powernow-k8.c

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/*
 *   (c) 2003-2012 Advanced Micro Devices, Inc.
 *  Your use of this code is subject to the terms and conditions of the
 *  GNU general public license version 2. See "COPYING" or
 *  http://www.gnu.org/licenses/gpl.html
 *
 *  Maintainer:
 *  Andreas Herrmann <[email protected]>
 *
 *  Based on the powernow-k7.c module written by Dave Jones.
 *  (C) 2003 Dave Jones on behalf of SuSE Labs
 *  (C) 2004 Dominik Brodowski <[email protected]>
 *  (C) 2004 Pavel Machek <[email protected]>
 *  Licensed under the terms of the GNU GPL License version 2.
 *  Based upon datasheets & sample CPUs kindly provided by AMD.
 *
 *  Valuable input gratefully received from Dave Jones, Pavel Machek,
 *  Dominik Brodowski, Jacob Shin, and others.
 *  Originally developed by Paul Devriendt.
 *
 *  Processor information obtained from Chapter 9 (Power and Thermal
 *  Management) of the "BIOS and Kernel Developer's Guide (BKDG) for
 *  the AMD Athlon 64 and AMD Opteron Processors" and section "2.x
 *  Power Management" in BKDGs for newer AMD CPU families.
 *
 *  Tables for specific CPUs can be inferred from AMD's processor
 *  power and thermal data sheets, (e.g. 30417.pdf, 30430.pdf, 43375.pdf)
 */

#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/cpumask.h>
#include <linux/io.h>
#include <linux/delay.h>

#include <asm/msr.h>
#include <asm/cpu_device_id.h>

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

#define PFX "powernow-k8: "
#define VERSION "version 2.20.00"
#include "powernow-k8.h"

/* serialize freq changes  */
static DEFINE_MUTEX(fidvid_mutex);

static DEFINE_PER_CPU(struct powernow_k8_data *, powernow_data);

static struct cpufreq_driver cpufreq_amd64_driver;

#ifndef CONFIG_SMP
static inline const struct cpumask *cpu_core_mask(int cpu)
{
    return cpumask_of(0);
}
#endif

/* Return a frequency in MHz, given an input fid */
static u32 find_freq_from_fid(u32 fid)
{
    return 800 + (fid * 100);
}

/* Return a frequency in KHz, given an input fid */
static u32 find_khz_freq_from_fid(u32 fid)
{
    return 1000 * find_freq_from_fid(fid);
}

/* Return the vco fid for an input fid
 *
 * Each "low" fid has corresponding "high" fid, and you can get to "low" fids
 * only from corresponding high fids. This returns "high" fid corresponding to
 * "low" one.
 */
static u32 convert_fid_to_vco_fid(u32 fid)
{
    if (fid < HI_FID_TABLE_BOTTOM)
        return 8 + (2 * fid);
    else
        return fid;
}

/*
 * Return 1 if the pending bit is set. Unless we just instructed the processor
 * to transition to a new state, seeing this bit set is really bad news.
 */
static int pending_bit_stuck(void)
{
    u32 lo, hi;

    rdmsr(MSR_FIDVID_STATUS, lo, hi);
    return lo & MSR_S_LO_CHANGE_PENDING ? 1 : 0;
}

/*
 * Update the global current fid / vid values from the status msr.
 * Returns 1 on error.
 */
static int query_current_values_with_pending_wait(struct powernow_k8_data *data)
{
    u32 lo, hi;
    u32 i = 0;

    do {
        if (i++ > 10000) {
            pr_debug("detected change pending stuck\n");
            return 1;
        }
        rdmsr(MSR_FIDVID_STATUS, lo, hi);
    } while (lo & MSR_S_LO_CHANGE_PENDING);

    data->currvid = hi & MSR_S_HI_CURRENT_VID;
    data->currfid = lo & MSR_S_LO_CURRENT_FID;

    return 0;
}

/* the isochronous relief time */
static void count_off_irt(struct powernow_k8_data *data)
{
    udelay((1 << data->irt) * 10);
    return;
}

/* the voltage stabilization time */
static void count_off_vst(struct powernow_k8_data *data)
{
    udelay(data->vstable * VST_UNITS_20US);
    return;
}

/* need to init the control msr to a safe value (for each cpu) */
static void fidvid_msr_init(void)
{
    u32 lo, hi;
    u8 fid, vid;

    rdmsr(MSR_FIDVID_STATUS, lo, hi);
    vid = hi & MSR_S_HI_CURRENT_VID;
    fid = lo & MSR_S_LO_CURRENT_FID;
    lo = fid | (vid << MSR_C_LO_VID_SHIFT);
    hi = MSR_C_HI_STP_GNT_BENIGN;
    pr_debug("cpu%d, init lo 0x%x, hi 0x%x\n", smp_processor_id(), lo, hi);
    wrmsr(MSR_FIDVID_CTL, lo, hi);
}

