drivers: flash: flexspi: Fix XIP during flash write

XIP prefetching seems to still be running, even while interrupts are
disabled. Therefore it is important to wait for the FlexSPI to be idle
before performing a write/erase operation.

Signed-off-by: Martin Stumpf <martin.stumpf@vected.de>

Author: mstumpf-vected

drivers/flash/flash_mcux_flexspi_nor.c

@@ -345,6 +345,7 @@ static int flash_flexspi_nor_write(const struct device *dev, off_t offset,
 		 * code and data accessed must reside in ram.
 		 */
 		key = irq_lock();
+		memc_flexspi_wait_bus_idle(&data->controller);
 	}
 
 	while (len) {
@@ -355,6 +356,13 @@ static int flash_flexspi_nor_write(const struct device *dev, off_t offset,
 		i = MIN(SPI_NOR_PAGE_SIZE - (offset % SPI_NOR_PAGE_SIZE), len);
 #ifdef CONFIG_FLASH_MCUX_FLEXSPI_NOR_WRITE_BUFFER
 		memcpy(nor_write_buf, src, i);
+
+		/* As memcpy could cause an XIP access,
+		 * we need to wait for XIP prefetch to be finished again
+		 */
+		if (memc_flexspi_is_running_xip(&data->controller)) {
+			memc_flexspi_wait_bus_idle(&data->controller);
+		}
 #endif
 		flash_flexspi_nor_write_enable(data);
 #ifdef CONFIG_FLASH_MCUX_FLEXSPI_NOR_WRITE_BUFFER
@@ -412,6 +420,7 @@ static int flash_flexspi_nor_erase(const struct device *dev, off_t offset,
 		 * code and data accessed must reside in ram.
 		 */
 		key = irq_lock();
+		memc_flexspi_wait_bus_idle(&data->controller);
 	}
 
 	if ((offset == 0) && (size == data->config.flashSize * KB(1))) {