dt-bindings: mtd: amlogic,meson-nand: support fields for boot ROM code

Boot ROM code on Meson requires that some pages on NAND must be written
in special mode: "short" ECC mode where each block is 384 bytes and
scrambling mode is on. Such pages are located on the chip in the
following way (for example):

[ p0 ][ p1 ][ p2 ][ p3 ][ p4 ][ p5 ][ p6 ][ p7 ] ... [ pN ]
  ^           ^           ^           ^

pX is page number "X". "^" means "special" page used by boot ROM - e.g.
every 2nd page in the range of [0, 7]. Step (2 in example is set by
'amlogic,boot-page-step' field. Last page in range (7 in example) is
set by 'amlogic,boot-pages' field.

Signed-off-by: Arseniy Krasnov <[email protected]>
Reviewed-by: Rob Herring (Arm) <[email protected]>
Signed-off-by: Miquel Raynal <[email protected]>
Link: https://lore.kernel.org/linux-mtd/[email protected]

Author: Arseniy Krasnov

Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml

@@ -64,11 +64,29 @@ patternProperties:
         items:
           maximum: 0
 
+      amlogic,boot-pages:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description:
+          Number of pages starting from offset 0, where a special ECC
+          configuration must be used because it is accessed by the ROM
+          code. This ECC configuration uses 384 bytes data blocks.
+          Also scrambling mode is enabled for such pages.
+
+      amlogic,boot-page-step:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description:
+          Interval between pages, accessed by the ROM code. For example
+          we have 8 pages [0, 7]. Pages 0,2,4,6 are accessed by the
+          ROM code, so this field will be 2 (e.g. every 2nd page). Rest
+          of pages - 1,3,5,7 are read/written without this mode.
+
     unevaluatedProperties: false
 
     dependencies:
       nand-ecc-strength: [nand-ecc-step-size]
       nand-ecc-step-size: [nand-ecc-strength]
+      amlogic,boot-pages: [nand-is-boot-medium, "amlogic,boot-page-step"]
+      amlogic,boot-page-step: [nand-is-boot-medium, "amlogic,boot-pages"]
 
 
 required: