/*
 * drm kms/fb cma (contiguous memory allocator) helper functions
 *
 * Copyright (C) 2012 Analog Device Inc.
 *   Author: Lars-Peter Clausen <lars@metafoo.de>
 *
 * Based on udl_fbdev.c
 *  Copyright (C) 2012 Red Hat
 *
 * 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.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <drm/drmP.h>
#include <drm/drm_atomic.h>
#include <drm/drm_crtc.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_fb_cma_helper.h>
#include <linux/dma-buf.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <linux/reservation.h>

#define DEFAULT_FBDEFIO_DELAY_MS 50

struct drm_fb_cma {
        struct drm_framebuffer          fb;
        struct drm_gem_cma_object       *obj[4];
};

struct drm_fbdev_cma {
        struct drm_fb_helper    fb_helper;
        struct drm_fb_cma       *fb;
        const struct drm_framebuffer_funcs *fb_funcs;
};

/**
 * DOC: framebuffer cma helper functions
 *
 * Provides helper functions for creating a cma (contiguous memory allocator)
 * backed framebuffer.
 *
 * drm_fb_cma_create() is used in the &drm_mode_config_funcs.fb_create
 * callback function to create a cma backed framebuffer.
 *
 * An fbdev framebuffer backed by cma is also available by calling
 * drm_fbdev_cma_init(). drm_fbdev_cma_fini() tears it down.
 * If the &drm_framebuffer_funcs.dirty callback is set, fb_deferred_io will be
 * set up automatically. &drm_framebuffer_funcs.dirty is called by
 * drm_fb_helper_deferred_io() in process context (&struct delayed_work).
 *
 * Example fbdev deferred io code::
 *
 *     static int driver_fb_dirty(struct drm_framebuffer *fb,
 *                                struct drm_file *file_priv,
 *                                unsigned flags, unsigned color,
 *                                struct drm_clip_rect *clips,
 *                                unsigned num_clips)
 *     {
 *         struct drm_gem_cma_object *cma = drm_fb_cma_get_gem_obj(fb, 0);
 *         ... push changes ...
 *         return 0;
 *     }
 *
 *     static struct drm_framebuffer_funcs driver_fb_funcs = {
 *         .destroy       = drm_fb_cma_destroy,
 *         .create_handle = drm_fb_cma_create_handle,
 *         .dirty         = driver_fb_dirty,
 *     };
 *
 * Initialize::
 *
 *     fbdev = drm_fbdev_cma_init_with_funcs(dev, 16,
 *                                           dev->mode_config.num_crtc,
 *                                           dev->mode_config.num_connector,
 *                                           &driver_fb_funcs);
 *
 */

static inline struct drm_fbdev_cma *to_fbdev_cma(struct drm_fb_helper *helper)
{
        return container_of(helper, struct drm_fbdev_cma, fb_helper);
}

static inline struct drm_fb_cma *to_fb_cma(struct drm_framebuffer *fb)
{
        return container_of(fb, struct drm_fb_cma, fb);
}

void drm_fb_cma_destroy(struct drm_framebuffer *fb)
{
        struct drm_fb_cma *fb_cma = to_fb_cma(fb);
        int i;

        for (i = 0; i < 4; i++) {
                if (fb_cma->obj[i])
                        drm_gem_object_put_unlocked(&fb_cma->obj[i]->base);
        }

        drm_framebuffer_cleanup(fb);
        kfree(fb_cma);
}
EXPORT_SYMBOL(drm_fb_cma_destroy);

int drm_fb_cma_create_handle(struct drm_framebuffer *fb,
        struct drm_file *file_priv, unsigned int *handle)
{
        struct drm_fb_cma *fb_cma = to_fb_cma(fb);

        return drm_gem_handle_create(file_priv,
                        &fb_cma->obj[0]->base, handle);
}
EXPORT_SYMBOL(drm_fb_cma_create_handle);

