Kukjin Kim | dbb8fd3 | 2013-01-21 15:24:34 -0800 | [diff] [blame] | 1 | /* |
Ben Dooks | 22d4239 | 2009-07-30 23:23:33 +0100 | [diff] [blame] | 2 | * Copyright 2008 Simtec Electronics |
| 3 | * http://armlinux.simtec.co.uk/ |
| 4 | * Ben Dooks <ben@simtec.co.uk> |
| 5 | * |
| 6 | * S3C2412 CPU Frequency scalling |
| 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/init.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/interrupt.h> |
| 16 | #include <linux/ioport.h> |
| 17 | #include <linux/cpufreq.h> |
Kay Sievers | 4a858cf | 2011-12-21 16:01:38 -0800 | [diff] [blame] | 18 | #include <linux/device.h> |
Ben Dooks | 22d4239 | 2009-07-30 23:23:33 +0100 | [diff] [blame] | 19 | #include <linux/delay.h> |
| 20 | #include <linux/clk.h> |
| 21 | #include <linux/err.h> |
| 22 | #include <linux/io.h> |
| 23 | |
| 24 | #include <asm/mach/arch.h> |
| 25 | #include <asm/mach/map.h> |
| 26 | |
| 27 | #include <mach/regs-clock.h> |
Viresh Kumar | f023f8d | 2013-04-04 12:54:15 +0000 | [diff] [blame] | 28 | #include <mach/s3c2412.h> |
Ben Dooks | 22d4239 | 2009-07-30 23:23:33 +0100 | [diff] [blame] | 29 | |
| 30 | #include <plat/cpu.h> |
Ben Dooks | 22d4239 | 2009-07-30 23:23:33 +0100 | [diff] [blame] | 31 | #include <plat/cpu-freq-core.h> |
| 32 | |
| 33 | /* our clock resources. */ |
| 34 | static struct clk *xtal; |
| 35 | static struct clk *fclk; |
| 36 | static struct clk *hclk; |
| 37 | static struct clk *armclk; |
| 38 | |
| 39 | /* HDIV: 1, 2, 3, 4, 6, 8 */ |
| 40 | |
| 41 | static int s3c2412_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg) |
| 42 | { |
| 43 | unsigned int hdiv, pdiv, armdiv, dvs; |
| 44 | unsigned long hclk, fclk, armclk, armdiv_clk; |
| 45 | unsigned long hclk_max; |
| 46 | |
| 47 | fclk = cfg->freq.fclk; |
| 48 | armclk = cfg->freq.armclk; |
| 49 | hclk_max = cfg->max.hclk; |
| 50 | |
| 51 | /* We can't run hclk above armclk as at the best we have to |
| 52 | * have armclk and hclk in dvs mode. */ |
| 53 | |
| 54 | if (hclk_max > armclk) |
| 55 | hclk_max = armclk; |
| 56 | |
| 57 | s3c_freq_dbg("%s: fclk=%lu, armclk=%lu, hclk_max=%lu\n", |
| 58 | __func__, fclk, armclk, hclk_max); |
| 59 | s3c_freq_dbg("%s: want f=%lu, arm=%lu, h=%lu, p=%lu\n", |
| 60 | __func__, cfg->freq.fclk, cfg->freq.armclk, |
| 61 | cfg->freq.hclk, cfg->freq.pclk); |
| 62 | |
| 63 | armdiv = fclk / armclk; |
| 64 | |
| 65 | if (armdiv < 1) |
| 66 | armdiv = 1; |
| 67 | if (armdiv > 2) |
| 68 | armdiv = 2; |
| 69 | |
| 70 | cfg->divs.arm_divisor = armdiv; |
| 71 | armdiv_clk = fclk / armdiv; |
| 72 | |
| 73 | hdiv = armdiv_clk / hclk_max; |
| 74 | if (hdiv < 1) |
| 75 | hdiv = 1; |
| 76 | |
| 77 | cfg->freq.hclk = hclk = armdiv_clk / hdiv; |
| 78 | |
| 79 | /* set dvs depending on whether we reached armclk or not. */ |
| 80 | cfg->divs.dvs = dvs = armclk < armdiv_clk; |
| 81 | |
| 82 | /* update the actual armclk we achieved. */ |
| 83 | cfg->freq.armclk = dvs ? hclk : armdiv_clk; |
| 84 | |
| 85 | s3c_freq_dbg("%s: armclk %lu, hclk %lu, armdiv %d, hdiv %d, dvs %d\n", |
| 86 | __func__, armclk, hclk, armdiv, hdiv, cfg->divs.dvs); |
| 87 | |
