/*
 * Copyright © 2012-2014 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Eugeni Dodonov <eugeni.dodonov@intel.com>
 *    Daniel Vetter <daniel.vetter@ffwll.ch>
 *
 */

#include <linux/pm_runtime.h>

#include <drm/drm_print.h>
#include <drm/intel/display_parent_interface.h>

#include "i915_drv.h"
#include "i915_trace.h"

/**
 * DOC: runtime pm
 *
 * The i915 driver supports dynamic enabling and disabling of entire hardware
 * blocks at runtime. This is especially important on the display side where
 * software is supposed to control many power gates manually on recent hardware,
 * since on the GT side a lot of the power management is done by the hardware.
 * But even there some manual control at the device level is required.
 *
 * Since i915 supports a diverse set of platforms with a unified codebase and
 * hardware engineers just love to shuffle functionality around between power
 * domains there's a sizeable amount of indirection required. This file provides
 * generic functions to the driver for grabbing and releasing references for
 * abstract power domains. It then maps those to the actual power wells
 * present for a given platform.
 */

static struct drm_i915_private *rpm_to_i915(struct intel_runtime_pm *rpm)
{
        return container_of(rpm, struct drm_i915_private, runtime_pm);
}

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)

static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
{
        if (!rpm->debug.class)
                ref_tracker_dir_init(&rpm->debug, INTEL_REFTRACK_DEAD_COUNT,
                                     "intel_runtime_pm");
}

static intel_wakeref_t
track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
{
        if (!rpm->available || rpm->no_wakeref_tracking)
                return INTEL_WAKEREF_DEF;

        return intel_ref_tracker_alloc(&rpm->debug);
}

static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
                                             intel_wakeref_t wakeref)
{
        if (!rpm->available || rpm->no_wakeref_tracking)
                return;

        intel_ref_tracker_free(&rpm->debug, wakeref);
}

static void untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
{
        ref_tracker_dir_exit(&rpm->debug);
}

static noinline void
__intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
{
        unsigned long flags;

        if (!atomic_dec_and_lock_irqsave(&rpm->wakeref_count,
                                         &rpm->debug.lock,
                                         flags))
                return;

        ref_tracker_dir_print_locked(&rpm->debug, INTEL_REFTRACK_PRINT_LIMIT);
        spin_unlock_irqrestore(&rpm->debug.lock, flags);
}

void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
                                    struct drm_printer *p)
{
        intel_ref_tracker_show(&rpm->debug, p);
}

#else

static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
{
}

static intel_wakeref_t
track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
{
        return INTEL_WAKEREF_DEF;
}

static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
                                             intel_wakeref_t wakeref)
{
}

static void
__intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
{
        atomic_dec(&rpm->wakeref_count);
}

static void
untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
{
}

#endif

static void
intel_runtime_pm_acquire(struct intel_runtime_pm *rpm, bool wakelock)
{
        if (wakelock) {
                atomic_add(1 + INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
                assert_rpm_wakelock_held(rpm);
        } else {
                atomic_inc(&rpm->wakeref_count);
                assert_rpm_raw_wakeref_held(rpm);
        }
}

static void
intel_runtime_pm_release(struct intel_runtime_pm *rpm, int wakelock)
{
        if (wakelock) {
                assert_rpm_wakelock_held(rpm);
                atomic_sub(INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
        } else {
                assert_rpm_raw_wakeref_held(rpm);
        }

        __intel_wakeref_dec_and_check_tracking(rpm);
}

static intel_wakeref_t __intel_runtime_pm_get(struct intel_runtime_pm *rpm,
                                              bool wakelock)
{
        struct drm_i915_private *i915 = rpm_to_i915(rpm);
        int ret;

        ret = pm_runtime_get_sync(rpm->kdev);
        drm_WARN_ONCE(&i915->drm, ret < 0,
                      "pm_runtime_get_sync() failed: %d\n", ret);

        intel_runtime_pm_acquire(rpm, wakelock);

        return track_intel_runtime_pm_wakeref(rpm);
}

static struct intel_runtime_pm *drm_to_rpm(const struct drm_device *drm)
{
        struct drm_i915_private *i915 = to_i915(drm);

