forked from Minki/linux
cdb56cbfd7
Add the MIPS CPUfreq driver. This driver currently supports CPUfreq on BMIPS5xxx-based SoCs. Signed-off-by: Markus Mayer <mmayer@broadcom.com> Acked-by: Florian Fainelli <f.fainelli@gmail.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
189 lines
4.3 KiB
C
189 lines
4.3 KiB
C
/*
|
|
* CPU frequency scaling for Broadcom BMIPS SoCs
|
|
*
|
|
* Copyright (c) 2017 Broadcom
|
|
*
|
|
* 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 version 2.
|
|
*
|
|
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
|
|
* kind, whether express or implied; without even the implied warranty
|
|
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*/
|
|
|
|
#include <linux/cpufreq.h>
|
|
#include <linux/module.h>
|
|
#include <linux/of_address.h>
|
|
#include <linux/slab.h>
|
|
|
|
/* for mips_hpt_frequency */
|
|
#include <asm/time.h>
|
|
|
|
#define BMIPS_CPUFREQ_PREFIX "bmips"
|
|
#define BMIPS_CPUFREQ_NAME BMIPS_CPUFREQ_PREFIX "-cpufreq"
|
|
|
|
#define TRANSITION_LATENCY (25 * 1000) /* 25 us */
|
|
|
|
#define BMIPS5_CLK_DIV_SET_SHIFT 0x7
|
|
#define BMIPS5_CLK_DIV_SHIFT 0x4
|
|
#define BMIPS5_CLK_DIV_MASK 0xf
|
|
|
|
enum bmips_type {
|
|
BMIPS5000,
|
|
BMIPS5200,
|
|
};
|
|
|
|
struct cpufreq_compat {
|
|
const char *compatible;
|
|
unsigned int bmips_type;
|
|
unsigned int clk_mult;
|
|
unsigned int max_freqs;
|
|
};
|
|
|
|
#define BMIPS(c, t, m, f) { \
|
|
.compatible = c, \
|
|
.bmips_type = (t), \
|
|
.clk_mult = (m), \
|
|
.max_freqs = (f), \
|
|
}
|
|
|
|
static struct cpufreq_compat bmips_cpufreq_compat[] = {
|
|
BMIPS("brcm,bmips5000", BMIPS5000, 8, 4),
|
|
BMIPS("brcm,bmips5200", BMIPS5200, 8, 4),
|
|
{ }
|
|
};
|
|
|
|
static struct cpufreq_compat *priv;
|
|
|
|
static int htp_freq_to_cpu_freq(unsigned int clk_mult)
|
|
{
|
|
return mips_hpt_frequency * clk_mult / 1000;
|
|
}
|
|
|
|
static struct cpufreq_frequency_table *
|
|
bmips_cpufreq_get_freq_table(const struct cpufreq_policy *policy)
|
|
{
|
|
struct cpufreq_frequency_table *table;
|
|
unsigned long cpu_freq;
|
|
int i;
|
|
|
|
cpu_freq = htp_freq_to_cpu_freq(priv->clk_mult);
|
|
|
|
table = kmalloc((priv->max_freqs + 1) * sizeof(*table), GFP_KERNEL);
|
|
if (!table)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
for (i = 0; i < priv->max_freqs; i++) {
|
|
table[i].frequency = cpu_freq / (1 << i);
|
|
table[i].driver_data = i;
|
|
}
|
|
table[i].frequency = CPUFREQ_TABLE_END;
|
|
|
|
return table;
|
|
}
|
|
|
|
static unsigned int bmips_cpufreq_get(unsigned int cpu)
|
|
{
|
|
unsigned int div;
|
|
uint32_t mode;
|
|
|
|
switch (priv->bmips_type) {
|
|
case BMIPS5200:
|
|
case BMIPS5000:
|
|
mode = read_c0_brcm_mode();
|
|
div = ((mode >> BMIPS5_CLK_DIV_SHIFT) & BMIPS5_CLK_DIV_MASK);
|
|
break;
|
|
default:
|
|
div = 0;
|
|
}
|
|
|
|
return htp_freq_to_cpu_freq(priv->clk_mult) / (1 << div);
|
|
}
|
|
|
|
static int bmips_cpufreq_target_index(struct cpufreq_policy *policy,
|
|
unsigned int index)
|
|
{
|
|
unsigned int div = policy->freq_table[index].driver_data;
|
|
|
|
switch (priv->bmips_type) {
|
|
case BMIPS5200:
|
|
case BMIPS5000:
|
|
change_c0_brcm_mode(BMIPS5_CLK_DIV_MASK << BMIPS5_CLK_DIV_SHIFT,
|
|
(1 << BMIPS5_CLK_DIV_SET_SHIFT) |
|
|
(div << BMIPS5_CLK_DIV_SHIFT));
|
|
break;
|
|
default:
|
|
return -ENOTSUPP;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int bmips_cpufreq_exit(struct cpufreq_policy *policy)
|
|
{
|
|
kfree(policy->freq_table);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int bmips_cpufreq_init(struct cpufreq_policy *policy)
|
|
{
|
|
struct cpufreq_frequency_table *freq_table;
|
|
int ret;
|
|
|
|
freq_table = bmips_cpufreq_get_freq_table(policy);
|
|
if (IS_ERR(freq_table)) {
|
|
ret = PTR_ERR(freq_table);
|
|
pr_err("%s: couldn't determine frequency table (%d).\n",
|
|
BMIPS_CPUFREQ_NAME, ret);
|
|
return ret;
|
|
}
|
|
|
|
ret = cpufreq_generic_init(policy, freq_table, TRANSITION_LATENCY);
|
|
if (ret)
|
|
bmips_cpufreq_exit(policy);
|
|
else
|
|
pr_info("%s: registered\n", BMIPS_CPUFREQ_NAME);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static struct cpufreq_driver bmips_cpufreq_driver = {
|
|
.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
|
|
.verify = cpufreq_generic_frequency_table_verify,
|
|
.target_index = bmips_cpufreq_target_index,
|
|
.get = bmips_cpufreq_get,
|
|
.init = bmips_cpufreq_init,
|
|
.exit = bmips_cpufreq_exit,
|
|
.attr = cpufreq_generic_attr,
|
|
.name = BMIPS_CPUFREQ_PREFIX,
|
|
};
|
|
|
|
static int __init bmips_cpufreq_probe(void)
|
|
{
|
|
struct cpufreq_compat *cc;
|
|
struct device_node *np;
|
|
|
|
for (cc = bmips_cpufreq_compat; cc->compatible; cc++) {
|
|
np = of_find_compatible_node(NULL, "cpu", cc->compatible);
|
|
if (np) {
|
|
of_node_put(np);
|
|
priv = cc;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* We hit the guard element of the array. No compatible CPU found. */
|
|
if (!cc->compatible)
|
|
return -ENODEV;
|
|
|
|
return cpufreq_register_driver(&bmips_cpufreq_driver);
|
|
}
|
|
device_initcall(bmips_cpufreq_probe);
|
|
|
|
MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
|
|
MODULE_DESCRIPTION("CPUfreq driver for Broadcom BMIPS SoCs");
|
|
MODULE_LICENSE("GPL");
|