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>

3 files changed, 72 insertions, 0 deletions

diff --git a/arch/arm/plat-s3c24xx/Kconfig b/arch/arm/plat-s3c24xx/Kconfig
index d82d30c2f05..a547c79ed6c 100644
--- a/arch/arm/plat-s3c24xx/Kconfig
+++ b/arch/arm/plat-s3c24xx/Kconfig
@@ -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
diff --git a/arch/arm/plat-s3c24xx/Makefile b/arch/arm/plat-s3c24xx/Makefile
index 6f9afd13ab4..b28fe9cb0e5 100644
--- a/arch/arm/plat-s3c24xx/Makefile
+++ b/arch/arm/plat-s3c24xx/Makefile
@@ -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
diff --git a/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c b/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c
new file mode 100644
index 00000000000..43ea80190d8
--- /dev/null
+++ b/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c
@@ -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);
+}