1 /* 2 * This file was based upon code in Powertweak Linux (http://powertweak.sf.net) 3 * (C) 2000-2003 Dave Jones, Arjan van de Ven, Janne Pänkälä, 4 * Dominik Brodowski. 5 * 6 * Licensed under the terms of the GNU GPL License version 2. 7 * 8 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous* 9 */ 10 11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 12 13 #include <linux/kernel.h> 14 #include <linux/module.h> 15 #include <linux/init.h> 16 #include <linux/cpufreq.h> 17 #include <linux/ioport.h> 18 #include <linux/timex.h> 19 #include <linux/io.h> 20 21 #include <asm/cpu_device_id.h> 22 #include <asm/msr.h> 23 24 #define POWERNOW_IOPORT 0xfff0 /* it doesn't matter where, as long 25 as it is unused */ 26 27 static unsigned int busfreq; /* FSB, in 10 kHz */ 28 static unsigned int max_multiplier; 29 30 static unsigned int param_busfreq = 0; 31 static unsigned int param_max_multiplier = 0; 32 33 module_param_named(max_multiplier, param_max_multiplier, uint, S_IRUGO); 34 MODULE_PARM_DESC(max_multiplier, "Maximum multiplier (allowed values: 20 30 35 40 45 50 55 60)"); 35 36 module_param_named(bus_frequency, param_busfreq, uint, S_IRUGO); 37 MODULE_PARM_DESC(bus_frequency, "Bus frequency in kHz"); 38 39 /* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */ 40 static struct cpufreq_frequency_table clock_ratio[] = { 41 {0, 60, /* 110 -> 6.0x */ 0}, 42 {0, 55, /* 011 -> 5.5x */ 0}, 43 {0, 50, /* 001 -> 5.0x */ 0}, 44 {0, 45, /* 000 -> 4.5x */ 0}, 45 {0, 40, /* 010 -> 4.0x */ 0}, 46 {0, 35, /* 111 -> 3.5x */ 0}, 47 {0, 30, /* 101 -> 3.0x */ 0}, 48 {0, 20, /* 100 -> 2.0x */ 0}, 49 {0, 0, CPUFREQ_TABLE_END} 50 }; 51 52 static const u8 index_to_register[8] = { 6, 3, 1, 0, 2, 7, 5, 4 }; 53 static const u8 register_to_index[8] = { 3, 2, 4, 1, 7, 6, 0, 5 }; 54 55 static const struct { 56 unsigned freq; 57 unsigned mult; 58 } usual_frequency_table[] = { 59 { 350000, 35 }, // 100 * 3.5 60 { 400000, 40 }, // 100 * 4 61 { 450000, 45 }, // 100 * 4.5 62 { 475000, 50 }, // 95 * 5 63 { 500000, 50 }, // 100 * 5 64 { 506250, 45 }, // 112.5 * 4.5 65 { 533500, 55 }, // 97 * 5.5 66 { 550000, 55 }, // 100 * 5.5 67 { 562500, 50 }, // 112.5 * 5 68 { 570000, 60 }, // 95 * 6 69 { 600000, 60 }, // 100 * 6 70 { 618750, 55 }, // 112.5 * 5.5 71 { 660000, 55 }, // 120 * 5.5 72 { 675000, 60 }, // 112.5 * 6 73 { 720000, 60 }, // 120 * 6 74 }; 75 76 #define FREQ_RANGE 3000 77 78 /** 79 * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier 80 * 81 * Returns the current setting of the frequency multiplier. Core clock 82 * speed is frequency of the Front-Side Bus multiplied with this value. 83 */ 84 static int powernow_k6_get_cpu_multiplier(void) 85 { 86 unsigned long invalue = 0; 87 u32 msrval; 88 89 local_irq_disable(); 90 91 msrval = POWERNOW_IOPORT + 0x1; 92 wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */ 93 invalue = inl(POWERNOW_IOPORT + 0x8); 94 msrval = POWERNOW_IOPORT + 0x0; 95 wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */ 96 97 local_irq_enable(); 98 99 return clock_ratio[register_to_index[(invalue >> 5)&7]].driver_data; 100 } 101 102 static void powernow_k6_set_cpu_multiplier(unsigned int best_i) 103 { 104 unsigned long outvalue, invalue; 105 unsigned long msrval; 106 unsigned long cr0; 107 108 /* we now need to transform best_i to the BVC format, see AMD#23446 */ 109 110 /* 111 * The processor doesn't respond to inquiry cycles while changing the 112 * frequency, so we must disable cache. 113 */ 114 local_irq_disable(); 115 cr0 = read_cr0(); 116 write_cr0(cr0 | X86_CR0_CD); 117 wbinvd(); 118 119 outvalue = (1<<12) | (1<<10) | (1<<9) | (index_to_register[best_i]<<5); 120 121 msrval = POWERNOW_IOPORT + 0x1; 122 wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */ 123 invalue = inl(POWERNOW_IOPORT + 0x8); 124 invalue = invalue & 0x1f; 125 outvalue = outvalue | invalue; 126 outl(outvalue, (POWERNOW_IOPORT + 0x8)); 127 msrval = POWERNOW_IOPORT + 0x0; 128 wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */ 129 130 write_cr0(cr0); 131 local_irq_enable(); 132 } 133 134 /** 135 * powernow_k6_target - set the PowerNow! multiplier 136 * @best_i: clock_ratio[best_i] is the target multiplier 137 * 138 * Tries to change the PowerNow! multiplier 139 */ 140 static int powernow_k6_target(struct cpufreq_policy *policy, 141 unsigned int best_i) 142 { 143 144 if (clock_ratio[best_i].driver_data > max_multiplier) { 145 pr_err("invalid target