stm32x7: add support for stm32x7 serial driver

This patch adds support for stm32f7 family usart peripheral.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/serial/serial_stm32x7.h b/drivers/serial/serial_stm32x7.h
new file mode 100644
index 0000000..6190d67
--- /dev/null
+++ b/drivers/serial/serial_stm32x7.h
@@ -0,0 +1,37 @@
+/*
+ * (C) Copyright 2016
+ * Vikas Manocha, <vikas.manocha@st.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _SERIAL_STM32_X7_
+#define _SERIAL_STM32_X7_
+
+struct stm32_usart {
+	u32 cr1;
+	u32 cr2;
+	u32 cr3;
+	u32 brr;
+	u32 gtpr;
+	u32 rtor;
+	u32 rqr;
+	u32 sr;
+	u32 icr;
+	u32 rd_dr;
+	u32 tx_dr;
+};
+
+
+#define USART_CR1_RE			(1 << 2)
+#define USART_CR1_TE			(1 << 3)
+#define USART_CR1_UE			(1 << 0)
+
+#define USART_SR_FLAG_RXNE		(1 << 5)
+#define USART_SR_FLAG_TXE		(1 << 7)
+
+#define USART_BRR_F_MASK		0xFF
+#define USART_BRR_M_SHIFT		4
+#define USART_BRR_M_MASK		0xFFF0
+
+#endif