/* write the new fid value along with the other control fields to the msr */
static int write_new_fid(struct powernow_k8_data *data, u32 fid)
{
    u32 lo;
    u32 savevid = data->currvid;
    u32 i = 0;

    if ((fid & INVALID_FID_MASK) || (data->currvid & INVALID_VID_MASK)) {
        printk(KERN_ERR PFX "internal error - overflow on fid write\n");
        return 1;
    }

    lo = fid;
    lo |= (data->currvid << MSR_C_LO_VID_SHIFT);
    lo |= MSR_C_LO_INIT_FID_VID;

    pr_debug("writing fid 0x%x, lo 0x%x, hi 0x%x\n",
        fid, lo, data->plllock * PLL_LOCK_CONVERSION);

    do {
        wrmsr(MSR_FIDVID_CTL, lo, data->plllock * PLL_LOCK_CONVERSION);
        if (i++ > 100) {
            printk(KERN_ERR PFX
                "Hardware error - pending bit very stuck - "
                "no further pstate changes possible\n");
            return 1;
        }
    } while (query_current_values_with_pending_wait(data));

    count_off_irt(data);

    if (savevid != data->currvid) {
        printk(KERN_ERR PFX
            "vid change on fid trans, old 0x%x, new 0x%x\n",
            savevid, data->currvid);
        return 1;
    }

    if (fid != data->currfid) {
        printk(KERN_ERR PFX
            "fid trans failed, fid 0x%x, curr 0x%x\n", fid,
            data->currfid);
        return 1;
    }

    return 0;
}

/* Write a new vid to the hardware */
static int write_new_vid(struct powernow_k8_data *data, u32 vid)
{
    u32 lo;
    u32 savefid = data->currfid;
    int i = 0;

    if ((data->currfid & INVALID_FID_MASK) || (vid & INVALID_VID_MASK)) {
        printk(KERN_ERR PFX "internal error - overflow on vid write\n");
        return 1;
    }

    lo = data->currfid;
    lo |= (vid << MSR_C_LO_VID_SHIFT);
    lo |= MSR_C_LO_INIT_FID_VID;

    pr_debug("writing vid 0x%x, lo 0x%x, hi 0x%x\n",
        vid, lo, STOP_GRANT_5NS);

    do {
        wrmsr(MSR_FIDVID_CTL, lo, STOP_GRANT_5NS);
        if (i++ > 100) {
            printk(KERN_ERR PFX "internal error - pending bit "
                    "very stuck - no further pstate "
                    "changes possible\n");
            return 1;
        }
    } while (query_current_values_with_pending_wait(data));

    if (savefid != data->currfid) {
        printk(KERN_ERR PFX "fid changed on vid trans, old "
            "0x%x new 0x%x\n",
               savefid, data->currfid);
        return 1;
    }

    if (vid != data->currvid) {
        printk(KERN_ERR PFX "vid trans failed, vid 0x%x, "
                "curr 0x%x\n",
                vid, data->currvid);
        return 1;
    }

    return 0;
}

/*
 * Reduce the vid by the max of step or reqvid.
 * Decreasing vid codes represent increasing voltages:
 * vid of 0 is 1.550V, vid of 0x1e is 0.800V, vid of VID_OFF is off.
 */
static int decrease_vid_code_by_step(struct powernow_k8_data *data,
        u32 reqvid, u32 step)
{
    if ((data->currvid - reqvid) > step)
        reqvid = data->currvid - step;

    if (write_new_vid(data, reqvid))
        return 1;

    count_off_vst(data);

    return 0;
}

/* Change Opteron/Athlon64 fid and vid, by the 3 phases. */
static int transition_fid_vid(struct powernow_k8_data *data,
        u32 reqfid, u32 reqvid)
{
    if (core_voltage_pre_transition(data, reqvid, reqfid))
        return 1;

    if (core_frequency_transition(data, reqfid))
        return 1;

    if (core_voltage_post_transition(data, reqvid))
        return 1;

    if (query_current_values_with_pending_wait(data))
        return 1;

    if ((reqfid != data->currfid) || (reqvid != data->currvid)) {
        printk(KERN_ERR PFX "failed (cpu%d): req 0x%x 0x%x, "
                "curr 0x%x 0x%x\n",
                smp_processor_id(),
                reqfid, reqvid, data->currfid, data->currvid);
        return 1;
    }

    pr_debug("transitioned (cpu%d): new fid 0x%x, vid 0x%x\n",
        smp_processor_id(), data->currfid, data->currvid);

    return 0;
}

/* Phase 1 - core voltage transition ... setup voltage */
static int core_voltage_pre_transition(struct powernow_k8_data *data,
        u32 reqvid, u32 reqfid)
{
    u32 rvosteps = data->rvo;
    u32 savefid = data->currfid;
    u32 maxvid, lo, rvomult = 1;

    pr_debug("ph1 (cpu%d): start, currfid 0x%x, currvid 0x%x, "
        "reqvid 0x%x, rvo 0x%x\n",
        smp_processor_id(),
        data->currfid, data->currvid, reqvid, data->rvo);

    if ((savefid < LO_FID_TABLE_TOP) && (reqfid < LO_FID_TABLE_TOP))
        rvomult = 2;
    rvosteps *= rvomult;
    rdmsr(MSR_FIDVID_STATUS, lo, maxvid);
    maxvid = 0x1f & (maxvid >> 16);
    pr_debug("ph1 maxvid=0x%x\n", maxvid);
    if (reqvid < maxvid) /* lower numbers are higher voltages */
        reqvid = maxvid;

    while (data->currvid > reqvid) {
        pr_debug("ph1: curr 0x%x, req vid 0x%x\n",
            data->currvid, reqvid);
        if (decrease_vid_code_by_step(data, reqvid, data->vidmvs))
            return 1;
    }

