settings storage in external flash

RE: settings storage in external flash

Simonr — Tue, 11 Jul 2023 09:26:02 GMT

Hi Bilal

Sorry, a misunderstanding on my part and it seems I jumped the gun on that last reply.

If you for example NVS as the settings backend, and you want to use the partition manager, you can set the partition manager to external flash, and set the CONFIG_PM_PARTITION_REGION_NVS_STORAGE_EXTERNAL to get a partition to the external flash.

My colleague released a blog post on how to use the subsystems to for example store keys, etc. just last week, so you can give that a read as well to get a better overview of what your options are.

Best regards,

Simon

RE: settings storage in external flash

Bilal — Mon, 10 Jul 2023 16:14:33 GMT

Thanks Simon for the reply, but I don't think this answers my question.

We have already configured our external flash memory and have been using it to read and write data but I am specifically wondering if there is a way we can move the setting storage subsystem that Zephyr provides to be stored in the external flash rather than internal flash

RE: settings storage in external flash

Simonr — Mon, 10 Jul 2023 13:32:02 GMT

Due to the summer vacation period we are currently understaffed, so delayed replies must be expected. I am sorry about any inconvenience this might cause.

To set up an external flash memory, you should do as we have in our .dts board files for the MX25R6435F that is by default mounted on most of our DKs. The size would have to be halved to match 32MBm and you should double check the JEDEC ID, etc. to see that it is set up correctly, but something like this in your overlay file should be the correct setup of an external flash memory:

&qspi {
	status = "okay";
	pinctrl-0 = <&qspi_default>;
	pinctrl-1 = <&qspi_sleep>;
	pinctrl-names = "default", "sleep";
	mx25r64: mx25r6435f@0 {
		compatible = "nordic,qspi-nor";
		reg = <0>;
		/* MX25R64 supports only pp and pp4io */
		writeoc = "pp4io";
		/* MX25R64 supports all readoc options */
		readoc = "read4io";
		sck-frequency = <8000000>;
		jedec-id = [c2 28 17];
		sfdp-bfp = [
			e5 20 f1 ff  ff ff ff 03  44 eb 08 6b  08 3b 04 bb
			ee ff ff ff  ff ff 00 ff  ff ff 00 ff  0c 20 0f 52
			10 d8 00 ff  23 72 f5 00  82 ed 04 cc  44 83 68 44
			30 b0 30 b0  f7 c4 d5 5c  00 be 29 ff  f0 d0 ff ff
		];
		size = <67108864>;
		has-dpd;
		t-enter-dpd = <10000>;
		t-exit-dpd = <35000>;
	};
};

Best regards,

Simon