ARM: S3C24XX: CPUFREQ: Add core support.

Add the core of the support for enabling the CPUFreq driver on
all S3C24XX based systems.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

3 files changed, 889 insertions, 0 deletions

diff --git a/arch/arm/plat-s3c24xx/Makefile b/arch/arm/plat-s3c24xx/Makefile
index 579a165c2827..1f6add552bd0 100644
--- a/arch/arm/plat-s3c24xx/Makefile
+++ b/arch/arm/plat-s3c24xx/Makefile
@@ -20,6 +20,8 @@ obj-y				+= gpiolib.o
 obj-y				+= clock.o
 obj-$(CONFIG_S3C24XX_DCLK)	+= clock-dclk.o
 
+obj-$(CONFIG_CPU_FREQ_S3C24XX)	+= cpu-freq.o
+
 # Architecture dependant builds
 
 obj-$(CONFIG_CPU_S3C244X)	+= s3c244x.o
diff --git a/arch/arm/plat-s3c24xx/cpu-freq.c b/arch/arm/plat-s3c24xx/cpu-freq.c
new file mode 100644
index 000000000000..40ff7e2569dc
--- /dev/null
+++ b/arch/arm/plat-s3c24xx/cpu-freq.c
@@ -0,0 +1,704 @@
+/* linux/arch/arm/plat-s3c24xx/cpu-freq.c
+ *
+ * Copyright (c) 2006,2007,2008 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/sysdev.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.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;
+
+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.cpu = 0;
+	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 */
+
+	if (policy)
+		cpufreq_notify_transition(&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 */
+	if (policy)
+		cpufreq_notify_transition(&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, pm_message_t pmsg)
+{
+	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 immediatley 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;
+}
diff --git a/arch/arm/plat-s3c24xx/include/plat/cpu-freq-core.h b/arch/arm/plat-s3c24xx/include/plat/cpu-freq-core.h
new file mode 100644
index 000000000000..e078821b3605
--- /dev/null
+++ b/arch/arm/plat-s3c24xx/include/plat/cpu-freq-core.h
@@ -0,0 +1,183 @@
+/* arch/arm/plat-s3c/include/plat/cpu-freq.h
+ *
+ * Copyright (c) 2006,2007,2009 Simtec Electronics
+ *	http://armlinux.simtec.co.uk/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C CPU frequency scaling support - core 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 <plat/cpu-freq.h>
+
+#define MAX_BANKS (8)
+#define S3C2412_MAX_IO	(8)
+
+/**
+ * struct s3c2410_iobank_timing - IO bank timings for S3C2410 style timings
+ * @bankcon: The cached version of settings in this structure.
+ * @tacp:
+ * @tacs: Time from address valid to nCS asserted.
+ * @tcos: Time from nCS asserted to nOE or nWE asserted.
+ * @tacc: Time that nOE or nWE is asserted.
+ * @tcoh: Time nCS is held after nOE or nWE are released.
+ * @tcah: Time address is held for after
+ * @nwait_en: Whether nWAIT is enabled for this bank.
+ *
+ * This structure represents the IO timings for a S3C2410 style IO bank
+ * used by the CPU frequency support if it needs to change the settings
+ * of the IO.
+ */
+struct s3c2410_iobank_timing {
+	unsigned long	bankcon;
+	unsigned int	tacp;
+	unsigned int	tacs;
+	unsigned int	tcos;
+	unsigned int	tacc;
+	unsigned int	tcoh;		/* nCS hold afrer nOE/nWE */
+	unsigned int	tcah;		/* Address hold after nCS */
+	unsigned char	nwait_en;	/* nWait enabled for bank. */
+};
+
+union s3c_iobank {
+	  struct s3c2410_iobank_timing	*io_2410;
+};
+
+/**
+ * struct s3c_iotimings - Chip IO timings holder
+ * @bank: The timings for each IO bank.
+ */
+struct s3c_iotimings {
+	union s3c_iobank	bank[MAX_BANKS];
+};
+
+/**
+ * struct s3c_plltab - PLL table information.
+ * @vals: List of PLL values.
+ * @size: Size of the PLL table @vals.
+ */
+struct s3c_plltab {
+	struct s3c_pllval	*vals;
+	int			 size;
+};
+
+/**
+ * struct s3c_cpufreq_info - Information for the CPU frequency driver.
+ * @name: The name of this implementation.
+ * @max: The maximum frequencies for the system.
