Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <61c84262-cd98-1e60-d95b-9b0492083994@gmail.com>
Date:   Sat, 15 Jul 2023 12:48:16 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.11.0
From:   Johan Jonker <jbx6244@gmail.com>
Subject: [PATCH v1 1/2] dt-bindings: mtd: nand-controller: add
 nand-skip-bbtscan and nand-no-bbm-quirk DT options
To:     miquel.raynal@bootlin.com
Cc:     richard@nod.at, vigneshr@ti.com, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org
Content-Language: en-US
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

A NAND chip can contain a different data format then the MTD framework
expects in the erase blocks for the Bad Block Table(BBT).
Result is a failed probe, while nothing wrong with the hardware.
Some MTD flags need to be set to gain access again.

Skip the automatic BBT scan with the NAND_SKIP_BBTSCAN option
so that the original content is unchanged during the driver probe.
The NAND_NO_BBM_QUIRK option allows us to erase bad blocks with
the nand_erase_nand() function and the flash_erase command.

Add nand-skip-bbtscan and nand-no-bbm-quirk Device Tree options,
so the user has the "freedom of choice" by neutral
access mode to read and write in whatever format is needed.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
---

Previous discussion:
[PATCH v3 3/3] mtd: rawnand: rockchip-nand-controller: add skipbbt option
https://lore.kernel.org/linux-mtd/1618382560.2326931.1689261435022.JavaMail.zimbra@nod.at/
---
 .../devicetree/bindings/mtd/nand-controller.yaml    | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/devicetree/bindings/mtd/nand-controller.yaml b/Documentation/devicetree/bindings/mtd/nand-controller.yaml
index f70a32d2d9d4..ca04d06a0377 100644
--- a/Documentation/devicetree/bindings/mtd/nand-controller.yaml
+++ b/Documentation/devicetree/bindings/mtd/nand-controller.yaml
@@ -103,6 +103,19 @@ patternProperties:
           the boot ROM or similar restrictions.
         $ref: /schemas/types.yaml#/definitions/flag

+      nand-no-bbm-quirk:
+        description:
+          Some controllers with pipelined ECC engines override the BBM marker with
+          data or ECC bytes, thus making bad block detection through bad block marker
+          impossible. Let's flag those chips so the core knows it shouldn't check the
+          BBM and consider all blocks good.
+        $ref: /schemas/types.yaml#/definitions/flag
+
+      nand-skip-bbtscan:
+        description:
+          This option skips the BBT scan during initialization.
+        $ref: /schemas/types.yaml#/definitions/flag
+
       nand-rb:
         description:
           Contains the native Ready/Busy IDs.
--
2.30.2