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