--- /dev/null
+/*
+ * CPU frequency scaling for OMAP using OPP information
+ *
+ * Copyright (C) 2005 Nokia Corporation
+ * Written by Tony Lindgren <tony@atomide.com>
+ *
+ * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
+ *
+ * Copyright (C) 2007-2011 Texas Instruments, Inc.
+ * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cpufreq.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/pm_opp.h>
+#include <linux/cpu.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#include <asm/smp_plat.h>
+#include <asm/cpu.h>
+
+/* OPP tolerance in percentage */
+#define OPP_TOLERANCE 4
+
+static struct cpufreq_frequency_table *freq_table;
+static atomic_t freq_table_users = ATOMIC_INIT(0);
+static struct device *mpu_dev;
+static struct regulator *mpu_reg;
+
+static int omap_target(struct cpufreq_policy *policy, unsigned int index)
+{
+ int r, ret;
+ struct dev_pm_opp *opp;
+ unsigned long freq, volt = 0, volt_old = 0, tol = 0;
+ unsigned int old_freq, new_freq;
+
+ old_freq = policy->cur;
+ new_freq = freq_table[index].frequency;
+
+ freq = new_freq * 1000;
+ ret = clk_round_rate(policy->clk, freq);
+ if (IS_ERR_VALUE(ret)) {
+ dev_warn(mpu_dev,
+ "CPUfreq: Cannot find matching frequency for %lu\n",
+ freq);
+ return ret;
+ }
+ freq = ret;
+
+ if (mpu_reg) {
+ rcu_read_lock();
+ opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
+ if (IS_ERR(opp)) {
+ rcu_read_unlock();
+ dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
+ __func__, new_freq);
+ return -EINVAL;
+ }
+ volt = dev_pm_opp_get_voltage(opp);
+ rcu_read_unlock();
+ tol = volt * OPP_TOLERANCE / 100;
+ volt_old = regulator_get_voltage(mpu_reg);
+ }
+
+ dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
+ old_freq / 1000, volt_old ? volt_old / 1000 : -1,
+ new_freq / 1000, volt ? volt / 1000 : -1);
+
+ /* scaling up? scale voltage before frequency */
+ if (mpu_reg && (new_freq > old_freq)) {
+ r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
+ if (r < 0) {
+ dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
+ __func__);
+ return r;
+ }
+ }
+
+ ret = clk_set_rate(policy->clk, new_freq * 1000);
+
+ /* scaling down? scale voltage after frequency */
+ if (mpu_reg && (new_freq < old_freq)) {
+ r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
+ if (r < 0) {
+ dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
+ __func__);
+ clk_set_rate(policy->clk, old_freq * 1000);
+ return r;
+ }
+ }
+
+ return ret;
+}
+
+static inline void freq_table_free(void)
+{
+ if (atomic_dec_and_test(&freq_table_users))
+ dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);
+}
+
+static int omap_cpu_init(struct cpufreq_policy *policy)
+{
+ int result;
+
+ policy->clk = clk_get(NULL, "cpufreq_ck");
+ if (IS_ERR(policy->clk))
+ return PTR_ERR(policy->clk);
+
+ if (!freq_table) {
+ result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);
+ if (result) {
+ dev_err(mpu_dev,
+ "%s: cpu%d: failed creating freq table[%d]\n",
+ __func__, policy->cpu, result);
+ goto fail;
+ }
+ }
+
+ atomic_inc_return(&freq_table_users);
+
+ /* FIXME: what's the actual transition time? */
+ result = cpufreq_generic_init(policy, freq_table, 300 * 1000);
+ if (!result)
+ return 0;
+
+ freq_table_free();
+fail:
+ clk_put(policy->clk);
+ return result;
+}
+
+static int omap_cpu_exit(struct cpufreq_policy *policy)
+{
+ freq_table_free();
+ clk_put(policy->clk);
+ return 0;
+}
+
+static struct cpufreq_driver omap_driver = {
+ .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = omap_target,
+ .get = cpufreq_generic_get,
+ .init = omap_cpu_init,
+ .exit = omap_cpu_exit,
+ .name = "omap",
+ .attr = cpufreq_generic_attr,
+};
+
+static int omap_cpufreq_probe(struct platform_device *pdev)
+{
+ mpu_dev = get_cpu_device(0);
+ if (!mpu_dev) {
+ pr_warning("%s: unable to get the mpu device\n", __func__);
+ return -EINVAL;
+ }
+
+ mpu_reg = regulator_get(mpu_dev, "vcc");
+ if (IS_ERR(mpu_reg)) {
+ pr_warning("%s: unable to get MPU regulator\n", __func__);
+ mpu_reg = NULL;
+ } else {
+ /*
+ * Ensure physical regulator is present.
+ * (e.g. could be dummy regulator.)
+ */
+ if (regulator_get_voltage(mpu_reg) < 0) {
+ pr_warn("%s: physical regulator not present for MPU\n",
+ __func__);
+ regulator_put(mpu_reg);
+ mpu_reg = NULL;
+ }
+ }
+
+ return cpufreq_register_driver(&omap_driver);
+}
+
+static int omap_cpufreq_remove(struct platform_device *pdev)
+{
+ return cpufreq_unregister_driver(&omap_driver);
+}
+
+static struct platform_driver omap_cpufreq_platdrv = {
+ .driver = {
+ .name = "omap-cpufreq",
+ },
+ .probe = omap_cpufreq_probe,
+ .remove = omap_cpufreq_remove,
+};
+module_platform_driver(omap_cpufreq_platdrv);
+
+MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff