ips: use interruptible waits in ips-monitor

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / platform / x86 / intel_ips.c

/*
 * Copyright (c) 2009-2010 Intel Corporation
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * The full GNU General Public License is included in this distribution in
 * the file called "COPYING".
 *
 * Authors:
 *      Jesse Barnes <jbarnes@virtuousgeek.org>
 */

/*
 * Some Intel Ibex Peak based platforms support so-called "intelligent
 * power sharing", which allows the CPU and GPU to cooperate to maximize
 * performance within a given TDP (thermal design point).  This driver
 * performs the coordination between the CPU and GPU, monitors thermal and
 * power statistics in the platform, and initializes power monitoring
 * hardware.  It also provides a few tunables to control behavior.  Its
 * primary purpose is to safely allow CPU and GPU turbo modes to be enabled
 * by tracking power and thermal budget; secondarily it can boost turbo
 * performance by allocating more power or thermal budget to the CPU or GPU
 * based on available headroom and activity.
 *
 * The basic algorithm is driven by a 5s moving average of tempurature.  If
 * thermal headroom is available, the CPU and/or GPU power clamps may be
 * adjusted upwards.  If we hit the thermal ceiling or a thermal trigger,
 * we scale back the clamp.  Aside from trigger events (when we're critically
 * close or over our TDP) we don't adjust the clamps more than once every
 * five seconds.
 *
 * The thermal device (device 31, function 6) has a set of registers that
 * are updated by the ME firmware.  The ME should also take the clamp values
 * written to those registers and write them to the CPU, but we currently
 * bypass that functionality and write the CPU MSR directly.
 *
 * UNSUPPORTED:
 *   - dual MCP configs
 *
 * TODO:
 *   - handle CPU hotplug
 *   - provide turbo enable/disable api
 *
 * Related documents:
 *   - CDI 403777, 403778 - Auburndale EDS vol 1 & 2
 *   - CDI 401376 - Ibex Peak EDS
 *   - ref 26037, 26641 - IPS BIOS spec
 *   - ref 26489 - Nehalem BIOS writer's guide
 *   - ref 26921 - Ibex Peak BIOS Specification
 */

#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/tick.h>
#include <linux/timer.h>
#include <drm/i915_drm.h>
#include <asm/msr.h>
#include <asm/processor.h>
#include "intel_ips.h"

#define PCI_DEVICE_ID_INTEL_THERMAL_SENSOR 0x3b32

/*
 * Package level MSRs for monitor/control
 */
#define PLATFORM_INFO   0xce
#define   PLATFORM_TDP          (1<<29)
#define   PLATFORM_RATIO        (1<<28)

#define IA32_MISC_ENABLE        0x1a0
#define   IA32_MISC_TURBO_EN    (1ULL<<38)

#define TURBO_POWER_CURRENT_LIMIT       0x1ac
#define   TURBO_TDC_OVR_EN      (1UL<<31)
#define   TURBO_TDC_MASK        (0x000000007fff0000UL)
#define   TURBO_TDC_SHIFT       (16)
#define   TURBO_TDP_OVR_EN      (1UL<<15)
#define   TURBO_TDP_MASK        (0x0000000000003fffUL)

/*
 * Core/thread MSRs for monitoring
 */
#define IA32_PERF_CTL           0x199
#define   IA32_PERF_TURBO_DIS   (1ULL<<32)

/*
 * Thermal PCI device regs
 */
#define THM_CFG_TBAR    0x10
#define THM_CFG_TBAR_HI 0x14

#define THM_TSIU        0x00
#define THM_TSE         0x01
#define   TSE_EN        0xb8
#define THM_TSS         0x02
#define THM_TSTR        0x03
#define THM_TSTTP       0x04
#define THM_TSCO        0x08
#define THM_TSES        0x0c
#define THM_TSGPEN      0x0d
#define   TSGPEN_HOT_LOHI       (1<<1)
#define   TSGPEN_CRIT_LOHI      (1<<2)
#define THM_TSPC        0x0e
#define THM_PPEC        0x10
#define THM_CTA         0x12
#define THM_PTA         0x14
#define   PTA_SLOPE_MASK        (0xff00)
#define   PTA_SLOPE_SHIFT       8
#define   PTA_OFFSET_MASK       (0x00ff)
#define THM_MGTA        0x16
#define   MGTA_SLOPE_MASK       (0xff00)
#define   MGTA_SLOPE_SHIFT      8
#define   MGTA_OFFSET_MASK      (0x00ff)
#define THM_TRC         0x1a
#define   TRC_CORE2_EN  (1<<15)
#define   TRC_THM_EN    (1<<12)
#define   TRC_C6_WAR    (1<<8)
#define   TRC_CORE1_EN  (1<<7)
#define   TRC_CORE_PWR  (1<<6)
#define   TRC_PCH_EN    (1<<5)
#define   TRC_MCH_EN    (1<<4)
#define   TRC_DIMM4     (1<<3)
#define   TRC_DIMM3     (1<<2)
#define   TRC_DIMM2     (1<<1)
#define   TRC_DIMM1     (1<<0)
#define THM_TES         0x20
#define THM_TEN         0x21
#define   TEN_UPDATE_EN 1
#define THM_PSC         0x24
#define   PSC_NTG       (1<<0) /* No GFX turbo support */
#define   PSC_NTPC      (1<<1) /* No CPU turbo support */
#define   PSC_PP_DEF    (0<<2) /* Perf policy up to driver */
#define   PSP_PP_PC     (1<<2) /* BIOS prefers CPU perf */
#define   PSP_PP_BAL    (2<<2) /* BIOS wants balanced perf */
#define   PSP_PP_GFX    (3<<2) /* BIOS prefers GFX perf */
#define   PSP_PBRT      (1<<4) /* BIOS run time support */
#define THM_CTV1        0x30
#define   CTV_TEMP_ERROR (1<<15)
#define   CTV_TEMP_MASK 0x3f
#define   CTV_
#define THM_CTV2        0x32
#define THM_CEC         0x34 /* undocumented power accumulator in joules */
#define THM_AE          0x3f
#define THM_HTS         0x50 /* 32 bits */
#define   HTS_PCPL_MASK (0x7fe00000)
#define   HTS_PCPL_SHIFT 21
#define   HTS_GPL_MASK  (0x001ff000)
#define   HTS_GPL_SHIFT 12
#define   HTS_PP_MASK   (0x00000c00)
#define   HTS_PP_SHIFT  10
#define   HTS_PP_DEF    0
#define   HTS_PP_PROC   1
#define   HTS_PP_BAL    2
#define   HTS_PP_GFX    3
#define   HTS_PCTD_DIS  (1<<9)
#define   HTS_GTD_DIS   (1<<8)
#define   HTS_PTL_MASK  (0x000000fe)
#define   HTS_PTL_SHIFT 1
#define   HTS_NVV       (1<<0)
#define THM_HTSHI       0x54 /* 16 bits */
#define   HTS2_PPL_MASK         (0x03ff)
#define   HTS2_PRST_MASK        (0x3c00)
#define   HTS2_PRST_SHIFT       10
#define   HTS2_PRST_UNLOADED    0
#define   HTS2_PRST_RUNNING     1
#define   HTS2_PRST_TDISOP      2 /* turbo disabled due to power */
#define   HTS2_PRST_TDISHT      3 /* turbo disabled due to high temp */
#define   HTS2_PRST_TDISUSR     4 /* user disabled turbo */
#define   HTS2_PRST_TDISPLAT    5 /* platform disabled turbo */
#define   HTS2_PRST_TDISPM      6 /* power management disabled turbo */
#define   HTS2_PRST_TDISERR     7 /* some kind of error disabled turbo */
#define THM_PTL         0x56
#define THM_MGTV        0x58
#define   TV_MASK       0x000000000000ff00
#define   TV_SHIFT      8
#define THM_PTV         0x60
#define   PTV_MASK      0x00ff
#define THM_MMGPC       0x64
#define THM_MPPC        0x66
#define THM_MPCPC       0x68
#define THM_TSPIEN      0x82
#define   TSPIEN_AUX_LOHI       (1<<0)
#define   TSPIEN_HOT_LOHI       (1<<1)
#define   TSPIEN_CRIT_LOHI      (1<<2)
#define   TSPIEN_AUX2_LOHI      (1<<3)
#define THM_TSLOCK      0x83
#define THM_ATR         0x84
#define THM_TOF         0x87
#define THM_STS         0x98
#define   STS_PCPL_MASK         (0x7fe00000)
#define   STS_PCPL_SHIFT        21
#define   STS_GPL_MASK          (0x001ff000)
#define   STS_GPL_SHIFT         12
#define   STS_PP_MASK           (0x00000c00)
#define   STS_PP_SHIFT          10
#define   STS_PP_DEF            0
#define   STS_PP_PROC           1
#define   STS_PP_BAL            2
#define   STS_PP_GFX            3
#define   STS_PCTD_DIS          (1<<9)
#define   STS_GTD_DIS           (1<<8)
#define   STS_PTL_MASK          (0x000000fe)
#define   STS_PTL_SHIFT         1
#define   STS_NVV               (1<<0)
#define THM_SEC         0x9c
#define   SEC_ACK       (1<<0)
#define THM_TC3         0xa4
#define THM_TC1         0xa8
#define   STS_PPL_MASK          (0x0003ff00)
#define   STS_PPL_SHIFT         16
#define THM_TC2         0xac
#define THM_DTV         0xb0
#define THM_ITV         0xd8
#define   ITV_ME_SEQNO_MASK 0x00ff0000 /* ME should update every ~200ms */
#define   ITV_ME_SEQNO_SHIFT (16)
#define   ITV_MCH_TEMP_MASK 0x0000ff00
#define   ITV_MCH_TEMP_SHIFT (8)
#define   ITV_PCH_TEMP_MASK 0x000000ff

