/*
 * Copyright (C) Fuzhou Rockchip Electronics Co.Ltd
 * Author:Mark Yao <mark.yao@rock-chips.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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/drm.h>
#include <drm/drmP.h>
#include <drm/drm_gem.h>
#include <drm/drm_vma_manager.h>

#include <linux/dma-buf.h>
#include <linux/iommu.h>

#include "rockchip_drm_drv.h"
#include "rockchip_drm_gem.h"

static int rockchip_gem_iommu_map(struct rockchip_gem_object *rk_obj)
{
        struct drm_device *drm = rk_obj->base.dev;
        struct rockchip_drm_private *private = drm->dev_private;
        int prot = IOMMU_READ | IOMMU_WRITE;
        ssize_t ret;

        mutex_lock(&private->mm_lock);
        ret = drm_mm_insert_node_generic(&private->mm, &rk_obj->mm,
                                         rk_obj->base.size, PAGE_SIZE,
                                         0, 0);
        mutex_unlock(&private->mm_lock);

        if (ret < 0) {
                DRM_ERROR("out of I/O virtual memory: %zd\n", ret);
                return ret;
        }

        rk_obj->dma_addr = rk_obj->mm.start;

        ret = iommu_map_sg(private->domain, rk_obj->dma_addr, rk_obj->sgt->sgl,
                           rk_obj->sgt->nents, prot);
        if (ret < rk_obj->base.size) {
                DRM_ERROR("failed to map buffer: size=%zd request_size=%zd\n",
                          ret, rk_obj->base.size);
                ret = -ENOMEM;
                goto err_remove_node;
        }

        rk_obj->size = ret;

        return 0;

err_remove_node:
        mutex_lock(&private->mm_lock);
        drm_mm_remove_node(&rk_obj->mm);
        mutex_unlock(&private->mm_lock);

        return ret;
}

static int rockchip_gem_iommu_unmap(struct rockchip_gem_object *rk_obj)
{
        struct drm_device *drm = rk_obj->base.dev;
        struct rockchip_drm_private *private = drm->dev_private;

        iommu_unmap(private->domain, rk_obj->dma_addr, rk_obj->size);

        mutex_lock(&private->mm_lock);

        drm_mm_remove_node(&rk_obj->mm);

        mutex_unlock(&private->mm_lock);

        return 0;
}

static int rockchip_gem_get_pages(struct rockchip_gem_object *rk_obj)
{
        struct drm_device *drm = rk_obj->base.dev;
        int ret, i;
        struct scatterlist *s;

        rk_obj->pages = drm_gem_get_pages(&rk_obj->base);
        if (IS_ERR(rk_obj->pages))
                return PTR_ERR(rk_obj->pages);

        rk_obj->num_pages = rk_obj->base.size >> PAGE_SHIFT;

        rk_obj->sgt = drm_prime_pages_to_sg(rk_obj->pages, rk_obj->num_pages);
        if (IS_ERR(rk_obj->sgt)) {
                ret = PTR_ERR(rk_obj->sgt);
                goto err_put_pages;
        }

        /*
         * Fake up the SG table so that dma_sync_sg_for_device() can be used
         * to flush the pages associated with it.
         *
         * TODO: Replace this by drm_clflush_sg() once it can be implemented
         * without relying on symbols that are not exported.
         */
        for_each_sg(rk_obj->sgt->sgl, s, rk_obj->sgt->nents, i)
                sg_dma_address(s) = sg_phys(s);

        dma_sync_sg_for_device(drm->dev, rk_obj->sgt->sgl, rk_obj->sgt->nents,
                               DMA_TO_DEVICE);

        return 0;

err_put_pages:
        drm_gem_put_pages(&rk_obj->base, rk_obj->pages, false, false);
        return ret;
}

static void rockchip_gem_put_pages(struct rockchip_gem_object *rk_obj)
{
        sg_free_table(rk_obj->sgt);
        kfree(rk_obj->sgt);
        drm_gem_put_pages(&rk_obj->base, rk_obj->pages, true, true);
}

static int rockchip_gem_alloc_iommu(struct rockchip_gem_object *rk_obj,
                                    bool alloc_kmap)
{
        int ret;

        ret = rockchip_gem_get_pages(rk_obj);
        if (ret < 0)
                return ret;

        ret = rockchip_gem_iommu_map(rk_obj);
        if (ret < 0)
                goto err_free;

