[opensbi] create opensbi from T-Head official:

repo: https://github.com/T-head-Semi/opensbi
	commit: 89182b257c8798e15e4c685c1af0c2862d528d2a

Change-Id: I7b39d66729e0108661a6f4c9e28acbdb303684ea

opensbi/lib/utils/serial/shakti-uart.c

@@ -0,0 +1,56 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Vijai Kumar K <vijai@behindbytes.com>
+ */
+
+#include <sbi/riscv_io.h>
+#include <sbi/sbi_console.h>
+#include <sbi_utils/serial/shakti-uart.h>
+
+#define REG_BAUD	0x00
+#define REG_TX		0x04
+#define REG_RX		0x08
+#define REG_STATUS	0x0C
+#define REG_DELAY	0x10
+#define REG_CONTROL	0x14
+#define REG_INT_EN	0x18
+#define REG_IQ_CYCLES	0x1C
+#define REG_RX_THRES	0x20
+
+#define UART_TX_FULL  0x2
+#define UART_RX_FULL  0x8
+
+static volatile void *uart_base;
+
+static void shakti_uart_putc(char ch)
+{
+	while((readw(uart_base + REG_STATUS) & UART_TX_FULL))
+		;
+	writeb(ch, uart_base + REG_TX);
+}
+
+static int shakti_uart_getc(void)
+{
+	u16 status = readw(uart_base + REG_STATUS);
+	if (status & UART_RX_FULL)
+		return readb(uart_base + REG_RX);
+	return -1;
+}
+
+static struct sbi_console_device shakti_console = {
+	.name = "shakti_uart",
+	.console_putc = shakti_uart_putc,
+	.console_getc = shakti_uart_getc
+};
+
+int shakti_uart_init(unsigned long base, u32 in_freq, u32 baudrate)
+{
+	uart_base = (volatile void *)base;
+	u16 baud = (u16)(in_freq/(16 * baudrate));
+	writew(baud, uart_base + REG_BAUD);
+
+	sbi_console_set_device(&shakti_console);
+
+	return 0;
+}