        return &i915->runtime_pm;
}

static struct ref_tracker *i915_display_rpm_get(const struct drm_device *drm)
{
        return intel_runtime_pm_get(drm_to_rpm(drm));
}

static struct ref_tracker *i915_display_rpm_get_raw(const struct drm_device *drm)
{
        return intel_runtime_pm_get_raw(drm_to_rpm(drm));
}

static struct ref_tracker *i915_display_rpm_get_if_in_use(const struct drm_device *drm)
{
        return intel_runtime_pm_get_if_in_use(drm_to_rpm(drm));
}

static struct ref_tracker *i915_display_rpm_get_noresume(const struct drm_device *drm)
{
        return intel_runtime_pm_get_noresume(drm_to_rpm(drm));
}

static void i915_display_rpm_put(const struct drm_device *drm, struct ref_tracker *wakeref)
{
        intel_runtime_pm_put(drm_to_rpm(drm), wakeref);
}

static void i915_display_rpm_put_raw(const struct drm_device *drm, struct ref_tracker *wakeref)
{
        intel_runtime_pm_put_raw(drm_to_rpm(drm), wakeref);
}

static void i915_display_rpm_put_unchecked(const struct drm_device *drm)
{
        intel_runtime_pm_put_unchecked(drm_to_rpm(drm));
}

static bool i915_display_rpm_suspended(const struct drm_device *drm)
{
        return intel_runtime_pm_suspended(drm_to_rpm(drm));
}

static void i915_display_rpm_assert_held(const struct drm_device *drm)
{
        assert_rpm_wakelock_held(drm_to_rpm(drm));
}

static void i915_display_rpm_assert_block(const struct drm_device *drm)
{
        disable_rpm_wakeref_asserts(drm_to_rpm(drm));
}

static void i915_display_rpm_assert_unblock(const struct drm_device *drm)
{
        enable_rpm_wakeref_asserts(drm_to_rpm(drm));
}

const struct intel_display_rpm_interface i915_display_rpm_interface = {
        .get = i915_display_rpm_get,
        .get_raw = i915_display_rpm_get_raw,
        .get_if_in_use = i915_display_rpm_get_if_in_use,
        .get_noresume = i915_display_rpm_get_noresume,
        .put = i915_display_rpm_put,
        .put_raw = i915_display_rpm_put_raw,
        .put_unchecked = i915_display_rpm_put_unchecked,
        .suspended = i915_display_rpm_suspended,
        .assert_held = i915_display_rpm_assert_held,
        .assert_block = i915_display_rpm_assert_block,
        .assert_unblock = i915_display_rpm_assert_unblock
};

/**
 * intel_runtime_pm_get_raw - grab a raw runtime pm reference
 * @rpm: the intel_runtime_pm structure
 *
 * This is the unlocked version of intel_display_power_is_enabled() and should
 * only be used from error capture and recovery code where deadlocks are
 * possible.
 * This function grabs a device-level runtime pm reference (mostly used for
 * asynchronous PM management from display code) and ensures that it is powered
 * up. Raw references are not considered during wakelock assert checks.
 *
 * Any runtime pm reference obtained by this function must have a symmetric
 * call to intel_runtime_pm_put_raw() to release the reference again.
 *
 * Returns: the wakeref cookie to pass to intel_runtime_pm_put_raw(), evaluates
 * as True if the wakeref was acquired, or False otherwise.
 */
intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm)
{
        return __intel_runtime_pm_get(rpm, false);
}

/**
 * intel_runtime_pm_get - grab a runtime pm reference
 * @rpm: the intel_runtime_pm structure
 *
 * This function grabs a device-level runtime pm reference (mostly used for GEM
 * code to ensure the GTT or GT is on) and ensures that it is powered up.
 *
 * Any runtime pm reference obtained by this function must have a symmetric
 * call to intel_runtime_pm_put() to release the reference again.
 *
 * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
 */
intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm)
{
        return __intel_runtime_pm_get(rpm, true);
}

