// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2018 Intel Corporation
 * Copyright 2018 Google LLC.
 *
 * Author: Tomasz Figa <tfiga@chromium.org>
 * Author: Yong Zhi <yong.zhi@intel.com>
 */

#include <linux/vmalloc.h>

#include "ipu3.h"
#include "ipu3-css-pool.h"
#include "ipu3-mmu.h"
#include "ipu3-dmamap.h"

/*
 * Free a buffer allocated by imgu_dmamap_alloc_buffer()
 */
static void imgu_dmamap_free_buffer(struct page **pages,
                                    size_t size)
{
        int count = size >> PAGE_SHIFT;

        while (count--)
                __free_page(pages[count]);
        kvfree(pages);
}

/*
 * Based on the implementation of __iommu_dma_alloc_pages()
 * defined in drivers/iommu/dma-iommu.c
 */
static struct page **imgu_dmamap_alloc_buffer(size_t size,
                                              unsigned long order_mask,
                                              gfp_t gfp)
{
        struct page **pages;
        unsigned int i = 0, count = size >> PAGE_SHIFT;
        const gfp_t high_order_gfp = __GFP_NOWARN | __GFP_NORETRY;

        /* Allocate mem for array of page ptrs */
        pages = kvmalloc_array(count, sizeof(*pages), GFP_KERNEL);

        if (!pages)
                return NULL;

        order_mask &= (2U << MAX_ORDER) - 1;
        if (!order_mask)
                return NULL;

        gfp |= __GFP_HIGHMEM | __GFP_ZERO;

        while (count) {
                struct page *page = NULL;
                unsigned int order_size;

                for (order_mask &= (2U << __fls(count)) - 1;
                     order_mask; order_mask &= ~order_size) {
                        unsigned int order = __fls(order_mask);

                        order_size = 1U << order;
                        page = alloc_pages((order_mask - order_size) ?
                                           gfp | high_order_gfp : gfp, order);
                        if (!page)
                                continue;
                        if (!order)
                                break;
                        if (!PageCompound(page)) {
                                split_page(page, order);
                                break;
                        }

                        __free_pages(page, order);
                }
                if (!page) {
                        imgu_dmamap_free_buffer(pages, i << PAGE_SHIFT);
                        return NULL;
                }
                count -= order_size;
                while (order_size--)
                        pages[i++] = page++;
        }

        return pages;
}

/**
 * imgu_dmamap_alloc - allocate and map a buffer into KVA
 * @imgu: struct device pointer
 * @map: struct to store mapping variables
 * @len: size required
 *
 * Returns:
 *  KVA on success
 *  %NULL on failure
 */
void *imgu_dmamap_alloc(struct imgu_device *imgu, struct imgu_css_map *map,
                        size_t len)
{
        unsigned long shift = iova_shift(&imgu->iova_domain);
        unsigned int alloc_sizes = imgu->mmu->pgsize_bitmap;
        struct device *dev = &imgu->pci_dev->dev;
        size_t size = PAGE_ALIGN(len);
        struct page **pages;
        dma_addr_t iovaddr;
        struct iova *iova;
        int i, rval;

        dev_dbg(dev, "%s: allocating %zu\n", __func__, size);

        iova = alloc_iova(&imgu->iova_domain, size >> shift,
                          imgu->mmu->aperture_end >> shift, 0);
        if (!iova)
                return NULL;

        pages = imgu_dmamap_alloc_buffer(size, alloc_sizes >> PAGE_SHIFT,
                                         GFP_KERNEL);
        if (!pages)
                goto out_free_iova;

        /* Call IOMMU driver to setup pgt */
        iovaddr = iova_dma_addr(&imgu->iova_domain, iova);
        for (i = 0; i < size / PAGE_SIZE; ++i) {
                rval = imgu_mmu_map(imgu->mmu, iovaddr,
                                    page_to_phys(pages[i]), PAGE_SIZE);
                if (rval)
                        goto out_unmap;

                iovaddr += PAGE_SIZE;
        }

        /* Now grab a virtual region */
        map->vma = __get_vm_area(size, VM_USERMAP, VMALLOC_START, VMALLOC_END);
        if (!map->vma)
                goto out_unmap;

