// SPDX-License-Identifier: GPL-2.0-only OR MIT
/* Copyright 2021 Alyssa Rosenzweig <alyssa@rosenzweig.io> */
/* Based on meson driver which is
 * Copyright (C) 2016 BayLibre, SAS
 * Author: Neil Armstrong <narmstrong@baylibre.com>
 * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
 * Copyright (C) 2014 Endless Mobile
 */

#include <linux/component.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/aperture.h>

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_fbdev_dma.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_fb_dma_helper.h>
#include <drm/drm_gem_dma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_simple_kms_helper.h>
#include <drm/drm_mode.h>
#include <drm/drm_modeset_helper.h>
#include <drm/drm_module.h>
#include <drm/drm_of.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_vblank.h>
#include <drm/drm_fixed.h>
#include <drm/clients/drm_client_setup.h>

#include "dcp.h"

#define DRIVER_NAME     "apple"
#define DRIVER_DESC     "Apple display controller DRM driver"

#define FRAC_16_16(mult, div)    (((mult) << 16) / (div))

#define MAX_COPROCESSORS 2

struct apple_drm_private {
        struct drm_device drm;
};

DEFINE_DRM_GEM_DMA_FOPS(apple_fops);

#define DART_PAGE_SIZE 16384

static int apple_drm_gem_dumb_create(struct drm_file *file_priv,
                            struct drm_device *drm,
                            struct drm_mode_create_dumb *args)
{
        args->pitch = ALIGN(DIV_ROUND_UP(args->width * args->bpp, 8), 64);
        args->size = round_up(args->pitch * args->height, DART_PAGE_SIZE);

        return drm_gem_dma_dumb_create_internal(file_priv, drm, args);
}

static const struct drm_driver apple_drm_driver = {
        DRM_GEM_DMA_DRIVER_OPS_WITH_DUMB_CREATE(apple_drm_gem_dumb_create),
        DRM_FBDEV_DMA_DRIVER_OPS,
        .name                   = DRIVER_NAME,
        .desc                   = DRIVER_DESC,
        .major                  = 1,
        .minor                  = 0,
        .driver_features        = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
        .fops                   = &apple_fops,
};

static int apple_plane_atomic_check(struct drm_plane *plane,
                                    struct drm_atomic_state *state)
{
        struct drm_plane_state *new_plane_state;
        struct drm_crtc_state *crtc_state;

        new_plane_state = drm_atomic_get_new_plane_state(state, plane);

        if (!new_plane_state->crtc)
                return 0;

        crtc_state = drm_atomic_get_crtc_state(state, new_plane_state->crtc);
        if (IS_ERR(crtc_state))
                return PTR_ERR(crtc_state);

        /*
         * DCP limits downscaling to 2x and upscaling to 4x. Attempting to
         * scale outside these bounds errors out when swapping.
         *
         * This function also takes care of clipping the src/dest rectangles,
         * which is required for correct operation. Partially off-screen
         * surfaces may appear corrupted.
         *
         * DCP does not distinguish plane types in the hardware, so we set
         * can_position. If the primary plane does not fill the screen, the
         * hardware will fill in zeroes (black).
         */
        return drm_atomic_helper_check_plane_state(new_plane_state,
                                                   crtc_state,
                                                   FRAC_16_16(1, 4),
                                                   FRAC_16_16(2, 1),
                                                   true, true);
}

static void apple_plane_atomic_update(struct drm_plane *plane,
                                      struct drm_atomic_state *state)
{
        /* Handled in atomic_flush */
}

static const struct drm_plane_helper_funcs apple_plane_helper_funcs = {
        .atomic_check   = apple_plane_atomic_check,
        .atomic_update  = apple_plane_atomic_update,
};

static void apple_plane_cleanup(struct drm_plane *plane)
{
        drm_plane_cleanup(plane);
        kfree(plane);
}

static const struct drm_plane_funcs apple_plane_funcs = {
        .update_plane           = drm_atomic_helper_update_plane,
        .disable_plane          = drm_atomic_helper_disable_plane,
        .destroy                = apple_plane_cleanup,
        .reset                  = drm_atomic_helper_plane_reset,
        .atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
        .atomic_destroy_state   = drm_atomic_helper_plane_destroy_state,
};