frequency\n"); 146 return -EINVAL; 147 } 148 149 powernow_k6_set_cpu_multiplier(best_i); 150 151 return 0; 152 } 153 154 static int powernow_k6_cpu_init(struct cpufreq_policy *policy) 155 { 156 struct cpufreq_frequency_table *pos; 157 unsigned int i, f; 158 unsigned khz; 159 160 if (policy->cpu != 0) 161 return -ENODEV; 162 163 max_multiplier = 0; 164 khz = cpu_khz; 165 for (i = 0; i < ARRAY_SIZE(usual_frequency_table); i++) { 166 if (khz >= usual_frequency_table[i].freq - FREQ_RANGE && 167 khz <= usual_frequency_table[i].freq + FREQ_RANGE) { 168 khz = usual_frequency_table[i].freq; 169 max_multiplier = usual_frequency_table[i].mult; 170 break; 171 } 172 } 173 if (param_max_multiplier) { 174 cpufreq_for_each_entry(pos, clock_ratio) 175 if (pos->driver_data == param_max_multiplier) { 176 max_multiplier = param_max_multiplier; 177 goto have_max_multiplier; 178 } 179 pr_err("invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n"); 180 return -EINVAL; 181 } 182 183 if (!max_multiplier) { 184 pr_warn("unknown frequency %u, cannot determine current multiplier\n", 185 khz); 186 pr_warn("use module parameters max_multiplier and bus_frequency\n"); 187 return -EOPNOTSUPP; 188 } 189 190 have_max_multiplier: 191 param_max_multiplier = max_multiplier; 192 193 if (param_busfreq) { 194 if (param_busfreq >= 50000 && param_busfreq <= 150000) { 195 busfreq = param_busfreq / 10; 196 goto have_busfreq; 197 } 198 pr_err("invalid bus_frequency parameter, allowed range 50000 - 150000 kHz\n"); 199 return -EINVAL; 200 } 201 202 busfreq = khz / max_multiplier; 203 have_busfreq: 204 param_busfreq = busfreq * 10; 205 206 /* table init */ 207 cpufreq_for_each_entry(pos, clock_ratio) { 208 f = pos->driver_data; 209 if (f > max_multiplier) 210 pos->frequency = CPUFREQ_ENTRY_INVALID; 211 else 212 pos->frequency = busfreq * f; 213 } 214 215 /* cpuinfo and default policy values */ 216 policy->cpuinfo.transition_latency = 500000; 217 policy->freq_table = clock_ratio; 218 219 return 0; 220 } 221 222 223 static int powernow_k6_cpu_exit(struct cpufreq_policy *policy) 224 { 225 unsigned int i; 226 227 for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) { 228 if (clock_ratio[i].driver_data == max_multiplier) { 229 struct cpufreq_freqs freqs; 230 231 freqs.old = policy->cur; 232 freqs.new = clock_ratio[i].frequency; 233 freqs.flags = 0; 234 235 cpufreq_freq_transition_begin(policy, &freqs); 236 powernow_k6_target(policy, i); 237 cpufreq_freq_transition_end(policy, &freqs, 0); 238 break; 239 } 240 } 241 return 0; 242 } 243 244 static unsigned int powernow_k6_get(unsigned int cpu) 245 { 246 unsigned int ret; 247 ret = (busfreq * powernow_k6_get_cpu_multiplier()); 248 return ret; 249 } 250 251 static struct cpufreq_driver powernow_k6_driver = { 252 .verify = cpufreq_generic_frequency_table_verify, 253 .target_index = powernow_k6_target, 254 .init = powernow_k6_cpu_init, 255 .exit = powernow_k6_cpu_exit, 256 .get = powernow_k6_get, 257 .name = "powernow-k6", 258 .attr = cpufreq_generic_attr, 259 }; 260 261 static const struct x86_cpu_id powernow_k6_ids[] = { 262 { X86_VENDOR_AMD, 5, 12 }, 263 { X86_VENDOR_AMD, 5, 13 }, 264 {} 265 }; 266 MODULE_DEVICE_TABLE(x86cpu, powernow_k6_ids); 267 268 /** 269 * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver 270 * 271 * Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported 272 * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero 273 * on success. 274 */ 275 static int __init powernow_k6_init(void) 276 { 277 if (!x86_match_cpu(powernow_k6_ids)) 278 return -ENODEV; 279 280 if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) { 281 pr_info("PowerNow IOPORT region already used\n"); 282 return -EIO; 283 } 284 285 if (cpufreq_register_driver(&powernow_k6_driver)) { 286 release_region(POWERNOW_IOPORT, 16); 287 return -EINVAL; 288 } 289 290 return 0; 291 } 292 293 294 /** 295 * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support 296 * 297 * Unregisters AMD K6-2+ / K6-3+ PowerNow! support. 298 */ 299 static void __exit powernow_k6_exit(void) 300 { 301 cpufreq_unregister_driver(&powernow_k6_driver); 302 release_region(POWERNOW_IOPORT, 16); 303 } 304 305 306 MODULE_AUTHOR("Arjan van de Ven, Dave Jones, " 307 "Dominik Brodowski <linux@brodo.de>"); 308 MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors."); 309 MODULE_LICENSE("GPL"); 310 311 module_init(powernow_k6_init); 312 module_exit(powernow_k6_exit); 313