#define thm_readb(off) readb(ips->regmap + (off))
#define thm_readw(off) readw(ips->regmap + (off))
#define thm_readl(off) readl(ips->regmap + (off))
#define thm_readq(off) readq(ips->regmap + (off))

#define thm_writeb(off, val) writeb((val), ips->regmap + (off))
#define thm_writew(off, val) writew((val), ips->regmap + (off))
#define thm_writel(off, val) writel((val), ips->regmap + (off))

static const int IPS_ADJUST_PERIOD = 5000; /* ms */
static bool late_i915_load = false;

/* For initial average collection */
static const int IPS_SAMPLE_PERIOD = 200; /* ms */
static const int IPS_SAMPLE_WINDOW = 5000; /* 5s moving window of samples */
#define IPS_SAMPLE_COUNT (IPS_SAMPLE_WINDOW / IPS_SAMPLE_PERIOD)

/* Per-SKU limits */
struct ips_mcp_limits {
        int cpu_family;
        int cpu_model; /* includes extended model... */
        int mcp_power_limit; /* mW units */
        int core_power_limit;
        int mch_power_limit;
        int core_temp_limit; /* degrees C */
        int mch_temp_limit;
};

/* Max temps are -10 degrees C to avoid PROCHOT# */

struct ips_mcp_limits ips_sv_limits = {
        .mcp_power_limit = 35000,
        .core_power_limit = 29000,
        .mch_power_limit = 20000,
        .core_temp_limit = 95,
        .mch_temp_limit = 90
};

struct ips_mcp_limits ips_lv_limits = {
        .mcp_power_limit = 25000,
        .core_power_limit = 21000,
        .mch_power_limit = 13000,
        .core_temp_limit = 95,
        .mch_temp_limit = 90
};

struct ips_mcp_limits ips_ulv_limits = {
        .mcp_power_limit = 18000,
        .core_power_limit = 14000,
        .mch_power_limit = 11000,
        .core_temp_limit = 95,
        .mch_temp_limit = 90
};

struct ips_driver {
        struct pci_dev *dev;
        void *regmap;
        struct task_struct *monitor;
        struct task_struct *adjust;
        struct dentry *debug_root;

        /* Average CPU core temps (all averages in .01 degrees C for precision) */
        u16 ctv1_avg_temp;
        u16 ctv2_avg_temp;
        /* GMCH average */
        u16 mch_avg_temp;
        /* Average for the CPU (both cores?) */
        u16 mcp_avg_temp;
        /* Average power consumption (in mW) */
        u32 cpu_avg_power;
        u32 mch_avg_power;

        /* Offset values */
        u16 cta_val;
        u16 pta_val;
        u16 mgta_val;

        /* Maximums & prefs, protected by turbo status lock */
        spinlock_t turbo_status_lock;
        u16 mcp_temp_limit;
        u16 mcp_power_limit;
        u16 core_power_limit;
        u16 mch_power_limit;
        bool cpu_turbo_enabled;
        bool __cpu_turbo_on;
        bool gpu_turbo_enabled;
        bool __gpu_turbo_on;
        bool gpu_preferred;
        bool poll_turbo_status;
        bool second_cpu;
        bool turbo_toggle_allowed;
        struct ips_mcp_limits *limits;

        /* Optional MCH interfaces for if i915 is in use */
        unsigned long (*read_mch_val)(void);
        bool (*gpu_raise)(void);
        bool (*gpu_lower)(void);
        bool (*gpu_busy)(void);
        bool (*gpu_turbo_disable)(void);

        /* For restoration at unload */
        u64 orig_turbo_limit;
        u64 orig_turbo_ratios;
};

static bool
ips_gpu_turbo_enabled(struct ips_driver *ips);

/**
 * ips_cpu_busy - is CPU busy?
 * @ips: IPS driver struct
 *
 * Check CPU for load to see whether we should increase its thermal budget.
 *
 * RETURNS:
 * True if the CPU could use more power, false otherwise.
 */
static bool ips_cpu_busy(struct ips_driver *ips)
{
        if ((avenrun[0] >> FSHIFT) > 1)
                return true;

        return false;
}

/**
 * ips_cpu_raise - raise CPU power clamp
 * @ips: IPS driver struct
 *
 * Raise the CPU power clamp by %IPS_CPU_STEP, in accordance with TDP for
 * this platform.
 *
 * We do this by adjusting the TURBO_POWER_CURRENT_LIMIT MSR upwards (as
 * long as we haven't hit the TDP limit for the SKU).
 */
static void ips_cpu_raise(struct ips_driver *ips)
{
        u64 turbo_override;
        u16 cur_tdp_limit, new_tdp_limit;

        if (!ips->cpu_turbo_enabled)
                return;

        rdmsrl(TURBO_POWER_CURRENT_LIMIT, turbo_override);

        cur_tdp_limit = turbo_override & TURBO_TDP_MASK;
        new_tdp_limit = cur_tdp_limit + 8; /* 1W increase */

