| Ben Dooks | a24c091 | 2009-07-30 23:23:27 +0100 | [diff] [blame] | 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 | */ |
| 32 | void 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 | */ |
| 61 | void s3c2410_set_fvco(struct s3c_cpufreq_config *cfg) |
| 62 | { |
| 63 | __raw_writel(cfg->pll.index, S3C2410_MPLLCON); |
| 64 | } |