/*
* OMAP4 MPUSS Low Power Entry Function
*
* The purpose of this function is to manage low power programming
* of OMAP4 MPUSS subsystem
* Paramenters:
* cpu : CPU ID
* power_state: Targetted Low power state.
*
* MPUSS Low power states
* The basic rule is that the MPUSS power domain must be at the higher or
* equal power state (state that consume more power) than the higher of the
* two CPUs. For example, it is illegal for system power to be OFF, while
* the power of one or both of the CPU is DORMANT. When an illegal state is
* entered, then the hardware behavior is unpredictable.
*
* MPUSS state for the context save
* save_state =
* 0 - Nothing lost and no need to save: MPUSS INACTIVE
* 1 - CPUx L1 and logic lost: MPUSS CSWR
* 2 - CPUx L1 and logic lost + GIC lost: MPUSS OSWR
* 3 - CPUx L1 and logic lost + GIC + L2 lost: MPUSS OFF
*/
void omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
{
unsigned int save_state, wakeup_cpu;
if (cpu > NR_CPUS)
return;
/*
* Low power state not supported on ES1.0 silicon
*/
if (omap_rev() == OMAP4430_REV_ES1_0) {
wmb();
do_wfi();
return;
}
switch (power_state) {
case PWRDM_POWER_ON:
case PWRDM_POWER_INACTIVE:
save_state = 0;
break;
case PWRDM_POWER_OFF:
save_state = 1;
setup_wakeup_routine(cpu);
save_local_timers(cpu);
break;
case PWRDM_POWER_RET:
/*
* CPUx CSWR is invalid hardware state. Additionally
* CPUx OSWR doesn't give any gain vs CPUxOFF and
* hence not supported
*/
default:
/* Invalid state */
pr_debug("Invalid CPU low power state\n");
return;
}
/*
* MPUSS book keeping should be executed by master
* CPU only which is the last CPU to go down
*/
if (cpu)
goto cpu_prepare;
/*
* Check MPUSS next state and save GIC if needed
* GIC lost during MPU OFF and OSWR
*/
pwrdm_clear_all_prev_pwrst(mpuss_pd);
if (omap4_device_off_read_next_state() &&
(omap_type() != OMAP2_DEVICE_TYPE_GP)) {
/* FIXME: Check if this can be optimised */
save_secure_all();
save_ivahd_tesla_regs();
save_l3instr_regs();
save_state = 3;
goto cpu_prepare;
}
switch (pwrdm_read_next_pwrst(mpuss_pd)) {
case PWRDM_POWER_ON:
case PWRDM_POWER_INACTIVE:
/* No need to save MPUSS context */
break;
case PWRDM_POWER_RET:
/* MPUSS OSWR, logic lost */
if (pwrdm_read_logic_retst(mpuss_pd) == PWRDM_POWER_OFF) {
if (omap_type() != OMAP2_DEVICE_TYPE_GP) {
save_gic_wakeupgen_secure();
save_l3instr_regs();
} else {
save_gic();
omap4_wakeupgen_save();
}
save_state = 2;
}
break;
case PWRDM_POWER_OFF:
/* MPUSS OFF */
if (omap_type() != OMAP2_DEVICE_TYPE_GP) {
save_secure_ram();
save_gic_wakeupgen_secure();
save_ivahd_tesla_regs();
save_l3instr_regs();
} else {
save_gic();
omap4_wakeupgen_save();
}
save_state = 3;
break;
default:
/* Fall through */
;
}
/*
* Program the CPU targeted state
*/
cpu_prepare:
clear_cpu_prev_pwrst(cpu);
if (cpu)
pwrdm_set_next_pwrst(cpu1_pwrdm, power_state);
else
pwrdm_set_next_pwrst(cpu0_pwrdm, power_state);
scu_pwrst_prepare(cpu, power_state);
/*
* Call low level routine to enter to
* targeted power state
*/
__omap4_cpu_suspend(cpu, save_state);
wakeup_cpu = hard_smp_processor_id();
/*
* Restore the CPUx and mpuss power state to ON otherwise
* CPUx power domain can transitions to programmed low power
* state while doing WFI outside the low powe code. On HS devices,
* CPUx can do WFI outside idle thread which can result in
* power domain domain transition if the previous state was
* programmed to OFF/RET.
