diff options
Diffstat (limited to 'arch/arm/mach-s3c24xx/cpufreq-utils.c')
| -rw-r--r-- | arch/arm/mach-s3c24xx/cpufreq-utils.c | 64 | 
1 files changed, 64 insertions, 0 deletions
diff --git a/arch/arm/mach-s3c24xx/cpufreq-utils.c b/arch/arm/mach-s3c24xx/cpufreq-utils.c new file mode 100644 index 00000000000..ddd8280e387 --- /dev/null +++ b/arch/arm/mach-s3c24xx/cpufreq-utils.c @@ -0,0 +1,64 @@ +/* + * 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-clock.h> + +#include <plat/cpu-freq-core.h> + +#include "regs-mem.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); +}  |