// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2013 Freescale Semiconductor, Inc.
*
* CPU Frequency Scaling driver for Freescale QorIQ SoCs.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/cpufreq.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/platform_device.h>
/**
* struct cpu_data
* @pclk: the parent clock of cpu
* @table: frequency table
*/
struct cpu_data {
struct clk **pclk;
struct cpufreq_frequency_table *table;
};
/**
* struct soc_data - SoC specific data
* @flags: SOC_xxx
*/
struct soc_data {
u32 flags;
};
static u32 get_bus_freq(void)
{
struct device_node *soc;
u32 sysfreq;
struct clk *pltclk;
int ret;
/* get platform freq by searching bus-frequency property */
soc = of_find_node_by_type(NULL, "soc");
if (soc) {
ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
of_node_put(soc);
if (!ret)
return sysfreq;
}
/* get platform freq by its clock name */
pltclk = clk_get(NULL, "cg-pll0-div1");
if (IS_ERR(pltclk)) {
pr_err("%s: can't get bus frequency %ld\n",
__func__, PTR_ERR(pltclk));
return PTR_ERR(pltclk);
}
return clk_get_rate(pltclk);
}
static struct clk *cpu_to_clk(int cpu)
{
struct device_node *np;
struct clk *clk;
if (!cpu_present(cpu))
return NULL;
np = of_get_cpu_node(cpu, NULL);
if (!np)
return NULL;
clk = of_clk_get(np, 0);
of_node_put(np);
return clk;
}
/* traverse cpu nodes to get cpu mask of sharing clock wire */
static void set_affected_cpus(struct cpufreq_policy *policy)
{
struct cpumask *dstp = policy->cpus;
struct clk *clk;
int i;
for_each_present_cpu(i) {
clk = cpu_to_clk(i);
if (IS_ERR(clk)) {
pr_err("%s: no clock for cpu %d\n", __func__, i);
continue;
}
if (clk_is_match(policy->clk, clk))
cpumask_set_cpu(i, dstp);
}
}
/* reduce the duplicated frequencies in frequency table */
static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
int count)
{
int i, j;
for (i = 1; i < count; i++) {
for (j = 0; j < i; j++) {
if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
freq_table[j].frequency !=
freq_table[i].frequency)
continue;
freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
break;
}
}
}
/* sort the frequencies in frequency table in descenting order */
static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
int count)
{
int i, j, ind;
unsigned int freq, max_freq;
struct cpufreq_frequency_table table;
for (i = 0; i < count - 1; i++) {
max_freq = freq_table[i].frequency;
ind = i;
for (j = i + 1; j < count; j++) {
freq = freq_table[j].frequency;
if (freq == CPUFREQ_ENTRY_INVALID ||
freq <= max_freq)
continue;
ind = j;
max_freq = freq;
}
if (ind != i) {
/* exchange the frequencies */
table.driver_data = freq_table[i].driver_data;
table.frequency = freq_table[i].frequency;
freq_table[i].driver_data = freq_table[ind].driver_data;
freq_table[i].frequency = freq_table[ind].frequency;
freq_table[ind].driver_data = table.driver_data;
freq_table[ind].frequency = table.frequency;
}
}
}
static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
struct device_node *np;
int i, count;
u32 freq;
struct clk *clk;
const struct clk_hw *hwclk;
struct cpufreq_frequency_table *table;
struct cpu_data *data;
unsigned int cpu = policy->cpu;
u64 u64temp;
np = of_get_cpu_node(cpu, NULL);
if (!np)
return -ENODEV;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
goto err_np;
policy->clk = of_clk_get(np, 0);
if (IS_ERR(policy->clk)) {
pr_err("%s: no clock information\n", __func__);
goto err_nomem2;
}
hwclk = __clk_get_hw(policy->clk);
count = clk_hw_get_num_parents(hwclk);
data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
if (!data->pclk)
goto err_nomem2;
table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
if (!table)
goto err_pclk;
for (i = 0; i < count; i++) {
clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
data->pclk[i] = clk;
freq = clk_get_rate(clk);
table[i].frequency = freq / 1000;
table[i].driver_data = i;
}
freq_table_redup(table, count);
freq_table_sort(table, count);
table[i].frequency = CPUFREQ_TABLE_END;
policy->freq_table = table;
data->table = table;
/* update ->cpus if we have cluster, no harm if not */
set_affected_cpus(policy);
policy->driver_data = data;
/* Minimum transition latency is 12 platform clocks */
u64temp = 12ULL * NSEC_PER_SEC;
do_div(u64temp, get_bus_freq());
policy->cpuinfo.transition_latency = u64temp + 1;
of_node_put(np);
return 0;
err_pclk:
kfree(data->pclk);
err_nomem2:
kfree(data);
err_np:
of_node_put(np);
return -ENODEV;
}
static void qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
struct cpu_data *data = policy->driver_data;
kfree(data->pclk);
kfree(data->table);
kfree(data);
policy->driver_data = NULL;
}
static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
unsigned int index)
{
struct clk *parent;
struct cpu_data *data = policy->driver_data;
parent = data->pclk[data->table[index].driver_data];
return clk_set_parent(policy->clk, parent);
}
static struct cpufreq_driver qoriq_cpufreq_driver = {
.name = "qoriq_cpufreq",
.flags = CPUFREQ_CONST_LOOPS |
CPUFREQ_IS_COOLING_DEV,
.init = qoriq_cpufreq_cpu_init,
.exit = qoriq_cpufreq_cpu_exit,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = qoriq_cpufreq_target,
.get = cpufreq_generic_get,
.attr = cpufreq_generic_attr,
};
static const struct of_device_id qoriq_cpufreq_blacklist[] = {
/* e6500 cannot use cpufreq due to erratum A-008083 */
{ .compatible = "fsl,b4420-clockgen", },
{ .compatible = "fsl,b4860-clockgen", },
{ .compatible = "fsl,t2080-clockgen", },
{ .compatible = "fsl,t4240-clockgen", },
{}
};
static int qoriq_cpufreq_probe(struct platform_device *pdev)
{
int ret;
struct device_node *np;
np = of_find_matching_node(NULL, qoriq_cpufreq_blacklist);
if (np) {
of_node_put(np);
dev_info(&pdev->dev, "Disabling due to erratum A-008083");
return -ENODEV;
}
ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
if (ret)
return ret;
dev_info(&pdev->dev, "Freescale QorIQ CPU frequency scaling driver\n");
return 0;
}
static void qoriq_cpufreq_remove(struct platform_device *pdev)
{
cpufreq_unregister_driver(&qoriq_cpufreq_driver);
}
static struct platform_driver qoriq_cpufreq_platform_driver = {
.driver = {
.name = "qoriq-cpufreq",
},
.probe = qoriq_cpufreq_probe,
.remove_new = qoriq_cpufreq_remove,
};
module_platform_driver(qoriq_cpufreq_platform_driver);
MODULE_ALIAS("platform:qoriq-cpufreq");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Tang Yuantian <[email protected]>");
MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");
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