260 lines
6.3 KiB
C
260 lines
6.3 KiB
C
/*
|
|
* kirkwood_freq.c: cpufreq driver for the Marvell kirkwood
|
|
*
|
|
* Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>
|
|
*
|
|
* 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, or (at your option) any later version.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/clk-provider.h>
|
|
#include <linux/cpufreq.h>
|
|
#include <linux/of.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/io.h>
|
|
#include <asm/proc-fns.h>
|
|
|
|
#define CPU_SW_INT_BLK BIT(28)
|
|
|
|
static struct priv
|
|
{
|
|
struct clk *cpu_clk;
|
|
struct clk *ddr_clk;
|
|
struct clk *powersave_clk;
|
|
struct device *dev;
|
|
void __iomem *base;
|
|
} priv;
|
|
|
|
#define STATE_CPU_FREQ 0x01
|
|
#define STATE_DDR_FREQ 0x02
|
|
|
|
/*
|
|
* Kirkwood can swap the clock to the CPU between two clocks:
|
|
*
|
|
* - cpu clk
|
|
* - ddr clk
|
|
*
|
|
* The frequencies are set at runtime before registering this *
|
|
* table.
|
|
*/
|
|
static struct cpufreq_frequency_table kirkwood_freq_table[] = {
|
|
{STATE_CPU_FREQ, 0}, /* CPU uses cpuclk */
|
|
{STATE_DDR_FREQ, 0}, /* CPU uses ddrclk */
|
|
{0, CPUFREQ_TABLE_END},
|
|
};
|
|
|
|
static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu)
|
|
{
|
|
if (__clk_is_enabled(priv.powersave_clk))
|
|
return kirkwood_freq_table[1].frequency;
|
|
return kirkwood_freq_table[0].frequency;
|
|
}
|
|
|
|
static void kirkwood_cpufreq_set_cpu_state(unsigned int index)
|
|
{
|
|
struct cpufreq_freqs freqs;
|
|
unsigned int state = kirkwood_freq_table[index].index;
|
|
unsigned long reg;
|
|
|
|
freqs.old = kirkwood_cpufreq_get_cpu_frequency(0);
|
|
freqs.new = kirkwood_freq_table[index].frequency;
|
|
freqs.cpu = 0; /* Kirkwood is UP */
|
|
|
|
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
|
|
|
|
dev_dbg(priv.dev, "Attempting to set frequency to %i KHz\n",
|
|
kirkwood_freq_table[index].frequency);
|
|
dev_dbg(priv.dev, "old frequency was %i KHz\n",
|
|
kirkwood_cpufreq_get_cpu_frequency(0));
|
|
|
|
if (freqs.old != freqs.new) {
|
|
local_irq_disable();
|
|
|
|
/* Disable interrupts to the CPU */
|
|
reg = readl_relaxed(priv.base);
|
|
reg |= CPU_SW_INT_BLK;
|
|
writel_relaxed(reg, priv.base);
|
|
|
|
switch (state) {
|
|
case STATE_CPU_FREQ:
|
|
clk_disable(priv.powersave_clk);
|
|
break;
|
|
case STATE_DDR_FREQ:
|
|
clk_enable(priv.powersave_clk);
|
|
break;
|
|
}
|
|
|
|
/* Wait-for-Interrupt, while the hardware changes frequency */
|
|
cpu_do_idle();
|
|
|
|
/* Enable interrupts to the CPU */
|
|
reg = readl_relaxed(priv.base);
|
|
reg &= ~CPU_SW_INT_BLK;
|
|
writel_relaxed(reg, priv.base);
|
|
|
|
local_irq_enable();
|
|
}
|
|
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
|
|
};
|
|
|
|
static int kirkwood_cpufreq_verify(struct cpufreq_policy *policy)
|
|
{
|
|
return cpufreq_frequency_table_verify(policy, kirkwood_freq_table);
|
|
}
|
|
|
|
static int kirkwood_cpufreq_target(struct cpufreq_policy *policy,
|
|
unsigned int target_freq,
|
|
unsigned int relation)
|
|
{
|
|
unsigned int index = 0;
|
|
|
|
if (cpufreq_frequency_table_target(policy, kirkwood_freq_table,
|
|
target_freq, relation, &index))
|
|
return -EINVAL;
|
|
|
|
kirkwood_cpufreq_set_cpu_state(index);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Module init and exit code */
|
|
static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
|
|
{
|
|
int result;
|
|
|
|
/* cpuinfo and default policy values */
|
|
policy->cpuinfo.transition_latency = 5000; /* 5uS */
|
|
policy->cur = kirkwood_cpufreq_get_cpu_frequency(0);