        if (alloc_kmap) {
                rk_obj->kvaddr = vmap(rk_obj->pages, rk_obj->num_pages, VM_MAP,
                                      pgprot_writecombine(PAGE_KERNEL));
                if (!rk_obj->kvaddr) {
                        DRM_ERROR("failed to vmap() buffer\n");
                        ret = -ENOMEM;
                        goto err_unmap;
                }
        }

        return 0;

err_unmap:
        rockchip_gem_iommu_unmap(rk_obj);
err_free:
        rockchip_gem_put_pages(rk_obj);

        return ret;
}

static int rockchip_gem_alloc_dma(struct rockchip_gem_object *rk_obj,
                                  bool alloc_kmap)
{
        struct drm_gem_object *obj = &rk_obj->base;
        struct drm_device *drm = obj->dev;

        rk_obj->dma_attrs = DMA_ATTR_WRITE_COMBINE;

        if (!alloc_kmap)
                rk_obj->dma_attrs |= DMA_ATTR_NO_KERNEL_MAPPING;

        rk_obj->kvaddr = dma_alloc_attrs(drm->dev, obj->size,
                                         &rk_obj->dma_addr, GFP_KERNEL,
                                         rk_obj->dma_attrs);
        if (!rk_obj->kvaddr) {
                DRM_ERROR("failed to allocate %zu byte dma buffer", obj->size);
                return -ENOMEM;
        }

        return 0;
}

static int rockchip_gem_alloc_buf(struct rockchip_gem_object *rk_obj,
                                  bool alloc_kmap)
{
        struct drm_gem_object *obj = &rk_obj->base;
        struct drm_device *drm = obj->dev;
        struct rockchip_drm_private *private = drm->dev_private;

        if (private->domain)
                return rockchip_gem_alloc_iommu(rk_obj, alloc_kmap);
        else
                return rockchip_gem_alloc_dma(rk_obj, alloc_kmap);
}

static void rockchip_gem_free_iommu(struct rockchip_gem_object *rk_obj)
{
        vunmap(rk_obj->kvaddr);
        rockchip_gem_iommu_unmap(rk_obj);
        rockchip_gem_put_pages(rk_obj);
}

static void rockchip_gem_free_dma(struct rockchip_gem_object *rk_obj)
{
        struct drm_gem_object *obj = &rk_obj->base;
        struct drm_device *drm = obj->dev;

        dma_free_attrs(drm->dev, obj->size, rk_obj->kvaddr, rk_obj->dma_addr,
                       rk_obj->dma_attrs);
}

static void rockchip_gem_free_buf(struct rockchip_gem_object *rk_obj)
{
        if (rk_obj->pages)
                rockchip_gem_free_iommu(rk_obj);
        else
                rockchip_gem_free_dma(rk_obj);
}

static int rockchip_drm_gem_object_mmap_iommu(struct drm_gem_object *obj,
                                              struct vm_area_struct *vma)
{
        struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
        unsigned int i, count = obj->size >> PAGE_SHIFT;
        unsigned long user_count = vma_pages(vma);
        unsigned long uaddr = vma->vm_start;
        unsigned long offset = vma->vm_pgoff;
        unsigned long end = user_count + offset;
        int ret;

        if (user_count == 0)
                return -ENXIO;
        if (end > count)
                return -ENXIO;

        for (i = offset; i < end; i++) {
                ret = vm_insert_page(vma, uaddr, rk_obj->pages[i]);
                if (ret)
                        return ret;
                uaddr += PAGE_SIZE;
        }

        return 0;
}

static int rockchip_drm_gem_object_mmap_dma(struct drm_gem_object *obj,
                                            struct vm_area_struct *vma)
{
        struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
        struct drm_device *drm = obj->dev;

        return dma_mmap_attrs(drm->dev, vma, rk_obj->kvaddr, rk_obj->dma_addr,
                              obj->size, rk_obj->dma_attrs);
}

static int rockchip_drm_gem_object_mmap(struct drm_gem_object *obj,
                                        struct vm_area_struct *vma)
{
        int ret;
        struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);

