/*
 *  hdac_i915.c - routines for sync between HD-A core and i915 display driver
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License as published by the Free
 *  Software Foundation; either version 2 of the License, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that 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.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/component.h>
#include <drm/i915_component.h>
#include <sound/core.h>
#include <sound/hdaudio.h>
#include <sound/hda_i915.h>
#include <sound/hda_register.h>

static struct i915_audio_component *hdac_acomp;

/**
 * snd_hdac_set_codec_wakeup - Enable / disable HDMI/DP codec wakeup
 * @bus: HDA core bus
 * @enable: enable or disable the wakeup
 *
 * This function is supposed to be used only by a HD-audio controller
 * driver that needs the interaction with i915 graphics.
 *
 * This function should be called during the chip reset, also called at
 * resume for updating STATESTS register read.
 *
 * Returns zero for success or a negative error code.
 */
int snd_hdac_set_codec_wakeup(struct hdac_bus *bus, bool enable)
{
        struct i915_audio_component *acomp = bus->audio_component;

        if (!acomp || !acomp->ops)
                return -ENODEV;

        if (!acomp->ops->codec_wake_override) {
                dev_warn(bus->dev,
                        "Invalid codec wake callback\n");
                return 0;
        }

        dev_dbg(bus->dev, "%s codec wakeup\n",
                enable ? "enable" : "disable");

        acomp->ops->codec_wake_override(acomp->dev, enable);

        return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_set_codec_wakeup);

/**
 * snd_hdac_display_power - Power up / down the power refcount
 * @bus: HDA core bus
 * @enable: power up or down
 *
 * This function is supposed to be used only by a HD-audio controller
 * driver that needs the interaction with i915 graphics.
 *
 * This function manages a refcount and calls the i915 get_power() and
 * put_power() ops accordingly, toggling the codec wakeup, too.
 *
 * Returns zero for success or a negative error code.
 */
int snd_hdac_display_power(struct hdac_bus *bus, bool enable)
{
        struct i915_audio_component *acomp = bus->audio_component;

        if (!acomp || !acomp->ops)
                return -ENODEV;

        dev_dbg(bus->dev, "display power %s\n",
                enable ? "enable" : "disable");

        if (enable) {
                if (!bus->i915_power_refcount++) {
                        acomp->ops->get_power(acomp->dev);
                        snd_hdac_set_codec_wakeup(bus, true);
                        snd_hdac_set_codec_wakeup(bus, false);
                }
        } else {
                WARN_ON(!bus->i915_power_refcount);
                if (!--bus->i915_power_refcount)
                        acomp->ops->put_power(acomp->dev);
        }

        return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_display_power);

#define CONTROLLER_IN_GPU(pci) (((pci)->device == 0x0a0c) || \
                                ((pci)->device == 0x0c0c) || \
                                ((pci)->device == 0x0d0c) || \
                                ((pci)->device == 0x160c))

/**
 * snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW
 * @bus: HDA core bus
 *
 * Intel HSW/BDW display HDA controller is in GPU. Both its power and link BCLK
 * depends on GPU. Two Extended Mode registers EM4 (M value) and EM5 (N Value)
 * are used to convert CDClk (Core Display Clock) to 24MHz BCLK:
 * BCLK = CDCLK * M / N
 * The values will be lost when the display power well is disabled and need to
 * be restored to avoid abnormal playback speed.
 *
 * Call this function at initializing and changing power well, as well as
 * at ELD notifier for the hotplug.
 */
void snd_hdac_i915_set_bclk(struct hdac_bus *bus)
{
        struct i915_audio_component *acomp = bus->audio_component;
        struct pci_dev *pci = to_pci_dev(bus->dev);
        int cdclk_freq;
        unsigned int bclk_m, bclk_n;

        if (!acomp || !acomp->ops || !acomp->ops->get_cdclk_freq)
                return; /* only for i915 binding */
        if (!CONTROLLER_IN_GPU(pci))
                return; /* only HSW/BDW */

        cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev);
        switch (cdclk_freq) {
        case 337500:
                bclk_m = 16;
                bclk_n = 225;
                break;

        case 450000:
        default: /* default CDCLK 450MHz */
                bclk_m = 4;
                bclk_n = 75;
                break;

        case 540000:
                bclk_m = 4;
                bclk_n = 90;
                break;

        case 675000:
                bclk_m = 8;
                bclk_n = 225;
                break;
        }

        snd_hdac_chip_writew(bus, HSW_EM4, bclk_m);
        snd_hdac_chip_writew(bus, HSW_EM5, bclk_n);
}
EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);

