On 26/10/2024 at 13:23:46 +0530, Amit Kumar Mahapatra amit.kumar-mahapatra@amd.com wrote:
This approach was suggested by Rob [1] during a discussion on Miquel's initial approach [2] to extend the MTD-CONCAT driver to support stacked memories. Define each flash node separately with its respective partitions, and add a 'concat-parts' binding to link the partitions of the two flash nodes that need to be concatenated.
flash@0 { compatible = "jedec,spi-nor" ... partitions {
Wrong indentation here and below which makes the example hard to read.
compatible = "fixed-partitions"; concat-partition = <&flash0_partition &flash1_partition>; flash0_partition: partition@0 { label = "part0_0"; reg = <0x0 0x800000>; } }} flash@1 { compatible = "jedec,spi-nor" ... partitions { compatible = "fixed-partitions"; concat-partition = <&flash0_partition &flash1_partition>; flash1_partition: partition@0 { label = "part0_1"; reg = <0x0 0x800000>; } } }
This approach has a limitation I didn't think about before: you cannot use anything else than fixed partitions as partition parser.
Based on the bindings the MTD-CONCAT driver need to be updated to create virtual mtd-concat devices.
[1] https://lore.kernel.org/all/20191118221341.GA30937@bogus/ [2] https://lore.kernel.org/all/20191113171505.26128-4-miquel.raynal@bootlin.com...
Signed-off-by: Amit Kumar Mahapatra amit.kumar-mahapatra@amd.com
.../mtd/partitions/fixed-partitions.yaml | 18 ++++++++++++++++++ .../bindings/mtd/partitions/partitions.yaml | 6 ++++++ 2 files changed, 24 insertions(+)
diff --git a/Documentation/devicetree/bindings/mtd/partitions/fixed-partitions.yaml b/Documentation/devicetree/bindings/mtd/partitions/fixed-partitions.yaml index 058253d6d889..df4ccb3dfeba 100644 --- a/Documentation/devicetree/bindings/mtd/partitions/fixed-partitions.yaml +++ b/Documentation/devicetree/bindings/mtd/partitions/fixed-partitions.yaml @@ -183,3 +183,21 @@ examples: read-only; }; };
- |
- partitions {
compatible = "fixed-partitions";#address-cells = <1>;#size-cells = <1>;
This is not strictly related but I believe we will soon have issues with these, as we will soon cross the 4GiB boundary.
concat-parts = <&part0 &part1>;part0: partition@0 {label = "flash0-part0";reg = <0x0000000 0x100000>;};part1: partition@100000 {label = "flash1-part0";reg = <0x0100000 0x200000>;};- };
diff --git a/Documentation/devicetree/bindings/mtd/partitions/partitions.yaml b/Documentation/devicetree/bindings/mtd/partitions/partitions.yaml index 1dda2c80747b..86bbd83c3f6d 100644 --- a/Documentation/devicetree/bindings/mtd/partitions/partitions.yaml +++ b/Documentation/devicetree/bindings/mtd/partitions/partitions.yaml @@ -32,6 +32,12 @@ properties: '#size-cells': enum: [1, 2]
- concat-parts:
- description: List of MTD partitions phandles that should be concatenated.
- $ref: /schemas/types.yaml#/definitions/phandle-array
- minItems: 2
- maxItems: 4
patternProperties: "^partition(-.+|@[0-9a-f]+)$": $ref: partition.yaml
Fine by me otherwise.
Thanks, Miquèl