[PATCH v3 10/13] mtd: rawnand: jedec: Adapt the parameter page read to constraint controllers

[Miquel Raynal <miquel.raynal@xxxxxxxxxxx>]

We already know that there are controllers not able to read the three
copies of the parameter page in one go. The workaround was to first
request the controller to assert command and address cycles on the
NAND bus to trigger a parameter page read, and then do a read
operation for each page.

But there are also controllers which are not able to split the
parameter page read between the command/address cycles and the actual
data operation.

Let's use a regular PARAMETER PAGE READ operation for the first
iteration and use eithe a CHANGE READ COLUMN or a simple DATA READ
operation for the following copies, depending on what the controller
supports. The default for non-exec-op compliant drivers remains
unchanged: use a SIMPLE READ.

Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
---
 drivers/mtd/nand/raw/nand_jedec.c | 34 ++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/drivers/mtd/nand/raw/nand_jedec.c b/drivers/mtd/nand/raw/nand_jedec.c
index 63069f1948a8..be270b36317e 100644
--- a/drivers/mtd/nand/raw/nand_jedec.c
+++ b/drivers/mtd/nand/raw/nand_jedec.c
@@ -25,8 +25,9 @@ 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;
+	bool use_datain = false;
 	int jedec_version = 0;
 	char id[5];
 	int i, val, ret;
@@ -40,25 +41,32 @@ 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 (ret) {
-		ret = 0;
-		goto free_jedec_param_page;
-	}
+	if (!nand_has_exec_op(chip) ||
+	    (nand_read_data_op(chip, &pbuf[0], sizeof(*pbuf), true, true) == 0))
+		use_datain = true;
 
 	for (i = 0; i < JEDEC_PARAM_PAGES; i++) {
-		ret = nand_read_data_op(chip, p, sizeof(*p), true, false);
+		if (!i)
+			ret = nand_read_param_page_op(chip, 0x40, &pbuf[i],
+						      sizeof(*pbuf));
+		else if (use_datain)
+			ret = nand_read_data_op(chip, &pbuf[i], sizeof(*pbuf),
+						true, false);
+		else
+			ret = nand_change_read_column_op(chip, sizeof(*pbuf) * i,
+							 &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 +75,8 @@ int nand_jedec_detect(struct nand_chip *chip)
 		goto free_jedec_param_page;
 	}
 
+	p = &pbuf[i];
+
 	/* Check version */
 	val = le16_to_cpu(p->revision);
 	if (val & (1 << 2))
@@ -122,6 +132,6 @@ 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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