treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / acpi / processor_throttling.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * processor_throttling.c - Throttling submodule of the ACPI processor driver
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
 *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 *                      - Added processor hotplug support
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
#include <asm/io.h>
#include <linux/uaccess.h>

#define PREFIX "ACPI: "

#define ACPI_PROCESSOR_CLASS            "processor"
#define _COMPONENT              ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_throttling");

/* ignore_tpc:
 *  0 -> acpi processor driver doesn't ignore _TPC values
 *  1 -> acpi processor driver ignores _TPC values
 */
static int ignore_tpc;
module_param(ignore_tpc, int, 0644);
MODULE_PARM_DESC(ignore_tpc, "Disable broken BIOS _TPC throttling support");

struct throttling_tstate {
        unsigned int cpu;               /* cpu nr */
        int target_state;               /* target T-state */
};

struct acpi_processor_throttling_arg {
        struct acpi_processor *pr;
        int target_state;
        bool force;
};

#define THROTTLING_PRECHANGE       (1)
#define THROTTLING_POSTCHANGE      (2)

static int acpi_processor_get_throttling(struct acpi_processor *pr);
static int __acpi_processor_set_throttling(struct acpi_processor *pr,
                                           int state, bool force, bool direct);

static int acpi_processor_update_tsd_coord(void)
{
        int count, count_target;
        int retval = 0;
        unsigned int i, j;
        cpumask_var_t covered_cpus;
        struct acpi_processor *pr, *match_pr;
        struct acpi_tsd_package *pdomain, *match_pdomain;
        struct acpi_processor_throttling *pthrottling, *match_pthrottling;

        if (!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))
                return -ENOMEM;

        /*
         * Now that we have _TSD data from all CPUs, lets setup T-state
         * coordination between all CPUs.
         */
        for_each_possible_cpu(i) {
                pr = per_cpu(processors, i);
                if (!pr)
                        continue;

                /* Basic validity check for domain info */
                pthrottling = &(pr->throttling);

                /*
                 * If tsd package for one cpu is invalid, the coordination
                 * among all CPUs is thought as invalid.
                 * Maybe it is ugly.
                 */
                if (!pthrottling->tsd_valid_flag) {
                        retval = -EINVAL;
                        break;
                }
        }
        if (retval)
                goto err_ret;

        for_each_possible_cpu(i) {
                pr = per_cpu(processors, i);
                if (!pr)
                        continue;

                if (cpumask_test_cpu(i, covered_cpus))
                        continue;
                pthrottling = &pr->throttling;

                pdomain = &(pthrottling->domain_info);
                cpumask_set_cpu(i, pthrottling->shared_cpu_map);
                cpumask_set_cpu(i, covered_cpus);
                /*
                 * If the number of processor in the TSD domain is 1, it is
                 * unnecessary to parse the coordination for this CPU.
                 */
                if (pdomain->num_processors <= 1)
                        continue;

                /* Validate the Domain info */
                count_target = pdomain->num_processors;
                count = 1;

                for_each_possible_cpu(j) {
                        if (i == j)
                                continue;

                        match_pr = per_cpu(processors, j);
                        if (!match_pr)
                                continue;

                        match_pthrottling = &(match_pr->throttling);
                        match_pdomain = &(match_pthrottling->domain_info);
                        if (match_pdomain->domain != pdomain->domain)
                                continue;

                        /* Here i and j are in the same domain.
                         * If two TSD packages have the same domain, they
                         * should have the same num_porcessors and
                         * coordination type. Otherwise it will be regarded
                         * as illegal.
                         */
                        if (match_pdomain->num_processors != count_target) {
                                retval = -EINVAL;
                                goto err_ret;
                        }

                        if (pdomain->coord_type != match_pdomain->coord_type) {
                                retval = -EINVAL;
                                goto err_ret;
                        }

                        cpumask_set_cpu(j, covered_cpus);
                        cpumask_set_cpu(j, pthrottling->shared_cpu_map);
                        count++;
                }
                for_each_possible_cpu(j) {
                        if (i == j)
                                continue;

                        match_pr = per_cpu(processors, j);
                        if (!match_pr)
                                continue;

                        match_pthrottling = &(match_pr->throttling);
                        match_pdomain = &(match_pthrottling->domain_info);
                        if (match_pdomain->domain != pdomain->domain)
                                continue;

