initial Olimex linux tree from Daniel, originally Feb 3, 2016

1 files changed, 344 insertions, 0 deletions

diff --git a/linux/drivers/cpufreq/cpufreq-voltdm.c b/linux/drivers/cpufreq/cpufreq-voltdm.c
new file mode 100644
index 00000000..afe80ad5
--- /dev/null
+++ b/linux/drivers/cpufreq/cpufreq-voltdm.c
@@ -0,0 +1,344 @@
+/*
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ *
+ * Copyright (C) 2014 Linaro.
+ * Viresh Kumar <viresh.kumar@linaro.org>
+ *
+ * The OPP code in function set_target() is reused from
+ * drivers/cpufreq/omap-cpufreq.c
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/cpu.h>
+#include <linux/cpu_cooling.h>
+#include <linux/cpufreq.h>
+#include <linux/cpufreq-dt.h>
+#include <linux/cpumask.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm_opp.h>
+#include <linux/pm_voltage_domain.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+
+struct private_data {
+	struct device *cpu_dev;
+	struct thermal_cooling_device *cdev;
+	struct notifier_block *clk_nb;
+};
+
+static int set_target(struct cpufreq_policy *policy, unsigned int index)
+{
+	struct cpufreq_frequency_table *freq_table = policy->freq_table;
+	struct clk *cpu_clk = policy->clk;
+	struct private_data *priv = policy->driver_data;
+	struct device *cpu_dev = priv->cpu_dev;
+	unsigned int old_freq, new_freq;
+	long freq_Hz, freq_exact;
+	int ret;
+
+	freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
+	if (freq_Hz <= 0)
+		freq_Hz = freq_table[index].frequency * 1000;
+
+	freq_exact = freq_Hz;
+	new_freq = freq_Hz / 1000;
+	old_freq = clk_get_rate(cpu_clk) / 1000;
+
+	pr_debug("%u MHz --> %u MHz\n", old_freq / 1000, new_freq / 1000);
+
+	ret = clk_set_rate(cpu_clk, freq_exact);
+	if (ret) {
+		dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
+		return ret;
+	}
+
+	return ret;
+}
+
+static int allocate_resources(int cpu, struct device **cdev,
+			      struct clk **cclk)
+{
+	struct device *cpu_dev;
+	struct clk *cpu_clk;
+	int ret = 0;
+
+	cpu_dev = get_cpu_device(cpu);
+	if (!cpu_dev) {
+		pr_err("failed to get cpu%d device\n", cpu);
+		return -ENODEV;
+	}
+
+	cpu_clk = clk_get(cpu_dev, NULL);
+	if (IS_ERR(cpu_clk)) {
+		ret = PTR_ERR(cpu_clk);
+
+		/*
+		 * If cpu's clk node is present, but clock is not yet
+		 * registered, we should try defering probe.
+		 */
+		if (ret == -EPROBE_DEFER)
+			dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
+		else
+			dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu,
+				ret);
+	} else {
+		*cdev = cpu_dev;
+		*cclk = cpu_clk;
+	}
+
+	return ret;
+}
+
+static int cpufreq_init(struct cpufreq_policy *policy)
+{
+	struct cpufreq_dt_platform_data *pd;
+	struct cpufreq_frequency_table *freq_table;
+	struct device_node *np;
+	struct private_data *priv;
+	struct device *cpu_dev;
+	struct clk *cpu_clk;
+	unsigned int transition_latency, voltage_latency;
+	int ret;
+
+	ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_clk);
+	if (ret) {
+		pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
+		return ret;
+	}
+
+	np = of_node_get(cpu_dev->of_node);
+	if (!np) {
+		dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
+		ret = -ENOENT;
+		goto out_put_clk;
+	}
+
+	/* OPPs might be populated at runtime, don't check for error here */
+	of_init_opp_table(cpu_dev);
+
+	/*
+	 * But we need OPP table to function so if it is not there let's
+	 * give platform code chance to provide it for us.
