/* * $Id: longrun.c,v 1.25 2003/02/28 16:03:50 db Exp $ * * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> * * 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/slab.h> #include <linux/cpufreq.h> #include <asm/msr.h> #include <asm/processor.h> #include <asm/timex.h> static struct cpufreq_driver longrun_driver; /** * longrun_{low,high}_freq is needed for the conversion of cpufreq kHz * values into per cent values. In TMTA microcode, the following is valid: * performance_pctg = (current_freq - low_freq)/(high_freq - low_freq) */ static unsigned int longrun_low_freq, longrun_high_freq; /** * longrun_get_policy - get the current LongRun policy * @policy: struct cpufreq_policy where current policy is written into * * Reads the current LongRun policy by access to MSR_TMTA_LONGRUN_FLAGS * and MSR_TMTA_LONGRUN_CTRL */ static void longrun_get_policy(struct cpufreq_policy *policy) { u32 msr_lo, msr_hi; rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi); if (msr_lo & 0x01) policy->policy = CPUFREQ_POLICY_PERFORMANCE; else policy->policy = CPUFREQ_POLICY_POWERSAVE; rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi); msr_lo &= 0x0000007F; msr_hi &= 0x0000007F; policy->min = longrun_low_freq + msr_lo * ((longrun_high_freq - longrun_low_freq) / 100); policy->max = longrun_low_freq + msr_hi * ((longrun_high_freq - longrun_low_freq) / 100); policy->cpu = 0; } /** * longrun_set_policy - sets a new CPUFreq policy * @policy - new policy * * Sets a new CPUFreq policy on LongRun-capable processors. This function * has to be called with cpufreq_driver locked. */ static int longrun_set_policy(struct cpufreq_policy *policy) { u32 msr_lo, msr_hi; u32 pctg_lo, pctg_hi; if (!policy) return -EINVAL; pctg_lo = (policy->min - longrun_low_freq) / ((longrun_high_freq - longrun_low_freq) / 100); pctg_hi = (policy->max - longrun_low_freq) / ((longrun_high_freq - longrun_low_freq) / 100); if (pctg_hi > 100) pctg_hi = 100; if (pctg_lo > pctg_hi) pctg_lo = pctg_hi; /* performance or economy mode */ rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi); msr_lo &= 0xFFFFFFFE; switch (policy->policy) { case CPUFREQ_POLICY_PERFORMANCE: msr_lo |= 0x00000001; break; case CPUFREQ_POLICY_POWERSAVE: break; } wrmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi); /* lower and upper boundary */ rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi); msr_lo &= 0xFFFFFF80; msr_hi &= 0xFFFFFF80; msr_lo |= pctg_lo; msr_hi |= pctg_hi; wrmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi); return 0; } /** * longrun_verify_poliy - verifies a new CPUFreq policy * * Validates a new CPUFreq policy. This function has to be called with * cpufreq_driver locked. */ static int longrun_verify_policy(struct cpufreq_policy *policy) { if (!policy) return -EINVAL; policy->cpu = 0; cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, policy->cpuinfo.max_freq); if (policy->policy == CPUFREQ_POLICY_GOVERNOR) policy->policy = longrun_driver.policy[0].policy; return 0; } /** * longrun_determine_freqs - determines the lowest and highest possible core frequency * * Determines the lowest and highest possible core frequencies on this CPU. * This is necessary to calculate the performance percentage according to * TMTA rules: * performance_pctg = (target_freq - low_freq)/(high_freq - low_freq) */ static unsigned int __init longrun_determine_freqs(unsigned int *low_freq, unsigned int *high_freq) { u32 msr_lo, msr_hi; u32 