// SPDX-License-Identifier: GPL-2.0-only
/*
 * NVIDIA Tegra DRM GEM helper functions
 *
 * Copyright (C) 2012 Sascha Hauer, Pengutronix
 * Copyright (C) 2013-2015 NVIDIA CORPORATION, All rights reserved.
 *
 * Based on the GEM/CMA helpers
 *
 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
 */

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

#include <drm/drm_drv.h>
#include <drm/drm_prime.h>
#include <drm/tegra_drm.h>

#include "drm.h"
#include "gem.h"

MODULE_IMPORT_NS(DMA_BUF);

static void tegra_bo_put(struct host1x_bo *bo)
{
        struct tegra_bo *obj = host1x_to_tegra_bo(bo);

        drm_gem_object_put(&obj->gem);
}

/* XXX move this into lib/scatterlist.c? */
static int sg_alloc_table_from_sg(struct sg_table *sgt, struct scatterlist *sg,
                                  unsigned int nents, gfp_t gfp_mask)
{
        struct scatterlist *dst;
        unsigned int i;
        int err;

        err = sg_alloc_table(sgt, nents, gfp_mask);
        if (err < 0)
                return err;

        dst = sgt->sgl;

        for (i = 0; i < nents; i++) {
                sg_set_page(dst, sg_page(sg), sg->length, 0);
                dst = sg_next(dst);
                sg = sg_next(sg);
        }

        return 0;
}

static struct sg_table *tegra_bo_pin(struct device *dev, struct host1x_bo *bo,
                                     dma_addr_t *phys)
{
        struct tegra_bo *obj = host1x_to_tegra_bo(bo);
        struct sg_table *sgt;
        int err;

        /*
         * If we've manually mapped the buffer object through the IOMMU, make
         * sure to return the IOVA address of our mapping.
         *
         * Similarly, for buffers that have been allocated by the DMA API the
         * physical address can be used for devices that are not attached to
         * an IOMMU. For these devices, callers must pass a valid pointer via
         * the @phys argument.
         *
         * Imported buffers were also already mapped at import time, so the
         * existing mapping can be reused.
         */
        if (phys) {
                *phys = obj->iova;
                return NULL;
        }

        /*
         * If we don't have a mapping for this buffer yet, return an SG table
         * so that host1x can do the mapping for us via the DMA API.
         */
        sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
        if (!sgt)
                return ERR_PTR(-ENOMEM);

        if (obj->pages) {
                /*
                 * If the buffer object was allocated from the explicit IOMMU
                 * API code paths, construct an SG table from the pages.
                 */
                err = sg_alloc_table_from_pages(sgt, obj->pages, obj->num_pages,
                                                0, obj->gem.size, GFP_KERNEL);
                if (err < 0)
                        goto free;
        } else if (obj->sgt) {
                /*
                 * If the buffer object already has an SG table but no pages
                 * were allocated for it, it means the buffer was imported and
                 * the SG table needs to be copied to avoid overwriting any
                 * other potential users of the original SG table.
                 */
                err = sg_alloc_table_from_sg(sgt, obj->sgt->sgl,
                                             obj->sgt->orig_nents, GFP_KERNEL);
                if (err < 0)
                        goto free;
        } else {
                /*
                 * If the buffer object had no pages allocated and if it was
                 * not imported, it had to be allocated with the DMA API, so
                 * the DMA API helper can be used.
                 */
                err = dma_get_sgtable(dev, sgt, obj->vaddr, obj->iova,
                                      obj->gem.size);
                if (err < 0)
                        goto free;
        }

        return sgt;

free:
        kfree(sgt);
        return ERR_PTR(err);
}

static void tegra_bo_unpin(struct device *dev, struct sg_table *sgt)
{
        if (sgt) {
                sg_free_table(sgt);
                kfree(sgt);
        }
}

static void *tegra_bo_mmap(struct host1x_bo *bo)
{
        struct tegra_bo *obj = host1x_to_tegra_bo(bo);
        struct dma_buf_map map;
        int ret;

        if (obj->vaddr) {
                return obj->vaddr;
        } else if (obj->gem.import_attach) {
                ret = dma_buf_vmap(obj->gem.import_attach->dmabuf, &map);
                return ret ? NULL : map.vaddr;
        } else {
                return vmap(obj->pages, obj->num_pages, VM_MAP,
                            pgprot_writecombine(PAGE_KERNEL));
        }
}

