/* exynos_drm_vidi.c
 *
 * Copyright (C) 2012 Samsung Electronics Co.Ltd
 * Authors:
 *      Inki Dae <inki.dae@samsung.com>
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 */
#include <drm/drmP.h>

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#include <drm/exynos_drm.h>

#include <drm/drm_edid.h>
#include <drm/drm_crtc_helper.h>

#include "exynos_drm_drv.h"
#include "exynos_drm_crtc.h"
#include "exynos_drm_encoder.h"

/* vidi has totally three virtual windows. */
#define WINDOWS_NR              3

#define get_vidi_context(dev)   platform_get_drvdata(to_platform_device(dev))

struct vidi_win_data {
        unsigned int            offset_x;
        unsigned int            offset_y;
        unsigned int            ovl_width;
        unsigned int            ovl_height;
        unsigned int            fb_width;
        unsigned int            fb_height;
        unsigned int            bpp;
        dma_addr_t              dma_addr;
        unsigned int            buf_offsize;
        unsigned int            line_size;      /* bytes */
        bool                    enabled;
};

struct vidi_context {
        struct exynos_drm_subdrv        subdrv;
        struct drm_crtc                 *crtc;
        struct vidi_win_data            win_data[WINDOWS_NR];
        struct edid                     *raw_edid;
        unsigned int                    clkdiv;
        unsigned int                    default_win;
        unsigned long                   irq_flags;
        unsigned int                    connected;
        bool                            vblank_on;
        bool                            suspended;
        bool                            direct_vblank;
        struct work_struct              work;
        struct mutex                    lock;
};

static const char fake_edid_info[] = {
        0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x4c, 0x2d, 0x05, 0x05,
        0x00, 0x00, 0x00, 0x00, 0x30, 0x12, 0x01, 0x03, 0x80, 0x10, 0x09, 0x78,
        0x0a, 0xee, 0x91, 0xa3, 0x54, 0x4c, 0x99, 0x26, 0x0f, 0x50, 0x54, 0xbd,
        0xee, 0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
        0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x66, 0x21, 0x50, 0xb0, 0x51, 0x00,
        0x1b, 0x30, 0x40, 0x70, 0x36, 0x00, 0xa0, 0x5a, 0x00, 0x00, 0x00, 0x1e,
        0x01, 0x1d, 0x00, 0x72, 0x51, 0xd0, 0x1e, 0x20, 0x6e, 0x28, 0x55, 0x00,
        0xa0, 0x5a, 0x00, 0x00, 0x00, 0x1e, 0x00, 0x00, 0x00, 0xfd, 0x00, 0x18,
        0x4b, 0x1a, 0x44, 0x17, 0x00, 0x0a, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
        0x00, 0x00, 0x00, 0xfc, 0x00, 0x53, 0x41, 0x4d, 0x53, 0x55, 0x4e, 0x47,
        0x0a, 0x20, 0x20, 0x20, 0x20, 0x20, 0x01, 0xbc, 0x02, 0x03, 0x1e, 0xf1,
        0x46, 0x84, 0x05, 0x03, 0x10, 0x20, 0x22, 0x23, 0x09, 0x07, 0x07, 0x83,
        0x01, 0x00, 0x00, 0xe2, 0x00, 0x0f, 0x67, 0x03, 0x0c, 0x00, 0x10, 0x00,
        0xb8, 0x2d, 0x01, 0x1d, 0x80, 0x18, 0x71, 0x1c, 0x16, 0x20, 0x58, 0x2c,
        0x25, 0x00, 0xa0, 0x5a, 0x00, 0x00, 0x00, 0x9e, 0x8c, 0x0a, 0xd0, 0x8a,
        0x20, 0xe0, 0x2d, 0x10, 0x10, 0x3e, 0x96, 0x00, 0xa0, 0x5a, 0x00, 0x00,
        0x00, 0x18, 0x02, 0x3a, 0x80, 0x18, 0x71, 0x38, 0x2d, 0x40, 0x58, 0x2c,
        0x45, 0x00, 0xa0, 0x5a, 0x00, 0x00, 0x00, 0x1e, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x06
};

static bool vidi_display_is_connected(struct device *dev)
{
        struct vidi_context *ctx = get_vidi_context(dev);

