Re: [RESEND v5 09/21] mtd: rawnand: Create a new enumeration to describe properly ECC types

Boris Brezillon [off-list ref] wrote on Wed, 27 May
2020 00:59:28 +0200:

On Tue, 26 May 2020 21:56:21 +0200
Miquel Raynal [off-list ref] wrote:

quoted

Now that the misleading mix between ECC engine type and OOB placement
has been addressed, add a new enumeration to properly define ECC types
(also called provider or mode).

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
---
 drivers/mtd/nand/raw/nand_base.c |  7 +++++++
 include/linux/mtd/rawnand.h      | 16 ++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 515cd4681660..5c6ab5b93270 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c

@@ -5018,6 +5018,13 @@ static const char * const nand_ecc_modes[] = {
 	[NAND_ECC_ON_DIE]	= "on-die",
 };
 
+static const char * const nand_ecc_engine_providers[] = {  

This table is not used here, are you sure it should be introduced now?

quoted

+	[NAND_ECC_ENGINE_NONE] = "none",
+	[NAND_ECC_ENGINE_SOFT] = "soft",
+	[NAND_ECC_ENGINE_CONTROLLER] = "hw",  

					^ "on-controller" ?

This would break DT backward compatibility, I am afraid I cannot do
that. Honnestly, I find "hw" good enough because "on-controller" is
also too restrictive. What about an external (non-pipelined) engine
like the one I am about to introduce?

quoted

+	[NAND_ECC_ENGINE_ON_DIE] = "on-die",
+};
+
 static const char * const nand_ecc_placement[] = {
 	[NAND_ECC_PLACEMENT_INTERLEAVED] = "interleaved",
 };

diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
index dc909fb977c7..a2078c5f3d21 100644
--- a/include/linux/mtd/rawnand.h
+++ b/include/linux/mtd/rawnand.h

@@ -92,6 +92,22 @@ enum nand_ecc_mode {
 	NAND_ECC_ON_DIE,
 };
 
+/**
+ * enum nand_ecc_engine_type - NAND ECC engine type/provider
+ * @NAND_ECC_ENGINE_INVALID: Invalid value
+ * @NAND_ECC_ENGINE_NONE: No ECC correction
+ * @NAND_ECC_ENGINE_SOFT: Software ECC correction
+ * @NAND_ECC_ENGINE_CONTROLLER: Hardware controller ECC correction
+ * @NAND_ECC_ENGINE_ON_DIE: On chip hardware ECC correction
+ */
+enum nand_ecc_engine_type {
+	NAND_ECC_ENGINE_INVALID,
+	NAND_ECC_ENGINE_NONE,
+	NAND_ECC_ENGINE_SOFT,
+	NAND_ECC_ENGINE_CONTROLLER,
+	NAND_ECC_ENGINE_ON_DIE,
+};
+
 /**
  * enum nand_ecc_placement - NAND ECC placement
  * @NAND_ECC_PLACEMENT_FREE: The driver can decide where to put ECC bytes.