static void tegra_bo_munmap(struct host1x_bo *bo, void *addr)
{
        struct tegra_bo *obj = host1x_to_tegra_bo(bo);
        struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(addr);

        if (obj->vaddr)
                return;
        else if (obj->gem.import_attach)
                dma_buf_vunmap(obj->gem.import_attach->dmabuf, &map);
        else
                vunmap(addr);
}

static struct host1x_bo *tegra_bo_get(struct host1x_bo *bo)
{
        struct tegra_bo *obj = host1x_to_tegra_bo(bo);

        drm_gem_object_get(&obj->gem);

        return bo;
}

static const struct host1x_bo_ops tegra_bo_ops = {
        .get = tegra_bo_get,
        .put = tegra_bo_put,
        .pin = tegra_bo_pin,
        .unpin = tegra_bo_unpin,
        .mmap = tegra_bo_mmap,
        .munmap = tegra_bo_munmap,
};

static int tegra_bo_iommu_map(struct tegra_drm *tegra, struct tegra_bo *bo)
{
        int prot = IOMMU_READ | IOMMU_WRITE;
        int err;

        if (bo->mm)
                return -EBUSY;

        bo->mm = kzalloc(sizeof(*bo->mm), GFP_KERNEL);
        if (!bo->mm)
                return -ENOMEM;

        mutex_lock(&tegra->mm_lock);

        err = drm_mm_insert_node_generic(&tegra->mm,
                                         bo->mm, bo->gem.size, PAGE_SIZE, 0, 0);
        if (err < 0) {
                dev_err(tegra->drm->dev, "out of I/O virtual memory: %d\n",
                        err);
                goto unlock;
        }

        bo->iova = bo->mm->start;

        bo->size = iommu_map_sgtable(tegra->domain, bo->iova, bo->sgt, prot);
        if (!bo->size) {
                dev_err(tegra->drm->dev, "failed to map buffer\n");
                err = -ENOMEM;
                goto remove;
        }

        mutex_unlock(&tegra->mm_lock);

        return 0;

remove:
        drm_mm_remove_node(bo->mm);
unlock:
        mutex_unlock(&tegra->mm_lock);
        kfree(bo->mm);
        return err;
}

static int tegra_bo_iommu_unmap(struct tegra_drm *tegra, struct tegra_bo *bo)
{
        if (!bo->mm)
                return 0;

        mutex_lock(&tegra->mm_lock);
        iommu_unmap(tegra->domain, bo->iova, bo->size);
        drm_mm_remove_node(bo->mm);
        mutex_unlock(&tegra->mm_lock);

        kfree(bo->mm);

        return 0;
}

static const struct drm_gem_object_funcs tegra_gem_object_funcs = {
        .free = tegra_bo_free_object,
        .export = tegra_gem_prime_export,
        .vm_ops = &tegra_bo_vm_ops,
};

static struct tegra_bo *tegra_bo_alloc_object(struct drm_device *drm,
                                              size_t size)
{
        struct tegra_bo *bo;
        int err;

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

        bo->gem.funcs = &tegra_gem_object_funcs;

        host1x_bo_init(&bo->base, &tegra_bo_ops);
        size = round_up(size, PAGE_SIZE);

        err = drm_gem_object_init(drm, &bo->gem, size);
        if (err < 0)
                goto free;

        err = drm_gem_create_mmap_offset(&bo->gem);
        if (err < 0)
                goto release;

        return bo;

release:
        drm_gem_object_release(&bo->gem);
free:
        kfree(bo);
        return ERR_PTR(err);
}

static void tegra_bo_free(struct drm_device *drm, struct tegra_bo *bo)
{
        if (bo->pages) {
                dma_unmap_sgtable(drm->dev, bo->sgt, DMA_FROM_DEVICE, 0);
                drm_gem_put_pages(&bo->gem, bo->pages, true, true);
                sg_free_table(bo->sgt);
                kfree(bo->sgt);
        } else if (bo->vaddr) {
                dma_free_wc(drm->dev, bo->gem.size, bo->vaddr, bo->iova);
        }
}

static int tegra_bo_get_pages(struct drm_device *drm, struct tegra_bo *bo)
{
        int err;

