// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2011 Texas Instruments Incorporated - https://www.ti.com/
 * Author: Rob Clark <rob.clark@linaro.org>
 */

#include <drm/drm_vblank.h>
#include <drm/drm_print.h>

#include "omap_drv.h"

struct omap_irq_wait {
        struct list_head node;
        wait_queue_head_t wq;
        u32 irqmask;
        int count;
};

/* call with wait_lock and dispc runtime held */
static void omap_irq_update(struct drm_device *dev)
{
        struct omap_drm_private *priv = dev->dev_private;
        struct omap_irq_wait *wait;
        u32 irqmask = priv->irq_mask;

        assert_spin_locked(&priv->wait_lock);

        list_for_each_entry(wait, &priv->wait_list, node)
                irqmask |= wait->irqmask;

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

        dispc_write_irqenable(priv->dispc, irqmask);
}

static void omap_irq_wait_handler(struct omap_irq_wait *wait)
{
        wait->count--;
        wake_up(&wait->wq);
}

struct omap_irq_wait * omap_irq_wait_init(struct drm_device *dev,
                u32 irqmask, int count)
{
        struct omap_drm_private *priv = dev->dev_private;
        struct omap_irq_wait *wait = kzalloc_obj(*wait);
        unsigned long flags;

        init_waitqueue_head(&wait->wq);
        wait->irqmask = irqmask;
        wait->count = count;

        spin_lock_irqsave(&priv->wait_lock, flags);
        list_add(&wait->node, &priv->wait_list);
        omap_irq_update(dev);
        spin_unlock_irqrestore(&priv->wait_lock, flags);

        return wait;
}

int omap_irq_wait(struct drm_device *dev, struct omap_irq_wait *wait,
                unsigned long timeout)
{
        struct omap_drm_private *priv = dev->dev_private;
        unsigned long flags;
        int ret;

        ret = wait_event_timeout(wait->wq, (wait->count <= 0), timeout);

        spin_lock_irqsave(&priv->wait_lock, flags);
        list_del(&wait->node);
        omap_irq_update(dev);
        spin_unlock_irqrestore(&priv->wait_lock, flags);

        kfree(wait);

        return ret == 0 ? -1 : 0;
}

int omap_irq_enable_framedone(struct drm_crtc *crtc, bool enable)
{
        struct drm_device *dev = crtc->dev;
        struct omap_drm_private *priv = dev->dev_private;
        unsigned long flags;
        enum omap_channel channel = omap_crtc_channel(crtc);
        int framedone_irq =
                dispc_mgr_get_framedone_irq(priv->dispc, channel);

        DBG("dev=%p, crtc=%u, enable=%d", dev, channel, enable);

        spin_lock_irqsave(&priv->wait_lock, flags);
        if (enable)
                priv->irq_mask |= framedone_irq;
        else
                priv->irq_mask &= ~framedone_irq;
        omap_irq_update(dev);
        spin_unlock_irqrestore(&priv->wait_lock, flags);

        return 0;
}

/**
 * omap_irq_enable_vblank - enable vblank interrupt events
 * @crtc: DRM CRTC
 *
 * 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_crtc *crtc)
{
        struct drm_device *dev = crtc->dev;
        struct omap_drm_private *priv = dev->dev_private;
        unsigned long flags;
        enum omap_channel channel = omap_crtc_channel(crtc);

        DBG("dev=%p, crtc=%u", dev, channel);

        spin_lock_irqsave(&priv->wait_lock, flags);
        priv->irq_mask |= dispc_mgr_get_vsync_irq(priv->dispc,
                                                             channel);
        omap_irq_update(dev);
        spin_unlock_irqrestore(&priv->wait_lock, flags);

        return 0;
}

/**
 * omap_irq_disable_vblank - disable vblank interrupt events
 * @crtc: DRM CRTC
 *
 * 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_crtc *crtc)
{
        struct drm_device *dev = crtc->dev;
        struct omap_drm_private *priv = dev->dev_private;
        unsigned long flags;
        enum omap_channel channel = omap_crtc_channel(crtc);

        DBG("dev=%p, crtc=%u", dev, channel);

        spin_lock_irqsave(&priv->wait_lock, flags);
        priv->irq_mask &= ~dispc_mgr_get_vsync_irq(priv->dispc,
                                                              channel);
        omap_irq_update(dev);
        spin_unlock_irqrestore(&priv->wait_lock, flags);
}

static void omap_irq_fifo_underflow(struct omap_drm_private *priv,
                                    u32 irqstatus)
{
        static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
                                      DEFAULT_RATELIMIT_BURST);
        static const struct {
                const char *name;
                u32 mask;
        } sources[] = {
                { "gfx", DISPC_IRQ_GFX_FIFO_UNDERFLOW },
                { "vid1", DISPC_IRQ_VID1_FIFO_UNDERFLOW },
                { "vid2", DISPC_IRQ_VID2_FIFO_UNDERFLOW },
                { "vid3", DISPC_IRQ_VID3_FIFO_UNDERFLOW },
        };

        const u32 mask = DISPC_IRQ_GFX_FIFO_UNDERFLOW
                       | DISPC_IRQ_VID1_FIFO_UNDERFLOW
                       | DISPC_IRQ_VID2_FIFO_UNDERFLOW
                       | DISPC_IRQ_VID3_FIFO_UNDERFLOW;
        unsigned int i;

        spin_lock(&priv->wait_lock);
        irqstatus &= priv->irq_mask & mask;
        spin_unlock(&priv->wait_lock);

        if (!irqstatus)
                return;

        if (!__ratelimit(&_rs))
                return;