        DRM_DEBUG_KMS("%s\n", __FILE__);

        /*
         * connection request would come from user side
         * to do hotplug through specific ioctl.
         */
        return ctx->connected ? true : false;
}

static struct edid *vidi_get_edid(struct device *dev,
                        struct drm_connector *connector)
{
        struct vidi_context *ctx = get_vidi_context(dev);
        struct edid *edid;
        int edid_len;

        DRM_DEBUG_KMS("%s\n", __FILE__);

        /*
         * the edid data comes from user side and it would be set
         * to ctx->raw_edid through specific ioctl.
         */
        if (!ctx->raw_edid) {
                DRM_DEBUG_KMS("raw_edid is null.\n");
                return ERR_PTR(-EFAULT);
        }

        edid_len = (1 + ctx->raw_edid->extensions) * EDID_LENGTH;
        edid = kmemdup(ctx->raw_edid, edid_len, GFP_KERNEL);
        if (!edid) {
                DRM_DEBUG_KMS("failed to allocate edid\n");
                return ERR_PTR(-ENOMEM);
        }

        return edid;
}

static void *vidi_get_panel(struct device *dev)
{
        DRM_DEBUG_KMS("%s\n", __FILE__);

        /* TODO. */

        return NULL;
}

static int vidi_check_timing(struct device *dev, void *timing)
{
        DRM_DEBUG_KMS("%s\n", __FILE__);

        /* TODO. */

        return 0;
}

static int vidi_display_power_on(struct device *dev, int mode)
{
        DRM_DEBUG_KMS("%s\n", __FILE__);

        /* TODO */

        return 0;
}

static struct exynos_drm_display_ops vidi_display_ops = {
        .type = EXYNOS_DISPLAY_TYPE_VIDI,
        .is_connected = vidi_display_is_connected,
        .get_edid = vidi_get_edid,
        .get_panel = vidi_get_panel,
        .check_timing = vidi_check_timing,
        .power_on = vidi_display_power_on,
};

static void vidi_dpms(struct device *subdrv_dev, int mode)
{
        struct vidi_context *ctx = get_vidi_context(subdrv_dev);

        DRM_DEBUG_KMS("%s, %d\n", __FILE__, mode);

        mutex_lock(&ctx->lock);

        switch (mode) {
        case DRM_MODE_DPMS_ON:
                /* TODO. */
                break;
        case DRM_MODE_DPMS_STANDBY:
        case DRM_MODE_DPMS_SUSPEND:
        case DRM_MODE_DPMS_OFF:
                /* TODO. */
                break;
        default:
                DRM_DEBUG_KMS("unspecified mode %d\n", mode);
                break;
        }

        mutex_unlock(&ctx->lock);
}

static void vidi_apply(struct device *subdrv_dev)
{
        struct vidi_context *ctx = get_vidi_context(subdrv_dev);
        struct exynos_drm_manager *mgr = ctx->subdrv.manager;
        struct exynos_drm_manager_ops *mgr_ops = mgr->ops;
        struct exynos_drm_overlay_ops *ovl_ops = mgr->overlay_ops;
        struct vidi_win_data *win_data;
        int i;

        DRM_DEBUG_KMS("%s\n", __FILE__);

        for (i = 0; i < WINDOWS_NR; i++) {
                win_data = &ctx->win_data[i];
                if (win_data->enabled && (ovl_ops && ovl_ops->commit))
                        ovl_ops->commit(subdrv_dev, i);
        }

        if (mgr_ops && mgr_ops->commit)
                mgr_ops->commit(subdrv_dev);
}

static void vidi_commit(struct device *dev)
{
        struct vidi_context *ctx = get_vidi_context(dev);

        DRM_DEBUG_KMS("%s\n", __FILE__);

        if (ctx->suspended)
                return;
}

static int vidi_enable_vblank(struct device *dev)
{
        struct vidi_context *ctx = get_vidi_context(dev);

        DRM_DEBUG_KMS("%s\n", __FILE__);

        if (ctx->suspended)
                return -EPERM;

        if (!test_and_set_bit(0, &ctx->irq_flags))
                ctx->vblank_on = true;

        ctx->direct_vblank = true;

