }
 
+static int sunxi_nfc_read_column(struct nand_chip *nand, int page,
+				 unsigned int column, void *buf, unsigned int len)
+{
+	/* Small-page NAND needs a new READ0/READ1/READOOB and the page address. */
+	if (nand_to_mtd(nand)->writesize <= 512)
+		return nand_read_page_op(nand, page, column, buf, len);
+
+	return nand_change_read_column_op(nand, column, buf, len, false);
+}
+
 /*
  * Return 1 for an erased chunk or 0 for an uncorrectable chunk, with ECC
  * statistics updated in either case. Negative values report transport errors.
@@ -1069,7 +1079,7 @@  static int sunxi_nfc_hw_ecc_read_error(struct nand_chip *nand,
 				       u8 *data, int data_off,
 				       u8 *oob, int oob_off,
 				       unsigned int user_data_sz,
-				       unsigned int *max_bitflips)
+				       unsigned int *max_bitflips, int page)
 {
 	struct nand_ecc_ctrl *ecc = &nand->ecc;
 	unsigned int oob_len = ecc->bytes + user_data_sz;
@@ -1077,13 +1087,12 @@  static int sunxi_nfc_hw_ecc_read_error(struct nand_chip *nand,
 
 	/* Check the physical representation for bitflips in erased pages. */
 	if (nand->options & NAND_NEED_SCRAMBLING) {
-		ret = nand_change_read_column_op(nand, data_off, data,
-						 ecc->size, false);
+		ret = sunxi_nfc_read_column(nand, page, data_off, data, ecc->size);
 		if (ret)
 			return ret;
 	}
 
-	ret = nand_change_read_column_op(nand, oob_off, oob, oob_len, false);
+	ret = sunxi_nfc_read_column(nand, page, oob_off, oob, oob_len);
 	if (ret)
 		return ret;
 
@@ -1184,8 +1193,8 @@  static int sunxi_nfc_hw_ecc_read_extra_oob(struct nand_chip *nand,
 		return 0;
 
 	if (!cur_off || *cur_off != (offset + mtd->writesize)) {
-		ret = nand_change_read_column_op(nand, mtd->writesize + offset,
-						 NULL, 0, false);
+		ret = sunxi_nfc_read_column(nand, page, mtd->writesize + offset,
+					    NULL, 0);
 		if (ret)
 			return ret;
 	}
@@ -1250,10 +1259,9 @@  static int sunxi_nfc_oob_read_batch(struct nand_chip *nand,
 
 		if (read->oob_required) {
 			/* Keep the existing PIO and DMA representations of parity. */
-			ret = nand_change_read_column_op(nand, mtd->writesize + oob_off,
-							 read->dma ? oob : NULL,
-							 read->dma ? ecc->bytes + user_data_sz : 0,
-							 false);
+			ret = sunxi_nfc_read_column(nand, read->page, mtd->writesize + oob_off,
+						    read->dma ? oob : NULL,
+						    read->dma ? ecc->bytes + user_data_sz : 0);
 			if (ret)
 				return ret;
 
@@ -1289,7 +1297,7 @@  static int sunxi_nfc_oob_read_batch(struct nand_chip *nand,
 		ret = sunxi_nfc_hw_ecc_read_error(nand, read->buf + data_off, data_off,
 						  nand->oob_poi + oob_off,
 						  mtd->writesize + oob_off, user_data_sz,
-						  &read->max_bitflips);
+						  &read->max_bitflips, read->page);
 		if (ret < 0)
 			return ret;
 		if (ret)
@@ -1329,7 +1337,7 @@  static int sunxi_nfc_hw_ecc_read_chunk(struct nand_chip *nand,
 	int ret;
 
 	if (*cur_off != data_off) {
-		ret = nand_change_read_column_op(nand, data_off, NULL, 0, false);
+		ret = sunxi_nfc_read_column(nand, page, data_off, NULL, 0);
 		if (ret)
 			return ret;
 	}
@@ -1339,7 +1347,7 @@  static int sunxi_nfc_hw_ecc_read_chunk(struct nand_chip *nand,
 		return ret;
 
 	if (data_off + ecc->size != oob_off) {
-		ret = nand_change_read_column_op(nand, oob_off, NULL, 0, false);
+		ret = sunxi_nfc_read_column(nand, page, oob_off, NULL, 0);
 		if (ret)
 			return ret;
 	}
@@ -2312,7 +2320,8 @@  static int sunxi_nand_hw_ecc_ctrl_init(struct nand_chip *nand,
 	ecc->write_oob = sunxi_nfc_hw_ecc_write_oob;
 	mtd_set_ooblayout(mtd, &sunxi_nand_ooblayout_ops);
 
-	if (nfc->dmac || nfc->use_mdma) {
+	/* The DMA page sequencer uses large-page random-column commands. */
+	if (mtd->writesize > 512 && (nfc->dmac || nfc->use_mdma)) {
 		ecc->read_page = sunxi_nfc_hw_ecc_read_page_dma;
 		ecc->read_subpage = sunxi_nfc_hw_ecc_read_subpage_dma;
 		ecc->write_page = sunxi_nfc_hw_ecc_write_page_dma;