diff options
Diffstat (limited to 'arch/arm/mach-s3c24xx/cpufreq-utils.c')
-rw-r--r-- | arch/arm/mach-s3c24xx/cpufreq-utils.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/arch/arm/mach-s3c24xx/cpufreq-utils.c b/arch/arm/mach-s3c24xx/cpufreq-utils.c new file mode 100644 index 000000000000..89e4e2b7a82e --- /dev/null +++ b/arch/arm/mach-s3c24xx/cpufreq-utils.c | |||
@@ -0,0 +1,63 @@ | |||
1 | /* | ||
2 | * Copyright (c) 2009 Simtec Electronics | ||
3 | * http://armlinux.simtec.co.uk/ | ||
4 | * Ben Dooks <ben@simtec.co.uk> | ||
5 | * | ||
6 | * S3C24XX CPU Frequency scaling - utils for S3C2410/S3C2440/S3C2442 | ||
7 | * | ||
8 | * This program is free software; you can redistribute it and/or modify | ||
9 | * it under the terms of the GNU General Public License version 2 as | ||
10 | * published by the Free Software Foundation. | ||
11 | */ | ||
12 | |||
13 | #include <linux/kernel.h> | ||
14 | #include <linux/errno.h> | ||
15 | #include <linux/cpufreq.h> | ||
16 | #include <linux/io.h> | ||
17 | |||
18 | #include <mach/map.h> | ||
19 | #include <mach/regs-mem.h> | ||
20 | #include <mach/regs-clock.h> | ||
21 | |||
22 | #include <plat/cpu-freq-core.h> | ||
23 | |||
24 | /** | ||
25 | * s3c2410_cpufreq_setrefresh - set SDRAM refresh value | ||
26 | * @cfg: The frequency configuration | ||
27 | * | ||
28 | * Set the SDRAM refresh value appropriately for the configured | ||
29 | * frequency. | ||
30 | */ | ||
31 | void s3c2410_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg) | ||
32 | { | ||
33 | struct s3c_cpufreq_board *board = cfg->board; | ||
34 | unsigned long refresh; | ||
35 | unsigned long refval; | ||
36 | |||
37 | /* Reduce both the refresh time (in ns) and the frequency (in MHz) | ||
38 | * down to ensure that we do not overflow 32 bit numbers. | ||
39 | * | ||
40 | * This should work for HCLK up to 133MHz and refresh period up | ||
41 | * to 30usec. | ||
42 | */ | ||
43 | |||
44 | refresh = (cfg->freq.hclk / 100) * (board->refresh / 10); | ||
45 | refresh = DIV_ROUND_UP(refresh, (1000 * 1000)); /* apply scale */ | ||
46 | refresh = (1 << 11) + 1 - refresh; | ||
47 | |||
48 | s3c_freq_dbg("%s: refresh value %lu\n", __func__, refresh); | ||
49 | |||
50 | refval = __raw_readl(S3C2410_REFRESH); | ||
51 | refval &= ~((1 << 12) - 1); | ||
52 | refval |= refresh; | ||
53 | __raw_writel(refval, S3C2410_REFRESH); | ||
54 | } | ||
55 | |||
56 | /** | ||
57 | * s3c2410_set_fvco - set the PLL value | ||
58 | * @cfg: The frequency configuration | ||
59 | */ | ||
60 | void s3c2410_set_fvco(struct s3c_cpufreq_config *cfg) | ||
61 | { | ||
62 | __raw_writel(cfg->pll.index, S3C2410_MPLLCON); | ||
63 | } | ||