        bo->pages = drm_gem_get_pages(&bo->gem);
        if (IS_ERR(bo->pages))
                return PTR_ERR(bo->pages);

        bo->num_pages = bo->gem.size >> PAGE_SHIFT;

        bo->sgt = drm_prime_pages_to_sg(bo->gem.dev, bo->pages, bo->num_pages);
        if (IS_ERR(bo->sgt)) {
                err = PTR_ERR(bo->sgt);
                goto put_pages;
        }

        err = dma_map_sgtable(drm->dev, bo->sgt, DMA_FROM_DEVICE, 0);
        if (err)
                goto free_sgt;

        return 0;

free_sgt:
        sg_free_table(bo->sgt);
        kfree(bo->sgt);
put_pages:
        drm_gem_put_pages(&bo->gem, bo->pages, false, false);
        return err;
}

static int tegra_bo_alloc(struct drm_device *drm, struct tegra_bo *bo)
{
        struct tegra_drm *tegra = drm->dev_private;
        int err;

        if (tegra->domain) {
                err = tegra_bo_get_pages(drm, bo);
                if (err < 0)
                        return err;

                err = tegra_bo_iommu_map(tegra, bo);
                if (err < 0) {
                        tegra_bo_free(drm, bo);
                        return err;
                }
        } else {
                size_t size = bo->gem.size;

                bo->vaddr = dma_alloc_wc(drm->dev, size, &bo->iova,
                                         GFP_KERNEL | __GFP_NOWARN);
                if (!bo->vaddr) {
                        dev_err(drm->dev,
                                "failed to allocate buffer of size %zu\n",
                                size);
                        return -ENOMEM;
                }
        }

        return 0;
}

struct tegra_bo *tegra_bo_create(struct drm_device *drm, size_t size,
                                 unsigned long flags)
{
        struct tegra_bo *bo;
        int err;

        bo = tegra_bo_alloc_object(drm, size);
        if (IS_ERR(bo))
                return bo;

        err = tegra_bo_alloc(drm, bo);
        if (err < 0)
                goto release;

        if (flags & DRM_TEGRA_GEM_CREATE_TILED)
                bo->tiling.mode = TEGRA_BO_TILING_MODE_TILED;

        if (flags & DRM_TEGRA_GEM_CREATE_BOTTOM_UP)
                bo->flags |= TEGRA_BO_BOTTOM_UP;

        return bo;

release:
        drm_gem_object_release(&bo->gem);
        kfree(bo);
        return ERR_PTR(err);
}

struct tegra_bo *tegra_bo_create_with_handle(struct drm_file *file,
                                             struct drm_device *drm,
                                             size_t size,
                                             unsigned long flags,
                                             u32 *handle)
{
        struct tegra_bo *bo;
        int err;

        bo = tegra_bo_create(drm, size, flags);
        if (IS_ERR(bo))
                return bo;

        err = drm_gem_handle_create(file, &bo->gem, handle);
        if (err) {
                tegra_bo_free_object(&bo->gem);
                return ERR_PTR(err);
        }

        drm_gem_object_put(&bo->gem);

        return bo;
}

static struct tegra_bo *tegra_bo_import(struct drm_device *drm,
                                        struct dma_buf *buf)
{
        struct tegra_drm *tegra = drm->dev_private;
        struct dma_buf_attachment *attach;
        struct tegra_bo *bo;
        int err;

        bo = tegra_bo_alloc_object(drm, buf->size);
        if (IS_ERR(bo))
                return bo;

        attach = dma_buf_attach(buf, drm->dev);
        if (IS_ERR(attach)) {
                err = PTR_ERR(attach);
                goto free;
        }

        get_dma_buf(buf);

        bo->sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
        if (IS_ERR(bo->sgt)) {
                err = PTR_ERR(bo->sgt);
                goto detach;
        }

        if (tegra->domain) {
                err = tegra_bo_iommu_map(tegra, bo);
                if (err < 0)
                        goto detach;
        }

        bo->gem.import_attach = attach;

        return bo;

detach:
        if (!IS_ERR_OR_NULL(bo->sgt))
                dma_buf_unmap_attachment(attach, bo->sgt, DMA_TO_DEVICE);

