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authorBen Dooks <ben@simtec.co.uk>2009-07-30 23:23:27 +0100
committerBen Dooks <ben-linux@fluff.org>2009-07-30 23:22:52 +0100
commita24c091db988551e2c350cfde9eb80ab6e791ffb (patch)
tree487a86d71ed0a97c27c25de9e618e7db25066c8e /arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c
parent831a6fcb9393960b35173fa2e0f835b710152fff (diff)
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>
Diffstat (limited to 'arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c')
-rw-r--r--arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c64
1 files changed, 64 insertions, 0 deletions
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
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+++ 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);
+}