arm: rockchip: Add RK3588 arch core support

The Rockchip RK3588 is a ARM-based SoC with quad-core Cortex-A76
and quad-core Cortex-A55 including NEON and GPU, 6TOPS NPU,
Mali-G610 MP4, HDMI Out, HDMI In, DP, eDP, MIPI DSI, MIPI CSI2,
LPDDR4/4X/5, eMMC5.1, SD3.0/MMC4.5, USB OTG 3.0, Type-C, USB 2.0,
PCIe 3.0, SATA 3, Ethernet, SDIO3.0 I2C, UART, SPI, GPIO and PWM.

Add arch core support for it.

Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/mach-rockchip/rk3588/clk_rk3588.c b/arch/arm/mach-rockchip/rk3588/clk_rk3588.c
new file mode 100644
index 0000000..3df0bf2
--- /dev/null
+++ b/arch/arm/mach-rockchip/rk3588/clk_rk3588.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * (C) Copyright 2020 Rockchip Electronics Co., Ltd.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <syscon.h>
+#include <asm/arch-rockchip/clock.h>
+#include <asm/arch-rockchip/cru_rk3588.h>
+#include <linux/err.h>
+
+int rockchip_get_clk(struct udevice **devp)
+{
+	return uclass_get_device_by_driver(UCLASS_CLK,
+			DM_DRIVER_GET(rockchip_rk3588_cru), devp);
+}
+
+void *rockchip_get_cru(void)
+{
+	struct rk3588_clk_priv *priv;
+	struct udevice *dev;
+	int ret;
+
+	ret = rockchip_get_clk(&dev);
+	if (ret)
+		return ERR_PTR(ret);
+
+	priv = dev_get_priv(dev);
+
+	return priv->cru;
+}