    while ((rvosteps > 0) &&
            ((rvomult * data->rvo + data->currvid) > reqvid)) {
        if (data->currvid == maxvid) {
            rvosteps = 0;
        } else {
            pr_debug("ph1: changing vid for rvo, req 0x%x\n",
                data->currvid - 1);
            if (decrease_vid_code_by_step(data, data->currvid-1, 1))
                return 1;
            rvosteps--;
        }
    }

    if (query_current_values_with_pending_wait(data))
        return 1;

    if (savefid != data->currfid) {
        printk(KERN_ERR PFX "ph1 err, currfid changed 0x%x\n",
                data->currfid);
        return 1;
    }

    pr_debug("ph1 complete, currfid 0x%x, currvid 0x%x\n",
        data->currfid, data->currvid);

    return 0;
}

/* Phase 2 - core frequency transition */
static int core_frequency_transition(struct powernow_k8_data *data, u32 reqfid)
{
    u32 vcoreqfid, vcocurrfid, vcofiddiff;
    u32 fid_interval, savevid = data->currvid;

    if (data->currfid == reqfid) {
        printk(KERN_ERR PFX "ph2 null fid transition 0x%x\n",
                data->currfid);
        return 0;
    }

    pr_debug("ph2 (cpu%d): starting, currfid 0x%x, currvid 0x%x, "
        "reqfid 0x%x\n",
        smp_processor_id(),
        data->currfid, data->currvid, reqfid);

    vcoreqfid = convert_fid_to_vco_fid(reqfid);
    vcocurrfid = convert_fid_to_vco_fid(data->currfid);
    vcofiddiff = vcocurrfid > vcoreqfid ? vcocurrfid - vcoreqfid
        : vcoreqfid - vcocurrfid;

    if ((reqfid <= LO_FID_TABLE_TOP) && (data->currfid <= LO_FID_TABLE_TOP))
        vcofiddiff = 0;

    while (vcofiddiff > 2) {
        (data->currfid & 1) ? (fid_interval = 1) : (fid_interval = 2);

        if (reqfid > data->currfid) {
            if (data->currfid > LO_FID_TABLE_TOP) {
                if (write_new_fid(data,
                        data->currfid + fid_interval))
                    return 1;
            } else {
                if (write_new_fid
                    (data,
                     2 + convert_fid_to_vco_fid(data->currfid)))
                    return 1;
            }
        } else {
            if (write_new_fid(data, data->currfid - fid_interval))
                return 1;
        }

        vcocurrfid = convert_fid_to_vco_fid(data->currfid);
        vcofiddiff = vcocurrfid > vcoreqfid ? vcocurrfid - vcoreqfid
            : vcoreqfid - vcocurrfid;
    }

    if (write_new_fid(data, reqfid))
        return 1;

    if (query_current_values_with_pending_wait(data))
        return 1;

    if (data->currfid != reqfid) {
        printk(KERN_ERR PFX
            "ph2: mismatch, failed fid transition, "
            "curr 0x%x, req 0x%x\n",
            data->currfid, reqfid);
        return 1;
    }

    if (savevid != data->currvid) {
        printk(KERN_ERR PFX "ph2: vid changed, save 0x%x, curr 0x%x\n",
            savevid, data->currvid);
        return 1;
    }

    pr_debug("ph2 complete, currfid 0x%x, currvid 0x%x\n",
        data->currfid, data->currvid);

    return 0;
}

/* Phase 3 - core voltage transition flow ... jump to the final vid. */
static int core_voltage_post_transition(struct powernow_k8_data *data,
        u32 reqvid)
{
    u32 savefid = data->currfid;
    u32 savereqvid = reqvid;

    pr_debug("ph3 (cpu%d): starting, currfid 0x%x, currvid 0x%x\n",
        smp_processor_id(),
        data->currfid, data->currvid);

    if (reqvid != data->currvid) {
        if (write_new_vid(data, reqvid))
            return 1;

        if (savefid != data->currfid) {
            printk(KERN_ERR PFX
                   "ph3: bad fid change, save 0x%x, curr 0x%x\n",
                   savefid, data->currfid);
            return 1;
        }

        if (data->currvid != reqvid) {
            printk(KERN_ERR PFX
                   "ph3: failed vid transition\n, "
                   "req 0x%x, curr 0x%x",
                   reqvid, data->currvid);
            return 1;
        }
    }

    if (query_current_values_with_pending_wait(data))
        return 1;

    if (savereqvid != data->currvid) {
        pr_debug("ph3 failed, currvid 0x%x\n", data->currvid);
        return 1;
    }

    if (savefid != data->currfid) {
        pr_debug("ph3 failed, currfid changed 0x%x\n",
            data->currfid);
        return 1;
    }

    pr_debug("ph3 complete, currfid 0x%x, currvid 0x%x\n",
        data->currfid, data->currvid);

    return 0;
}

static const struct x86_cpu_id powernow_k8_ids[] = {
    /* IO based frequency switching */
    { X86_VENDOR_AMD, 0xf },
    {}
};
MODULE_DEVICE_TABLE(x86cpu, powernow_k8_ids);

static void check_supported_cpu(void *_rc)
{
    u32 eax, ebx, ecx, edx;
    int *rc = _rc;

