cpufreq: s3c24xx: move cpufreq driver to drivers/cpufreq

This patch moves cpufreq driver of Samsung's ARM based
s3c24xx platform to drivers/cpufreq.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

7 files changed, 1701 insertions, 0 deletions

diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index f3af18b9acc5..bbcd7199257b 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -95,6 +95,56 @@ config ARM_OMAP2PLUS_CPUFREQ
 	default ARCH_OMAP2PLUS
 	select CPU_FREQ_TABLE
 
+config ARM_S3C_CPUFREQ
+	bool
+	help
+	  Internal configuration node for common cpufreq on Samsung SoC
+
+config ARM_S3C24XX_CPUFREQ
+	bool "CPUfreq driver for Samsung S3C24XX series CPUs (EXPERIMENTAL)"
+	depends on ARCH_S3C24XX
+	select ARM_S3C_CPUFREQ
+	help
+	  This enables the CPUfreq driver for the Samsung S3C24XX family
+	  of CPUs.
+
+	  For details, take a look at <file:Documentation/cpu-freq>.
+
+	  If in doubt, say N.
+
+config ARM_S3C24XX_CPUFREQ_DEBUG
+	bool "Debug CPUfreq Samsung driver core"
+	depends on ARM_S3C24XX_CPUFREQ
+	help
+	  Enable s3c_freq_dbg for the Samsung S3C CPUfreq core
+
+config ARM_S3C24XX_CPUFREQ_IODEBUG
+	bool "Debug CPUfreq Samsung driver IO timing"
+	depends on ARM_S3C24XX_CPUFREQ
+	help
+	  Enable s3c_freq_iodbg for the Samsung S3C CPUfreq core
+
+config ARM_S3C24XX_CPUFREQ_DEBUGFS
+	bool "Export debugfs for CPUFreq"
+	depends on ARM_S3C24XX_CPUFREQ && DEBUG_FS
+	help
+	  Export status information via debugfs.
+
+config ARM_S3C2410_CPUFREQ
+	bool
+	depends on ARM_S3C24XX_CPUFREQ && CPU_S3C2410
+	select S3C2410_CPUFREQ_UTILS
+	help
+	  CPU Frequency scaling support for S3C2410
+
+config ARM_S3C2412_CPUFREQ
+	bool
+	depends on ARM_S3C24XX_CPUFREQ && CPU_S3C2412
+	default y
+	select S3C2412_IOTIMING
+	help
+	  CPU Frequency scaling support for S3C2412 and S3C2413 SoC CPUs.
+
 config ARM_S3C2416_CPUFREQ
 	bool "S3C2416 CPU Frequency scaling support"
 	depends on CPU_S3C2416
@@ -117,6 +167,14 @@ config ARM_S3C2416_CPUFREQ_VCORESCALE
 
 	  If in doubt, say N.
 
+config ARM_S3C2440_CPUFREQ
+	bool "S3C2440/S3C2442 CPU Frequency scaling support"
+	depends on ARM_S3C24XX_CPUFREQ && (CPU_S3C2440 || CPU_S3C2442)
+	select S3C2410_CPUFREQ_UTILS
+	default y
+	help
+	  CPU Frequency scaling support for S3C2440 and S3C2442 SoC CPUs.
+
 config ARM_S3C64XX_CPUFREQ
 	bool "Samsung S3C64XX"
 	depends on CPU_S3C6410
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 315b9231feb1..6ad0b913ca17 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -65,7 +65,12 @@ obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ)	+= omap-cpufreq.o
 obj-$(CONFIG_PXA25x)			+= pxa2xx-cpufreq.o
 obj-$(CONFIG_PXA27x)			+= pxa2xx-cpufreq.o
 obj-$(CONFIG_PXA3xx)			+= pxa3xx-cpufreq.o
+obj-$(CONFIG_ARM_S3C24XX_CPUFREQ)	+= s3c24xx-cpufreq.o
+obj-$(CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS) += s3c24xx-cpufreq-debugfs.o
+obj-$(CONFIG_ARM_S3C2410_CPUFREQ)	+= s3c2410-cpufreq.o
+obj-$(CONFIG_ARM_S3C2412_CPUFREQ)	+= s3c2412-cpufreq.o
 obj-$(CONFIG_ARM_S3C2416_CPUFREQ)	+= s3c2416-cpufreq.o
+obj-$(CONFIG_ARM_S3C2440_CPUFREQ)	+= s3c2440-cpufreq.o
 obj-$(CONFIG_ARM_S3C64XX_CPUFREQ)	+= s3c64xx-cpufreq.o
 obj-$(CONFIG_ARM_S5PV210_CPUFREQ)	+= s5pv210-cpufreq.o
 obj-$(CONFIG_ARM_SA1100_CPUFREQ)	+= sa1100-cpufreq.o
diff --git a/drivers/cpufreq/s3c2410-cpufreq.c b/drivers/cpufreq/s3c2410-cpufreq.c
new file mode 100644
index 000000000000..cfa0dd8723ec
--- /dev/null
+++ b/drivers/cpufreq/s3c2410-cpufreq.c
@@ -0,0 +1,160 @@
+/*
+ * 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/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,
+
+	.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);
diff --git a/drivers/cpufreq/s3c2412-cpufreq.c b/drivers/cpufreq/s3c2412-cpufreq.c
new file mode 100644
index 000000000000..4645b4898996
--- /dev/null
+++ b/drivers/cpufreq/s3c2412-cpufreq.c
@@ -0,0 +1,257 @@
+/*
+ * Copyright 2008 Simtec Electronics
+ *	http://armlinux.simtec.co.uk/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C2412 CPU Frequency scalling
+ *
+ * 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/delay.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 <mach/s3c2412.h>
+
+#include <plat/cpu.h>
+#include <plat/clock.h>
+#include <plat/cpu-freq-core.h>
+
+/* our clock resources. */
+static struct clk *xtal;
+static struct clk *fclk;
+static struct clk *hclk;
+static struct clk *armclk;
+
+/* HDIV: 1, 2, 3, 4, 6, 8 */
+
+static int s3c2412_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
+{
+	unsigned int hdiv, pdiv, armdiv, dvs;
+	unsigned long hclk, fclk, armclk, armdiv_clk;
+	unsigned long hclk_max;
+
+	fclk = cfg->freq.fclk;
+	armclk = cfg->freq.armclk;
+	hclk_max = cfg->max.hclk;
+
+	/* We can't run hclk above armclk as at the best we have to
+	 * have armclk and hclk in dvs mode. */
+
+	if (hclk_max > armclk)
+		hclk_max = armclk;
+
+	s3c_freq_dbg("%s: fclk=%lu, armclk=%lu, hclk_max=%lu\n",
+		     __func__, fclk, armclk, hclk_max);
+	s3c_freq_dbg("%s: want f=%lu, arm=%lu, h=%lu, p=%lu\n",
+		     __func__, cfg->freq.fclk, cfg->freq.armclk,
+		     cfg->freq.hclk, cfg->freq.pclk);
+
+	armdiv = fclk / armclk;
+
+	if (armdiv < 1)
+		armdiv = 1;
+	if (armdiv > 2)
+		armdiv = 2;
+
+	cfg->divs.arm_divisor = armdiv;
+	armdiv_clk = fclk / armdiv;
+
+	hdiv = armdiv_clk / hclk_max;
+	if (hdiv < 1)
+		hdiv = 1;
+
+	cfg->freq.hclk = hclk = armdiv_clk / hdiv;
+
+	/* set dvs depending on whether we reached armclk or not. */
