/*
 * drivers/gpu/drm/omapdrm/omap_irq.c
 *
 * Copyright (C) 2012 Texas Instruments
 * Author: Rob Clark <rob.clark@linaro.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "omap_drv.h"

static DEFINE_SPINLOCK(list_lock);

static void omap_irq_error_handler(struct omap_drm_irq *irq,
                uint32_t irqstatus)
{
        DRM_ERROR("errors: %08x\n", irqstatus);
}

/* call with list_lock and dispc runtime held */
static void omap_irq_update(struct drm_device *dev)
{
        struct omap_drm_private *priv = dev->dev_private;
        struct omap_drm_irq *irq;
        uint32_t irqmask = priv->vblank_mask;

        BUG_ON(!spin_is_locked(&list_lock));

        list_for_each_entry(irq, &priv->irq_list, node)
                irqmask |= irq->irqmask;

        DBG("irqmask=%08x", irqmask);

        dispc_write_irqenable(irqmask);
        dispc_read_irqenable();        /* flush posted write */
}

void omap_irq_register(struct drm_device *dev, struct omap_drm_irq *irq)
{
        struct omap_drm_private *priv = dev->dev_private;
        unsigned long flags;

        dispc_runtime_get();
        spin_lock_irqsave(&list_lock, flags);

        if (!WARN_ON(irq->registered)) {
                irq->registered = true;
                list_add(&irq->node, &priv->irq_list);
                omap_irq_update(dev);
        }

        spin_unlock_irqrestore(&list_lock, flags);
        dispc_runtime_put();
}

void omap_irq_unregister(struct drm_device *dev, struct omap_drm_irq *irq)
{
        unsigned long flags;

        dispc_runtime_get();
        spin_lock_irqsave(&list_lock, flags);

        if (!WARN_ON(!irq->registered)) {
                irq->registered = false;
                list_del(&irq->node);
                omap_irq_update(dev);
        }

        spin_unlock_irqrestore(&list_lock, flags);
        dispc_runtime_put();
}

struct omap_irq_wait {
        struct omap_drm_irq irq;
        int count;
};

static DECLARE_WAIT_QUEUE_HEAD(wait_event);

static void wait_irq(struct omap_drm_irq *irq, uint32_t irqstatus)
{
        struct omap_irq_wait *wait =
                        container_of(irq, struct omap_irq_wait, irq);
        wait->count--;
        wake_up_all(&wait_event);
}

struct omap_irq_wait * omap_irq_wait_init(struct drm_device *dev,
                uint32_t irqmask, int count)
{
        struct omap_irq_wait *wait = kzalloc(sizeof(*wait), GFP_KERNEL);
        wait->irq.irq = wait_irq;
        wait->irq.irqmask = irqmask;
        wait->count = count;
        omap_irq_register(dev, &wait->irq);
        return wait;
}

int omap_irq_wait(struct drm_device *dev, struct omap_irq_wait *wait,
                unsigned long timeout)
{
        int ret = wait_event_timeout(wait_event, (wait->count <= 0), timeout);
        omap_irq_unregister(dev, &wait->irq);
        kfree(wait);
        if (ret == 0)
                return -1;
        return 0;
}

/**
 * enable_vblank - enable vblank interrupt events
 * @dev: DRM device
 * @crtc: which irq to enable
 *
 * Enable vblank interrupts for @crtc.  If the device doesn't have
 * a hardware vblank counter, this routine should be a no-op, since
 * interrupts will have to stay on to keep the count accurate.
 *
 * RETURNS
 * Zero on success, appropriate errno if the given @crtc's vblank
 * interrupt cannot be enabled.
 */
int omap_irq_enable_vblank(struct drm_device *dev, int crtc_id)
{
        struct omap_drm_private *priv = dev->dev_private;
        struct drm_crtc *crtc = priv->crtcs[crtc_id];
        unsigned long flags;

        DBG("dev=%p, crtc=%d", dev, crtc_id);

        dispc_runtime_get();
        spin_lock_irqsave(&list_lock, flags);
        priv->vblank_mask |= pipe2vbl(crtc);
        omap_irq_update(dev);
        spin_unlock_irqrestore(&list_lock, flags);
        dispc_runtime_put();

        return 0;
}

/**
 * disable_vblank - disable vblank interrupt events
 * @dev: DRM device
 * @crtc: which irq to enable
 *
 * Disable vblank interrupts for @crtc.  If the device doesn't have
 * a hardware vblank counter, this routine should be a no-op, since
 * interrupts will have to stay on to keep the count accurate.
 */
void omap_irq_disable_vblank(struct drm_device *dev, int crtc_id)
{
        struct omap_drm_private *priv = dev->dev_private;
        struct drm_crtc *crtc = priv->crtcs[crtc_id];
        unsigned long flags;