+ * @latency: Transition latency to give to cpufreq.
+ * @locktime_m: The lock-time in uS for the MPLL.
+ * @locktime_u: The lock-time in uS for the UPLL.
+ * @locttime_bits: The number of bits each LOCKTIME field.
+ * @need_pll: Set if this driver needs to change the PLL values to acheive
+ *	any frequency changes. This is really only need by devices like the
+ *	S3C2410 where there is no or limited divider between the PLL and the
+ *	ARMCLK.
+ * @resume_clocks: Update the clocks on resume.
+ * @get_iotiming: Get the current IO timing data, mainly for use at start.
+ * @set_iotiming: Update the IO timings from the cached copies calculated
+ *	from the @calc_iotiming entry when changing the frequency.
+ * @calc_iotiming: Calculate and update the cached copies of the IO timings
+ *	from the newly calculated frequencies.
+ * @calc_freqtable: Calculate (fill in) the given frequency table from the
+ *	current frequency configuration. If the table passed in is NULL,
+ *	then the return is the number of elements to be filled for allocation
+ *	of the table.
+ * @set_refresh: Set the memory refresh configuration.
+ * @set_fvco: Set the PLL frequencies.
+ * @set_divs: Update the clock divisors.
+ * @calc_divs: Calculate the clock divisors.
+ */
+struct s3c_cpufreq_info {
+	const char		*name;
+	struct s3c_freq		max;
+
+	unsigned int		latency;
+
+	unsigned int		locktime_m;
+	unsigned int		locktime_u;
+	unsigned char		locktime_bits;
+
+	unsigned int		need_pll:1;
+
+	/* driver routines */
+
+	void		(*resume_clocks)(void);
+
+	int		(*get_iotiming)(struct s3c_cpufreq_config *cfg,
+					struct s3c_iotimings *timings);
+
+	void		(*set_iotiming)(struct s3c_cpufreq_config *cfg,
+					struct s3c_iotimings *timings);
+
+	int		(*calc_iotiming)(struct s3c_cpufreq_config *cfg,
+					 struct s3c_iotimings *timings);
+
+	int		(*calc_freqtable)(struct s3c_cpufreq_config *cfg,
+					  struct cpufreq_frequency_table *t,
+					  size_t table_size);
+
+	void		(*set_refresh)(struct s3c_cpufreq_config *cfg);
+	void		(*set_fvco)(struct s3c_cpufreq_config *cfg);
+	void		(*set_divs)(struct s3c_cpufreq_config *cfg);
+	int		(*calc_divs)(struct s3c_cpufreq_config *cfg);
+};
+
+extern int s3c_cpufreq_register(struct s3c_cpufreq_info *info);
+
+extern int s3c_plltab_register(struct cpufreq_frequency_table *plls, unsigned int plls_no);
+
+/* Useful utility functions. */
+
+extern struct clk *s3c_cpufreq_clk_get(struct device *, const char *);
+
+/* S3C2410 and compatible exported functions */
+
+extern void s3c2410_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg);
+
+extern int s3c2410_iotiming_calc(struct s3c_cpufreq_config *cfg,
+				 struct s3c_iotimings *iot);
+
+extern int s3c2410_iotiming_get(struct s3c_cpufreq_config *cfg,
+				struct s3c_iotimings *timings);
+
+extern void s3c2410_iotiming_set(struct s3c_cpufreq_config *cfg,
+				 struct s3c_iotimings *iot);
+
+extern void s3c2410_set_fvco(struct s3c_cpufreq_config *cfg);
+
+#ifdef CONFIG_CPU_FREQ_S3C24XX_DEBUG
+#define s3c_freq_dbg(x...) printk(KERN_INFO x)
+#else
+#define s3c_freq_dbg(x...) do { if (0) printk(x); } while (0)
+#endif /* CONFIG_CPU_FREQ_S3C24XX_DEBUG */
+
+#ifdef CONFIG_CPU_FREQ_S3C24XX_IODEBUG
+#define s3c_freq_iodbg(x...) printk(KERN_INFO x)
+#else
+#define s3c_freq_iodbg(x...) do { if (0) printk(x); } while (0)
+#endif /* CONFIG_CPU_FREQ_S3C24XX_IODEBUG */
+
+static inline int s3c_cpufreq_addfreq(struct cpufreq_frequency_table *table,
+				      int index, size_t table_size,
+				      unsigned int freq)
+{
+	if (index < 0)
+		return index;
+
+	if (table) {
+		if (index >= table_size)
+			return -ENOMEM;
+
+		s3c_freq_dbg("%s: { %d = %u kHz }\n",
+			     __func__, index, freq);
+
+		table[index].index = index;
+		table[index].frequency = freq;
+	}
+
+	return index + 1;
+}