                        /*
                         * If some CPUS have the same domain, they
                         * will have the same shared_cpu_map.
                         */
                        cpumask_copy(match_pthrottling->shared_cpu_map,
                                     pthrottling->shared_cpu_map);
                }
        }

err_ret:
        free_cpumask_var(covered_cpus);

        for_each_possible_cpu(i) {
                pr = per_cpu(processors, i);
                if (!pr)
                        continue;

                /*
                 * Assume no coordination on any error parsing domain info.
                 * The coordination type will be forced as SW_ALL.
                 */
                if (retval) {
                        pthrottling = &(pr->throttling);
                        cpumask_clear(pthrottling->shared_cpu_map);
                        cpumask_set_cpu(i, pthrottling->shared_cpu_map);
                        pthrottling->shared_type = DOMAIN_COORD_TYPE_SW_ALL;
                }
        }

        return retval;
}

/*
 * Update the T-state coordination after the _TSD
 * data for all cpus is obtained.
 */
void acpi_processor_throttling_init(void)
{
        if (acpi_processor_update_tsd_coord()) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                        "Assume no T-state coordination\n"));
        }

        return;
}

static int acpi_processor_throttling_notifier(unsigned long event, void *data)
{
        struct throttling_tstate *p_tstate = data;
        struct acpi_processor *pr;
        unsigned int cpu ;
        int target_state;
        struct acpi_processor_limit *p_limit;
        struct acpi_processor_throttling *p_throttling;

        cpu = p_tstate->cpu;
        pr = per_cpu(processors, cpu);
        if (!pr) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Invalid pr pointer\n"));
                return 0;
        }
        if (!pr->flags.throttling) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Throttling control is "
                                "unsupported on CPU %d\n", cpu));
                return 0;
        }
        target_state = p_tstate->target_state;
        p_throttling = &(pr->throttling);
        switch (event) {
        case THROTTLING_PRECHANGE:
                /*
                 * Prechange event is used to choose one proper t-state,
                 * which meets the limits of thermal, user and _TPC.
                 */
                p_limit = &pr->limit;
                if (p_limit->thermal.tx > target_state)
                        target_state = p_limit->thermal.tx;
                if (p_limit->user.tx > target_state)
                        target_state = p_limit->user.tx;
                if (pr->throttling_platform_limit > target_state)
                        target_state = pr->throttling_platform_limit;
                if (target_state >= p_throttling->state_count) {
                        printk(KERN_WARNING
                                "Exceed the limit of T-state \n");
                        target_state = p_throttling->state_count - 1;
                }
                p_tstate->target_state = target_state;
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "PreChange Event:"
                                "target T-state of CPU %d is T%d\n",
                                cpu, target_state));
                break;
        case THROTTLING_POSTCHANGE:
                /*
                 * Postchange event is only used to update the
                 * T-state flag of acpi_processor_throttling.
                 */
                p_throttling->state = target_state;
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "PostChange Event:"
                                "CPU %d is switched to T%d\n",
                                cpu, target_state));
                break;
        default:
                printk(KERN_WARNING
                        "Unsupported Throttling notifier event\n");
                break;
        }

        return 0;
}

/*
 * _TPC - Throttling Present Capabilities
 */
static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
{
        acpi_status status = 0;
        unsigned long long tpc = 0;

        if (!pr)
                return -EINVAL;

        if (ignore_tpc)
                goto end;

        status = acpi_evaluate_integer(pr->handle, "_TPC", NULL, &tpc);
        if (ACPI_FAILURE(status)) {
                if (status != AE_NOT_FOUND) {
                        ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TPC"));
                }
                return -ENODEV;
        }

end:
        pr->throttling_platform_limit = (int)tpc;
        return 0;
}

int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
{
        int result = 0;
        int throttling_limit;
        int current_state;
        struct acpi_processor_limit *limit;
        int target_state;

        if (ignore_tpc)
                return 0;

        result = acpi_processor_get_platform_limit(pr);
        if (result) {
                /* Throttling Limit is unsupported */
                return result;
        }

        throttling_limit = pr->throttling_platform_limit;
        if (throttling_limit >= pr->throttling.state_count) {
                /* Uncorrect Throttling Limit */
                return -EINVAL;
        }

        current_state = pr->throttling.state;
        if (current_state > throttling_limit) {
                /*
                 * The current state can meet the requirement of
                 * _TPC limit. But it is reasonable that OSPM changes
                 * t-states from high to low for better performance.
                 * Of course the limit condition of thermal
                 * and user should be considered.
                 */
                limit = &pr->limit;
                target_state = throttling_limit;
                if (limit->thermal.tx > target_state)
                        target_state = limit->thermal.tx;
                if (limit->user.tx > target_state)
                        target_state = limit->user.tx;
        } else if (current_state == throttling_limit) {
                /*
                 * Unnecessary to change the throttling state
                 */
                return 0;
        } else {
                /*
                 * If the current state is lower than the limit of _TPC, it
                 * will be forced to switch to the throttling state defined
                 * by throttling_platfor_limit.
                 * Because the previous state meets with the limit condition
                 * of thermal and user, it is unnecessary to check it again.
                 */
                target_state = throttling_limit;
        }
        return acpi_processor_set_throttling(pr, target_state, false);
}

