/*
 * Copyright © 2016 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:
 *    Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
 *    Jerome Anand <jerome.anand@intel.com>
 *    based on VED patches
 *
 */

/**
 * DOC: LPE Audio integration for HDMI or DP playback
 *
 * Motivation:
 * Atom platforms (e.g. valleyview and cherryTrail) integrates a DMA-based
 * interface as an alternative to the traditional HDaudio path. While this
 * mode is unrelated to the LPE aka SST audio engine, the documentation refers
 * to this mode as LPE so we keep this notation for the sake of consistency.
 *
 * The interface is handled by a separate standalone driver maintained in the
 * ALSA subsystem for simplicity. To minimize the interaction between the two
 * subsystems, a bridge is setup between the hdmi-lpe-audio and i915:
 * 1. Create a platform device to share MMIO/IRQ resources
 * 2. Make the platform device child of i915 device for runtime PM.
 * 3. Create IRQ chip to forward the LPE audio irqs.
 * the hdmi-lpe-audio driver probes the lpe audio device and creates a new
 * sound card
 *
 * Threats:
 * Due to the restriction in Linux platform device model, user need manually
 * uninstall the hdmi-lpe-audio driver before uninstalling i915 module,
 * otherwise we might run into use-after-free issues after i915 removes the
 * platform device: even though hdmi-lpe-audio driver is released, the modules
 * is still in "installed" status.
 *
 * Implementation:
 * The MMIO/REG platform resources are created according to the registers
 * specification.
 * When forwarding LPE audio irqs, the flow control handler selection depends
 * on the platform, for example on valleyview handle_simple_irq is enough.
 *
 */

#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/irq.h>
#include <linux/pci.h>
#include <linux/pm_runtime.h>

#include "i915_drv.h"
#include <linux/delay.h>
#include <drm/intel_lpe_audio.h>

#define HAS_LPE_AUDIO(dev_priv) ((dev_priv)->lpe_audio.platdev != NULL)

static struct platform_device *
lpe_audio_platdev_create(struct drm_i915_private *dev_priv)
{
        struct drm_device *dev = &dev_priv->drm;
        struct platform_device_info pinfo = {};
        struct resource *rsc;
        struct platform_device *platdev;
        struct intel_hdmi_lpe_audio_pdata *pdata;

        pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
        if (!pdata)
                return ERR_PTR(-ENOMEM);

        rsc = kcalloc(2, sizeof(*rsc), GFP_KERNEL);
        if (!rsc) {
                kfree(pdata);
                return ERR_PTR(-ENOMEM);
        }

        rsc[0].start    = rsc[0].end = dev_priv->lpe_audio.irq;
        rsc[0].flags    = IORESOURCE_IRQ;
        rsc[0].name     = "hdmi-lpe-audio-irq";

        rsc[1].start    = pci_resource_start(dev->pdev, 0) +
                I915_HDMI_LPE_AUDIO_BASE;
        rsc[1].end      = pci_resource_start(dev->pdev, 0) +
                I915_HDMI_LPE_AUDIO_BASE + I915_HDMI_LPE_AUDIO_SIZE - 1;
        rsc[1].flags    = IORESOURCE_MEM;
        rsc[1].name     = "hdmi-lpe-audio-mmio";

        pinfo.parent = dev->dev;
        pinfo.name = "hdmi-lpe-audio";
        pinfo.id = -1;
        pinfo.res = rsc;
        pinfo.num_res = 2;
        pinfo.data = pdata;
        pinfo.size_data = sizeof(*pdata);
        pinfo.dma_mask = DMA_BIT_MASK(32);

        pdata->num_pipes = INTEL_INFO(dev_priv)->num_pipes;
        pdata->num_ports = IS_CHERRYVIEW(dev_priv) ? 3 : 2; /* B,C,D or B,C */
        pdata->port[0].pipe = -1;
        pdata->port[1].pipe = -1;
        pdata->port[2].pipe = -1;
        spin_lock_init(&pdata->lpe_audio_slock);

