Hi everyone,

I am developing an App RoT for STM32L552 and testing the recent integrated FLIH interrupt feature, but I am missing something in the step of "Initializing the Interrupts" and "Integrating the Interrupt Handling Function".

As is described in Secure Interrupt Integration Guide, to enable an interrupt it is needed:

Binding the interrupt to a Secure Partition.
Granting the Secure Partition access permissions to the device of the interrupt.
Initializing the interrupt.
Integrating the interrupt handling function

Step 1 and 2, think that is "checked":

by adding this code to the partition manifest file.

"mmio_regions": [
{
"name": "TFM_PERIPHERAL_TIMER7",
"permission": "READ-WRITE"
}
],
"irqs": [
{
"source": "TFM_TIMER7_IRQ",
"name": "TFM_TIMER7_IRQ",
"handling": "FLIH",
}

By defining the macro with platform peripheral structure in patform/ext/target/stm/common/stm32l5xx/boards/tfm_peripherals_def.h

extern struct platform_data_t timer7
#define TFM_PERIPHERAL_TIMER7 &timer7

By assign the peripheral address in platform\ext\target\stm\common\stm32l5xx\secure\target_cfg.c

struct platform_data_t timer7 = {
__TIMER7_BASE,
__TIMER7_BASE + 0x3FF,
-1,
-1
};

By adding the peripheral name to “partition_named_mmio_list[]” in the file patform/ext/target/stm/common/stm32l5xx/boards/mmio_defs.h

const uintptr_t partition_named_mmio_list[] = {
(uintptr_t)TFM_PERIPHERAL_TIMER0,
(uintptr_t)TFM_PERIPHERAL_STD_UART,
(uintptr_t) TFM_PERIPHERAL_TIMER7,
};

And add to my partition code, the irq function, and the function to configure the timer

psa_flih_result_t tfm_timer7_irq_flih(void)
{
....
}

static void flih_test_case_1(psa_msg_t *msg) {
psa_irq_enable(TFM_TIMER7_IRQ_SIGNAL);
timer_start();
.......
timer_stop();
psa_irq_disable(TFM_TIMER7_IRQ_SIGNAL);
psa_reply(msg->handle, PSA_SUCCESS);
}

My problem, I think, is with the other two steps, 3 and 4. The TF-M documentation is not clear in these two steps.

In step 3, as is said in the documentation it is needed: i) to configure the interrupt priority; ii) to ensure that the interrupt targets the Secure State. iii) and save the interrupt information. So I suppose it goes something like this:

struct irq_t {
void *p_pt;
struct irq_load_info_t *p_ildi;
} save_tfm_timer7_irq_info;

enum tfm_hal_status_t tfm_timer7_irq_init(void *p_pt, struct irq_load_info_t *p_ildi)
{
//targetting the interrupt to S state
NVIC_ClearTargetState(TIM7_IRQn);
NVIC_SetPriority(TIM7_IRQn, 1);
NVIC_EnableIRQ(TIM7_IRQn);
//Saving the Interrupt Information
save_tfm_timer7_irq_info.p_pt = p_pt;
save_tfm_timer7_irq_info.p_ildi = p_ildi;
return TFM_HAL_SUCCESS;
}

But in which file should I put this function? And where should I call this function??

And in step 4, I also do not understand how can I meet this requirement -> "Platforms should call this entry function in the interrupt handlers defined in Vector Table with the saved information for each interrupt."

Being the function in question -> void spm_handle_interrupt(void *p_pt, struct irq_load_info_t *p_ildi).

Which file can I do this in? And how should I do this step?

Cheers,

Cristiano Rodrigues