+	cfg->divs.dvs = dvs = armclk < armdiv_clk;
+
+	/* update the actual armclk we achieved. */
+	cfg->freq.armclk = dvs ? hclk : armdiv_clk;
+
+	s3c_freq_dbg("%s: armclk %lu, hclk %lu, armdiv %d, hdiv %d, dvs %d\n",
+		     __func__, armclk, hclk, armdiv, hdiv, cfg->divs.dvs);
+
+	if (hdiv > 4)
+		goto invalid;
+
+	pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
+
+	if ((hclk / pdiv) > cfg->max.pclk)
+		pdiv++;
+
+	cfg->freq.pclk = hclk / pdiv;
+
+	s3c_freq_dbg("%s: pdiv %d\n", __func__, pdiv);
+
+	if (pdiv > 2)
+		goto invalid;
+
+	pdiv *= hdiv;
+
+	/* store the result, and then return */
+
+	cfg->divs.h_divisor = hdiv * armdiv;
+	cfg->divs.p_divisor = pdiv * armdiv;
+
+	return 0;
+
+invalid:
+	return -EINVAL;
+}
+
+static void s3c2412_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
+{
+	unsigned long clkdiv;
+	unsigned long olddiv;
+
+	olddiv = clkdiv = __raw_readl(S3C2410_CLKDIVN);
+
+	/* clear off current clock info */
+
+	clkdiv &= ~S3C2412_CLKDIVN_ARMDIVN;
+	clkdiv &= ~S3C2412_CLKDIVN_HDIVN_MASK;
+	clkdiv &= ~S3C2412_CLKDIVN_PDIVN;
+
+	if (cfg->divs.arm_divisor == 2)
+		clkdiv |= S3C2412_CLKDIVN_ARMDIVN;
+
+	clkdiv |= ((cfg->divs.h_divisor / cfg->divs.arm_divisor) - 1);
+
+	if (cfg->divs.p_divisor != cfg->divs.h_divisor)
+		clkdiv |= S3C2412_CLKDIVN_PDIVN;
+
+	s3c_freq_dbg("%s: div %08lx => %08lx\n", __func__, olddiv, clkdiv);
+	__raw_writel(clkdiv, S3C2410_CLKDIVN);
+
+	clk_set_parent(armclk, cfg->divs.dvs ? hclk : fclk);
+}
+
+static void s3c2412_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
+{
+	struct s3c_cpufreq_board *board = cfg->board;
+	unsigned long refresh;
+
+	s3c_freq_dbg("%s: refresh %u ns, hclk %lu\n", __func__,
+		     board->refresh, cfg->freq.hclk);
+
+	/* Reduce both the refresh time (in ns) and the frequency (in MHz)
+	 * by 10 each 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 = (board->refresh / 10);
+	refresh *= (cfg->freq.hclk / 100);
+	refresh /= (1 * 1000 * 1000);	/* 10^6 */
+
+	s3c_freq_dbg("%s: setting refresh 0x%08lx\n", __func__, refresh);
+	__raw_writel(refresh, S3C2412_REFRESH);
+}
+
+/* set the default cpu frequency information, based on an 200MHz part
+ * as we have no other way of detecting the speed rating in software.
+ */
+
+static struct s3c_cpufreq_info s3c2412_cpufreq_info = {
+	.max		= {
+		.fclk	= 200000000,
+		.hclk	= 100000000,
+		.pclk	=  50000000,
+	},
+
+	.latency	= 5000000, /* 5ms */
+
+	.locktime_m	= 150,
+	.locktime_u	= 150,
+	.locktime_bits	= 16,
+
+	.name		= "s3c2412",
+	.set_refresh	= s3c2412_cpufreq_setrefresh,
+	.set_divs	= s3c2412_cpufreq_setdivs,
+	.calc_divs	= s3c2412_cpufreq_calcdivs,
+
+	.calc_iotiming	= s3c2412_iotiming_calc,
+	.set_iotiming	= s3c2412_iotiming_set,
+	.get_iotiming	= s3c2412_iotiming_get,
+
+	.resume_clocks	= s3c2412_setup_clocks,
+
+	.debug_io_show  = s3c_cpufreq_debugfs_call(s3c2412_iotiming_debugfs),
+};
+
+static int s3c2412_cpufreq_add(struct device *dev,
+			       struct subsys_interface *sif)
+{
+	unsigned long fclk_rate;
+
+	hclk = clk_get(NULL, "hclk");
+	if (IS_ERR(hclk)) {
+		printk(KERN_ERR "%s: cannot find hclk clock\n", __func__);
+		return -ENOENT;
+	}
+
+	fclk = clk_get(NULL, "fclk");
+	if (IS_ERR(fclk)) {
+		printk(KERN_ERR "%s: cannot find fclk clock\n", __func__);
+		goto err_fclk;
+	}
+
+	fclk_rate = clk_get_rate(fclk);
+	if (fclk_rate > 200000000) {
+		printk(KERN_INFO
+		       "%s: fclk %ld MHz, assuming 266MHz capable part\n",
+		       __func__, fclk_rate / 1000000);
+		s3c2412_cpufreq_info.max.fclk = 266000000;
+		s3c2412_cpufreq_info.max.hclk = 133000000;
+		s3c2412_cpufreq_info.max.pclk =  66000000;
+	}
+
+	armclk = clk_get(NULL, "armclk");
+	if (IS_ERR(armclk)) {
+		printk(KERN_ERR "%s: cannot find arm clock\n", __func__);
+		goto err_armclk;
+	}
+
+	xtal = clk_get(NULL, "xtal");
+	if (IS_ERR(xtal)) {
+		printk(KERN_ERR "%s: cannot find xtal clock\n", __func__);
+		goto err_xtal;
+	}
+
+	return s3c_cpufreq_register(&s3c2412_cpufreq_info);
+
+err_xtal:
+	clk_put(armclk);
+err_armclk:
+	clk_put(fclk);
+err_fclk:
+	clk_put(hclk);
+
+	return -ENOENT;
+}
+
+static struct subsys_interface s3c2412_cpufreq_interface = {
+	.name		= "s3c2412_cpufreq",
+	.subsys		= &s3c2412_subsys,
+	.add_dev	= s3c2412_cpufreq_add,
+};
+
+static int s3c2412_cpufreq_init(void)
+{
+	return subsys_interface_register(&s3c2412_cpufreq_interface);
+}
+arch_initcall(s3c2412_cpufreq_init);
diff --git a/drivers/cpufreq/s3c2440-cpufreq.c b/drivers/cpufreq/s3c2440-cpufreq.c
new file mode 100644
index 000000000000..72b2cc8a5a85
--- /dev/null
+++ b/drivers/cpufreq/s3c2440-cpufreq.c
@@ -0,0 +1,312 @@
+/*
+ * Copyright (c) 2006-2009 Simtec Electronics
+ *	http://armlinux.simtec.co.uk/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *	Vincent Sanders <vince@simtec.co.uk>
+ *
+ * S3C2440/S3C2442 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/delay.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+
+#include <mach/hardware.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>
+#include <plat/clock.h>
+
+static struct clk *xtal;
+static struct clk *fclk;
+static struct clk *hclk;
+static struct clk *armclk;
+
+/* HDIV: 1, 2, 3, 4, 6, 8 */
+
+static inline int within_khz(unsigned long a, unsigned long b)
+{
+	long diff = a - b;
+
+	return (diff >= -1000 && diff <= 1000);
+}
+
+/**
+ * s3c2440_cpufreq_calcdivs - calculate divider settings
+ * @cfg: The cpu frequency settings.
