gd32: add gd32f4xx

Add GD32F4xx firmware library V2.1.0.

Signed-off-by: HaiLong Yang <[email protected]>

Author: cameled

GD32F4xx/CMSIS/GD/GD32F4xx/Include/gd32f4xx.h

@@ -0,0 +1,58 @@
+/*!
+    \file  system_gd32f4xx.h
+    \brief CMSIS Cortex-M4 Device Peripheral Access Layer Header File for
+           GD32F4xx Device Series
+*/
+
+/* Copyright (c) 2012 ARM LIMITED
+
+   All rights reserved.
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are met:
+   - Redistributions of source code must retain the above copyright
+     notice, this list of conditions and the following disclaimer.
+   - 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.
+   - Neither the name of ARM nor the names of its contributors may be used
+     to endorse or promote products derived from this software without
+     specific prior written permission.
+   *
+   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 COPYRIGHT HOLDERS AND 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.
+   ---------------------------------------------------------------------------*/
+
+/* This file refers the CMSIS standard, some adjustments are made according to GigaDevice chips */
+
+#ifndef SYSTEM_GD32F4XX_H
+#define SYSTEM_GD32F4XX_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+/* system clock frequency (core clock) */
+extern uint32_t SystemCoreClock;
+
+/* function declarations */
+/* initialize the system and update the SystemCoreClock variable */
+extern void SystemInit (void);
+/* update the SystemCoreClock with current core clock retrieved from cpu registers */
+extern void SystemCoreClockUpdate (void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SYSTEM_GD32F4XX_H */