/*
 * This function is used to reevaluate whether the T-state is valid
 * after one CPU is onlined/offlined.
 * It is noted that it won't reevaluate the following properties for
 * the T-state.
 *      1. Control method.
 *      2. the number of supported T-state
 *      3. TSD domain
 */
void acpi_processor_reevaluate_tstate(struct acpi_processor *pr,
                                        bool is_dead)
{
        int result = 0;

        if (is_dead) {
                /* When one CPU is offline, the T-state throttling
                 * will be invalidated.
                 */
                pr->flags.throttling = 0;
                return;
        }
        /* the following is to recheck whether the T-state is valid for
         * the online CPU
         */
        if (!pr->throttling.state_count) {
                /* If the number of T-state is invalid, it is
                 * invalidated.
                 */
                pr->flags.throttling = 0;
                return;
        }
        pr->flags.throttling = 1;

        /* Disable throttling (if enabled).  We'll let subsequent
         * policy (e.g.thermal) decide to lower performance if it
         * so chooses, but for now we'll crank up the speed.
         */

        result = acpi_processor_get_throttling(pr);
        if (result)
                goto end;

        if (pr->throttling.state) {
                result = acpi_processor_set_throttling(pr, 0, false);
                if (result)
                        goto end;
        }

end:
        if (result)
                pr->flags.throttling = 0;
}
/*
 * _PTC - Processor Throttling Control (and status) register location
 */
static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
{
        int result = 0;
        acpi_status status = 0;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        union acpi_object *ptc = NULL;
        union acpi_object obj = { 0 };
        struct acpi_processor_throttling *throttling;

        status = acpi_evaluate_object(pr->handle, "_PTC", NULL, &buffer);
        if (ACPI_FAILURE(status)) {
                if (status != AE_NOT_FOUND) {
                        ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTC"));
                }
                return -ENODEV;
        }

        ptc = (union acpi_object *)buffer.pointer;
        if (!ptc || (ptc->type != ACPI_TYPE_PACKAGE)
            || (ptc->package.count != 2)) {
                printk(KERN_ERR PREFIX "Invalid _PTC data\n");
                result = -EFAULT;
                goto end;
        }

        /*
         * control_register
         */

        obj = ptc->package.elements[0];

        if ((obj.type != ACPI_TYPE_BUFFER)
            || (obj.buffer.length < sizeof(struct acpi_ptc_register))
            || (obj.buffer.pointer == NULL)) {
                printk(KERN_ERR PREFIX
                       "Invalid _PTC data (control_register)\n");
                result = -EFAULT;
                goto end;
        }
        memcpy(&pr->throttling.control_register, obj.buffer.pointer,
               sizeof(struct acpi_ptc_register));

        /*
         * status_register
         */

        obj = ptc->package.elements[1];

        if ((obj.type != ACPI_TYPE_BUFFER)
            || (obj.buffer.length < sizeof(struct acpi_ptc_register))
            || (obj.buffer.pointer == NULL)) {
                printk(KERN_ERR PREFIX "Invalid _PTC data (status_register)\n");
                result = -EFAULT;
                goto end;
        }

        memcpy(&pr->throttling.status_register, obj.buffer.pointer,
               sizeof(struct acpi_ptc_register));

        throttling = &pr->throttling;

        if ((throttling->control_register.bit_width +
                throttling->control_register.bit_offset) > 32) {
                printk(KERN_ERR PREFIX "Invalid _PTC control register\n");
                result = -EFAULT;
                goto end;
        }

        if ((throttling->status_register.bit_width +
                throttling->status_register.bit_offset) > 32) {
                printk(KERN_ERR PREFIX "Invalid _PTC status register\n");
                result = -EFAULT;
                goto end;
        }

      end:
        kfree(buffer.pointer);

