drivers/cpufreq/powernow-k6.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  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.
  *
  *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #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 */

 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) {
 		pr_err("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;
 			}
 		pr_err("invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n");
 		return -EINVAL;
 	}

 	if (!max_multiplier) {
 		pr_warn("unknown frequency %u, cannot determine current multiplier\n",
 			khz);
 		pr_warn("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;
 		}
 		pr_err("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;
 	policy->freq_table = clock_ratio;

 	return 0;
 }


 static void 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);
 			return;
 		}
 	}
 }

 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_MATCH_VENDOR_FAM_MODEL(AMD, 5, 12, NULL),
 	X86_MATCH_VENDOR_FAM_MODEL(AMD, 5, 13, NULL),
 	{}
 };
 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!")) {
 		pr_info("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);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* 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.
	*
	* BIG FAT DISCLAIMER: Work in progress code. Possibly dangerous
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#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 */

	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) {
	pr_err("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;
	}
	pr_err("invalid max_multiplier parameter, valid parameters 20, 30, 35, 40, 45, 50, 55, 60\n");
	return -EINVAL;
	}

	if (!max_multiplier) {
	pr_warn("unknown frequency %u, cannot determine current multiplier\n",
	khz);
	pr_warn("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;
	}
	pr_err("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;
	policy->freq_table = clock_ratio;

	return 0;
	}


	static void 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);
	return;
	}
	}
	}

	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_MATCH_VENDOR_FAM_MODEL(AMD, 5, 12, NULL),
	X86_MATCH_VENDOR_FAM_MODEL(AMD, 5, 13, NULL),
	{}
	};
	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!")) {
	pr_info("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);