a24c091db9
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>
64 lines
1.7 KiB
C
64 lines
1.7 KiB
C
/* linux/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c
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*
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* Copyright (c) 2009 Simtec Electronics
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* http://armlinux.simtec.co.uk/
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* Ben Dooks <ben@simtec.co.uk>
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*
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* S3C24XX CPU Frequency scaling - utils for S3C2410/S3C2440/S3C2442
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/cpufreq.h>
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#include <linux/io.h>
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#include <mach/map.h>
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#include <mach/regs-mem.h>
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#include <mach/regs-clock.h>
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#include <plat/cpu-freq-core.h>
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/**
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* s3c2410_cpufreq_setrefresh - set SDRAM refresh value
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* @cfg: The frequency configuration
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*
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* Set the SDRAM refresh value appropriately for the configured
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* frequency.
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*/
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void s3c2410_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
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{
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struct s3c_cpufreq_board *board = cfg->board;
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unsigned long refresh;
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unsigned long refval;
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/* Reduce both the refresh time (in ns) and the frequency (in MHz)
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* down to ensure that we do not overflow 32 bit numbers.
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*
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* This should work for HCLK up to 133MHz and refresh period up
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* to 30usec.
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*/
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refresh = (cfg->freq.hclk / 100) * (board->refresh / 10);
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refresh = DIV_ROUND_UP(refresh, (1000 * 1000)); /* apply scale */
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refresh = (1 << 11) + 1 - refresh;
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s3c_freq_dbg("%s: refresh value %lu\n", __func__, refresh);
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refval = __raw_readl(S3C2410_REFRESH);
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refval &= ~((1 << 12) - 1);
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refval |= refresh;
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__raw_writel(refval, S3C2410_REFRESH);
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}
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/**
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* s3c2410_set_fvco - set the PLL value
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* @cfg: The frequency configuration
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*/
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void s3c2410_set_fvco(struct s3c_cpufreq_config *cfg)
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{
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__raw_writel(cfg->pll.index, S3C2410_MPLLCON);
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}
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