        return result;
}

/*
 * _TSS - Throttling Supported States
 */
static int acpi_processor_get_throttling_states(struct acpi_processor *pr)
{
        int result = 0;
        acpi_status status = AE_OK;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
        struct acpi_buffer state = { 0, NULL };
        union acpi_object *tss = NULL;
        int i;

        status = acpi_evaluate_object(pr->handle, "_TSS", NULL, &buffer);
        if (ACPI_FAILURE(status)) {
                if (status != AE_NOT_FOUND) {
                        ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSS"));
                }
                return -ENODEV;
        }

        tss = buffer.pointer;
        if (!tss || (tss->type != ACPI_TYPE_PACKAGE)) {
                printk(KERN_ERR PREFIX "Invalid _TSS data\n");
                result = -EFAULT;
                goto end;
        }

        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
                          tss->package.count));

        pr->throttling.state_count = tss->package.count;
        pr->throttling.states_tss =
            kmalloc_array(tss->package.count,
                          sizeof(struct acpi_processor_tx_tss),
                          GFP_KERNEL);
        if (!pr->throttling.states_tss) {
                result = -ENOMEM;
                goto end;
        }

        for (i = 0; i < pr->throttling.state_count; i++) {

                struct acpi_processor_tx_tss *tx =
                    (struct acpi_processor_tx_tss *)&(pr->throttling.
                                                      states_tss[i]);

                state.length = sizeof(struct acpi_processor_tx_tss);
                state.pointer = tx;

                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));

                status = acpi_extract_package(&(tss->package.elements[i]),
                                              &format, &state);
                if (ACPI_FAILURE(status)) {
                        ACPI_EXCEPTION((AE_INFO, status, "Invalid _TSS data"));
                        result = -EFAULT;
                        kfree(pr->throttling.states_tss);
                        goto end;
                }

                if (!tx->freqpercentage) {
                        printk(KERN_ERR PREFIX
                               "Invalid _TSS data: freq is zero\n");
                        result = -EFAULT;
                        kfree(pr->throttling.states_tss);
                        goto end;
                }
        }

      end:
        kfree(buffer.pointer);

        return result;
}

/*
 * _TSD - T-State Dependencies
 */
static int acpi_processor_get_tsd(struct acpi_processor *pr)
{
        int result = 0;
        acpi_status status = AE_OK;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
        struct acpi_buffer state = { 0, NULL };
        union acpi_object *tsd = NULL;
        struct acpi_tsd_package *pdomain;
        struct acpi_processor_throttling *pthrottling;

        pthrottling = &pr->throttling;
        pthrottling->tsd_valid_flag = 0;

        status = acpi_evaluate_object(pr->handle, "_TSD", NULL, &buffer);
        if (ACPI_FAILURE(status)) {
                if (status != AE_NOT_FOUND) {
                        ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSD"));
                }
                return -ENODEV;
        }

        tsd = buffer.pointer;
        if (!tsd || (tsd->type != ACPI_TYPE_PACKAGE)) {
                printk(KERN_ERR PREFIX "Invalid _TSD data\n");
                result = -EFAULT;
                goto end;
        }

        if (tsd->package.count != 1) {
                printk(KERN_ERR PREFIX "Invalid _TSD data\n");
                result = -EFAULT;
                goto end;
        }

        pdomain = &(pr->throttling.domain_info);

        state.length = sizeof(struct acpi_tsd_package);
        state.pointer = pdomain;

        status = acpi_extract_package(&(tsd->package.elements[0]),
                                      &format, &state);
        if (ACPI_FAILURE(status)) {
                printk(KERN_ERR PREFIX "Invalid _TSD data\n");
                result = -EFAULT;
                goto end;
        }

        if (pdomain->num_entries != ACPI_TSD_REV0_ENTRIES) {
                printk(KERN_ERR PREFIX "Unknown _TSD:num_entries\n");
                result = -EFAULT;
                goto end;
        }

        if (pdomain->revision != ACPI_TSD_REV0_REVISION) {
                printk(KERN_ERR PREFIX "Unknown _TSD:revision\n");
                result = -EFAULT;
                goto end;
        }

        pthrottling = &pr->throttling;
        pthrottling->tsd_valid_flag = 1;
        pthrottling->shared_type = pdomain->coord_type;
        cpumask_set_cpu(pr->id, pthrottling->shared_cpu_map);
        /*
         * If the coordination type is not defined in ACPI spec,
         * the tsd_valid_flag will be clear and coordination type
         * will be forecd as DOMAIN_COORD_TYPE_SW_ALL.
         */
        if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
                pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
                pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
                pthrottling->tsd_valid_flag = 0;
                pthrottling->shared_type = DOMAIN_COORD_TYPE_SW_ALL;
        }

      end:
        kfree(buffer.pointer);
        return result;
}

/* --------------------------------------------------------------------------
                              Throttling Control
   -------------------------------------------------------------------------- */
static int acpi_processor_get_throttling_fadt(struct acpi_processor *pr)
{
        int state = 0;
        u32 value = 0;
        u32 duty_mask = 0;
        u32 duty_value = 0;

        if (!pr)
                return -EINVAL;

        if (!pr->flags.throttling)
                return -ENODEV;

