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ARM: S3C2410: CPUFREQ: Add core support. 

Add core support for frequency scaling on the S3C2410 SoC.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Ben Dooks 2009-07-30 23:23:27 +01:00 committed by Ben Dooks
parent 831a6fcb93
commit a24c091db9
6 changed files with 241 additions and 0 deletions
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11
arch/arm/mach-s3c2410/Kconfig
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@ -12,6 +12,7 @@ config CPU_S3C2410
select S3C2410_GPIO
select CPU_LLSERIAL_S3C2410
select S3C2410_PM if PM
select S3C2410_CPUFREQ if CPU_FREQ_S3C24XX
help
Support for S3C2410 and S3C2410A family from the S3C24XX line
of Samsung Mobile CPUs.
@ -45,6 +46,15 @@ config MACH_BAST_IDE
Internal node for machines with an BAST style IDE
interface
# cpu frequency scaling support
config S3C2410_CPUFREQ
bool
depends on CPU_FREQ_S3C24XX && CPU_S3C2410
select S3C2410_CPUFREQ_UTILS
help
CPU Frequency scaling support for S3C2410
menu "S3C2410 Machines"
config ARCH_SMDK2410
@ -79,6 +89,7 @@ config MACH_N30
config ARCH_BAST
bool "Simtec Electronics BAST (EB2410ITX)"
select CPU_S3C2410
select S3C2410_IOTIMING if S3C2410_CPUFREQ
select PM_SIMTEC if PM
select SIMTEC_NOR
select MACH_BAST_IDE

1
arch/arm/mach-s3c2410/Makefile
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@ -15,6 +15,7 @@ obj-$(CONFIG_CPU_S3C2410_DMA) += dma.o
obj-$(CONFIG_CPU_S3C2410_DMA) += dma.o
obj-$(CONFIG_S3C2410_PM) += pm.o sleep.o
obj-$(CONFIG_S3C2410_GPIO) += gpio.o
obj-$(CONFIG_S3C2410_CPUFREQ) += cpu-freq.o
# Machine support

157
arch/arm/mach-s3c2410/cpu-freq.c Normal file
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@ -0,0 +1,157 @@
/* linux/arch/arm/mach-s3c2410/cpu-freq.c
*
* 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/sysdev.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/clock.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,
.resume_clocks = s3c2410_setup_clocks,
.set_fvco = s3c2410_set_fvco,
.set_refresh = s3c2410_cpufreq_setrefresh,
.set_divs = s3c2410_cpufreq_setdivs,
.calc_divs = s3c2410_cpufreq_calcdivs,
};
static int s3c2410_cpufreq_add(struct sys_device *sysdev)
{
return s3c_cpufreq_register(&s3c2410_cpufreq_info);
}
static struct sysdev_driver s3c2410_cpufreq_driver = {
.add = s3c2410_cpufreq_add,
};
static int __init s3c2410_cpufreq_init(void)
{
return sysdev_driver_register(&s3c2410_sysclass,
&s3c2410_cpufreq_driver);
}
arch_initcall(s3c2410_cpufreq_init);
static int s3c2410a_cpufreq_add(struct sys_device *sysdev)
{
/* 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(sysdev);
}
static struct sysdev_driver s3c2410a_cpufreq_driver = {
.add = s3c2410a_cpufreq_add,
};
static int __init s3c2410a_cpufreq_init(void)
{
return sysdev_driver_register(&s3c2410a_sysclass,
&s3c2410a_cpufreq_driver);
}
arch_initcall(s3c2410a_cpufreq_init);

7
arch/arm/plat-s3c24xx/Kconfig
View File

@ -116,6 +116,13 @@ config S3C2410_IOTIMING
Internal node to select io timing code that is common to the s3c2410
and s3c2440/s3c2442 cpu frequency support.
config S3C2410_CPUFREQ_UTILS
bool
depends on CPU_FREQ_S3C24XX
help
Internal node to select timing code that is common to the s3c2410
and s3c2440/s3c244 cpu frequency support.
config MACH_SMDK
bool
help

1
arch/arm/plat-s3c24xx/Makefile
View File

@ -36,6 +36,7 @@ obj-$(CONFIG_S3C2410_CLOCK) += s3c2410-clock.o
obj-$(CONFIG_S3C2410_DMA) += dma.o
obj-$(CONFIG_S3C24XX_ADC) += adc.o
obj-$(CONFIG_S3C2410_IOTIMING) += s3c2410-iotiming.o
obj-$(CONFIG_S3C2410_CPUFREQ_UTILS) += s3c2410-cpufreq-utils.o
# device specific setup and/or initialisation
obj-$(CONFIG_ARCH_S3C2410) += setup-i2c.o

64
arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c Normal file
View File

@ -0,0 +1,64 @@
/* linux/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c
*
* Copyright (c) 2009 Simtec Electronics
* http://armlinux.simtec.co.uk/
* Ben Dooks <ben@simtec.co.uk>
*
* S3C24XX CPU Frequency scaling - utils for S3C2410/S3C2440/S3C2442
*
* 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/kernel.h>
#include <linux/errno.h>
#include <linux/cpufreq.h>
#include <linux/io.h>
#include <mach/map.h>
#include <mach/regs-mem.h>
#include <mach/regs-clock.h>
#include <plat/cpu-freq-core.h>
/**
* s3c2410_cpufreq_setrefresh - set SDRAM refresh value
* @cfg: The frequency configuration
*
* Set the SDRAM refresh value appropriately for the configured
* frequency.
*/
void s3c2410_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
{
struct s3c_cpufreq_board *board = cfg->board;
unsigned long refresh;
unsigned long refval;
/* Reduce both the refresh time (in ns) and the frequency (in MHz)
* down to ensure that we do not overflow 32 bit numbers.
*
* This should work for HCLK up to 133MHz and refresh period up
* to 30usec.
*/
refresh = (cfg->freq.hclk / 100) * (board->refresh / 10);
refresh = DIV_ROUND_UP(refresh, (1000 * 1000)); /* apply scale */
refresh = (1 << 11) + 1 - refresh;
s3c_freq_dbg("%s: refresh value %lu\n", __func__, refresh);
refval = __raw_readl(S3C2410_REFRESH);
refval &= ~((1 << 12) - 1);
refval |= refresh;
__raw_writel(refval, S3C2410_REFRESH);
}
/**
* s3c2410_set_fvco - set the PLL value
* @cfg: The frequency configuration
*/
void s3c2410_set_fvco(struct s3c_cpufreq_config *cfg)
{
__raw_writel(cfg->pll.index, S3C2410_MPLLCON);
}