+ *
+ * Calcualte the divider values for the given frequency settings
+ * specified in @cfg. The values are stored in @cfg for later use
+ * by the relevant set routine if the request settings can be reached.
+ */
+int s3c2440_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
+{
+	unsigned int hdiv, pdiv;
+	unsigned long hclk, fclk, armclk;
+	unsigned long hclk_max;
+
+	fclk = cfg->freq.fclk;
+	armclk = cfg->freq.armclk;
+	hclk_max = cfg->max.hclk;
+
+	s3c_freq_dbg("%s: fclk is %lu, armclk %lu, max hclk %lu\n",
+		     __func__, fclk, armclk, hclk_max);
+
+	if (armclk > fclk) {
+		printk(KERN_WARNING "%s: armclk > fclk\n", __func__);
+		armclk = fclk;
+	}
+
+	/* if we are in DVS, we need HCLK to be <= ARMCLK */
+	if (armclk < fclk && armclk < hclk_max)
+		hclk_max = armclk;
+
+	for (hdiv = 1; hdiv < 9; hdiv++) {
+		if (hdiv == 5 || hdiv == 7)
+			hdiv++;
+
+		hclk = (fclk / hdiv);
+		if (hclk <= hclk_max || within_khz(hclk, hclk_max))
+			break;
+	}
+
+	s3c_freq_dbg("%s: hclk %lu, div %d\n", __func__, hclk, hdiv);
+
+	if (hdiv > 8)
+		goto invalid;
+
+	pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
+
+	if ((hclk / pdiv) > cfg->max.pclk)
+		pdiv++;
+
+	s3c_freq_dbg("%s: pdiv %d\n", __func__, pdiv);
+
+	if (pdiv > 2)
+		goto invalid;
+
+	pdiv *= hdiv;
+
+	/* calculate a valid armclk */
+
+	if (armclk < hclk)
+		armclk = hclk;
+
+	/* if we're running armclk lower than fclk, this really means
+	 * that the system should go into dvs mode, which means that
+	 * armclk is connected to hclk. */
+	if (armclk < fclk) {
+		cfg->divs.dvs = 1;
+		armclk = hclk;
+	} else
+		cfg->divs.dvs = 0;
+
+	cfg->freq.armclk = armclk;
+
+	/* store the result, and then return */
+
+	cfg->divs.h_divisor = hdiv;
+	cfg->divs.p_divisor = pdiv;
+
+	return 0;
+
+ invalid:
+	return -EINVAL;
+}
+
+#define CAMDIVN_HCLK_HALF (S3C2440_CAMDIVN_HCLK3_HALF | \
+			   S3C2440_CAMDIVN_HCLK4_HALF)
+
+/**
+ * s3c2440_cpufreq_setdivs - set the cpu frequency divider settings
+ * @cfg: The cpu frequency settings.
+ *
+ * Set the divisors from the settings in @cfg, which where generated
+ * during the calculation phase by s3c2440_cpufreq_calcdivs().
+ */
+static void s3c2440_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
+{
+	unsigned long clkdiv, camdiv;
+
+	s3c_freq_dbg("%s: divsiors: h=%d, p=%d\n", __func__,
+		     cfg->divs.h_divisor, cfg->divs.p_divisor);
+
+	clkdiv = __raw_readl(S3C2410_CLKDIVN);
+	camdiv = __raw_readl(S3C2440_CAMDIVN);
+
+	clkdiv &= ~(S3C2440_CLKDIVN_HDIVN_MASK | S3C2440_CLKDIVN_PDIVN);
+	camdiv &= ~CAMDIVN_HCLK_HALF;
+
+	switch (cfg->divs.h_divisor) {
+	case 1:
+		clkdiv |= S3C2440_CLKDIVN_HDIVN_1;
+		break;
+
+	case 2:
+		clkdiv |= S3C2440_CLKDIVN_HDIVN_2;
+		break;
+
+	case 6:
+		camdiv |= S3C2440_CAMDIVN_HCLK3_HALF;
+	case 3:
+		clkdiv |= S3C2440_CLKDIVN_HDIVN_3_6;
+		break;
+
+	case 8:
+		camdiv |= S3C2440_CAMDIVN_HCLK4_HALF;
+	case 4:
+		clkdiv |= S3C2440_CLKDIVN_HDIVN_4_8;
+		break;
+
+	default:
+		BUG();	/* we don't expect to get here. */
+	}
+
+	if (cfg->divs.p_divisor != cfg->divs.h_divisor)
+		clkdiv |= S3C2440_CLKDIVN_PDIVN;
+
+	/* todo - set pclk. */
+
+	/* Write the divisors first with hclk intentionally halved so that
+	 * when we write clkdiv we will under-frequency instead of over. We
+	 * then make a short delay and remove the hclk halving if necessary.