        /*
         * We don't care about error returns - we just try to mark
         * these reserved so that nobody else is confused into thinking
         * that this region might be unused..
         *
         * (In particular, allocating the IO range for Cardbus)
         */
        request_region(pr->throttling.address, 6, "ACPI CPU throttle");

        pr->throttling.state = 0;

        duty_mask = pr->throttling.state_count - 1;

        duty_mask <<= pr->throttling.duty_offset;

        local_irq_disable();

        value = inl(pr->throttling.address);

        /*
         * Compute the current throttling state when throttling is enabled
         * (bit 4 is on).
         */
        if (value & 0x10) {
                duty_value = value & duty_mask;
                duty_value >>= pr->throttling.duty_offset;

                if (duty_value)
                        state = pr->throttling.state_count - duty_value;
        }

        pr->throttling.state = state;

        local_irq_enable();

        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "Throttling state is T%d (%d%% throttling applied)\n",
                          state, pr->throttling.states[state].performance));

        return 0;
}

#ifdef CONFIG_X86
static int acpi_throttling_rdmsr(u64 *value)
{
        u64 msr_high, msr_low;
        u64 msr = 0;
        int ret = -1;

        if ((this_cpu_read(cpu_info.x86_vendor) != X86_VENDOR_INTEL) ||
                !this_cpu_has(X86_FEATURE_ACPI)) {
                printk(KERN_ERR PREFIX
                        "HARDWARE addr space,NOT supported yet\n");
        } else {
                msr_low = 0;
                msr_high = 0;
                rdmsr_safe(MSR_IA32_THERM_CONTROL,
                        (u32 *)&msr_low , (u32 *) &msr_high);
                msr = (msr_high << 32) | msr_low;
                *value = (u64) msr;
                ret = 0;
        }
        return ret;
}

static int acpi_throttling_wrmsr(u64 value)
{
        int ret = -1;
        u64 msr;

        if ((this_cpu_read(cpu_info.x86_vendor) != X86_VENDOR_INTEL) ||
                !this_cpu_has(X86_FEATURE_ACPI)) {
                printk(KERN_ERR PREFIX
                        "HARDWARE addr space,NOT supported yet\n");
        } else {
                msr = value;
                wrmsr_safe(MSR_IA32_THERM_CONTROL,
                        msr & 0xffffffff, msr >> 32);
                ret = 0;
        }
        return ret;
}
#else
static int acpi_throttling_rdmsr(u64 *value)
{
        printk(KERN_ERR PREFIX
                "HARDWARE addr space,NOT supported yet\n");
        return -1;
}

static int acpi_throttling_wrmsr(u64 value)
{
        printk(KERN_ERR PREFIX
                "HARDWARE addr space,NOT supported yet\n");
        return -1;
}
#endif

static int acpi_read_throttling_status(struct acpi_processor *pr,
                                        u64 *value)
{
        u32 bit_width, bit_offset;
        u32 ptc_value;
        u64 ptc_mask;
        struct acpi_processor_throttling *throttling;
        int ret = -1;

        throttling = &pr->throttling;
        switch (throttling->status_register.space_id) {
        case ACPI_ADR_SPACE_SYSTEM_IO:
                bit_width = throttling->status_register.bit_width;
                bit_offset = throttling->status_register.bit_offset;

                acpi_os_read_port((acpi_io_address) throttling->status_register.
                                  address, &ptc_value,
                                  (u32) (bit_width + bit_offset));
                ptc_mask = (1 << bit_width) - 1;
                *value = (u64) ((ptc_value >> bit_offset) & ptc_mask);
                ret = 0;
                break;
        case ACPI_ADR_SPACE_FIXED_HARDWARE:
                ret = acpi_throttling_rdmsr(value);
                break;
        default:
                printk(KERN_ERR PREFIX "Unknown addr space %d\n",
                       (u32) (throttling->status_register.space_id));
        }
        return ret;
}