/* There is a fixed mapping between audio pin node and display port
 * on current Intel platforms:
 * Pin Widget 5 - PORT B (port = 1 in i915 driver)
 * Pin Widget 6 - PORT C (port = 2 in i915 driver)
 * Pin Widget 7 - PORT D (port = 3 in i915 driver)
 */
static int pin2port(hda_nid_t pin_nid)
{
        if (WARN_ON(pin_nid < 5 || pin_nid > 7))
                return -1;
        return pin_nid - 4;
}

/**
 * snd_hdac_sync_audio_rate - Set N/CTS based on the sample rate
 * @bus: HDA core bus
 * @nid: the pin widget NID
 * @rate: the sample rate to set
 *
 * This function is supposed to be used only by a HD-audio controller
 * driver that needs the interaction with i915 graphics.
 *
 * This function sets N/CTS value based on the given sample rate.
 * Returns zero for success, or a negative error code.
 */
int snd_hdac_sync_audio_rate(struct hdac_bus *bus, hda_nid_t nid, int rate)
{
        struct i915_audio_component *acomp = bus->audio_component;
        int port;

        if (!acomp || !acomp->ops || !acomp->ops->sync_audio_rate)
                return -ENODEV;
        port = pin2port(nid);
        if (port < 0)
                return -EINVAL;
        return acomp->ops->sync_audio_rate(acomp->dev, port, rate);
}
EXPORT_SYMBOL_GPL(snd_hdac_sync_audio_rate);

/**
 * snd_hdac_acomp_get_eld - Get the audio state and ELD via component
 * @bus: HDA core bus
 * @nid: the pin widget NID
 * @audio_enabled: the pointer to store the current audio state
 * @buffer: the buffer pointer to store ELD bytes
 * @max_bytes: the max bytes to be stored on @buffer
 *
 * This function is supposed to be used only by a HD-audio controller
 * driver that needs the interaction with i915 graphics.
 *
 * This function queries the current state of the audio on the given
 * digital port and fetches the ELD bytes onto the given buffer.
 * It returns the number of bytes for the total ELD data, zero for
 * invalid ELD, or a negative error code.
 *
 * The return size is the total bytes required for the whole ELD bytes,
 * thus it may be over @max_bytes.  If it's over @max_bytes, it implies
 * that only a part of ELD bytes have been fetched.
 */
int snd_hdac_acomp_get_eld(struct hdac_bus *bus, hda_nid_t nid,
                           bool *audio_enabled, char *buffer, int max_bytes)
{
        struct i915_audio_component *acomp = bus->audio_component;
        int port;

        if (!acomp || !acomp->ops || !acomp->ops->get_eld)
                return -ENODEV;

        port = pin2port(nid);
        if (port < 0)
                return -EINVAL;
        return acomp->ops->get_eld(acomp->dev, port, audio_enabled,
                                   buffer, max_bytes);
}
EXPORT_SYMBOL_GPL(snd_hdac_acomp_get_eld);

static int hdac_component_master_bind(struct device *dev)
{
        struct i915_audio_component *acomp = hdac_acomp;
        int ret;

        ret = component_bind_all(dev, acomp);
        if (ret < 0)
                return ret;

        if (WARN_ON(!(acomp->dev && acomp->ops && acomp->ops->get_power &&
                      acomp->ops->put_power && acomp->ops->get_cdclk_freq))) {
                ret = -EINVAL;
                goto out_unbind;
        }