        /* Clamp to SKU TDP limit */
        if (((new_tdp_limit * 10) / 8) > ips->core_power_limit)
                new_tdp_limit = cur_tdp_limit;

        thm_writew(THM_MPCPC, (new_tdp_limit * 10) / 8);

        turbo_override |= TURBO_TDC_OVR_EN | TURBO_TDC_OVR_EN;
        wrmsrl(TURBO_POWER_CURRENT_LIMIT, turbo_override);

        turbo_override &= ~TURBO_TDP_MASK;
        turbo_override |= new_tdp_limit;

        wrmsrl(TURBO_POWER_CURRENT_LIMIT, turbo_override);
}

/**
 * ips_cpu_lower - lower CPU power clamp
 * @ips: IPS driver struct
 *
 * Lower CPU power clamp b %IPS_CPU_STEP if possible.
 *
 * We do this by adjusting the TURBO_POWER_CURRENT_LIMIT MSR down, going
 * as low as the platform limits will allow (though we could go lower there
 * wouldn't be much point).
 */
static void ips_cpu_lower(struct ips_driver *ips)
{
        u64 turbo_override;
        u16 cur_limit, new_limit;

        rdmsrl(TURBO_POWER_CURRENT_LIMIT, turbo_override);

        cur_limit = turbo_override & TURBO_TDP_MASK;
        new_limit = cur_limit - 8; /* 1W decrease */

        /* Clamp to SKU TDP limit */
        if (new_limit  < (ips->orig_turbo_limit & TURBO_TDP_MASK))
                new_limit = ips->orig_turbo_limit & TURBO_TDP_MASK;

        thm_writew(THM_MPCPC, (new_limit * 10) / 8);

        turbo_override |= TURBO_TDC_OVR_EN | TURBO_TDC_OVR_EN;
        wrmsrl(TURBO_POWER_CURRENT_LIMIT, turbo_override);

        turbo_override &= ~TURBO_TDP_MASK;
        turbo_override |= new_limit;

        wrmsrl(TURBO_POWER_CURRENT_LIMIT, turbo_override);
}

/**
 * do_enable_cpu_turbo - internal turbo enable function
 * @data: unused
 *
 * Internal function for actually updating MSRs.  When we enable/disable
 * turbo, we need to do it on each CPU; this function is the one called
 * by on_each_cpu() when needed.
 */
static void do_enable_cpu_turbo(void *data)
{
        u64 perf_ctl;

        rdmsrl(IA32_PERF_CTL, perf_ctl);
        if (perf_ctl & IA32_PERF_TURBO_DIS) {
                perf_ctl &= ~IA32_PERF_TURBO_DIS;
                wrmsrl(IA32_PERF_CTL, perf_ctl);
        }
}

/**
 * ips_enable_cpu_turbo - enable turbo mode on all CPUs
 * @ips: IPS driver struct
 *
 * Enable turbo mode by clearing the disable bit in IA32_PERF_CTL on
 * all logical threads.
 */
static void ips_enable_cpu_turbo(struct ips_driver *ips)
{
        /* Already on, no need to mess with MSRs */
        if (ips->__cpu_turbo_on)
                return;

        if (ips->turbo_toggle_allowed)
                on_each_cpu(do_enable_cpu_turbo, ips, 1);

        ips->__cpu_turbo_on = true;
}

/**
 * do_disable_cpu_turbo - internal turbo disable function
 * @data: unused
 *
 * Internal function for actually updating MSRs.  When we enable/disable
 * turbo, we need to do it on each CPU; this function is the one called
 * by on_each_cpu() when needed.
 */
static void do_disable_cpu_turbo(void *data)
{
        u64 perf_ctl;

        rdmsrl(IA32_PERF_CTL, perf_ctl);
        if (!(perf_ctl & IA32_PERF_TURBO_DIS)) {
                perf_ctl |= IA32_PERF_TURBO_DIS;
                wrmsrl(IA32_PERF_CTL, perf_ctl);
        }
}

/**
 * ips_disable_cpu_turbo - disable turbo mode on all CPUs
 * @ips: IPS driver struct
 *
 * Disable turbo mode by setting the disable bit in IA32_PERF_CTL on
 * all logical threads.
 */
static void ips_disable_cpu_turbo(struct ips_driver *ips)
{
        /* Already off, leave it */
        if (!ips->__cpu_turbo_on)
                return;

        if (ips->turbo_toggle_allowed)
                on_each_cpu(do_disable_cpu_turbo, ips, 1);

        ips->__cpu_turbo_on = false;
}

/**
 * ips_gpu_busy - is GPU busy?
 * @ips: IPS driver struct
 *
 * Check GPU for load to see whether we should increase its thermal budget.
 * We need to call into the i915 driver in this case.
 *
 * RETURNS:
 * True if the GPU could use more power, false otherwise.
 */
static bool ips_gpu_busy(struct ips_driver *ips)
{
        if (!ips_gpu_turbo_enabled(ips))
                return false;

        return ips->gpu_busy();
}

/**
 * ips_gpu_raise - raise GPU power clamp
 * @ips: IPS driver struct
 *
 * Raise the GPU frequency/power if possible.  We need to call into the
 * i915 driver in this case.
 */
static void ips_gpu_raise(struct ips_driver *ips)
{
        if (!ips_gpu_turbo_enabled(ips))
                return;

        if (!ips->gpu_raise())
                ips->gpu_turbo_enabled = false;

        return;
}

/**
 * ips_gpu_lower - lower GPU power clamp
 * @ips: IPS driver struct
 *
 * Lower GPU frequency/power if possible.  Need to call i915.
 */
static void ips_gpu_lower(struct ips_driver *ips)
{
        if (!ips_gpu_turbo_enabled(ips))
                return;

        if (!ips->gpu_lower())
                ips->gpu_turbo_enabled = false;

        return;
}

/**
 * ips_enable_gpu_turbo - notify the gfx driver turbo is available
 * @ips: IPS driver struct
 *
 * Call into the graphics driver indicating that it can safely use
 * turbo mode.
 */
static void ips_enable_gpu_turbo(struct ips_driver *ips)
{
        if (ips->__gpu_turbo_on)
                return;
        ips->__gpu_turbo_on = true;
}

/**
 * ips_disable_gpu_turbo - notify the gfx driver to disable turbo mode
 * @ips: IPS driver struct
 *
 * Request that the graphics driver disable turbo mode.
 */
static void ips_disable_gpu_turbo(struct ips_driver *ips)
{
        /* Avoid calling i915 if turbo is already disabled */
        if (!ips->__gpu_turbo_on)
                return;

        if (!ips->gpu_turbo_disable())
                dev_err(&ips->dev->dev, "failed to disable graphis turbo\n");
        else
                ips->__gpu_turbo_on = false;
}