static struct drm_framebuffer_funcs drm_fb_cma_funcs = {
        .destroy        = drm_fb_cma_destroy,
        .create_handle  = drm_fb_cma_create_handle,
};

static struct drm_fb_cma *drm_fb_cma_alloc(struct drm_device *dev,
        const struct drm_mode_fb_cmd2 *mode_cmd,
        struct drm_gem_cma_object **obj,
        unsigned int num_planes, const struct drm_framebuffer_funcs *funcs)
{
        struct drm_fb_cma *fb_cma;
        int ret;
        int i;

        fb_cma = kzalloc(sizeof(*fb_cma), GFP_KERNEL);
        if (!fb_cma)
                return ERR_PTR(-ENOMEM);

        drm_helper_mode_fill_fb_struct(dev, &fb_cma->fb, mode_cmd);

        for (i = 0; i < num_planes; i++)
                fb_cma->obj[i] = obj[i];

        ret = drm_framebuffer_init(dev, &fb_cma->fb, funcs);
        if (ret) {
                dev_err(dev->dev, "Failed to initialize framebuffer: %d\n", ret);
                kfree(fb_cma);
                return ERR_PTR(ret);
        }

        return fb_cma;
}

/**
 * drm_fb_cma_create_with_funcs() - helper function for the
 *                                  &drm_mode_config_funcs.fb_create
 *                                  callback
 * @dev: DRM device
 * @file_priv: drm file for the ioctl call
 * @mode_cmd: metadata from the userspace fb creation request
 * @funcs: vtable to be used for the new framebuffer object
 *
 * This can be used to set &drm_framebuffer_funcs for drivers that need the
 * &drm_framebuffer_funcs.dirty callback. Use drm_fb_cma_create() if you don't
 * need to change &drm_framebuffer_funcs.
 */
struct drm_framebuffer *drm_fb_cma_create_with_funcs(struct drm_device *dev,
        struct drm_file *file_priv, const struct drm_mode_fb_cmd2 *mode_cmd,
        const struct drm_framebuffer_funcs *funcs)
{
        const struct drm_format_info *info;
        struct drm_fb_cma *fb_cma;
        struct drm_gem_cma_object *objs[4];
        struct drm_gem_object *obj;
        int ret;
        int i;

        info = drm_get_format_info(dev, mode_cmd);
        if (!info)
                return ERR_PTR(-EINVAL);

        for (i = 0; i < info->num_planes; i++) {
                unsigned int width = mode_cmd->width / (i ? info->hsub : 1);
                unsigned int height = mode_cmd->height / (i ? info->vsub : 1);
                unsigned int min_size;

                obj = drm_gem_object_lookup(file_priv, mode_cmd->handles[i]);
                if (!obj) {
                        dev_err(dev->dev, "Failed to lookup GEM object\n");
                        ret = -ENXIO;
                        goto err_gem_object_put;
                }

                min_size = (height - 1) * mode_cmd->pitches[i]
                         + width * info->cpp[i]
                         + mode_cmd->offsets[i];

                if (obj->size < min_size) {
                        drm_gem_object_put_unlocked(obj);
                        ret = -EINVAL;
                        goto err_gem_object_put;
                }
                objs[i] = to_drm_gem_cma_obj(obj);
        }

        fb_cma = drm_fb_cma_alloc(dev, mode_cmd, objs, i, funcs);
        if (IS_ERR(fb_cma)) {
                ret = PTR_ERR(fb_cma);
                goto err_gem_object_put;
        }

        return &fb_cma->fb;

err_gem_object_put:
        for (i--; i >= 0; i--)
                drm_gem_object_put_unlocked(&objs[i]->base);
        return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(drm_fb_cma_create_with_funcs);