        /*
         * We allocated a struct page table for rk_obj, so clear
         * VM_PFNMAP flag that was set by drm_gem_mmap_obj()/drm_gem_mmap().
         */
        vma->vm_flags &= ~VM_PFNMAP;

        if (rk_obj->pages)
                ret = rockchip_drm_gem_object_mmap_iommu(obj, vma);
        else
                ret = rockchip_drm_gem_object_mmap_dma(obj, vma);

        if (ret)
                drm_gem_vm_close(vma);

        return ret;
}

int rockchip_gem_mmap_buf(struct drm_gem_object *obj,
                          struct vm_area_struct *vma)
{
        int ret;

        ret = drm_gem_mmap_obj(obj, obj->size, vma);
        if (ret)
                return ret;

        return rockchip_drm_gem_object_mmap(obj, vma);
}

/* drm driver mmap file operations */
int rockchip_gem_mmap(struct file *filp, struct vm_area_struct *vma)
{
        struct drm_gem_object *obj;
        int ret;

        ret = drm_gem_mmap(filp, vma);
        if (ret)
                return ret;

        /*
         * Set vm_pgoff (used as a fake buffer offset by DRM) to 0 and map the
         * whole buffer from the start.
         */
        vma->vm_pgoff = 0;

        obj = vma->vm_private_data;

        return rockchip_drm_gem_object_mmap(obj, vma);
}

static void rockchip_gem_release_object(struct rockchip_gem_object *rk_obj)
{
        drm_gem_object_release(&rk_obj->base);
        kfree(rk_obj);
}

struct rockchip_gem_object *
        rockchip_gem_alloc_object(struct drm_device *drm, unsigned int size)
{
        struct rockchip_gem_object *rk_obj;
        struct drm_gem_object *obj;

        size = round_up(size, PAGE_SIZE);

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

        obj = &rk_obj->base;

        drm_gem_object_init(drm, obj, size);

        return rk_obj;
}

struct rockchip_gem_object *
rockchip_gem_create_object(struct drm_device *drm, unsigned int size,
                           bool alloc_kmap)
{
        struct rockchip_gem_object *rk_obj;
        int ret;

        rk_obj = rockchip_gem_alloc_object(drm, size);
        if (IS_ERR(rk_obj))
                return rk_obj;

        ret = rockchip_gem_alloc_buf(rk_obj, alloc_kmap);
        if (ret)
                goto err_free_rk_obj;

        return rk_obj;

err_free_rk_obj:
        rockchip_gem_release_object(rk_obj);
        return ERR_PTR(ret);
}

/*
 * rockchip_gem_free_object - (struct drm_driver)->gem_free_object_unlocked
 * callback function
 */
void rockchip_gem_free_object(struct drm_gem_object *obj)
{
        struct drm_device *drm = obj->dev;
        struct rockchip_drm_private *private = drm->dev_private;
        struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);

        if (obj->import_attach) {
                if (private->domain) {
                        rockchip_gem_iommu_unmap(rk_obj);
                } else {
                        dma_unmap_sg(drm->dev, rk_obj->sgt->sgl,
                                     rk_obj->sgt->nents, DMA_BIDIRECTIONAL);
                }
                drm_prime_gem_destroy(obj, rk_obj->sgt);
        } else {
                rockchip_gem_free_buf(rk_obj);
        }

        rockchip_gem_release_object(rk_obj);
}

/*
 * rockchip_gem_create_with_handle - allocate an object with the given
 * size and create a gem handle on it
 *
 * returns a struct rockchip_gem_object* on success or ERR_PTR values
 * on failure.
 */
static struct rockchip_gem_object *
rockchip_gem_create_with_handle(struct drm_file *file_priv,
                                struct drm_device *drm, unsigned int size,
                                unsigned int *handle)
{
        struct rockchip_gem_object *rk_obj;
        struct drm_gem_object *obj;
        int ret;

        rk_obj = rockchip_gem_create_object(drm, size, false);
        if (IS_ERR(rk_obj))
                return ERR_CAST(rk_obj);

        obj = &rk_obj->base;

        /*
         * allocate a id of idr table where the obj is registered
         * and handle has the id what user can see.
         */
        ret = drm_gem_handle_create(file_priv, obj, handle);
        if (ret)
                goto err_handle_create;

        /* drop reference from allocate - handle holds it now. */
        drm_gem_object_put_unlocked(obj);

        return rk_obj;

err_handle_create:
        rockchip_gem_free_object(obj);

        return ERR_PTR(ret);
}

/*
 * rockchip_gem_dumb_create - (struct drm_driver)->dumb_create callback
 * function
 *
 * This aligns the pitch and size arguments to the minimum required. wrap
 * this into your own function if you need bigger alignment.
 */
int rockchip_gem_dumb_create(struct drm_file *file_priv,
                             struct drm_device *dev,
                             struct drm_mode_create_dumb *args)
{
        struct rockchip_gem_object *rk_obj;
        int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);