| 88 | if (hdiv > 4) |
| 89 | goto invalid; |
| 90 | |
| 91 | pdiv = (hclk > cfg->max.pclk) ? 2 : 1; |
| 92 | |
| 93 | if ((hclk / pdiv) > cfg->max.pclk) |
| 94 | pdiv++; |
| 95 | |
| 96 | cfg->freq.pclk = hclk / pdiv; |
| 97 | |
| 98 | s3c_freq_dbg("%s: pdiv %d\n", __func__, pdiv); |
| 99 | |
| 100 | if (pdiv > 2) |
| 101 | goto invalid; |
| 102 | |
| 103 | pdiv *= hdiv; |
| 104 | |
| 105 | /* store the result, and then return */ |
| 106 | |
| 107 | cfg->divs.h_divisor = hdiv * armdiv; |
| 108 | cfg->divs.p_divisor = pdiv * armdiv; |
| 109 | |
| 110 | return 0; |
| 111 | |
Kukjin Kim | dbb8fd3 | 2013-01-21 15:24:34 -0800 | [diff] [blame] | 112 | invalid: |
Ben Dooks | 22d4239 | 2009-07-30 23:23:33 +0100 | [diff] [blame] | 113 | return -EINVAL; |
| 114 | } |
| 115 | |
| 116 | static void s3c2412_cpufreq_setdivs(struct s3c_cpufreq_config *cfg) |
| 117 | { |
| 118 | unsigned long clkdiv; |
| 119 | unsigned long olddiv; |
| 120 | |
| 121 | olddiv = clkdiv = __raw_readl(S3C2410_CLKDIVN); |
| 122 | |
| 123 | /* clear off current clock info */ |
| 124 | |
| 125 | clkdiv &= ~S3C2412_CLKDIVN_ARMDIVN; |
| 126 | clkdiv &= ~S3C2412_CLKDIVN_HDIVN_MASK; |
| 127 | clkdiv &= ~S3C2412_CLKDIVN_PDIVN; |
| 128 | |
| 129 | if (cfg->divs.arm_divisor == 2) |
| 130 | clkdiv |= S3C2412_CLKDIVN_ARMDIVN; |
| 131 | |
| 132 | clkdiv |= ((cfg->divs.h_divisor / cfg->divs.arm_divisor) - 1); |
| 133 | |
| 134 | if (cfg->divs.p_divisor != cfg->divs.h_divisor) |
| 135 | clkdiv |= S3C2412_CLKDIVN_PDIVN; |
| 136 | |
| 137 | s3c_freq_dbg("%s: div %08lx => %08lx\n", __func__, olddiv, clkdiv); |
| 138 | __raw_writel(clkdiv, S3C2410_CLKDIVN); |
| 139 | |
| 140 | clk_set_parent(armclk, cfg->divs.dvs ? hclk : fclk); |
| 141 | } |
| 142 | |
| 143 | static void s3c2412_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg) |
| 144 | { |
| 145 | struct s3c_cpufreq_board *board = cfg->board; |
| 146 | unsigned long refresh; |
| 147 | |
| 148 | s3c_freq_dbg("%s: refresh %u ns, hclk %lu\n", __func__, |
| 149 | board->refresh, cfg->freq.hclk); |
| 150 | |
| 151 | /* Reduce both the refresh time (in ns) and the frequency (in MHz) |
| 152 | * by 10 each to ensure that we do not overflow 32 bit numbers. This |
| 153 | * should work for HCLK up to 133MHz and refresh period up to 30usec. |
| 154 | */ |
| 155 | |
| 156 | refresh = (board->refresh / 10); |
| 157 | refresh *= (cfg->freq.hclk / 100); |
| 158 | refresh /= (1 * 1000 * 1000); /* 10^6 */ |
| 159 | |
| 160 | s3c_freq_dbg("%s: setting refresh 0x%08lx\n", __func__, refresh); |
| 161 | __raw_writel(refresh, S3C2412_REFRESH); |
| 162 | } |
| 163 | |
| 164 | /* set the default cpu frequency information, based on an 200MHz part |
| 165 | * as we have no other way of detecting the speed rating in software. |
| 166 | */ |
| 167 | |
| 168 | static struct s3c_cpufreq_info s3c2412_cpufreq_info = { |
| 169 | .max = { |
| 170 | .fclk = 200000000, |
| 171 | .hclk = 100000000, |
| 172 | .pclk = 50000000, |
| 173 | }, |
| 174 | |
| 175 | .latency = 5000000, /* 5ms */ |
| 176 | |
| 177 | .locktime_m = 150, |
| 178 | .locktime_u = 150, |
| 179 | .locktime_bits = 16, |
