cpufreq: tegra: Move driver to drivers/cpufreq

This patch moves cpufreq driver of ARM based tegra platform to drivers/cpufreq.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 292 insertions, 0 deletions

diff --git a/drivers/cpufreq/tegra-cpufreq.c b/drivers/cpufreq/tegra-cpufreq.c
new file mode 100644
index 000000000000..c74c0e130ef4
--- /dev/null
+++ b/drivers/cpufreq/tegra-cpufreq.c
@@ -0,0 +1,292 @@
+/*
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ *	Colin Cross <ccross@google.com>
+ *	Based on arch/arm/plat-omap/cpu-omap.c, (C) 2005 Nokia Corporation
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.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/suspend.h>
+
+/* Frequency table index must be sequential starting at 0 */
+static struct cpufreq_frequency_table freq_table[] = {
+	{ 0, 216000 },
+	{ 1, 312000 },
+	{ 2, 456000 },
+	{ 3, 608000 },
+	{ 4, 760000 },
+	{ 5, 816000 },
+	{ 6, 912000 },
+	{ 7, 1000000 },
+	{ 8, CPUFREQ_TABLE_END },
+};
+
+#define NUM_CPUS	2
+
+static struct clk *cpu_clk;
+static struct clk *pll_x_clk;
+static struct clk *pll_p_clk;
+static struct clk *emc_clk;
+
+static unsigned long target_cpu_speed[NUM_CPUS];
+static DEFINE_MUTEX(tegra_cpu_lock);
+static bool is_suspended;
+
+static int tegra_verify_speed(struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy, freq_table);
+}
+
+static unsigned int tegra_getspeed(unsigned int cpu)
+{
+	unsigned long rate;
+
+	if (cpu >= NUM_CPUS)
+		return 0;
+
+	rate = clk_get_rate(cpu_clk) / 1000;
+	return rate;
+}
+
+static int tegra_cpu_clk_set_rate(unsigned long rate)
+{
+	int ret;
+
+	/*
+	 * Take an extra reference to the main pll so it doesn't turn
+	 * off when we move the cpu off of it
+	 */
+	clk_prepare_enable(pll_x_clk);
+
+	ret = clk_set_parent(cpu_clk, pll_p_clk);
+	if (ret) {
+		pr_err("Failed to switch cpu to clock pll_p\n");
+		goto out;
+	}
+
+	if (rate == clk_get_rate(pll_p_clk))
+		goto out;
+
+	ret = clk_set_rate(pll_x_clk, rate);
+	if (ret) {
+		pr_err("Failed to change pll_x to %lu\n", rate);
+		goto out;
+	}
+
+	ret = clk_set_parent(cpu_clk, pll_x_clk);
+	if (ret) {
+		pr_err("Failed to switch cpu to clock pll_x\n");
+		goto out;
+	}
+
+out:
+	clk_disable_unprepare(pll_x_clk);
+	return ret;
+}
+
+static int tegra_update_cpu_speed(struct cpufreq_policy *policy,
+		unsigned long rate)
+{
+	int ret = 0;
+	struct cpufreq_freqs freqs;
+
+	freqs.old = tegra_getspeed(0);
+	freqs.new = rate;
+
+	if (freqs.old == freqs.new)
+		return ret;
+
+	/*
+	 * Vote on memory bus frequency based on cpu frequency
+	 * This sets the minimum frequency, display or avp may request higher
+	 */
+	if (rate >= 816000)
+		clk_set_rate(emc_clk, 600000000); /* cpu 816 MHz, emc max */
+	else if (rate >= 456000)
+		clk_set_rate(emc_clk, 300000000); /* cpu 456 MHz, emc 150Mhz */
+	else
+		clk_set_rate(emc_clk, 100000000);  /* emc 50Mhz */
+
+	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
+
+#ifdef CONFIG_CPU_FREQ_DEBUG
+	printk(KERN_DEBUG "cpufreq-tegra: transition: %u --> %u\n",
+	       freqs.old, freqs.new);
+#endif
+
+	ret = tegra_cpu_clk_set_rate(freqs.new * 1000);
+	if (ret) {
+		pr_err("cpu-tegra: Failed to set cpu frequency to %d kHz\n",
+			freqs.new);
+		return ret;
+	}
+
+	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
+
+	return 0;
+}
+
+static unsigned long tegra_cpu_highest_speed(void)
+{
+	unsigned long rate = 0;
