1 /* 2 * CPU frequency scaling for OMAP using OPP information 3 * 4 * Copyright (C) 2005 Nokia Corporation 5 * Written by Tony Lindgren <tony@atomide.com> 6 * 7 * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King 8 * 9 * Copyright (C) 2007-2011 Texas Instruments, Inc. 10 * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 as 14 * published by the Free Software Foundation. 15 */ 16 #include <linux/types.h> 17 #include <linux/kernel.h> 18 #include <linux/sched.h> 19 #include <linux/cpufreq.h> 20 #include <linux/delay.h> 21 #include <linux/init.h> 22 #include <linux/err.h> 23 #include <linux/clk.h> 24 #include <linux/io.h> 25 #include <linux/opp.h> 26 #include <linux/cpu.h> 27 #include <linux/module.h> 28 29 #include <asm/system.h> 30 #include <asm/smp_plat.h> 31 #include <asm/cpu.h> 32 33 #include <plat/clock.h> 34 #include <plat/omap-pm.h> 35 #include <plat/common.h> 36 #include <plat/omap_device.h> 37 38 #include <mach/hardware.h> 39 40 #ifdef CONFIG_SMP 41 struct lpj_info { 42 unsigned long ref; 43 unsigned int freq; 44 }; 45 46 static DEFINE_PER_CPU(struct lpj_info, lpj_ref); 47 static struct lpj_info global_lpj_ref; 48 #endif 49 50 static struct cpufreq_frequency_table *freq_table; 51 static atomic_t freq_table_users = ATOMIC_INIT(0); 52 static struct clk *mpu_clk; 53 static char *mpu_clk_name; 54 static struct device *mpu_dev; 55 56 static int omap_verify_speed(struct cpufreq_policy *policy) 57 { 58 if (!freq_table) 59 return -EINVAL; 60 return cpufreq_frequency_table_verify(policy, freq_table); 61 } 62 63 static unsigned int omap_getspeed(unsigned int cpu) 64 { 65 unsigned long rate; 66 67 if (cpu >= NR_CPUS) 68 return 0; 69 70 rate = clk_get_rate(mpu_clk) / 1000; 71 return rate; 72 } 73 74 static int omap_target(struct cpufreq_policy *policy, 75 unsigned int target_freq, 76 unsigned int relation) 77 { 78 unsigned int i; 79 int ret = 0; 80 struct cpufreq_freqs freqs; 81 82 if (!freq_table) { 83 dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__, 84 policy->cpu); 85 return -EINVAL; 86 } 87 88 ret = cpufreq_frequency_table_target(policy, freq_table, target_freq, 89 relation, &i); 90 if (ret) { 91 dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n", 92 __func__, policy->cpu, target_freq, ret); 93 return ret; 94 } 95 freqs.new = freq_table[i].frequency; 96 if (!freqs.new) { 97 dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__, 98 policy->cpu, target_freq); 99 return -EINVAL; 100 } 101 102 freqs.old = omap_getspeed(policy->cpu); 103 freqs.cpu = policy->cpu; 104 105 if (freqs.old == freqs.new && policy->cur == freqs.new) 106 return ret; 107 108 /* notifiers */ 109 for_each_cpu(i, policy->cpus) { 110 freqs.cpu = i; 111 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); 112 } 113 114 #ifdef CONFIG_CPU_FREQ_DEBUG 115 pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new); 116 #endif 117 118 ret = clk_set_rate(mpu_clk, freqs.new * 1000); 119 freqs.new = omap_getspeed(policy->cpu); 120 121 #ifdef CONFIG_SMP 122 /* 123 * Note that loops_per_jiffy is not updated on SMP systems in 124 * cpufreq driver. So, update the per-CPU loops_per_jiffy value 125 * on frequency transition. We need to update all dependent CPUs. 126 */ 127 for_each_cpu(i, policy->cpus) { 128 struct lpj_info *lpj = &per_cpu(lpj_ref, i); 129 if (!lpj->freq) { 130 lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy; 131 lpj->freq = freqs.old; 132 } 133 134 per_cpu(cpu_data, i).loops_per_jiffy = 135 cpufreq_scale(lpj->ref, lpj->freq, freqs.new); 136 } 137 138 /* And don't forget to