|
|
|
|
result = cpufreq_frequency_table_cpuinfo(policy, kirkwood_freq_table);
|
|
if (result)
|
|
return result;
|
|
|
|
cpufreq_frequency_table_get_attr(kirkwood_freq_table, policy->cpu);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int kirkwood_cpufreq_cpu_exit(struct cpufreq_policy *policy)
|
|
{
|
|
cpufreq_frequency_table_put_attr(policy->cpu);
|
|
return 0;
|
|
}
|
|
|
|
static struct freq_attr *kirkwood_cpufreq_attr[] = {
|
|
&cpufreq_freq_attr_scaling_available_freqs,
|
|
NULL,
|
|
};
|
|
|
|
static struct cpufreq_driver kirkwood_cpufreq_driver = {
|
|
.get = kirkwood_cpufreq_get_cpu_frequency,
|
|
.verify = kirkwood_cpufreq_verify,
|
|
.target = kirkwood_cpufreq_target,
|
|
.init = kirkwood_cpufreq_cpu_init,
|
|
.exit = kirkwood_cpufreq_cpu_exit,
|
|
.name = "kirkwood-cpufreq",
|
|
.owner = THIS_MODULE,
|
|
.attr = kirkwood_cpufreq_attr,
|
|
};
|
|
|
|
static int kirkwood_cpufreq_probe(struct platform_device *pdev)
|
|
{
|
|
struct device_node *np;
|
|
struct resource *res;
|
|
int err;
|
|
|
|
priv.dev = &pdev->dev;
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
if (!res) {
|
|
dev_err(&pdev->dev, "Cannot get memory resource\n");
|
|
return -ENODEV;
|
|
}
|
|
priv.base = devm_request_and_ioremap(&pdev->dev, res);
|
|
if (!priv.base) {
|
|
dev_err(&pdev->dev, "Cannot ioremap\n");
|
|
return -EADDRNOTAVAIL;
|
|
}
|
|
|
|
np = of_find_node_by_path("/cpus/cpu@0");
|
|
if (!np)
|
|
return -ENODEV;
|
|
|
|
priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk");
|
|
if (IS_ERR(priv.cpu_clk)) {
|
|
dev_err(priv.dev, "Unable to get cpuclk");
|
|
return PTR_ERR(priv.cpu_clk);
|
|
}
|
|
|
|
clk_prepare_enable(priv.cpu_clk);
|
|
kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000;
|
|
|
|
priv.ddr_clk = of_clk_get_by_name(np, "ddrclk");
|
|
if (IS_ERR(priv.ddr_clk)) {
|
|
dev_err(priv.dev, "Unable to get ddrclk");
|
|
err = PTR_ERR(priv.ddr_clk);
|
|
goto out_cpu;
|
|
}
|
|
|
|
clk_prepare_enable(priv.ddr_clk);
|
|
kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000;
|
|
|
|
priv.powersave_clk = of_clk_get_by_name(np, "powersave");
|
|
if (IS_ERR(priv.powersave_clk)) {
|
|
dev_err(priv.dev, "Unable to get powersave");
|
|
err = PTR_ERR(priv.powersave_clk);
|
|
goto out_ddr;
|
|
}
|
|
clk_prepare(priv.powersave_clk);
|
|
|
|
of_node_put(np);
|
|
np = NULL;
|
|
|
|
err = cpufreq_register_driver(&kirkwood_cpufreq_driver);
|
|
if (!err)
|
|
return 0;
|
|
|
|
dev_err(priv.dev, "Failed to register cpufreq driver");
|
|
|
|
clk_disable_unprepare(priv.powersave_clk);
|
|
out_ddr:
|
|
clk_disable_unprepare(priv.ddr_clk);
|
|
out_cpu:
|
|
clk_disable_unprepare(priv.cpu_clk);
|
|
of_node_put(np);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int kirkwood_cpufreq_remove(struct platform_device *pdev)
|
|
{
|
|
cpufreq_unregister_driver(&kirkwood_cpufreq_driver);
|
|
|
|
clk_disable_unprepare(priv.powersave_clk);
|
|
clk_disable_unprepare(priv.ddr_clk);
|
|
clk_disable_unprepare(priv.cpu_clk);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver kirkwood_cpufreq_platform_driver = {
|
|
.probe = kirkwood_cpufreq_probe,
|
|
.remove = kirkwood_cpufreq_remove,
|
|
.driver = {
|
|
.name = "kirkwood-cpufreq",
|
|
.owner = THIS_MODULE,
|
|
},
|
|
};
|
|
|
|
module_platform_driver(kirkwood_cpufreq_platform_driver);
|
|
|
|
MODULE_LICENSE("GPL v2");
|
|
MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");
|
|
MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU");
|
|
MODULE_ALIAS("platform:kirkwood-cpufreq");
|