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GICV3 Interrupt Configuration (i.MX 8M Mini - ARM Cortex A53)

Hima

Hi,
We are trying to generate a timer interrupt and configure it.
So that when timer interrupt occurs it should go to the vector table and execute the timer ISR.

What we have Done :

* Generating Timer Interrupt :
1. We are using GPT2(General Purpose Timer - 2) to generate interrupt.
2. The INTID(Interrupt ID) of GPT2 interrupt is 86.
3. First timer is initialized ( clock frequency = 2MHz)
4. Then The Compare value is set to 60,000,000 (i.e 30seconds).
5. Enabling the timer (Now the timer started counting, and we are able verify this by reading the timer counter register.)

* Configuring the Interrupt in GIC:
1. The GIC used is GICV3
2. The Clock is enabled for GIC module.
3. ARE is set to 1 in GICD_CTRL, So its in GICV3 mode
4. All interrupt group are enabled in GICD_CTRL(grp0,grp1,grp1NS)
5. Waking up the GICR by clearing GICR_WAKER.ProcessorSleep to 0 and Polling GICR_WAKER.ChildrenAsleep until it reads 0
6. Enabling the interrupt in PSTATE (CPSR)
7. Setting ICC_SRE_EL3 = 1, so we can access cpu interface registers
8. Enabling all groups (grp0,grp1,grp1NS) in sytem register( cpu interface)
    in ICC_IGRPEN0_EL1,ICC_IGRPEN1_EL1,ICC_IGRPEN1_EL3
9. We are adding (INTID 86) to group0.
10.Routing INTID 86 to 0.0.0.0 (core 0 - current core)
11. Setting INTID 86 to priority to 0 (highest)
12. Set INTID 86 as level-sensitive
13. Enabling the INTID 86.

* What we are seeing:
1. Once timer is enabled,
Before elapsing 30s - The GPT2_SR(0x302e0008) value is 0x0(No compare interrupt)
                                   The GICD_ISPENDR[2](0x38880208) is 0x0 (No pending interrupt)
                                   The GICD_ISACTIVER[2](0x38880308) is 0x0 (No active interrupt)
After elapsing 30s -    The GPT2_SR(0x302e0008) value is 0x1(compare interrupt occurred)
                                   The GICD_ISPENDR[2](0x38880208) is 0x400000 (pending interrupt -INTID 86)
                                   The GICD_ISACTIVER[2](0x38880308) is 0x0 (No active interrupt)
2. The control is still in main ( verified by checking the PC)

* What we are expecting:
1.The interrupt should go to vector table and start executing the ISR.


The code for the same is given below.

Note 1 : INTID86 is SPI(Shared Peripheral Interrupt)

Note 2 : We have kept an infinite for loop in the ISR so that we can verify whether its in ISR by checking PC

Thanks for any suggestions in advance.
Bindu

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