    *rc = -ENODEV;

    eax = cpuid_eax(CPUID_PROCESSOR_SIGNATURE);

    if ((eax & CPUID_XFAM) == CPUID_XFAM_K8) {
        if (((eax & CPUID_USE_XFAM_XMOD) != CPUID_USE_XFAM_XMOD) ||
            ((eax & CPUID_XMOD) > CPUID_XMOD_REV_MASK)) {
            printk(KERN_INFO PFX
                "Processor cpuid %x not supported\n", eax);
            return;
        }

        eax = cpuid_eax(CPUID_GET_MAX_CAPABILITIES);
        if (eax < CPUID_FREQ_VOLT_CAPABILITIES) {
            printk(KERN_INFO PFX
                   "No frequency change capabilities detected\n");
            return;
        }

        cpuid(CPUID_FREQ_VOLT_CAPABILITIES, &eax, &ebx, &ecx, &edx);
        if ((edx & P_STATE_TRANSITION_CAPABLE)
            != P_STATE_TRANSITION_CAPABLE) {
            printk(KERN_INFO PFX
                "Power state transitions not supported\n");
            return;
        }
        *rc = 0;
    }
}

static int check_pst_table(struct powernow_k8_data *data, struct pst_s *pst,
        u8 maxvid)
{
    unsigned int j;
    u8 lastfid = 0xff;

    for (j = 0; j < data->numps; j++) {
        if (pst[j].vid > LEAST_VID) {
            printk(KERN_ERR FW_BUG PFX "vid %d invalid : 0x%x\n",
                   j, pst[j].vid);
            return -EINVAL;
        }
        if (pst[j].vid < data->rvo) {
            /* vid + rvo >= 0 */
            printk(KERN_ERR FW_BUG PFX "0 vid exceeded with pstate"
                   " %d\n", j);
            return -ENODEV;
        }
        if (pst[j].vid < maxvid + data->rvo) {
            /* vid + rvo >= maxvid */
            printk(KERN_ERR FW_BUG PFX "maxvid exceeded with pstate"
                   " %d\n", j);
            return -ENODEV;
        }
        if (pst[j].fid > MAX_FID) {
            printk(KERN_ERR FW_BUG PFX "maxfid exceeded with pstate"
                   " %d\n", j);
            return -ENODEV;
        }
        if (j && (pst[j].fid < HI_FID_TABLE_BOTTOM)) {
            /* Only first fid is allowed to be in "low" range */
            printk(KERN_ERR FW_BUG PFX "two low fids - %d : "
                   "0x%x\n", j, pst[j].fid);
            return -EINVAL;
        }
        if (pst[j].fid < lastfid)
            lastfid = pst[j].fid;
    }
    if (lastfid & 1) {
        printk(KERN_ERR FW_BUG PFX "lastfid invalid\n");
        return -EINVAL;
    }
    if (lastfid > LO_FID_TABLE_TOP)
        printk(KERN_INFO FW_BUG PFX
            "first fid not from lo freq table\n");

    return 0;
}

static void invalidate_entry(struct cpufreq_frequency_table *powernow_table,
        unsigned int entry)
{
    powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
}

static void print_basics(struct powernow_k8_data *data)
{
    int j;
    for (j = 0; j < data->numps; j++) {
        if (data->powernow_table[j].frequency !=
                CPUFREQ_ENTRY_INVALID) {
                printk(KERN_INFO PFX
                    "fid 0x%x (%d MHz), vid 0x%x\n",
                    data->powernow_table[j].index & 0xff,
                    data->powernow_table[j].frequency/1000,
                    data->powernow_table[j].index >> 8);
        }
    }
    if (data->batps)
        printk(KERN_INFO PFX "Only %d pstates on battery\n",
                data->batps);
}

static int fill_powernow_table(struct powernow_k8_data *data,
        struct pst_s *pst, u8 maxvid)
{
    struct cpufreq_frequency_table *powernow_table;
    unsigned int j;

    if (data->batps) {
        /* use ACPI support to get full speed on mains power */
        printk(KERN_WARNING PFX
            "Only %d pstates usable (use ACPI driver for full "
            "range\n", data->batps);
        data->numps = data->batps;
    }

    for (j = 1; j < data->numps; j++) {
        if (pst[j-1].fid >= pst[j].fid) {
            printk(KERN_ERR PFX "PST out of sequence\n");
            return -EINVAL;
        }
    }

    if (data->numps < 2) {
        printk(KERN_ERR PFX "no p states to transition\n");
        return -ENODEV;
    }

    if (check_pst_table(data, pst, maxvid))
        return -EINVAL;

    powernow_table = kmalloc((sizeof(struct cpufreq_frequency_table)
        * (data->numps + 1)), GFP_KERNEL);
    if (!powernow_table) {
        printk(KERN_ERR PFX "powernow_table memory alloc failure\n");
        return -ENOMEM;
    }

    for (j = 0; j < data->numps; j++) {
        int freq;
        powernow_table[j].index = pst[j].fid; /* lower 8 bits */
        powernow_table[j].index |= (pst[j].vid << 8); /* upper 8 bits */
        freq = find_khz_freq_from_fid(pst[j].fid);
        powernow_table[j].frequency = freq;
    }
    powernow_table[data->numps].frequency = CPUFREQ_TABLE_END;
    powernow_table[data->numps].index = 0;

    if (query_current_values_with_pending_wait(data)) {
        kfree(powernow_table);
        return -EIO;
    }