/*
 * Table of supported formats, mapping from DRM fourccs to DCP fourccs.
 *
 * For future work, DCP supports more formats not listed, including YUV
 * formats, an extra RGBA format, and a biplanar RGB10_A8 format (fourcc b3a8)
 * used for HDR.
 *
 * Note: we don't have non-alpha formats but userspace breaks without XRGB. It
 * doesn't matter for the primary plane, but cursors/overlays must not
 * advertise formats without alpha.
 */
static const u32 dcp_formats[] = {
        DRM_FORMAT_XRGB2101010,
        DRM_FORMAT_XRGB8888,
        DRM_FORMAT_ARGB8888,
        DRM_FORMAT_XBGR8888,
        DRM_FORMAT_ABGR8888,
};

u64 apple_format_modifiers[] = {
        DRM_FORMAT_MOD_LINEAR,
        DRM_FORMAT_MOD_INVALID
};

static struct drm_plane *apple_plane_init(struct drm_device *dev,
                                          unsigned long possible_crtcs,
                                          enum drm_plane_type type)
{
        int ret;
        struct drm_plane *plane;

        plane = kzalloc(sizeof(*plane), GFP_KERNEL);

        ret = drm_universal_plane_init(dev, plane, possible_crtcs,
                                       &apple_plane_funcs,
                                       dcp_formats, ARRAY_SIZE(dcp_formats),
                                       apple_format_modifiers, type, NULL);
        if (ret)
                return ERR_PTR(ret);

        drm_plane_helper_add(plane, &apple_plane_helper_funcs);

        return plane;
}

static enum drm_connector_status
apple_connector_detect(struct drm_connector *connector, bool force)
{
        struct apple_connector *apple_connector = to_apple_connector(connector);

        return apple_connector->connected ? connector_status_connected :
                                                  connector_status_disconnected;
}

static void apple_crtc_atomic_enable(struct drm_crtc *crtc,
                                     struct drm_atomic_state *state)
{
        struct drm_crtc_state *crtc_state;
        crtc_state = drm_atomic_get_new_crtc_state(state, crtc);

        if (crtc_state->active_changed && crtc_state->active) {
                struct apple_crtc *apple_crtc = to_apple_crtc(crtc);
                dcp_poweron(apple_crtc->dcp);
        }

        if (crtc_state->active)
                dcp_crtc_atomic_modeset(crtc, state);
}

static void apple_crtc_atomic_disable(struct drm_crtc *crtc,
                                      struct drm_atomic_state *state)
{
        struct drm_crtc_state *crtc_state;
        crtc_state = drm_atomic_get_new_crtc_state(state, crtc);

        if (crtc_state->active_changed && !crtc_state->active) {
                struct apple_crtc *apple_crtc = to_apple_crtc(crtc);
                dcp_poweroff(apple_crtc->dcp);
        }

        if (crtc->state->event && !crtc->state->active) {
                spin_lock_irq(&crtc->dev->event_lock);
                drm_crtc_send_vblank_event(crtc, crtc->state->event);
                spin_unlock_irq(&crtc->dev->event_lock);

                crtc->state->event = NULL;
        }
}

static void apple_crtc_atomic_begin(struct drm_crtc *crtc,
                                    struct drm_atomic_state *state)
{
        struct apple_crtc *apple_crtc = to_apple_crtc(crtc);
        unsigned long flags;

        if (crtc->state->event) {
                spin_lock_irqsave(&crtc->dev->event_lock, flags);
                apple_crtc->event = crtc->state->event;
                spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
                crtc->state->event = NULL;
        }
}

static void dcp_atomic_commit_tail(struct drm_atomic_state *old_state)
{
        struct drm_device *dev = old_state->dev;

        drm_atomic_helper_commit_modeset_disables(dev, old_state);

        drm_atomic_helper_commit_modeset_enables(dev, old_state);

        drm_atomic_helper_commit_planes(dev, old_state,
                                        DRM_PLANE_COMMIT_ACTIVE_ONLY);

        drm_atomic_helper_fake_vblank(old_state);

        drm_atomic_helper_commit_hw_done(old_state);

        drm_atomic_helper_wait_for_flip_done(dev, old_state);

