Re: [PATCH 08/13] mtd: spinand: Reject 8D-8D-8D op_templates if octal_dtr_enale() is missing in manufacturer_op

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On 07/08/21 12:31 am, Miquel Raynal wrote:
Hi Apurva,

Apurva Nandan <a-nandan@xxxxxx> wrote on Tue, 13 Jul 2021 13:05:33
+0000:

The SPI NAND core doesn't know how to switch the flash to Octal DTR
mode (i.e. which operations to perform). If the manufacturer hasn't
implemented the octal_dtr_enable() manufacturer_op, the SPI NAND core
wouldn't be able to switch to 8D-8D-8D mode and will also not be able
to run in 1S-1S-1S mode due to already selected 8D-8D-8D read/write
cache op_templates.

So, avoid choosing a Octal DTR SPI op_template for read_cache,
write_cache and update_cache operations, if the manufacturer_op
octal_dtr_enable() is missing.

After looking at your previous commit I don't see why this patch would
be needed. octal_dtr_enable() only updates the mode when it succeeds so
I don't think this patch is really needed.


I added it to prevent any errors happening dues to a missing implementation of octal_dtr_enable() from manufacturer driver side. So, if the manufacturers skips the octal_dtr_enable() implementation, we want the spinand core to run in 1s-1s-1s mode.

Read/write/update op variant selection happens in select_op_variant(), much before octal_dtr_enable(). So just check if there is a definition of octal_dtr_enable in manufacturer ops and then only use 8D op variants.

Removing this wouldn't break anything in the current implementation.
Do you think we should drop this?


Signed-off-by: Apurva Nandan <a-nandan@xxxxxx>
---
  drivers/mtd/nand/spi/core.c | 7 ++++++-
  1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index 19d8affac058..8711e887b795 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -1028,6 +1028,8 @@ static int spinand_manufacturer_match(struct spinand_device *spinand,
  		if (id[0] != manufacturer->id)
  			continue;
+ spinand->manufacturer = manufacturer;
+
  		ret = spinand_match_and_init(spinand,
  					     manufacturer->chips,
  					     manufacturer->nchips,
@@ -1035,7 +1037,6 @@ static int spinand_manufacturer_match(struct spinand_device *spinand,
  		if (ret < 0)
  			continue;
- spinand->manufacturer = manufacturer;
  		return 0;
  	}
  	return -ENOTSUPP;
@@ -1097,6 +1098,10 @@ spinand_select_op_variant(struct spinand_device *spinand,
  		unsigned int nbytes;
  		int ret;
+ if (spinand_op_is_octal_dtr(&op) &&
+		    !spinand->manufacturer->ops->octal_dtr_enable)
+			continue;
+
  		nbytes = nanddev_per_page_oobsize(nand) +
  			 nanddev_page_size(nand);

Thanks,
Miquèl

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Thanks,
Apurva Nandan



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