v4.19.13 snapshot.
diff --git a/drivers/cpufreq/loongson2_cpufreq.c b/drivers/cpufreq/loongson2_cpufreq.c
new file mode 100644
index 0000000..da34469
--- /dev/null
+++ b/drivers/cpufreq/loongson2_cpufreq.c
@@ -0,0 +1,196 @@
+/*
+ * Cpufreq driver for the loongson-2 processors
+ *
+ * The 2E revision of loongson processor not support this feature.
+ *
+ * Copyright (C) 2006 - 2008 Lemote Inc. & Institute of Computing Technology
+ * Author: Yanhua, yanh@lemote.com
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cpufreq.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/sched.h> /* set_cpus_allowed() */
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+
+#include <asm/clock.h>
+#include <asm/idle.h>
+
+#include <asm/mach-loongson64/loongson.h>
+
+static uint nowait;
+
+static void (*saved_cpu_wait) (void);
+
+static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
+ unsigned long val, void *data);
+
+static struct notifier_block loongson2_cpufreq_notifier_block = {
+ .notifier_call = loongson2_cpu_freq_notifier
+};
+
+static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
+ unsigned long val, void *data)
+{
+ if (val == CPUFREQ_POSTCHANGE)
+ current_cpu_data.udelay_val = loops_per_jiffy;
+
+ return 0;
+}
+
+/*
+ * Here we notify other drivers of the proposed change and the final change.
+ */
+static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ unsigned int freq;
+
+ freq =
+ ((cpu_clock_freq / 1000) *
+ loongson2_clockmod_table[index].driver_data) / 8;
+
+ /* setting the cpu frequency */
+ clk_set_rate(policy->clk, freq * 1000);
+
+ return 0;
+}
+
+static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+ struct clk *cpuclk;
+ int i;
+ unsigned long rate;
+ int ret;
+
+ cpuclk = clk_get(NULL, "cpu_clk");
+ if (IS_ERR(cpuclk)) {
+ pr_err("couldn't get CPU clk\n");
+ return PTR_ERR(cpuclk);
+ }
+
+ rate = cpu_clock_freq / 1000;
+ if (!rate) {
+ clk_put(cpuclk);
+ return -EINVAL;
+ }
+
+ /* clock table init */
+ for (i = 2;
+ (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
+ i++)
+ loongson2_clockmod_table[i].frequency = (rate * i) / 8;
+
+ ret = clk_set_rate(cpuclk, rate * 1000);
+ if (ret) {
+ clk_put(cpuclk);
+ return ret;
+ }
+
+ policy->clk = cpuclk;
+ return cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);
+}
+
+static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
+{
+ clk_put(policy->clk);
+ return 0;
+}
+
+static struct cpufreq_driver loongson2_cpufreq_driver = {
+ .name = "loongson2",
+ .init = loongson2_cpufreq_cpu_init,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = loongson2_cpufreq_target,
+ .get = cpufreq_generic_get,
+ .exit = loongson2_cpufreq_exit,
+ .attr = cpufreq_generic_attr,
+};
+
+static const struct platform_device_id platform_device_ids[] = {
+ {
+ .name = "loongson2_cpufreq",
+ },
+ {}
+};
+
+MODULE_DEVICE_TABLE(platform, platform_device_ids);
+
+static struct platform_driver platform_driver = {
+ .driver = {
+ .name = "loongson2_cpufreq",
+ },
+ .id_table = platform_device_ids,
+};
+
+/*
+ * This is the simple version of Loongson-2 wait, Maybe we need do this in
+ * interrupt disabled context.
+ */
+
+static DEFINE_SPINLOCK(loongson2_wait_lock);
+
+static void loongson2_cpu_wait(void)
+{
+ unsigned long flags;
+ u32 cpu_freq;
+
+ spin_lock_irqsave(&loongson2_wait_lock, flags);
+ cpu_freq = LOONGSON_CHIPCFG(0);
+ LOONGSON_CHIPCFG(0) &= ~0x7; /* Put CPU into wait mode */
+ LOONGSON_CHIPCFG(0) = cpu_freq; /* Restore CPU state */
+ spin_unlock_irqrestore(&loongson2_wait_lock, flags);
+ local_irq_enable();
+}
+
+static int __init cpufreq_init(void)
+{
+ int ret;
+
+ /* Register platform stuff */
+ ret = platform_driver_register(&platform_driver);
+ if (ret)
+ return ret;
+
+ pr_info("Loongson-2F CPU frequency driver\n");
+
+ cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+
+ ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
+
+ if (!ret && !nowait) {
+ saved_cpu_wait = cpu_wait;
+ cpu_wait = loongson2_cpu_wait;
+ }
+
+ return ret;
+}
+
+static void __exit cpufreq_exit(void)
+{
+ if (!nowait && saved_cpu_wait)
+ cpu_wait = saved_cpu_wait;
+ cpufreq_unregister_driver(&loongson2_cpufreq_driver);
+ cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+
+ platform_driver_unregister(&platform_driver);
+}
+
+module_init(cpufreq_init);
+module_exit(cpufreq_exit);
+
+module_param(nowait, uint, 0644);
+MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
+
+MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
+MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
+MODULE_LICENSE("GPL");