arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c

/*
 * acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.4 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
 *  Copyright (C) 2006       Denis Sadykov <denis.m.sadykov@intel.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/compiler.h>
#include <linux/sched.h>	/* current */
#include <linux/dmi.h>

#include <linux/acpi.h>
#include <acpi/processor.h>

#include <asm/io.h>
#include <asm/processor.h>
#include <asm/cpufeature.h>
#include <asm/delay.h>
#include <asm/uaccess.h>

#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)

MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
MODULE_DESCRIPTION("ACPI Processor P-States Driver");
MODULE_LICENSE("GPL");


struct acpi_cpufreq_data {
	struct acpi_processor_performance	*acpi_data;
	struct cpufreq_frequency_table		*freq_table;
	unsigned int				resume;
};

static struct acpi_cpufreq_data	*drv_data[NR_CPUS];
static struct acpi_processor_performance	*acpi_perf_data[NR_CPUS];

static struct cpufreq_driver acpi_cpufreq_driver;

static unsigned int acpi_pstate_strict;

static unsigned extract_freq(u32 value, struct acpi_cpufreq_data *data)
{
	struct acpi_processor_performance       *perf;
	int                                     i;

	perf = data->acpi_data;

	for (i = 0; i < perf->state_count; i++) {
		if (value == perf->states[i].status)
			return data->freq_table[i].frequency;
	}
	return 0;
}


static void wrport(u16 port, u8 bit_width, u32 value)
{
	if (bit_width <= 8) {
		outb(value, port);
	} else if (bit_width <= 16) {
		outw(value, port);
	} else if (bit_width <= 32) {
		outl(value, port);
	}
}

static void rdport(u16 port, u8 bit_width, u32 *ret)
{
	*ret = 0;
	if (bit_width <= 8) {
		*ret = inb(port);
	} else if (bit_width <= 16) {
		*ret = inw(port);
	} else if (bit_width <= 32) {
		*ret = inl(port);
	}
}

struct io_addr {
	u16 port;
	u8 bit_width;
};

struct drv_cmd {
	cpumask_t mask;
	struct io_addr addr;
	u32 val;
};

static void do_drv_read(struct drv_cmd *cmd)
{
	rdport(cmd->addr.port, cmd->addr.bit_width, &cmd->val);
	return;
}

static void do_drv_write(struct drv_cmd *cmd)
{
	wrport(cmd->addr.port, cmd->addr.bit_width, cmd->val);
	return;
}

static inline void drv_read(struct drv_cmd *cmd)
{
	cpumask_t	saved_mask = current->cpus_allowed;
	cmd->val = 0;

	set_cpus_allowed(current, cmd->mask);
	do_drv_read(cmd);
	set_cpus_allowed(current, saved_mask);

}

static void drv_write(struct drv_cmd *cmd)
{
	cpumask_t	saved_mask = current->cpus_allowed;
	unsigned int	i;

	for_each_cpu_mask(i, cmd->mask) {
		set_cpus_allowed(current, cpumask_of_cpu(i));
		do_drv_write(cmd);
	}

	set_cpus_allowed(current, saved_mask);
	return;
}

static u32 get_cur_val(cpumask_t mask)
{
	struct acpi_processor_performance	*perf;
	struct drv_cmd				cmd;

	if (unlikely(cpus_empty(mask)))
		return 0;

	perf = drv_data[first_cpu(mask)]->acpi_data;
	cmd.addr.port = perf->control_register.address;
	cmd.addr.bit_width = perf->control_register.bit_width;
	cmd.mask = mask;

	drv_read(&cmd);

	dprintk("get_cur_val = %u\n", cmd.val);

	return cmd.val;
}

static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
{
	struct acpi_cpufreq_data		*data = drv_data[cpu];
	unsigned int				freq;

	dprintk("get_cur_freq_on_cpu (%d)\n", cpu);

	if (unlikely(data == NULL ||
	             data->acpi_data == NULL ||
	             data->freq_table == NULL)) {
		return 0;
	}

