flash_partitions: a flash_map alternative #71158
Conversation
zephyrbot
added
area: Devicetree Binding
Working with partitions on a flash device has been done using the flash_map subsystem. The flash_map subsystem has been limiting (e.g. zephyrproject-rtos#52395) and does not support support for flash devices that do not need an erase (non flash devices that are supported as if they are flash). The PR proposes an alternative for flash_map that supports classic flash devices, "no-erase" flash devices. Partitions can be read-only, and it is possible to provide an "override" erase-block-size. The support for "no-erase" flash devices is achieved by the definition of a "zephyr,flash-no-erase" compatible that is added to the flash device. Signed-off-by: Laczen JMS <laczenjms@gmail.com>
Add tests for the flash_partitions subsystem Signed-off-by: Laczen JMS <laczenjms@gmail.com>
|
@de-nordic please take a look |
There was a problem hiding this comment.
NAK.
First of all it incorrectly uses the compatible:
https://github.com/devicetree-org/devicetree-specification/releases/download/v0.4/devicetree-specification-v0.4.pdf
Second this keeps attaching its own api object to each partition; fash map has already been able to work with devices just by having the struct device object pointer from original device with constrains added for partition.
The layer also bypasses (skips) the fixed-partition definitions to directly access DTS definitions of them, basically skipping one layer, which is design issue. This follows lasagna anti-pattern, is hackish and does not well establish what the fixed partition object represents or is defined by.
We already have support of fixed-partition, that comes from Linuxhttps://github.com/zephyrproject-rtos/zephyr/blob/main/dts/bindings/mtd/fixed-partitions.yaml, I seen o reason to have another Zephyr specific definition for this purpose.
There is some rework needed in Flash Map, but this not good solution.
|
This pull request has been marked as stale because it has been open (more than) 60 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this pull request will automatically be closed in 14 days. Note, that you can always re-open a closed pull request at any time. |
Working with partitions on a flash device has been done using the flash_map subsystem. The flash_map subsystem has been limiting (e.g. #52395) and does not support support for flash devices that do not need an erase (non flash devices that are supported as if they are flash).
The PR proposes an alternative for flash_map that supports classic flash devices, "no-erase" flash devices. Partitions can be read-only, and it is possible to provide an "override" erase-block-size.
The support for "no-erase" flash devices is achieved by the definition of a "zephyr,flash-no-erase" compatible that is added to the flash device.
The PR is a simplified version of #70979 and only targeting flash devices.
Signed-off-by: Laczen JMS laczenjms@gmail.com