adjust the global one */ 139 if (!global_lpj_ref.freq) { 140 global_lpj_ref.ref = loops_per_jiffy; 141 global_lpj_ref.freq = freqs.old; 142 } 143 loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq, 144 freqs.new); 145 #endif 146 147 /* notifiers */ 148 for_each_cpu(i, policy->cpus) { 149 freqs.cpu = i; 150 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); 151 } 152 153 return ret; 154 } 155 156 static inline void freq_table_free(void) 157 { 158 if (atomic_dec_and_test(&freq_table_users)) 159 opp_free_cpufreq_table(mpu_dev, &freq_table); 160 } 161 162 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy) 163 { 164 int result = 0; 165 166 mpu_clk = clk_get(NULL, mpu_clk_name); 167 if (IS_ERR(mpu_clk)) 168 return PTR_ERR(mpu_clk); 169 170 if (policy->cpu >= NR_CPUS) { 171 result = -EINVAL; 172 goto fail_ck; 173 } 174 175 policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu); 176 177 if (atomic_inc_return(&freq_table_users) == 1) 178 result = opp_init_cpufreq_table(mpu_dev, &freq_table); 179 180 if (result) { 181 dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n", 182 __func__, policy->cpu, result); 183 goto fail_ck; 184 } 185 186 result = cpufreq_frequency_table_cpuinfo(policy, freq_table); 187 if (result) 188 goto fail_table; 189 190 cpufreq_frequency_table_get_attr(freq_table, policy->cpu); 191 192 policy->min = policy->cpuinfo.min_freq; 193 policy->max = policy->cpuinfo.max_freq; 194 policy->cur = omap_getspeed(policy->cpu); 195 196 /* 197 * On OMAP SMP configuartion, both processors share the voltage 198 * and clock. So both CPUs needs to be scaled together and hence 199 * needs software co-ordination. Use cpufreq affected_cpus 200 * interface to handle this scenario. Additional is_smp() check 201 * is to keep SMP_ON_UP build working. 202 */ 203 if (is_smp()) { 204 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY; 205 cpumask_setall(policy->cpus); 206 } 207 208 /* FIXME: what's the actual transition time? */ 209 policy->cpuinfo.transition_latency = 300 * 1000; 210 211 return 0; 212 213 fail_table: 214 freq_table_free(); 215 fail_ck: 216 clk_put(mpu_clk); 217 return result; 218 } 219 220 static int omap_cpu_exit(struct cpufreq_policy *policy) 221 { 222 freq_table_free(); 223 clk_put(mpu_clk); 224 return 0; 225 } 226 227 static struct freq_attr *omap_cpufreq_attr[] = { 228 &cpufreq_freq_attr_scaling_available_freqs, 229 NULL, 230 }; 231 232 static struct cpufreq_driver omap_driver = { 233 .flags = CPUFREQ_STICKY, 234 .verify = omap_verify_speed, 235 .target = omap_target, 236 .get = omap_getspeed, 237 .init = omap_cpu_init, 238 .exit = omap_cpu_exit, 239 .name = "omap", 240 .attr = omap_cpufreq_attr, 241 }; 242 243 static int __init omap_cpufreq_init(void) 244 { 245 if (cpu_is_omap24xx()) 246 mpu_clk_name = "virt_prcm_set"; 247 else if (cpu_is_omap34xx()) 248 mpu_clk_name = "dpll1_ck"; 249 else if (cpu_is_omap44xx()) 250 mpu_clk_name = "dpll_mpu_ck"; 251 252 if (!mpu_clk_name) { 253 pr_err("%s: unsupported Silicon?\n", __func__); 254 return -EINVAL; 255 } 256 257 mpu_dev = omap_device_get_by_hwmod_name("mpu"); 258 if (!mpu_dev) { 259 pr_warning("%s: unable to get the mpu device\n", __func__); 260 return -EINVAL; 261 } 262 263 return cpufreq_register_driver(&omap_driver); 264 } 265 266 static void __exit omap_cpufreq_exit(void) 267 { 268 cpufreq_unregister_driver(&omap_driver); 269 } 270 271 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs"); 272 MODULE_LICENSE("GPL"); 273 module_init(omap_cpufreq_init); 274 module_exit(omap_cpufreq_exit); 275