        platdev = platform_device_register_full(&pinfo);
        kfree(rsc);
        kfree(pdata);

        if (IS_ERR(platdev)) {
                DRM_ERROR("Failed to allocate LPE audio platform device\n");
                return platdev;
        }

        pm_runtime_no_callbacks(&platdev->dev);

        return platdev;
}

static void lpe_audio_platdev_destroy(struct drm_i915_private *dev_priv)
{
        /* XXX Note that platform_device_register_full() allocates a dma_mask
         * and never frees it. We can't free it here as we cannot guarantee
         * this is the last reference (i.e. that the dma_mask will not be
         * used after our unregister). So ee choose to leak the sizeof(u64)
         * allocation here - it should be fixed in the platform_device rather
         * than us fiddle with its internals.
         */

        platform_device_unregister(dev_priv->lpe_audio.platdev);
}

static void lpe_audio_irq_unmask(struct irq_data *d)
{
}

static void lpe_audio_irq_mask(struct irq_data *d)
{
}

static struct irq_chip lpe_audio_irqchip = {
        .name = "hdmi_lpe_audio_irqchip",
        .irq_mask = lpe_audio_irq_mask,
        .irq_unmask = lpe_audio_irq_unmask,
};

static int lpe_audio_irq_init(struct drm_i915_private *dev_priv)
{
        int irq = dev_priv->lpe_audio.irq;

        WARN_ON(!intel_irqs_enabled(dev_priv));
        irq_set_chip_and_handler_name(irq,
                                &lpe_audio_irqchip,
                                handle_simple_irq,
                                "hdmi_lpe_audio_irq_handler");

        return irq_set_chip_data(irq, dev_priv);
}

static bool lpe_audio_detect(struct drm_i915_private *dev_priv)
{
        int lpe_present = false;

        if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
                static const struct pci_device_id atom_hdaudio_ids[] = {
                        /* Baytrail */
                        {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x0f04)},
                        /* Braswell */
                        {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x2284)},
                        {}
                };

                if (!pci_dev_present(atom_hdaudio_ids)) {
                        DRM_INFO("HDaudio controller not detected, using LPE audio instead\n");
                        lpe_present = true;
                }
        }
        return lpe_present;
}

static int lpe_audio_setup(struct drm_i915_private *dev_priv)
{
        int ret;

        dev_priv->lpe_audio.irq = irq_alloc_desc(0);
        if (dev_priv->lpe_audio.irq < 0) {
                DRM_ERROR("Failed to allocate IRQ desc: %d\n",
                        dev_priv->lpe_audio.irq);
                ret = dev_priv->lpe_audio.irq;
                goto err;
        }

        DRM_DEBUG("irq = %d\n", dev_priv->lpe_audio.irq);

        ret = lpe_audio_irq_init(dev_priv);

        if (ret) {
                DRM_ERROR("Failed to initialize irqchip for lpe audio: %d\n",
                        ret);
                goto err_free_irq;
        }

        dev_priv->lpe_audio.platdev = lpe_audio_platdev_create(dev_priv);

        if (IS_ERR(dev_priv->lpe_audio.platdev)) {
                ret = PTR_ERR(dev_priv->lpe_audio.platdev);
                DRM_ERROR("Failed to create lpe audio platform device: %d\n",
                        ret);
                goto err_free_irq;
        }

        /* enable chicken bit; at least this is required for Dell Wyse 3040
         * with DP outputs (but only sometimes by some reason!)
         */
        I915_WRITE(VLV_AUD_CHICKEN_BIT_REG, VLV_CHICKEN_BIT_DBG_ENABLE);

        return 0;
err_free_irq:
        irq_free_desc(dev_priv->lpe_audio.irq);
err:
        dev_priv->lpe_audio.irq = -1;
        dev_priv->lpe_audio.platdev = NULL;
        return ret;
}

