Interface between the kernel and the SoC's tickless idle code. More...

Functions
void	pbl_soc_idle (pbl_tick_t max_ticks)
	Idle the CPU.

bool	pbl_soc_tick_enable (void)
	Set up the tick interrupt.

bool	pbl_idle_confirm (void)
	Confirm that the CPU may still go to sleep.

void	pbl_idle_slept (pbl_tick_t elapsed)
	Account for a sleep during which no tick interrupt ran.

void	pbl_kernel_tick_isr (void)
	Tick interrupt body, for SoCs that own the SysTick handler.

Detailed Description

Interface between the kernel and the SoC's tickless idle code.

The SoC implements pbl_soc_idle() and pbl_soc_tick_enable(); the kernel provides the rest. A typical pbl_soc_idle():

void pbl_soc_idle(pbl_tick_t max_ticks) {
  __disable_irq();
  if (pbl_idle_confirm()) {
    prv_timer_stop_tick();
    prv_sleep_until(max_ticks);
    pbl_idle_slept(prv_ticks_elapsed());
    prv_timer_start_tick();
  }
  __enable_irq();
}

Function Documentation

◆ pbl_idle_confirm()

bool pbl_idle_confirm ( void )

Confirm that the CPU may still go to sleep.

Call with interrupts masked.

Returns: false if something became runnable since the idle thread decided to sleep.

◆ pbl_idle_slept()

void pbl_idle_slept ( pbl_tick_t elapsed )

Account for a sleep during which no tick interrupt ran.

Advances the tick count and expires the timeouts that fell due.

Parameters

elapsed Ticks slept.

◆ pbl_kernel_tick_isr()

void pbl_kernel_tick_isr ( void )

Tick interrupt body, for SoCs that own the SysTick handler.

◆ pbl_soc_idle()

void pbl_soc_idle ( pbl_tick_t max_ticks )

Idle the CPU.

Implemented by the SoC. Runs on the idle thread when nothing is runnable, only for gaps of at least two ticks; may sleep. Once interrupts are masked it must check pbl_idle_confirm() before sleeping, and report through pbl_idle_slept() any ticks that passed while the tick interrupt was off.

Parameters

max_ticks Ticks until the next timeout, PBL_TICK_FOREVER if none.

◆ pbl_soc_tick_enable()

bool pbl_soc_tick_enable ( void )

Set up the tick interrupt.

Implemented by the SoC; called when the scheduler starts. A SoC that drives the tick itself calls pbl_kernel_tick_isr() from its handler.

Returns: true if the SoC set up the tick, false to let the kernel program SysTick itself.