P-state software coordination for acpi-cpufreq

[linux-2.6/mini2440.git] / arch / i386 / kernel / cpu / cpufreq / acpi-cpufreq.c

/*
 * acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
 *
 *  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>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/compiler.h>
#include <linux/sched.h>        /* current */
#include <asm/io.h>
#include <asm/delay.h>
#include <asm/uaccess.h>

#include <linux/acpi.h>
#include <acpi/processor.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 cpufreq_acpi_io {
        struct acpi_processor_performance       *acpi_data;
        struct cpufreq_frequency_table          *freq_table;
        unsigned int                            resume;
};

static struct cpufreq_acpi_io   *acpi_io_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 int
acpi_processor_write_port(
        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);
        } else {
                return -ENODEV;
        }
        return 0;
}

static int
acpi_processor_read_port(
        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);
        } else {
                return -ENODEV;
        }
        return 0;
}

static int
acpi_processor_set_performance (
        struct cpufreq_acpi_io  *data,
        unsigned int            cpu,
        int                     state)
{
        u16                     port = 0;
        u8                      bit_width = 0;
        int                     i = 0;
        int                     ret = 0;
        u32                     value = 0;
        int                     retval;
        struct acpi_processor_performance       *perf;

        dprintk("acpi_processor_set_performance\n");

        retval = 0;
        perf = data->acpi_data; 
        if (state == perf->state) {
                if (unlikely(data->resume)) {
                        dprintk("Called after resume, resetting to P%d\n", state);
                        data->resume = 0;
                } else {
                        dprintk("Already at target state (P%d)\n", state);
                        return (retval);
                }
        }

        dprintk("Transitioning from P%d to P%d\n", perf->state, state);

        /*
         * First we write the target state's 'control' value to the
         * control_register.
         */

        port = perf->control_register.address;
        bit_width = perf->control_register.bit_width;
        value = (u32) perf->states[state].control;

        dprintk("Writing 0x%08x to port 0x%04x\n", value, port);

        ret = acpi_processor_write_port(port, bit_width, value);
        if (ret) {
                dprintk("Invalid port width 0x%04x\n", bit_width);
                return (ret);
        }

        /*
         * Assume the write went through when acpi_pstate_strict is not used.
         * As read status_register is an expensive operation and there 
         * are no specific error cases where an IO port write will fail.
         */
        if (acpi_pstate_strict) {
                /* Then we read the 'status_register' and compare the value 
                 * with the target state's 'status' to make sure the 
                 * transition was successful.
                 * Note that we'll poll for up to 1ms (100 cycles of 10us) 
                 * before giving up.
                 */

                port = perf->status_register.address;
                bit_width = perf->status_register.bit_width;

                dprintk("Looking for 0x%08x from port 0x%04x\n",
                        (u32) perf->states[state].status, port);

                for (i = 0; i < 100; i++) {
                        ret = acpi_processor_read_port(port, bit_width, &value);
                        if (ret) {      
                                dprintk("Invalid port width 0x%04x\n", bit_width);
                                return (ret);
                        }
                        if (value == (u32) perf->states[state].status)
                                break;
                        udelay(10);
                }
        } else {
                i = 0;
                value = (u32) perf->states[state].status;
        }

        if (unlikely(value != (u32) perf->states[state].status)) {
                printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
                retval = -ENODEV;
                return (retval);
        }

        dprintk("Transition successful after %d microseconds\n", i * 10);

        perf->state = state;
        return (retval);
}


static int
acpi_cpufreq_target (
        struct cpufreq_policy   *policy,
        unsigned int target_freq,
        unsigned int relation)
{
        struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
        struct acpi_processor_performance *perf;
        struct cpufreq_freqs freqs;
        cpumask_t online_policy_cpus;
        cpumask_t saved_mask;
        cpumask_t set_mask;
        cpumask_t covered_cpus;
        unsigned int cur_state = 0;
        unsigned int next_state = 0;
        unsigned int result = 0;
        unsigned int j;
        unsigned int tmp;

        dprintk("acpi_cpufreq_setpolicy\n");

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

        perf = data->acpi_data;
        cur_state = perf->state;
        freqs.old = data->freq_table[cur_state].frequency;
        freqs.new = data->freq_table[next_state].frequency;

