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/start/stm32u5-config-rtc.c

@@ -0,0 +1,143 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @ingroup RTEMSBSPsARMSTM32U5
+ *
+ * @brief Implementation of the RTC driver for the STM32U5
+ */
+
+/*
+ * 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.
+ */
+
+#include <bsp.h>
+#include <bsp/fatal.h>
+#include <bsp/start.h>
+#include <libchip/rtc.h>
+#include <rtems/rtems/clockimpl.h>
+#include <rtems/score/todimpl.h>
+#include <stm32u5/hal.h>
+
+RTC_HandleTypeDef hrtc  = { 0 };
+RTC_TimeTypeDef   sTime = { 0 };
+RTC_DateTypeDef   sDate = { 0 };
+
+void stm32u5_rtc_get_time( rtems_time_of_day *tod )
+{
+  if ( HAL_RTC_GetTime( &hrtc, &sTime, RTC_FORMAT_BIN ) != HAL_OK ) {
+    bsp_fatal( STM32U5_FATAL_RTC );
+  }
+
+  if ( HAL_RTC_GetDate( &hrtc, &sDate, RTC_FORMAT_BIN ) != HAL_OK ) {
+    bsp_fatal( STM32U5_FATAL_RTC );
+  }
+
+  tod->ticks  = 0;
+  tod->second = sTime.Seconds;
+  tod->minute = sTime.Minutes;
+  tod->hour   = sTime.Hours;
+  tod->day    = sDate.Date;
+  tod->month  = sDate.Month;
+  tod->year   = TOD_BASE_YEAR + sDate.Year;
+}
+
+static void stm32u5_rtc_device_initialize( int minor )
+{
+  hrtc.Instance            = RTC;
+  hrtc.Init.HourFormat     = RTC_HOURFORMAT_24;
+  hrtc.Init.AsynchPrediv   = 127;
+  hrtc.Init.SynchPrediv    = 255;
+  hrtc.Init.OutPut         = RTC_OUTPUT_DISABLE;
+  hrtc.Init.OutPutRemap    = RTC_OUTPUT_REMAP_NONE;
+  hrtc.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
+  hrtc.Init.OutPutType     = RTC_OUTPUT_TYPE_OPENDRAIN;
+  hrtc.Init.OutPutPullUp   = RTC_OUTPUT_PULLUP_NONE;
+  hrtc.Init.BinMode        = RTC_BINARY_MIX;
+  if ( HAL_RTC_Init( &hrtc ) != HAL_OK ) {
+    bsp_fatal( STM32U5_FATAL_RTC );
+  }
+}
+
+static int stm32u5_rtc_device_get_time( int minor, rtems_time_of_day *tod )
+{
+  stm32u5_rtc_get_time( tod );
+
+  return 0;
+}
+
+static int stm32u5_rtc_device_set_time(
+  int                      minor,
+  const rtems_time_of_day *tod
+)
+{
+  sTime.Hours   = (uint8_t) tod->hour;
+  sTime.Minutes = (uint8_t) tod->minute;
+  sTime.Seconds = (uint8_t) tod->second;
+  sDate.Date    = (uint8_t) tod->day;
+  sDate.Month   = (uint8_t) tod->month;
+  sDate.Year    = (uint8_t) tod->year - TOD_BASE_YEAR;
+
+  if ( HAL_RTC_SetTime( &hrtc, &sTime, RTC_FORMAT_BIN ) != HAL_OK ) {
+    bsp_fatal( STM32U5_FATAL_RTC );
+  }
+
+  if ( HAL_RTC_SetDate( &hrtc, &sDate, RTC_FORMAT_BIN ) != HAL_OK ) {
+    bsp_fatal( STM32U5_FATAL_RTC );
+  }
+
+  return 0;
+}
+
+static bool stm32u5_rtc_device_probe( int minor )
+{
+  return true;
+}
+
+const rtc_fns stm32u5_rtc_device_ops = {
+  .deviceInitialize = stm32u5_rtc_device_initialize,
+  .deviceGetTime    = stm32u5_rtc_device_get_time,
+  .deviceSetTime    = stm32u5_rtc_device_set_time
+};
+
+rtc_tbl RTC_Table[] = {
+  { .sDeviceName = "/dev/rtc",
+    .deviceType  = RTC_CUSTOM,
+    .pDeviceFns  = &stm32u5_rtc_device_ops,
+    .deviceProbe = stm32u5_rtc_device_probe }
+};
+
+void BSP_START_TEXT_SECTION HAL_RTC_MspInit( RTC_HandleTypeDef *hrtc )
+{
+  /* Enable peripheral clocks and battery backup. */
+  __HAL_RCC_PWR_CLK_ENABLE();
+  HAL_PWR_EnableBkUpAccess();
+  __HAL_RCC_RTC_CONFIG( RCC_RTCCLKSOURCE_LSE );
+  __HAL_RCC_RTC_ENABLE();
+  __HAL_RCC_RTCAPB_CLK_ENABLE();
+  __HAL_RCC_RTCAPB_CLKAM_ENABLE();
+}
+
+size_t RTC_Count = RTEMS_ARRAY_SIZE( RTC_Table );