        /*
         * in case of page flip request, vidi_finish_pageflip function
         * will not be called because direct_vblank is true and then
         * that function will be called by overlay_ops->commit callback
         */
        schedule_work(&ctx->work);

        return 0;
}

static void vidi_disable_vblank(struct device *dev)
{
        struct vidi_context *ctx = get_vidi_context(dev);

        DRM_DEBUG_KMS("%s\n", __FILE__);

        if (ctx->suspended)
                return;

        if (test_and_clear_bit(0, &ctx->irq_flags))
                ctx->vblank_on = false;
}

static struct exynos_drm_manager_ops vidi_manager_ops = {
        .dpms = vidi_dpms,
        .apply = vidi_apply,
        .commit = vidi_commit,
        .enable_vblank = vidi_enable_vblank,
        .disable_vblank = vidi_disable_vblank,
};

static void vidi_win_mode_set(struct device *dev,
                              struct exynos_drm_overlay *overlay)
{
        struct vidi_context *ctx = get_vidi_context(dev);
        struct vidi_win_data *win_data;
        int win;
        unsigned long offset;

        DRM_DEBUG_KMS("%s\n", __FILE__);

        if (!overlay) {
                dev_err(dev, "overlay is NULL\n");
                return;
        }

        win = overlay->zpos;
        if (win == DEFAULT_ZPOS)
                win = ctx->default_win;

        if (win < 0 || win > WINDOWS_NR)
                return;

        offset = overlay->fb_x * (overlay->bpp >> 3);
        offset += overlay->fb_y * overlay->pitch;

        DRM_DEBUG_KMS("offset = 0x%lx, pitch = %x\n", offset, overlay->pitch);

        win_data = &ctx->win_data[win];

        win_data->offset_x = overlay->crtc_x;
        win_data->offset_y = overlay->crtc_y;
        win_data->ovl_width = overlay->crtc_width;
        win_data->ovl_height = overlay->crtc_height;
        win_data->fb_width = overlay->fb_width;
        win_data->fb_height = overlay->fb_height;
        win_data->dma_addr = overlay->dma_addr[0] + offset;
        win_data->bpp = overlay->bpp;
        win_data->buf_offsize = (overlay->fb_width - overlay->crtc_width) *
                                (overlay->bpp >> 3);
        win_data->line_size = overlay->crtc_width * (overlay->bpp >> 3);

        /*
         * some parts of win_data should be transferred to user side
         * through specific ioctl.
         */

        DRM_DEBUG_KMS("offset_x = %d, offset_y = %d\n",
                        win_data->offset_x, win_data->offset_y);
        DRM_DEBUG_KMS("ovl_width = %d, ovl_height = %d\n",
                        win_data->ovl_width, win_data->ovl_height);
        DRM_DEBUG_KMS("paddr = 0x%lx\n", (unsigned long)win_data->dma_addr);
        DRM_DEBUG_KMS("fb_width = %d, crtc_width = %d\n",
                        overlay->fb_width, overlay->crtc_width);
}

static void vidi_win_commit(struct device *dev, int zpos)
{
        struct vidi_context *ctx = get_vidi_context(dev);
        struct vidi_win_data *win_data;
        int win = zpos;

        DRM_DEBUG_KMS("%s\n", __FILE__);

        if (ctx->suspended)
                return;

        if (win == DEFAULT_ZPOS)
                win = ctx->default_win;

        if (win < 0 || win > WINDOWS_NR)
                return;

        win_data = &ctx->win_data[win];

        win_data->enabled = true;

        DRM_DEBUG_KMS("dma_addr = 0x%x\n", win_data->dma_addr);

        if (ctx->vblank_on)
                schedule_work(&ctx->work);
}

static void vidi_win_disable(struct device *dev, int zpos)
{
        struct vidi_context *ctx = get_vidi_context(dev);
        struct vidi_win_data *win_data;
        int win = zpos;

        DRM_DEBUG_KMS("%s\n", __FILE__);

        if (win == DEFAULT_ZPOS)
                win = ctx->default_win;

        if (win < 0 || win > WINDOWS_NR)
                return;

        win_data = &ctx->win_data[win];
        win_data->enabled = false;

