diff options
Diffstat (limited to 'chip')
| -rw-r--r-- | chip/npcx/system.c | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/chip/npcx/system.c b/chip/npcx/system.c index ca20c7ae91..f9d4d1f584 100644 --- a/chip/npcx/system.c +++ b/chip/npcx/system.c @@ -255,6 +255,15 @@ void system_mpu_config(void) void __keep __attribute__ ((section(".lowpower_ram"))) __enter_hibernate_in_lpram(void) { + /* + * TODO (ML): Set stack pointer to upper 512B of Suspend RAM. + * Our bypass needs stack instructions but FW will turn off main ram + * later for better power consumption. + */ + asm ( + "ldr r0, =0x40001800\n" + "mov sp, r0\n" + ); /* Disable Code RAM first */ SET_BIT(NPCX_PWDWN_CTL(NPCX_PMC_PWDWN_5), NPCX_PWDWN_CTL5_MRFSH_DIS); @@ -262,8 +271,22 @@ __enter_hibernate_in_lpram(void) /* Set deep idle mode*/ NPCX_PMCSR = 0x6; + /* Enter deep idle, wake-up by GPIOxx or RTC */ - asm("wfi"); + /* + * TODO (ML): Although the probability is small, it still has chance + * to meet the same symptom that CPU's behavior is abnormal after + * wake-up from deep idle. + * Workaround: Apply the same bypass of idle but don't enable interrupt. + */ + asm ( + "push {r0-r5}\n" /* Save needed registers */ + "ldr r0, =0x40001600\n" /* Set r0 to Suspend RAM addr */ + "wfi\n" /* Wait for int to enter idle */ + "ldm r0, {r0-r5}\n" /* Add a delay after WFI */ + "pop {r0-r5}\n" /* Restore regs before enabling ints */ + "isb\n" /* Flush the cpu pipeline */ + ); /* RTC wake-up */ if (IS_BIT_SET(NPCX_WTC, NPCX_WTC_PTO)) |