// SPDX-License-Identifier: GPL-2.0-only/* * (C) 2002 - 2003  Dominik Brodowski <linux@brodo.de> * *  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/timex.h> #include <asm/msr.h>#include <asm/processor.h>#include <asm/cpu_device_id.h>#include <asm/cpuid/api.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){	struct msr msr; 	rdmsrq(MSR_TMTA_LONGRUN_FLAGS, msr.q);	pr_debug("longrun flags are %x - %x\n", msr.l, msr.h);	if (msr.l & 0x01)		policy->policy = CPUFREQ_POLICY_PERFORMANCE;	else		policy->policy = CPUFREQ_POLICY_POWERSAVE; 	rdmsrq(MSR_TMTA_LONGRUN_CTRL, msr.q);	pr_debug("longrun ctrl is %x - %x\n", msr.l, msr.h);	msr.l &= 0x0000007F;	msr.h &= 0x0000007F; 	if (longrun_high_freq <= longrun_low_freq) {		/* Assume degenerate Longrun table */		policy->min = policy->max = longrun_high_freq;	} else {		policy->min = longrun_low_freq + msr.l *			((longrun_high_freq - longrun_low_freq) / 100);		policy->max = longrun_low_freq + msr.h *			((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){	struct msr msr;	u32 pctg_lo, pctg_hi; 	if (!policy)		return -EINVAL; 	if (longrun_high_freq <= longrun_low_freq) {		/* Assume degenerate Longrun table */		pctg_lo = pctg_hi = 100;	} else {		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 */	rdmsrq(MSR_TMTA_LONGRUN_FLAGS, msr.q);	msr.l &= 0xFFFFFFFE;	switch (policy->policy) {	case CPUFREQ_POLICY_PERFORMANCE:		msr.l |= 0x00000001;		break;	case CPUFREQ_POLICY_POWERSAVE:		break;	}	wrmsrq(MSR_TMTA_LONGRUN_FLAGS, msr.q); 	/* lower and upper boundary */	rdmsrq(MSR_TMTA_LONGRUN_CTRL, msr.q);	msr.l &= 0xFFFFFF80;	msr.h &= 0xFFFFFF80;	msr.l |= pctg_lo;	msr.h |= pctg_hi;	wrmsrq(MSR_TMTA_LONGRUN_CTRL, msr.q); 	return 0;}  /** * longrun_verify_poliy - verifies a new CPUFreq policy * @policy: the policy to verify * * Validates a new CPUFreq policy. This function has to be called with * cpufreq_driver locked. */static int longrun_verify_policy(struct cpufreq_policy_data *policy){	if (!policy)		return -EINVAL; 	policy->cpu = 0;	cpufreq_verify_within_cpu_limits(policy); 	return 0;} static unsigned int longrun_get(unsigned int cpu){	u32 eax, ebx, ecx, edx; 	if (cpu)		return 0; 	cpuid(0x80860007, &eax, &ebx, &ecx, &edx);	pr_debug("cpuid eax is %u\n", eax); 	return eax * 1000;} /** * longrun_determine_freqs - determines the lowest and highest possible core frequency * @low_freq: an int to put the lowest frequency into * @high_freq: an int to put the highest frequency into * * 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 int longrun_determine_freqs(unsigned int *low_freq,						      unsigned int *high_freq){	struct msr msr, save;	u32 eax, ebx, ecx, edx;	u32 try_hi;	struct cpuinfo_x86 *c = &cpu_data(0); 	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 */		rdmsrq(MSR_TMTA_LRTI_READOUT, msr.q);		msr.l = msr.h;		wrmsrq(MSR_TMTA_LRTI_READOUT, msr.q);		rdmsrq(MSR_TMTA_LRTI_VOLT_MHZ, msr.q);		*low_freq = msr.l * 1000; /* to kHz */ 		/* maximum */		msr.l = 0;		wrmsrq(MSR_TMTA_LRTI_READOUT, msr.q);		rdmsrq(MSR_TMTA_LRTI_VOLT_MHZ, msr.q);		*high_freq = msr.l * 1000; /* to kHz */ 		pr_debug("longrun table interface told %u - %u kHz\n",				*low_freq, *high_freq); 		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;	pr_debug("high frequency is %u kHz\n", *high_freq); 	/* get current borders */	rdmsrq(MSR_TMTA_LONGRUN_CTRL, msr.q);	save.l = msr.l & 0x0000007F;	save.h = msr.h & 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);	/* try decreasing in 10% steps, some processors react only	 * on some barrier values */	for (try_hi = 80; try_hi > 0 && ecx > 90; try_hi -= 10) {		/* set to 0 to try_hi perf_pctg */		msr.l &= 0xFFFFFF80;		msr.h &= 0xFFFFFF80;		msr.h |= try_hi;		wrmsrq(MSR_TMTA_LONGRUN_CTRL, msr.q); 		/* read out current core MHz and current perf_pctg */		cpuid(0x80860007, &eax, &ebx, &ecx, &edx); 		/* restore values */		wrmsrq(MSR_TMTA_LONGRUN_CTRL, save.q);	}	pr_debug("percentage is %u %%, freq is %u MHz\n", ecx, eax); 	/* 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) / (100 - ecx);	*low_freq = edx * 1000; /* back to kHz */ 	pr_debug("low frequency is %u kHz\n", *low_freq); 	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;	longrun_get_policy(policy); 	return 0;}  static struct cpufreq_driver longrun_driver = {	.flags		= CPUFREQ_CONST_LOOPS,	.verify		= longrun_verify_policy,	.setpolicy	= longrun_set_policy,	.get		= longrun_get,	.init		= longrun_cpu_init,	.name		= "longrun",}; static const struct x86_cpu_id longrun_ids[] = {	X86_MATCH_VENDOR_FEATURE(TRANSMETA, X86_FEATURE_LONGRUN, NULL),	{}};MODULE_DEVICE_TABLE(x86cpu, longrun_ids); /** * longrun_init - initializes the Transmeta Crusoe LongRun CPUFreq driver * * Initializes the LongRun support. */static int __init longrun_init(void){	if (!x86_match_cpu(longrun_ids))		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 and "		"Efficeon processors.");MODULE_LICENSE("GPL"); module_init(longrun_init);module_exit(longrun_exit);