+static void
+ao_clock_normal_switch(void)
+{
+ uint32_t cfgr;
+
+ cfgr = stm_rcc.cfgr;
+ cfgr &= ~(STM_RCC_CFGR_SW_MASK << STM_RCC_CFGR_SW);
+ cfgr |= (STM_RCC_CFGR_SW_TARGET_CLOCK << STM_RCC_CFGR_SW);
+ stm_rcc.cfgr = cfgr;
+ for (;;) {
+ uint32_t c, part, mask, val;
+
+ c = stm_rcc.cfgr;
+ mask = (STM_RCC_CFGR_SWS_MASK << STM_RCC_CFGR_SWS);
+ val = (STM_RCC_CFGR_SWS_TARGET_CLOCK << STM_RCC_CFGR_SWS);
+ part = c & mask;
+ if (part == val)
+ break;
+ }
+#if !AO_HSI && !AO_NEED_HSI
+ /* Turn off the HSI clock */
+ stm_rcc.cr &= ~(1 << STM_RCC_CR_HSION);