LXR linux/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c

   1/* linux/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c
   2 *
   3 * Copyright (c) 2009 Simtec Electronics
   4 *      http://armlinux.simtec.co.uk/
   5 *      Ben Dooks <ben@simtec.co.uk>
   6 *
   7 * S3C24XX CPU Frequency scaling - utils for S3C2410/S3C2440/S3C2442
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License version 2 as
  11 * published by the Free Software Foundation.
  12*/
  13
  14#include <linux/kernel.h>
  15#include <linux/errno.h>
  16#include <linux/cpufreq.h>
  17#include <linux/io.h>
  18
  19#include <mach/map.h>
  20#include <mach/regs-mem.h>
  21#include <mach/regs-clock.h>
  22
  23#include <plat/cpu-freq-core.h>
  24
  25/**
  26 * s3c2410_cpufreq_setrefresh - set SDRAM refresh value
  27 * @cfg: The frequency configuration
  28 *
  29 * Set the SDRAM refresh value appropriately for the configured
  30 * frequency.
  31 */
  32void s3c2410_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
  33{
  34        struct s3c_cpufreq_board *board = cfg->board;
  35        unsigned long refresh;
  36        unsigned long refval;
  37
  38        /* Reduce both the refresh time (in ns) and the frequency (in MHz)
  39         * down to ensure that we do not overflow 32 bit numbers.
  40         *
  41         * This should work for HCLK up to 133MHz and refresh period up
  42         * to 30usec.
  43         */
  44
  45        refresh = (cfg->freq.hclk / 100) * (board->refresh / 10);
  46        refresh = DIV_ROUND_UP(refresh, (1000 * 1000)); /* apply scale  */
  47        refresh = (1 << 11) + 1 - refresh;
  48
  49        s3c_freq_dbg("%s: refresh value %lu\n", __func__, refresh);
  50
  51        refval = __raw_readl(S3C2410_REFRESH);
  52        refval &= ~((1 << 12) - 1);
  53        refval |= refresh;
  54        __raw_writel(refval, S3C2410_REFRESH);
  55}
  56
  57/**
  58 * s3c2410_set_fvco - set the PLL value
  59 * @cfg: The frequency configuration
  60 */
  61void s3c2410_set_fvco(struct s3c_cpufreq_config *cfg)
  62{
  63        __raw_writel(cfg->pll.index, S3C2410_MPLLCON);
  64}
  65