        DBG("dev=%p, crtc=%d", dev, crtc_id);

        dispc_runtime_get();
        spin_lock_irqsave(&list_lock, flags);
        priv->vblank_mask &= ~pipe2vbl(crtc);
        omap_irq_update(dev);
        spin_unlock_irqrestore(&list_lock, flags);
        dispc_runtime_put();
}

irqreturn_t omap_irq_handler(DRM_IRQ_ARGS)
{
        struct drm_device *dev = (struct drm_device *) arg;
        struct omap_drm_private *priv = dev->dev_private;
        struct omap_drm_irq *handler, *n;
        unsigned long flags;
        unsigned int id;
        u32 irqstatus;

        irqstatus = dispc_read_irqstatus();
        dispc_clear_irqstatus(irqstatus);
        dispc_read_irqstatus();        /* flush posted write */

        VERB("irqs: %08x", irqstatus);

        for (id = 0; id < priv->num_crtcs; id++) {
                struct drm_crtc *crtc = priv->crtcs[id];

                if (irqstatus & pipe2vbl(crtc))
                        drm_handle_vblank(dev, id);
        }

        spin_lock_irqsave(&list_lock, flags);
        list_for_each_entry_safe(handler, n, &priv->irq_list, node) {
                if (handler->irqmask & irqstatus) {
                        spin_unlock_irqrestore(&list_lock, flags);
                        handler->irq(handler, handler->irqmask & irqstatus);
                        spin_lock_irqsave(&list_lock, flags);
                }
        }
        spin_unlock_irqrestore(&list_lock, flags);

        return IRQ_HANDLED;
}

void omap_irq_preinstall(struct drm_device *dev)
{
        DBG("dev=%p", dev);
        dispc_runtime_get();
        dispc_clear_irqstatus(0xffffffff);
        dispc_runtime_put();
}

int omap_irq_postinstall(struct drm_device *dev)
{
        struct omap_drm_private *priv = dev->dev_private;
        struct omap_drm_irq *error_handler = &priv->error_handler;

        DBG("dev=%p", dev);

        INIT_LIST_HEAD(&priv->irq_list);

        error_handler->irq = omap_irq_error_handler;
        error_handler->irqmask = DISPC_IRQ_OCP_ERR;

        /* for now ignore DISPC_IRQ_SYNC_LOST_DIGIT.. really I think
         * we just need to ignore it while enabling tv-out
         */
        error_handler->irqmask &= ~DISPC_IRQ_SYNC_LOST_DIGIT;

        omap_irq_register(dev, error_handler);

        return 0;
}

void omap_irq_uninstall(struct drm_device *dev)
{
        DBG("dev=%p", dev);
        // TODO prolly need to call drm_irq_uninstall() somewhere too
}

/*
 * We need a special version, instead of just using drm_irq_install(),
 * because we need to register the irq via omapdss.  Once omapdss and
 * omapdrm are merged together we can assign the dispc hwmod data to
 * ourselves and drop these and just use drm_irq_{install,uninstall}()
 */

int omap_drm_irq_install(struct drm_device *dev)
{
        int ret;

        mutex_lock(&dev->struct_mutex);

        if (dev->irq_enabled) {
                mutex_unlock(&dev->struct_mutex);
                return -EBUSY;
        }
        dev->irq_enabled = 1;
        mutex_unlock(&dev->struct_mutex);

        /* Before installing handler */
        if (dev->driver->irq_preinstall)
                dev->driver->irq_preinstall(dev);

        ret = dispc_request_irq(dev->driver->irq_handler, dev);

        if (ret < 0) {
                mutex_lock(&dev->struct_mutex);
                dev->irq_enabled = 0;
                mutex_unlock(&dev->struct_mutex);
                return ret;
        }

        /* After installing handler */
        if (dev->driver->irq_postinstall)
                ret = dev->driver->irq_postinstall(dev);

        if (ret < 0) {
                mutex_lock(&dev->struct_mutex);
                dev->irq_enabled = 0;
                mutex_unlock(&dev->struct_mutex);
                dispc_free_irq(dev);
        }

        return ret;
}

int omap_drm_irq_uninstall(struct drm_device *dev)
{
        unsigned long irqflags;
        int irq_enabled, i;

        mutex_lock(&dev->struct_mutex);
        irq_enabled = dev->irq_enabled;
        dev->irq_enabled = 0;
        mutex_unlock(&dev->struct_mutex);

        /*
         * Wake up any waiters so they don't hang.
         */
        if (dev->num_crtcs) {
                spin_lock_irqsave(&dev->vbl_lock, irqflags);
                for (i = 0; i < dev->num_crtcs; i++) {
                        DRM_WAKEUP(&dev->vbl_queue[i]);
                        dev->vblank_enabled[i] = 0;
                        dev->last_vblank[i] =
                                dev->driver->get_vblank_counter(dev, i);
                }
                spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
        }

        if (!irq_enabled)
                return -EINVAL;

        if (dev->driver->irq_uninstall)
                dev->driver->irq_uninstall(dev);

        dispc_free_irq(dev);

        return 0;
}