    pr_debug("cfid 0x%x, cvid 0x%x\n", data->currfid, data->currvid);
    data->powernow_table = powernow_table;
    if (cpumask_first(cpu_core_mask(data->cpu)) == data->cpu)
        print_basics(data);

    for (j = 0; j < data->numps; j++)
        if ((pst[j].fid == data->currfid) &&
            (pst[j].vid == data->currvid))
            return 0;

    pr_debug("currfid/vid do not match PST, ignoring\n");
    return 0;
}

/* Find and validate the PSB/PST table in BIOS. */
static int find_psb_table(struct powernow_k8_data *data)
{
    struct psb_s *psb;
    unsigned int i;
    u32 mvs;
    u8 maxvid;
    u32 cpst = 0;
    u32 thiscpuid;

    for (i = 0xc0000; i < 0xffff0; i += 0x10) {
        /* Scan BIOS looking for the signature. */
        /* It can not be at ffff0 - it is too big. */

        psb = phys_to_virt(i);
        if (memcmp(psb, PSB_ID_STRING, PSB_ID_STRING_LEN) != 0)
            continue;

        pr_debug("found PSB header at 0x%p\n", psb);

        pr_debug("table vers: 0x%x\n", psb->tableversion);
        if (psb->tableversion != PSB_VERSION_1_4) {
            printk(KERN_ERR FW_BUG PFX "PSB table is not v1.4\n");
            return -ENODEV;
        }

        pr_debug("flags: 0x%x\n", psb->flags1);
        if (psb->flags1) {
            printk(KERN_ERR FW_BUG PFX "unknown flags\n");
            return -ENODEV;
        }

        data->vstable = psb->vstable;
        pr_debug("voltage stabilization time: %d(*20us)\n",
                data->vstable);

        pr_debug("flags2: 0x%x\n", psb->flags2);
        data->rvo = psb->flags2 & 3;
        data->irt = ((psb->flags2) >> 2) & 3;
        mvs = ((psb->flags2) >> 4) & 3;
        data->vidmvs = 1 << mvs;
        data->batps = ((psb->flags2) >> 6) & 3;

        pr_debug("ramp voltage offset: %d\n", data->rvo);
        pr_debug("isochronous relief time: %d\n", data->irt);
        pr_debug("maximum voltage step: %d - 0x%x\n", mvs, data->vidmvs);

        pr_debug("numpst: 0x%x\n", psb->num_tables);
        cpst = psb->num_tables;
        if ((psb->cpuid == 0x00000fc0) ||
            (psb->cpuid == 0x00000fe0)) {
            thiscpuid = cpuid_eax(CPUID_PROCESSOR_SIGNATURE);
            if ((thiscpuid == 0x00000fc0) ||
                (thiscpuid == 0x00000fe0))
                cpst = 1;
        }
        if (cpst != 1) {
            printk(KERN_ERR FW_BUG PFX "numpst must be 1\n");
            return -ENODEV;
        }

        data->plllock = psb->plllocktime;
        pr_debug("plllocktime: 0x%x (units 1us)\n", psb->plllocktime);
        pr_debug("maxfid: 0x%x\n", psb->maxfid);
        pr_debug("maxvid: 0x%x\n", psb->maxvid);
        maxvid = psb->maxvid;

        data->numps = psb->numps;
        pr_debug("numpstates: 0x%x\n", data->numps);
        return fill_powernow_table(data,
                (struct pst_s *)(psb+1), maxvid);
    }
    /*
     * If you see this message, complain to BIOS manufacturer. If
     * he tells you "we do not support Linux" or some similar
     * nonsense, remember that Windows 2000 uses the same legacy
     * mechanism that the old Linux PSB driver uses. Tell them it
     * is broken with Windows 2000.
     *
     * The reference to the AMD documentation is chapter 9 in the
     * BIOS and Kernel Developer's Guide, which is available on
     * www.amd.com
     */
    printk(KERN_ERR FW_BUG PFX "No PSB or ACPI _PSS objects\n");
    printk(KERN_ERR PFX "Make sure that your BIOS is up to date"
        " and Cool'N'Quiet support is enabled in BIOS setup\n");
    return -ENODEV;
}

static void powernow_k8_acpi_pst_values(struct powernow_k8_data *data,
        unsigned int index)
{
    u64 control;

    if (!data->acpi_data.state_count)
        return;

    control = data->acpi_data.states[index].control;
    data->irt = (control >> IRT_SHIFT) & IRT_MASK;
    data->rvo = (control >> RVO_SHIFT) & RVO_MASK;
    data->exttype = (control >> EXT_TYPE_SHIFT) & EXT_TYPE_MASK;
    data->plllock = (control >> PLL_L_SHIFT) & PLL_L_MASK;
    data->vidmvs = 1 << ((control >> MVS_SHIFT) & MVS_MASK);
    data->vstable = (control >> VST_SHIFT) & VST_MASK;
}

static int powernow_k8_cpu_init_acpi(struct powernow_k8_data *data)
{
    struct cpufreq_frequency_table *powernow_table;
    int ret_val = -ENODEV;
    u64 control, status;

    if (acpi_processor_register_performance(&data->acpi_data, data->cpu)) {
        pr_debug("register performance failed: bad ACPI data\n");
        return -EIO;
    }

