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| author | Bobby Casey <bobbycasey@google.com> | 2021-02-22 10:42:20 -0800 |
|---|---|---|
| committer | Chromeos LUCI <chromeos-scoped@luci-project-accounts.iam.gserviceaccount.com> | 2022-07-01 00:02:59 +0000 |
| commit | b325538a3dedb7b89680e0d9385899638afd529e (patch) | |
| tree | 7f7fcb615611a7525adb9c2d59c737ebdc90e79b /core/cortex-m0 | |
| parent | 3bdfeba224ba2f64a77d13fd0079d2f185f9cc87 (diff) | |
| download | chrome-ec-b325538a3dedb7b89680e0d9385899638afd529e.tar.gz | |
cortex-m: Don't execute WFI instruction if debugging
Allowing the processor to sleep causes the debugger to stop working.
BRANCH=none
BUG=b:180144572
TEST=Monitor power per go/cros-fpmcu-source-code-docs#dragonclaw-v0_2
TEST=Icetower (pp3300_dx_mcu_mw) with no debugger connected
Idle: ~44 mW
Low Power Mode: ~5.5 mW
TEST=Icetower (pp3300_dx_mcu_mw) with debugger connected
Idle: ~75 mW
Low Power Mode: ~70 mW
TEST=Dragonclaw (pp3300_dx_mcu_mw) with no debugger connected
Idle: ~22 mW
Low Power Mode: ~1.5 mW
TEST=Dragonclaw (pp3300_dx_mcu_mw) with debugger connected
Idle: ~64 mW
Low Power Mode: ~19 mW
Signed-off-by: Bobby Casey <bobbycasey@google.com>
Change-Id: I48d58395b168dc3bb0932348cd8f5ce088fc0ac9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2713754
Commit-Queue: Tom Hughes <tomhughes@chromium.org>
Tested-by: Tom Hughes <tomhughes@chromium.org>
Reviewed-by: Tom Hughes <tomhughes@chromium.org>
Diffstat (limited to 'core/cortex-m0')
| -rw-r--r-- | core/cortex-m0/cpu.h | 9 | ||||
| -rw-r--r-- | core/cortex-m0/task.c | 2 |
2 files changed, 10 insertions, 1 deletions
diff --git a/core/cortex-m0/cpu.h b/core/cortex-m0/cpu.h index 48abf916d6..0fc2e655d4 100644 --- a/core/cortex-m0/cpu.h +++ b/core/cortex-m0/cpu.h @@ -10,6 +10,7 @@ #include <stdint.h> #include "compile_time_macros.h" +#include "debug.h" /* Macro to access 32-bit registers */ #define CPUREG(addr) (*(volatile uint32_t *)(addr)) @@ -61,4 +62,12 @@ static inline void cpu_set_interrupt_priority(uint8_t irq, uint8_t priority) (priority << prio_shift); } +static inline void cpu_enter_suspend_mode(void) +{ + /* Preserve debug sessions by not suspending when connected */ + if (!debugger_is_connected()) { + asm("wfi"); + } +} + #endif /* __CROS_EC_CPU_H */ diff --git a/core/cortex-m0/task.c b/core/cortex-m0/task.c index 5eb67c7346..4837c2dfbd 100644 --- a/core/cortex-m0/task.c +++ b/core/cortex-m0/task.c @@ -72,7 +72,7 @@ void __idle(void) * Wait for the next irq event. This stops the CPU clock * (sleep / deep sleep, depending on chip config). */ - asm("wfi"); + cpu_enter_suspend_mode(); } } #endif /* !CONFIG_LOW_POWER_IDLE */ |