+	 */
+
+	__raw_writel(camdiv | CAMDIVN_HCLK_HALF, S3C2440_CAMDIVN);
+	__raw_writel(clkdiv, S3C2410_CLKDIVN);
+
+	ndelay(20);
+	__raw_writel(camdiv, S3C2440_CAMDIVN);
+
+	clk_set_parent(armclk, cfg->divs.dvs ? hclk : fclk);
+}
+
+static int run_freq_for(unsigned long max_hclk, unsigned long fclk,
+			int *divs,
+			struct cpufreq_frequency_table *table,
+			size_t table_size)
+{
+	unsigned long freq;
+	int index = 0;
+	int div;
+
+	for (div = *divs; div > 0; div = *divs++) {
+		freq = fclk / div;
+
+		if (freq > max_hclk && div != 1)
+			continue;
+
+		freq /= 1000; /* table is in kHz */
+		index = s3c_cpufreq_addfreq(table, index, table_size, freq);
+		if (index < 0)
+			break;
+	}
+
+	return index;
+}
+
+static int hclk_divs[] = { 1, 2, 3, 4, 6, 8, -1 };
+
+static int s3c2440_cpufreq_calctable(struct s3c_cpufreq_config *cfg,
+				     struct cpufreq_frequency_table *table,
+				     size_t table_size)
+{
+	int ret;
+
+	WARN_ON(cfg->info == NULL);
+	WARN_ON(cfg->board == NULL);
+
+	ret = run_freq_for(cfg->info->max.hclk,
+			   cfg->info->max.fclk,
+			   hclk_divs,
+			   table, table_size);
+
+	s3c_freq_dbg("%s: returning %d\n", __func__, ret);
+
+	return ret;
+}
+
+struct s3c_cpufreq_info s3c2440_cpufreq_info = {
+	.max		= {
+		.fclk	= 400000000,
+		.hclk	= 133333333,
+		.pclk	=  66666666,
+	},
+
+	.locktime_m	= 300,
+	.locktime_u	= 300,
+	.locktime_bits	= 16,
+
+	.name		= "s3c244x",
+	.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	= s3c2440_cpufreq_setdivs,
+	.calc_divs	= s3c2440_cpufreq_calcdivs,
+	.calc_freqtable	= s3c2440_cpufreq_calctable,
+
+	.resume_clocks	= s3c244x_setup_clocks,
+
+	.debug_io_show  = s3c_cpufreq_debugfs_call(s3c2410_iotiming_debugfs),
+};
+
+static int s3c2440_cpufreq_add(struct device *dev,
+			       struct subsys_interface *sif)
+{
+	xtal = s3c_cpufreq_clk_get(NULL, "xtal");
+	hclk = s3c_cpufreq_clk_get(NULL, "hclk");
+	fclk = s3c_cpufreq_clk_get(NULL, "fclk");
+	armclk = s3c_cpufreq_clk_get(NULL, "armclk");
+
+	if (IS_ERR(xtal) || IS_ERR(hclk) || IS_ERR(fclk) || IS_ERR(armclk)) {
+		printk(KERN_ERR "%s: failed to get clocks\n", __func__);
+		return -ENOENT;
+	}
+
+	return s3c_cpufreq_register(&s3c2440_cpufreq_info);
+}
+
+static struct subsys_interface s3c2440_cpufreq_interface = {
+	.name		= "s3c2440_cpufreq",
+	.subsys		= &s3c2440_subsys,
+	.add_dev	= s3c2440_cpufreq_add,
+};
+
+static int s3c2440_cpufreq_init(void)
+{
+	return subsys_interface_register(&s3c2440_cpufreq_interface);
+}
+
+/* arch_initcall adds the clocks we need, so use subsys_initcall. */
+subsys_initcall(s3c2440_cpufreq_init);
+
+static struct subsys_interface s3c2442_cpufreq_interface = {
+	.name		= "s3c2442_cpufreq",
+	.subsys		= &s3c2442_subsys,
+	.add_dev	= s3c2440_cpufreq_add,
+};
+
+static int s3c2442_cpufreq_init(void)
+{
+	return subsys_interface_register(&s3c2442_cpufreq_interface);
+}
+subsys_initcall(s3c2442_cpufreq_init);
diff --git a/drivers/cpufreq/s3c24xx-cpufreq-debugfs.c b/drivers/cpufreq/s3c24xx-cpufreq-debugfs.c
new file mode 100644
index 000000000000..9b7b4289d66c
--- /dev/null
+++ b/drivers/cpufreq/s3c24xx-cpufreq-debugfs.c
@@ -0,0 +1,198 @@
+/*
+ * Copyright (c) 2009 Simtec Electronics
+ *	http://armlinux.simtec.co.uk/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C24XX CPU Frequency scaling - debugfs status support
+ *
+ * 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/export.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/cpufreq.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
+
+#include <plat/cpu-freq-core.h>
+
+static struct dentry *dbgfs_root;
+static struct dentry *dbgfs_file_io;
+static struct dentry *dbgfs_file_info;
+static struct dentry *dbgfs_file_board;
+
+#define print_ns(x) ((x) / 10), ((x) % 10)
+
+static void show_max(struct seq_file *seq, struct s3c_freq *f)
+{
+	seq_printf(seq, "MAX: F=%lu, H=%lu, P=%lu, A=%lu\n",
+		   f->fclk, f->hclk, f->pclk, f->armclk);
+}
+
+static int board_show(struct seq_file *seq, void *p)
+{
+	struct s3c_cpufreq_config *cfg;
+	struct s3c_cpufreq_board *brd;
+
+	cfg = s3c_cpufreq_getconfig();
+	if (!cfg) {
+		seq_printf(seq, "no configuration registered\n");
+		return 0;
+	}
+
+	brd = cfg->board;
+	if (!brd) {
+		seq_printf(seq, "no board definition set?\n");
+		return 0;
+	}
+
+	seq_printf(seq, "SDRAM refresh %u ns\n", brd->refresh);
+	seq_printf(seq, "auto_io=%u\n", brd->auto_io);
+	seq_printf(seq, "need_io=%u\n", brd->need_io);
+
+	show_max(seq, &brd->max);
+
+
+	return 0;
+}
+
+static int fops_board_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, board_show, NULL);
+}
+
+static const struct file_operations fops_board = {
+	.open		= fops_board_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+	.owner		= THIS_MODULE,
+};
+
+static int info_show(struct seq_file *seq, void *p)
+{
+	struct s3c_cpufreq_config *cfg;
+
+	cfg = s3c_cpufreq_getconfig();
+	if (!cfg) {
+		seq_printf(seq, "no configuration registered\n");
+		return 0;