+	 */
+	ret = dev_pm_opp_get_opp_count(cpu_dev);
+	if (ret <= 0) {
+		pr_debug("OPP table is not ready, deferring probe\n");
+		ret = -EPROBE_DEFER;
+		goto out_free_opp;
+	}
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		ret = -ENOMEM;
+		goto out_free_opp;
+	}
+
+	if (of_property_read_u32(np, "clock-latency", &transition_latency))
+		transition_latency = CPUFREQ_ETERNAL;
+
+	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
+	if (ret) {
+		pr_err("failed to init cpufreq table: %d\n", ret);
+		goto out_free_priv;
+	}
+
+	priv->cpu_dev = cpu_dev;
+	policy->driver_data = priv;
+
+	policy->clk = cpu_clk;
+	ret = cpufreq_table_validate_and_show(policy, freq_table);
+	if (ret) {
+		dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
+			ret);
+		goto out_free_cpufreq_table;
+	}
+
+	priv->clk_nb = of_pm_voltdm_notifier_register(cpu_dev, np,
+						      cpu_clk, "cpu0",
+						      &voltage_latency);
+
+	if (IS_ERR(priv->clk_nb)) {
+		ret = PTR_ERR(priv->clk_nb);
+		/* defer probe if regulator is not yet registered */
+		if (ret == -EPROBE_DEFER) {
+			dev_err(cpu_dev,
+				"cpu0 clock notifier not ready, retry\n");
+		} else {
+			dev_err(cpu_dev,
+				"Failed to register cpu0 clock notifier: %d\n",
+				ret);
+		}
+
+		goto out_free_cpufreq_table;
+	}
+
+	if (voltage_latency > 0)
+		transition_latency += voltage_latency;
+
+	policy->cpuinfo.transition_latency = transition_latency;
+	policy->suspend_freq = freq_table[0].frequency;
+
+	pd = cpufreq_get_driver_data();
+	if (!pd || !pd->independent_clocks)
+		cpumask_setall(policy->cpus);
+
+	of_node_put(np);
+
+	return 0;
+
+out_free_cpufreq_table:
+	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
+out_free_priv:
+	kfree(priv);
+out_free_opp:
+	of_free_opp_table(cpu_dev);
+	of_node_put(np);
+out_put_clk:
+	clk_put(cpu_clk);
+
+	return ret;
+}
+
+static int cpufreq_exit(struct cpufreq_policy *policy)
+{
+	struct private_data *priv = policy->driver_data;
+
+	cpufreq_cooling_unregister(priv->cdev);
+	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
+	of_pm_voltdm_notifier_unregister(priv->clk_nb);
+	of_free_opp_table(priv->cpu_dev);
+	clk_put(policy->clk);
+	kfree(priv);
+
+	return 0;
+}
+
+static void cpufreq_ready(struct cpufreq_policy *policy)
+{
+	struct private_data *priv = policy->driver_data;
+	struct device_node *np = of_node_get(priv->cpu_dev->of_node);
+
+	if (WARN_ON(!np))
+		return;
+
+	/*
+	 * For now, just loading the cooling device;
+	 * thermal DT code takes care of matching them.
+	 */
+	if (of_find_property(np, "#cooling-cells", NULL)) {
+		priv->cdev = of_cpufreq_cooling_register(np,
+							 policy->related_cpus);
+		if (IS_ERR(priv->cdev)) {
+			dev_err(priv->cpu_dev,
+				"running cpufreq without cooling device: %ld\n",
+				PTR_ERR(priv->cdev));
+
+			priv->cdev = NULL;
+		}
+	}
+
+	of_node_put(np);
+}
+
+static struct cpufreq_driver voltdm_cpufreq_driver = {
+	.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+	.verify = cpufreq_generic_frequency_table_verify,
+	.target_index = set_target,
+	.get = cpufreq_generic_get,
+	.init = cpufreq_init,
+	.exit = cpufreq_exit,
+	.ready = cpufreq_ready,
+	.name = "cpufreq-voltdm",
+	.attr = cpufreq_generic_attr,
+#ifdef CONFIG_PM
+	.suspend = cpufreq_generic_suspend,
+#endif
+};
+
+static int voltdm_cpufreq_probe(struct platform_device *pdev)
+{
+	struct device *cpu_dev;
+	struct clk *cpu_clk;
+	int ret, tmp;
+	struct notifier_block *clk_nb;
+	struct device_node *np;
+
+	/*
+	 * All per-cluster (CPUs sharing clock/voltages) initialization is done
+	 * from ->init(). In probe(), we just need to make sure that clk is
+	 * available. Else defer probe and retry.
+	 *
+	 * FIXME: Is checking this only for CPU0 sufficient ?
+	 */
+	ret = allocate_resources(0, &cpu_dev, &cpu_clk);
+	if (ret)
+		return ret;
+
+	np = cpu_dev->of_node;
+
+	/* OPPs might be populated at runtime, This is just a dummy setup */
+	of_init_opp_table(cpu_dev);
+
+	clk_nb = of_pm_voltdm_notifier_register(cpu_dev, np,
+						cpu_clk, "cpu0", &tmp);
+	of_free_opp_table(cpu_dev);
+
+	if (IS_ERR(clk_nb)) {
+		ret = PTR_ERR(clk_nb);
+		/* defer probe if regulator is not yet registered */
+		if (ret == -EPROBE_DEFER) {
+			dev_err(cpu_dev,
+				"cpu0 clock notifier not ready, retry\n");
+		} else {
+			dev_err(cpu_dev,
+				"Failed to register cpu0 clock notifier: %d\n",
+				ret);
+		}
+
+		clk_put(cpu_clk);
+		return ret;
+	}
+
+	if (clk_nb)
+		of_pm_voltdm_notifier_unregister(clk_nb);
+
+	clk_put(cpu_clk);
+
+	voltdm_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
+
+	ret = cpufreq_register_driver(&voltdm_cpufreq_driver);
+	if (ret)
+		dev_err(cpu_dev, "failed register driver: %d\n", ret);
+
+	return ret;
+}
+
+static int voltdm_cpufreq_remove(struct platform_device *pdev)
+{
+	cpufreq_unregister_driver(&voltdm_cpufreq_driver);
+	return 0;
+}
+
+static struct platform_driver voltdm_cpufreq_platdrv = {
+	.driver = {
+		.name	= "cpufreq-voltdm",
+	},
+	.probe		= voltdm_cpufreq_probe,
+	.remove		= voltdm_cpufreq_remove,
+};
+module_platform_driver(voltdm_cpufreq_platdrv);
+
+MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
+MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
+MODULE_DESCRIPTION("Generic cpufreq driver with clk notifier support");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:cpufreq-voltdm");