	freq = extract_freq(get_cur_val(cpumask_of_cpu(cpu)), data);
	dprintk("cur freq = %u\n", freq);

	return freq;
}

static unsigned int check_freqs(cpumask_t mask, unsigned int freq,
		struct acpi_cpufreq_data *data)
{
	unsigned int	cur_freq;
	unsigned int	i;

	for (i = 0; i < 100; i++) {
		cur_freq = extract_freq(get_cur_val(mask), data);
		if (cur_freq == freq)
			return 1;
		udelay(10);
	}
	return 0;
}

static int acpi_cpufreq_target(struct cpufreq_policy *policy,
				unsigned int target_freq,
				unsigned int relation)
{
	struct acpi_cpufreq_data		*data = drv_data[policy->cpu];
	struct acpi_processor_performance	*perf;
	struct cpufreq_freqs			freqs;
	cpumask_t				online_policy_cpus;
	struct drv_cmd				cmd;
	unsigned int				next_state = 0;
	unsigned int				next_perf_state = 0;
	unsigned int				i;
	int					result = 0;

	dprintk("acpi_cpufreq_target %d (%d)\n", target_freq, policy->cpu);

	if (unlikely(data == NULL ||
	             data->acpi_data == NULL ||
	             data->freq_table == NULL)) {
		return -ENODEV;
	}

	perf = data->acpi_data;
	result = cpufreq_frequency_table_target(policy,
	                                        data->freq_table,
	                                        target_freq,
	                                        relation,
	                                        &next_state);
	if (unlikely(result))
		return -ENODEV;

#ifdef CONFIG_HOTPLUG_CPU
	/* cpufreq holds the hotplug lock, so we are safe from here on */
	cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
#else
	online_policy_cpus = policy->cpus;
#endif

	cmd.val = get_cur_val(online_policy_cpus);
	freqs.old = extract_freq(cmd.val, data);
	freqs.new = data->freq_table[next_state].frequency;
	next_perf_state = data->freq_table[next_state].index;
	if (freqs.new == freqs.old) {
		if (unlikely(data->resume)) {
			dprintk("Called after resume, resetting to P%d\n", next_perf_state);
			data->resume = 0;
		} else {
			dprintk("Already at target state (P%d)\n", next_perf_state);
			return 0;
		}
	}

	cmd.addr.port = perf->control_register.address;
	cmd.addr.bit_width = perf->control_register.bit_width;
	cmd.val = (u32) perf->states[next_perf_state].control;

	cpus_clear(cmd.mask);

	if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
		cmd.mask = online_policy_cpus;
	else
		cpu_set(policy->cpu, cmd.mask);

	for_each_cpu_mask(i, cmd.mask) {
		freqs.cpu = i;
		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	}

	drv_write(&cmd);

	if (acpi_pstate_strict) {
		if (!check_freqs(cmd.mask, freqs.new, data)) {
			dprintk("acpi_cpufreq_target failed (%d)\n",
					policy->cpu);
			return -EAGAIN;
		}
	}

	for_each_cpu_mask(i, cmd.mask) {
		freqs.cpu = i;
		cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	}
	perf->state = next_perf_state;

	return result;
}


static int
acpi_cpufreq_verify (
	struct cpufreq_policy   *policy)
{
	struct acpi_cpufreq_data *data = drv_data[policy->cpu];

	dprintk("acpi_cpufreq_verify\n");

	return cpufreq_frequency_table_verify(policy, data->freq_table);
}


static unsigned long
acpi_cpufreq_guess_freq (
	struct acpi_cpufreq_data	*data,
	unsigned int		cpu)
{
	struct acpi_processor_performance	*perf = data->acpi_data;

	if (cpu_khz) {
		/* search the closest match to cpu_khz */
		unsigned int i;
		unsigned long freq;
		unsigned long freqn = perf->states[0].core_frequency * 1000;

		for (i = 0; i < (perf->state_count - 1); i++) {
			freq = freqn;
			freqn = perf->states[i+1].core_frequency * 1000;
			if ((2 * cpu_khz) > (freqn + freq)) {
				perf->state = i;
				return (freq);
			}
		}
		perf->state = perf->state_count - 1;
		return (freqn);
	} else {
		/* assume CPU is at P0... */
		perf->state = 0;
		return perf->states[0].core_frequency * 1000;
	}
}