        /*
         * Atm, we don't support dynamic unbinding initiated by the child
         * component, so pin its containing module until we unbind.
         */
        if (!try_module_get(acomp->ops->owner)) {
                ret = -ENODEV;
                goto out_unbind;
        }

        return 0;

out_unbind:
        component_unbind_all(dev, acomp);

        return ret;
}

static void hdac_component_master_unbind(struct device *dev)
{
        struct i915_audio_component *acomp = hdac_acomp;

        module_put(acomp->ops->owner);
        component_unbind_all(dev, acomp);
        WARN_ON(acomp->ops || acomp->dev);
}

static const struct component_master_ops hdac_component_master_ops = {
        .bind = hdac_component_master_bind,
        .unbind = hdac_component_master_unbind,
};

static int hdac_component_master_match(struct device *dev, void *data)
{
        /* i915 is the only supported component */
        return !strcmp(dev->driver->name, "i915");
}

/**
 * snd_hdac_i915_register_notifier - Register i915 audio component ops
 * @aops: i915 audio component ops
 *
 * This function is supposed to be used only by a HD-audio controller
 * driver that needs the interaction with i915 graphics.
 *
 * This function sets the given ops to be called by the i915 graphics driver.
 *
 * Returns zero for success or a negative error code.
 */
int snd_hdac_i915_register_notifier(const struct i915_audio_component_audio_ops *aops)
{
        if (WARN_ON(!hdac_acomp))
                return -ENODEV;

        hdac_acomp->audio_ops = aops;
        return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_i915_register_notifier);

/* check whether intel graphics is present */
static bool i915_gfx_present(void)
{
        static struct pci_device_id ids[] = {
                { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
                  .class = PCI_BASE_CLASS_DISPLAY << 16,
                  .class_mask = 0xff << 16 },
                {}
        };
        return pci_dev_present(ids);
}

/**
 * snd_hdac_i915_init - Initialize i915 audio component
 * @bus: HDA core bus
 *
 * This function is supposed to be used only by a HD-audio controller
 * driver that needs the interaction with i915 graphics.
 *
 * This function initializes and sets up the audio component to communicate
 * with i915 graphics driver.
 *
 * Returns zero for success or a negative error code.
 */
int snd_hdac_i915_init(struct hdac_bus *bus)
{
        struct component_match *match = NULL;
        struct device *dev = bus->dev;
        struct i915_audio_component *acomp;
        int ret;

        if (!i915_gfx_present())
                return -ENODEV;

        acomp = kzalloc(sizeof(*acomp), GFP_KERNEL);
        if (!acomp)
                return -ENOMEM;
        bus->audio_component = acomp;
        hdac_acomp = acomp;

        component_match_add(dev, &match, hdac_component_master_match, bus);
        ret = component_master_add_with_match(dev, &hdac_component_master_ops,
                                              match);
        if (ret < 0)
                goto out_err;

        /*
         * Atm, we don't support deferring the component binding, so make sure
         * i915 is loaded and that the binding successfully completes.
         */
        request_module("i915");

        if (!acomp->ops) {
                ret = -ENODEV;
                goto out_master_del;
        }
        dev_dbg(dev, "bound to i915 component master\n");

        return 0;
out_master_del:
        component_master_del(dev, &hdac_component_master_ops);
out_err:
        kfree(acomp);
        bus->audio_component = NULL;
        dev_info(dev, "failed to add i915 component master (%d)\n", ret);

        return ret;
}
EXPORT_SYMBOL_GPL(snd_hdac_i915_init);

/**
 * snd_hdac_i915_exit - Finalize i915 audio component
 * @bus: HDA core bus
 *
 * This function is supposed to be used only by a HD-audio controller
 * driver that needs the interaction with i915 graphics.
 *
 * This function releases the i915 audio component that has been used.
 *
 * Returns zero for success or a negative error code.
 */
int snd_hdac_i915_exit(struct hdac_bus *bus)
{
        struct device *dev = bus->dev;
        struct i915_audio_component *acomp = bus->audio_component;

        if (!acomp)
                return 0;

        WARN_ON(bus->i915_power_refcount);
        if (bus->i915_power_refcount > 0 && acomp->ops)
                acomp->ops->put_power(acomp->dev);

        component_master_del(dev, &hdac_component_master_ops);

        kfree(acomp);
        bus->audio_component = NULL;

        return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_i915_exit);