/*
* Copyright 2013 Freescale Semiconductor, Inc.
*
* CPU Frequency Scaling driver for Freescale QorIQ SoCs.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.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>
#if !defined(CONFIG_ARM)
#include <asm/smp.h> /* for get_hard_smp_processor_id() in UP configs */
#endif
/**
* struct cpu_data
* @parent: the parent node of cpu clock
* @table: frequency table
*/
struct cpu_data {
struct device_node *parent;
struct cpufreq_frequency_table *table;
};
/**
* struct soc_data - SoC specific data
* @freq_mask: mask the disallowed frequencies
* @flag: unique flags
*/
struct soc_data {
u32 freq_mask[4];
u32 flag;
};
#define FREQ_MASK 1
/* see hardware specification for the allowed frqeuencies */
static const struct soc_data sdata[] = {
{ /* used by p2041 and p3041 */
.freq_mask = {0x8, 0x8, 0x2, 0x2},
.flag = FREQ_MASK,
},
{ /* used by p5020 */
.freq_mask = {0x8, 0x2},
.flag = FREQ_MASK,
},
{ /* used by p4080, p5040 */
.freq_mask = {0},
.flag = 0,
},
};
/*
* the minimum allowed core frequency, in Hz
* for chassis v1.0, >= platform frequency
* for chassis v2.0, >= platform frequency / 2
*/
static u32 min_cpufreq;
static const u32 *fmask;
#if defined(CONFIG_ARM)
static int get_cpu_physical_id(int cpu)
{
return topology_core_id(cpu);
}
#else
static int get_cpu_physical_id(int cpu)
{
return get_hard_smp_processor_id(cpu);
}
#endif
static u32 get_bus_freq(void)
{
struct device_node *soc;
u32 sysfreq;
soc = of_find_node_by_type(NULL, "soc");
if (!soc)
return 0;
if (of_property_read_u32(soc, "bus-frequency", &sysfreq))
sysfreq = 0;
of_node_put(soc);
return sysfreq;
}
static struct device_node *cpu_to_clk_node(int cpu)
{
struct device_node *np, *clk_np;
if (!cpu_present(cpu))
return NULL;
np = of_get_cpu_node(cpu, NULL);
if (!np)
return NULL;
clk_np = of_parse_phandle(np, "clocks", 0);
if (!clk_np)
return NULL;
of_node_put(np);
return clk_np;
}
/* traverse cpu nodes to get cpu mask of sharing clock wire */
static void set_affected_cpus(struct cpufreq_policy *policy)
{
struct device_node *np, *clk_np;
struct cpumask *dstp = policy->cpus;
int i;
np = cpu_to_clk_node(policy->cpu);
if (!np)
return;
for_each_present_cpu(i) {
clk_np = cpu_to_clk_node(i);
if (!clk_np)
continue;
if (clk_np == np)
cpumask_set_cpu(i, dstp);
of_node_put(clk_np);
}
of_node_put(np);
}
/* 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, ret;
u32 freq, mask;
struct clk *clk;
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;
}
data->parent = of_parse_phandle(np, "clocks", 0);
if (!data->parent) {
pr_err("%s: could not get clock information\n", __func__);
goto err_nomem2;
}
count = of_property_count_strings(data->parent, "clock-names");
table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
if (!table) {
pr_err("%s: no memory\n", __func__);
goto err_node;
}
if (fmask)
mask = fmask[get_cpu_physical_id(cpu)];
else
mask = 0x0;
for (i = 0; i < count; i++) {
clk = of_clk_get(data->parent, i);
freq = clk_get_rate(clk);
/*
* the clock is valid if its frequency is not masked
* and large than minimum allowed frequency.
*/
if (freq < min_cpufreq || (mask & (1 << i)))
table[i].frequency = CPUFREQ_ENTRY_INVALID;
else
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;
/* set the min and max frequency properly */
ret = cpufreq_table_validate_and_show(policy, table);
if (ret) {
pr_err("invalid frequency table: %d\n", ret);
goto err_nomem1;
}
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_nomem1:
kfree(table);
err_node:
of_node_put(data->parent);
err_nomem2:
policy->driver_data = NULL;
kfree(data);
err_np:
of_node_put(np);
return -ENODEV;
}
static int __exit qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
struct cpu_data *data = policy->driver_data;
of_node_put(data->parent);
kfree(data->table);
kfree(data);
policy->driver_data = NULL;
return 0;
}
static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
unsigned int index)
{
struct clk *parent;
struct cpu_data *data = policy->driver_data;
parent = of_clk_get(data->parent, 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,
.init = qoriq_cpufreq_cpu_init,
.exit = __exit_p(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 node_matches[] __initconst = {
{ .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
{ .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
{ .compatible = "fsl,p5020-clockgen", .data = &sdata[1], },
{ .compatible = "fsl,p4080-clockgen", .data = &sdata[2], },
{ .compatible = "fsl,p5040-clockgen", .data = &sdata[2], },
{ .compatible = "fsl,qoriq-clockgen-2.0", },
{}
};
static int __init qoriq_cpufreq_init(void)
{
int ret;
struct device_node *np;
const struct of_device_id *match;
const struct soc_data *data;
np = of_find_matching_node(NULL, node_matches);
if (!np)
return -ENODEV;
match = of_match_node(node_matches, np);
data = match->data;
if (data) {
if (data->flag)
fmask = data->freq_mask;
min_cpufreq = get_bus_freq();
} else {
min_cpufreq = get_bus_freq() / 2;
}
of_node_put(np);
ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
if (!ret)
pr_info("Freescale QorIQ CPU frequency scaling driver\n");
return ret;
}
module_init(qoriq_cpufreq_init);
static void __exit qoriq_cpufreq_exit(void)
{
cpufreq_unregister_driver(&qoriq_cpufreq_driver);
}
module_exit(qoriq_cpufreq_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");