/**
 * drm_fb_cma_create() - &drm_mode_config_funcs.fb_create callback function
 * @dev: DRM device
 * @file_priv: drm file for the ioctl call
 * @mode_cmd: metadata from the userspace fb creation request
 *
 * If your hardware has special alignment or pitch requirements these should be
 * checked before calling this function. Use drm_fb_cma_create_with_funcs() if
 * you need to set &drm_framebuffer_funcs.dirty.
 */
struct drm_framebuffer *drm_fb_cma_create(struct drm_device *dev,
        struct drm_file *file_priv, const struct drm_mode_fb_cmd2 *mode_cmd)
{
        return drm_fb_cma_create_with_funcs(dev, file_priv, mode_cmd,
                                            &drm_fb_cma_funcs);
}
EXPORT_SYMBOL_GPL(drm_fb_cma_create);

/**
 * drm_fb_cma_get_gem_obj() - Get CMA GEM object for framebuffer
 * @fb: The framebuffer
 * @plane: Which plane
 *
 * Return the CMA GEM object for given framebuffer.
 *
 * This function will usually be called from the CRTC callback functions.
 */
struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
                                                  unsigned int plane)
{
        struct drm_fb_cma *fb_cma = to_fb_cma(fb);

        if (plane >= 4)
                return NULL;

        return fb_cma->obj[plane];
}
EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);

/**
 * drm_fb_cma_prepare_fb() - Prepare CMA framebuffer
 * @plane: Which plane
 * @state: Plane state attach fence to
 *
 * This should be set as the &struct drm_plane_helper_funcs.prepare_fb hook.
 *
 * This function checks if the plane FB has an dma-buf attached, extracts
 * the exclusive fence and attaches it to plane state for the atomic helper
 * to wait on.
 *
 * There is no need for cleanup_fb for CMA based framebuffer drivers.
 */
int drm_fb_cma_prepare_fb(struct drm_plane *plane,
                          struct drm_plane_state *state)
{
        struct dma_buf *dma_buf;
        struct dma_fence *fence;

        if ((plane->state->fb == state->fb) || !state->fb)
                return 0;

        dma_buf = drm_fb_cma_get_gem_obj(state->fb, 0)->base.dma_buf;
        if (dma_buf) {
                fence = reservation_object_get_excl_rcu(dma_buf->resv);
                drm_atomic_set_fence_for_plane(state, fence);
        }

        return 0;
}
EXPORT_SYMBOL_GPL(drm_fb_cma_prepare_fb);

#ifdef CONFIG_DEBUG_FS
static void drm_fb_cma_describe(struct drm_framebuffer *fb, struct seq_file *m)
{
        struct drm_fb_cma *fb_cma = to_fb_cma(fb);
        int i;

        seq_printf(m, "fb: %dx%d@%4.4s\n", fb->width, fb->height,
                        (char *)&fb->format->format);

        for (i = 0; i < fb->format->num_planes; i++) {
                seq_printf(m, "   %d: offset=%d pitch=%d, obj: ",
                                i, fb->offsets[i], fb->pitches[i]);
                drm_gem_cma_describe(fb_cma->obj[i], m);
        }
}

/**
 * drm_fb_cma_debugfs_show() - Helper to list CMA framebuffer objects
 *                             in debugfs.
 * @m: output file
 * @arg: private data for the callback
 */
int drm_fb_cma_debugfs_show(struct seq_file *m, void *arg)
{
        struct drm_info_node *node = (struct drm_info_node *) m->private;
        struct drm_device *dev = node->minor->dev;
        struct drm_framebuffer *fb;

        mutex_lock(&dev->mode_config.fb_lock);
        drm_for_each_fb(fb, dev)
                drm_fb_cma_describe(fb, m);
        mutex_unlock(&dev->mode_config.fb_lock);

        return 0;
}
EXPORT_SYMBOL_GPL(drm_fb_cma_debugfs_show);
#endif

static int drm_fb_cma_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
        return dma_mmap_writecombine(info->device, vma, info->screen_base,
                                     info->fix.smem_start, info->fix.smem_len);
}

