[PATCH v3 1/3] mtd: rawnand: nand_base: support for 'NAND_IS_BOOT_MEDIUM' flag

[Arseniy Krasnov]

Based on Linux kernel:
commit f922bd798bb9 ("mtd: rawnand: add an option to specify NAND chip as a boot device")

Allow to define a NAND chip as a boot device. This can be helpful
for the selection of the ECC algorithm and strength in case the boot
ROM supports only a subset of controller provided options.

Signed-off-by: Arseniy Krasnov <avkrasnov at salutedevices.com>
Reviewed-by: Michael Trimarchi <michael at amarulasolutions.com>
---
 Changelog:                                                             
 v1 -> v2:                                                              
  * Place 'NAND_IS_BOOT_MEDIUM' according its numerical value.
 v2 -> v3:                                                              
  * Rebase on last master.

 drivers/mtd/nand/raw/nand_base.c | 3 +++
 include/linux/mtd/rawnand.h      | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 688d17ba3c..a7474574f8 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -4458,6 +4458,9 @@ static int nand_dt_init(struct mtd_info *mtd, struct nand_chip *chip, ofnode nod
 	if (ret == 16)
 		chip->options |= NAND_BUSWIDTH_16;
 
+	if (ofnode_read_bool(node, "nand-is-boot-medium"))
+		chip->options |= NAND_IS_BOOT_MEDIUM;
+
 	if (ofnode_read_bool(node, "nand-on-flash-bbt"))
 		chip->bbt_options |= NAND_BBT_USE_FLASH;
 
diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
index 4abaf4734c..0e7b5f852c 100644
--- a/include/linux/mtd/rawnand.h
+++ b/include/linux/mtd/rawnand.h
@@ -248,6 +248,11 @@ enum nand_ecc_algo {
  * kmap'ed, vmalloc'ed highmem buffers being passed from upper layers
  */
 #define NAND_USE_BOUNCE_BUFFER	0x00100000
+/*
+ * Whether the NAND chip is a boot medium. Drivers might use this information
+ * to select ECC algorithms supported by the boot ROM or similar restrictions.
+ */
+#define NAND_IS_BOOT_MEDIUM	0x00400000
 
 /*
  * Do not try to tweak the timings at runtime. This is needed when the
-- 
2.30.1