We use spi flash with custom driver and goal is to set it to act as secondary partition for MCUBoot.
The question is how to adapt driver to be accepted by MCUBoot, maybe there is an example on how driver should look like?
As far as I understand Nordic supports mx25r64, what files have to be produced and where to place them to enable custom driver to be accepted by MCUBoot?
The nRF91 DK which contains an mx25r64, and it will use the spi nor driver to communicate with it:
https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/drivers/flash/spi_nor.c#L10
As you can see, the spi_nor.c is located inside zephyr/drivers/flash. If you do it this way, you will be able to write/read to the spi flash using the flash API.
After adding your spi flash driver and adding your flash device to the device tree you can put the secondary partition in your external flash by doing the following:
Best regards,
Simon
Thank you for clarification, Simon.
At the moment I am struggling with this error: "zephyr\include\generated\devicetree_unfixed.h:6002:34: error: 'DT_N_S_soc_S_spi_40023000_S_at25xe081_0_P_size' undeclared here (not in a function); did you mean 'DT_N_S_soc_S_spi_40023000_S_at25xe081_0_P_reg".
I added this to my_board.dts file:
&spi2 {
status = "okay";
at25xe081: at25xe081@0 {
compatible = "at25xe081";
reg = <0>;
label = "AT25XE081";
size = <67108864>;
};
};
And in my driver wrapper I added #define DT_DRV_COMPAT at25xe081. However it seems that size property is not found when I am doing: flash_size = DT_INST_PROP(0, size) / 8. What I am missing here?
Thank you for clarification, Simon.
At the moment I am struggling with this error: "zephyr\include\generated\devicetree_unfixed.h:6002:34: error: 'DT_N_S_soc_S_spi_40023000_S_at25xe081_0_P_size' undeclared here (not in a function); did you mean 'DT_N_S_soc_S_spi_40023000_S_at25xe081_0_P_reg".
I added this to my_board.dts file:
&spi2 {
status = "okay";
at25xe081: at25xe081@0 {
compatible = "at25xe081";
reg = <0>;
label = "AT25XE081";
size = <67108864>;
};
};
And in my driver wrapper I added #define DT_DRV_COMPAT at25xe081. However it seems that size property is not found when I am doing: flash_size = DT_INST_PROP(0, size) / 8. What I am missing here?
I could not see that at25xe081 is defined in a yaml file, which needs to be done in order to use it in a dts/overlay file.
For example "jedec,spi-nor", which is used in zephyr/boards/arm/nrf9160dk_nrf9160/nrf9160dk_nrf9160_common_0_14_0.dtsi, is defined in the yaml file https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/dts/bindings/mtd/jedec%2Cspi-nor.yaml + the included files: https://github.com/nrfconnect/sdk-zephyr/blob/v3.0.99-ncs1/dts/bindings/mtd/jedec%2Cspi-nor.yaml#L12
Please create new a yaml file for at25xe081.
If it's too much work, and too many abstraction layers to add the driver to Zephyr, you could probably add it directly to your application, and maybe add it to Zephyr at a later point.
You may find these DevZone cases useful:
Best regards,
Simon
I created at25xe081.yaml with the following content:
description: |
AT25XE081 serial flash.
compatible: "at25xe081"
include: spi-device.yaml
properties:
size:
type: int
required: false
description: flash capacity in bits
And placed it in the same folder of project files, where my_board.dts resides. But still get the same error.
Also I tried to modify my_board.yaml and added include of the new file, but it did not change anything.
At the end it is important that MCUBoot builds using the new driver and I am not sure where to place files in order to accomplish that. Can these files be part of project or I have to modify SDK folder (that we want to avoid if possible).
mesh777 said:And placed it in the same folder of project files, where my_board.dts resides. But still get the same error.
Also I tried to modify my_board.yaml and added include of the new file, but it did not change anything.
Try placing it in the same folder as jedec,spi-nor.yaml, the folder zephyr/dts/bindings/mtd.
This section may be useful to learn more about compatible/bindings: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.0.2/zephyr/build/dts/bindings.html
mesh777 said:At the end it is important that MCUBoot builds using the new driver and I am not sure where to place files in order to accomplish that. Can these files be part of project or I have to modify SDK folder (that we want to avoid if possible).
I'm not sure how to add a dts bindings out of tree. However, adding it directly to Zephyr might not be a bad idea, then you could create a Pull Request at the end, making your driver a part of Zephyr upstream (and Nordic Zephyr downstream). If this is not preferable, let me know, and I can look into do this out-of-tree.
If this is not preferable, let me know, and I can look into do this out-of-tree.
Many thanks for fast response.
Yes, I think it would be better to have out-of-tree solution.
Try adding the binding to your board folder like it's done here (<board>/dts/bindings): https://github.com/nrfconnect/sdk-nrf/tree/v2.0.2/boards/arm/thingy91_nrf9160/dts/bindings.
Regarding adding your driver out-of-tree, I'm not sure if it will work by simply following this approach: https://github.com/nrfconnect/sdk-zephyr/tree/v3.0.99-ncs1/samples/application_development/out_of_tree_driver, since your driver should not be used directly, but rather through the flash.h API. The other flash drivers are put in https://github.com/nrfconnect/sdk-zephyr/tree/v3.0.99-ncs1/drivers/flash.
I'll ask internally tomorrow how to go about this.
I realized that it might be possible that the spi_nor driver actually supports the at25xe081, I'll look into this as well.