/* * This file was based upon code in Powertweak Linux (http://powertweak.sf.net) * (C) 2000-2003 Dave Jones, Arjan van de Ven, Janne Pänkälä, * Dominik Brodowski. * * Licensed under the terms of the GNU GPL License version 2. * * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous* */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/cpufreq.h> #include <linux/ioport.h> #include <linux/timex.h> #include <linux/io.h> #include <asm/cpu_device_id.h> #include <asm/msr.h> #define POWERNOW_IOPORT 0xfff0 /* it doesn't matter where, as long as it is unused */ #define PFX "powernow-k6: " static unsigned int busfreq; /* FSB, in 10 kHz */ static unsigned int max_multiplier; static unsigned int param_busfreq = 0; static unsigned int param_max_multiplier = 0; module_param_named(max_multiplier, param_max_multiplier, uint, S_IRUGO); MODULE_PARM_DESC(max_multiplier, "Maximum multiplier (allowed values: 20 30 35 40 45 50 55 60)"); module_param_named(bus_frequency, param_busfreq, uint, S_IRUGO); MODULE_PARM_DESC(bus_frequency, "Bus frequency in kHz"); /* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */ static struct cpufreq_frequency_table clock_ratio[] = { {0, 60, /* 110 -> 6.0x */ 0}, {0, 55, /* 011 -> 5.5x */ 0}, {0, 50, /* 001 -> 5.0x */ 0}, {0, 45, /* 000 -> 4.5x */ 0}, {0, 40, /* 010 -> 4.0x */ 0}, {0, 35, /* 111 -> 3.5x */ 0}, {0, 30, /* 101 -> 3.0x */ 0}, {0, 20, /* 100 -> 2.0x */ 0}, {0, 0, CPUFREQ_TABLE_END} }; static const u8 index_to_register[8] = { 6, 3, 1, 0, 2, 7, 5, 4 }; static const u8 register_to_index[8] = { 3, 2, 4, 1, 7, 6, 0, 5 }; static const struct { unsigned freq; unsigned mult; } usual_frequency_table[] = { { 350000, 35 }, // 100 * 3.5 { 400000, 40 }, // 100 * 4 { 450000, 45 }, // 100 * 4.5 { 475000, 50 }, // 95 * 5 { 500000, 50 }, // 100 * 5 { 506250, 45 }, // 112.5 * 4.5 { 533500, 55 }, // 97 * 5.5 { 550000, 55 }, // 100 * 5.5 { 562500, 50 }, // 112.5 * 5 { 570000, 60 }, // 95 * 6 { 600000, 60 }, // 100 * 6 { 618750, 55 }, // 112.5 * 5.5 { 660000, 55 }, // 120 * 5.5 { 675000, 60 }, // 112.5 * 6 { 720000, 60 }, // 120 * 6 }; #define FREQ_RANGE 3000 /** * powernow_k6_get_cpu_multiplier - returns the current FSB multiplier * * Returns the current setting of the frequency multiplier. Core clock * speed is frequency of the Front-Side Bus multiplied with this value. */ static int powernow_k6_get_cpu_multiplier(void) { unsigned long invalue = 0; u32 msrval; local_irq_disable(); msrval = POWERNOW_IOPORT + 0x1; wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */ invalue = inl(POWERNOW_IOPORT + 0x8); msrval = POWERNOW_IOPORT + 0x0; wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */ local_irq_enable(); return clock_ratio[register_to_index[(invalue >> 5)&7]].driver_data; } static void powernow_k6_set_cpu_multiplier(unsigned int best_i) { unsigned long outvalue, invalue; unsigned long msrval; unsigned long cr0; /* we now need to transform best_i to the BVC format, see AMD#23446 */ /* * The processor doesn't respond to inquiry cycles while changing the * frequency, so we must disable cache. */ local_irq_disable(); cr0 = read_cr0(); write_cr0(cr0 | X86_CR0_CD); wbinvd(); outvalue = (1<<12) | (1<<10) | (1<<9) | (index_to_register[best_i]<<5); msrval = POWERNOW_IOPORT + 0x1; wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */ invalue = inl(POWERNOW_IOPORT + 0x8); invalue = invalue & 0x1f; outvalue = outvalue | invalue; outl(outvalue, (POWERNOW_IOPORT + 0x8)); msrval = POWERNOW_IOPORT + 0x0; wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */ write_cr0(cr0); local_irq_enable(); } /** * powernow_k6_target - set the PowerNow! multiplier * @best_i: clock_ratio[best_i] is the target multiplier * * Tries to change the PowerNow! multiplier */ static int powernow_k6_target(struct cpufreq_policy *policy, unsigned int best_i) { if (clock_ratio[best_i].driver_data > max_multiplier) { printk(KERN_ERR PFX "invalid