cpufreq: mips: move cpufreq driver to drivers/cpufreq

This patch moves cpufreq driver of MIPS architecture to drivers/cpufreq.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 267 insertions, 0 deletions

diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index a2f1600c78f8..5030df5cd3eb 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -235,6 +235,24 @@ config IA64_ACPI_CPUFREQ
 
 endmenu
 
+menu "MIPS CPUFreq processor drivers"
+depends on MIPS
+
+config LOONGSON2_CPUFREQ
+        tristate "Loongson2 CPUFreq Driver"
+        select CPU_FREQ_TABLE
+        help
+          This option adds a CPUFreq driver for loongson processors which
+          support software configurable cpu frequency.
+
+          Loongson2F and it's successors support this feature.
+
+          For details, take a look at <file:Documentation/cpu-freq/>.
+
+          If in doubt, say N.
+
+endmenu
+
 menu "PowerPC CPU frequency scaling drivers"
 depends on PPC32 || PPC64
 source "drivers/cpufreq/Kconfig.powerpc"
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index ab681337e6d4..9659cbbad25e 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -82,3 +82,4 @@ obj-$(CONFIG_BLACKFIN)			+= blackfin-cpufreq.o
 obj-$(CONFIG_CRIS_MACH_ARTPEC3)         += cris-artpec3-cpufreq.o
 obj-$(CONFIG_ETRAXFS)                   += cris-etraxfs-cpufreq.o
 obj-$(CONFIG_IA64_ACPI_CPUFREQ)         += ia64-acpi-cpufreq.o
+obj-$(CONFIG_LOONGSON2_CPUFREQ)         += loongson2_cpufreq.o
diff --git a/drivers/cpufreq/loongson2_cpufreq.c b/drivers/cpufreq/loongson2_cpufreq.c
new file mode 100644
index 000000000000..84889573b566
--- /dev/null
+++ b/drivers/cpufreq/loongson2_cpufreq.c
@@ -0,0 +1,248 @@
+/*
+ * Cpufreq driver for the loongson-2 processors
+ *
+ * The 2E revision of loongson processor not support this feature.
+ *
+ * Copyright (C) 2006 - 2008 Lemote Inc. & Insititute 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.
+ */
+#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/mach-loongson/loongson.h>
+
+static uint nowait;
+
+static struct clk *cpuclk;
+
+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;
+}
+
+static unsigned int loongson2_cpufreq_get(unsigned int cpu)
+{
+        return clk_get_rate(cpuclk);
+}
+
+/*
+ * Here we notify other drivers of the proposed change and the final change.
+ */
+static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
+                                     unsigned int target_freq,
+                                     unsigned int relation)
+{
+        unsigned int cpu = policy->cpu;
+        unsigned int newstate = 0;
+        cpumask_t cpus_allowed;
+        struct cpufreq_freqs freqs;
+        unsigned int freq;
+
+        cpus_allowed = current->cpus_allowed;
+        set_cpus_allowed_ptr(current, cpumask_of(cpu));
+
+        if (cpufreq_frequency_table_target
+            (policy, &loongson2_clockmod_table[0], target_freq, relation,
+             &newstate))
+                return -EINVAL;
+
+        freq =
+            ((cpu_clock_freq / 1000) *
+             loongson2_clockmod_table[newstate].index) / 8;
+        if (freq < policy->min || freq > policy->max)
+                return -EINVAL;
+
+        pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
+
+        freqs.old = loongson2_cpufreq_get(cpu);
+        freqs.new = freq;
+        freqs.flags = 0;
+
+        if (freqs.new == freqs.old)
+                return 0;
+
+        /* notifiers */
+        cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
+
+        set_cpus_allowed_ptr(current, &cpus_allowed);
+
+        /* setting the cpu frequency */
+        clk_set_rate(cpuclk, freq);
+
+        /* notifiers */
+        cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
+
+        pr_debug("cpufreq: set frequency %u kHz\n", freq);
+
+        return 0;
+}
+
+static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+        int i;
+        unsigned long rate;
+        int ret;
+
+        cpuclk = clk_get(NULL, "cpu_clk");
+        if (IS_ERR(cpuclk)) {
+                printk(KERN_ERR "cpufreq: couldn't get CPU clk\n");
+                return PTR_ERR(cpuclk);
+        }
+
+        rate = cpu_clock_freq / 1000;
+        if (!rate) {
+                clk_put(cpuclk);
+                return -EINVAL;
+        }
+        ret = clk_set_rate(cpuclk, rate);
+        if (ret) {
+                clk_put(cpuclk);
+                return ret;
+        }
+
+        /* clock table init */
+        for (i = 2;
+             (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
+             i++)
+                loongson2_clockmod_table[i].frequency = (rate * i) / 8;
+
+        policy->cur = loongson2_cpufreq_get(policy->cpu);
+
+        cpufreq_frequency_table_get_attr(&loongson2_clockmod_table[0],
+                                         policy->cpu);
+
+        return cpufreq_frequency_table_cpuinfo(policy,
+                                            &loongson2_clockmod_table[0]);
+}
+
+static int loongson2_cpufreq_verify(struct cpufreq_policy *policy)
+{
+        return cpufreq_frequency_table_verify(policy,
+                                              &loongson2_clockmod_table[0]);
+}
+
+static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
+{
+        clk_put(cpuclk);
+        return 0;
+}
+
+static struct freq_attr *loongson2_table_attr[] = {
+        &cpufreq_freq_attr_scaling_available_freqs,
+        NULL,
+};
+
+static struct cpufreq_driver loongson2_cpufreq_driver = {
+        .owner = THIS_MODULE,
+        .name = "loongson2",
+        .init = loongson2_cpufreq_cpu_init,
+        .verify = loongson2_cpufreq_verify,
+        .target = loongson2_cpufreq_target,
+        .get = loongson2_cpufreq_get,
+        .exit = loongson2_cpufreq_exit,
+        .attr = loongson2_table_attr,
+};
+
+static 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",
+                .owner = THIS_MODULE,
+        },
+        .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_CHIPCFG0;
+        LOONGSON_CHIPCFG0 &= ~0x7;      /* Put CPU into wait mode */
+        LOONGSON_CHIPCFG0 = cpu_freq;   /* Restore CPU state */
+        spin_unlock_irqrestore(&loongson2_wait_lock, flags);
+}
+
+static int __init cpufreq_init(void)
+{
+        int ret;
+
+        /* Register platform stuff */
+        ret = platform_driver_register(&platform_driver);
+        if (ret)
+                return ret;
+
+        pr_info("cpufreq: 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");