// SPDX-License-Identifier: MIT
/*
 * Copyright © 2014-2016 Intel Corporation
 */

#include <linux/highmem.h>
#include <linux/shmem_fs.h>
#include <linux/swap.h>

#include <drm/drm_cache.h>
#include <drm/drm_print.h>

#include "gt/intel_gt.h"
#include "i915_drv.h"
#include "i915_gem_object.h"
#include "i915_gem_object_frontbuffer.h"
#include "i915_gem_region.h"
#include "i915_gem_tiling.h"
#include "i915_scatterlist.h"

static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
{
        struct address_space *mapping = obj->base.filp->f_mapping;
        struct drm_i915_private *i915 = to_i915(obj->base.dev);
        struct scatterlist *sg;
        struct sg_table *st;
        dma_addr_t dma;
        void *vaddr;
        void *dst;
        int i;

        /* Contiguous chunk, with a single scatterlist element */
        if (overflows_type(obj->base.size, sg->length))
                return -E2BIG;

        if (GEM_WARN_ON(i915_gem_object_needs_bit17_swizzle(obj)))
                return -EINVAL;

        /*
         * Always aligning to the object size, allows a single allocation
         * to handle all possible callers, and given typical object sizes,
         * the alignment of the buddy allocation will naturally match.
         */
        vaddr = dma_alloc_coherent(obj->base.dev->dev,
                                   roundup_pow_of_two(obj->base.size),
                                   &dma, GFP_KERNEL);
        if (!vaddr)
                return -ENOMEM;

        st = kmalloc_obj(*st);
        if (!st)
                goto err_pci;

        if (sg_alloc_table(st, 1, GFP_KERNEL))
                goto err_st;

        sg = st->sgl;
        sg->offset = 0;
        sg->length = obj->base.size;

        sg_assign_page(sg, (struct page *)vaddr);
        sg_dma_address(sg) = dma;
        sg_dma_len(sg) = obj->base.size;

        dst = vaddr;
        for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
                struct page *page;

                page = shmem_read_mapping_page(mapping, i);
                if (IS_ERR(page))
                        goto err_st;

                memcpy_from_page(dst, page, 0, PAGE_SIZE);
                drm_clflush_virt_range(dst, PAGE_SIZE);

                put_page(page);
                dst += PAGE_SIZE;
        }

        intel_gt_chipset_flush(to_gt(i915));

        /* We're no longer struct page backed */
        obj->mem_flags &= ~I915_BO_FLAG_STRUCT_PAGE;
        __i915_gem_object_set_pages(obj, st);

        return 0;

err_st:
        kfree(st);
err_pci:
        dma_free_coherent(obj->base.dev->dev,
                          roundup_pow_of_two(obj->base.size),
                          vaddr, dma);
        return -ENOMEM;
}

void
i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj,
                               struct sg_table *pages)
{
        dma_addr_t dma = sg_dma_address(pages->sgl);
        void *vaddr = sg_page(pages->sgl);

        __i915_gem_object_release_shmem(obj, pages, false);

        if (obj->mm.dirty) {
                struct address_space *mapping = obj->base.filp->f_mapping;
                void *src = vaddr;
                int i;

                for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
                        struct page *page;

                        page = shmem_read_mapping_page(mapping, i);
                        if (IS_ERR(page))
                                continue;

                        drm_clflush_virt_range(src, PAGE_SIZE);
                        memcpy_to_page(page, 0, src, PAGE_SIZE);

                        set_page_dirty(page);
                        if (obj->mm.madv == I915_MADV_WILLNEED)
                                mark_page_accessed(page);
                        put_page(page);

                        src += PAGE_SIZE;
                }
                obj->mm.dirty = false;
        }

        sg_free_table(pages);
        kfree(pages);

        dma_free_coherent(obj->base.dev->dev,
                          roundup_pow_of_two(obj->base.size),
                          vaddr, dma);
}

int i915_gem_object_pwrite_phys(struct drm_i915_gem_object *obj,
                                const struct drm_i915_gem_pwrite *args)
{
        void *vaddr = sg_page(obj->mm.pages->sgl) + args->offset;
        char __user *user_data = u64_to_user_ptr(args->data_ptr);
        struct drm_i915_private *i915 = to_i915(obj->base.dev);
        int err;

        err = i915_gem_object_wait(obj,
                                   I915_WAIT_INTERRUPTIBLE |
                                   I915_WAIT_ALL,
                                   MAX_SCHEDULE_TIMEOUT);
        if (err)
                return err;

        /*
         * We manually control the domain here and pretend that it
         * remains coherent i.e. in the GTT domain, like shmem_pwrite.
         */
        i915_gem_object_invalidate_frontbuffer(obj, ORIGIN_CPU);

        if (copy_from_user(vaddr, user_data, args->size))
                return -EFAULT;

        drm_clflush_virt_range(vaddr, args->size);
        intel_gt_chipset_flush(to_gt(i915));

        i915_gem_object_flush_frontbuffer(obj, ORIGIN_CPU);
        return 0;
}

int i915_gem_object_pread_phys(struct drm_i915_gem_object *obj,
                               const struct drm_i915_gem_pread *args)
{
        void *vaddr = sg_page(obj->mm.pages->sgl) + args->offset;
        char __user *user_data = u64_to_user_ptr(args->data_ptr);
        int err;

        err = i915_gem_object_wait(obj,
                                   I915_WAIT_INTERRUPTIBLE,
                                   MAX_SCHEDULE_TIMEOUT);
        if (err)
                return err;

        drm_clflush_virt_range(vaddr, args->size);
        if (copy_to_user(user_data, vaddr, args->size))
                return -EFAULT;

        return 0;
}

static int i915_gem_object_shmem_to_phys(struct drm_i915_gem_object *obj)
{
        struct sg_table *pages;
        int err;

        pages = __i915_gem_object_unset_pages(obj);

        err = i915_gem_object_get_pages_phys(obj);
        if (err)
                goto err_xfer;

        /* Perma-pin (until release) the physical set of pages */
        __i915_gem_object_pin_pages(obj);

        if (!IS_ERR_OR_NULL(pages))
                i915_gem_object_put_pages_shmem(obj, pages);

        i915_gem_object_release_memory_region(obj);
        return 0;

err_xfer:
        if (!IS_ERR_OR_NULL(pages))
                __i915_gem_object_set_pages(obj, pages);
        return err;
}

int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align)
{
        int err;

        assert_object_held(obj);

        if (align > obj->base.size)
                return -EINVAL;

        if (!i915_gem_object_is_shmem(obj))
                return -EINVAL;

        if (!i915_gem_object_has_struct_page(obj))
                return 0;

        err = i915_gem_object_unbind(obj, I915_GEM_OBJECT_UNBIND_ACTIVE);
        if (err)
                return err;

        if (obj->mm.madv != I915_MADV_WILLNEED)
                return -EFAULT;

        if (i915_gem_object_has_tiling_quirk(obj))
                return -EFAULT;

        if (obj->mm.mapping || i915_gem_object_has_pinned_pages(obj))
                return -EBUSY;

        if (unlikely(obj->mm.madv != I915_MADV_WILLNEED)) {
                drm_dbg(obj->base.dev,
                        "Attempting to obtain a purgeable object\n");
                return -EFAULT;
        }

        return i915_gem_object_shmem_to_phys(obj);
}

#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/i915_gem_phys.c"
#endif