From 3f5dc472965e6a5b8efe60e33c7b6c2d18d92008 Mon Sep 17 00:00:00 2001 From: Stefan Kerkmann Date: Mon, 11 Jul 2022 15:17:05 +0200 Subject: [Core] Use polled waiting on ChibiOS platforms that support it (#17607) * Use polled waiting on platforms that support it Due to context switching overhead waiting a very short amount of time on a sleeping thread is often not accurate and in fact not usable for timing critical usage i.e. in a driver. Thus we use polled waiting for ranges in the us range on platforms that support it instead. The fallback is the thread sleeping mechanism. This includes: * ARM platforms with CYCCNT register (ARMv7, ARMv8) this is incremented at CPU clock frequency * GD32VF103 RISC-V port with CSR_MCYCLE register this is incremented at CPU clock frequency * RP2040 ARMv6 port which uses the integrated timer peripheral which is incremented with a fixed 1MHz frequency * Use wait_us() instead of chSysPolledDelayX ...as it is powered by busy waiting now. * Add chibios waiting methods test bench --- platforms/chibios/_wait.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'platforms/chibios/_wait.h') diff --git a/platforms/chibios/_wait.h b/platforms/chibios/_wait.h index 2f36c64a2e..21cdffe11a 100644 --- a/platforms/chibios/_wait.h +++ b/platforms/chibios/_wait.h @@ -30,6 +30,11 @@ #ifdef WAIT_US_TIMER void wait_us(uint16_t duration); +#elif PORT_SUPPORTS_RT == TRUE +# define wait_us(us) \ + do { \ + chSysPolledDelayX(US2RTC(REALTIME_COUNTER_CLOCK, us)); \ + } while (0) #else # define wait_us(us) \ do { \ -- cgit v1.2.3