non blocking flash on f7 dual bank 2MB (#2749)

* f7 dual bank flash

* only start thread if necessary

firmware/config/stm32f7ems/efifeatures.h

@@ -55,3 +55,6 @@
 
 #undef ENABLE_PERF_TRACE
 #define ENABLE_PERF_TRACE TRUE
+
+// F7 may have dual bank, so flash on its own (low priority) thread so as to not block any other operations
+#define EFI_FLASH_WRITE_THREAD TRUE

firmware/controllers/flash_main.cpp

@@ -63,8 +63,10 @@ void setNeedToWriteConfiguration(void) {
 	needToWriteConfiguration = true;
 
 #if EFI_FLASH_WRITE_THREAD
-	// Signal the flash writer thread to wake up and write at its leisure
-	flashWriteSemaphore.signal();
+	if (allowFlashWhileRunning()) {
+		// Signal the flash writer thread to wake up and write at its leisure
+		flashWriteSemaphore.signal();
+	}
 #endif // EFI_FLASH_WRITE_THREAD
 }
 
@@ -73,15 +75,13 @@ bool getNeedToWriteConfiguration(void) {
 }
 
 void writeToFlashIfPending() {
-// with a flash write thread, the schedule happens directly from
-// setNeedToWriteConfiguration, so there's nothing to do here
-#if !EFI_FLASH_WRITE_THREAD
-	if (!getNeedToWriteConfiguration()) {
+	// with a flash write thread, the schedule happens directly from
+	// setNeedToWriteConfiguration, so there's nothing to do here
+	if (allowFlashWhileRunning() || !getNeedToWriteConfiguration()) {
 		return;
 	}
 
 	writeToFlashNow();
-#endif
 }
 
 // Erase and write a copy of the configuration at the specified address
@@ -254,7 +254,9 @@ void initFlash() {
 	addConsoleAction("rewriteconfig", rewriteConfig);
 
 #if EFI_FLASH_WRITE_THREAD
-	chThdCreateStatic(flashWriteStack, sizeof(flashWriteStack), PRIO_FLASH_WRITE, flashWriteThread, nullptr);
+	if (allowFlashWhileRunning()) {
+		chThdCreateStatic(flashWriteStack, sizeof(flashWriteStack), PRIO_FLASH_WRITE, flashWriteThread, nullptr);
+	}
 #endif
 }
 

firmware/hw_layer/ports/cypress/mpu_util.cpp

@@ -238,6 +238,10 @@ CANDriver * detectCanDevice(brain_pin_e pinRx, brain_pin_e pinTx) {
 
 #endif /* EFI_CAN_SUPPORT */
 
+bool allowFlashWhileRunning() {
+	return false;
+}
+
 size_t flashSectorSize(flashsector_t sector) {
 	// sectors 0..11 are the 1st memory bank (1Mb), and 12..23 are the 2nd (the same structure).
 	if (sector <= 3 || (sector >= 12 && sector <= 15))

firmware/hw_layer/ports/kinetis/mpu_util.cpp

@@ -230,6 +230,10 @@ CANDriver * detectCanDevice(brain_pin_e pinRx, brain_pin_e pinTx) {
 
 #endif /* EFI_CAN_SUPPORT */
 
+bool allowFlashWhileRunning() {
+	return false;
+}
+
 size_t flashSectorSize(flashsector_t sector) {
 	// sectors 0..11 are the 1st memory bank (1Mb), and 12..23 are the 2nd (the same structure).
 	if (sector <= 3 || (sector >= 12 && sector <= 15))

firmware/hw_layer/ports/mpu_util.h

@@ -9,6 +9,7 @@
 // Base MCU
 void baseMCUInit(void);
 void jump_to_bootloader();
+bool allowFlashWhileRunning();
 
 // ADC
 #if HAL_USE_ADC

firmware/hw_layer/ports/stm32/stm32f4/mpu_util.cpp

@@ -7,6 +7,11 @@
 
 #include "flash_int.h"
 
+bool allowFlashWhileRunning() {
+	// Never allow flash while running on F4, dual bank not implemented.
+	return false;
+}
+
 size_t flashSectorSize(flashsector_t sector) {
 	// sectors 0..11 are the 1st memory bank (1Mb), and 12..23 are the 2nd (the same structure).
 	if (sector <= 3 || (sector >= 12 && sector <= 15))

firmware/hw_layer/ports/stm32/stm32f7/mpu_util.cpp

@@ -49,6 +49,11 @@ static DeviceType determineDevice() {
 	return DeviceType::Unknown;
 }
 
+bool allowFlashWhileRunning() {
+	// Allow flash-while-running if dual bank mode is enabled, and we're a 2MB device (ie, no code located in second bank)
+	return determineDevice() == DeviceType::DualBank2MB;
+}
+
 // See ST AN4826
 size_t flashSectorSize(flashsector_t sector) {
 	// 1MB devices have 8 sectors per bank

firmware/hw_layer/ports/stm32/stm32h7/mpu_util.cpp

@@ -7,6 +7,11 @@
 
 #include "flash_int.h"
 
+bool allowFlashWhileRunning() {
+	// We only support dual bank H7, so always allow flash while running.
+	return true;
+}
+
 size_t flashSectorSize(flashsector_t sector) {
 	// All sectors on H7 are 128k
 	return 128 * 1024;