// SPDX-License-Identifier: GPL-2.0-only
/*
 *   (c) 2003-2012 Advanced Micro Devices, Inc.
 *
 *  Maintainer:
 *  Andreas Herrmann <herrmann.der.user@googlemail.com>
 *
 *  Based on the powernow-k7.c module written by Dave Jones.
 *  (C) 2003 Dave Jones on behalf of SuSE Labs
 *  (C) 2004 Dominik Brodowski <linux@brodo.de>
 *  (C) 2004 Pavel Machek <pavel@ucw.cz>
 *  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)
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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 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;

/* 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 __always_unused;

        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);
}

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

/* 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)) {
                pr_err("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) {
                        pr_err("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) {
                pr_err("vid change on fid trans, old 0x%x, new 0x%x\n",
                       savevid, data->currvid);
                return 1;
        }

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

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

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

                if (data->currvid != reqvid) {
                        pr_err("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_MATCH_VENDOR_FAM(AMD, 0xf, NULL),
        {}
};
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)) {
                        pr_info("Processor cpuid %x not supported\n", eax);
                        return;
                }

                eax = cpuid_eax(CPUID_GET_MAX_CAPABILITIES);
                if (eax < CPUID_FREQ_VOLT_CAPABILITIES) {
                        pr_info("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) {
                        pr_info("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) {
                        pr_err(FW_BUG "vid %d invalid : 0x%x\n", j,
                                pst[j].vid);
                        return -EINVAL;
                }
                if (pst[j].vid < data->rvo) {
                        /* vid + rvo >= 0 */
                        pr_err(FW_BUG "0 vid exceeded with pstate %d\n", j);
                        return -ENODEV;
                }
                if (pst[j].vid < maxvid + data->rvo) {
                        /* vid + rvo >= maxvid */
                        pr_err(FW_BUG "maxvid exceeded with pstate %d\n", j);
                        return -ENODEV;
                }
                if (pst[j].fid > MAX_FID) {
                        pr_err(FW_BUG "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 */
                        pr_err(FW_BUG "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) {
                pr_err(FW_BUG "lastfid invalid\n");
                return -EINVAL;
        }
        if (lastfid > LO_FID_TABLE_TOP)
                pr_info(FW_BUG "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) {
                        pr_info("fid 0x%x (%d MHz), vid 0x%x\n",
                                data->powernow_table[j].driver_data & 0xff,
                                data->powernow_table[j].frequency/1000,
                                data->powernow_table[j].driver_data >> 8);
                }
        }
        if (data->batps)
                pr_info("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 */
                pr_warn("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) {
                        pr_err("PST out of sequence\n");
                        return -EINVAL;
                }
        }

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

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

        powernow_table = kzalloc((sizeof(*powernow_table)
                * (data->numps + 1)), GFP_KERNEL);
        if (!powernow_table)
                return -ENOMEM;

        for (j = 0; j < data->numps; j++) {
                int freq;
                powernow_table[j].driver_data = pst[j].fid; /* lower 8 bits */
                powernow_table[j].driver_data |= (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].driver_data = 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(topology_core_cpumask(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) {
                        pr_err(FW_BUG "PSB table is not v1.4\n");
                        return -ENODEV;
                }

                pr_debug("flags: 0x%x\n", psb->flags1);
                if (psb->flags1) {
                        pr_err(FW_BUG "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) {
                        pr_err(FW_BUG "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
         */
        pr_err(FW_BUG "No PSB or ACPI _PSS objects\n");
        pr_err("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 = kzalloc((sizeof(*powernow_table)
                * (data->acpi_data.state_count + 1)), GFP_KERNEL);
        if (!powernow_table)
                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;
        data->powernow_table = powernow_table;

        if (cpumask_first(topology_core_cpumask(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)) {
                pr_err("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->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].driver_data = 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)) {
                        pr_info("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->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 "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,
                struct cpufreq_policy *policy)
{
        u32 fid = 0;
        u32 vid = 0;
        int res;
        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].driver_data & 0xFF;
        vid = (data->powernow_table[index].driver_data & 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);

        cpufreq_freq_transition_begin(policy, &freqs);
        res = transition_fid_vid(data, fid, vid);
        cpufreq_freq_transition_end(policy, &freqs, res);

        return res;
}

struct powernowk8_target_arg {
        struct cpufreq_policy           *pol;
        unsigned                        newstate;
};