/**
 * __intel_runtime_pm_get_if_active - grab a runtime pm reference if device is active
 * @rpm: the intel_runtime_pm structure
 * @ignore_usecount: get a ref even if dev->power.usage_count is 0
 *
 * This function grabs a device-level runtime pm reference if the device is
 * already active and ensures that it is powered up. It is illegal to try
 * and access the HW should intel_runtime_pm_get_if_active() report failure.
 *
 * If @ignore_usecount is true, a reference will be acquired even if there is no
 * user requiring the device to be powered up (dev->power.usage_count == 0).
 * If the function returns false in this case then it's guaranteed that the
 * device's runtime suspend hook has been called already or that it will be
 * called (and hence it's also guaranteed that the device's runtime resume
 * hook will be called eventually).
 *
 * Any runtime pm reference obtained by this function must have a symmetric
 * call to intel_runtime_pm_put() to release the reference again.
 *
 * Returns: the wakeref cookie to pass to intel_runtime_pm_put(), evaluates
 * as True if the wakeref was acquired, or False otherwise.
 */
static intel_wakeref_t __intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm,
                                                        bool ignore_usecount)
{
        if (IS_ENABLED(CONFIG_PM)) {
                /*
                 * In cases runtime PM is disabled by the RPM core and we get
                 * an -EINVAL return value we are not supposed to call this
                 * function, since the power state is undefined. This applies
                 * atm to the late/early system suspend/resume handlers.
                 */
                if ((ignore_usecount &&
                     pm_runtime_get_if_active(rpm->kdev) <= 0) ||
                    (!ignore_usecount &&
                     pm_runtime_get_if_in_use(rpm->kdev) <= 0))
                        return NULL;
        }

        intel_runtime_pm_acquire(rpm, true);

        return track_intel_runtime_pm_wakeref(rpm);
}

intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm)
{
        return __intel_runtime_pm_get_if_active(rpm, false);
}

intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm)
{
        return __intel_runtime_pm_get_if_active(rpm, true);
}

/**
 * intel_runtime_pm_get_noresume - grab a runtime pm reference
 * @rpm: the intel_runtime_pm structure
 *
 * This function grabs a device-level runtime pm reference.
 *
 * It will _not_ resume the device but instead only get an extra wakeref.
 * Therefore it is only valid to call this functions from contexts where
 * the device is known to be active and with another wakeref previously hold.
 *
 * Any runtime pm reference obtained by this function must have a symmetric
 * call to intel_runtime_pm_put() to release the reference again.
 *
 * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
 */
intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm)
{
        assert_rpm_raw_wakeref_held(rpm);
        pm_runtime_get_noresume(rpm->kdev);

        intel_runtime_pm_acquire(rpm, true);

        return track_intel_runtime_pm_wakeref(rpm);
}

static void __intel_runtime_pm_put(struct intel_runtime_pm *rpm,
                                   intel_wakeref_t wref,
                                   bool wakelock)
{
        struct device *kdev = rpm->kdev;

        untrack_intel_runtime_pm_wakeref(rpm, wref);

        intel_runtime_pm_release(rpm, wakelock);

        pm_runtime_mark_last_busy(kdev);
        pm_runtime_put_autosuspend(kdev);
}

/**
 * intel_runtime_pm_put_raw - release a raw runtime pm reference
 * @rpm: the intel_runtime_pm structure
 * @wref: wakeref acquired for the reference that is being released
 *
 * This function drops the device-level runtime pm reference obtained by
 * intel_runtime_pm_get_raw() and might power down the corresponding
 * hardware block right away if this is the last reference.
 */
void
intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
{
        __intel_runtime_pm_put(rpm, wref, false);
}

/**
 * intel_runtime_pm_put_unchecked - release an unchecked runtime pm reference
 * @rpm: the intel_runtime_pm structure
 *
 * This function drops the device-level runtime pm reference obtained by
 * intel_runtime_pm_get() and might power down the corresponding
 * hardware block right away if this is the last reference.
 *
 * This function exists only for historical reasons and should be avoided in
 * new code, as the correctness of its use cannot be checked. Always use
 * intel_runtime_pm_put() instead.
 */
void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm)
{
        __intel_runtime_pm_put(rpm, INTEL_WAKEREF_DEF, true);
}

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
/**
 * intel_runtime_pm_put - release a runtime pm reference
 * @rpm: the intel_runtime_pm structure
 * @wref: wakeref acquired for the reference that is being released
 *
 * This function drops the device-level runtime pm reference obtained by
 * intel_runtime_pm_get() and might power down the corresponding
 * hardware block right away if this is the last reference.
 */
void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
{
        __intel_runtime_pm_put(rpm, wref, true);
}
#endif