        drm_atomic_helper_cleanup_planes(dev, old_state);
}

static void apple_crtc_cleanup(struct drm_crtc *crtc)
{
        drm_crtc_cleanup(crtc);
        kfree(to_apple_crtc(crtc));
}

static const struct drm_crtc_funcs apple_crtc_funcs = {
        .atomic_destroy_state   = drm_atomic_helper_crtc_destroy_state,
        .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
        .destroy                = apple_crtc_cleanup,
        .page_flip              = drm_atomic_helper_page_flip,
        .reset                  = drm_atomic_helper_crtc_reset,
        .set_config             = drm_atomic_helper_set_config,
};

static const struct drm_mode_config_funcs apple_mode_config_funcs = {
        .atomic_check           = drm_atomic_helper_check,
        .atomic_commit          = drm_atomic_helper_commit,
        .fb_create              = drm_gem_fb_create,
};

static const struct drm_mode_config_helper_funcs apple_mode_config_helpers = {
        .atomic_commit_tail     = dcp_atomic_commit_tail,
};

static void appledrm_connector_cleanup(struct drm_connector *connector)
{
        drm_connector_cleanup(connector);
        kfree(to_apple_connector(connector));
}

static const struct drm_connector_funcs apple_connector_funcs = {
        .fill_modes             = drm_helper_probe_single_connector_modes,
        .destroy                = appledrm_connector_cleanup,
        .reset                  = drm_atomic_helper_connector_reset,
        .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
        .atomic_destroy_state   = drm_atomic_helper_connector_destroy_state,
        .detect                 = apple_connector_detect,
};

static const struct drm_connector_helper_funcs apple_connector_helper_funcs = {
        .get_modes              = dcp_get_modes,
        .mode_valid             = dcp_mode_valid,
};

static const struct drm_crtc_helper_funcs apple_crtc_helper_funcs = {
        .atomic_begin           = apple_crtc_atomic_begin,
        .atomic_check           = dcp_crtc_atomic_check,
        .atomic_flush           = dcp_flush,
        .atomic_enable          = apple_crtc_atomic_enable,
        .atomic_disable         = apple_crtc_atomic_disable,
        .mode_fixup             = dcp_crtc_mode_fixup,
};

static int apple_probe_per_dcp(struct device *dev,
                               struct drm_device *drm,
                               struct platform_device *dcp,
                               int num, bool dcp_ext)
{
        struct apple_crtc *crtc;
        struct apple_connector *connector;
        struct apple_encoder *enc;
        struct drm_plane *primary;
        int ret;

        primary = apple_plane_init(drm, 1U << num, DRM_PLANE_TYPE_PRIMARY);

        if (IS_ERR(primary))
                return PTR_ERR(primary);

        crtc = kzalloc(sizeof(*crtc), GFP_KERNEL);
        ret = drm_crtc_init_with_planes(drm, &crtc->base, primary, NULL,
                                        &apple_crtc_funcs, NULL);
        if (ret)
                return ret;

        drm_crtc_helper_add(&crtc->base, &apple_crtc_helper_funcs);
        drm_crtc_enable_color_mgmt(&crtc->base, 0, true, 0);

        enc = drmm_simple_encoder_alloc(drm, struct apple_encoder, base,
                                        DRM_MODE_ENCODER_TMDS);
        if (IS_ERR(enc))
                return PTR_ERR(enc);
        enc->base.possible_crtcs = drm_crtc_mask(&crtc->base);

        connector = kzalloc(sizeof(*connector), GFP_KERNEL);
        drm_connector_helper_add(&connector->base,
                                 &apple_connector_helper_funcs);

#ifdef __linux__
        // HACK:
        if (dcp_ext)
                connector->base.fwnode = fwnode_handle_get(dev->fwnode);
#endif

        ret = drm_connector_init(drm, &connector->base, &apple_connector_funcs,
                                 dcp_get_connector_type(dcp));
        if (ret)
                return ret;

        connector->base.polled = DRM_CONNECTOR_POLL_HPD;
        connector->connected = false;
        connector->dcp = dcp;

