HW Interrupts

Table of Contents

• Features Supported
• Features NOT Supported
• Important Usage Guidelines
• Example Usage
• API

Attention

See also FreeRTOS, NO RTOS for list of CPU specific supported and unsupported features.

Features Supported

• Register a interrupt callback to a specific CPU number
• Ability to pass user specific argument to the interrupt callback
• Enable, disable, restore and clear specific CPU interrupts
• Enable, disable, restore global CPU interrupt
• For ARM R5,
  • Ability to specify interrupt as FIQ or IRQ, level or pulse
  • Ability to specify interrupt priority

Features NOT Supported

See also FreeRTOS, NO RTOS for list of unsupported features.

Important Usage Guidelines

• For ARM R5,
  • TI VIM is the interrupt controller that is supported.
  • HwiP_disable, HwiP_restore, HwiP_enable only affect state of IRQ. FIQ state is not changed
  • Refer ARMv7-R Architecture reference manual and SOC TRM for more details.
• On AM62AX,

  CPU type	Valid interrupt numbers	Valid interrupt priorities
  R5F	0 .. 511	0 (highest) .. 15 (lowest)

• On C75,
  • The C75 CPU supports 64 interrupts.
  • The CLEC event ID can be mapped to any of C75 interrupts.
  • If you are configuring software interrupt, then set eventId to HWIP_INVALID_EVENT_ID.
  • While mapping CLEC event ID to interrupt number, refer the below table and avoid overlapping interrupts.

    Module	Interrupt number used
    TIMER	8 .. 15
    I2C	16 .. 20
    UART	22 .. 30
    UDMA	32 .. 48
    MCASP	53 .. 58
    IPC	59 .. 62

Example Usage

Include the below file to access the APIs,

#include <stdio.h>
#include <kernel/dpl/HwiP.h>

Example ISR,

void myISR(void *args)
{
    /* my ISR */
}

Example to register a ISR for CPU interrupt 10,

    HwiP_Params hwiParams;
    HwiP_Object hwiObj;
 
    HwiP_Params_init(&hwiParams);
    /* for R5F, interrupt #10 at VIM */
    hwiParams.intNum = 10;
    /* for M4F, external interrupt #10 at NVIC is
       16 internal interrupts + external interrupt number at NVIC
       i.e hwiParams.intNum = 16 + 10;
     */
    /* for C75, CLEC event ID can be mapped to any of the internal interrupt number
       set both event ID and interrupt number
       to configure harware clec event #10
           hwiParams.eventId = 10;
           hwiParams.intNum = 31;
       to configure software interrupt #31
           hwiParams.eventId = HWIP_INVALID_EVENT_ID;
           hwiParams.intNum = 31;
 
     */
    hwiParams.callback = myISR;
    hwiParams.args = NULL;
 
    HwiP_construct(&hwiObj, &hwiParams);

Example to disable and restore interrupts across a crtical section

    uintptr_t oldIntState;
 
    oldIntState = HwiP_disable();
 
    /* critical section */
 
    HwiP_restore(oldIntState);

API

APIs for HW Interrupts