        /* TODO. */
}

static struct exynos_drm_overlay_ops vidi_overlay_ops = {
        .mode_set = vidi_win_mode_set,
        .commit = vidi_win_commit,
        .disable = vidi_win_disable,
};

static struct exynos_drm_manager vidi_manager = {
        .pipe           = -1,
        .ops            = &vidi_manager_ops,
        .overlay_ops    = &vidi_overlay_ops,
        .display_ops    = &vidi_display_ops,
};

static void vidi_fake_vblank_handler(struct work_struct *work)
{
        struct vidi_context *ctx = container_of(work, struct vidi_context,
                                        work);
        struct exynos_drm_subdrv *subdrv = &ctx->subdrv;
        struct exynos_drm_manager *manager = subdrv->manager;

        if (manager->pipe < 0)
                return;

        /* refresh rate is about 50Hz. */
        usleep_range(16000, 20000);

        mutex_lock(&ctx->lock);

        if (ctx->direct_vblank) {
                drm_handle_vblank(subdrv->drm_dev, manager->pipe);
                ctx->direct_vblank = false;
                mutex_unlock(&ctx->lock);
                return;
        }

        mutex_unlock(&ctx->lock);

        exynos_drm_crtc_finish_pageflip(subdrv->drm_dev, manager->pipe);
}

static int vidi_subdrv_probe(struct drm_device *drm_dev, struct device *dev)
{
        DRM_DEBUG_KMS("%s\n", __FILE__);

        /*
         * enable drm irq mode.
         * - with irq_enabled = 1, we can use the vblank feature.
         *
         * P.S. note that we wouldn't use drm irq handler but
         *      just specific driver own one instead because
         *      drm framework supports only one irq handler.
         */
        drm_dev->irq_enabled = 1;

        /*
         * with vblank_disable_allowed = 1, vblank interrupt will be disabled
         * by drm timer once a current process gives up ownership of
         * vblank event.(after drm_vblank_put function is called)
         */
        drm_dev->vblank_disable_allowed = 1;

        return 0;
}

static void vidi_subdrv_remove(struct drm_device *drm_dev, struct device *dev)
{
        DRM_DEBUG_KMS("%s\n", __FILE__);

        /* TODO. */
}

static int vidi_power_on(struct vidi_context *ctx, bool enable)
{
        struct exynos_drm_subdrv *subdrv = &ctx->subdrv;
        struct device *dev = subdrv->dev;

        DRM_DEBUG_KMS("%s\n", __FILE__);

        if (enable != false && enable != true)
                return -EINVAL;

        if (enable) {
                ctx->suspended = false;

                /* if vblank was enabled status, enable it again. */
                if (test_and_clear_bit(0, &ctx->irq_flags))
                        vidi_enable_vblank(dev);

                vidi_apply(dev);
        } else {
                ctx->suspended = true;
        }

        return 0;
}

static int vidi_show_connection(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        int rc;
        struct vidi_context *ctx = get_vidi_context(dev);

        mutex_lock(&ctx->lock);

        rc = sprintf(buf, "%d\n", ctx->connected);

        mutex_unlock(&ctx->lock);

        return rc;
}

static int vidi_store_connection(struct device *dev,
                                struct device_attribute *attr,
                                const char *buf, size_t len)
{
        struct vidi_context *ctx = get_vidi_context(dev);
        int ret;

        DRM_DEBUG_KMS("%s\n", __FILE__);

        ret = kstrtoint(buf, 0, &ctx->connected);
        if (ret)
                return ret;

        if (ctx->connected > 1)
                return -EINVAL;

        /* use fake edid data for test. */
        if (!ctx->raw_edid)
                ctx->raw_edid = (struct edid *)fake_edid_info;

        /* if raw_edid isn't same as fake data then it can't be tested. */
        if (ctx->raw_edid != (struct edid *)fake_edid_info) {
                DRM_DEBUG_KMS("edid data is not fake data.\n");
                return -EINVAL;
        }

        DRM_DEBUG_KMS("requested connection.\n");

        drm_helper_hpd_irq_event(ctx->subdrv.drm_dev);

        return len;
}

static DEVICE_ATTR(connection, 0644, vidi_show_connection,
                        vidi_store_connection);

int vidi_connection_ioctl(struct drm_device *drm_dev, void *data,
                                struct drm_file *file_priv)
{
        struct vidi_context *ctx = NULL;
        struct drm_encoder *encoder;
        struct exynos_drm_manager *manager;
        struct exynos_drm_display_ops *display_ops;
        struct drm_exynos_vidi_connection *vidi = data;
        int edid_len;