        /*
         * align to 64 bytes since Mali requires it.
         */
        args->pitch = ALIGN(min_pitch, 64);
        args->size = args->pitch * args->height;

        rk_obj = rockchip_gem_create_with_handle(file_priv, dev, args->size,
                                                 &args->handle);

        return PTR_ERR_OR_ZERO(rk_obj);
}

/*
 * Allocate a sg_table for this GEM object.
 * Note: Both the table's contents, and the sg_table itself must be freed by
 *       the caller.
 * Returns a pointer to the newly allocated sg_table, or an ERR_PTR() error.
 */
struct sg_table *rockchip_gem_prime_get_sg_table(struct drm_gem_object *obj)
{
        struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
        struct drm_device *drm = obj->dev;
        struct sg_table *sgt;
        int ret;

        if (rk_obj->pages)
                return drm_prime_pages_to_sg(rk_obj->pages, rk_obj->num_pages);

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

        ret = dma_get_sgtable_attrs(drm->dev, sgt, rk_obj->kvaddr,
                                    rk_obj->dma_addr, obj->size,
                                    rk_obj->dma_attrs);
        if (ret) {
                DRM_ERROR("failed to allocate sgt, %d\n", ret);
                kfree(sgt);
                return ERR_PTR(ret);
        }

        return sgt;
}

static unsigned long rockchip_sg_get_contiguous_size(struct sg_table *sgt,
                                                     int count)
{
        struct scatterlist *s;
        dma_addr_t expected = sg_dma_address(sgt->sgl);
        unsigned int i;
        unsigned long size = 0;

        for_each_sg(sgt->sgl, s, count, i) {
                if (sg_dma_address(s) != expected)
                        break;
                expected = sg_dma_address(s) + sg_dma_len(s);
                size += sg_dma_len(s);
        }
        return size;
}

static int
rockchip_gem_iommu_map_sg(struct drm_device *drm,
                          struct dma_buf_attachment *attach,
                          struct sg_table *sg,
                          struct rockchip_gem_object *rk_obj)
{
        rk_obj->sgt = sg;
        return rockchip_gem_iommu_map(rk_obj);
}

static int
rockchip_gem_dma_map_sg(struct drm_device *drm,
                        struct dma_buf_attachment *attach,
                        struct sg_table *sg,
                        struct rockchip_gem_object *rk_obj)
{
        int count = dma_map_sg(drm->dev, sg->sgl, sg->nents,
                               DMA_BIDIRECTIONAL);
        if (!count)
                return -EINVAL;

        if (rockchip_sg_get_contiguous_size(sg, count) < attach->dmabuf->size) {
                DRM_ERROR("failed to map sg_table to contiguous linear address.\n");
                dma_unmap_sg(drm->dev, sg->sgl, sg->nents,
                             DMA_BIDIRECTIONAL);
                return -EINVAL;
        }

        rk_obj->dma_addr = sg_dma_address(sg->sgl);
        rk_obj->sgt = sg;
        return 0;
}

struct drm_gem_object *
rockchip_gem_prime_import_sg_table(struct drm_device *drm,
                                   struct dma_buf_attachment *attach,
                                   struct sg_table *sg)
{
        struct rockchip_drm_private *private = drm->dev_private;
        struct rockchip_gem_object *rk_obj;
        int ret;

        rk_obj = rockchip_gem_alloc_object(drm, attach->dmabuf->size);
        if (IS_ERR(rk_obj))
                return ERR_CAST(rk_obj);

        if (private->domain)
                ret = rockchip_gem_iommu_map_sg(drm, attach, sg, rk_obj);
        else
                ret = rockchip_gem_dma_map_sg(drm, attach, sg, rk_obj);

        if (ret < 0) {
                DRM_ERROR("failed to import sg table: %d\n", ret);
                goto err_free_rk_obj;
        }

        return &rk_obj->base;

err_free_rk_obj:
        rockchip_gem_release_object(rk_obj);
        return ERR_PTR(ret);
}

void *rockchip_gem_prime_vmap(struct drm_gem_object *obj)
{
        struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);

        if (rk_obj->pages)
                return vmap(rk_obj->pages, rk_obj->num_pages, VM_MAP,
                            pgprot_writecombine(PAGE_KERNEL));

        if (rk_obj->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
                return NULL;

        return rk_obj->kvaddr;
}

void rockchip_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
{
        struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);

        if (rk_obj->pages) {
                vunmap(vaddr);
                return;
        }

        /* Nothing to do if allocated by DMA mapping API. */
}