e7ddf4b7b3
This adds the SFI based cpu freq driver for some of the Intel's Silvermont based Atom architectures like Z34xx and Z35xx. Signed-off-by: Rudramuni, Vishwesh M <vishwesh.m.rudramuni@intel.com> Signed-off-by: Srinidhi Kasagar <srinidhi.kasagar@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Len Brown <len.brown@intel.com>
136 lines
3.6 KiB
C
136 lines
3.6 KiB
C
/*
|
|
* SFI Performance States Driver
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License.
|
|
*
|
|
* 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.
|
|
*
|
|
* Author: Vishwesh M Rudramuni <vishwesh.m.rudramuni@intel.com>
|
|
* Author: Srinidhi Kasagar <srinidhi.kasagar@intel.com>
|
|
*/
|
|
|
|
#include <linux/cpufreq.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/sfi.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/smp.h>
|
|
|
|
#include <asm/msr.h>
|
|
|
|
struct cpufreq_frequency_table *freq_table;
|
|
static struct sfi_freq_table_entry *sfi_cpufreq_array;
|
|
static int num_freq_table_entries;
|
|
|
|
static int sfi_parse_freq(struct sfi_table_header *table)
|
|
{
|
|
struct sfi_table_simple *sb;
|
|
struct sfi_freq_table_entry *pentry;
|
|
int totallen;
|
|
|
|
sb = (struct sfi_table_simple *)table;
|
|
num_freq_table_entries = SFI_GET_NUM_ENTRIES(sb,
|
|
struct sfi_freq_table_entry);
|
|
if (num_freq_table_entries <= 1) {
|
|
pr_err("No p-states discovered\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
pentry = (struct sfi_freq_table_entry *)sb->pentry;
|
|
totallen = num_freq_table_entries * sizeof(*pentry);
|
|
|
|
sfi_cpufreq_array = kzalloc(totallen, GFP_KERNEL);
|
|
if (!sfi_cpufreq_array)
|
|
return -ENOMEM;
|
|
|
|
memcpy(sfi_cpufreq_array, pentry, totallen);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sfi_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
|
|
{
|
|
unsigned int next_perf_state = 0; /* Index into perf table */
|
|
u32 lo, hi;
|
|
|
|
next_perf_state = policy->freq_table[index].driver_data;
|
|
|
|
rdmsr_on_cpu(policy->cpu, MSR_IA32_PERF_CTL, &lo, &hi);
|
|
lo = (lo & ~INTEL_PERF_CTL_MASK) |
|
|
((u32) sfi_cpufreq_array[next_perf_state].ctrl_val &
|
|
INTEL_PERF_CTL_MASK);
|
|
wrmsr_on_cpu(policy->cpu, MSR_IA32_PERF_CTL, lo, hi);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sfi_cpufreq_cpu_init(struct cpufreq_policy *policy)
|
|
{
|
|
policy->shared_type = CPUFREQ_SHARED_TYPE_HW;
|
|
policy->cpuinfo.transition_latency = 100000; /* 100us */
|
|
|
|
return cpufreq_table_validate_and_show(policy, freq_table);
|
|
}
|
|
|
|
static struct cpufreq_driver sfi_cpufreq_driver = {
|
|
.flags = CPUFREQ_CONST_LOOPS,
|
|
.verify = cpufreq_generic_frequency_table_verify,
|
|
.target_index = sfi_cpufreq_target,
|
|
.init = sfi_cpufreq_cpu_init,
|
|
.name = "sfi-cpufreq",
|
|
.attr = cpufreq_generic_attr,
|
|
};
|
|
|
|
static int __init sfi_cpufreq_init(void)
|
|
{
|
|
int ret, i;
|
|
|
|
/* parse the freq table from SFI */
|
|
ret = sfi_table_parse(SFI_SIG_FREQ, NULL, NULL, sfi_parse_freq);
|
|
if (ret)
|
|
return ret;
|
|
|
|
freq_table = kzalloc(sizeof(*freq_table) *
|
|
(num_freq_table_entries + 1), GFP_KERNEL);
|
|
if (!freq_table) {
|
|
ret = -ENOMEM;
|
|
goto err_free_array;
|
|
}
|
|
|
|
for (i = 0; i < num_freq_table_entries; i++) {
|
|
freq_table[i].driver_data = i;
|
|
freq_table[i].frequency = sfi_cpufreq_array[i].freq_mhz * 1000;
|
|
}
|
|
freq_table[i].frequency = CPUFREQ_TABLE_END;
|
|
|
|
ret = cpufreq_register_driver(&sfi_cpufreq_driver);
|
|
if (ret)
|
|
goto err_free_tbl;
|
|
|
|
return ret;
|
|
|
|
err_free_tbl:
|
|
kfree(freq_table);
|
|
err_free_array:
|
|
kfree(sfi_cpufreq_array);
|
|
return ret;
|
|
}
|
|
late_initcall(sfi_cpufreq_init);
|
|
|
|
static void __exit sfi_cpufreq_exit(void)
|
|
{
|
|
cpufreq_unregister_driver(&sfi_cpufreq_driver);
|
|
kfree(freq_table);
|
|
kfree(sfi_cpufreq_array);
|
|
}
|
|
module_exit(sfi_cpufreq_exit);
|
|
|
|
MODULE_AUTHOR("Vishwesh M Rudramuni <vishwesh.m.rudramuni@intel.com>");
|
|
MODULE_DESCRIPTION("SFI Performance-States Driver");
|
|
MODULE_LICENSE("GPL");
|