Hi Amit,
On 26/10/2024 at 13:23:47 +0530, Amit Kumar Mahapatra amit.kumar-mahapatra@amd.com wrote:
For implementing the proposed solution the current 'stacked-memories' & 'parallel-memories' bindings need to be updated as follow.
stacked-memories binding changes:
- Each flash will have its own flash node. This approach allows flashes of different makes and sizes to be stacked together, as each flash will be probed individually.
- Each of the flash node will have its own “reg” property that will contain its physical CS.
- Remove the size information from the bindings as it can be retrived drirectly from the flash.
- The stacked-memories DT bindings will contain the phandles of the flash nodes connected in stacked mode.
The new layer will update the mtd->size and other mtd_info parameters after both the flashes are probed and will call mtd_device_register with the combined information.
spi@0 { ... flash@0 { compatible = "jedec,spi-nor" reg = <0x00>; stacked-memories = <&flash@0 &flash@1>; spi-max-frequency = <50000000>; ... partitions { 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" reg = <0x01>; stacked-memories = <&flash@0 &flash@1>; spi-max-frequency = <50000000>; ... partitions {
Same comment as before here.
compatible = "fixed-partitions"; concat-partition = <&flash0_partition &flash1_partition>; flash1_partition: partition@0 { label = "part0_1"; reg = <0x0 0x800000>; } } }}
parallel-memories binding changes:
- Remove the size information from the bindings and change the type to boolen.
- Each flash connected in parallel mode should be identical and will have one flash node for both the flash devices.
- The “reg” prop will contain the physical CS number for both the connected flashes.
The new layer will double the mtd-> size and register it with the mtd layer.
Not so sure about that, you'll need a new mtd device to capture the whole device. But this is implementation related, not relevant for binding.
spi@1 { ... flash@3 { compatible = "jedec,spi-nor" reg = <0x00 0x01>; paralle-memories ;
Please fix the typos and the spacing (same above).
spi-max-frequency = <50000000>; ... partitions { compatible = "fixed-partitions"; flash0_partition: partition@0 { label = "part0_0"; reg = <0x0 0x800000>; } } }}
Signed-off-by: Amit Kumar Mahapatra amit.kumar-mahapatra@amd.com
.../bindings/spi/spi-controller.yaml | 23 +++++++++++++++++-- .../bindings/spi/spi-peripheral-props.yaml | 9 +++----- 2 files changed, 24 insertions(+), 8 deletions(-)
diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml index 093150c0cb87..2d300f98dd72 100644 --- a/Documentation/devicetree/bindings/spi/spi-controller.yaml +++ b/Documentation/devicetree/bindings/spi/spi-controller.yaml @@ -185,7 +185,26 @@ examples: flash@2 { compatible = "jedec,spi-nor"; spi-max-frequency = <50000000>;
reg = <2>, <3>;stacked-memories = /bits/ 64 <0x10000000 0x10000000>;
reg = <2>;stacked-memories = <&flash0 &flash1>; };
I'm sorry but this is not what you've talked about in this series. Either you have flash0 and flash1 and use the stacked-memories property in both of them (which is what you described) or you create a third virtual device which points to two other flashes. This example allows for an easier use of the partitions mechanism on top of a virtual mtd device but, heh, you're now describing a virtual mtd device, which is not a physical device as it "should" be.
Thanks, Miquèl