echoplayer: detect boot reason during system_init

Change-Id: I6fdc16e7476044b43e11d3f63d971bd8de860c58

firmware/reggen/stm32h743.regs

@@ -254,6 +254,20 @@ RCC @ 0x58024400 : block {
         0 LSION
     }
 
+    RSR @ 0xd0 : reg {
+        30 LPWRRSTF
+        28 WWDG1RSTF
+        26 IWDGRSTF
+        24 SFTRSTF
+        23 PORRSTF
+        22 PINRSTF
+        21 BORRSTF
+        20 D2RSTF
+        19 D1RSTF
+        17 CPURSTF
+        16 RMVF
+    }
+
     AHB1ENR @ 0xd8 : reg {
         28 USB2OTGHSULPIEN
         27 USB2OTGHSEN

firmware/target/arm/stm32/echoplayer/system-echoplayer.c

@@ -54,6 +54,8 @@
 # define F_MCO1     GPIOF_ANALOG()
 #endif
 
+enum echoplayer_boot_reason echoplayer_boot_reason = ECHOPLAYER_BOOT_REASON_NORMAL;
+
 static const struct gpio_setting gpios[] = {
     STM_DEFGPIO(GPIO_BUTTON_A,          F_INPUT_PU),
     STM_DEFGPIO(GPIO_BUTTON_B,          F_INPUT_PU),
@@ -212,6 +214,24 @@ void system_init(void)
                        pingroups, ARRAYLEN(pingroups));
     fmc_init();
 
+    /* Read & clear reset source */
+    uint32_t rsr = reg_var(RCC_RSR);
+    reg_assignf(RCC_RSR, RMVF(1));
+
+    /*
+     * Determine boot reason -- SFTRST means a software reset
+     * occurred, which may be a reboot or a power off
+     */
+    if (reg_vreadf(rsr, RCC_RSR, SFTRSTF))
+    {
+        reg_writef(RCC_APB4ENR, RTCAPBEN(1));
+
+        if (reg_readf(RTC_CR, WUTE))
+            echoplayer_boot_reason = ECHOPLAYER_BOOT_REASON_SW_REBOOT;
+        else
+            echoplayer_boot_reason = ECHOPLAYER_BOOT_REASON_SW_POWEROFF;
+    }
+
     /* Disable RTC_OUT pin */
     echoplayer_set_rtcout_mode(ECHOPLAYER_RTCOUT_DISABLED);
 }

firmware/target/arm/stm32/echoplayer/system-echoplayer.h

@@ -27,6 +27,15 @@ enum echoplayer_rtcout_mode
     ECHOPLAYER_RTCOUT_REBOOT,
 };
 
+enum echoplayer_boot_reason
+{
+    ECHOPLAYER_BOOT_REASON_NORMAL,
+    ECHOPLAYER_BOOT_REASON_SW_POWEROFF,
+    ECHOPLAYER_BOOT_REASON_SW_REBOOT,
+};
+
 void echoplayer_set_rtcout_mode(enum echoplayer_rtcout_mode mode);
 
+extern enum echoplayer_boot_reason echoplayer_boot_reason;
+
 #endif /* __SYSTEM_ECHOPLAYER_H__ */