Re: [PATCH 1/3] mtd: rawnand: qcom: Update read_loc size to 512

From: Md Sadre Alam
Date: Mon Aug 21 2023 - 01:31:21 EST




On 8/19/2023 1:29 AM, Miquel Raynal wrote:
Hi Md,

quic_mdalam@xxxxxxxxxxx wrote on Fri, 18 Aug 2023 20:20:59 +0530:

For parameter page read upper layer is passing len
as 256 bytes and if we try to configure 256 bytes
size in read loaction register then subsequent bam
transaction is getting timed out for 4K nand devices.
So update this length as one step size if its
less than NANDC_STEP_SIZE.

Signed-off-by: Sricharan Ramabadhran <quic_srichara@xxxxxxxxxxx>
Signed-off-by: Md Sadre Alam <quic_mdalam@xxxxxxxxxxx>

I'm fine with patches 2 and 3 and will take them. But this one does not
seem legitimate. I don't like it. Are you sure the ECC engine was not
enabled when it timed out? Default should be having the ECC disabled
and it should just get enabled when you need it. There is no reason
why, specifically on NAND devices, it would not be possible to read 256
bytes.


Yes default ECC engine is disabled only. When length was 512 bytes for
parameter page read it was causing BAM timeout error on SDX65, but it
was working fine on IPQ807x.
We will drop this patch for now. Let me check on SDX65 and try to fix
all the error.

---
drivers/mtd/nand/raw/qcom_nandc.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
index d4ba0d04c970..413e214c8e87 100644
--- a/drivers/mtd/nand/raw/qcom_nandc.c
+++ b/drivers/mtd/nand/raw/qcom_nandc.c
@@ -2885,6 +2885,9 @@ 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);
+ if (len < NANDC_STEP_SIZE)
+ len = NANDC_STEP_SIZE;
+
nandc_set_read_loc(chip, 0, 0, 0, len, 1);
if (!nandc->props->qpic_v2) {


Thanks,
Miquèl