    /* verify the data contained in the ACPI structures */
    if (data->acpi_data.state_count <= 1) {
        pr_debug("No ACPI P-States\n");
        goto err_out;
    }

    control = data->acpi_data.control_register.space_id;
    status = data->acpi_data.status_register.space_id;

    if ((control != ACPI_ADR_SPACE_FIXED_HARDWARE) ||
        (status != ACPI_ADR_SPACE_FIXED_HARDWARE)) {
        pr_debug("Invalid control/status registers (%llx - %llx)\n",
            control, status);
        goto err_out;
    }

    /* fill in data->powernow_table */
    powernow_table = kmalloc((sizeof(struct cpufreq_frequency_table)
        * (data->acpi_data.state_count + 1)), GFP_KERNEL);
    if (!powernow_table) {
        pr_debug("powernow_table memory alloc failure\n");
        goto err_out;
    }

    /* fill in data */
    data->numps = data->acpi_data.state_count;
    powernow_k8_acpi_pst_values(data, 0);

    ret_val = fill_powernow_table_fidvid(data, powernow_table);
    if (ret_val)
        goto err_out_mem;

    powernow_table[data->acpi_data.state_count].frequency =
        CPUFREQ_TABLE_END;
    powernow_table[data->acpi_data.state_count].index = 0;
    data->powernow_table = powernow_table;

    if (cpumask_first(cpu_core_mask(data->cpu)) == data->cpu)
        print_basics(data);

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

    if (!zalloc_cpumask_var(&data->acpi_data.shared_cpu_map, GFP_KERNEL)) {
        printk(KERN_ERR PFX
                "unable to alloc powernow_k8_data cpumask\n");
        ret_val = -ENOMEM;
        goto err_out_mem;
    }

    return 0;

err_out_mem:
    kfree(powernow_table);

err_out:
    acpi_processor_unregister_performance(&data->acpi_data, data->cpu);

    /* data->acpi_data.state_count informs us at ->exit()
     * whether ACPI was used */
    data->acpi_data.state_count = 0;

    return ret_val;
}

static int fill_powernow_table_fidvid(struct powernow_k8_data *data,
        struct cpufreq_frequency_table *powernow_table)
{
    int i;

    for (i = 0; i < data->acpi_data.state_count; i++) {
        u32 fid;
        u32 vid;
        u32 freq, index;
        u64 status, control;

        if (data->exttype) {
            status =  data->acpi_data.states[i].status;
            fid = status & EXT_FID_MASK;
            vid = (status >> VID_SHIFT) & EXT_VID_MASK;
        } else {
            control =  data->acpi_data.states[i].control;
            fid = control & FID_MASK;
            vid = (control >> VID_SHIFT) & VID_MASK;
        }

        pr_debug("   %d : fid 0x%x, vid 0x%x\n", i, fid, vid);

        index = fid | (vid<<8);
        powernow_table[i].index = index;

        freq = find_khz_freq_from_fid(fid);
        powernow_table[i].frequency = freq;

        /* verify frequency is OK */
        if ((freq > (MAX_FREQ * 1000)) || (freq < (MIN_FREQ * 1000))) {
            pr_debug("invalid freq %u kHz, ignoring\n", freq);
            invalidate_entry(powernow_table, i);
            continue;
        }

        /* verify voltage is OK -
         * BIOSs are using "off" to indicate invalid */
        if (vid == VID_OFF) {
            pr_debug("invalid vid %u, ignoring\n", vid);
            invalidate_entry(powernow_table, i);
            continue;
        }

        if (freq != (data->acpi_data.states[i].core_frequency * 1000)) {
            printk(KERN_INFO PFX "invalid freq entries "
                "%u kHz vs. %u kHz\n", freq,
                (unsigned int)
                (data->acpi_data.states[i].core_frequency
                 * 1000));
            invalidate_entry(powernow_table, i);
            continue;
        }
    }
    return 0;
}

static void powernow_k8_cpu_exit_acpi(struct powernow_k8_data *data)
{
    if (data->acpi_data.state_count)
        acpi_processor_unregister_performance(&data->acpi_data,
                data->cpu);
    free_cpumask_var(data->acpi_data.shared_cpu_map);
}

static int get_transition_latency(struct powernow_k8_data *data)
{
    int max_latency = 0;
    int i;
    for (i = 0; i < data->acpi_data.state_count; i++) {
        int cur_latency = data->acpi_data.states[i].transition_latency
            + data->acpi_data.states[i].bus_master_latency;
        if (cur_latency > max_latency)
            max_latency = cur_latency;
    }
    if (max_latency == 0) {
        pr_err(FW_WARN PFX "Invalid zero transition latency\n");
        max_latency = 1;
    }
    /* value in usecs, needs to be in nanoseconds */
    return 1000 * max_latency;
}

/* Take a frequency, and issue the fid/vid transition command */
static int transition_frequency_fidvid(struct powernow_k8_data *data,
        unsigned int index)
{
    u32 fid = 0;
    u32 vid = 0;
    int res, i;
    struct cpufreq_freqs freqs;

    pr_debug("cpu %d transition to index %u\n", smp_processor_id(), index);