static struct fb_ops drm_fbdev_cma_ops = {
        .owner          = THIS_MODULE,
        DRM_FB_HELPER_DEFAULT_OPS,
        .fb_fillrect    = drm_fb_helper_sys_fillrect,
        .fb_copyarea    = drm_fb_helper_sys_copyarea,
        .fb_imageblit   = drm_fb_helper_sys_imageblit,
        .fb_mmap        = drm_fb_cma_mmap,
};

static int drm_fbdev_cma_deferred_io_mmap(struct fb_info *info,
                                          struct vm_area_struct *vma)
{
        fb_deferred_io_mmap(info, vma);
        vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

        return 0;
}

static int drm_fbdev_cma_defio_init(struct fb_info *fbi,
                                    struct drm_gem_cma_object *cma_obj)
{
        struct fb_deferred_io *fbdefio;
        struct fb_ops *fbops;

        /*
         * Per device structures are needed because:
         * fbops: fb_deferred_io_cleanup() clears fbops.fb_mmap
         * fbdefio: individual delays
         */
        fbdefio = kzalloc(sizeof(*fbdefio), GFP_KERNEL);
        fbops = kzalloc(sizeof(*fbops), GFP_KERNEL);
        if (!fbdefio || !fbops) {
                kfree(fbdefio);
                kfree(fbops);
                return -ENOMEM;
        }

        /* can't be offset from vaddr since dirty() uses cma_obj */
        fbi->screen_buffer = cma_obj->vaddr;
        /* fb_deferred_io_fault() needs a physical address */
        fbi->fix.smem_start = page_to_phys(virt_to_page(fbi->screen_buffer));

        *fbops = *fbi->fbops;
        fbi->fbops = fbops;

        fbdefio->delay = msecs_to_jiffies(DEFAULT_FBDEFIO_DELAY_MS);
        fbdefio->deferred_io = drm_fb_helper_deferred_io;
        fbi->fbdefio = fbdefio;
        fb_deferred_io_init(fbi);
        fbi->fbops->fb_mmap = drm_fbdev_cma_deferred_io_mmap;

        return 0;
}

static void drm_fbdev_cma_defio_fini(struct fb_info *fbi)
{
        if (!fbi->fbdefio)
                return;

        fb_deferred_io_cleanup(fbi);
        kfree(fbi->fbdefio);
        kfree(fbi->fbops);
}

static int
drm_fbdev_cma_create(struct drm_fb_helper *helper,
        struct drm_fb_helper_surface_size *sizes)
{
        struct drm_fbdev_cma *fbdev_cma = to_fbdev_cma(helper);
        struct drm_mode_fb_cmd2 mode_cmd = { 0 };
        struct drm_device *dev = helper->dev;
        struct drm_gem_cma_object *obj;
        struct drm_framebuffer *fb;
        unsigned int bytes_per_pixel;
        unsigned long offset;
        struct fb_info *fbi;
        size_t size;
        int ret;

        DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d)\n",
                        sizes->surface_width, sizes->surface_height,
                        sizes->surface_bpp);

        bytes_per_pixel = DIV_ROUND_UP(sizes->surface_bpp, 8);

        mode_cmd.width = sizes->surface_width;
        mode_cmd.height = sizes->surface_height;
        mode_cmd.pitches[0] = sizes->surface_width * bytes_per_pixel;
        mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
                sizes->surface_depth);

        size = mode_cmd.pitches[0] * mode_cmd.height;
        obj = drm_gem_cma_create(dev, size);
        if (IS_ERR(obj))
                return -ENOMEM;

        fbi = drm_fb_helper_alloc_fbi(helper);
        if (IS_ERR(fbi)) {
                ret = PTR_ERR(fbi);
                goto err_gem_free_object;
        }