        INIT_WORK(&connector->hotplug_wq, dcp_hotplug);

        crtc->dcp = dcp;
        dcp_link(dcp, crtc, connector);

        return drm_connector_attach_encoder(&connector->base, &enc->base);
}

static int apple_get_fb_resource(struct device *dev, const char *name,
                                 struct resource *fb_r)
{
        int idx, ret = -ENODEV;
        struct device_node *node;

        idx = of_property_match_string(dev->of_node, "memory-region-names", name);

        node = of_parse_phandle(dev->of_node, "memory-region", idx);
        if (!node) {
                dev_err(dev, "reserved-memory node '%s' not found\n", name);
                return -ENODEV;
        }

        if (!of_device_is_available(node)) {
                dev_err(dev, "reserved-memory node '%s' is unavailable\n", name);
                goto err;
        }

        if (!of_device_is_compatible(node, "framebuffer")) {
                dev_err(dev, "reserved-memory node '%s' is incompatible\n",
                        node->full_name);
                goto err;
        }

        ret = of_address_to_resource(node, 0, fb_r);

err:
        of_node_put(node);
        return ret;
}

static const struct of_device_id apple_dcp_id_tbl[] = {
        { .compatible = "apple,dcp" },
        { .compatible = "apple,dcpext" },
        {},
};

static int apple_drm_init_dcp(struct device *dev)
{
        struct apple_drm_private *apple = dev_get_drvdata(dev);
        struct platform_device *dcp[MAX_COPROCESSORS];
        struct device_node *np;
        u64 timeout;
        int i, ret, num_dcp = 0;

        for_each_matching_node(np, apple_dcp_id_tbl) {
                bool dcp_ext;
                if (!of_device_is_available(np)) {
                        of_node_put(np);
                        continue;
                }
                dcp_ext = of_device_is_compatible(np, "apple,dcpext");

                dcp[num_dcp] = of_find_device_by_node(np);
                of_node_put(np);
                if (!dcp[num_dcp])
                        continue;

                ret = apple_probe_per_dcp(dev, &apple->drm, dcp[num_dcp],
                                          num_dcp, dcp_ext);
                if (ret)
                        continue;

                ret = dcp_start(dcp[num_dcp]);
                if (ret)
                        continue;

                num_dcp++;
        }

        if (num_dcp < 1)
                return -ENODEV;

        /*
         * Starting DPTX might take some time.
         */
        timeout = get_jiffies_64() + msecs_to_jiffies(3000);

        for (i = 0; i < num_dcp; ++i) {
                u64 jiffies = get_jiffies_64();
                u64 wait = time_after_eq64(jiffies, timeout) ?
                                   0 :
                                   timeout - jiffies;
                ret = dcp_wait_ready(dcp[i], wait);
                /* There is nothing we can do if a dcp/dcpext does not boot
                 * (successfully). Ignoring it should not do any harm now.
                 * Needs to reevaluated when adding dcpext support.
                 */
                if (ret)
                        dev_warn(dev, "DCP[%d] not ready: %d\n", i, ret);
        }
        /* HACK: Wait for dcp* to settle before a modeset */
        drm_msleep(100);

        return 0;
}

static int apple_drm_init(struct device *dev)
{
        struct apple_drm_private *apple;
        struct resource fb_r;
        resource_size_t fb_size;
        int ret;

        ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(42));
        if (ret)
                return ret;

        ret = apple_get_fb_resource(dev, "framebuffer", &fb_r);
        if (ret)
                return ret;

        fb_size = fb_r.end - fb_r.start + 1;
        ret = aperture_remove_conflicting_devices(fb_r.start, fb_size,
                                                apple_drm_driver.name);
        if (ret) {
                dev_err(dev, "Failed remove fb: %d\n", ret);
                goto err_unbind;
        }

#ifdef __linux__
        apple = devm_drm_dev_alloc(dev, &apple_drm_driver,
                                   struct apple_drm_private, drm);
        if (IS_ERR(apple))
                return PTR_ERR(apple);
#else
        struct apldrm_softc *sc = (struct apldrm_softc *)dev;
        apple = (struct apple_drm_private *)&sc->sc_ddev;
#endif

        dev_set_drvdata(dev, apple);

        ret = component_bind_all(dev, apple);
        if (ret)
                return ret;

        ret = drmm_mode_config_init(&apple->drm);
        if (ret)
                goto err_unbind;