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

        for_each_cpu_mask(j, online_policy_cpus) {
                freqs.cpu = j;
                cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
        }

        /*
         * We need to call driver->target() on all or any CPU in
         * policy->cpus, depending on policy->shared_type.
         */
        saved_mask = current->cpus_allowed;
        cpus_clear(covered_cpus);
        for_each_cpu_mask(j, online_policy_cpus) {
                /*
                 * Support for SMP systems.
                 * Make sure we are running on CPU that wants to change freq
                 */
                cpus_clear(set_mask);
                if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
                        cpus_or(set_mask, set_mask, online_policy_cpus);
                else
                        cpu_set(j, set_mask);

                set_cpus_allowed(current, set_mask);
                if (unlikely(!cpu_isset(smp_processor_id(), set_mask))) {
                        dprintk("couldn't limit to CPUs in this domain\n");
                        result = -EAGAIN;
                        break;
                }

                result = acpi_processor_set_performance (data, j, next_state);
                if (result) {
                        result = -EAGAIN;
                        break;
                }

                if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
                        break;
 
                cpu_set(j, covered_cpus);
        }

        for_each_cpu_mask(j, online_policy_cpus) {
                freqs.cpu = j;
                cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
        }

        if (unlikely(result)) {
                /*
                 * We have failed halfway through the frequency change.
                 * We have sent callbacks to online_policy_cpus and
                 * acpi_processor_set_performance() has been called on 
                 * coverd_cpus. Best effort undo..
                 */

                if (!cpus_empty(covered_cpus)) {
                        for_each_cpu_mask(j, covered_cpus) {
                                policy->cpu = j;
                                acpi_processor_set_performance (data, 
                                                j, 
                                                cur_state);
                        }
                }

                tmp = freqs.new;
                freqs.new = freqs.old;
                freqs.old = tmp;
                for_each_cpu_mask(j, online_policy_cpus) {
                        freqs.cpu = j;
                        cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
                        cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
                }
        }

        set_cpus_allowed(current, saved_mask);
        return (result);
}


static int
acpi_cpufreq_verify (
        struct cpufreq_policy   *policy)
{
        unsigned int result = 0;
        struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];

        dprintk("acpi_cpufreq_verify\n");

        result = cpufreq_frequency_table_verify(policy, 
                        data->freq_table);

        return (result);
}


static unsigned long
acpi_cpufreq_guess_freq (
        struct cpufreq_acpi_io  *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_acpi(void)
{
        struct acpi_processor_performance       *data;
        unsigned int                            i, j;

        dprintk("acpi_cpufreq_early_init\n");

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

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

static int
acpi_cpufreq_cpu_init (
        struct cpufreq_policy   *policy)
{
        unsigned int            i;
        unsigned int            cpu = policy->cpu;
        struct cpufreq_acpi_io  *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 cpufreq_acpi_io), GFP_KERNEL);
        if (!data)
                return (-ENOMEM);

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

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

        if (result)
                goto err_free;

        perf = data->acpi_data;
        policy->cpus = perf->shared_cpu_map;
        policy->shared_type = perf->shared_type;

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

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

        if ((perf->control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
            (perf->status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
                dprintk("Unsupported address space [%d, %d]\n",
                        (u32) (perf->control_register.space_id),
                        (u32) (perf->status_register.space_id));
                result = -ENODEV;
                goto err_unreg;
        }

        /* alloc freq_table */
        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++)
        {
                data->freq_table[i].index = i;
                if (i<perf->state_count)
                        data->freq_table[i].frequency = perf->states[i].core_frequency * 1000;
                else
                        data->freq_table[i].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);

        printk(KERN_INFO "acpi-cpufreq: 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);
        acpi_io_data[cpu] = NULL;

        return (result);
}


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


        dprintk("acpi_cpufreq_cpu_exit\n");

        if (data) {
                cpufreq_frequency_table_put_attr(policy->cpu);
                acpi_io_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 cpufreq_acpi_io *data = acpi_io_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,
        .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)
{
        int                     result = 0;

        dprintk("acpi_cpufreq_init\n");

        result = acpi_cpufreq_early_init_acpi();

        if (!result)
                result = cpufreq_register_driver(&acpi_cpufreq_driver);
        
        return (result);
}


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

        cpufreq_unregister_driver(&acpi_cpufreq_driver);

        for_each_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");