        DRM_ERROR("FIFO underflow on ");

        for (i = 0; i < ARRAY_SIZE(sources); ++i) {
                if (sources[i].mask & irqstatus)
                        pr_cont("%s ", sources[i].name);
        }

        pr_cont("(0x%08x)\n", irqstatus);
}

static void omap_irq_ocp_error_handler(struct drm_device *dev,
        u32 irqstatus)
{
        if (!(irqstatus & DISPC_IRQ_OCP_ERR))
                return;

        dev_err_ratelimited(dev->dev, "OCP error\n");
}

static irqreturn_t omap_irq_handler(int irq, void *arg)
{
        struct drm_device *dev = (struct drm_device *) arg;
        struct omap_drm_private *priv = dev->dev_private;
        struct omap_irq_wait *wait, *n;
        unsigned long flags;
        unsigned int id;
        u32 irqstatus;

        irqstatus = dispc_read_irqstatus(priv->dispc);
        dispc_clear_irqstatus(priv->dispc, irqstatus);
        dispc_read_irqstatus(priv->dispc);      /* flush posted write */

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

        for (id = 0; id < priv->num_pipes; id++) {
                struct drm_crtc *crtc = priv->pipes[id].crtc;
                enum omap_channel channel = omap_crtc_channel(crtc);

                if (irqstatus & dispc_mgr_get_vsync_irq(priv->dispc, channel)) {
                        drm_handle_vblank(dev, id);
                        omap_crtc_vblank_irq(crtc);
                }

                if (irqstatus & dispc_mgr_get_sync_lost_irq(priv->dispc, channel))
                        omap_crtc_error_irq(crtc, irqstatus);

                if (irqstatus & dispc_mgr_get_framedone_irq(priv->dispc, channel))
                        omap_crtc_framedone_irq(crtc, irqstatus);
        }

        omap_irq_ocp_error_handler(dev, irqstatus);
        omap_irq_fifo_underflow(priv, irqstatus);

        spin_lock_irqsave(&priv->wait_lock, flags);
        list_for_each_entry_safe(wait, n, &priv->wait_list, node) {
                if (wait->irqmask & irqstatus)
                        omap_irq_wait_handler(wait);
        }
        spin_unlock_irqrestore(&priv->wait_lock, flags);

        return IRQ_HANDLED;
}

static const u32 omap_underflow_irqs[] = {
        [OMAP_DSS_GFX] = DISPC_IRQ_GFX_FIFO_UNDERFLOW,
        [OMAP_DSS_VIDEO1] = DISPC_IRQ_VID1_FIFO_UNDERFLOW,
        [OMAP_DSS_VIDEO2] = DISPC_IRQ_VID2_FIFO_UNDERFLOW,
        [OMAP_DSS_VIDEO3] = DISPC_IRQ_VID3_FIFO_UNDERFLOW,
};

int omap_drm_irq_install(struct drm_device *dev)
{
        struct omap_drm_private *priv = dev->dev_private;
        unsigned int num_mgrs = dispc_get_num_mgrs(priv->dispc);
        unsigned int max_planes;
        unsigned int i;
        int ret;

        spin_lock_init(&priv->wait_lock);
        INIT_LIST_HEAD(&priv->wait_list);

        priv->irq_mask = DISPC_IRQ_OCP_ERR;

        max_planes = min(ARRAY_SIZE(priv->planes),
                         ARRAY_SIZE(omap_underflow_irqs));
        for (i = 0; i < max_planes; ++i) {
                if (priv->planes[i])
                        priv->irq_mask |= omap_underflow_irqs[i];
        }

        for (i = 0; i < num_mgrs; ++i)
                priv->irq_mask |= dispc_mgr_get_sync_lost_irq(priv->dispc, i);

        dispc_runtime_get(priv->dispc);
        dispc_clear_irqstatus(priv->dispc, 0xffffffff);
        dispc_runtime_put(priv->dispc);

        ret = dispc_request_irq(priv->dispc, omap_irq_handler, dev);
        if (ret < 0)
                return ret;

        priv->irq_enabled = true;

        return 0;
}

void omap_drm_irq_uninstall(struct drm_device *dev)
{
        struct omap_drm_private *priv = dev->dev_private;

        if (!priv->irq_enabled)
                return;

        priv->irq_enabled = false;

        dispc_free_irq(priv->dispc, dev);
}