        fbdev_cma->fb = drm_fb_cma_alloc(dev, &mode_cmd, &obj, 1,
                                         fbdev_cma->fb_funcs);
        if (IS_ERR(fbdev_cma->fb)) {
                dev_err(dev->dev, "Failed to allocate DRM framebuffer.\n");
                ret = PTR_ERR(fbdev_cma->fb);
                goto err_fb_info_destroy;
        }

        fb = &fbdev_cma->fb->fb;
        helper->fb = fb;

        fbi->par = helper;
        fbi->flags = FBINFO_FLAG_DEFAULT;
        fbi->fbops = &drm_fbdev_cma_ops;

        drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->format->depth);
        drm_fb_helper_fill_var(fbi, helper, sizes->fb_width, sizes->fb_height);

        offset = fbi->var.xoffset * bytes_per_pixel;
        offset += fbi->var.yoffset * fb->pitches[0];

        dev->mode_config.fb_base = (resource_size_t)obj->paddr;
        fbi->screen_base = obj->vaddr + offset;
        fbi->fix.smem_start = (unsigned long)(obj->paddr + offset);
        fbi->screen_size = size;
        fbi->fix.smem_len = size;

        if (fbdev_cma->fb_funcs->dirty) {
                ret = drm_fbdev_cma_defio_init(fbi, obj);
                if (ret)
                        goto err_cma_destroy;
        }

        return 0;

err_cma_destroy:
        drm_framebuffer_remove(&fbdev_cma->fb->fb);
err_fb_info_destroy:
        drm_fb_helper_fini(helper);
err_gem_free_object:
        drm_gem_object_put_unlocked(&obj->base);
        return ret;
}

static const struct drm_fb_helper_funcs drm_fb_cma_helper_funcs = {
        .fb_probe = drm_fbdev_cma_create,
};

/**
 * drm_fbdev_cma_init_with_funcs() - Allocate and initializes a drm_fbdev_cma struct
 * @dev: DRM device
 * @preferred_bpp: Preferred bits per pixel for the device
 * @max_conn_count: Maximum number of connectors
 * @funcs: fb helper functions, in particular a custom dirty() callback
 *
 * Returns a newly allocated drm_fbdev_cma struct or a ERR_PTR.
 */
struct drm_fbdev_cma *drm_fbdev_cma_init_with_funcs(struct drm_device *dev,
        unsigned int preferred_bpp, unsigned int max_conn_count,
        const struct drm_framebuffer_funcs *funcs)
{
        struct drm_fbdev_cma *fbdev_cma;
        struct drm_fb_helper *helper;
        int ret;

        fbdev_cma = kzalloc(sizeof(*fbdev_cma), GFP_KERNEL);
        if (!fbdev_cma) {
                dev_err(dev->dev, "Failed to allocate drm fbdev.\n");
                return ERR_PTR(-ENOMEM);
        }
        fbdev_cma->fb_funcs = funcs;

        helper = &fbdev_cma->fb_helper;

        drm_fb_helper_prepare(dev, helper, &drm_fb_cma_helper_funcs);

        ret = drm_fb_helper_init(dev, helper, max_conn_count);
        if (ret < 0) {
                dev_err(dev->dev, "Failed to initialize drm fb helper.\n");
                goto err_free;
        }

        ret = drm_fb_helper_single_add_all_connectors(helper);
        if (ret < 0) {
                dev_err(dev->dev, "Failed to add connectors.\n");
                goto err_drm_fb_helper_fini;

        }

        ret = drm_fb_helper_initial_config(helper, preferred_bpp);
        if (ret < 0) {
                dev_err(dev->dev, "Failed to set initial hw configuration.\n");
                goto err_drm_fb_helper_fini;
        }

        return fbdev_cma;

err_drm_fb_helper_fini:
        drm_fb_helper_fini(helper);
err_free:
        kfree(fbdev_cma);

        return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_init_with_funcs);