/**
 * intel_runtime_pm_enable - enable runtime pm
 * @rpm: the intel_runtime_pm structure
 *
 * This function enables runtime pm at the end of the driver load sequence.
 *
 * Note that this function does currently not enable runtime pm for the
 * subordinate display power domains. That is done by
 * intel_power_domains_enable().
 */
void intel_runtime_pm_enable(struct intel_runtime_pm *rpm)
{
        struct drm_i915_private *i915 = rpm_to_i915(rpm);
        struct device *kdev = rpm->kdev;

        /*
         * Disable the system suspend direct complete optimization, which can
         * leave the device suspended skipping the driver's suspend handlers
         * if the device was already runtime suspended. This is needed due to
         * the difference in our runtime and system suspend sequence and
         * because the HDA driver may require us to enable the audio power
         * domain during system suspend.
         */
        dev_pm_set_driver_flags(kdev, DPM_FLAG_NO_DIRECT_COMPLETE);

        pm_runtime_set_autosuspend_delay(kdev, 10000); /* 10s */
        pm_runtime_mark_last_busy(kdev);

        /*
         * Take a permanent reference to disable the RPM functionality and drop
         * it only when unloading the driver. Use the low level get/put helpers,
         * so the driver's own RPM reference tracking asserts also work on
         * platforms without RPM support.
         */
        if (!rpm->available) {
                int ret;

                pm_runtime_dont_use_autosuspend(kdev);
                ret = pm_runtime_get_sync(kdev);
                drm_WARN(&i915->drm, ret < 0,
                         "pm_runtime_get_sync() failed: %d\n", ret);
        } else {
                pm_runtime_use_autosuspend(kdev);
        }

        /*
         *  FIXME: Temp hammer to keep autosupend disable on lmem supported platforms.
         *  As per PCIe specs 5.3.1.4.1, all iomem read write request over a PCIe
         *  function will be unsupported in case PCIe endpoint function is in D3.
         *  Let's keep i915 autosuspend control 'on' till we fix all known issue
         *  with lmem access in D3.
         */
        if (!IS_DGFX(i915))
                pm_runtime_allow(kdev);

        /*
         * The core calls the driver load handler with an RPM reference held.
         * We drop that here and will reacquire it during unloading in
         * intel_power_domains_fini().
         */
        pm_runtime_put_autosuspend(kdev);
}

void intel_runtime_pm_disable(struct intel_runtime_pm *rpm)
{
        struct drm_i915_private *i915 = rpm_to_i915(rpm);
        struct device *kdev = rpm->kdev;

        /* Transfer rpm ownership back to core */
        drm_WARN(&i915->drm, pm_runtime_get_sync(kdev) < 0,
                 "Failed to pass rpm ownership back to core\n");

        pm_runtime_dont_use_autosuspend(kdev);

        if (!rpm->available)
                pm_runtime_put(kdev);
}

void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm)
{
        struct drm_i915_private *i915 = rpm_to_i915(rpm);
        int count = atomic_read(&rpm->wakeref_count);

        intel_wakeref_auto_fini(&rpm->userfault_wakeref);

        drm_WARN(&i915->drm, count,
                 "i915 raw-wakerefs=%d wakelocks=%d on cleanup\n",
                 intel_rpm_raw_wakeref_count(count),
                 intel_rpm_wakelock_count(count));
}

void intel_runtime_pm_driver_last_release(struct intel_runtime_pm *rpm)
{
        intel_runtime_pm_driver_release(rpm);
        untrack_all_intel_runtime_pm_wakerefs(rpm);
}

void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm)
{
        struct drm_i915_private *i915 = rpm_to_i915(rpm);
        struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
        struct device *kdev = &pdev->dev;

        rpm->kdev = kdev;
        rpm->available = HAS_RUNTIME_PM(i915);
        atomic_set(&rpm->wakeref_count, 0);

        init_intel_runtime_pm_wakeref(rpm);
        INIT_LIST_HEAD(&rpm->lmem_userfault_list);
        spin_lock_init(&rpm->lmem_userfault_lock);
        intel_wakeref_auto_init(&rpm->userfault_wakeref, i915);
}