[PATCH 09/10] mtd: rawnand: jedec: Add an alternative parameter page read

[Miquel Raynal <miquel.raynal@xxxxxxxxxxx>]

Some controllers are not able to read the parameter page in separate chunks.

As there is no need for separate parameter page reads (the delay penalty
for reading the three copies in one go being negligible), the
temptation to just do a monolithic read is high.

But we are afraid of controllers not supporting reading a parameter
page of 1536 bytes neither.

So, despite darkening a little bit this portion, the final solution to
support as many controllers as possible is to check if there is an
actual need for such monolithic read, otherwise we keep the current
behavior.

Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
---
 drivers/mtd/nand/raw/nand_jedec.c | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/drivers/mtd/nand/raw/nand_jedec.c b/drivers/mtd/nand/raw/nand_jedec.c
index 15937e02c64f..c88a5f1049d2 100644
--- a/drivers/mtd/nand/raw/nand_jedec.c
+++ b/drivers/mtd/nand/raw/nand_jedec.c
@@ -25,7 +25,7 @@ int nand_jedec_detect(struct nand_chip *chip)
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	struct nand_memory_organization *memorg;
-	struct nand_jedec_params *p;
+	struct nand_jedec_params *p = NULL, *pbuf;
 	struct jedec_ecc_info *ecc;
 	int jedec_version = 0;
 	char id[5];
@@ -40,25 +40,32 @@ int nand_jedec_detect(struct nand_chip *chip)
 		return 0;
 
 	/* JEDEC chip: allocate a buffer to hold its parameter page */
-	p = kzalloc(sizeof(*p), GFP_KERNEL);
-	if (!p)
+	pbuf = kzalloc(sizeof(*pbuf) * JEDEC_PARAM_PAGES, GFP_KERNEL);
+	if (!pbuf)
 		return -ENOMEM;
 
-	ret = nand_read_param_page_op(chip, 0x40, NULL, 0);
+	if (nand_pack_ops(chip))
+		ret = nand_read_param_page_op(chip, 0x40, pbuf,
+					      sizeof(*pbuf) * JEDEC_PARAM_PAGES);
+	else
+		ret = nand_read_param_page_op(chip, 0x40, NULL, 0);
 	if (ret) {
 		ret = 0;
 		goto free_jedec_param_page;
 	}
 
 	for (i = 0; i < JEDEC_PARAM_PAGES; i++) {
-		ret = nand_read_data_op(chip, p, sizeof(*p), true);
-		if (ret) {
-			ret = 0;
-			goto free_jedec_param_page;
+		if (!nand_pack_ops(chip)) {
+			ret = nand_read_data_op(chip, &pbuf[i], sizeof(*pbuf),
+						true);
+			if (ret) {
+				ret = 0;
+				goto free_jedec_param_page;
+			}
 		}
 
-		crc = onfi_crc16(ONFI_CRC_BASE, (u8 *)p, 510);
-		if (crc == le16_to_cpu(p->crc))
+		crc = onfi_crc16(ONFI_CRC_BASE, (u8 *)&pbuf[i], 510);
+		if (crc == le16_to_cpu(pbuf[i].crc))
 			break;
 	}
 
@@ -67,6 +74,8 @@ int nand_jedec_detect(struct nand_chip *chip)
 		goto free_jedec_param_page;
 	}
 
+	p = pbuf;
+
 	/* Check version */
 	val = le16_to_cpu(p->revision);
 	if (val & (1 << 2))
@@ -122,6 +131,6 @@ int nand_jedec_detect(struct nand_chip *chip)
 	ret = 1;
 
 free_jedec_param_page:
-	kfree(p);
+	kfree(pbuf);
 	return ret;
 }
-- 
2.20.1


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