/**
 * drm_fbdev_cma_init() - Allocate and initializes a drm_fbdev_cma struct
 * @dev: DRM device
 * @preferred_bpp: Preferred bits per pixel for the device
 * @max_conn_count: Maximum number of connectors
 *
 * Returns a newly allocated drm_fbdev_cma struct or a ERR_PTR.
 */
struct drm_fbdev_cma *drm_fbdev_cma_init(struct drm_device *dev,
        unsigned int preferred_bpp, unsigned int max_conn_count)
{
        return drm_fbdev_cma_init_with_funcs(dev, preferred_bpp,
                                             max_conn_count,
                                             &drm_fb_cma_funcs);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_init);

/**
 * drm_fbdev_cma_fini() - Free drm_fbdev_cma struct
 * @fbdev_cma: The drm_fbdev_cma struct
 */
void drm_fbdev_cma_fini(struct drm_fbdev_cma *fbdev_cma)
{
        drm_fb_helper_unregister_fbi(&fbdev_cma->fb_helper);
        if (fbdev_cma->fb_helper.fbdev)
                drm_fbdev_cma_defio_fini(fbdev_cma->fb_helper.fbdev);

        if (fbdev_cma->fb)
                drm_framebuffer_remove(&fbdev_cma->fb->fb);

        drm_fb_helper_fini(&fbdev_cma->fb_helper);
        kfree(fbdev_cma);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_fini);

/**
 * drm_fbdev_cma_restore_mode() - Restores initial framebuffer mode
 * @fbdev_cma: The drm_fbdev_cma struct, may be NULL
 *
 * This function is usually called from the &drm_driver.lastclose callback.
 */
void drm_fbdev_cma_restore_mode(struct drm_fbdev_cma *fbdev_cma)
{
        if (fbdev_cma)
                drm_fb_helper_restore_fbdev_mode_unlocked(&fbdev_cma->fb_helper);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_restore_mode);

/**
 * drm_fbdev_cma_hotplug_event() - Poll for hotpulug events
 * @fbdev_cma: The drm_fbdev_cma struct, may be NULL
 *
 * This function is usually called from the &drm_mode_config.output_poll_changed
 * callback.
 */
void drm_fbdev_cma_hotplug_event(struct drm_fbdev_cma *fbdev_cma)
{
        if (fbdev_cma)
                drm_fb_helper_hotplug_event(&fbdev_cma->fb_helper);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_hotplug_event);

/**
 * drm_fbdev_cma_set_suspend - wrapper around drm_fb_helper_set_suspend
 * @fbdev_cma: The drm_fbdev_cma struct, may be NULL
 * @state: desired state, zero to resume, non-zero to suspend
 *
 * Calls drm_fb_helper_set_suspend, which is a wrapper around
 * fb_set_suspend implemented by fbdev core.
 */
void drm_fbdev_cma_set_suspend(struct drm_fbdev_cma *fbdev_cma, int state)
{
        if (fbdev_cma)
                drm_fb_helper_set_suspend(&fbdev_cma->fb_helper, state);
}
EXPORT_SYMBOL(drm_fbdev_cma_set_suspend);

/**
 * drm_fbdev_cma_set_suspend_unlocked - wrapper around
 *                                      drm_fb_helper_set_suspend_unlocked
 * @fbdev_cma: The drm_fbdev_cma struct, may be NULL
 * @state: desired state, zero to resume, non-zero to suspend
 *
 * Calls drm_fb_helper_set_suspend, which is a wrapper around
 * fb_set_suspend implemented by fbdev core.
 */
void drm_fbdev_cma_set_suspend_unlocked(struct drm_fbdev_cma *fbdev_cma,
                                        int state)
{
        if (fbdev_cma)
                drm_fb_helper_set_suspend_unlocked(&fbdev_cma->fb_helper,
                                                   state);
}
EXPORT_SYMBOL(drm_fbdev_cma_set_suspend_unlocked);