lantiq: kernel: xway-nand: Fix setting on-die ECC engines in dts

This backports a fix proposed for upstream kernel to fix overwriting
the NAND ECC engine in device tree.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

2 files changed, 70 insertions, 2 deletions

diff --git a/target/linux/lantiq/patches-5.10/0016-mtd-rawnand-xway-Keep-the-driver-compatible-with-on-.patch b/target/linux/lantiq/patches-5.10/0016-mtd-rawnand-xway-Keep-the-driver-compatible-with-on-.patch
new file mode 100644
index 0000000000..4f23cc94d7
--- /dev/null
+++ b/target/linux/lantiq/patches-5.10/0016-mtd-rawnand-xway-Keep-the-driver-compatible-with-on-.patch
@@ -0,0 +1,68 @@
+From ae9a2ac4d283b2925a97523a05ea024499329c16 Mon Sep 17 00:00:00 2001
+From: Miquel Raynal <miquel.raynal@bootlin.com>
+Date: Wed, 29 Sep 2021 00:22:58 +0200
+Subject: [PATCH] mtd: rawnand: xway: Keep the driver compatible with on-die
+ ECC engines
+
+Following the introduction of the generic ECC engine infrastructure, it
+was necessary to reorganize the code and move the ECC configuration in
+the ->attach_chip() hook. Failing to do that properly lead to a first
+series of fixes supposed to stabilize the situation. Unfortunately, this
+only fixed the use of software ECC engines, preventing any other kind of
+engine to be used, including on-die ones.
+
+It is now time to (finally) fix the situation by ensuring that we still
+provide a default (eg. software ECC) but will still support different
+ECC engines such as on-die ECC engines if properly described in the
+device tree.
+
+There are no changes needed on the core side in order to do this, but we
+just need to leverage the logic there which allows:
+1- a subsystem default (set to Host engines in the raw NAND world)
+2- a driver specific default (here set to software ECC engines)
+3- any type of engine requested by the user (ie. described in the DT)
+
+As the raw NAND subsystem has not yet been fully converted to the ECC
+engine infrastructure, in order to provide a default ECC engine for this
+driver we need to set chip->ecc.engine_type *before* calling
+nand_scan(). During the initialization step, the core will consider this
+entry as the default engine for this driver. This value may of course
+be overloaded by the user if the usual DT properties are provided.
+
+Fixes: d525914b5bd8 ("mtd: rawnand: xway: Move the ECC initialization to ->attach_chip()")
+Cc: stable@vger.kernel.org
+Cc: Jan Hoffmann <jan@3e8.eu>
+Cc: Kestrel seventyfour <kestrelseventyfour@gmail.com>
+Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
+---
+ drivers/mtd/nand/raw/xway_nand.c | 12 +++++++++---
+ 1 file changed, 9 insertions(+), 3 deletions(-)
+
+--- a/drivers/mtd/nand/raw/xway_nand.c
++++ b/drivers/mtd/nand/raw/xway_nand.c
+@@ -148,9 +148,8 @@ static void xway_write_buf(struct nand_c
+ 
+ static int xway_attach_chip(struct nand_chip *chip)
+ {
+-	chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
+-
+-	if (chip->ecc.algo == NAND_ECC_ALGO_UNKNOWN)
++	if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_SOFT &&
++	    chip->ecc.algo == NAND_ECC_ALGO_UNKNOWN)
+ 		chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
+ 
+ 	return 0;
+@@ -219,6 +218,13 @@ static int xway_nand_probe(struct platfo
+ 		    | NAND_CON_SE_P | NAND_CON_WP_P | NAND_CON_PRE_P
+ 		    | cs_flag, EBU_NAND_CON);
+ 
++	/*
++	 * This driver assumes that the default ECC engine should be TYPE_SOFT.
++	 * Set ->engine_type before registering the NAND devices in order to
++	 * provide a driver specific default value.
++	 */
++	data->chip.ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
++
+ 	/* Scan to find existence of the device */
+ 	err = nand_scan(&data->chip, 1);
+ 	if (err)
diff --git a/target/linux/lantiq/patches-5.10/0018-MTD-nand-lots-of-xrx200-fixes.patch b/target/linux/lantiq/patches-5.10/0018-MTD-nand-lots-of-xrx200-fixes.patch
index d8393f352a..35f656da6e 100644
--- a/target/linux/lantiq/patches-5.10/0018-MTD-nand-lots-of-xrx200-fixes.patch
+++ b/target/linux/lantiq/patches-5.10/0018-MTD-nand-lots-of-xrx200-fixes.patch
@@ -95,7 +95,7 @@ Signed-off-by: John Crispin <blogic@openwrt.org>
  }
  
  static int xway_dev_ready(struct nand_chip *chip)
-@@ -171,6 +224,7 @@ static int xway_nand_probe(struct platfo
+@@ -170,6 +223,7 @@ static int xway_nand_probe(struct platfo
  	int err;
  	u32 cs;
  	u32 cs_flag = 0;
@@ -103,7 +103,7 @@ Signed-off-by: John Crispin <blogic@openwrt.org>
  
  	/* Allocate memory for the device structure (and zero it) */
  	data = devm_kzalloc(&pdev->dev, sizeof(struct xway_nand_data),
-@@ -207,6 +261,15 @@ static int xway_nand_probe(struct platfo
+@@ -206,6 +260,15 @@ static int xway_nand_probe(struct platfo
  	if (!err && cs == 1)
  		cs_flag = NAND_CON_IN_CS1 | NAND_CON_OUT_CS1;