// SPDX-License-Identifier: MIT
#include <linux/vgaarb.h>
#include <linux/vga_switcheroo.h>

#include <drm/drm_client_event.h>

#include "nouveau_drv.h"
#include "nouveau_acpi.h"
#include "nouveau_vga.h"

static unsigned int
nouveau_vga_set_decode(struct pci_dev *pdev, bool state)
{
        struct nouveau_drm *drm = pci_get_drvdata(pdev);
        struct nvif_object *device = &drm->client.device.object;

        if (drm->client.device.info.family == NV_DEVICE_INFO_V0_CURIE &&
            drm->client.device.info.chipset >= 0x4c)
                nvif_wr32(device, 0x088060, state);
        else
        if (drm->client.device.info.chipset >= 0x40)
                nvif_wr32(device, 0x088054, state);
        else
                nvif_wr32(device, 0x001854, state);

        if (state)
                return VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
                       VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
        else
                return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
}

static void
nouveau_switcheroo_set_state(struct pci_dev *pdev,
                             enum vga_switcheroo_state state)
{
        struct nouveau_drm *drm = pci_get_drvdata(pdev);
        struct drm_device *dev = drm->dev;

        if ((nouveau_is_optimus() || nouveau_is_v1_dsm()) && state == VGA_SWITCHEROO_OFF)
                return;

        if (state == VGA_SWITCHEROO_ON) {
                pr_err("VGA switcheroo: switched nouveau on\n");
                dev->switch_power_state = DRM_SWITCH_POWER_CHANGING;
                nouveau_pmops_resume(&pdev->dev);
                dev->switch_power_state = DRM_SWITCH_POWER_ON;
        } else {
                pr_err("VGA switcheroo: switched nouveau off\n");
                dev->switch_power_state = DRM_SWITCH_POWER_CHANGING;
                nouveau_switcheroo_optimus_dsm();
                nouveau_pmops_suspend(&pdev->dev);
                dev->switch_power_state = DRM_SWITCH_POWER_OFF;
        }
}

static void
nouveau_switcheroo_reprobe(struct pci_dev *pdev)
{
        struct nouveau_drm *drm = pci_get_drvdata(pdev);
        struct drm_device *dev = drm->dev;

        drm_client_dev_hotplug(dev);
}

static bool
nouveau_switcheroo_can_switch(struct pci_dev *pdev)
{
        struct nouveau_drm *drm = pci_get_drvdata(pdev);

        /*
         * FIXME: open_count is protected by drm_global_mutex but that would lead to
         * locking inversion with the driver load path. And the access here is
         * completely racy anyway. So don't bother with locking for now.
         */
        return atomic_read(&drm->dev->open_count) == 0;
}

static const struct vga_switcheroo_client_ops
nouveau_switcheroo_ops = {
        .set_gpu_state = nouveau_switcheroo_set_state,
        .reprobe = nouveau_switcheroo_reprobe,
        .can_switch = nouveau_switcheroo_can_switch,
};

void
nouveau_vga_init(struct nouveau_drm *drm)
{
        struct drm_device *dev = drm->dev;
        bool runtime = nouveau_pmops_runtime();
        struct pci_dev *pdev;

        /* only relevant for PCI devices */
        if (!dev_is_pci(dev->dev))
                return;
        pdev = to_pci_dev(dev->dev);

        vga_client_register(pdev, nouveau_vga_set_decode);

        /* don't register Thunderbolt eGPU with vga_switcheroo */
        if (pci_is_thunderbolt_attached(pdev))
                return;

        vga_switcheroo_register_client(pdev, &nouveau_switcheroo_ops, runtime);

        if (runtime && nouveau_is_v1_dsm() && !nouveau_is_optimus())
                vga_switcheroo_init_domain_pm_ops(drm->dev->dev, &drm->vga_pm_domain);
}

void
nouveau_vga_fini(struct nouveau_drm *drm)
{
        struct drm_device *dev = drm->dev;
        bool runtime = nouveau_pmops_runtime();
        struct pci_dev *pdev;

        /* only relevant for PCI devices */
        if (!dev_is_pci(dev->dev))
                return;
        pdev = to_pci_dev(dev->dev);

        vga_client_unregister(pdev);

        if (pci_is_thunderbolt_attached(pdev))
                return;

        vga_switcheroo_unregister_client(pdev);
        if (runtime && nouveau_is_v1_dsm() && !nouveau_is_optimus())
                vga_switcheroo_fini_domain_pm_ops(drm->dev->dev);
}