bsps/stm32u5-grisp-nano: New BSP

This BSP supports a custom STM32U5 based board. It uses a similar
structure like the existing STM32H7 BSP and therefore should be well
adaptable to other boards.

Co-authored-by: Christian Mauderer <christian.mauderer@embedded-brains.de>

bsps/arm/stm32u5/console/console-usart3.c

@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @ingroup RTEMSBSPsARMSTM32U5
+ *
+ * @brief STM32U5 USART3 instance.
+ */
+
+/*
+ * Copyright (C) 2024 embedded brains GmbH & Co. KG
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stm32u5/hal.h>
+
+stm32u5_uart_context stm32u5_usart3_instance = {
+  .uart =
+    { .Instance                    = USART3,
+      .Init.BaudRate               = BSP_CONSOLE_BAUD,
+      .Init.WordLength             = UART_WORDLENGTH_8B,
+      .Init.StopBits               = UART_STOPBITS_1,
+      .Init.Parity                 = UART_PARITY_NONE,
+      .Init.Mode                   = UART_MODE_TX_RX,
+      .Init.HwFlowCtl              = UART_HWCONTROL_RTS_CTS,
+      .Init.OverSampling           = UART_OVERSAMPLING_16,
+      .Init.OneBitSampling         = UART_ONE_BIT_SAMPLE_DISABLE,
+      .Init.ClockPrescaler         = UART_PRESCALER_DIV1,
+      .AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT },
+  .config = &stm32u5_usart3_config
+};