        /*
         * IOMFB::UPPipeDCP_H13P::verify_surfaces produces the error "plane
         * requires a minimum of 32x32 for the source buffer" if smaller
         */
        apple->drm.mode_config.min_width = 32;
        apple->drm.mode_config.min_height = 32;

        /*
         * TODO: this is the max framebuffer size not the maximal supported
         * output resolution. DCP reports the maximal framebuffer size take it
         * from there.
         * Hardcode it for now to the M1 Max DCP reported 'MaxSrcBufferWidth'
         * and 'MaxSrcBufferHeight' of 16384.
         */
        apple->drm.mode_config.max_width = 16384;
        apple->drm.mode_config.max_height = 16384;

        apple->drm.mode_config.funcs = &apple_mode_config_funcs;
        apple->drm.mode_config.helper_private = &apple_mode_config_helpers;

        ret = apple_drm_init_dcp(dev);
        if (ret)
                goto err_unbind;

        drm_mode_config_reset(&apple->drm);

        ret = drm_dev_register(&apple->drm, 0);
        if (ret)
                goto err_unbind;

        drm_client_setup_with_fourcc(&apple->drm, DRM_FORMAT_XRGB8888);

        return 0;

err_unbind:
        component_unbind_all(dev, NULL);
        return ret;
}

static void apple_drm_uninit(struct device *dev)
{
        struct apple_drm_private *apple = dev_get_drvdata(dev);

        drm_dev_unregister(&apple->drm);
        drm_atomic_helper_shutdown(&apple->drm);

        component_unbind_all(dev, NULL);

        dev_set_drvdata(dev, NULL);
}

static int apple_drm_bind(struct device *dev)
{
        return apple_drm_init(dev);
}

static void apple_drm_unbind(struct device *dev)
{
        apple_drm_uninit(dev);
}

const struct component_master_ops apple_drm_ops = {
        .bind   = apple_drm_bind,
        .unbind = apple_drm_unbind,
};

static int add_dcp_components(struct device *dev,
                              struct component_match **matchptr)
{
        struct device_node *np;
        int num = 0;

        for_each_matching_node(np, apple_dcp_id_tbl) {
                if (of_device_is_available(np)) {
                        drm_of_component_match_add(dev, matchptr,
                                                   component_compare_of, np);
                        num++;
                }
                of_node_put(np);
        }

        return num;
}

static int apple_platform_probe(struct platform_device *pdev)
{
        struct device *mdev = &pdev->dev;
        struct component_match *match = NULL;
        int num_dcp;

        /* add DCP components, handle less than 1 as probe error */
        num_dcp = add_dcp_components(mdev, &match);
        if (num_dcp < 1)
                return -ENODEV;

        return component_master_add_with_match(mdev, &apple_drm_ops, match);
}

#ifdef __linux__

static int apple_platform_remove(struct platform_device *pdev)
{
        component_master_del(&pdev->dev, &apple_drm_ops);

        return 0;
}

static const struct of_device_id of_match[] = {
        { .compatible = "apple,display-subsystem" },
        {}
};
MODULE_DEVICE_TABLE(of, of_match);

#endif

#ifdef CONFIG_PM_SLEEP
static int apple_platform_suspend(struct device *dev)
{
        struct apple_drm_private *apple = dev_get_drvdata(dev);

        if (apple)
                return drm_mode_config_helper_suspend(&apple->drm);

        return 0;
}

static int apple_platform_resume(struct device *dev)
{
        struct apple_drm_private *apple = dev_get_drvdata(dev);

        if (apple)
                drm_mode_config_helper_resume(&apple->drm);

        return 0;
}

static const struct dev_pm_ops apple_platform_pm_ops = {
        .suspend        = apple_platform_suspend,
        .resume         = apple_platform_resume,
};
#endif

#ifdef __linux__

static struct platform_driver apple_platform_driver = {
        .driver = {
                .name = "apple-drm",
                .of_match_table = of_match,
#ifdef CONFIG_PM_SLEEP
                .pm = &apple_platform_pm_ops,
#endif
        },
        .probe          = apple_platform_probe,
        .remove         = apple_platform_remove,
};

drm_module_platform_driver(apple_platform_driver);

MODULE_AUTHOR("Alyssa Rosenzweig <alyssa@rosenzweig.io>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("Dual MIT/GPL");

#endif