/**
 * mcp_exceeded - check whether we're outside our thermal & power limits
 * @ips: IPS driver struct
 *
 * Check whether the MCP is over its thermal or power budget.
 */
static bool mcp_exceeded(struct ips_driver *ips)
{
        unsigned long flags;
        bool ret = false;
        u32 temp_limit;
        u32 avg_power;
        const char *msg = "MCP limit exceeded: ";

        spin_lock_irqsave(&ips->turbo_status_lock, flags);

        temp_limit = ips->mcp_temp_limit * 100;
        if (ips->mcp_avg_temp > temp_limit) {
                dev_info(&ips->dev->dev,
                        "%sAvg temp %u, limit %u\n", msg, ips->mcp_avg_temp,
                        temp_limit);
                ret = true;
        }

        avg_power = ips->cpu_avg_power + ips->mch_avg_power;
        if (avg_power > ips->mcp_power_limit) {
                dev_info(&ips->dev->dev,
                        "%sAvg power %u, limit %u\n", msg, avg_power,
                        ips->mcp_power_limit);
                ret = true;
        }

        spin_unlock_irqrestore(&ips->turbo_status_lock, flags);

        return ret;
}

/**
 * cpu_exceeded - check whether a CPU core is outside its limits
 * @ips: IPS driver struct
 * @cpu: CPU number to check
 *
 * Check a given CPU's average temp or power is over its limit.
 */
static bool cpu_exceeded(struct ips_driver *ips, int cpu)
{
        unsigned long flags;
        int avg;
        bool ret = false;

        spin_lock_irqsave(&ips->turbo_status_lock, flags);
        avg = cpu ? ips->ctv2_avg_temp : ips->ctv1_avg_temp;
        if (avg > (ips->limits->core_temp_limit * 100))
                ret = true;
        if (ips->cpu_avg_power > ips->core_power_limit * 100)
                ret = true;
        spin_unlock_irqrestore(&ips->turbo_status_lock, flags);

        if (ret)
                dev_info(&ips->dev->dev,
                         "CPU power or thermal limit exceeded\n");

        return ret;
}

/**
 * mch_exceeded - check whether the GPU is over budget
 * @ips: IPS driver struct
 *
 * Check the MCH temp & power against their maximums.
 */
static bool mch_exceeded(struct ips_driver *ips)
{
        unsigned long flags;
        bool ret = false;

        spin_lock_irqsave(&ips->turbo_status_lock, flags);
        if (ips->mch_avg_temp > (ips->limits->mch_temp_limit * 100))
                ret = true;
        if (ips->mch_avg_power > ips->mch_power_limit)
                ret = true;
        spin_unlock_irqrestore(&ips->turbo_status_lock, flags);

        return ret;
}

/**
 * verify_limits - verify BIOS provided limits
 * @ips: IPS structure
 *
 * BIOS can optionally provide non-default limits for power and temp.  Check
 * them here and use the defaults if the BIOS values are not provided or
 * are otherwise unusable.
 */
static void verify_limits(struct ips_driver *ips)
{
        if (ips->mcp_power_limit < ips->limits->mcp_power_limit ||
            ips->mcp_power_limit > 35000)
                ips->mcp_power_limit = ips->limits->mcp_power_limit;

        if (ips->mcp_temp_limit < ips->limits->core_temp_limit ||
            ips->mcp_temp_limit < ips->limits->mch_temp_limit ||
            ips->mcp_temp_limit > 150)
                ips->mcp_temp_limit = min(ips->limits->core_temp_limit,
                                          ips->limits->mch_temp_limit);
}

/**
 * update_turbo_limits - get various limits & settings from regs
 * @ips: IPS driver struct
 *
 * Update the IPS power & temp limits, along with turbo enable flags,
 * based on latest register contents.
 *
 * Used at init time and for runtime BIOS support, which requires polling
 * the regs for updates (as a result of AC->DC transition for example).
 *
 * LOCKING:
 * Caller must hold turbo_status_lock (outside of init)
 */
static void update_turbo_limits(struct ips_driver *ips)
{
        u32 hts = thm_readl(THM_HTS);

        ips->cpu_turbo_enabled = !(hts & HTS_PCTD_DIS);
        /* 
         * Disable turbo for now, until we can figure out why the power figures
         * are wrong
         */
        ips->cpu_turbo_enabled = false;

        if (ips->gpu_busy)
                ips->gpu_turbo_enabled = !(hts & HTS_GTD_DIS);

        ips->core_power_limit = thm_readw(THM_MPCPC);
        ips->mch_power_limit = thm_readw(THM_MMGPC);
        ips->mcp_temp_limit = thm_readw(THM_PTL);
        ips->mcp_power_limit = thm_readw(THM_MPPC);

        verify_limits(ips);
        /* Ignore BIOS CPU vs GPU pref */
}

/**
 * ips_adjust - adjust power clamp based on thermal state
 * @data: ips driver structure
 *
 * Wake up every 5s or so and check whether we should adjust the power clamp.
 * Check CPU and GPU load to determine which needs adjustment.  There are
 * several things to consider here:
 *   - do we need to adjust up or down?
 *   - is CPU busy?
 *   - is GPU busy?
 *   - is CPU in turbo?
 *   - is GPU in turbo?
 *   - is CPU or GPU preferred? (CPU is default)
 *
 * So, given the above, we do the following:
 *   - up (TDP available)
 *     - CPU not busy, GPU not busy - nothing
 *     - CPU busy, GPU not busy - adjust CPU up
 *     - CPU not busy, GPU busy - adjust GPU up
 *     - CPU busy, GPU busy - adjust preferred unit up, taking headroom from
 *       non-preferred unit if necessary
 *   - down (at TDP limit)
 *     - adjust both CPU and GPU down if possible
 *
                cpu+ gpu+       cpu+gpu-        cpu-gpu+        cpu-gpu-
cpu < gpu <     cpu+gpu+        cpu+            gpu+            nothing
cpu < gpu >=    cpu+gpu-(mcp<)  cpu+gpu-(mcp<)  gpu-            gpu-
cpu >= gpu <    cpu-gpu+(mcp<)  cpu-            cpu-gpu+(mcp<)  cpu-
cpu >= gpu >=   cpu-gpu-        cpu-gpu-        cpu-gpu-        cpu-gpu-
 *
 */
static int ips_adjust(void *data)
{
        struct ips_driver *ips = data;
        unsigned long flags;

        dev_dbg(&ips->dev->dev, "starting ips-adjust thread\n");

        /*
         * Adjust CPU and GPU clamps every 5s if needed.  Doing it more
         * often isn't recommended due to ME interaction.
         */
        do {
                bool cpu_busy = ips_cpu_busy(ips);
                bool gpu_busy = ips_gpu_busy(ips);

                spin_lock_irqsave(&ips->turbo_status_lock, flags);
                if (ips->poll_turbo_status)
                        update_turbo_limits(ips);
                spin_unlock_irqrestore(&ips->turbo_status_lock, flags);

                /* Update turbo status if necessary */
                if (ips->cpu_turbo_enabled)
                        ips_enable_cpu_turbo(ips);
                else
                        ips_disable_cpu_turbo(ips);

                if (ips->gpu_turbo_enabled)
                        ips_enable_gpu_turbo(ips);
                else
                        ips_disable_gpu_turbo(ips);

                /* We're outside our comfort zone, crank them down */
                if (mcp_exceeded(ips)) {
                        ips_cpu_lower(ips);
                        ips_gpu_lower(ips);
                        goto sleep;
                }

                if (!cpu_exceeded(ips, 0) && cpu_busy)
                        ips_cpu_raise(ips);
                else
                        ips_cpu_lower(ips);

                if (!mch_exceeded(ips) && gpu_busy)
                        ips_gpu_raise(ips);
                else
                        ips_gpu_lower(ips);

sleep:
                schedule_timeout_interruptible(msecs_to_jiffies(IPS_ADJUST_PERIOD));
        } while (!kthread_should_stop());

        dev_dbg(&ips->dev->dev, "ips-adjust thread stopped\n");

        return 0;
}

/*
 * Helpers for reading out temp/power values and calculating their
 * averages for the decision making and monitoring functions.
 */

static u16 calc_avg_temp(struct ips_driver *ips, u16 *array)
{
        u64 total = 0;
        int i;
        u16 avg;

        for (i = 0; i < IPS_SAMPLE_COUNT; i++)
                total += (u64)(array[i] * 100);

        do_div(total, IPS_SAMPLE_COUNT);

        avg = (u16)total;