        dma_buf_detach(buf, attach);
        dma_buf_put(buf);
free:
        drm_gem_object_release(&bo->gem);
        kfree(bo);
        return ERR_PTR(err);
}

void tegra_bo_free_object(struct drm_gem_object *gem)
{
        struct tegra_drm *tegra = gem->dev->dev_private;
        struct tegra_bo *bo = to_tegra_bo(gem);

        if (tegra->domain)
                tegra_bo_iommu_unmap(tegra, bo);

        if (gem->import_attach) {
                dma_buf_unmap_attachment(gem->import_attach, bo->sgt,
                                         DMA_TO_DEVICE);
                drm_prime_gem_destroy(gem, NULL);
        } else {
                tegra_bo_free(gem->dev, bo);
        }

        drm_gem_object_release(gem);
        kfree(bo);
}

int tegra_bo_dumb_create(struct drm_file *file, struct drm_device *drm,
                         struct drm_mode_create_dumb *args)
{
        unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
        struct tegra_drm *tegra = drm->dev_private;
        struct tegra_bo *bo;

        args->pitch = round_up(min_pitch, tegra->pitch_align);
        args->size = args->pitch * args->height;

        bo = tegra_bo_create_with_handle(file, drm, args->size, 0,
                                         &args->handle);
        if (IS_ERR(bo))
                return PTR_ERR(bo);

        return 0;
}

static vm_fault_t tegra_bo_fault(struct vm_fault *vmf)
{
        struct vm_area_struct *vma = vmf->vma;
        struct drm_gem_object *gem = vma->vm_private_data;
        struct tegra_bo *bo = to_tegra_bo(gem);
        struct page *page;
        pgoff_t offset;

        if (!bo->pages)
                return VM_FAULT_SIGBUS;

        offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
        page = bo->pages[offset];

        return vmf_insert_page(vma, vmf->address, page);
}

const struct vm_operations_struct tegra_bo_vm_ops = {
        .fault = tegra_bo_fault,
        .open = drm_gem_vm_open,
        .close = drm_gem_vm_close,
};

int __tegra_gem_mmap(struct drm_gem_object *gem, struct vm_area_struct *vma)
{
        struct tegra_bo *bo = to_tegra_bo(gem);

        if (!bo->pages) {
                unsigned long vm_pgoff = vma->vm_pgoff;
                int err;

                /*
                 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(),
                 * and set the vm_pgoff (used as a fake buffer offset by DRM)
                 * to 0 as we want to map the whole buffer.
                 */
                vma->vm_flags &= ~VM_PFNMAP;
                vma->vm_pgoff = 0;

                err = dma_mmap_wc(gem->dev->dev, vma, bo->vaddr, bo->iova,
                                  gem->size);
                if (err < 0) {
                        drm_gem_vm_close(vma);
                        return err;
                }

                vma->vm_pgoff = vm_pgoff;
        } else {
                pgprot_t prot = vm_get_page_prot(vma->vm_flags);

                vma->vm_flags |= VM_MIXEDMAP;
                vma->vm_flags &= ~VM_PFNMAP;

                vma->vm_page_prot = pgprot_writecombine(prot);
        }

        return 0;
}

int tegra_drm_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct drm_gem_object *gem;
        int err;

        err = drm_gem_mmap(file, vma);
        if (err < 0)
                return err;

        gem = vma->vm_private_data;

        return __tegra_gem_mmap(gem, vma);
}

static struct sg_table *
tegra_gem_prime_map_dma_buf(struct dma_buf_attachment *attach,
                            enum dma_data_direction dir)
{
        struct drm_gem_object *gem = attach->dmabuf->priv;
        struct tegra_bo *bo = to_tegra_bo(gem);
        struct sg_table *sgt;

        sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
        if (!sgt)
                return NULL;

        if (bo->pages) {
                if (sg_alloc_table_from_pages(sgt, bo->pages, bo->num_pages,
                                              0, gem->size, GFP_KERNEL) < 0)
                        goto free;
        } else {
                if (dma_get_sgtable(attach->dev, sgt, bo->vaddr, bo->iova,
                                    gem->size) < 0)
                        goto free;
        }

        if (dma_map_sgtable(attach->dev, sgt, dir, 0))
                goto free;

        return sgt;