+	}
+
+	seq_printf(seq, "  FCLK %ld Hz\n", cfg->freq.fclk);
+	seq_printf(seq, "  HCLK %ld Hz (%lu.%lu ns)\n",
+		   cfg->freq.hclk, print_ns(cfg->freq.hclk_tns));
+	seq_printf(seq, "  PCLK %ld Hz\n", cfg->freq.hclk);
+	seq_printf(seq, "ARMCLK %ld Hz\n", cfg->freq.armclk);
+	seq_printf(seq, "\n");
+
+	show_max(seq, &cfg->max);
+
+	seq_printf(seq, "Divisors: P=%d, H=%d, A=%d, dvs=%s\n",
+		   cfg->divs.h_divisor, cfg->divs.p_divisor,
+		   cfg->divs.arm_divisor, cfg->divs.dvs ? "on" : "off");
+	seq_printf(seq, "\n");
+
+	seq_printf(seq, "lock_pll=%u\n", cfg->lock_pll);
+
+	return 0;
+}
+
+static int fops_info_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, info_show, NULL);
+}
+
+static const struct file_operations fops_info = {
+	.open		= fops_info_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+	.owner		= THIS_MODULE,
+};
+
+static int io_show(struct seq_file *seq, void *p)
+{
+	void (*show_bank)(struct seq_file *, struct s3c_cpufreq_config *, union s3c_iobank *);
+	struct s3c_cpufreq_config *cfg;
+	struct s3c_iotimings *iot;
+	union s3c_iobank *iob;
+	int bank;
+
+	cfg = s3c_cpufreq_getconfig();
+	if (!cfg) {
+		seq_printf(seq, "no configuration registered\n");
+		return 0;
+	}
+
+	show_bank = cfg->info->debug_io_show;
+	if (!show_bank) {
+		seq_printf(seq, "no code to show bank timing\n");
+		return 0;
+	}
+
+	iot = s3c_cpufreq_getiotimings();
+	if (!iot) {
+		seq_printf(seq, "no io timings registered\n");
+		return 0;
+	}
+
+	seq_printf(seq, "hclk period is %lu.%lu ns\n", print_ns(cfg->freq.hclk_tns));
+
+	for (bank = 0; bank < MAX_BANKS; bank++) {
+		iob = &iot->bank[bank];
+
+		seq_printf(seq, "bank %d: ", bank);
+
+		if (!iob->io_2410) {
+			seq_printf(seq, "nothing set\n");
+			continue;
+		}
+
+		show_bank(seq, cfg, iob);
+	}
+
+	return 0;
+}
+
+static int fops_io_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, io_show, NULL);
+}
+
+static const struct file_operations fops_io = {
+	.open		= fops_io_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+	.owner		= THIS_MODULE,
+};
+
+
+static int __init s3c_freq_debugfs_init(void)
+{
+	dbgfs_root = debugfs_create_dir("s3c-cpufreq", NULL);
+	if (IS_ERR(dbgfs_root)) {
+		printk(KERN_ERR "%s: error creating debugfs root\n", __func__);
+		return PTR_ERR(dbgfs_root);
+	}
+
+	dbgfs_file_io = debugfs_create_file("io-timing", S_IRUGO, dbgfs_root,
+					    NULL, &fops_io);
+
+	dbgfs_file_info = debugfs_create_file("info", S_IRUGO, dbgfs_root,
+					      NULL, &fops_info);
+
+	dbgfs_file_board = debugfs_create_file("board", S_IRUGO, dbgfs_root,
+					       NULL, &fops_board);
+
+	return 0;
+}
+
+late_initcall(s3c_freq_debugfs_init);
+
diff --git a/drivers/cpufreq/s3c24xx-cpufreq.c b/drivers/cpufreq/s3c24xx-cpufreq.c
new file mode 100644
index 000000000000..3c0e78ede0da
--- /dev/null
+++ b/drivers/cpufreq/s3c24xx-cpufreq.c
@@ -0,0 +1,711 @@
+/*
+ * Copyright (c) 2006-2008 Simtec Electronics
+ *	http://armlinux.simtec.co.uk/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C24XX 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/cpu.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/device.h>
+#include <linux/sysfs.h>
+#include <linux/slab.h>
+
+#include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+
+#include <plat/cpu.h>
+#include <plat/clock.h>
+#include <plat/cpu-freq-core.h>
+
+#include <mach/regs-clock.h>
+
+/* note, cpufreq support deals in kHz, no Hz */
+
+static struct cpufreq_driver s3c24xx_driver;
+static struct s3c_cpufreq_config cpu_cur;
+static struct s3c_iotimings s3c24xx_iotiming;
+static struct cpufreq_frequency_table *pll_reg;
+static unsigned int last_target = ~0;
+static unsigned int ftab_size;
+static struct cpufreq_frequency_table *ftab;
+
+static struct clk *_clk_mpll;
+static struct clk *_clk_xtal;
+static struct clk *clk_fclk;
+static struct clk *clk_hclk;
+static struct clk *clk_pclk;
+static struct clk *clk_arm;
+
+#ifdef CONFIG_CPU_FREQ_S3C24XX_DEBUGFS
+struct s3c_cpufreq_config *s3c_cpufreq_getconfig(void)
+{
+	return &cpu_cur;
+}
+
+struct s3c_iotimings *s3c_cpufreq_getiotimings(void)
+{
+	return &s3c24xx_iotiming;
+}
+#endif /* CONFIG_CPU_FREQ_S3C24XX_DEBUGFS */
+
+static void s3c_cpufreq_getcur(struct s3c_cpufreq_config *cfg)
+{
+	unsigned long fclk, pclk, hclk, armclk;
+
+	cfg->freq.fclk = fclk = clk_get_rate(clk_fclk);
+	cfg->freq.hclk = hclk = clk_get_rate(clk_hclk);
+	cfg->freq.pclk = pclk = clk_get_rate(clk_pclk);
+	cfg->freq.armclk = armclk = clk_get_rate(clk_arm);
+
+	cfg->pll.index = __raw_readl(S3C2410_MPLLCON);
+	cfg->pll.frequency = fclk;
+
+	cfg->freq.hclk_tns = 1000000000 / (cfg->freq.hclk / 10);
+
+	cfg->divs.h_divisor = fclk / hclk;
+	cfg->divs.p_divisor = fclk / pclk;
+}
+
+static inline void s3c_cpufreq_calc(struct s3c_cpufreq_config *cfg)
+{
+	unsigned long pll = cfg->pll.frequency;
+
+	cfg->freq.fclk = pll;
+	cfg->freq.hclk = pll / cfg->divs.h_divisor;
+	cfg->freq.pclk = pll / cfg->divs.p_divisor;
+