        return avg;
}

static u16 read_mgtv(struct ips_driver *ips)
{
        u16 ret;
        u64 slope, offset;
        u64 val;

        val = thm_readq(THM_MGTV);
        val = (val & TV_MASK) >> TV_SHIFT;

        slope = offset = thm_readw(THM_MGTA);
        slope = (slope & MGTA_SLOPE_MASK) >> MGTA_SLOPE_SHIFT;
        offset = offset & MGTA_OFFSET_MASK;

        ret = ((val * slope + 0x40) >> 7) + offset;

        return 0; /* MCH temp reporting buggy */
}

static u16 read_ptv(struct ips_driver *ips)
{
        u16 val, slope, offset;

        slope = (ips->pta_val & PTA_SLOPE_MASK) >> PTA_SLOPE_SHIFT;
        offset = ips->pta_val & PTA_OFFSET_MASK;

        val = thm_readw(THM_PTV) & PTV_MASK;

        return val;
}

static u16 read_ctv(struct ips_driver *ips, int cpu)
{
        int reg = cpu ? THM_CTV2 : THM_CTV1;
        u16 val;

        val = thm_readw(reg);
        if (!(val & CTV_TEMP_ERROR))
                val = (val) >> 6; /* discard fractional component */
        else
                val = 0;

        return val;
}

static u32 get_cpu_power(struct ips_driver *ips, u32 *last, int period)
{
        u32 val;
        u32 ret;

        /*
         * CEC is in joules/65535.  Take difference over time to
         * get watts.
         */
        val = thm_readl(THM_CEC);

        /* period is in ms and we want mW */
        ret = (((val - *last) * 1000) / period);
        ret = (ret * 1000) / 65535;
        *last = val;

        return 0;
}

static const u16 temp_decay_factor = 2;
static u16 update_average_temp(u16 avg, u16 val)
{
        u16 ret;

        /* Multiply by 100 for extra precision */
        ret = (val * 100 / temp_decay_factor) +
                (((temp_decay_factor - 1) * avg) / temp_decay_factor);
        return ret;
}

static const u16 power_decay_factor = 2;
static u16 update_average_power(u32 avg, u32 val)
{
        u32 ret;

        ret = (val / power_decay_factor) +
                (((power_decay_factor - 1) * avg) / power_decay_factor);

        return ret;
}

static u32 calc_avg_power(struct ips_driver *ips, u32 *array)
{
        u64 total = 0;
        u32 avg;
        int i;

        for (i = 0; i < IPS_SAMPLE_COUNT; i++)
                total += array[i];

        do_div(total, IPS_SAMPLE_COUNT);
        avg = (u32)total;

        return avg;
}

static void monitor_timeout(unsigned long arg)
{
        wake_up_process((struct task_struct *)arg);
}

/**
 * ips_monitor - temp/power monitoring thread
 * @data: ips driver structure
 *
 * This is the main function for the IPS driver.  It monitors power and
 * tempurature in the MCP and adjusts CPU and GPU power clams accordingly.
 *
 * We keep a 5s moving average of power consumption and tempurature.  Using
 * that data, along with CPU vs GPU preference, we adjust the power clamps
 * up or down.
 */
static int ips_monitor(void *data)
{
        struct ips_driver *ips = data;
        struct timer_list timer;
        unsigned long seqno_timestamp, expire, last_msecs, last_sample_period;
        int i;
        u32 *cpu_samples, *mchp_samples, old_cpu_power;
        u16 *mcp_samples, *ctv1_samples, *ctv2_samples, *mch_samples;
        u8 cur_seqno, last_seqno;

        mcp_samples = kzalloc(sizeof(u16) * IPS_SAMPLE_COUNT, GFP_KERNEL);
        ctv1_samples = kzalloc(sizeof(u16) * IPS_SAMPLE_COUNT, GFP_KERNEL);
        ctv2_samples = kzalloc(sizeof(u16) * IPS_SAMPLE_COUNT, GFP_KERNEL);
        mch_samples = kzalloc(sizeof(u16) * IPS_SAMPLE_COUNT, GFP_KERNEL);
        cpu_samples = kzalloc(sizeof(u32) * IPS_SAMPLE_COUNT, GFP_KERNEL);
        mchp_samples = kzalloc(sizeof(u32) * IPS_SAMPLE_COUNT, GFP_KERNEL);
        if (!mcp_samples || !ctv1_samples || !ctv2_samples || !mch_samples ||
                        !cpu_samples || !mchp_samples) {
                dev_err(&ips->dev->dev,
                        "failed to allocate sample array, ips disabled\n");
                kfree(mcp_samples);
                kfree(ctv1_samples);
                kfree(ctv2_samples);
                kfree(mch_samples);
                kfree(cpu_samples);
                kfree(mchp_samples);
                return -ENOMEM;
        }

        last_seqno = (thm_readl(THM_ITV) & ITV_ME_SEQNO_MASK) >>
                ITV_ME_SEQNO_SHIFT;
        seqno_timestamp = get_jiffies_64();

        old_cpu_power = thm_readl(THM_CEC);
        schedule_timeout_interruptible(msecs_to_jiffies(IPS_SAMPLE_PERIOD));

        /* Collect an initial average */
        for (i = 0; i < IPS_SAMPLE_COUNT; i++) {
                u32 mchp, cpu_power;
                u16 val;

                mcp_samples[i] = read_ptv(ips);

                val = read_ctv(ips, 0);
                ctv1_samples[i] = val;

                val = read_ctv(ips, 1);
                ctv2_samples[i] = val;

                val = read_mgtv(ips);
                mch_samples[i] = val;

                cpu_power = get_cpu_power(ips, &old_cpu_power,
                                          IPS_SAMPLE_PERIOD);
                cpu_samples[i] = cpu_power;

                if (ips->read_mch_val) {
                        mchp = ips->read_mch_val();
                        mchp_samples[i] = mchp;
                }

                schedule_timeout_interruptible(msecs_to_jiffies(IPS_SAMPLE_PERIOD));
                if (kthread_should_stop())
                        break;
        }

        ips->mcp_avg_temp = calc_avg_temp(ips, mcp_samples);
        ips->ctv1_avg_temp = calc_avg_temp(ips, ctv1_samples);
        ips->ctv2_avg_temp = calc_avg_temp(ips, ctv2_samples);
        ips->mch_avg_temp = calc_avg_temp(ips, mch_samples);
        ips->cpu_avg_power = calc_avg_power(ips, cpu_samples);
        ips->mch_avg_power = calc_avg_power(ips, mchp_samples);
        kfree(mcp_samples);
        kfree(ctv1_samples);
        kfree(ctv2_samples);
        kfree(mch_samples);
        kfree(cpu_samples);
        kfree(mchp_samples);

        /* Start the adjustment thread now that we have data */
        wake_up_process(ips->adjust);

        /*
         * Ok, now we have an initial avg.  From here on out, we track the
         * running avg using a decaying average calculation.  This allows
         * us to reduce the sample frequency if the CPU and GPU are idle.
         */
        old_cpu_power = thm_readl(THM_CEC);
        schedule_timeout_interruptible(msecs_to_jiffies(IPS_SAMPLE_PERIOD));
        last_sample_period = IPS_SAMPLE_PERIOD;

        setup_deferrable_timer_on_stack(&timer, monitor_timeout,
                                        (unsigned long)current);
        do {
                u32 cpu_val, mch_val;
                u16 val;

                /* MCP itself */
                val = read_ptv(ips);
                ips->mcp_avg_temp = update_average_temp(ips->mcp_avg_temp, val);

