/*
 * Copyright 2012 Red Hat
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License version 2. See the file COPYING in the main
 * directory of this archive for more details.
 *
 * Authors: Matthew Garrett
 *          Dave Airlie
 */
#include <drm/drmP.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>

#include "cirrus_drv.h"

static const struct drm_framebuffer_funcs cirrus_fb_funcs = {
        .create_handle = drm_gem_fb_create_handle,
        .destroy = drm_gem_fb_destroy,
};

int cirrus_framebuffer_init(struct drm_device *dev,
                            struct drm_framebuffer *gfb,
                            const struct drm_mode_fb_cmd2 *mode_cmd,
                            struct drm_gem_object *obj)
{
        int ret;

        drm_helper_mode_fill_fb_struct(dev, gfb, mode_cmd);
        gfb->obj[0] = obj;
        ret = drm_framebuffer_init(dev, gfb, &cirrus_fb_funcs);
        if (ret) {
                DRM_ERROR("drm_framebuffer_init failed: %d\n", ret);
                return ret;
        }
        return 0;
}

static struct drm_framebuffer *
cirrus_user_framebuffer_create(struct drm_device *dev,
                               struct drm_file *filp,
                               const struct drm_mode_fb_cmd2 *mode_cmd)
{
        struct cirrus_device *cdev = dev->dev_private;
        struct drm_gem_object *obj;
        struct drm_framebuffer *fb;
        u32 bpp;
        int ret;

        bpp = drm_format_plane_cpp(mode_cmd->pixel_format, 0) * 8;

        if (!cirrus_check_framebuffer(cdev, mode_cmd->width, mode_cmd->height,
                                      bpp, mode_cmd->pitches[0]))
                return ERR_PTR(-EINVAL);

        obj = drm_gem_object_lookup(filp, mode_cmd->handles[0]);
        if (obj == NULL)
                return ERR_PTR(-ENOENT);

        fb = kzalloc(sizeof(*fb), GFP_KERNEL);
        if (!fb) {
                drm_gem_object_put_unlocked(obj);
                return ERR_PTR(-ENOMEM);
        }

        ret = cirrus_framebuffer_init(dev, fb, mode_cmd, obj);
        if (ret) {
                drm_gem_object_put_unlocked(obj);
                kfree(fb);
                return ERR_PTR(ret);
        }
        return fb;
}

static const struct drm_mode_config_funcs cirrus_mode_funcs = {
        .fb_create = cirrus_user_framebuffer_create,
};

/* Unmap the framebuffer from the core and release the memory */
static void cirrus_vram_fini(struct cirrus_device *cdev)
{
        iounmap(cdev->rmmio);
        cdev->rmmio = NULL;
        if (cdev->mc.vram_base)
                release_mem_region(cdev->mc.vram_base, cdev->mc.vram_size);
}

/* Map the framebuffer from the card and configure the core */
static int cirrus_vram_init(struct cirrus_device *cdev)
{
        /* BAR 0 is VRAM */
        cdev->mc.vram_base = pci_resource_start(cdev->dev->pdev, 0);
        cdev->mc.vram_size = pci_resource_len(cdev->dev->pdev, 0);

        if (!request_mem_region(cdev->mc.vram_base, cdev->mc.vram_size,
                                "cirrusdrmfb_vram")) {
                DRM_ERROR("can't reserve VRAM\n");
                return -ENXIO;
        }

        return 0;
}

/*
 * Our emulated hardware has two sets of memory. One is video RAM and can
 * simply be used as a linear framebuffer - the other provides mmio access
 * to the display registers. The latter can also be accessed via IO port
 * access, but we map the range and use mmio to program them instead
 */

int cirrus_device_init(struct cirrus_device *cdev,
                       struct drm_device *ddev,
                       struct pci_dev *pdev, uint32_t flags)
{
        int ret;

        cdev->dev = ddev;
        cdev->flags = flags;

        /* Hardcode the number of CRTCs to 1 */
        cdev->num_crtc = 1;

        /* BAR 0 is the framebuffer, BAR 1 contains registers */
        cdev->rmmio_base = pci_resource_start(cdev->dev->pdev, 1);
        cdev->rmmio_size = pci_resource_len(cdev->dev->pdev, 1);

        if (!request_mem_region(cdev->rmmio_base, cdev->rmmio_size,
                                "cirrusdrmfb_mmio")) {
                DRM_ERROR("can't reserve mmio registers\n");
                return -ENOMEM;
        }

        cdev->rmmio = ioremap(cdev->rmmio_base, cdev->rmmio_size);

        if (cdev->rmmio == NULL)
                return -ENOMEM;

        ret = cirrus_vram_init(cdev);
        if (ret) {
                release_mem_region(cdev->rmmio_base, cdev->rmmio_size);
                return ret;
        }

        return 0;
}

void cirrus_device_fini(struct cirrus_device *cdev)
{
        release_mem_region(cdev->rmmio_base, cdev->rmmio_size);
        cirrus_vram_fini(cdev);
}