*/
if (wakeup_cpu) {
pwrdm_set_next_pwrst(cpu1_pwrdm, PWRDM_POWER_ON);
} else {
pwrdm_set_next_pwrst(cpu0_pwrdm, PWRDM_POWER_ON);
pwrdm_set_next_pwrst(mpuss_pd, PWRDM_POWER_ON);
}
/*
* Check the CPUx previous power state
*/
if (read_cpu_prev_pwrst(wakeup_cpu) == PWRDM_POWER_OFF) {
cpu_init();
restore_mmu_table_entry();
restore_local_timers(wakeup_cpu);
}
/*
* Check MPUSS previous power state and enable
* GIC if needed.
*/
switch (pwrdm_read_prev_pwrst(mpuss_pd)) {
case PWRDM_POWER_ON:
/* No need to restore */
break;
case PWRDM_POWER_RET:
/* FIXME:
* if (pwrdm_read_prev_logic_pwrst(mpuss_pd) == PWRDM_POWER_OFF)
*/
if (omap_readl(0x4a306324) == PWRDM_POWER_OFF)
break;
case PWRDM_POWER_OFF:
/*
* Enable GIC distributor
*/
if (!wakeup_cpu) {
if ((omap_type() == OMAP2_DEVICE_TYPE_GP)
&& omap4_device_off_read_prev_state()) {
restore_gic();
omap4_wakeupgen_restore();
}
enable_gic_distributor();
if (omap_type() != OMAP2_DEVICE_TYPE_GP) {
restore_ivahd_tesla_regs();
restore_l3instr_regs();
}
}
/*
* Enable GIC cpu inrterface
*/
enable_gic_cpu_interface();
break;
default:
;
}
}
/**
* omap4_enter_lowpower: OMAP4 MPUSS Low Power Entry Function
* The purpose of this function is to manage low power programming
* of OMAP4 MPUSS subsystem
* @cpu : CPU ID
* @power_state: Low power state.
*
* MPUSS states for the context save:
* save_state =
* 0 - Nothing lost and no need to save: MPUSS INACTIVE
* 1 - CPUx L1 and logic lost: MPUSS CSWR
* 2 - CPUx L1 and logic lost + GIC lost: MPUSS OSWR
* 3 - CPUx L1 and logic lost + GIC + L2 lost: DEVICE OFF
*/
int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
{
unsigned int save_state = 0;
unsigned int wakeup_cpu;
if (omap_rev() == OMAP4430_REV_ES1_0)
return -ENXIO;
switch (power_state) {
case PWRDM_POWER_ON:
case PWRDM_POWER_INACTIVE:
save_state = 0;
break;
case PWRDM_POWER_OFF:
save_state = 1;
break;
case PWRDM_POWER_RET:
default:
/*
* CPUx CSWR is invalid hardware state. Also CPUx OSWR
* doesn't make much scense, since logic is lost and $L1
* needs to be cleaned because of coherency. This makes
* CPUx OSWR equivalent to CPUX OFF and hence not supported
*/
WARN_ON(1);
return -ENXIO;
}
pwrdm_pre_transition(NULL);
/*
* Check MPUSS next state and save interrupt controller if needed.
* In MPUSS OSWR or device OFF, interrupt controller contest is lost.
*/
mpuss_clear_prev_logic_pwrst();
if ((pwrdm_read_next_pwrst(mpuss_pd) == PWRDM_POWER_RET) &&
(pwrdm_read_logic_retst(mpuss_pd) == PWRDM_POWER_OFF))
save_state = 2;
cpu_clear_prev_logic_pwrst(cpu);
set_cpu_next_pwrst(cpu, power_state);
set_cpu_wakeup_addr(cpu, virt_to_phys(omap4_cpu_resume));
scu_pwrst_prepare(cpu, power_state);
l2x0_pwrst_prepare(cpu, save_state);
/*
* Call low level function with targeted low power state.
*/
cpu_suspend(save_state, omap4_finish_suspend);
/*
* Restore the CPUx power state to ON otherwise CPUx
* power domain can transitions to programmed low power
* state while doing WFI outside the low powe code. On
* secure devices, CPUx does WFI which can result in
* domain transition
*/
wakeup_cpu = smp_processor_id();
set_cpu_next_pwrst(wakeup_cpu, PWRDM_POWER_ON);
pwrdm_post_transition(NULL);
return 0;
}