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: Stefan Agner <stefan@agner.ch>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

diff --git a/Documentation/devicetree/bindings/mtd/nand.txt b/Documentation/devicetree/bindings/mtd/nand.txt
index eaef8c6..e949c77 100644 (file)
--- a/Documentation/devicetree/bindings/mtd/nand.txt
+++ b/Documentation/devicetree/bindings/mtd/nand.txt
@@ -43,6 +43,10 @@ Optional NAND chip properties:
                     This is particularly useful when only the in-band area is
                     used by the upper layers, and you want to make your NAND
                     as reliable as possible.
+- nand-is-boot-medium: 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.
+
 - nand-rb: shall contain the native Ready/Busy ids.
 
 The ECC strength and ECC step size properties define the correction capability

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index d0af534..1c633f8 100644 (file)
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -5859,6 +5859,9 @@ static int nand_dt_init(struct nand_chip *chip)
        if (of_get_nand_bus_width(dn) == 16)
                chip->options |= NAND_BUSWIDTH_16;
 
+       if (of_property_read_bool(dn, "nand-is-boot-medium"))
+               chip->options |= NAND_IS_BOOT_MEDIUM;
+
        if (of_get_nand_on_flash_bbt(dn))
                chip->bbt_options |= NAND_BBT_USE_FLASH;
 

diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
index 2d9cb7a..80aeeca 100644 (file)
--- a/include/linux/mtd/rawnand.h
+++ b/include/linux/mtd/rawnand.h
@@ -219,6 +219,12 @@ enum nand_ecc_algo {
  */
 #define NAND_WAIT_TCCS         0x00200000
 
+/*
+ * 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
+
 /* Options set by nand scan */
 /* Nand scan has allocated controller struct */
 #define NAND_CONTROLLER_ALLOC  0x80000000