+	int i;
+
+	for_each_online_cpu(i)
+		rate = max(rate, target_cpu_speed[i]);
+	return rate;
+}
+
+static int tegra_target(struct cpufreq_policy *policy,
+		       unsigned int target_freq,
+		       unsigned int relation)
+{
+	unsigned int idx;
+	unsigned int freq;
+	int ret = 0;
+
+	mutex_lock(&tegra_cpu_lock);
+
+	if (is_suspended) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	cpufreq_frequency_table_target(policy, freq_table, target_freq,
+		relation, &idx);
+
+	freq = freq_table[idx].frequency;
+
+	target_cpu_speed[policy->cpu] = freq;
+
+	ret = tegra_update_cpu_speed(policy, tegra_cpu_highest_speed());
+
+out:
+	mutex_unlock(&tegra_cpu_lock);
+	return ret;
+}
+
+static int tegra_pm_notify(struct notifier_block *nb, unsigned long event,
+	void *dummy)
+{
+	mutex_lock(&tegra_cpu_lock);
+	if (event == PM_SUSPEND_PREPARE) {
+		struct cpufreq_policy *policy = cpufreq_cpu_get(0);
+		is_suspended = true;
+		pr_info("Tegra cpufreq suspend: setting frequency to %d kHz\n",
+			freq_table[0].frequency);
+		tegra_update_cpu_speed(policy, freq_table[0].frequency);
+		cpufreq_cpu_put(policy);
+	} else if (event == PM_POST_SUSPEND) {
+		is_suspended = false;
+	}
+	mutex_unlock(&tegra_cpu_lock);
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block tegra_cpu_pm_notifier = {
+	.notifier_call = tegra_pm_notify,
+};
+
+static int tegra_cpu_init(struct cpufreq_policy *policy)
+{
+	if (policy->cpu >= NUM_CPUS)
+		return -EINVAL;
+
+	clk_prepare_enable(emc_clk);
+	clk_prepare_enable(cpu_clk);
+
+	cpufreq_frequency_table_cpuinfo(policy, freq_table);
+	cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
+	policy->cur = tegra_getspeed(policy->cpu);
+	target_cpu_speed[policy->cpu] = policy->cur;
+
+	/* FIXME: what's the actual transition time? */
+	policy->cpuinfo.transition_latency = 300 * 1000;
+
+	cpumask_copy(policy->cpus, cpu_possible_mask);
+
+	if (policy->cpu == 0)
+		register_pm_notifier(&tegra_cpu_pm_notifier);
+
+	return 0;
+}
+
+static int tegra_cpu_exit(struct cpufreq_policy *policy)
+{
+	cpufreq_frequency_table_cpuinfo(policy, freq_table);
+	clk_disable_unprepare(emc_clk);
+	return 0;
+}
+
+static struct freq_attr *tegra_cpufreq_attr[] = {
+	&cpufreq_freq_attr_scaling_available_freqs,
+	NULL,
+};
+
+static struct cpufreq_driver tegra_cpufreq_driver = {
+	.verify		= tegra_verify_speed,
+	.target		= tegra_target,
+	.get		= tegra_getspeed,
+	.init		= tegra_cpu_init,
+	.exit		= tegra_cpu_exit,
+	.name		= "tegra",
+	.attr		= tegra_cpufreq_attr,
+};
+
+static int __init tegra_cpufreq_init(void)
+{
+	cpu_clk = clk_get_sys(NULL, "cpu");
+	if (IS_ERR(cpu_clk))
+		return PTR_ERR(cpu_clk);
+
+	pll_x_clk = clk_get_sys(NULL, "pll_x");
+	if (IS_ERR(pll_x_clk))
+		return PTR_ERR(pll_x_clk);
+
+	pll_p_clk = clk_get_sys(NULL, "pll_p_cclk");
+	if (IS_ERR(pll_p_clk))
+		return PTR_ERR(pll_p_clk);
+
+	emc_clk = clk_get_sys("cpu", "emc");
+	if (IS_ERR(emc_clk)) {
+		clk_put(cpu_clk);
+		return PTR_ERR(emc_clk);
+	}
+
+	return cpufreq_register_driver(&tegra_cpufreq_driver);
+}
+
+static void __exit tegra_cpufreq_exit(void)
+{
+        cpufreq_unregister_driver(&tegra_cpufreq_driver);
+	clk_put(emc_clk);
+	clk_put(cpu_clk);
+}
+
+
+MODULE_AUTHOR("Colin Cross <ccross@android.com>");
+MODULE_DESCRIPTION("cpufreq driver for Nvidia Tegra2");
+MODULE_LICENSE("GPL");
+module_init(tegra_cpufreq_init);
+module_exit(tegra_cpufreq_exit);