riscv: cpu: fu740: Add support for cpu fu740

Add SiFive fu740 cpu to support RISC-V arch

Signed-off-by: Green Wan <green.wan@sifive.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/riscv/include/asm/arch-fu740/gpio.h b/arch/riscv/include/asm/arch-fu740/gpio.h
new file mode 100644
index 0000000..908e2e5
--- /dev/null
+++ b/arch/riscv/include/asm/arch-fu740/gpio.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2020-2021 SiFive, Inc.
+ */
+
+#ifndef _GPIO_SIFIVE_H
+#define _GPIO_SIFIVE_H
+
+#define GPIO_INPUT_VAL	0x00
+#define GPIO_INPUT_EN	0x04
+#define GPIO_OUTPUT_EN	0x08
+#define GPIO_OUTPUT_VAL	0x0C
+#define GPIO_RISE_IE	0x18
+#define GPIO_RISE_IP	0x1C
+#define GPIO_FALL_IE	0x20
+#define GPIO_FALL_IP	0x24
+#define GPIO_HIGH_IE	0x28
+#define GPIO_HIGH_IP	0x2C
+#define GPIO_LOW_IE	0x30
+#define GPIO_LOW_IP	0x34
+#define GPIO_OUTPUT_XOR	0x40
+
+#define NR_GPIOS	16
+
+enum gpio_state {
+	LOW,
+	HIGH
+};
+
+/* Details about a GPIO bank */
+struct sifive_gpio_plat {
+	void *base;     /* address of registers in physical memory */
+};
+
+#define SIFIVE_GENERIC_GPIO_NR(port, index) \
+		(((port) * NR_GPIOS) + ((index) & (NR_GPIOS - 1)))
+
+#endif /* _GPIO_SIFIVE_H */