    /* fid/vid correctness check for k8 */
    /* fid are the lower 8 bits of the index we stored into
     * the cpufreq frequency table in find_psb_table, vid
     * are the upper 8 bits.
     */
    fid = data->powernow_table[index].index & 0xFF;
    vid = (data->powernow_table[index].index & 0xFF00) >> 8;

    pr_debug("table matched fid 0x%x, giving vid 0x%x\n", fid, vid);

    if (query_current_values_with_pending_wait(data))
        return 1;

    if ((data->currvid == vid) && (data->currfid == fid)) {
        pr_debug("target matches current values (fid 0x%x, vid 0x%x)\n",
            fid, vid);
        return 0;
    }

    pr_debug("cpu %d, changing to fid 0x%x, vid 0x%x\n",
        smp_processor_id(), fid, vid);
    freqs.old = find_khz_freq_from_fid(data->currfid);
    freqs.new = find_khz_freq_from_fid(fid);

    for_each_cpu(i, data->available_cores) {
        freqs.cpu = i;
        cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
    }

    res = transition_fid_vid(data, fid, vid);
    if (res)
        return res;

    freqs.new = find_khz_freq_from_fid(data->currfid);

    for_each_cpu(i, data->available_cores) {
        freqs.cpu = i;
        cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
    }
    return res;
}

struct powernowk8_target_arg {
    struct cpufreq_policy       *pol;
    unsigned            targfreq;
    unsigned            relation;
};

static long powernowk8_target_fn(void *arg)
{
    struct powernowk8_target_arg *pta = arg;
    struct cpufreq_policy *pol = pta->pol;
    unsigned targfreq = pta->targfreq;
    unsigned relation = pta->relation;
    struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu);
    u32 checkfid;
    u32 checkvid;
    unsigned int newstate;
    int ret;

    if (!data)
        return -EINVAL;

    checkfid = data->currfid;
    checkvid = data->currvid;

    if (pending_bit_stuck()) {
        printk(KERN_ERR PFX "failing targ, change pending bit set\n");
        return -EIO;
    }

    pr_debug("targ: cpu %d, %d kHz, min %d, max %d, relation %d\n",
        pol->cpu, targfreq, pol->min, pol->max, relation);

    if (query_current_values_with_pending_wait(data))
        return -EIO;

    pr_debug("targ: curr fid 0x%x, vid 0x%x\n",
         data->currfid, data->currvid);

    if ((checkvid != data->currvid) ||
        (checkfid != data->currfid)) {
        pr_info(PFX
               "error - out of sync, fix 0x%x 0x%x, vid 0x%x 0x%x\n",
               checkfid, data->currfid,
               checkvid, data->currvid);
    }

    if (cpufreq_frequency_table_target(pol, data->powernow_table,
                targfreq, relation, &newstate))
        return -EIO;

    mutex_lock(&fidvid_mutex);

    powernow_k8_acpi_pst_values(data, newstate);

    ret = transition_frequency_fidvid(data, newstate);

    if (ret) {
        printk(KERN_ERR PFX "transition frequency failed\n");
        mutex_unlock(&fidvid_mutex);
        return 1;
    }
    mutex_unlock(&fidvid_mutex);

    pol->cur = find_khz_freq_from_fid(data->currfid);

    return 0;
}

/* Driver entry point to switch to the target frequency */
static int powernowk8_target(struct cpufreq_policy *pol,
        unsigned targfreq, unsigned relation)
{
    struct powernowk8_target_arg pta = { .pol = pol, .targfreq = targfreq,
                         .relation = relation };

    return work_on_cpu(pol->cpu, powernowk8_target_fn, &pta);
}

/* Driver entry point to verify the policy and range of frequencies */
static int powernowk8_verify(struct cpufreq_policy *pol)
{
    struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu);

    if (!data)
        return -EINVAL;

    return cpufreq_frequency_table_verify(pol, data->powernow_table);
}

struct init_on_cpu {
    struct powernow_k8_data *data;
    int rc;
};

static void __cpuinit powernowk8_cpu_init_on_cpu(void *_init_on_cpu)
{
    struct init_on_cpu *init_on_cpu = _init_on_cpu;

    if (pending_bit_stuck()) {
        printk(KERN_ERR PFX "failing init, change pending bit set\n");
        init_on_cpu->rc = -ENODEV;
        return;
    }

    if (query_current_values_with_pending_wait(init_on_cpu->data)) {
        init_on_cpu->rc = -ENODEV;
        return;
    }

    fidvid_msr_init();

    init_on_cpu->rc = 0;
}

static const char missing_pss_msg[] =
    KERN_ERR
    FW_BUG PFX "No compatible ACPI _PSS objects found.\n"
    FW_BUG PFX "First, make sure Cool'N'Quiet is enabled in the BIOS.\n"
    FW_BUG PFX "If that doesn't help, try upgrading your BIOS.\n";

/* per CPU init entry point to the driver */
static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)
{
    struct powernow_k8_data *data;
    struct init_on_cpu init_on_cpu;
    int rc;

    if (!cpu_online(pol->cpu))
        return -ENODEV;

    smp_call_function_single(pol->cpu, check_supported_cpu, &rc, 1);
    if (rc)
        return -ENODEV;

    data = kzalloc(sizeof(struct powernow_k8_data), GFP_KERNEL);
    if (!data) {
        printk(KERN_ERR PFX "unable to alloc powernow_k8_data");
        return -ENOMEM;
    }

    data->cpu = pol->cpu;

    if (powernow_k8_cpu_init_acpi(data)) {
        /*
         * Use the PSB BIOS structure. This is only available on
         * an UP version, and is deprecated by AMD.
         */
        if (num_online_cpus() != 1) {
            printk_once(missing_pss_msg);
            goto err_out;
        }
        if (pol->cpu != 0) {
            printk(KERN_ERR FW_BUG PFX "No ACPI _PSS objects for "
                   "CPU other than CPU0. Complain to your BIOS "
                   "vendor.\n");
            goto err_out;
        }
        rc = find_psb_table(data);
        if (rc)
            goto err_out;