/*
 * Functions here will be called by the core once it's bound the driver to
 * a PCI device
 */

int cirrus_driver_load(struct drm_device *dev, unsigned long flags)
{
        struct cirrus_device *cdev;
        int r;

        cdev = kzalloc(sizeof(struct cirrus_device), GFP_KERNEL);
        if (cdev == NULL)
                return -ENOMEM;
        dev->dev_private = (void *)cdev;

        r = cirrus_device_init(cdev, dev, dev->pdev, flags);
        if (r) {
                dev_err(&dev->pdev->dev, "Fatal error during GPU init: %d\n", r);
                goto out;
        }

        r = cirrus_mm_init(cdev);
        if (r) {
                dev_err(&dev->pdev->dev, "fatal err on mm init\n");
                goto out;
        }

        /*
         * cirrus_modeset_init() is initializing/registering the emulated fbdev
         * and DRM internals can access/test some of the fields in
         * mode_config->funcs as part of the fbdev registration process.
         * Make sure dev->mode_config.funcs is properly set to avoid
         * dereferencing a NULL pointer.
         * FIXME: mode_config.funcs assignment should probably be done in
         * cirrus_modeset_init() (that's a common pattern seen in other DRM
         * drivers).
         */
        dev->mode_config.funcs = &cirrus_mode_funcs;
        r = cirrus_modeset_init(cdev);
        if (r) {
                dev_err(&dev->pdev->dev, "Fatal error during modeset init: %d\n", r);
                goto out;
        }

        return 0;
out:
        cirrus_driver_unload(dev);
        return r;
}

void cirrus_driver_unload(struct drm_device *dev)
{
        struct cirrus_device *cdev = dev->dev_private;

        if (cdev == NULL)
                return;
        cirrus_modeset_fini(cdev);
        cirrus_mm_fini(cdev);
        cirrus_device_fini(cdev);
        kfree(cdev);
        dev->dev_private = NULL;
}

int cirrus_gem_create(struct drm_device *dev,
                   u32 size, bool iskernel,
                   struct drm_gem_object **obj)
{
        struct cirrus_bo *cirrusbo;
        int ret;

        *obj = NULL;

        size = roundup(size, PAGE_SIZE);
        if (size == 0)
                return -EINVAL;

        ret = cirrus_bo_create(dev, size, 0, 0, &cirrusbo);
        if (ret) {
                if (ret != -ERESTARTSYS)
                        DRM_ERROR("failed to allocate GEM object\n");
                return ret;
        }
        *obj = &cirrusbo->gem;
        return 0;
}

int cirrus_dumb_create(struct drm_file *file,
                    struct drm_device *dev,
                    struct drm_mode_create_dumb *args)
{
        int ret;
        struct drm_gem_object *gobj;
        u32 handle;

        args->pitch = args->width * ((args->bpp + 7) / 8);
        args->size = args->pitch * args->height;

        ret = cirrus_gem_create(dev, args->size, false,
                             &gobj);
        if (ret)
                return ret;

        ret = drm_gem_handle_create(file, gobj, &handle);
        drm_gem_object_put_unlocked(gobj);
        if (ret)
                return ret;

        args->handle = handle;
        return 0;
}

static void cirrus_bo_unref(struct cirrus_bo **bo)
{
        struct ttm_buffer_object *tbo;

        if ((*bo) == NULL)
                return;

        tbo = &((*bo)->bo);
        ttm_bo_put(tbo);
        *bo = NULL;
}

void cirrus_gem_free_object(struct drm_gem_object *obj)
{
        struct cirrus_bo *cirrus_bo = gem_to_cirrus_bo(obj);

        cirrus_bo_unref(&cirrus_bo);
}


static inline u64 cirrus_bo_mmap_offset(struct cirrus_bo *bo)
{
        return drm_vma_node_offset_addr(&bo->bo.vma_node);
}

int
cirrus_dumb_mmap_offset(struct drm_file *file,
                     struct drm_device *dev,
                     uint32_t handle,
                     uint64_t *offset)
{
        struct drm_gem_object *obj;
        struct cirrus_bo *bo;

        obj = drm_gem_object_lookup(file, handle);
        if (obj == NULL)
                return -ENOENT;

        bo = gem_to_cirrus_bo(obj);
        *offset = cirrus_bo_mmap_offset(bo);

        drm_gem_object_put_unlocked(obj);

        return 0;
}

bool cirrus_check_framebuffer(struct cirrus_device *cdev, int width, int height,
                              int bpp, int pitch)
{
        const int max_pitch = 0x1FF << 3; /* (4096 - 1) & ~111b bytes */
        const int max_size = cdev->mc.vram_size;

        if (bpp > cirrus_bpp)
                return false;
        if (bpp > 32)
                return false;

        if (pitch > max_pitch)
                return false;

        if (pitch * height > max_size)
                return false;

        return true;
}