[PATCH v3 2/4] mtd: rawnand: qcom: Fix last codeword read in qcom_param_page_type_exec()

[Md Sadre Alam]

For QPIC V2 onwards there is a separate register to read
last code word "QPIC_NAND_READ_LOCATION_LAST_CW_n".

qcom_param_page_type_exec() is used to read only one code word
If it configures the number of code words to 1 in QPIC_NAND_DEV0_CFG0
register then QPIC controller thinks its reading the last code word,
since we are having separate register to read the last code word,
we have to configure "QPIC_NAND_READ_LOCATION_LAST_CW_n" register
to fetch data from QPIC buffer to system memory.

Without this change page read was failing with timeout error

/ # hexdump -C /dev/mtd1
[  129.206113] qcom-nandc 1cc8000.nand-controller: failure to read page/oob
hexdump: /dev/mtd1: Connection timed out

This issue only seen on SDX targets since SDX target used QPICv2. But
same working on IPQ targets since IPQ used QPICv1.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 89550beb098e ("mtd: rawnand: qcom: Implement exec_op()")
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Tested-by: Lakshmi Sowjanya D <quic_laksd@xxxxxxxxxxx>
Signed-off-by: Md Sadre Alam <quic_mdalam@xxxxxxxxxxx>
---

Change in [v3]

* Updated commit header and message

* Added condition check for location register
  and location_last register based on qpic_version2

* Added Reviewed-by tag

Change in [v2]

* Updated commit message

* Added stable kernel tag

* Replaced the buf_count value of 512 with the len in bytes.

Change in [v1]

* Resolved the issue with reading a single code word in the parameter
  page read

 drivers/mtd/nand/raw/qcom_nandc.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
index 5443cb918e0b..d41c0e3926ed 100644
--- a/drivers/mtd/nand/raw/qcom_nandc.c
+++ b/drivers/mtd/nand/raw/qcom_nandc.c
@@ -1863,7 +1863,12 @@ static int qcom_param_page_type_exec(struct nand_chip *chip,  const struct nand_
 	const struct nand_op_instr *instr = NULL;
 	unsigned int op_id = 0;
 	unsigned int len = 0;
-	int ret;
+	int ret, reg_base;
+
+	reg_base = NAND_READ_LOCATION_0;
+
+	if (nandc->props->qpic_version2)
+		reg_base = NAND_READ_LOCATION_LAST_CW_0;
 
 	ret = qcom_parse_instructions(chip, subop, &q_op);
 	if (ret)
@@ -1915,7 +1920,10 @@ static int qcom_param_page_type_exec(struct nand_chip *chip,  const struct nand_
 	op_id = q_op.data_instr_idx;
 	len = nand_subop_get_data_len(subop, op_id);
 
-	nandc_set_read_loc(chip, 0, 0, 0, len, 1);
+	if (nandc->props->qpic_version2)
+		nandc_set_read_loc_last(chip, reg_base, 0, len, 1);
+	else
+		nandc_set_read_loc_first(chip, reg_base, 0, len, 1);
 
 	if (!nandc->props->qpic_version2) {
 		qcom_write_reg_dma(nandc, &nandc->regs->vld, NAND_DEV_CMD_VLD, 1, 0);
-- 
2.34.1