static int acpi_write_throttling_state(struct acpi_processor *pr,
                                u64 value)
{
        u32 bit_width, bit_offset;
        u64 ptc_value;
        u64 ptc_mask;
        struct acpi_processor_throttling *throttling;
        int ret = -1;

        throttling = &pr->throttling;
        switch (throttling->control_register.space_id) {
        case ACPI_ADR_SPACE_SYSTEM_IO:
                bit_width = throttling->control_register.bit_width;
                bit_offset = throttling->control_register.bit_offset;
                ptc_mask = (1 << bit_width) - 1;
                ptc_value = value & ptc_mask;

                acpi_os_write_port((acpi_io_address) throttling->
                                        control_register.address,
                                        (u32) (ptc_value << bit_offset),
                                        (u32) (bit_width + bit_offset));
                ret = 0;
                break;
        case ACPI_ADR_SPACE_FIXED_HARDWARE:
                ret = acpi_throttling_wrmsr(value);
                break;
        default:
                printk(KERN_ERR PREFIX "Unknown addr space %d\n",
                       (u32) (throttling->control_register.space_id));
        }
        return ret;
}

static int acpi_get_throttling_state(struct acpi_processor *pr,
                                u64 value)
{
        int i;

        for (i = 0; i < pr->throttling.state_count; i++) {
                struct acpi_processor_tx_tss *tx =
                    (struct acpi_processor_tx_tss *)&(pr->throttling.
                                                      states_tss[i]);
                if (tx->control == value)
                        return i;
        }
        return -1;
}

static int acpi_get_throttling_value(struct acpi_processor *pr,
                        int state, u64 *value)
{
        int ret = -1;

        if (state >= 0 && state <= pr->throttling.state_count) {
                struct acpi_processor_tx_tss *tx =
                    (struct acpi_processor_tx_tss *)&(pr->throttling.
                                                      states_tss[state]);
                *value = tx->control;
                ret = 0;
        }
        return ret;
}

static int acpi_processor_get_throttling_ptc(struct acpi_processor *pr)
{
        int state = 0;
        int ret;
        u64 value;

        if (!pr)
                return -EINVAL;

        if (!pr->flags.throttling)
                return -ENODEV;

        pr->throttling.state = 0;

        value = 0;
        ret = acpi_read_throttling_status(pr, &value);
        if (ret >= 0) {
                state = acpi_get_throttling_state(pr, value);
                if (state == -1) {
                        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                "Invalid throttling state, reset\n"));
                        state = 0;
                        ret = __acpi_processor_set_throttling(pr, state, true,
                                                              true);
                        if (ret)
                                return ret;
                }
                pr->throttling.state = state;
        }

        return 0;
}

static long __acpi_processor_get_throttling(void *data)
{
        struct acpi_processor *pr = data;

        return pr->throttling.acpi_processor_get_throttling(pr);
}

static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct)
{
        if (direct || (is_percpu_thread() && cpu == smp_processor_id()))
                return fn(arg);
        return work_on_cpu(cpu, fn, arg);
}

static int acpi_processor_get_throttling(struct acpi_processor *pr)
{
        if (!pr)
                return -EINVAL;

        if (!pr->flags.throttling)
                return -ENODEV;

        /*
         * This is either called from the CPU hotplug callback of
         * processor_driver or via the ACPI probe function. In the latter
         * case the CPU is not guaranteed to be online. Both call sites are
         * protected against CPU hotplug.
         */
        if (!cpu_online(pr->id))
                return -ENODEV;

        return call_on_cpu(pr->id, __acpi_processor_get_throttling, pr, false);
}

static int acpi_processor_get_fadt_info(struct acpi_processor *pr)
{
        int i, step;

        if (!pr->throttling.address) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n"));
                return -EINVAL;
        } else if (!pr->throttling.duty_width) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling states\n"));
                return -EINVAL;
        }
        /* TBD: Support duty_cycle values that span bit 4. */
        else if ((pr->throttling.duty_offset + pr->throttling.duty_width) > 4) {
                printk(KERN_WARNING PREFIX "duty_cycle spans bit 4\n");
                return -EINVAL;
        }

        pr->throttling.state_count = 1 << acpi_gbl_FADT.duty_width;

