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Diffstat (limited to 'drivers/cpufreq/ia64-acpi-cpufreq.c')
-rw-r--r--drivers/cpufreq/ia64-acpi-cpufreq.c353
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);