+	/* convert hclk into 10ths of nanoseconds for io calcs */
+	cfg->freq.hclk_tns = 1000000000 / (cfg->freq.hclk / 10);
+}
+
+static inline int closer(unsigned int target, unsigned int n, unsigned int c)
+{
+	int diff_cur = abs(target - c);
+	int diff_new = abs(target - n);
+
+	return (diff_new < diff_cur);
+}
+
+static void s3c_cpufreq_show(const char *pfx,
+				 struct s3c_cpufreq_config *cfg)
+{
+	s3c_freq_dbg("%s: Fvco=%u, F=%lu, A=%lu, H=%lu (%u), P=%lu (%u)\n",
+		     pfx, cfg->pll.frequency, cfg->freq.fclk, cfg->freq.armclk,
+		     cfg->freq.hclk, cfg->divs.h_divisor,
+		     cfg->freq.pclk, cfg->divs.p_divisor);
+}
+
+/* functions to wrapper the driver info calls to do the cpu specific work */
+
+static void s3c_cpufreq_setio(struct s3c_cpufreq_config *cfg)
+{
+	if (cfg->info->set_iotiming)
+		(cfg->info->set_iotiming)(cfg, &s3c24xx_iotiming);
+}
+
+static int s3c_cpufreq_calcio(struct s3c_cpufreq_config *cfg)
+{
+	if (cfg->info->calc_iotiming)
+		return (cfg->info->calc_iotiming)(cfg, &s3c24xx_iotiming);
+
+	return 0;
+}
+
+static void s3c_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
+{
+	(cfg->info->set_refresh)(cfg);
+}
+
+static void s3c_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
+{
+	(cfg->info->set_divs)(cfg);
+}
+
+static int s3c_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
+{
+	return (cfg->info->calc_divs)(cfg);
+}
+
+static void s3c_cpufreq_setfvco(struct s3c_cpufreq_config *cfg)
+{
+	(cfg->info->set_fvco)(cfg);
+}
+
+static inline void s3c_cpufreq_resume_clocks(void)
+{
+	cpu_cur.info->resume_clocks();
+}
+
+static inline void s3c_cpufreq_updateclk(struct clk *clk,
+					 unsigned int freq)
+{
+	clk_set_rate(clk, freq);
+}
+
+static int s3c_cpufreq_settarget(struct cpufreq_policy *policy,
+				 unsigned int target_freq,
+				 struct cpufreq_frequency_table *pll)
+{
+	struct s3c_cpufreq_freqs freqs;
+	struct s3c_cpufreq_config cpu_new;
+	unsigned long flags;
+
+	cpu_new = cpu_cur;  /* copy new from current */
+
+	s3c_cpufreq_show("cur", &cpu_cur);
+
+	/* TODO - check for DMA currently outstanding */
+
+	cpu_new.pll = pll ? *pll : cpu_cur.pll;
+
+	if (pll)
+		freqs.pll_changing = 1;
+
+	/* update our frequencies */
+
+	cpu_new.freq.armclk = target_freq;
+	cpu_new.freq.fclk = cpu_new.pll.frequency;
+
+	if (s3c_cpufreq_calcdivs(&cpu_new) < 0) {
+		printk(KERN_ERR "no divisors for %d\n", target_freq);
+		goto err_notpossible;
+	}
+
+	s3c_freq_dbg("%s: got divs\n", __func__);
+
+	s3c_cpufreq_calc(&cpu_new);
+
+	s3c_freq_dbg("%s: calculated frequencies for new\n", __func__);
+
+	if (cpu_new.freq.hclk != cpu_cur.freq.hclk) {
+		if (s3c_cpufreq_calcio(&cpu_new) < 0) {
+			printk(KERN_ERR "%s: no IO timings\n", __func__);
+			goto err_notpossible;
+		}
+	}
+
+	s3c_cpufreq_show("new", &cpu_new);
+
+	/* setup our cpufreq parameters */
+
+	freqs.old = cpu_cur.freq;
+	freqs.new = cpu_new.freq;
+
+	freqs.freqs.old = cpu_cur.freq.armclk / 1000;
+	freqs.freqs.new = cpu_new.freq.armclk / 1000;
+
+	/* update f/h/p clock settings before we issue the change
+	 * notification, so that drivers do not need to do anything
+	 * special if they want to recalculate on CPUFREQ_PRECHANGE. */
+
+	s3c_cpufreq_updateclk(_clk_mpll, cpu_new.pll.frequency);
+	s3c_cpufreq_updateclk(clk_fclk, cpu_new.freq.fclk);
+	s3c_cpufreq_updateclk(clk_hclk, cpu_new.freq.hclk);
+	s3c_cpufreq_updateclk(clk_pclk, cpu_new.freq.pclk);
+
+	/* start the frequency change */
+	cpufreq_notify_transition(policy, &freqs.freqs, CPUFREQ_PRECHANGE);
+
+	/* If hclk is staying the same, then we do not need to
+	 * re-write the IO or the refresh timings whilst we are changing
+	 * speed. */
+
+	local_irq_save(flags);
+
+	/* is our memory clock slowing down? */
+	if (cpu_new.freq.hclk < cpu_cur.freq.hclk) {
+		s3c_cpufreq_setrefresh(&cpu_new);
+		s3c_cpufreq_setio(&cpu_new);
+	}
+
+	if (cpu_new.freq.fclk == cpu_cur.freq.fclk) {
+		/* not changing PLL, just set the divisors */
+
+		s3c_cpufreq_setdivs(&cpu_new);
+	} else {
+		if (cpu_new.freq.fclk < cpu_cur.freq.fclk) {
+			/* slow the cpu down, then set divisors */
+
+			s3c_cpufreq_setfvco(&cpu_new);
+			s3c_cpufreq_setdivs(&cpu_new);
+		} else {
+			/* set the divisors, then speed up */
+
+			s3c_cpufreq_setdivs(&cpu_new);
+			s3c_cpufreq_setfvco(&cpu_new);
+		}
+	}
+
+	/* did our memory clock speed up */
+	if (cpu_new.freq.hclk > cpu_cur.freq.hclk) {
+		s3c_cpufreq_setrefresh(&cpu_new);
+		s3c_cpufreq_setio(&cpu_new);
+	}
+
+	/* update our current settings */
+	cpu_cur = cpu_new;
+
+	local_irq_restore(flags);
+
+	/* notify everyone we've done this */
+	cpufreq_notify_transition(policy, &freqs.freqs, CPUFREQ_POSTCHANGE);
+
+	s3c_freq_dbg("%s: finished\n", __func__);
+	return 0;
+
+ err_notpossible:
+	printk(KERN_ERR "no compatible settings for %d\n", target_freq);
+	return -EINVAL;
+}
+
+/* s3c_cpufreq_target
+ *
+ * called by the cpufreq core to adjust the frequency that the CPU
+ * is currently running at.