        /*
         * Compute state values. Note that throttling displays a linear power
         * performance relationship (at 50% performance the CPU will consume
         * 50% power).  Values are in 1/10th of a percent to preserve accuracy.
         */

        step = (1000 / pr->throttling.state_count);

        for (i = 0; i < pr->throttling.state_count; i++) {
                pr->throttling.states[i].performance = 1000 - step * i;
                pr->throttling.states[i].power = 1000 - step * i;
        }
        return 0;
}

static int acpi_processor_set_throttling_fadt(struct acpi_processor *pr,
                                              int state, bool force)
{
        u32 value = 0;
        u32 duty_mask = 0;
        u32 duty_value = 0;

        if (!pr)
                return -EINVAL;

        if ((state < 0) || (state > (pr->throttling.state_count - 1)))
                return -EINVAL;

        if (!pr->flags.throttling)
                return -ENODEV;

        if (!force && (state == pr->throttling.state))
                return 0;

        if (state < pr->throttling_platform_limit)
                return -EPERM;
        /*
         * Calculate the duty_value and duty_mask.
         */
        if (state) {
                duty_value = pr->throttling.state_count - state;

                duty_value <<= pr->throttling.duty_offset;

                /* Used to clear all duty_value bits */
                duty_mask = pr->throttling.state_count - 1;

                duty_mask <<= acpi_gbl_FADT.duty_offset;
                duty_mask = ~duty_mask;
        }

        local_irq_disable();

        /*
         * Disable throttling by writing a 0 to bit 4.  Note that we must
         * turn it off before you can change the duty_value.
         */
        value = inl(pr->throttling.address);
        if (value & 0x10) {
                value &= 0xFFFFFFEF;
                outl(value, pr->throttling.address);
        }

        /*
         * Write the new duty_value and then enable throttling.  Note
         * that a state value of 0 leaves throttling disabled.
         */
        if (state) {
                value &= duty_mask;
                value |= duty_value;
                outl(value, pr->throttling.address);

                value |= 0x00000010;
                outl(value, pr->throttling.address);
        }

        pr->throttling.state = state;

        local_irq_enable();

        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "Throttling state set to T%d (%d%%)\n", state,
                          (pr->throttling.states[state].performance ? pr->
                           throttling.states[state].performance / 10 : 0)));

        return 0;
}

static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr,
                                             int state, bool force)
{
        int ret;
        u64 value;

        if (!pr)
                return -EINVAL;

        if ((state < 0) || (state > (pr->throttling.state_count - 1)))
                return -EINVAL;

        if (!pr->flags.throttling)
                return -ENODEV;

        if (!force && (state == pr->throttling.state))
                return 0;

        if (state < pr->throttling_platform_limit)
                return -EPERM;

        value = 0;
        ret = acpi_get_throttling_value(pr, state, &value);
        if (ret >= 0) {
                acpi_write_throttling_state(pr, value);
                pr->throttling.state = state;
        }

        return 0;
}

static long acpi_processor_throttling_fn(void *data)
{
        struct acpi_processor_throttling_arg *arg = data;
        struct acpi_processor *pr = arg->pr;

        return pr->throttling.acpi_processor_set_throttling(pr,
                        arg->target_state, arg->force);
}

static int __acpi_processor_set_throttling(struct acpi_processor *pr,
                                           int state, bool force, bool direct)
{
        int ret = 0;
        unsigned int i;
        struct acpi_processor *match_pr;
        struct acpi_processor_throttling *p_throttling;
        struct acpi_processor_throttling_arg arg;
        struct throttling_tstate t_state;

        if (!pr)
                return -EINVAL;

        if (!pr->flags.throttling)
                return -ENODEV;

        if ((state < 0) || (state > (pr->throttling.state_count - 1)))
                return -EINVAL;

        if (cpu_is_offline(pr->id)) {
                /*
                 * the cpu pointed by pr->id is offline. Unnecessary to change
                 * the throttling state any more.
                 */
                return -ENODEV;
        }

        t_state.target_state = state;
        p_throttling = &(pr->throttling);