/*
 * acpi_cpufreq_early_init - initialize ACPI P-States library
 *
 * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
 * in order to determine correct frequency and voltage pairings. We can
 * do _PDC and _PSD and find out the processor dependency for the
 * actual init that will happen later...
 */
static int acpi_cpufreq_early_init(void)
{
	struct acpi_processor_performance	*data;
	cpumask_t				covered;
	unsigned int				i, j;

	dprintk("acpi_cpufreq_early_init\n");

	for_each_possible_cpu(i) {
		data = kzalloc(sizeof(struct acpi_processor_performance), 
			GFP_KERNEL);
		if (!data) {
			for_each_cpu_mask(j, covered) {
				kfree(acpi_perf_data[j]);
				acpi_perf_data[j] = NULL;
			}
			return (-ENOMEM);
		}
		acpi_perf_data[i] = data;
		cpu_set(i, covered);
	}

	/* Do initialization in ACPI core */
	acpi_processor_preregister_performance(acpi_perf_data);
	return 0;
}

/*
 * Some BIOSes do SW_ANY coordination internally, either set it up in hw
 * or do it in BIOS firmware and won't inform about it to OS. If not
 * detected, this has a side effect of making CPU run at a different speed
 * than OS intended it to run at. Detect it and handle it cleanly.
 */
static int bios_with_sw_any_bug;

static int sw_any_bug_found(struct dmi_system_id *d)
{
	bios_with_sw_any_bug = 1;
	return 0;
}

static struct dmi_system_id sw_any_bug_dmi_table[] = {
	{
		.callback = sw_any_bug_found,
		.ident = "Supermicro Server X6DLP",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
			DMI_MATCH(DMI_BIOS_VERSION, "080010"),
			DMI_MATCH(DMI_PRODUCT_NAME, "X6DLP"),
		},
	},
	{ }
};

static int
acpi_cpufreq_cpu_init (
	struct cpufreq_policy   *policy)
{
	unsigned int			i;
	unsigned int			valid_states = 0;
	unsigned int			cpu = policy->cpu;
	struct acpi_cpufreq_data	*data;
	unsigned int			result = 0;
	struct cpuinfo_x86 		*c = &cpu_data[policy->cpu];
	struct acpi_processor_performance	*perf;

	dprintk("acpi_cpufreq_cpu_init\n");

	if (!acpi_perf_data[cpu])
		return (-ENODEV);

	data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);
	if (!data)
		return (-ENOMEM);

	data->acpi_data = acpi_perf_data[cpu];
	drv_data[cpu] = data;

	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
		acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
	}

	result = acpi_processor_register_performance(data->acpi_data, cpu);
	if (result)
		goto err_free;

	perf = data->acpi_data;
	policy->shared_type = perf->shared_type;
	/*
	 * Will let policy->cpus know about dependency only when software 
	 * coordination is required.
	 */
	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
	    policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
		policy->cpus = perf->shared_cpu_map;
	}

#ifdef CONFIG_SMP
	dmi_check_system(sw_any_bug_dmi_table);
	if (bios_with_sw_any_bug && cpus_weight(policy->cpus) == 1) {
		policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
		policy->cpus = cpu_core_map[cpu];
	}
#endif

	/* capability check */
	if (perf->state_count <= 1) {
		dprintk("No P-States\n");
		result = -ENODEV;
		goto err_unreg;
	}

	if (perf->control_register.space_id != perf->status_register.space_id) {
		result = -ENODEV;
		goto err_unreg;
	}

	switch (perf->control_register.space_id) {
	    case ACPI_ADR_SPACE_SYSTEM_IO:
		dprintk("SYSTEM IO addr space\n");
		break;
	    default:
		dprintk("Unknown addr space %d\n",
				(u32) (perf->control_register.space_id));
		result = -ENODEV;
		goto err_unreg;
	}

	data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (perf->state_count + 1), GFP_KERNEL);
	if (!data->freq_table) {
		result = -ENOMEM;
		goto err_unreg;
	}