        DRM_DEBUG_KMS("%s\n", __FILE__);

        if (!vidi) {
                DRM_DEBUG_KMS("user data for vidi is null.\n");
                return -EINVAL;
        }

        if (vidi->connection > 1) {
                DRM_DEBUG_KMS("connection should be 0 or 1.\n");
                return -EINVAL;
        }

        list_for_each_entry(encoder, &drm_dev->mode_config.encoder_list,
                                                                head) {
                manager = exynos_drm_get_manager(encoder);
                display_ops = manager->display_ops;

                if (display_ops->type == EXYNOS_DISPLAY_TYPE_VIDI) {
                        ctx = get_vidi_context(manager->dev);
                        break;
                }
        }

        if (!ctx) {
                DRM_DEBUG_KMS("not found virtual device type encoder.\n");
                return -EINVAL;
        }

        if (ctx->connected == vidi->connection) {
                DRM_DEBUG_KMS("same connection request.\n");
                return -EINVAL;
        }

        if (vidi->connection) {
                struct edid *raw_edid  = (struct edid *)(uint32_t)vidi->edid;
                if (!drm_edid_is_valid(raw_edid)) {
                        DRM_DEBUG_KMS("edid data is invalid.\n");
                        return -EINVAL;
                }
                edid_len = (1 + raw_edid->extensions) * EDID_LENGTH;
                ctx->raw_edid = kmemdup(raw_edid, edid_len, GFP_KERNEL);
                if (!ctx->raw_edid) {
                        DRM_DEBUG_KMS("failed to allocate raw_edid.\n");
                        return -ENOMEM;
                }
        } else {
                /*
                 * with connection = 0, free raw_edid
                 * only if raw edid data isn't same as fake data.
                 */
                if (ctx->raw_edid && ctx->raw_edid !=
                                (struct edid *)fake_edid_info) {
                        kfree(ctx->raw_edid);
                        ctx->raw_edid = NULL;
                }
        }

        ctx->connected = vidi->connection;
        drm_helper_hpd_irq_event(ctx->subdrv.drm_dev);

        return 0;
}

static int vidi_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct vidi_context *ctx;
        struct exynos_drm_subdrv *subdrv;
        int ret;

        DRM_DEBUG_KMS("%s\n", __FILE__);

        ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
        if (!ctx)
                return -ENOMEM;

        ctx->default_win = 0;

        INIT_WORK(&ctx->work, vidi_fake_vblank_handler);

        subdrv = &ctx->subdrv;
        subdrv->dev = dev;
        subdrv->manager = &vidi_manager;
        subdrv->probe = vidi_subdrv_probe;
        subdrv->remove = vidi_subdrv_remove;

        mutex_init(&ctx->lock);

        platform_set_drvdata(pdev, ctx);

        ret = device_create_file(dev, &dev_attr_connection);
        if (ret < 0)
                DRM_INFO("failed to create connection sysfs.\n");

        exynos_drm_subdrv_register(subdrv);

        return 0;
}

static int vidi_remove(struct platform_device *pdev)
{
        struct vidi_context *ctx = platform_get_drvdata(pdev);

        DRM_DEBUG_KMS("%s\n", __FILE__);

        exynos_drm_subdrv_unregister(&ctx->subdrv);

        if (ctx->raw_edid != (struct edid *)fake_edid_info) {
                kfree(ctx->raw_edid);
                ctx->raw_edid = NULL;
        }

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int vidi_suspend(struct device *dev)
{
        struct vidi_context *ctx = get_vidi_context(dev);

        return vidi_power_on(ctx, false);
}

static int vidi_resume(struct device *dev)
{
        struct vidi_context *ctx = get_vidi_context(dev);

        return vidi_power_on(ctx, true);
}
#endif

static const struct dev_pm_ops vidi_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(vidi_suspend, vidi_resume)
};

struct platform_driver vidi_driver = {
        .probe          = vidi_probe,
        .remove         = vidi_remove,
        .driver         = {
                .name   = "exynos-drm-vidi",
                .owner  = THIS_MODULE,
                .pm     = &vidi_pm_ops,
        },
};