/**
 * intel_lpe_audio_irq_handler() - forwards the LPE audio irq
 * @dev_priv: the i915 drm device private data
 *
 * the LPE Audio irq is forwarded to the irq handler registered by LPE audio
 * driver.
 */
void intel_lpe_audio_irq_handler(struct drm_i915_private *dev_priv)
{
        int ret;

        if (!HAS_LPE_AUDIO(dev_priv))
                return;

        ret = generic_handle_irq(dev_priv->lpe_audio.irq);
        if (ret)
                DRM_ERROR_RATELIMITED("error handling LPE audio irq: %d\n",
                                ret);
}

/**
 * intel_lpe_audio_init() - detect and setup the bridge between HDMI LPE Audio
 * driver and i915
 * @dev_priv: the i915 drm device private data
 *
 * Return: 0 if successful. non-zero if detection or
 * llocation/initialization fails
 */
int intel_lpe_audio_init(struct drm_i915_private *dev_priv)
{
        int ret = -ENODEV;

        if (lpe_audio_detect(dev_priv)) {
                ret = lpe_audio_setup(dev_priv);
                if (ret < 0)
                        DRM_ERROR("failed to setup LPE Audio bridge\n");
        }
        return ret;
}

/**
 * intel_lpe_audio_teardown() - destroy the bridge between HDMI LPE
 * audio driver and i915
 * @dev_priv: the i915 drm device private data
 *
 * release all the resources for LPE audio <-> i915 bridge.
 */
void intel_lpe_audio_teardown(struct drm_i915_private *dev_priv)
{
        struct irq_desc *desc;

        if (!HAS_LPE_AUDIO(dev_priv))
                return;

        desc = irq_to_desc(dev_priv->lpe_audio.irq);

        lpe_audio_platdev_destroy(dev_priv);

        irq_free_desc(dev_priv->lpe_audio.irq);

        dev_priv->lpe_audio.irq = -1;
        dev_priv->lpe_audio.platdev = NULL;
}

/**
 * intel_lpe_audio_notify() - notify lpe audio event
 * audio driver and i915
 * @dev_priv: the i915 drm device private data
 * @pipe: pipe
 * @port: port
 * @eld : ELD data
 * @ls_clock: Link symbol clock in kHz
 * @dp_output: Driving a DP output?
 *
 * Notify lpe audio driver of eld change.
 */
void intel_lpe_audio_notify(struct drm_i915_private *dev_priv,
                            enum pipe pipe, enum port port,
                            const void *eld, int ls_clock, bool dp_output)
{
        unsigned long irqflags;
        struct intel_hdmi_lpe_audio_pdata *pdata;
        struct intel_hdmi_lpe_audio_port_pdata *ppdata;
        u32 audio_enable;

        if (!HAS_LPE_AUDIO(dev_priv))
                return;

        pdata = dev_get_platdata(&dev_priv->lpe_audio.platdev->dev);
        ppdata = &pdata->port[port - PORT_B];

        spin_lock_irqsave(&pdata->lpe_audio_slock, irqflags);

        audio_enable = I915_READ(VLV_AUD_PORT_EN_DBG(port));

        if (eld != NULL) {
                memcpy(ppdata->eld, eld, HDMI_MAX_ELD_BYTES);
                ppdata->pipe = pipe;
                ppdata->ls_clock = ls_clock;
                ppdata->dp_output = dp_output;

                /* Unmute the amp for both DP and HDMI */
                I915_WRITE(VLV_AUD_PORT_EN_DBG(port),
                           audio_enable & ~VLV_AMP_MUTE);
        } else {
                memset(ppdata->eld, 0, HDMI_MAX_ELD_BYTES);
                ppdata->pipe = -1;
                ppdata->ls_clock = 0;
                ppdata->dp_output = false;

                /* Mute the amp for both DP and HDMI */
                I915_WRITE(VLV_AUD_PORT_EN_DBG(port),
                           audio_enable | VLV_AMP_MUTE);
        }

        if (pdata->notify_audio_lpe)
                pdata->notify_audio_lpe(dev_priv->lpe_audio.platdev, port - PORT_B);

        spin_unlock_irqrestore(&pdata->lpe_audio_slock, irqflags);
}