stm32l4: add initial soc support for stm32l4

Add the initial SoC support for the STM32L4XX family. The code was
tested on STM32L476RG, but should work on any STM32L4XX currently
available.

This implementation was inspired by the stm32f1x implementation.

Change-Id: Id6670bce0c423617284e8467a9c461531f948e0f
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>

arch/arm/soc/st_stm32/stm32l4/soc.h

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2016 Open-RnD Sp. z o.o.
+ * Copyright (c) 2016 BayLibre, SAS
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @file SoC configuration macros for the STM32F103 family processors.
+ *
+ * Based on reference manual:
+ *   STM32L4x1, STM32L4x2, STM32L431xx STM32L443xx STM32L433xx, STM32L4x5,
+ *   STM32l4x6 advanced ARM ® -based 32-bit MCUs
+ *
+ * Chapter 2.2.2: Memory map and register boundary addresses
+ */
+
+
+#ifndef _STM32L4X_SOC_H_
+#define _STM32L4X_SOC_H_
+
+#ifndef _ASMLANGUAGE
+
+#include <autoconf.h>
+#include <device.h>
+#include <stm32l4xx.h>
+
+#define GPIO_REG_SIZE         0x400
+/* base address for where GPIO registers start */
+#define GPIO_PORTS_BASE       (GPIOA_BASE)
+
+#include "soc_irq.h"
+
+#ifdef CONFIG_SERIAL_HAS_DRIVER
+#include <stm32l4xx_ll_usart.h>
+#endif
+
+#endif /* !_ASMLANGUAGE */
+
+#endif /* _STM32L4X_SOC_H_ */