linux/drivers/cpufreq/kirkwood-cpufreq.c

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/*
* 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/cpufreq.h>
#include <linux/of_device.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[] = {
{0, STATE_CPU_FREQ, 0}, /* CPU uses cpuclk */
{0, STATE_DDR_FREQ, 0}, /* CPU uses ddrclk */
{0, 0, CPUFREQ_TABLE_END},
};
static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu)
{
return clk_get_rate(priv.powersave_clk) / 1000;
}
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 14:15:48 +00:00
static int kirkwood_cpufreq_target(struct cpufreq_policy *policy,
unsigned int index)
{
unsigned int state = kirkwood_freq_table[index].driver_data;
unsigned long reg;
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_set_parent(priv.powersave_clk, priv.cpu_clk);
break;
case STATE_DDR_FREQ:
clk_set_parent(priv.powersave_clk, priv.ddr_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();
return 0;
}
/* Module init and exit code */
static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
return cpufreq_generic_init(policy, kirkwood_freq_table, 5000);
}
static struct cpufreq_driver kirkwood_cpufreq_driver = {
.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.get = kirkwood_cpufreq_get_cpu_frequency,
.verify = cpufreq_generic_frequency_table_verify,
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 14:15:48 +00:00
.target_index = kirkwood_cpufreq_target,
.init = kirkwood_cpufreq_cpu_init,
.name = "kirkwood-cpufreq",
.attr = cpufreq_generic_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);
priv.base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv.base))
return PTR_ERR(priv.base);
np = of_cpu_device_node_get(0);
if (!np) {
dev_err(&pdev->dev, "failed to get cpu device node\n");
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\n");
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\n");
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\n");
err = PTR_ERR(priv.powersave_clk);
goto out_ddr;
}
clk_prepare_enable(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\n");
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",
},
};
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");