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 d82d30c2f059..a547c79ed6ce 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 6f9afd13ab4f..b28fe9cb0e5e 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 000000000000..43ea80190d87
--- /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);
+}