MIPS: Loongson64: Add support for the Loongson-2K1000 to get cpu_clock_freq

Get the fixed-clock from the CPU0 node of the device tree.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Tested-by: Ming Wang <wangming01@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/loongson64/time.c

@@ -11,9 +11,33 @@
 #include <asm/hpet.h>
 
 #include <loongson.h>
+#include <linux/clk.h>
+#include <linux/of_clk.h>
 
 void __init plat_time_init(void)
 {
+	struct clk *clk;
+	struct device_node *np;
+
+	if (loongson_sysconf.fw_interface == LOONGSON_DTB) {
+		of_clk_init(NULL);
+
+		np = of_get_cpu_node(0, NULL);
+		if (!np) {
+			pr_err("Failed to get CPU node\n");
+			return;
+		}
+
+		clk = of_clk_get(np, 0);
+		if (IS_ERR(clk)) {
+			pr_err("Failed to get CPU clock: %ld\n", PTR_ERR(clk));
+			return;
+		}
+
+		cpu_clock_freq = clk_get_rate(clk);
+		clk_put(clk);
+	}
+
 	/* setup mips r4k timer */
 	mips_hpt_frequency = cpu_clock_freq / 2;