                /* Processor 0 */
                val = read_ctv(ips, 0);
                ips->ctv1_avg_temp =
                        update_average_temp(ips->ctv1_avg_temp, val);
                /* Power */
                cpu_val = get_cpu_power(ips, &old_cpu_power,
                                        last_sample_period);
                ips->cpu_avg_power =
                        update_average_power(ips->cpu_avg_power, cpu_val);

                if (ips->second_cpu) {
                        /* Processor 1 */
                        val = read_ctv(ips, 1);
                        ips->ctv2_avg_temp =
                                update_average_temp(ips->ctv2_avg_temp, val);
                }

                /* MCH */
                val = read_mgtv(ips);
                ips->mch_avg_temp = update_average_temp(ips->mch_avg_temp, val);
                /* Power */
                if (ips->read_mch_val) {
                        mch_val = ips->read_mch_val();
                        ips->mch_avg_power =
                                update_average_power(ips->mch_avg_power,
                                                     mch_val);
                }

                /*
                 * Make sure ME is updating thermal regs.
                 * Note:
                 * If it's been more than a second since the last update,
                 * the ME is probably hung.
                 */
                cur_seqno = (thm_readl(THM_ITV) & ITV_ME_SEQNO_MASK) >>
                        ITV_ME_SEQNO_SHIFT;
                if (cur_seqno == last_seqno &&
                    time_after(jiffies, seqno_timestamp + HZ)) {
                        dev_warn(&ips->dev->dev, "ME failed to update for more than 1s, likely hung\n");
                } else {
                        seqno_timestamp = get_jiffies_64();
                        last_seqno = cur_seqno;
                }

                last_msecs = jiffies_to_msecs(jiffies);
                expire = jiffies + msecs_to_jiffies(IPS_SAMPLE_PERIOD);

                __set_current_state(TASK_INTERRUPTIBLE);
                mod_timer(&timer, expire);
                schedule();

                /* Calculate actual sample period for power averaging */
                last_sample_period = jiffies_to_msecs(jiffies) - last_msecs;
                if (!last_sample_period)
                        last_sample_period = 1;
        } while (!kthread_should_stop());

        del_timer_sync(&timer);
        destroy_timer_on_stack(&timer);

        dev_dbg(&ips->dev->dev, "ips-monitor thread stopped\n");

        return 0;
}

#if 0
#define THM_DUMPW(reg) \
        { \
        u16 val = thm_readw(reg); \
        dev_dbg(&ips->dev->dev, #reg ": 0x%04x\n", val); \
        }
#define THM_DUMPL(reg) \
        { \
        u32 val = thm_readl(reg); \
        dev_dbg(&ips->dev->dev, #reg ": 0x%08x\n", val); \
        }
#define THM_DUMPQ(reg) \
        { \
        u64 val = thm_readq(reg); \
        dev_dbg(&ips->dev->dev, #reg ": 0x%016x\n", val); \
        }

static void dump_thermal_info(struct ips_driver *ips)
{
        u16 ptl;

        ptl = thm_readw(THM_PTL);
        dev_dbg(&ips->dev->dev, "Processor temp limit: %d\n", ptl);

        THM_DUMPW(THM_CTA);
        THM_DUMPW(THM_TRC);
        THM_DUMPW(THM_CTV1);
        THM_DUMPL(THM_STS);
        THM_DUMPW(THM_PTV);
        THM_DUMPQ(THM_MGTV);
}
#endif

/**
 * ips_irq_handler - handle temperature triggers and other IPS events
 * @irq: irq number
 * @arg: unused
 *
 * Handle temperature limit trigger events, generally by lowering the clamps.
 * If we're at a critical limit, we clamp back to the lowest possible value
 * to prevent emergency shutdown.
 */
static irqreturn_t ips_irq_handler(int irq, void *arg)
{
        struct ips_driver *ips = arg;
        u8 tses = thm_readb(THM_TSES);
        u8 tes = thm_readb(THM_TES);

        if (!tses && !tes)
                return IRQ_NONE;

        dev_info(&ips->dev->dev, "TSES: 0x%02x\n", tses);
        dev_info(&ips->dev->dev, "TES: 0x%02x\n", tes);

        /* STS update from EC? */
        if (tes & 1) {
                u32 sts, tc1;

                sts = thm_readl(THM_STS);
                tc1 = thm_readl(THM_TC1);

                if (sts & STS_NVV) {
                        spin_lock(&ips->turbo_status_lock);
                        ips->core_power_limit = (sts & STS_PCPL_MASK) >>
                                STS_PCPL_SHIFT;
                        ips->mch_power_limit = (sts & STS_GPL_MASK) >>
                                STS_GPL_SHIFT;
                        /* ignore EC CPU vs GPU pref */
                        ips->cpu_turbo_enabled = !(sts & STS_PCTD_DIS);
                        /* 
                         * Disable turbo for now, until we can figure
                         * out why the power figures are wrong
                         */
                        ips->cpu_turbo_enabled = false;
                        if (ips->gpu_busy)
                                ips->gpu_turbo_enabled = !(sts & STS_GTD_DIS);
                        ips->mcp_temp_limit = (sts & STS_PTL_MASK) >>
                                STS_PTL_SHIFT;
                        ips->mcp_power_limit = (tc1 & STS_PPL_MASK) >>
                                STS_PPL_SHIFT;
                        verify_limits(ips);
                        spin_unlock(&ips->turbo_status_lock);

                        thm_writeb(THM_SEC, SEC_ACK);
                }
                thm_writeb(THM_TES, tes);
        }

        /* Thermal trip */
        if (tses) {
                dev_warn(&ips->dev->dev,
                         "thermal trip occurred, tses: 0x%04x\n", tses);
                thm_writeb(THM_TSES, tses);
        }

        return IRQ_HANDLED;
}

#ifndef CONFIG_DEBUG_FS
static void ips_debugfs_init(struct ips_driver *ips) { return; }
static void ips_debugfs_cleanup(struct ips_driver *ips) { return; }
#else

/* Expose current state and limits in debugfs if possible */

struct ips_debugfs_node {
        struct ips_driver *ips;
        char *name;
        int (*show)(struct seq_file *m, void *data);
};

static int show_cpu_temp(struct seq_file *m, void *data)
{
        struct ips_driver *ips = m->private;

        seq_printf(m, "%d.%02d\n", ips->ctv1_avg_temp / 100,
                   ips->ctv1_avg_temp % 100);

        return 0;
}

static int show_cpu_power(struct seq_file *m, void *data)
{
        struct ips_driver *ips = m->private;

        seq_printf(m, "%dmW\n", ips->cpu_avg_power);

        return 0;
}

static int show_cpu_clamp(struct seq_file *m, void *data)
{
        u64 turbo_override;
        int tdp, tdc;

        rdmsrl(TURBO_POWER_CURRENT_LIMIT, turbo_override);

        tdp = (int)(turbo_override & TURBO_TDP_MASK);
        tdc = (int)((turbo_override & TURBO_TDC_MASK) >> TURBO_TDC_SHIFT);

        /* Convert to .1W/A units */
        tdp = tdp * 10 / 8;
        tdc = tdc * 10 / 8;