        /* Take a crude guess here.
         * That guess was in microseconds, so multiply with 1000 */
        pol->cpuinfo.transition_latency = (
             ((data->rvo + 8) * data->vstable * VST_UNITS_20US) +
             ((1 << data->irt) * 30)) * 1000;
    } else /* ACPI _PSS objects available */
        pol->cpuinfo.transition_latency = get_transition_latency(data);

    /* only run on specific CPU from here on */
    init_on_cpu.data = data;
    smp_call_function_single(data->cpu, powernowk8_cpu_init_on_cpu,
                 &init_on_cpu, 1);
    rc = init_on_cpu.rc;
    if (rc != 0)
        goto err_out_exit_acpi;

    cpumask_copy(pol->cpus, cpu_core_mask(pol->cpu));
    data->available_cores = pol->cpus;

    pol->cur = find_khz_freq_from_fid(data->currfid);
    pr_debug("policy current frequency %d kHz\n", pol->cur);

    /* min/max the cpu is capable of */
    if (cpufreq_frequency_table_cpuinfo(pol, data->powernow_table)) {
        printk(KERN_ERR FW_BUG PFX "invalid powernow_table\n");
        powernow_k8_cpu_exit_acpi(data);
        kfree(data->powernow_table);
        kfree(data);
        return -EINVAL;
    }

    cpufreq_frequency_table_get_attr(data->powernow_table, pol->cpu);

    pr_debug("cpu_init done, current fid 0x%x, vid 0x%x\n",
         data->currfid, data->currvid);

    per_cpu(powernow_data, pol->cpu) = data;

    return 0;

err_out_exit_acpi:
    powernow_k8_cpu_exit_acpi(data);

err_out:
    kfree(data);
    return -ENODEV;
}

static int __devexit powernowk8_cpu_exit(struct cpufreq_policy *pol)
{
    struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu);

    if (!data)
        return -EINVAL;

    powernow_k8_cpu_exit_acpi(data);

    cpufreq_frequency_table_put_attr(pol->cpu);

    kfree(data->powernow_table);
    kfree(data);
    per_cpu(powernow_data, pol->cpu) = NULL;

    return 0;
}

static void query_values_on_cpu(void *_err)
{
    int *err = _err;
    struct powernow_k8_data *data = __this_cpu_read(powernow_data);

    *err = query_current_values_with_pending_wait(data);
}

static unsigned int powernowk8_get(unsigned int cpu)
{
    struct powernow_k8_data *data = per_cpu(powernow_data, cpu);
    unsigned int khz = 0;
    int err;

    if (!data)
        return 0;

    smp_call_function_single(cpu, query_values_on_cpu, &err, true);
    if (err)
        goto out;

    khz = find_khz_freq_from_fid(data->currfid);


out:
    return khz;
}

static struct freq_attr *powernow_k8_attr[] = {
    &cpufreq_freq_attr_scaling_available_freqs,
    NULL,
};

static struct cpufreq_driver cpufreq_amd64_driver = {
    .verify     = powernowk8_verify,
    .target     = powernowk8_target,
    .bios_limit = acpi_processor_get_bios_limit,
    .init       = powernowk8_cpu_init,
    .exit       = __devexit_p(powernowk8_cpu_exit),
    .get        = powernowk8_get,
    .name       = "powernow-k8",
    .owner      = THIS_MODULE,
    .attr       = powernow_k8_attr,
};

/* driver entry point for init */
static int __cpuinit powernowk8_init(void)
{
    unsigned int i, supported_cpus = 0;
    int rv;

    if (static_cpu_has(X86_FEATURE_HW_PSTATE)) {
        pr_warn(PFX "this CPU is not supported anymore, using acpi-cpufreq instead.\n");
        request_module("acpi-cpufreq");
        return -ENODEV;
    }

    if (!x86_match_cpu(powernow_k8_ids))
        return -ENODEV;

    for_each_online_cpu(i) {
        int rc;
        smp_call_function_single(i, check_supported_cpu, &rc, 1);
        if (rc == 0)
            supported_cpus++;
    }

    if (supported_cpus != num_online_cpus())
        return -ENODEV;

    rv = cpufreq_register_driver(&cpufreq_amd64_driver);

    if (!rv)
        pr_info(PFX "Found %d %s (%d cpu cores) (" VERSION ")\n",
            num_online_nodes(), boot_cpu_data.x86_model_id,
            supported_cpus);

    return rv;
}

/* driver entry point for term */
static void __exit powernowk8_exit(void)
{
    pr_debug("exit\n");

    cpufreq_unregister_driver(&cpufreq_amd64_driver);
}

MODULE_AUTHOR("Paul Devriendt <[email protected]> and "
        "Mark Langsdorf <[email protected]>");
MODULE_DESCRIPTION("AMD Athlon 64 and Opteron processor frequency driver.");
MODULE_LICENSE("GPL");

late_initcall(powernowk8_init);
module_exit(powernowk8_exit);