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

        if (!data)
                return -EINVAL;

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

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

        pr_debug("targ: cpu %d, %d kHz, min %d, max %d\n",
                pol->cpu, data->powernow_table[newstate].frequency, pol->min,
                pol->max);

        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("error - out of sync, fix 0x%x 0x%x, vid 0x%x 0x%x\n",
                       checkfid, data->currfid,
                       checkvid, data->currvid);
        }

        mutex_lock(&fidvid_mutex);

        powernow_k8_acpi_pst_values(data, newstate);

        ret = transition_frequency_fidvid(data, newstate, pol);

        if (ret) {
                pr_err("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 index)
{
        struct powernowk8_target_arg pta = { .pol = pol, .newstate = index };

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

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

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

        if (pending_bit_stuck()) {

                pr_err("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;
}

#define MISSING_PSS_MSG \
        FW_BUG "No compatible ACPI _PSS objects found.\n" \
        FW_BUG "First, make sure Cool'N'Quiet is enabled in the BIOS.\n" \
        FW_BUG "If that doesn't help, try upgrading your BIOS.\n"

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

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

        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (!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) {
                        pr_err_once(MISSING_PSS_MSG);
                        goto err_out;
                }
                if (pol->cpu != 0) {
                        pr_err(FW_BUG "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, topology_core_cpumask(pol->cpu));
        data->available_cores = pol->cpus;
        pol->freq_table = data->powernow_table;

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

        /* Point all the CPUs in this policy to the same data */
        for_each_cpu(cpu, pol->cpus)
                per_cpu(powernow_data, cpu) = data;

        return 0;

err_out_exit_acpi:
        powernow_k8_cpu_exit_acpi(data);

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

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

        if (!data)
                return -EINVAL;

        powernow_k8_cpu_exit_acpi(data);

        kfree(data->powernow_table);
        kfree(data);
        for_each_cpu(cpu, pol->cpus)
                per_cpu(powernow_data, 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 cpufreq_driver cpufreq_amd64_driver = {
        .flags          = CPUFREQ_ASYNC_NOTIFICATION,
        .verify         = cpufreq_generic_frequency_table_verify,
        .target_index   = powernowk8_target,
        .bios_limit     = acpi_processor_get_bios_limit,
        .init           = powernowk8_cpu_init,
        .exit           = powernowk8_cpu_exit,
        .get            = powernowk8_get,
        .name           = "powernow-k8",
        .attr           = cpufreq_generic_attr,
};

static void __request_acpi_cpufreq(void)
{
        const char drv[] = "acpi-cpufreq";
        const char *cur_drv;

        cur_drv = cpufreq_get_current_driver();
        if (!cur_drv)
                goto request;

        if (strncmp(cur_drv, drv, min_t(size_t, strlen(cur_drv), strlen(drv))))
                pr_warn("WTF driver: %s\n", cur_drv);

        return;

 request:
        pr_warn("This CPU is not supported anymore, using acpi-cpufreq instead.\n");
        request_module(drv);
}

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

        if (boot_cpu_has(X86_FEATURE_HW_PSTATE)) {
                __request_acpi_cpufreq();
                return -ENODEV;
        }

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

        cpus_read_lock();
        for_each_online_cpu(i) {
                smp_call_function_single(i, check_supported_cpu, &ret, 1);
                if (!ret)
                        supported_cpus++;
        }

        if (supported_cpus != num_online_cpus()) {
                cpus_read_unlock();
                return -ENODEV;
        }
        cpus_read_unlock();

        ret = cpufreq_register_driver(&cpufreq_amd64_driver);
        if (ret)
                return ret;

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

        return ret;
}

/* 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 <paul.devriendt@amd.com>");
MODULE_AUTHOR("Mark Langsdorf <mark.langsdorf@amd.com>");
MODULE_DESCRIPTION("AMD Athlon 64 and Opteron processor frequency driver.");
MODULE_LICENSE("GPL");

late_initcall(powernowk8_init);
module_exit(powernowk8_exit);