        map->vma->pages = pages;
        /* And map it in KVA */
        if (map_vm_area(map->vma, PAGE_KERNEL, pages))
                goto out_vunmap;

        map->size = size;
        map->daddr = iova_dma_addr(&imgu->iova_domain, iova);
        map->vaddr = map->vma->addr;

        dev_dbg(dev, "%s: allocated %zu @ IOVA %pad @ VA %p\n", __func__,
                size, &map->daddr, map->vma->addr);

        return map->vma->addr;

out_vunmap:
        vunmap(map->vma->addr);

out_unmap:
        imgu_dmamap_free_buffer(pages, size);
        imgu_mmu_unmap(imgu->mmu, iova_dma_addr(&imgu->iova_domain, iova),
                       i * PAGE_SIZE);
        map->vma = NULL;

out_free_iova:
        __free_iova(&imgu->iova_domain, iova);

        return NULL;
}

void imgu_dmamap_unmap(struct imgu_device *imgu, struct imgu_css_map *map)
{
        struct iova *iova;

        iova = find_iova(&imgu->iova_domain,
                         iova_pfn(&imgu->iova_domain, map->daddr));
        if (WARN_ON(!iova))
                return;

        imgu_mmu_unmap(imgu->mmu, iova_dma_addr(&imgu->iova_domain, iova),
                       iova_size(iova) << iova_shift(&imgu->iova_domain));

        __free_iova(&imgu->iova_domain, iova);
}

/*
 * Counterpart of imgu_dmamap_alloc
 */
void imgu_dmamap_free(struct imgu_device *imgu, struct imgu_css_map *map)
{
        struct vm_struct *area = map->vma;

        dev_dbg(&imgu->pci_dev->dev, "%s: freeing %zu @ IOVA %pad @ VA %p\n",
                __func__, map->size, &map->daddr, map->vaddr);

        if (!map->vaddr)
                return;

        imgu_dmamap_unmap(imgu, map);

        if (WARN_ON(!area) || WARN_ON(!area->pages))
                return;

        imgu_dmamap_free_buffer(area->pages, map->size);
        vunmap(map->vaddr);
        map->vaddr = NULL;
}

int imgu_dmamap_map_sg(struct imgu_device *imgu, struct scatterlist *sglist,
                       int nents, struct imgu_css_map *map)
{
        unsigned long shift = iova_shift(&imgu->iova_domain);
        struct scatterlist *sg;
        struct iova *iova;
        size_t size = 0;
        int i;

        for_each_sg(sglist, sg, nents, i) {
                if (sg->offset)
                        return -EINVAL;

                if (i != nents - 1 && !PAGE_ALIGNED(sg->length))
                        return -EINVAL;

                size += sg->length;
        }

        size = iova_align(&imgu->iova_domain, size);
        dev_dbg(&imgu->pci_dev->dev, "dmamap: mapping sg %d entries, %zu pages\n",
                nents, size >> shift);

        iova = alloc_iova(&imgu->iova_domain, size >> shift,
                          imgu->mmu->aperture_end >> shift, 0);
        if (!iova)
                return -ENOMEM;

        dev_dbg(&imgu->pci_dev->dev, "dmamap: iova low pfn %lu, high pfn %lu\n",
                iova->pfn_lo, iova->pfn_hi);

        if (imgu_mmu_map_sg(imgu->mmu, iova_dma_addr(&imgu->iova_domain, iova),
                            sglist, nents) < size)
                goto out_fail;

        memset(map, 0, sizeof(*map));
        map->daddr = iova_dma_addr(&imgu->iova_domain, iova);
        map->size = size;

        return 0;

out_fail:
        __free_iova(&imgu->iova_domain, iova);

        return -EFAULT;
}

int imgu_dmamap_init(struct imgu_device *imgu)
{
        unsigned long order, base_pfn;
        int ret = iova_cache_get();

        if (ret)
                return ret;

        order = __ffs(imgu->mmu->pgsize_bitmap);
        base_pfn = max_t(unsigned long, 1, imgu->mmu->aperture_start >> order);
        init_iova_domain(&imgu->iova_domain, 1UL << order, base_pfn);

        return 0;
}

void imgu_dmamap_exit(struct imgu_device *imgu)
{
        put_iova_domain(&imgu->iova_domain);
        iova_cache_put();
}