s3c2410-cpufreq.c
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/*
* Copyright (c) 2006-2008 Simtec Electronics
* http://armlinux.simtec.co.uk/
* Ben Dooks <ben@simtec.co.uk>
*
* S3C2410 CPU Frequency scaling
*
* 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.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/cpufreq.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <asm/mach/arch.h>
#include <asm/mach/map.h>
#include <mach/regs-clock.h>
#include <plat/cpu.h>
#include <plat/cpu-freq-core.h>
/* Note, 2410A has an extra mode for 1:4:4 ratio, bit 2 of CLKDIV */
static void s3c2410_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
{
u32 clkdiv = 0;
if (cfg->divs.h_divisor == 2)
clkdiv |= S3C2410_CLKDIVN_HDIVN;
if (cfg->divs.p_divisor != cfg->divs.h_divisor)
clkdiv |= S3C2410_CLKDIVN_PDIVN;
__raw_writel(clkdiv, S3C2410_CLKDIVN);
}
static int s3c2410_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
{
unsigned long hclk, fclk, pclk;
unsigned int hdiv, pdiv;
unsigned long hclk_max;
fclk = cfg->freq.fclk;
hclk_max = cfg->max.hclk;
cfg->freq.armclk = fclk;
s3c_freq_dbg("%s: fclk is %lu, max hclk %lu\n",
__func__, fclk, hclk_max);
hdiv = (fclk > cfg->max.hclk) ? 2 : 1;
hclk = fclk / hdiv;
if (hclk > cfg->max.hclk) {
s3c_freq_dbg("%s: hclk too big\n", __func__);
return -EINVAL;
}
pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
pclk = hclk / pdiv;
if (pclk > cfg->max.pclk) {
s3c_freq_dbg("%s: pclk too big\n", __func__);
return -EINVAL;
}
pdiv *= hdiv;
/* record the result */
cfg->divs.p_divisor = pdiv;
cfg->divs.h_divisor = hdiv;
return 0;
}
static struct s3c_cpufreq_info s3c2410_cpufreq_info = {
.max = {
.fclk = 200000000,
.hclk = 100000000,
.pclk = 50000000,
},
/* transition latency is about 5ms worst-case, so
* set 10ms to be sure */
.latency = 10000000,
.locktime_m = 150,
.locktime_u = 150,
.locktime_bits = 12,
.need_pll = 1,
.name = "s3c2410",
.calc_iotiming = s3c2410_iotiming_calc,
.set_iotiming = s3c2410_iotiming_set,
.get_iotiming = s3c2410_iotiming_get,
.set_fvco = s3c2410_set_fvco,
.set_refresh = s3c2410_cpufreq_setrefresh,
.set_divs = s3c2410_cpufreq_setdivs,
.calc_divs = s3c2410_cpufreq_calcdivs,
.debug_io_show = s3c_cpufreq_debugfs_call(s3c2410_iotiming_debugfs),
};
static int s3c2410_cpufreq_add(struct device *dev,
struct subsys_interface *sif)
{
return s3c_cpufreq_register(&s3c2410_cpufreq_info);
}
static struct subsys_interface s3c2410_cpufreq_interface = {
.name = "s3c2410_cpufreq",
.subsys = &s3c2410_subsys,
.add_dev = s3c2410_cpufreq_add,
};
static int __init s3c2410_cpufreq_init(void)
{
return subsys_interface_register(&s3c2410_cpufreq_interface);
}
arch_initcall(s3c2410_cpufreq_init);
static int s3c2410a_cpufreq_add(struct device *dev,
struct subsys_interface *sif)
{
/* alter the maximum freq settings for S3C2410A. If a board knows
* it only has a maximum of 200, then it should register its own
* limits. */
s3c2410_cpufreq_info.max.fclk = 266000000;
s3c2410_cpufreq_info.max.hclk = 133000000;
s3c2410_cpufreq_info.max.pclk = 66500000;
s3c2410_cpufreq_info.name = "s3c2410a";
return s3c2410_cpufreq_add(dev, sif);
}
static struct subsys_interface s3c2410a_cpufreq_interface = {
.name = "s3c2410a_cpufreq",
.subsys = &s3c2410a_subsys,
.add_dev = s3c2410a_cpufreq_add,
};
static int __init s3c2410a_cpufreq_init(void)
{
return subsys_interface_register(&s3c2410a_cpufreq_interface);
}
arch_initcall(s3c2410a_cpufreq_init);