1 files changed, 322 insertions, 0 deletions
diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c
new file mode 100644
index 000000000..e534fd49a
--- /dev/null
+++ b/drivers/acpi/processor_thermal.c
@@ -0,0 +1,322 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
+ *
+ *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
+ *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
+ *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
+ *  			- Added processor hotplug support
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/acpi.h>
+#include <acpi/processor.h>
+#include <linux/uaccess.h>
+
+#ifdef CONFIG_CPU_FREQ
+
+/* If a passive cooling situation is detected, primarily CPUfreq is used, as it
+ * offers (in most cases) voltage scaling in addition to frequency scaling, and
+ * thus a cubic (instead of linear) reduction of energy. Also, we allow for
+ * _any_ cpufreq driver and not only the acpi-cpufreq driver.
+ */
+
+#define CPUFREQ_THERMAL_MIN_STEP 0
+#define CPUFREQ_THERMAL_MAX_STEP 3
+
+static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
+
+#define reduction_pctg(cpu) \
+	per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
+
+/*
+ * Emulate "per package data" using per cpu data (which should really be
+ * provided elsewhere)
+ *
+ * Note we can lose a CPU on cpu hotunplug, in this case we forget the state
+ * temporarily. Fortunately that's not a big issue here (I hope)
+ */
+static int phys_package_first_cpu(int cpu)
+{
+	int i;
+	int id = topology_physical_package_id(cpu);
+
+	for_each_online_cpu(i)
+		if (topology_physical_package_id(i) == id)
+			return i;
+	return 0;
+}
+
+static int cpu_has_cpufreq(unsigned int cpu)
+{
+	struct cpufreq_policy *policy;
+
+	if (!acpi_processor_cpufreq_init)
+		return 0;
+
+	policy = cpufreq_cpu_get(cpu);
+	if (policy) {
+		cpufreq_cpu_put(policy);
+		return 1;
+	}
+	return 0;
+}
+
+static int cpufreq_get_max_state(unsigned int cpu)
+{
+	if (!cpu_has_cpufreq(cpu))
+		return 0;
+
+	return CPUFREQ_THERMAL_MAX_STEP;
+}
+
+static int cpufreq_get_cur_state(unsigned int cpu)
+{
+	if (!cpu_has_cpufreq(cpu))
+		return 0;
+
+	return reduction_pctg(cpu);
+}
+
+static int cpufreq_set_cur_state(unsigned int cpu, int state)
+{
+	struct cpufreq_policy *policy;
+	struct acpi_processor *pr;
+	unsigned long max_freq;
+	int i, ret;
+
+	if (!cpu_has_cpufreq(cpu))
+		return 0;
+
+	reduction_pctg(cpu) = state;
+
+	/*
+	 * Update all the CPUs in the same package because they all
+	 * contribute to the temperature and often share the same
+	 * frequency.
+	 */
+	for_each_online_cpu(i) {
+		if (topology_physical_package_id(i) !=
+		    topology_physical_package_id(cpu))
+			continue;
+
+		pr = per_cpu(processors, i);
+
+		if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
+			continue;
+
+		policy = cpufreq_cpu_get(i);
+		if (!policy)
+			return -EINVAL;
+
+		max_freq = (policy->cpuinfo.max_freq * (100 - reduction_pctg(i) * 20)) / 100;
+
+		cpufreq_cpu_put(policy);
+
+		ret = freq_qos_update_request(&pr->thermal_req, max_freq);
+		if (ret < 0) {
+			pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
+				pr->id, ret);
+		}
+	}
+	return 0;
+}
+
+void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
+{
+	unsigned int cpu;
+
+	for_each_cpu(cpu, policy->related_cpus) {
+		struct acpi_processor *pr = per_cpu(processors, cpu);
+		int ret;
+
+		if (!pr)
+			continue;
+
+		ret = freq_qos_add_request(&policy->constraints,
+					   &pr->thermal_req,
+					   FREQ_QOS_MAX, INT_MAX);
+		if (ret < 0)
+			pr_err("Failed to add freq constraint for CPU%d (%d)\n",
+			       cpu, ret);
+	}
+}
+
+void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
+{
+	unsigned int cpu;
+
+	for_each_cpu(cpu, policy->related_cpus) {
+		struct acpi_processor *pr = per_cpu(processors, cpu);
+
+		if (pr)
