Define partition on extern flash

[asprenger]

Hi,

I'm using NCS 2.2.0 with on a Actinius Icarus Bee board. The board has an external flash w25q64 chip and I'm trying to place the storage partition on the external flash.

I have created an overlay file like this:

/delete-node/ &storage_partition;

&w25q64 {
	partitions {
		compatible = "fixed-partitions";
		#address-cells = <1>;
		#size-cells = <1>;

		storage_partition: partition@0 {
			label = "storage";
			reg = <0x00000000 0x00040000>;
		};
	};
};

The partition does not show up when I create a list of flash areas.

Any idea how to configure this?

Thanks 

Andre

[Sigurd Hellesvik]

Hi Andre,

I tried to add your configurations to the hello world sample, and I can see the storage partition in the devicetree after the build.
How do you see that  the following?

The partition does not show up when I create a list of flash areas.

Do you have the Partition Manager enabled in your build?
Maybe this overwrites your manual devicetree partitioning?

Regards,
Sigurd Hellesvik

[asprenger]

Hi Sigurd

here is the gist of what I'm doing. I lookup the storage partition in the device tree to print some data about it. In addition I iterate over all flash areas (that is probably redundant).

#define STORAGE_PARTITION		storage_partition
#define STORAGE_PARTITION_ID	FIXED_PARTITION_ID(STORAGE_PARTITION)

void flash_area_cb(const struct flash_area *fa, void *user_data) {
	LOG_INF("device name: %s id: %d offset: 0x%lx size:%d", fa->fa_dev->name, fa->fa_id, fa->fa_off, fa->fa_size);
}

void main(void) {

	/* Lookup storage partition */
	unsigned int partition_id = STORAGE_PARTITION_ID;
	const struct flash_area *pfa;

	int rc = flash_area_open(partition_id, &pfa);
	if (rc != 0) {
		LOG_ERR("Error opening flash area %d: %d", partition_id, rc);
		return;
	}

	LOG_INF("storage_partition flash Area ID %u: %s @ 0x%x (size: %u bytes)", partition_id, 
		pfa->fa_dev->name, (unsigned int)pfa->fa_off, (unsigned int)pfa->fa_size);

	flash_area_close(pfa);


	/* List of flash areas */
	flash_area_foreach(&flash_area_cb, (void*) NULL);
}

Here is the output:

[00:00:00.546,112] <inf> main: storage_partition flash Area ID 12: flash-controller@39000 @ 0xf8000 (size: 8192 bytes)
[00:00:00.557,403] <inf> main: device name: flash-controller@39000 id: 0 offset: 0x0 size:49152
[00:00:00.566,680] <inf> main: device name: flash-controller@39000 id: 1 offset: 0xc000 size:16384
[00:00:00.576,202] <inf> main: device name: flash-controller@39000 id: 2 offset: 0x10000 size:512
[00:00:00.585,662] <inf> main: device name: flash-controller@39000 id: 3 offset: 0x10000 size:458752
[00:00:00.595,367] <inf> main: device name: flash-controller@39000 id: 4 offset: 0x10000 size:49664
[00:00:00.604,980] <inf> main: device name: flash-controller@39000 id: 5 offset: 0x10200 size:458240
[00:00:00.614,685] <inf> main: device name: flash-controller@39000 id: 6 offset: 0x10200 size:49152
[00:00:00.624,328] <inf> main: device name: flash-controller@39000 id: 7 offset: 0x1c200 size:409088
[00:00:00.634,033] <inf> main: device name: flash-controller@39000 id: 8 offset: 0x1c200 size:409088
[00:00:00.643,737] <inf> main: device name: flash-controller@39000 id: 9 offset: 0x80000 size:458752
[00:00:00.653,442] <inf> main: device name: flash-controller@39000 id: 10 offset: 0xf0000 size:32768
[00:00:00.663,177] <inf> main: device name: flash-controller@39000 id: 11 offset: 0xf8000 size:8192
[00:00:00.672,790] <inf> main: device name: flash-controller@39000 id: 12 offset: 0xf8000 size:8192
[00:00:00.682,403] <inf> main: device name: flash-controller@39000 id: 13 offset: 0xfa000 size:24576

I would expect the storage partition to use the w25q64 device but instead it used the flash-controller device.

Also I'm deleting the original storage partition in my overlay file, this does not seem to have any effect.

I can see in build/zephyr/include/generated/autoconf.h that the partition manager is enabled:

CONFIG_PARTITION_MANAGER_ENABLED 1

I'm not sure how the partition manager plays into this scenario, I need to read this up!

Thanks

Andre

[Sigurd Hellesvik]

Hi Andre,

The partition manager will handle the partitions for you.
So you can no longer use devicetree overlays for partitions.

To configure the partition manager to put for example NVS storage inside external flash, do the following:

Tell Partition Manager that external flash exists by adding the following to an devicetree overlay:

/ {
	chosen {
		nordic,pm-ext-flash = &w25q64;
	};
};

Then configure the filesystem in prj.conf:
CONFIG_PM_PARTITION_REGION_NVS_STORAGE_EXTERNAL=y

If you want to do this more custom, you can use pm_static.yml.
In that case, I recommend building with the NVS configuration first, and then copy configuration from build/partitions.yml into pm_static.yml.

Regards,
Sigurd Hellesvik

[asprenger]

Hi Sigurd,

thanks for the explanation, this makes sense for me now.

I ultimately want to place a filesystem on the external flash. I found the CONFIG_PM_PARTITION_REGION_LITTLEFS_EXTERNAL config option for this. I did not found any support for FAT but this will not matter in this case.

Thanks again for the help!

Cheers

Andre