+ */
+
+static int s3c_cpufreq_target(struct cpufreq_policy *policy,
+			      unsigned int target_freq,
+			      unsigned int relation)
+{
+	struct cpufreq_frequency_table *pll;
+	unsigned int index;
+
+	/* avoid repeated calls which cause a needless amout of duplicated
+	 * logging output (and CPU time as the calculation process is
+	 * done) */
+	if (target_freq == last_target)
+		return 0;
+
+	last_target = target_freq;
+
+	s3c_freq_dbg("%s: policy %p, target %u, relation %u\n",
+		     __func__, policy, target_freq, relation);
+
+	if (ftab) {
+		if (cpufreq_frequency_table_target(policy, ftab,
+						   target_freq, relation,
+						   &index)) {
+			s3c_freq_dbg("%s: table failed\n", __func__);
+			return -EINVAL;
+		}
+
+		s3c_freq_dbg("%s: adjust %d to entry %d (%u)\n", __func__,
+			     target_freq, index, ftab[index].frequency);
+		target_freq = ftab[index].frequency;
+	}
+
+	target_freq *= 1000;  /* convert target to Hz */
+
+	/* find the settings for our new frequency */
+
+	if (!pll_reg || cpu_cur.lock_pll) {
+		/* either we've not got any PLL values, or we've locked
+		 * to the current one. */
+		pll = NULL;
+	} else {
+		struct cpufreq_policy tmp_policy;
+		int ret;
+
+		/* we keep the cpu pll table in Hz, to ensure we get an
+		 * accurate value for the PLL output. */
+
+		tmp_policy.min = policy->min * 1000;
+		tmp_policy.max = policy->max * 1000;
+		tmp_policy.cpu = policy->cpu;
+
+		/* cpufreq_frequency_table_target uses a pointer to 'index'
+		 * which is the number of the table entry, not the value of
+		 * the table entry's index field. */
+
+		ret = cpufreq_frequency_table_target(&tmp_policy, pll_reg,
+						     target_freq, relation,
+						     &index);
+
+		if (ret < 0) {
+			printk(KERN_ERR "%s: no PLL available\n", __func__);
+			goto err_notpossible;
+		}
+
+		pll = pll_reg + index;
+
+		s3c_freq_dbg("%s: target %u => %u\n",
+			     __func__, target_freq, pll->frequency);
+
+		target_freq = pll->frequency;
+	}
+
+	return s3c_cpufreq_settarget(policy, target_freq, pll);
+
+ err_notpossible:
+	printk(KERN_ERR "no compatible settings for %d\n", target_freq);
+	return -EINVAL;
+}
+
+static unsigned int s3c_cpufreq_get(unsigned int cpu)
+{
+	return clk_get_rate(clk_arm) / 1000;
+}
+
+struct clk *s3c_cpufreq_clk_get(struct device *dev, const char *name)
+{
+	struct clk *clk;
+
+	clk = clk_get(dev, name);
+	if (IS_ERR(clk))
+		printk(KERN_ERR "cpufreq: failed to get clock '%s'\n", name);
+
+	return clk;
+}
+
+static int s3c_cpufreq_init(struct cpufreq_policy *policy)
+{
+	printk(KERN_INFO "%s: initialising policy %p\n", __func__, policy);
+
+	if (policy->cpu != 0)
+		return -EINVAL;
+
+	policy->cur = s3c_cpufreq_get(0);
+	policy->min = policy->cpuinfo.min_freq = 0;
+	policy->max = policy->cpuinfo.max_freq = cpu_cur.info->max.fclk / 1000;
+	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
+
+	/* feed the latency information from the cpu driver */
+	policy->cpuinfo.transition_latency = cpu_cur.info->latency;
+
+	if (ftab)
+		cpufreq_frequency_table_cpuinfo(policy, ftab);
+
+	return 0;
+}
+
+static __init int s3c_cpufreq_initclks(void)
+{
+	_clk_mpll = s3c_cpufreq_clk_get(NULL, "mpll");
+	_clk_xtal = s3c_cpufreq_clk_get(NULL, "xtal");
+	clk_fclk = s3c_cpufreq_clk_get(NULL, "fclk");
+	clk_hclk = s3c_cpufreq_clk_get(NULL, "hclk");
+	clk_pclk = s3c_cpufreq_clk_get(NULL, "pclk");
+	clk_arm = s3c_cpufreq_clk_get(NULL, "armclk");
+
+	if (IS_ERR(clk_fclk) || IS_ERR(clk_hclk) || IS_ERR(clk_pclk) ||
+	    IS_ERR(_clk_mpll) || IS_ERR(clk_arm) || IS_ERR(_clk_xtal)) {
+		printk(KERN_ERR "%s: could not get clock(s)\n", __func__);
+		return -ENOENT;
+	}
+
+	printk(KERN_INFO "%s: clocks f=%lu,h=%lu,p=%lu,a=%lu\n", __func__,
+	       clk_get_rate(clk_fclk) / 1000,
+	       clk_get_rate(clk_hclk) / 1000,
+	       clk_get_rate(clk_pclk) / 1000,
+	       clk_get_rate(clk_arm) / 1000);
+
+	return 0;
+}
+
+static int s3c_cpufreq_verify(struct cpufreq_policy *policy)
+{
+	if (policy->cpu != 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static struct cpufreq_frequency_table suspend_pll;
+static unsigned int suspend_freq;
+
+static int s3c_cpufreq_suspend(struct cpufreq_policy *policy)
+{
+	suspend_pll.frequency = clk_get_rate(_clk_mpll);
+	suspend_pll.index = __raw_readl(S3C2410_MPLLCON);
+	suspend_freq = s3c_cpufreq_get(0) * 1000;
+
+	return 0;
+}
+
+static int s3c_cpufreq_resume(struct cpufreq_policy *policy)
+{
+	int ret;
+
+	s3c_freq_dbg("%s: resuming with policy %p\n", __func__, policy);
+
+	last_target = ~0;	/* invalidate last_target setting */
+
+	/* first, find out what speed we resumed at. */
+	s3c_cpufreq_resume_clocks();
+
+	/* whilst we will be called later on, we try and re-set the
+	 * cpu frequencies as soon as possible so that we do not end
+	 * up resuming devices and then immediately having to re-set
+	 * a number of settings once these devices have restarted.
+	 *
+	 * as a note, it is expected devices are not used until they
+	 * have been un-suspended and at that time they should have
+	 * used the updated clock settings.
