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