// SPDX-License-Identifier: MIT
/*
 * Copyright (C) 2016-2017 Oracle Corporation
 * This file is based on qxl_irq.c
 * Copyright 2013 Red Hat Inc.
 * Authors: Dave Airlie
 *          Alon Levy
 *          Michael Thayer <michael.thayer@oracle.com,
 *          Hans de Goede <hdegoede@redhat.com>
 */

#include <linux/pci.h>

#include <drm/drm_drv.h>
#include <drm/drm_print.h>
#include <drm/drm_probe_helper.h>

#include "vbox_drv.h"
#include "vboxvideo.h"

static void vbox_clear_irq(void)
{
        outl((u32)~0, VGA_PORT_HGSMI_HOST);
}

static u32 vbox_get_flags(struct vbox_private *vbox)
{
        return readl(vbox->guest_heap + HOST_FLAGS_OFFSET);
}

void vbox_report_hotplug(struct vbox_private *vbox)
{
        schedule_work(&vbox->hotplug_work);
}

static irqreturn_t vbox_irq_handler(int irq, void *arg)
{
        struct drm_device *dev = (struct drm_device *)arg;
        struct vbox_private *vbox = to_vbox_dev(dev);
        u32 host_flags = vbox_get_flags(vbox);

        if (!(host_flags & HGSMIHOSTFLAGS_IRQ))
                return IRQ_NONE;

        /*
         * Due to a bug in the initial host implementation of hot-plug irqs,
         * the hot-plug and cursor capability flags were never cleared.
         * Fortunately we can tell when they would have been set by checking
         * that the VSYNC flag is not set.
         */
        if (host_flags &
            (HGSMIHOSTFLAGS_HOTPLUG | HGSMIHOSTFLAGS_CURSOR_CAPABILITIES) &&
            !(host_flags & HGSMIHOSTFLAGS_VSYNC))
                vbox_report_hotplug(vbox);

        vbox_clear_irq();

        return IRQ_HANDLED;
}

/*
 * Check that the position hints provided by the host are suitable for GNOME
 * shell (i.e. all screens disjoint and hints for all enabled screens) and if
 * not replace them with default ones.  Providing valid hints improves the
 * chances that we will get a known screen layout for pointer mapping.
 */
static void validate_or_set_position_hints(struct vbox_private *vbox)
{
        struct vbva_modehint *hintsi, *hintsj;
        bool valid = true;
        u16 currentx = 0;
        int i, j;

        for (i = 0; i < vbox->num_crtcs; ++i) {
                for (j = 0; j < i; ++j) {
                        hintsi = &vbox->last_mode_hints[i];
                        hintsj = &vbox->last_mode_hints[j];

                        if (hintsi->enabled && hintsj->enabled) {
                                if (hintsi->dx >= 0xffff ||
                                    hintsi->dy >= 0xffff ||
                                    hintsj->dx >= 0xffff ||
                                    hintsj->dy >= 0xffff ||
                                    (hintsi->dx <
                                        hintsj->dx + (hintsj->cx & 0x8fff) &&
                                     hintsi->dx + (hintsi->cx & 0x8fff) >
                                        hintsj->dx) ||
                                    (hintsi->dy <
                                        hintsj->dy + (hintsj->cy & 0x8fff) &&
                                     hintsi->dy + (hintsi->cy & 0x8fff) >
                                        hintsj->dy))
                                        valid = false;
                        }
                }
        }
        if (!valid)
                for (i = 0; i < vbox->num_crtcs; ++i) {
                        if (vbox->last_mode_hints[i].enabled) {
                                vbox->last_mode_hints[i].dx = currentx;
                                vbox->last_mode_hints[i].dy = 0;
                                currentx +=
                                    vbox->last_mode_hints[i].cx & 0x8fff;
                        }
                }
}

/* Query the host for the most recent video mode hints. */
static void vbox_update_mode_hints(struct vbox_private *vbox)
{
        struct drm_connector_list_iter conn_iter;
        struct drm_device *dev = &vbox->ddev;
        struct drm_connector *connector;
        struct vbox_connector *vbox_conn;
        struct vbva_modehint *hints;
        u16 flags;
        bool disconnected;
        unsigned int crtc_id;
        int ret;

        ret = hgsmi_get_mode_hints(vbox->guest_pool, vbox->num_crtcs,
                                   vbox->last_mode_hints);
        if (ret) {
                DRM_ERROR("vboxvideo: hgsmi_get_mode_hints failed: %d\n", ret);
                return;
        }

        validate_or_set_position_hints(vbox);

        drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
        drm_connector_list_iter_begin(dev, &conn_iter);
        drm_for_each_connector_iter(connector, &conn_iter) {
                vbox_conn = to_vbox_connector(connector);

                hints = &vbox->last_mode_hints[vbox_conn->vbox_crtc->crtc_id];
                if (hints->magic != VBVAMODEHINT_MAGIC)
                        continue;

                disconnected = !(hints->enabled);
                crtc_id = vbox_conn->vbox_crtc->crtc_id;
                vbox_conn->mode_hint.width = hints->cx;
                vbox_conn->mode_hint.height = hints->cy;
                vbox_conn->vbox_crtc->x_hint = hints->dx;
                vbox_conn->vbox_crtc->y_hint = hints->dy;
                vbox_conn->mode_hint.disconnected = disconnected;

                if (vbox_conn->vbox_crtc->disconnected == disconnected)
                        continue;

                if (disconnected)
                        flags = VBVA_SCREEN_F_ACTIVE | VBVA_SCREEN_F_DISABLED;
                else
                        flags = VBVA_SCREEN_F_ACTIVE | VBVA_SCREEN_F_BLANK;

                hgsmi_process_display_info(vbox->guest_pool, crtc_id, 0, 0, 0,
                                           hints->cx * 4, hints->cx,
                                           hints->cy, 0, flags);

                vbox_conn->vbox_crtc->disconnected = disconnected;
        }
        drm_connector_list_iter_end(&conn_iter);
        drm_modeset_unlock(&dev->mode_config.connection_mutex);
}

static void vbox_hotplug_worker(struct work_struct *work)
{
        struct vbox_private *vbox = container_of(work, struct vbox_private,
                                                 hotplug_work);

        vbox_update_mode_hints(vbox);
        drm_kms_helper_hotplug_event(&vbox->ddev);
}

int vbox_irq_init(struct vbox_private *vbox)
{
        struct drm_device *dev = &vbox->ddev;
        struct pci_dev *pdev = to_pci_dev(dev->dev);

        INIT_WORK(&vbox->hotplug_work, vbox_hotplug_worker);
        vbox_update_mode_hints(vbox);

        /* PCI devices require shared interrupts. */
        return request_irq(pdev->irq, vbox_irq_handler, IRQF_SHARED, dev->driver->name, dev);
}

void vbox_irq_fini(struct vbox_private *vbox)
{
        struct drm_device *dev = &vbox->ddev;
        struct pci_dev *pdev = to_pci_dev(dev->dev);

        free_irq(pdev->irq, dev);
        flush_work(&vbox->hotplug_work);
}