free:
        sg_free_table(sgt);
        kfree(sgt);
        return NULL;
}

static void tegra_gem_prime_unmap_dma_buf(struct dma_buf_attachment *attach,
                                          struct sg_table *sgt,
                                          enum dma_data_direction dir)
{
        struct drm_gem_object *gem = attach->dmabuf->priv;
        struct tegra_bo *bo = to_tegra_bo(gem);

        if (bo->pages)
                dma_unmap_sgtable(attach->dev, sgt, dir, 0);

        sg_free_table(sgt);
        kfree(sgt);
}

static void tegra_gem_prime_release(struct dma_buf *buf)
{
        drm_gem_dmabuf_release(buf);
}

static int tegra_gem_prime_begin_cpu_access(struct dma_buf *buf,
                                            enum dma_data_direction direction)
{
        struct drm_gem_object *gem = buf->priv;
        struct tegra_bo *bo = to_tegra_bo(gem);
        struct drm_device *drm = gem->dev;

        if (bo->pages)
                dma_sync_sgtable_for_cpu(drm->dev, bo->sgt, DMA_FROM_DEVICE);

        return 0;
}

static int tegra_gem_prime_end_cpu_access(struct dma_buf *buf,
                                          enum dma_data_direction direction)
{
        struct drm_gem_object *gem = buf->priv;
        struct tegra_bo *bo = to_tegra_bo(gem);
        struct drm_device *drm = gem->dev;

        if (bo->pages)
                dma_sync_sgtable_for_device(drm->dev, bo->sgt, DMA_TO_DEVICE);

        return 0;
}

static int tegra_gem_prime_mmap(struct dma_buf *buf, struct vm_area_struct *vma)
{
        struct drm_gem_object *gem = buf->priv;
        int err;

        err = drm_gem_mmap_obj(gem, gem->size, vma);
        if (err < 0)
                return err;

        return __tegra_gem_mmap(gem, vma);
}

static int tegra_gem_prime_vmap(struct dma_buf *buf, struct dma_buf_map *map)
{
        struct drm_gem_object *gem = buf->priv;
        struct tegra_bo *bo = to_tegra_bo(gem);

        dma_buf_map_set_vaddr(map, bo->vaddr);

        return 0;
}

static void tegra_gem_prime_vunmap(struct dma_buf *buf, struct dma_buf_map *map)
{
}

static const struct dma_buf_ops tegra_gem_prime_dmabuf_ops = {
        .map_dma_buf = tegra_gem_prime_map_dma_buf,
        .unmap_dma_buf = tegra_gem_prime_unmap_dma_buf,
        .release = tegra_gem_prime_release,
        .begin_cpu_access = tegra_gem_prime_begin_cpu_access,
        .end_cpu_access = tegra_gem_prime_end_cpu_access,
        .mmap = tegra_gem_prime_mmap,
        .vmap = tegra_gem_prime_vmap,
        .vunmap = tegra_gem_prime_vunmap,
};

struct dma_buf *tegra_gem_prime_export(struct drm_gem_object *gem,
                                       int flags)
{
        DEFINE_DMA_BUF_EXPORT_INFO(exp_info);

        exp_info.exp_name = KBUILD_MODNAME;
        exp_info.owner = gem->dev->driver->fops->owner;
        exp_info.ops = &tegra_gem_prime_dmabuf_ops;
        exp_info.size = gem->size;
        exp_info.flags = flags;
        exp_info.priv = gem;

        return drm_gem_dmabuf_export(gem->dev, &exp_info);
}

struct drm_gem_object *tegra_gem_prime_import(struct drm_device *drm,
                                              struct dma_buf *buf)
{
        struct tegra_bo *bo;

        if (buf->ops == &tegra_gem_prime_dmabuf_ops) {
                struct drm_gem_object *gem = buf->priv;

                if (gem->dev == drm) {
                        drm_gem_object_get(gem);
                        return gem;
                }
        }

        bo = tegra_bo_import(drm, buf);
        if (IS_ERR(bo))
                return ERR_CAST(bo);

        return &bo->gem;
}

struct host1x_bo *tegra_gem_lookup(struct drm_file *file, u32 handle)
{
        struct drm_gem_object *gem;
        struct tegra_bo *bo;

        gem = drm_gem_object_lookup(file, handle);
        if (!gem)
                return NULL;

        bo = to_tegra_bo(gem);
        return &bo->base;
}