LXR linux/arch/arm/mach-s3c24xx/cpufreq-utils.c

   1// SPDX-License-Identifier: GPL-2.0
   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#include <linux/kernel.h>
  10#include <linux/errno.h>
  11#include <linux/cpufreq.h>
  12#include <linux/io.h>
  13#include <linux/clk.h>
  14
  15#include <mach/map.h>
  16#include <mach/regs-clock.h>
  17
  18#include <plat/cpu-freq-core.h>
  19
  20#include "regs-mem.h"
  21
  22/**
  23 * s3c2410_cpufreq_setrefresh - set SDRAM refresh value
  24 * @cfg: The frequency configuration
  25 *
  26 * Set the SDRAM refresh value appropriately for the configured
  27 * frequency.
  28 */
  29void s3c2410_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
  30{
  31        struct s3c_cpufreq_board *board = cfg->board;
  32        unsigned long refresh;
  33        unsigned long refval;
  34
  35        /* Reduce both the refresh time (in ns) and the frequency (in MHz)
  36         * down to ensure that we do not overflow 32 bit numbers.
  37         *
  38         * This should work for HCLK up to 133MHz and refresh period up
  39         * to 30usec.
  40         */
  41
  42        refresh = (cfg->freq.hclk / 100) * (board->refresh / 10);
  43        refresh = DIV_ROUND_UP(refresh, (1000 * 1000)); /* apply scale  */
  44        refresh = (1 << 11) + 1 - refresh;
  45
  46        s3c_freq_dbg("%s: refresh value %lu\n", __func__, refresh);
  47
  48        refval = __raw_readl(S3C2410_REFRESH);
  49        refval &= ~((1 << 12) - 1);
  50        refval |= refresh;
  51        __raw_writel(refval, S3C2410_REFRESH);
  52}
  53
  54/**
  55 * s3c2410_set_fvco - set the PLL value
  56 * @cfg: The frequency configuration
  57 */
  58void s3c2410_set_fvco(struct s3c_cpufreq_config *cfg)
  59{
  60        if (!IS_ERR(cfg->mpll))
  61                clk_set_rate(cfg->mpll, cfg->pll.frequency);
  62}
  63