        /*
         * The throttling notifier will be called for every
         * affected cpu in order to get one proper T-state.
         * The notifier event is THROTTLING_PRECHANGE.
         */
        for_each_cpu_and(i, cpu_online_mask, p_throttling->shared_cpu_map) {
                t_state.cpu = i;
                acpi_processor_throttling_notifier(THROTTLING_PRECHANGE,
                                                        &t_state);
        }
        /*
         * The function of acpi_processor_set_throttling will be called
         * to switch T-state. If the coordination type is SW_ALL or HW_ALL,
         * it is necessary to call it for every affected cpu. Otherwise
         * it can be called only for the cpu pointed by pr.
         */
        if (p_throttling->shared_type == DOMAIN_COORD_TYPE_SW_ANY) {
                arg.pr = pr;
                arg.target_state = state;
                arg.force = force;
                ret = call_on_cpu(pr->id, acpi_processor_throttling_fn, &arg,
                                  direct);
        } else {
                /*
                 * When the T-state coordination is SW_ALL or HW_ALL,
                 * it is necessary to set T-state for every affected
                 * cpus.
                 */
                for_each_cpu_and(i, cpu_online_mask,
                    p_throttling->shared_cpu_map) {
                        match_pr = per_cpu(processors, i);
                        /*
                         * If the pointer is invalid, we will report the
                         * error message and continue.
                         */
                        if (!match_pr) {
                                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                        "Invalid Pointer for CPU %d\n", i));
                                continue;
                        }
                        /*
                         * If the throttling control is unsupported on CPU i,
                         * we will report the error message and continue.
                         */
                        if (!match_pr->flags.throttling) {
                                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                        "Throttling Control is unsupported "
                                        "on CPU %d\n", i));
                                continue;
                        }

                        arg.pr = match_pr;
                        arg.target_state = state;
                        arg.force = force;
                        ret = call_on_cpu(pr->id, acpi_processor_throttling_fn,
                                          &arg, direct);
                }
        }
        /*
         * After the set_throttling is called, the
         * throttling notifier is called for every
         * affected cpu to update the T-states.
         * The notifier event is THROTTLING_POSTCHANGE
         */
        for_each_cpu_and(i, cpu_online_mask, p_throttling->shared_cpu_map) {
                t_state.cpu = i;
                acpi_processor_throttling_notifier(THROTTLING_POSTCHANGE,
                                                        &t_state);
        }

        return ret;
}

int acpi_processor_set_throttling(struct acpi_processor *pr, int state,
                                  bool force)
{
        return __acpi_processor_set_throttling(pr, state, force, false);
}

int acpi_processor_get_throttling_info(struct acpi_processor *pr)
{
        int result = 0;
        struct acpi_processor_throttling *pthrottling;

        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
                          pr->throttling.address,
                          pr->throttling.duty_offset,
                          pr->throttling.duty_width));

        /*
         * Evaluate _PTC, _TSS and _TPC
         * They must all be present or none of them can be used.
         */
        if (acpi_processor_get_throttling_control(pr) ||
                acpi_processor_get_throttling_states(pr) ||
                acpi_processor_get_platform_limit(pr))
        {
                pr->throttling.acpi_processor_get_throttling =
                    &acpi_processor_get_throttling_fadt;
                pr->throttling.acpi_processor_set_throttling =
                    &acpi_processor_set_throttling_fadt;
                if (acpi_processor_get_fadt_info(pr))
                        return 0;
        } else {
                pr->throttling.acpi_processor_get_throttling =
                    &acpi_processor_get_throttling_ptc;
                pr->throttling.acpi_processor_set_throttling =
                    &acpi_processor_set_throttling_ptc;
        }

        /*
         * If TSD package for one CPU can't be parsed successfully, it means
         * that this CPU will have no coordination with other CPUs.
         */
        if (acpi_processor_get_tsd(pr)) {
                pthrottling = &pr->throttling;
                pthrottling->tsd_valid_flag = 0;
                cpumask_set_cpu(pr->id, pthrottling->shared_cpu_map);
                pthrottling->shared_type = DOMAIN_COORD_TYPE_SW_ALL;
        }

        /*
         * PIIX4 Errata: We don't support throttling on the original PIIX4.
         * This shouldn't be an issue as few (if any) mobile systems ever
         * used this part.
         */
        if (errata.piix4.throttle) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Throttling not supported on PIIX4 A- or B-step\n"));
                return 0;
        }

        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
                          pr->throttling.state_count));

        pr->flags.throttling = 1;

        /*
         * Disable throttling (if enabled).  We'll let subsequent policy (e.g.
         * thermal) decide to lower performance if it so chooses, but for now
         * we'll crank up the speed.
         */

        result = acpi_processor_get_throttling(pr);
        if (result)
                goto end;

        if (pr->throttling.state) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Disabling throttling (was T%d)\n",
                                  pr->throttling.state));
                result = acpi_processor_set_throttling(pr, 0, false);
                if (result)
                        goto end;
        }

      end:
        if (result)
                pr->flags.throttling = 0;

        return result;
}