Accessing timers from the secure world/TFM custom partition?

RE: Accessing timers from the secure world/TFM custom partition?

Hieu — Fri, 05 Jul 2024 16:04:11 GMT

Hi gdl,

I am glad to know things are working.

[quote user="gdl"]I'm trying to make some performance measurements. But i wouldn't be able to use the timing-features of zephyr in the custom secure partition/TFM or could i (as the secure world doesn't use zephyr if i didn't misunderstand it)?[/quote]

I don't think you made any misunderstanding. I am a novice in this topic myself and misunderstood things.

On this note, I want to add that there is also the RTC peripheral, which has much lower resolution and accuracy, but also much lower current consumption. However, as you are only making measurements during development, I assume power efficiency isn't much of a concern.

[quote user="gdl"]Also is there any way to use one timer (or sth similar) from both the non-secure and the secure world?[/quote]

I don't think so. That would violate the principle of isolation, wouldn't it?

RE: Accessing timers from the secure world/TFM custom partition?

gdl — Thu, 04 Jul 2024 15:39:37 GMT

Hey Hieu
Many Thanks. I didn't correctly fully configure the yaml and it seems to work now.

[quote userid="9456" url="~/f/nordic-q-a/112638/accessing-timers-from-the-secure-world-tfm-custom-partition/491844"]As you mentioned that you want to do most things in the secure domain, I would like to remind you that doing that is not necessarily more secured, and the modem can only be accessed from the non-secure domain.[/quote]

Sry i said that unclear. Later somebody else will write the extensive actual code for the non-secure world, but for now development is mainly about the secure-world.

[quote userid="9456" url="~/f/nordic-q-a/112638/accessing-timers-from-the-secure-world-tfm-custom-partition/491844"]Also, depends on what you are trying to implement, you might not need a TIMER peripheral, and might be able to use something simpler, such as the timing features in the Zephyr Kernel.[/quote]

I'm trying to make some performance measurements. But i wouldn't be able to use the timing-features of zephyr in the custom secure partition/TFM or could i (as the secure world doesn't use zephyr if i didn't misunderstand it)?

Also is there any way to use one timer (or sth similar) from both the non-secure and the secure world?

RE: Accessing timers from the secure world/TFM custom partition?

Hieu — Tue, 02 Jul 2024 12:49:54 GMT

Hi gdl,

Configuring a peripheral to be used in the secure domain is demonstrated in the TF-M secure peripheral partition sample. Have you taken a look at it yet?

Also, depends on what you are trying to implement, you might not need a TIMER peripheral, and might be able to use something simpler, such as the timing features in the Zephyr Kernel.

As you mentioned that you want to do most things in the secure domain, I would like to remind you that doing that is not necessarily more secured, and the modem can only be accessed from the non-secure domain.

Hieu