| 180 | |
| 181 | .name = "s3c2412", |
| 182 | .set_refresh = s3c2412_cpufreq_setrefresh, |
| 183 | .set_divs = s3c2412_cpufreq_setdivs, |
| 184 | .calc_divs = s3c2412_cpufreq_calcdivs, |
| 185 | |
Ben Dooks | 140780ab | 2009-07-30 23:23:37 +0100 | [diff] [blame] | 186 | .calc_iotiming = s3c2412_iotiming_calc, |
| 187 | .set_iotiming = s3c2412_iotiming_set, |
| 188 | .get_iotiming = s3c2412_iotiming_get, |
| 189 | |
Ben Dooks | e6d197a | 2009-07-30 23:23:42 +0100 | [diff] [blame] | 190 | .debug_io_show = s3c_cpufreq_debugfs_call(s3c2412_iotiming_debugfs), |
Ben Dooks | 22d4239 | 2009-07-30 23:23:33 +0100 | [diff] [blame] | 191 | }; |
| 192 | |
Heiko Stuebner | 04511a6 | 2012-01-27 15:35:25 +0900 | [diff] [blame] | 193 | static int s3c2412_cpufreq_add(struct device *dev, |
| 194 | struct subsys_interface *sif) |
Ben Dooks | 22d4239 | 2009-07-30 23:23:33 +0100 | [diff] [blame] | 195 | { |
| 196 | unsigned long fclk_rate; |
| 197 | |
| 198 | hclk = clk_get(NULL, "hclk"); |
| 199 | if (IS_ERR(hclk)) { |
| 200 | printk(KERN_ERR "%s: cannot find hclk clock\n", __func__); |
| 201 | return -ENOENT; |
| 202 | } |
| 203 | |
| 204 | fclk = clk_get(NULL, "fclk"); |
| 205 | if (IS_ERR(fclk)) { |
| 206 | printk(KERN_ERR "%s: cannot find fclk clock\n", __func__); |
| 207 | goto err_fclk; |
| 208 | } |
| 209 | |
| 210 | fclk_rate = clk_get_rate(fclk); |
| 211 | if (fclk_rate > 200000000) { |
| 212 | printk(KERN_INFO |
| 213 | "%s: fclk %ld MHz, assuming 266MHz capable part\n", |
| 214 | __func__, fclk_rate / 1000000); |
| 215 | s3c2412_cpufreq_info.max.fclk = 266000000; |
| 216 | s3c2412_cpufreq_info.max.hclk = 133000000; |
| 217 | s3c2412_cpufreq_info.max.pclk = 66000000; |
| 218 | } |
| 219 | |
| 220 | armclk = clk_get(NULL, "armclk"); |
| 221 | if (IS_ERR(armclk)) { |
| 222 | printk(KERN_ERR "%s: cannot find arm clock\n", __func__); |
| 223 | goto err_armclk; |
| 224 | } |
| 225 | |
| 226 | xtal = clk_get(NULL, "xtal"); |
| 227 | if (IS_ERR(xtal)) { |
| 228 | printk(KERN_ERR "%s: cannot find xtal clock\n", __func__); |
| 229 | goto err_xtal; |
| 230 | } |
| 231 | |
| 232 | return s3c_cpufreq_register(&s3c2412_cpufreq_info); |
| 233 | |
| 234 | err_xtal: |
| 235 | clk_put(armclk); |
| 236 | err_armclk: |
| 237 | clk_put(fclk); |
| 238 | err_fclk: |
| 239 | clk_put(hclk); |
| 240 | |
| 241 | return -ENOENT; |
| 242 | } |
| 243 | |
Kay Sievers | 4a858cf | 2011-12-21 16:01:38 -0800 | [diff] [blame] | 244 | static struct subsys_interface s3c2412_cpufreq_interface = { |
| 245 | .name = "s3c2412_cpufreq", |
| 246 | .subsys = &s3c2412_subsys, |
| 247 | .add_dev = s3c2412_cpufreq_add, |
Ben Dooks | 22d4239 | 2009-07-30 23:23:33 +0100 | [diff] [blame] | 248 | }; |
| 249 | |
| 250 | static int s3c2412_cpufreq_init(void) |
| 251 | { |
Kay Sievers | 4a858cf | 2011-12-21 16:01:38 -0800 | [diff] [blame] | 252 | return subsys_interface_register(&s3c2412_cpufreq_interface); |
Ben Dooks | 22d4239 | 2009-07-30 23:23:33 +0100 | [diff] [blame] | 253 | } |
Ben Dooks | 22d4239 | 2009-07-30 23:23:33 +0100 | [diff] [blame] | 254 | arch_initcall(s3c2412_cpufreq_init); |