1 files changed, 353 insertions, 0 deletions
diff --git a/drivers/cpufreq/ia64-acpi-cpufreq.c b/drivers/cpufreq/ia64-acpi-cpufreq.c
new file mode 100644
index 0000000000..c6bdc45551
--- /dev/null
+++ b/drivers/cpufreq/ia64-acpi-cpufreq.c
@@ -0,0 +1,353 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file provides the ACPI based P-state support. This
+ * module works with generic cpufreq infrastructure. Most of
+ * the code is based on i386 version
+ * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)
+ *
+ * Copyright (C) 2005 Intel Corp
+ *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/proc_fs.h>
+#include <asm/io.h>
+#include <linux/uaccess.h>
+#include <asm/pal.h>
+
+#include <linux/acpi.h>
+#include <acpi/processor.h>
+
+MODULE_AUTHOR("Venkatesh Pallipadi");
+MODULE_DESCRIPTION("ACPI Processor P-States Driver");
+MODULE_LICENSE("GPL");
+
+struct cpufreq_acpi_io {
+	struct acpi_processor_performance	acpi_data;
+	unsigned int				resume;
+};
+
+struct cpufreq_acpi_req {
+	unsigned int		cpu;
+	unsigned int		state;
+};
+
+static struct cpufreq_acpi_io	*acpi_io_data[NR_CPUS];
+
+static struct cpufreq_driver acpi_cpufreq_driver;
+
+
+static int
+processor_set_pstate (
+	u32	value)
+{
+	s64 retval;
+
+	pr_debug("processor_set_pstate\n");
+
+	retval = ia64_pal_set_pstate((u64)value);
+
+	if (retval) {
+		pr_debug("Failed to set freq to 0x%x, with error 0x%llx\n",
+		        value, retval);
+		return -ENODEV;
+	}
+	return (int)retval;
+}
+
+
+static int
+processor_get_pstate (
+	u32	*value)
+{
+	u64	pstate_index = 0;
+	s64 	retval;
+
+	pr_debug("processor_get_pstate\n");
+
+	retval = ia64_pal_get_pstate(&pstate_index,
+	                             PAL_GET_PSTATE_TYPE_INSTANT);
+	*value = (u32) pstate_index;
+
+	if (retval)
+		pr_debug("Failed to get current freq with "
+			"error 0x%llx, idx 0x%x\n", retval, *value);
+
+	return (int)retval;
+}
+
+
+/* To be used only after data->acpi_data is initialized */
+static unsigned
+extract_clock (
+	struct cpufreq_acpi_io *data,
+	unsigned value)
+{
+	unsigned long i;
+
+	pr_debug("extract_clock\n");
+
+	for (i = 0; i < data->acpi_data.state_count; i++) {
+		if (value == data->acpi_data.states[i].status)
+			return data->acpi_data.states[i].core_frequency;
+	}
+	return data->acpi_data.states[i-1].core_frequency;
+}
+
+
+static long
+processor_get_freq (
+	void *arg)
+{
+	struct cpufreq_acpi_req *req = arg;
+	unsigned int		cpu = req->cpu;
+	struct cpufreq_acpi_io	*data = acpi_io_data[cpu];
+	u32			value;
+	int			ret;
+
+	pr_debug("processor_get_freq\n");
+	if (smp_processor_id() != cpu)
+		return -EAGAIN;
+
+	/* processor_get_pstate gets the instantaneous frequency */
+	ret = processor_get_pstate(&value);
+	if (ret) {
+		pr_warn("get performance failed with error %d\n", ret);
+		return ret;
+	}
+	return 1000 * extract_clock(data, value);
+}
+
+
+static long
+processor_set_freq (
+	void *arg)
+{
+	struct cpufreq_acpi_req *req = arg;
+	unsigned int		cpu = req->cpu;
+	struct cpufreq_acpi_io	*data = acpi_io_data[cpu];
+	int			ret, state = req->state;
+	u32			value;
+
+	pr_debug("processor_set_freq\n");
+	if (smp_processor_id() != cpu)
+		return -EAGAIN;
+
+	if (state == data->acpi_data.state) {
+		if (unlikely(data->resume)) {
+			pr_debug("Called after resume, resetting to P%d\n", state);
+			data->resume = 0;
+		} else {
+			pr_debug("Already at target state (P%d)\n", state);
+			return 0;
+		}
+	}
+
+	pr_debug("Transitioning from P%d to P%d\n",
+		data->acpi_data.state, state);
+
+	/*
+	 * First we write the target state's 'control' value to the
+	 * control_register.