        /* Watts Amperes */
        seq_printf(m, "%d.%dW %d.%dA\n", tdp / 10, tdp % 10,
                   tdc / 10, tdc % 10);

        return 0;
}

static int show_mch_temp(struct seq_file *m, void *data)
{
        struct ips_driver *ips = m->private;

        seq_printf(m, "%d.%02d\n", ips->mch_avg_temp / 100,
                   ips->mch_avg_temp % 100);

        return 0;
}

static int show_mch_power(struct seq_file *m, void *data)
{
        struct ips_driver *ips = m->private;

        seq_printf(m, "%dmW\n", ips->mch_avg_power);

        return 0;
}

static struct ips_debugfs_node ips_debug_files[] = {
        { NULL, "cpu_temp", show_cpu_temp },
        { NULL, "cpu_power", show_cpu_power },
        { NULL, "cpu_clamp", show_cpu_clamp },
        { NULL, "mch_temp", show_mch_temp },
        { NULL, "mch_power", show_mch_power },
};

static int ips_debugfs_open(struct inode *inode, struct file *file)
{
        struct ips_debugfs_node *node = inode->i_private;

        return single_open(file, node->show, node->ips);
}

static const struct file_operations ips_debugfs_ops = {
        .owner = THIS_MODULE,
        .open = ips_debugfs_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};

static void ips_debugfs_cleanup(struct ips_driver *ips)
{
        if (ips->debug_root)
                debugfs_remove_recursive(ips->debug_root);
        return;
}

static void ips_debugfs_init(struct ips_driver *ips)
{
        int i;

        ips->debug_root = debugfs_create_dir("ips", NULL);
        if (!ips->debug_root) {
                dev_err(&ips->dev->dev,
                        "failed to create debugfs entries: %ld\n",
                        PTR_ERR(ips->debug_root));
                return;
        }

        for (i = 0; i < ARRAY_SIZE(ips_debug_files); i++) {
                struct dentry *ent;
                struct ips_debugfs_node *node = &ips_debug_files[i];

                node->ips = ips;
                ent = debugfs_create_file(node->name, S_IFREG | S_IRUGO,
                                          ips->debug_root, node,
                                          &ips_debugfs_ops);
                if (!ent) {
                        dev_err(&ips->dev->dev,
                                "failed to create debug file: %ld\n",
                                PTR_ERR(ent));
                        goto err_cleanup;
                }
        }

        return;

err_cleanup:
        ips_debugfs_cleanup(ips);
        return;
}
#endif /* CONFIG_DEBUG_FS */

/**
 * ips_detect_cpu - detect whether CPU supports IPS
 *
 * Walk our list and see if we're on a supported CPU.  If we find one,
 * return the limits for it.
 */
static struct ips_mcp_limits *ips_detect_cpu(struct ips_driver *ips)
{
        u64 turbo_power, misc_en;
        struct ips_mcp_limits *limits = NULL;
        u16 tdp;

        if (!(boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model == 37)) {
                dev_info(&ips->dev->dev, "Non-IPS CPU detected.\n");
                goto out;
        }

        rdmsrl(IA32_MISC_ENABLE, misc_en);
        /*
         * If the turbo enable bit isn't set, we shouldn't try to enable/disable
         * turbo manually or we'll get an illegal MSR access, even though
         * turbo will still be available.
         */
        if (misc_en & IA32_MISC_TURBO_EN)
                ips->turbo_toggle_allowed = true;
        else
                ips->turbo_toggle_allowed = false;

        if (strstr(boot_cpu_data.x86_model_id, "CPU       M"))
                limits = &ips_sv_limits;
        else if (strstr(boot_cpu_data.x86_model_id, "CPU       L"))
                limits = &ips_lv_limits;
        else if (strstr(boot_cpu_data.x86_model_id, "CPU       U"))
                limits = &ips_ulv_limits;
        else {
                dev_info(&ips->dev->dev, "No CPUID match found.\n");
                goto out;
        }

        rdmsrl(TURBO_POWER_CURRENT_LIMIT, turbo_power);
        tdp = turbo_power & TURBO_TDP_MASK;

        /* Sanity check TDP against CPU */
        if (limits->core_power_limit != (tdp / 8) * 1000) {
                dev_info(&ips->dev->dev, "CPU TDP doesn't match expected value (found %d, expected %d)\n",
                         tdp / 8, limits->core_power_limit / 1000);
                limits->core_power_limit = (tdp / 8) * 1000;
        }

out:
        return limits;
}

/**
 * ips_get_i915_syms - try to get GPU control methods from i915 driver
 * @ips: IPS driver
 *
 * The i915 driver exports several interfaces to allow the IPS driver to
 * monitor and control graphics turbo mode.  If we can find them, we can
 * enable graphics turbo, otherwise we must disable it to avoid exceeding
 * thermal and power limits in the MCP.
 */
static bool ips_get_i915_syms(struct ips_driver *ips)
{
        ips->read_mch_val = symbol_get(i915_read_mch_val);
        if (!ips->read_mch_val)
                goto out_err;
        ips->gpu_raise = symbol_get(i915_gpu_raise);
        if (!ips->gpu_raise)
                goto out_put_mch;
        ips->gpu_lower = symbol_get(i915_gpu_lower);
        if (!ips->gpu_lower)
                goto out_put_raise;
        ips->gpu_busy = symbol_get(i915_gpu_busy);
        if (!ips->gpu_busy)
                goto out_put_lower;
        ips->gpu_turbo_disable = symbol_get(i915_gpu_turbo_disable);
        if (!ips->gpu_turbo_disable)
                goto out_put_busy;

        return true;

out_put_busy:
        symbol_put(i915_gpu_busy);
out_put_lower:
        symbol_put(i915_gpu_lower);
out_put_raise:
        symbol_put(i915_gpu_raise);
out_put_mch:
        symbol_put(i915_read_mch_val);
out_err:
        return false;
}

static bool
ips_gpu_turbo_enabled(struct ips_driver *ips)
{
        if (!ips->gpu_busy && late_i915_load) {
                if (ips_get_i915_syms(ips)) {
                        dev_info(&ips->dev->dev,
                                 "i915 driver attached, reenabling gpu turbo\n");
                        ips->gpu_turbo_enabled = !(thm_readl(THM_HTS) & HTS_GTD_DIS);
                }
        }

        return ips->gpu_turbo_enabled;
}

void
ips_link_to_i915_driver(void)
{
        /* We can't cleanly get at the various ips_driver structs from
         * this caller (the i915 driver), so just set a flag saying
         * that it's time to try getting the symbols again.
         */
        late_i915_load = true;
}
EXPORT_SYMBOL_GPL(ips_link_to_i915_driver);

static DEFINE_PCI_DEVICE_TABLE(ips_id_table) = {
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL,
                     PCI_DEVICE_ID_INTEL_THERMAL_SENSOR), },
        { 0, }
};