	/* detect transition latency */
	policy->cpuinfo.transition_latency = 0;
	for (i=0; i<perf->state_count; i++) {
		if ((perf->states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
			policy->cpuinfo.transition_latency = perf->states[i].transition_latency * 1000;
	}
	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;

	/* The current speed is unknown and not detectable by ACPI...  */
	policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);

	/* table init */
	for (i=0; i<perf->state_count; i++)
	{
		if ( i > 0 && perf->states[i].core_frequency ==
				perf->states[i - 1].core_frequency)
			continue;

		data->freq_table[valid_states].index = i;
		data->freq_table[valid_states].frequency =
			perf->states[i].core_frequency * 1000;
		valid_states++;
	}
	data->freq_table[perf->state_count].frequency = CPUFREQ_TABLE_END;

	result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
	if (result) {
		goto err_freqfree;
	}

	/* notify BIOS that we exist */
	acpi_processor_notify_smm(THIS_MODULE);

	dprintk("CPU%u - ACPI performance management activated.\n", cpu);
	for (i = 0; i < perf->state_count; i++)
		dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
			(i == perf->state?'*':' '), i,
			(u32) perf->states[i].core_frequency,
			(u32) perf->states[i].power,
			(u32) perf->states[i].transition_latency);

	cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
	
	/*
	 * the first call to ->target() should result in us actually
	 * writing something to the appropriate registers.
	 */
	data->resume = 1;
	
	return result;

 err_freqfree:
	kfree(data->freq_table);
 err_unreg:
	acpi_processor_unregister_performance(perf, cpu);
 err_free:
	kfree(data);
	drv_data[cpu] = NULL;

	return (result);
}


static int
acpi_cpufreq_cpu_exit (
	struct cpufreq_policy   *policy)
{
	struct acpi_cpufreq_data *data = drv_data[policy->cpu];


	dprintk("acpi_cpufreq_cpu_exit\n");

	if (data) {
		cpufreq_frequency_table_put_attr(policy->cpu);
		drv_data[policy->cpu] = NULL;
		acpi_processor_unregister_performance(data->acpi_data, policy->cpu);
		kfree(data);
	}

	return (0);
}

static int
acpi_cpufreq_resume (
	struct cpufreq_policy   *policy)
{
	struct acpi_cpufreq_data *data = drv_data[policy->cpu];


	dprintk("acpi_cpufreq_resume\n");

	data->resume = 1;

	return (0);
}


static struct freq_attr* acpi_cpufreq_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static struct cpufreq_driver acpi_cpufreq_driver = {
	.verify	= acpi_cpufreq_verify,
	.target	= acpi_cpufreq_target,
	.get    = get_cur_freq_on_cpu,
	.init	= acpi_cpufreq_cpu_init,
	.exit	= acpi_cpufreq_cpu_exit,
	.resume	= acpi_cpufreq_resume,
	.name	= "acpi-cpufreq",
	.owner	= THIS_MODULE,
	.attr	= acpi_cpufreq_attr,
};


static int __init
acpi_cpufreq_init (void)
{
	dprintk("acpi_cpufreq_init\n");

	acpi_cpufreq_early_init();

	return cpufreq_register_driver(&acpi_cpufreq_driver);
}


static void __exit
acpi_cpufreq_exit (void)
{
	unsigned int	i;
	dprintk("acpi_cpufreq_exit\n");

	cpufreq_unregister_driver(&acpi_cpufreq_driver);

	for_each_possible_cpu(i) {
		kfree(acpi_perf_data[i]);
		acpi_perf_data[i] = NULL;
	}
	return;
}

module_param(acpi_pstate_strict, uint, 0644);
MODULE_PARM_DESC(acpi_pstate_strict, "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");

late_initcall(acpi_cpufreq_init);
module_exit(acpi_cpufreq_exit);

MODULE_ALIAS("acpi");