+	 */
+
+	ret = s3c_cpufreq_settarget(NULL, suspend_freq, &suspend_pll);
+	if (ret) {
+		printk(KERN_ERR "%s: failed to reset pll/freq\n", __func__);
+		return ret;
+	}
+
+	return 0;
+}
+#else
+#define s3c_cpufreq_resume NULL
+#define s3c_cpufreq_suspend NULL
+#endif
+
+static struct cpufreq_driver s3c24xx_driver = {
+	.flags		= CPUFREQ_STICKY,
+	.verify		= s3c_cpufreq_verify,
+	.target		= s3c_cpufreq_target,
+	.get		= s3c_cpufreq_get,
+	.init		= s3c_cpufreq_init,
+	.suspend	= s3c_cpufreq_suspend,
+	.resume		= s3c_cpufreq_resume,
+	.name		= "s3c24xx",
+};
+
+
+int __init s3c_cpufreq_register(struct s3c_cpufreq_info *info)
+{
+	if (!info || !info->name) {
+		printk(KERN_ERR "%s: failed to pass valid information\n",
+		       __func__);
+		return -EINVAL;
+	}
+
+	printk(KERN_INFO "S3C24XX CPU Frequency driver, %s cpu support\n",
+	       info->name);
+
+	/* check our driver info has valid data */
+
+	BUG_ON(info->set_refresh == NULL);
+	BUG_ON(info->set_divs == NULL);
+	BUG_ON(info->calc_divs == NULL);
+
+	/* info->set_fvco is optional, depending on whether there
+	 * is a need to set the clock code. */
+
+	cpu_cur.info = info;
+
+	/* Note, driver registering should probably update locktime */
+
+	return 0;
+}
+
+int __init s3c_cpufreq_setboard(struct s3c_cpufreq_board *board)
+{
+	struct s3c_cpufreq_board *ours;
+
+	if (!board) {
+		printk(KERN_INFO "%s: no board data\n", __func__);
+		return -EINVAL;
+	}
+
+	/* Copy the board information so that each board can make this
+	 * initdata. */
+
+	ours = kzalloc(sizeof(struct s3c_cpufreq_board), GFP_KERNEL);
+	if (ours == NULL) {
+		printk(KERN_ERR "%s: no memory\n", __func__);
+		return -ENOMEM;
+	}
+
+	*ours = *board;
+	cpu_cur.board = ours;
+
+	return 0;
+}
+
+int __init s3c_cpufreq_auto_io(void)
+{
+	int ret;
+
+	if (!cpu_cur.info->get_iotiming) {
+		printk(KERN_ERR "%s: get_iotiming undefined\n", __func__);
+		return -ENOENT;
+	}
+
+	printk(KERN_INFO "%s: working out IO settings\n", __func__);
+
+	ret = (cpu_cur.info->get_iotiming)(&cpu_cur, &s3c24xx_iotiming);
+	if (ret)
+		printk(KERN_ERR "%s: failed to get timings\n", __func__);
+
+	return ret;
+}
+
+/* if one or is zero, then return the other, otherwise return the min */
+#define do_min(_a, _b) ((_a) == 0 ? (_b) : (_b) == 0 ? (_a) : min(_a, _b))
+
+/**
+ * s3c_cpufreq_freq_min - find the minimum settings for the given freq.
+ * @dst: The destination structure
+ * @a: One argument.
+ * @b: The other argument.
+ *
+ * Create a minimum of each frequency entry in the 'struct s3c_freq',
+ * unless the entry is zero when it is ignored and the non-zero argument
+ * used.
+ */
+static void s3c_cpufreq_freq_min(struct s3c_freq *dst,
+				 struct s3c_freq *a, struct s3c_freq *b)
+{
+	dst->fclk = do_min(a->fclk, b->fclk);
+	dst->hclk = do_min(a->hclk, b->hclk);
+	dst->pclk = do_min(a->pclk, b->pclk);
+	dst->armclk = do_min(a->armclk, b->armclk);
+}
+
+static inline u32 calc_locktime(u32 freq, u32 time_us)
+{
+	u32 result;
+
+	result = freq * time_us;
+	result = DIV_ROUND_UP(result, 1000 * 1000);
+
+	return result;
+}
+
+static void s3c_cpufreq_update_loctkime(void)
+{
+	unsigned int bits = cpu_cur.info->locktime_bits;
+	u32 rate = (u32)clk_get_rate(_clk_xtal);
+	u32 val;
+
+	if (bits == 0) {
+		WARN_ON(1);
+		return;
+	}
+
+	val = calc_locktime(rate, cpu_cur.info->locktime_u) << bits;
+	val |= calc_locktime(rate, cpu_cur.info->locktime_m);
+
+	printk(KERN_INFO "%s: new locktime is 0x%08x\n", __func__, val);
+	__raw_writel(val, S3C2410_LOCKTIME);
+}
+
+static int s3c_cpufreq_build_freq(void)
+{
+	int size, ret;
+
+	if (!cpu_cur.info->calc_freqtable)
+		return -EINVAL;
+
+	kfree(ftab);
+	ftab = NULL;
+
+	size = cpu_cur.info->calc_freqtable(&cpu_cur, NULL, 0);
+	size++;
+
+	ftab = kmalloc(sizeof(struct cpufreq_frequency_table) * size, GFP_KERNEL);
+	if (!ftab) {
+		printk(KERN_ERR "%s: no memory for tables\n", __func__);
+		return -ENOMEM;
+	}
+
+	ftab_size = size;
+
+	ret = cpu_cur.info->calc_freqtable(&cpu_cur, ftab, size);
+	s3c_cpufreq_addfreq(ftab, ret, size, CPUFREQ_TABLE_END);
+
+	return 0;
+}
+
+static int __init s3c_cpufreq_initcall(void)
+{
+	int ret = 0;
+
+	if (cpu_cur.info && cpu_cur.board) {
+		ret = s3c_cpufreq_initclks();
+		if (ret)
+			goto out;
+
+		/* get current settings */
+		s3c_cpufreq_getcur(&cpu_cur);
+		s3c_cpufreq_show("cur", &cpu_cur);
+
+		if (cpu_cur.board->auto_io) {
+			ret = s3c_cpufreq_auto_io();
+			if (ret) {
+				printk(KERN_ERR "%s: failed to get io timing\n",
+				       __func__);
+				goto out;
+			}
+		}
+
+		if (cpu_cur.board->need_io && !cpu_cur.info->set_iotiming) {
+			printk(KERN_ERR "%s: no IO support registered\n",
+			       __func__);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		if (!cpu_cur.info->need_pll)
+			cpu_cur.lock_pll = 1;
+
+		s3c_cpufreq_update_loctkime();
+
+		s3c_cpufreq_freq_min(&cpu_cur.max, &cpu_cur.board->max,
+				     &cpu_cur.info->max);
+
+		if (cpu_cur.info->calc_freqtable)
+			s3c_cpufreq_build_freq();
+
+		ret = cpufreq_register_driver(&s3c24xx_driver);
+	}
+
+ out:
+	return ret;
+}
+
+late_initcall(s3c_cpufreq_initcall);
+
+/**
+ * s3c_plltab_register - register CPU PLL table.
+ * @plls: The list of PLL entries.
+ * @plls_no: The size of the PLL entries @plls.
+ *
+ * Register the given set of PLLs with the system.
+ */
+int __init s3c_plltab_register(struct cpufreq_frequency_table *plls,
+			       unsigned int plls_no)
+{
+	struct cpufreq_frequency_table *vals;
+	unsigned int size;
+
+	size = sizeof(struct cpufreq_frequency_table) * (plls_no + 1);
+
+	vals = kmalloc(size, GFP_KERNEL);
+	if (vals) {
+		memcpy(vals, plls, size);
+		pll_reg = vals;
+
+		/* write a terminating entry, we don't store it in the
+		 * table that is stored in the kernel */
+		vals += plls_no;
+		vals->frequency = CPUFREQ_TABLE_END;
+
+		printk(KERN_INFO "cpufreq: %d PLL entries\n", plls_no);
+	} else
+		printk(KERN_ERR "cpufreq: no memory for PLL tables\n");
+
+	return vals ? 0 : -ENOMEM;
+}