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/*

 * Intel SpeedStep SMI driver.

 *

 * (C) 2003  Hiroshi Miura <miura@da-cha.org>

 *

 *  Licensed under the terms of the GNU GPL License version 2.

 *

 */

/*********************************************************************

 *                        SPEEDSTEP - DEFINITIONS                    *

 *********************************************************************/

#include <linuxcomp.h>

#include <linux/kernel.h>

#include <linux/module.h> 

#include <linux/moduleparam.h> 

#include <linux/init.h>

#include <linux/cpufreq.h>

#include <linux/pci.h>

#include <linux/slab.h>

#include <asm/ist.h>

#include "speedstep-lib.h"

#define PFX "speedstep-smi: "

/* speedstep system management interface port/command.

 *

 * These parameters are got from IST-SMI BIOS call.

 * If user gives it, these are used.

 *

 */

static int              smi_port        = 0;

static int              smi_cmd         = 0;

static unsigned int     smi_sig         = 0;

/*

 *   There are only two frequency states for each processor. Values

 * are in kHz for the time being.

 */

static struct cpufreq_frequency_table speedstep_freqs[] = {

        {SPEEDSTEP_HIGH,        0},

        {SPEEDSTEP_LOW,         0},

        {0,                     CPUFREQ_TABLE_END},

};

#define GET_SPEEDSTEP_OWNER 0

#define GET_SPEEDSTEP_STATE 1

#define SET_SPEEDSTEP_STATE 2

#define GET_SPEEDSTEP_FREQS 4

/* DEBUG

 *   Define it if you want verbose debug output, e.g. for bug reporting

 */

//#define SPEEDSTEP_DEBUG

#ifdef SPEEDSTEP_DEBUG

#define dprintk(msg...) printk(msg)

#else

#define dprintk(msg...) do { } while(0)

#endif

/**

 * speedstep_smi_ownership

 */

static int speedstep_smi_ownership (void)

{

        u32 command, result, magic;

        u32 function = GET_SPEEDSTEP_OWNER;

        unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";

        command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);

        magic = virt_to_phys(magic_data);

        __asm__ __volatile__(

                "out %%al, (%%dx)\n"

                : "=D" (result)

                : "a" (command), "b" (function), "c" (0), "d" (smi_port), "D" (0), "S" (magic)

        );

        return result;

}

/**

 * speedstep_smi_get_freqs - get SpeedStep preferred & current freq.

 *

 */

static int speedstep_smi_get_freqs (unsigned int *low, unsigned int *high)

{

        u32 command, result, edi, high_mhz, low_mhz;

        u32 state=0;

        u32 function = GET_SPEEDSTEP_FREQS;

        command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);

        __asm__ __volatile__("movl $0, %%edi\n"

                "out %%al, (%%dx)\n"

                : "=a" (result), "=b" (high_mhz), "=c" (low_mhz), "=d" (state), "=D" (edi)

                : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)

        );

        *high = high_mhz * 1000;

        *low  = low_mhz  * 1000;

        return result;

}

/**

 * speedstep_get_state - set the SpeedStep state

 * @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)

 *

 */

static int speedstep_get_state (void)

{

        u32 function=GET_SPEEDSTEP_STATE;

        u32 result, state, edi, command;

        command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);

        __asm__ __volatile__("movl $0, %%edi\n"

                "out %%al, (%%dx)\n"

                : "=a" (result), "=b" (state), "=D" (edi)

                : "a" (command), "b" (function), "c" (0), "d" (smi_port), "S" (0)

        );

        return state;

}

/**

 * speedstep_set_state - set the SpeedStep state

 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)

 *

 */

static void speedstep_set_state (unsigned int state, unsigned int notify)

{

        unsigned int old_state, result, command, new_state;

        unsigned long flags;

        struct cpufreq_freqs freqs;

        unsigned int function=SET_SPEEDSTEP_STATE;

        if (state > 0x1)

                return;

        old_state = speedstep_get_state();

        freqs.old = speedstep_freqs[old_state].frequency;

        freqs.new = speedstep_freqs[state].frequency;

        freqs.cpu = 0; /* speedstep.c is UP only driver */

        if (old_state == state)

                return;

        if (notify)

                cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

        /* Disable IRQs */

        local_irq_save(flags);

        command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);

        __asm__ __volatile__(

                "movl $0, %%edi\n"

                "out %%al, (%%dx)\n"

                : "=b" (new_state), "=D" (result)

                : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)

        );

        /* enable IRQs */

        local_irq_restore(flags);

        if (new_state == state) {

                dprintk(KERN_INFO "cpufreq: change to %u MHz succeded\n", (freqs.new / 1000));

        } else {

                printk(KERN_ERR "cpufreq: change failed\n");

        }

        if (notify)

                cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

        return;

}

/**

 * speedstep_target - set a new CPUFreq policy

 * @policy: new policy

 * @target_freq: new freq

 * @relation:

 *

 * Sets a new CPUFreq policy/freq.

 */

static int speedstep_target (struct cpufreq_policy *policy,

                        unsigned int target_freq, unsigned int relation)

{

        unsigned int newstate = 0;

        if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0], target_freq, relation, &newstate))

                return -EINVAL;

        speedstep_set_state(newstate, 1);

        return 0;

}

/**

 * speedstep_verify - verifies a new CPUFreq policy

 * @freq: new policy

 *

 * Limit must be within speedstep_low_freq and speedstep_high_freq, with

 * at least one border included.