+	 */
+	value = (u32) data->acpi_data.states[state].control;
+
+	pr_debug("Transitioning to state: 0x%08x\n", value);
+
+	ret = processor_set_pstate(value);
+	if (ret) {
+		pr_warn("Transition failed with error %d\n", ret);
+		return -ENODEV;
+	}
+
+	data->acpi_data.state = state;
+	return 0;
+}
+
+
+static unsigned int
+acpi_cpufreq_get (
+	unsigned int		cpu)
+{
+	struct cpufreq_acpi_req req;
+	long ret;
+
+	req.cpu = cpu;
+	ret = work_on_cpu(cpu, processor_get_freq, &req);
+
+	return ret > 0 ? (unsigned int) ret : 0;
+}
+
+
+static int
+acpi_cpufreq_target (
+	struct cpufreq_policy   *policy,
+	unsigned int index)
+{
+	struct cpufreq_acpi_req req;
+
+	req.cpu = policy->cpu;
+	req.state = index;
+
+	return work_on_cpu(req.cpu, processor_set_freq, &req);
+}
+
+static int
+acpi_cpufreq_cpu_init (
+	struct cpufreq_policy   *policy)
+{
+	unsigned int		i;
+	unsigned int		cpu = policy->cpu;
+	struct cpufreq_acpi_io	*data;
+	unsigned int		result = 0;
+	struct cpufreq_frequency_table *freq_table;
+
+	pr_debug("acpi_cpufreq_cpu_init\n");
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return (-ENOMEM);
+
+	acpi_io_data[cpu] = data;
+
+	result = acpi_processor_register_performance(&data->acpi_data, cpu);
+
+	if (result)
+		goto err_free;
+
+	/* capability check */
+	if (data->acpi_data.state_count <= 1) {
+		pr_debug("No P-States\n");
+		result = -ENODEV;
+		goto err_unreg;
+	}
+
+	if ((data->acpi_data.control_register.space_id !=
+					ACPI_ADR_SPACE_FIXED_HARDWARE) ||
+	    (data->acpi_data.status_register.space_id !=
+					ACPI_ADR_SPACE_FIXED_HARDWARE)) {
+		pr_debug("Unsupported address space [%d, %d]\n",
+			(u32) (data->acpi_data.control_register.space_id),
+			(u32) (data->acpi_data.status_register.space_id));
+		result = -ENODEV;
+		goto err_unreg;
+	}
+
+	/* alloc freq_table */
+	freq_table = kcalloc(data->acpi_data.state_count + 1,
+	                           sizeof(*freq_table),
+	                           GFP_KERNEL);
+	if (!freq_table) {
+		result = -ENOMEM;
+		goto err_unreg;
+	}
+
+	/* detect transition latency */
+	policy->cpuinfo.transition_latency = 0;
+	for (i=0; i<data->acpi_data.state_count; i++) {
+		if ((data->acpi_data.states[i].transition_latency * 1000) >
+		    policy->cpuinfo.transition_latency) {
+			policy->cpuinfo.transition_latency =
+			    data->acpi_data.states[i].transition_latency * 1000;
+		}
+	}
+
+	/* table init */
+	for (i = 0; i <= data->acpi_data.state_count; i++)
+	{
+		if (i < data->acpi_data.state_count) {
+			freq_table[i].frequency =
+			      data->acpi_data.states[i].core_frequency * 1000;
+		} else {
+			freq_table[i].frequency = CPUFREQ_TABLE_END;
+		}
+	}
+
+	policy->freq_table = freq_table;
+
+	/* notify BIOS that we exist */
+	acpi_processor_notify_smm(THIS_MODULE);
+
+	pr_info("CPU%u - ACPI performance management activated\n", cpu);
+
+	for (i = 0; i < data->acpi_data.state_count; i++)
+		pr_debug("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
+			(i == data->acpi_data.state?'*':' '), i,
+			(u32) data->acpi_data.states[i].core_frequency,
+			(u32) data->acpi_data.states[i].power,
+			(u32) data->acpi_data.states[i].transition_latency,
+			(u32) data->acpi_data.states[i].bus_master_latency,
+			(u32) data->acpi_data.states[i].status,
+			(u32) data->acpi_data.states[i].control);
+
+	/* the first call to ->target() should result in us actually
+	 * writing something to the appropriate registers. */
+	data->resume = 1;
+
+	return (result);
+
+ err_unreg:
+	acpi_processor_unregister_performance(cpu);
+ err_free:
+	kfree(data);
+	acpi_io_data[cpu] = NULL;
+
+	return (result);
+}
+
+
+static int
+acpi_cpufreq_cpu_exit (
+	struct cpufreq_policy   *policy)
+{
+	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
+
+	pr_debug("acpi_cpufreq_cpu_exit\n");
+
+	if (data) {
+		acpi_io_data[policy->cpu] = NULL;
+		acpi_processor_unregister_performance(policy->cpu);
+		kfree(policy->freq_table);
+		kfree(data);
+	}
+
+	return (0);
+}
+
+
+static struct cpufreq_driver acpi_cpufreq_driver = {
+	.verify 	= cpufreq_generic_frequency_table_verify,
+	.target_index	= acpi_cpufreq_target,
+	.get 		= acpi_cpufreq_get,
+	.init		= acpi_cpufreq_cpu_init,
+	.exit		= acpi_cpufreq_cpu_exit,
+	.name		= "acpi-cpufreq",
+	.attr		= cpufreq_generic_attr,
+};
+
+
+static int __init
+acpi_cpufreq_init (void)
+{
+	pr_debug("acpi_cpufreq_init\n");
+
+ 	return cpufreq_register_driver(&acpi_cpufreq_driver);
+}
+
+
+static void __exit
+acpi_cpufreq_exit (void)
+{
+	pr_debug("acpi_cpufreq_exit\n");
+
+	cpufreq_unregister_driver(&acpi_cpufreq_driver);
+}
+
+late_initcall(acpi_cpufreq_init);
+module_exit(acpi_cpufreq_exit);