target frequency\n"); return -EINVAL; } powernow_k6_set_cpu_multiplier(best_i); return 0; } static int powernow_k6_cpu_init(struct cpufreq_policy *policy) { struct cpufreq_frequency_table *pos; unsigned int i, f; unsigned khz; if (policy->cpu != 0) return -ENODEV; max_multiplier = 0; khz = cpu_khz; for (i = 0; i < ARRAY_SIZE(usual_frequency_table); i++) { if (khz >= usual_frequency_table[i].freq - FREQ_RANGE && khz <= usual_frequency_table[i].freq + FREQ_RANGE) { khz = usual_frequency_table[i].freq; max_multiplier = usual_frequency_table[i].mult; break; } } if (param_max_multiplier) { cpufreq_for_each_entry(pos, clock_ratio) if (pos->driver_data == param_max_multiplier) { max_multiplier = param_max_multiplier; goto have_max_multiplier; } printk(KERN_ERR "powernow-k6: invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n"); return -EINVAL; } if (!max_multiplier) { printk(KERN_WARNING "powernow-k6: unknown frequency %u, cannot determine current multiplier\n", khz); printk(KERN_WARNING "powernow-k6: use module parameters max_multiplier and bus_frequency\n"); return -EOPNOTSUPP; } have_max_multiplier: param_max_multiplier = max_multiplier; if (param_busfreq) { if (param_busfreq >= 50000 && param_busfreq <= 150000) { busfreq = param_busfreq / 10; goto have_busfreq; } printk(KERN_ERR "powernow-k6: invalid bus_frequency parameter, allowed range 50000 - 150000 kHz\n"); return -EINVAL; } busfreq = khz / max_multiplier; have_busfreq: param_busfreq = busfreq * 10; /* table init */ cpufreq_for_each_entry(pos, clock_ratio) { f = pos->driver_data; if (f > max_multiplier) pos->frequency = CPUFREQ_ENTRY_INVALID; else pos->frequency = busfreq * f; } /* cpuinfo and default policy values */ policy->cpuinfo.transition_latency = 500000; return cpufreq_table_validate_and_show(policy, clock_ratio); } static int powernow_k6_cpu_exit(struct cpufreq_policy *policy) { unsigned int i; for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) { if (clock_ratio[i].driver_data == max_multiplier) { struct cpufreq_freqs freqs; freqs.old = policy->cur; freqs.new = clock_ratio[i].frequency; freqs.flags = 0; cpufreq_freq_transition_begin(policy, &freqs); powernow_k6_target(policy, i); cpufreq_freq_transition_end(policy, &freqs, 0); break; } } return 0; } static unsigned int powernow_k6_get(unsigned int cpu) { unsigned int ret; ret = (busfreq * powernow_k6_get_cpu_multiplier()); return ret; } static struct cpufreq_driver powernow_k6_driver = { .verify = cpufreq_generic_frequency_table_verify, .target_index = powernow_k6_target, .init = powernow_k6_cpu_init, .exit = powernow_k6_cpu_exit, .get = powernow_k6_get, .name = "powernow-k6", .attr = cpufreq_generic_attr, }; static const struct x86_cpu_id powernow_k6_ids[] = { { X86_VENDOR_AMD, 5, 12 }, { X86_VENDOR_AMD, 5, 13 }, {} }; MODULE_DEVICE_TABLE(x86cpu, powernow_k6_ids); /** * powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver * * Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported * devices, -EINVAL or -ENOMEM on problems during initiatization, and zero * on success. */ static int __init powernow_k6_init(void) { if (!x86_match_cpu(powernow_k6_ids)) return -ENODEV; if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) { printk(KERN_INFO PFX "PowerNow IOPORT region already used.\n"); return -EIO; } if (cpufreq_register_driver(&powernow_k6_driver)) { release_region(POWERNOW_IOPORT, 16); return -EINVAL; } return 0; } /** * powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support * * Unregisters AMD K6-2+ / K6-3+ PowerNow! support. */ static void __exit powernow_k6_exit(void) { cpufreq_unregister_driver(&powernow_k6_driver); release_region(POWERNOW_IOPORT, 16); } MODULE_AUTHOR("Arjan van de Ven, Dave Jones, " "Dominik Brodowski <linux@brodo.de>"); MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors."); MODULE_LICENSE("GPL"); module_init(powernow_k6_init); module_exit(powernow_k6_exit);