 */

static int speedstep_verify (struct cpufreq_policy *policy)

{

        return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);

}

static int speedstep_cpu_init(struct cpufreq_policy *policy)

{

        int result;

        unsigned int speed,state;

        /* capability check */

        if (policy->cpu != 0)

                return -ENODEV;

        result = speedstep_smi_ownership();

        if (result)

                dprintk(KERN_INFO "cpufreq: fails an aquiring ownership of a SMI interface.\n");

        /* detect low and high frequency */

        result = speedstep_smi_get_freqs(&speedstep_freqs[SPEEDSTEP_LOW].frequency,

                                &speedstep_freqs[SPEEDSTEP_HIGH].frequency);

        if (result) {

                /* fall back to speedstep_lib.c dection mechanism: try both states out */

                unsigned int speedstep_processor = speedstep_detect_processor();

                dprintk(KERN_INFO PFX "could not detect low and high frequencies by SMI call.\n");

                if (!speedstep_processor)

                        return -ENODEV;

                result = speedstep_get_freqs(speedstep_processor,

                                &speedstep_freqs[SPEEDSTEP_LOW].frequency,

                                &speedstep_freqs[SPEEDSTEP_HIGH].frequency,

                                &speedstep_set_state);

                if (result) {

                        dprintk(KERN_INFO PFX "could not detect two different speeds -- aborting.\n");

                        return result;

                } else

                        dprintk(KERN_INFO PFX "workaround worked.\n");

        }

        /* get current speed setting */

        state = speedstep_get_state();

        speed = speedstep_freqs[state].frequency;

        dprintk(KERN_INFO "cpufreq: currently at %s speed setting - %i MHz\n",

                (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency) ? "low" : "high",

                (speed / 1000));

        /* cpuinfo and default policy values */

        policy->governor = 0; //!!!CPUFREQ_DEFAULT_GOVERNOR;

        policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;

        policy->cur = speed;

        return cpufreq_frequency_table_cpuinfo(policy, &speedstep_freqs[0]);

}

static int speedstep_resume(struct cpufreq_policy *policy)

{

        int result = speedstep_smi_ownership();

        if (result)

                dprintk(KERN_INFO "cpufreq: fails an aquiring ownership of a SMI interface.\n");

        return result;

}

static struct cpufreq_driver speedstep_driver = {

        .name           = "speedstep-smi",

        .verify         = speedstep_verify,

        .target         = speedstep_target,

        .init           = speedstep_cpu_init,

        .resume         = speedstep_resume,

};

/**

 * speedstep_init - initializes the SpeedStep CPUFreq driver

 *

 *   Initializes the SpeedStep support. Returns -ENODEV on unsupported

 * BIOS, -EINVAL on problems during initiatization, and zero on

 * success.

 */

/*static*/ int __init speedstep_smi_init(void)

{

        struct cpuinfo_x86 *c = &new_cpu_data;

        if (c->x86_vendor != X86_VENDOR_INTEL) {

                dprintk (KERN_INFO PFX "No Intel CPU detected.\n");

                return -ENODEV;

        }

        dprintk(KERN_DEBUG PFX "signature:0x%.8lx, command:0x%.8lx, event:0x%.8lx, perf_level:0x%.8lx.\n",

                ist_info.signature, ist_info.command, ist_info.event, ist_info.perf_level);

        /* Error if no IST-SMI BIOS or no PARM

                 sig= 'ISGE' aka 'Intel Speedstep Gate E' */

        if ((ist_info.signature !=  0x47534943) && (

            (smi_port == 0) || (smi_cmd == 0)))

                return -ENODEV;

        if (smi_sig == 1)

                smi_sig = 0x47534943;

        else

                smi_sig = ist_info.signature;

        /* setup smi_port from MODLULE_PARM or BIOS */

        if ((smi_port > 0xff) || (smi_port < 0)) {

                return -EINVAL;

        } else if (smi_port == 0) {

                smi_port = ist_info.command & 0xff;

        }

        if ((smi_cmd > 0xff) || (smi_cmd < 0)) {

                return -EINVAL;

        } else if (smi_cmd == 0) {

                smi_cmd = (ist_info.command >> 16) & 0xff;

        }

        return cpufreq_register_driver(&speedstep_driver);

}

/**

 * speedstep_exit - unregisters SpeedStep support

 *

 *   Unregisters SpeedStep support.

 */

/*static*/ void __exit speedstep_smi_exit(void)

{

        cpufreq_unregister_driver(&speedstep_driver);

}

module_param(smi_port,  int, 0444);

module_param(smi_cmd,   int, 0444);

module_param(smi_sig,  uint, 0444);

MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value -- Intel's default setting is 0xb2");

MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value -- Intel's default setting is 0x82");

MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the SMI interface.");

MODULE_AUTHOR ("Hiroshi Miura");

MODULE_DESCRIPTION ("Speedstep driver for IST applet SMI interface.");

MODULE_LICENSE ("GPL");

module_init(speedstep_smi_init);

module_exit(speedstep_smi_exit);