+			freq_qos_remove_request(&pr->thermal_req);
+	}
+}
+#else				/* ! CONFIG_CPU_FREQ */
+static int cpufreq_get_max_state(unsigned int cpu)
+{
+	return 0;
+}
+
+static int cpufreq_get_cur_state(unsigned int cpu)
+{
+	return 0;
+}
+
+static int cpufreq_set_cur_state(unsigned int cpu, int state)
+{
+	return 0;
+}
+
+#endif
+
+/* thermal cooling device callbacks */
+static int acpi_processor_max_state(struct acpi_processor *pr)
+{
+	int max_state = 0;
+
+	/*
+	 * There exists four states according to
+	 * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
+	 */
+	max_state += cpufreq_get_max_state(pr->id);
+	if (pr->flags.throttling)
+		max_state += (pr->throttling.state_count -1);
+
+	return max_state;
+}
+static int
+processor_get_max_state(struct thermal_cooling_device *cdev,
+			unsigned long *state)
+{
+	struct acpi_device *device = cdev->devdata;
+	struct acpi_processor *pr;
+
+	if (!device)
+		return -EINVAL;
+
+	pr = acpi_driver_data(device);
+	if (!pr)
+		return -EINVAL;
+
+	*state = acpi_processor_max_state(pr);
+	return 0;
+}
+
+static int
+processor_get_cur_state(struct thermal_cooling_device *cdev,
+			unsigned long *cur_state)
+{
+	struct acpi_device *device = cdev->devdata;
+	struct acpi_processor *pr;
+
+	if (!device)
+		return -EINVAL;
+
+	pr = acpi_driver_data(device);
+	if (!pr)
+		return -EINVAL;
+
+	*cur_state = cpufreq_get_cur_state(pr->id);
+	if (pr->flags.throttling)
+		*cur_state += pr->throttling.state;
+	return 0;
+}
+
+static int
+processor_set_cur_state(struct thermal_cooling_device *cdev,
+			unsigned long state)
+{
+	struct acpi_device *device = cdev->devdata;
+	struct acpi_processor *pr;
+	int result = 0;
+	int max_pstate;
+
+	if (!device)
+		return -EINVAL;
+
+	pr = acpi_driver_data(device);
+	if (!pr)
+		return -EINVAL;
+
+	max_pstate = cpufreq_get_max_state(pr->id);
+
+	if (state > acpi_processor_max_state(pr))
+		return -EINVAL;
+
+	if (state <= max_pstate) {
+		if (pr->flags.throttling && pr->throttling.state)
+			result = acpi_processor_set_throttling(pr, 0, false);
+		cpufreq_set_cur_state(pr->id, state);
+	} else {
+		cpufreq_set_cur_state(pr->id, max_pstate);
+		result = acpi_processor_set_throttling(pr,
+				state - max_pstate, false);
+	}
+	return result;
+}
+
+const struct thermal_cooling_device_ops processor_cooling_ops = {
+	.get_max_state = processor_get_max_state,
+	.get_cur_state = processor_get_cur_state,
+	.set_cur_state = processor_set_cur_state,
+};
+
+int acpi_processor_thermal_init(struct acpi_processor *pr,
+				struct acpi_device *device)
+{
+	int result = 0;
+
+	pr->cdev = thermal_cooling_device_register("Processor", device,
+						   &processor_cooling_ops);
+	if (IS_ERR(pr->cdev)) {
+		result = PTR_ERR(pr->cdev);
+		return result;
+	}
+
+	dev_dbg(&device->dev, "registered as cooling_device%d\n",
+		pr->cdev->id);
+
+	result = sysfs_create_link(&device->dev.kobj,
+				   &pr->cdev->device.kobj,
+				   "thermal_cooling");
+	if (result) {
+		dev_err(&device->dev,
+			"Failed to create sysfs link 'thermal_cooling'\n");
+		goto err_thermal_unregister;
+	}
+
+	result = sysfs_create_link(&pr->cdev->device.kobj,
+				   &device->dev.kobj,
+				   "device");
+	if (result) {
+		dev_err(&pr->cdev->device,
+			"Failed to create sysfs link 'device'\n");
+		goto err_remove_sysfs_thermal;
+	}
+
+	return 0;
+
+err_remove_sysfs_thermal:
+	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
+err_thermal_unregister:
+	thermal_cooling_device_unregister(pr->cdev);
+
+	return result;
+}
+
+void acpi_processor_thermal_exit(struct acpi_processor *pr,
+				 struct acpi_device *device)
+{
+	if (pr->cdev) {
+		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
+		sysfs_remove_link(&pr->cdev->device.kobj, "device");
+		thermal_cooling_device_unregister(pr->cdev);
+		pr->cdev = NULL;
+	}
+}