save_lo, save_hi; u32 eax, ebx, ecx, edx; struct cpuinfo_x86 *c = cpu_data; if (!low_freq || !high_freq) return -EINVAL; if (cpu_has(c, X86_FEATURE_LRTI)) { /* if the LongRun Table Interface is present, the * detection is a bit easier: * For minimum frequency, read out the maximum * level (msr_hi), write that into "currently * selected level", and read out the frequency. * For maximum frequency, read out level zero. */ /* minimum */ rdmsr(MSR_TMTA_LRTI_READOUT, msr_lo, msr_hi); wrmsr(MSR_TMTA_LRTI_READOUT, msr_hi, msr_hi); rdmsr(MSR_TMTA_LRTI_VOLT_MHZ, msr_lo, msr_hi); *low_freq = msr_lo * 1000; /* to kHz */ /* maximum */ wrmsr(MSR_TMTA_LRTI_READOUT, 0, msr_hi); rdmsr(MSR_TMTA_LRTI_VOLT_MHZ, msr_lo, msr_hi); *high_freq = msr_lo * 1000; /* to kHz */ if (*low_freq > *high_freq) *low_freq = *high_freq; return 0; } /* set the upper border to the value determined during TSC init */ *high_freq = (cpu_khz / 1000); *high_freq = *high_freq * 1000; /* get current borders */ rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi); save_lo = msr_lo & 0x0000007F; save_hi = msr_hi & 0x0000007F; /* if current perf_pctg is larger than 90%, we need to decrease the * upper limit to make the calculation more accurate. */ cpuid(0x80860007, &eax, &ebx, &ecx, &edx); if (ecx > 90) { /* set to 0 to 80 perf_pctg */ msr_lo &= 0xFFFFFF80; msr_hi &= 0xFFFFFF80; msr_lo |= 0; msr_hi |= 80; wrmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi); /* read out current core MHz and current perf_pctg */ cpuid(0x80860007, &eax, &ebx, &ecx, &edx); /* restore values */ wrmsr(MSR_TMTA_LONGRUN_CTRL, save_lo, save_hi); } /* performance_pctg = (current_freq - low_freq)/(high_freq - low_freq) * eqals * low_freq * ( 1 - perf_pctg) = (cur_freq - high_freq * perf_pctg) * * high_freq * perf_pctg is stored tempoarily into "ebx". */ ebx = (((cpu_khz / 1000) * ecx) / 100); /* to MHz */ if ((ecx > 95) || (ecx == 0) || (eax < ebx)) return -EIO; edx = (eax - ebx) / (100 - ecx); *low_freq = edx * 1000; /* back to kHz */ if (*low_freq > *high_freq) *low_freq = *high_freq; return 0; } static int longrun_cpu_init(struct cpufreq_policy *policy) { int result = 0; /* capability check */ if (policy->cpu != 0) return -ENODEV; /* detect low and high frequency */ result = longrun_determine_freqs(&longrun_low_freq, &longrun_high_freq); if (result) return result; /* cpuinfo and default policy values */ policy->cpuinfo.min_freq = longrun_low_freq; policy->cpuinfo.max_freq = longrun_high_freq; policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; longrun_get_policy(policy); return 0; } static struct cpufreq_driver longrun_driver = { .verify = longrun_verify_policy, .setpolicy = longrun_set_policy, .init = longrun_cpu_init, .name = "longrun", .owner = THIS_MODULE, }; /** * longrun_init - initializes the Transmeta Crusoe LongRun CPUFreq driver * * Initializes the LongRun support. */ static int __init longrun_init(void) { struct cpuinfo_x86 *c = cpu_data; if (c->x86_vendor != X86_VENDOR_TRANSMETA || !cpu_has(c, X86_FEATURE_LONGRUN)) return -ENODEV; return cpufreq_register_driver(&longrun_driver); } /** * longrun_exit - unregisters LongRun support */ static void __exit longrun_exit(void) { cpufreq_unregister_driver(&longrun_driver); } MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>"); MODULE_DESCRIPTION ("LongRun driver for Transmeta Crusoe processors."); MODULE_LICENSE ("GPL"); module_init(longrun_init); module_exit(longrun_exit);