MODULE_DEVICE_TABLE(pci, ips_id_table);

static int ips_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
        u64 platform_info;
        struct ips_driver *ips;
        u32 hts;
        int ret = 0;
        u16 htshi, trc, trc_required_mask;
        u8 tse;

        ips = kzalloc(sizeof(struct ips_driver), GFP_KERNEL);
        if (!ips)
                return -ENOMEM;

        pci_set_drvdata(dev, ips);
        ips->dev = dev;

        ips->limits = ips_detect_cpu(ips);
        if (!ips->limits) {
                dev_info(&dev->dev, "IPS not supported on this CPU\n");
                ret = -ENXIO;
                goto error_free;
        }

        spin_lock_init(&ips->turbo_status_lock);

        ret = pci_enable_device(dev);
        if (ret) {
                dev_err(&dev->dev, "can't enable PCI device, aborting\n");
                goto error_free;
        }

        if (!pci_resource_start(dev, 0)) {
                dev_err(&dev->dev, "TBAR not assigned, aborting\n");
                ret = -ENXIO;
                goto error_free;
        }

        ret = pci_request_regions(dev, "ips thermal sensor");
        if (ret) {
                dev_err(&dev->dev, "thermal resource busy, aborting\n");
                goto error_free;
        }


        ips->regmap = ioremap(pci_resource_start(dev, 0),
                              pci_resource_len(dev, 0));
        if (!ips->regmap) {
                dev_err(&dev->dev, "failed to map thermal regs, aborting\n");
                ret = -EBUSY;
                goto error_release;
        }

        tse = thm_readb(THM_TSE);
        if (tse != TSE_EN) {
                dev_err(&dev->dev, "thermal device not enabled (0x%02x), aborting\n", tse);
                ret = -ENXIO;
                goto error_unmap;
        }

        trc = thm_readw(THM_TRC);
        trc_required_mask = TRC_CORE1_EN | TRC_CORE_PWR | TRC_MCH_EN;
        if ((trc & trc_required_mask) != trc_required_mask) {
                dev_err(&dev->dev, "thermal reporting for required devices not enabled, aborting\n");
                ret = -ENXIO;
                goto error_unmap;
        }

        if (trc & TRC_CORE2_EN)
                ips->second_cpu = true;

        update_turbo_limits(ips);
        dev_dbg(&dev->dev, "max cpu power clamp: %dW\n",
                ips->mcp_power_limit / 10);
        dev_dbg(&dev->dev, "max core power clamp: %dW\n",
                ips->core_power_limit / 10);
        /* BIOS may update limits at runtime */
        if (thm_readl(THM_PSC) & PSP_PBRT)
                ips->poll_turbo_status = true;

        if (!ips_get_i915_syms(ips)) {
                dev_err(&dev->dev, "failed to get i915 symbols, graphics turbo disabled\n");
                ips->gpu_turbo_enabled = false;
        } else {
                dev_dbg(&dev->dev, "graphics turbo enabled\n");
                ips->gpu_turbo_enabled = true;
        }

        /*
         * Check PLATFORM_INFO MSR to make sure this chip is
         * turbo capable.
         */
        rdmsrl(PLATFORM_INFO, platform_info);
        if (!(platform_info & PLATFORM_TDP)) {
                dev_err(&dev->dev, "platform indicates TDP override unavailable, aborting\n");
                ret = -ENODEV;
                goto error_unmap;
        }

        /*
         * IRQ handler for ME interaction
         * Note: don't use MSI here as the PCH has bugs.
         */
        pci_disable_msi(dev);
        ret = request_irq(dev->irq, ips_irq_handler, IRQF_SHARED, "ips",
                          ips);
        if (ret) {
                dev_err(&dev->dev, "request irq failed, aborting\n");
                goto error_unmap;
        }

        /* Enable aux, hot & critical interrupts */
        thm_writeb(THM_TSPIEN, TSPIEN_AUX2_LOHI | TSPIEN_CRIT_LOHI |
                   TSPIEN_HOT_LOHI | TSPIEN_AUX_LOHI);
        thm_writeb(THM_TEN, TEN_UPDATE_EN);

        /* Collect adjustment values */
        ips->cta_val = thm_readw(THM_CTA);
        ips->pta_val = thm_readw(THM_PTA);
        ips->mgta_val = thm_readw(THM_MGTA);

        /* Save turbo limits & ratios */
        rdmsrl(TURBO_POWER_CURRENT_LIMIT, ips->orig_turbo_limit);

        ips_disable_cpu_turbo(ips);
        ips->cpu_turbo_enabled = false;

        /* Create thermal adjust thread */
        ips->adjust = kthread_create(ips_adjust, ips, "ips-adjust");
        if (IS_ERR(ips->adjust)) {
                dev_err(&dev->dev,
                        "failed to create thermal adjust thread, aborting\n");
                ret = -ENOMEM;
                goto error_free_irq;

        }

        /*
         * Set up the work queue and monitor thread. The monitor thread
         * will wake up ips_adjust thread.
         */
        ips->monitor = kthread_run(ips_monitor, ips, "ips-monitor");
        if (IS_ERR(ips->monitor)) {
                dev_err(&dev->dev,
                        "failed to create thermal monitor thread, aborting\n");
                ret = -ENOMEM;
                goto error_thread_cleanup;
        }

        hts = (ips->core_power_limit << HTS_PCPL_SHIFT) |
                (ips->mcp_temp_limit << HTS_PTL_SHIFT) | HTS_NVV;
        htshi = HTS2_PRST_RUNNING << HTS2_PRST_SHIFT;

        thm_writew(THM_HTSHI, htshi);
        thm_writel(THM_HTS, hts);

        ips_debugfs_init(ips);

        dev_info(&dev->dev, "IPS driver initialized, MCP temp limit %d\n",
                 ips->mcp_temp_limit);
        return ret;

error_thread_cleanup:
        kthread_stop(ips->adjust);
error_free_irq:
        free_irq(ips->dev->irq, ips);
error_unmap:
        iounmap(ips->regmap);
error_release:
        pci_release_regions(dev);
error_free:
        kfree(ips);
        return ret;
}

static void ips_remove(struct pci_dev *dev)
{
        struct ips_driver *ips = pci_get_drvdata(dev);
        u64 turbo_override;

        if (!ips)
                return;

        ips_debugfs_cleanup(ips);

        /* Release i915 driver */
        if (ips->read_mch_val)
                symbol_put(i915_read_mch_val);
        if (ips->gpu_raise)
                symbol_put(i915_gpu_raise);
        if (ips->gpu_lower)
                symbol_put(i915_gpu_lower);
        if (ips->gpu_busy)
                symbol_put(i915_gpu_busy);
        if (ips->gpu_turbo_disable)
                symbol_put(i915_gpu_turbo_disable);

        rdmsrl(TURBO_POWER_CURRENT_LIMIT, turbo_override);
        turbo_override &= ~(TURBO_TDC_OVR_EN | TURBO_TDP_OVR_EN);
        wrmsrl(TURBO_POWER_CURRENT_LIMIT, turbo_override);
        wrmsrl(TURBO_POWER_CURRENT_LIMIT, ips->orig_turbo_limit);

        free_irq(ips->dev->irq, ips);
        if (ips->adjust)
                kthread_stop(ips->adjust);
        if (ips->monitor)
                kthread_stop(ips->monitor);
        iounmap(ips->regmap);
        pci_release_regions(dev);
        kfree(ips);
        dev_dbg(&dev->dev, "IPS driver removed\n");
}

#ifdef CONFIG_PM
static int ips_suspend(struct pci_dev *dev, pm_message_t state)
{
        return 0;
}

static int ips_resume(struct pci_dev *dev)
{
        return 0;
}
#else
#define ips_suspend NULL
#define ips_resume NULL
#endif /* CONFIG_PM */

static void ips_shutdown(struct pci_dev *dev)
{
}

static struct pci_driver ips_pci_driver = {
        .name = "intel ips",
        .id_table = ips_id_table,
        .probe = ips_probe,
        .remove = ips_remove,
        .suspend = ips_suspend,
        .resume = ips_resume,
        .shutdown = ips_shutdown,
};

static int __init ips_init(void)
{
        return pci_register_driver(&ips_pci_driver);
}
module_init(ips_init);

static void ips_exit(void)
{
        pci_unregister_driver(&ips_pci_driver);
        return;
}
module_exit(ips_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jesse Barnes <jbarnes@virtuousgeek.org>");
MODULE_DESCRIPTION("Intelligent Power Sharing Driver");