/*
 * Copyright (C) 2015 Etnaviv Project
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "common.xml.h"
#include "etnaviv_cmdbuf.h"
#include "etnaviv_drv.h"
#include "etnaviv_gem.h"
#include "etnaviv_gpu.h"
#include "etnaviv_iommu.h"
#include "etnaviv_mmu.h"

static void etnaviv_domain_unmap(struct etnaviv_iommu_domain *domain,
                                 unsigned long iova, size_t size)
{
        size_t unmapped_page, unmapped = 0;
        size_t pgsize = SZ_4K;

        if (!IS_ALIGNED(iova | size, pgsize)) {
                pr_err("unaligned: iova 0x%lx size 0x%zx min_pagesz 0x%x\n",
                       iova, size, pgsize);
                return;
        }

        while (unmapped < size) {
                unmapped_page = domain->ops->unmap(domain, iova, pgsize);
                if (!unmapped_page)
                        break;

                iova += unmapped_page;
                unmapped += unmapped_page;
        }
}

static int etnaviv_domain_map(struct etnaviv_iommu_domain *domain,
                              unsigned long iova, phys_addr_t paddr,
                              size_t size, int prot)
{
        unsigned long orig_iova = iova;
        size_t pgsize = SZ_4K;
        size_t orig_size = size;
        int ret = 0;

        if (!IS_ALIGNED(iova | paddr | size, pgsize)) {
                pr_err("unaligned: iova 0x%lx pa %pa size 0x%zx min_pagesz 0x%x\n",
                       iova, &paddr, size, pgsize);
                return -EINVAL;
        }

        while (size) {
                ret = domain->ops->map(domain, iova, paddr, pgsize, prot);
                if (ret)
                        break;

                iova += pgsize;
                paddr += pgsize;
                size -= pgsize;
        }

        /* unroll mapping in case something went wrong */
        if (ret)
                etnaviv_domain_unmap(domain, orig_iova, orig_size - size);

        return ret;
}

static int etnaviv_iommu_map(struct etnaviv_iommu *iommu, u32 iova,
                             struct sg_table *sgt, unsigned len, int prot)
{
        struct etnaviv_iommu_domain *domain = iommu->domain;
        struct scatterlist *sg;
        unsigned int da = iova;
        unsigned int i, j;
        int ret;

        if (!domain || !sgt)
                return -EINVAL;

        for_each_sg(sgt->sgl, sg, sgt->nents, i) {
                u32 pa = sg_dma_address(sg) - sg->offset;
                size_t bytes = sg_dma_len(sg) + sg->offset;

                VERB("map[%d]: %08x %08x(%zx)", i, iova, pa, bytes);

                ret = etnaviv_domain_map(domain, da, pa, bytes, prot);
                if (ret)
                        goto fail;

                da += bytes;
        }

        return 0;

fail:
        da = iova;

        for_each_sg(sgt->sgl, sg, i, j) {
                size_t bytes = sg_dma_len(sg) + sg->offset;

                etnaviv_domain_unmap(domain, da, bytes);
                da += bytes;
        }
        return ret;
}

static void etnaviv_iommu_unmap(struct etnaviv_iommu *iommu, u32 iova,
                                struct sg_table *sgt, unsigned len)
{
        struct etnaviv_iommu_domain *domain = iommu->domain;
        struct scatterlist *sg;
        unsigned int da = iova;
        int i;

        for_each_sg(sgt->sgl, sg, sgt->nents, i) {
                size_t bytes = sg_dma_len(sg) + sg->offset;

                etnaviv_domain_unmap(domain, da, bytes);

                VERB("unmap[%d]: %08x(%zx)", i, iova, bytes);

                BUG_ON(!PAGE_ALIGNED(bytes));

                da += bytes;
        }
}

static void etnaviv_iommu_remove_mapping(struct etnaviv_iommu *mmu,
        struct etnaviv_vram_mapping *mapping)
{
        struct etnaviv_gem_object *etnaviv_obj = mapping->object;

        etnaviv_iommu_unmap(mmu, mapping->vram_node.start,
                            etnaviv_obj->sgt, etnaviv_obj->base.size);
        drm_mm_remove_node(&mapping->vram_node);
}

static int etnaviv_iommu_find_iova(struct etnaviv_iommu *mmu,
                                   struct drm_mm_node *node, size_t size)
{
        struct etnaviv_vram_mapping *free = NULL;
        enum drm_mm_insert_mode mode = DRM_MM_INSERT_LOW;
        int ret;

        lockdep_assert_held(&mmu->lock);

        while (1) {
                struct etnaviv_vram_mapping *m, *n;
                struct drm_mm_scan scan;
                struct list_head list;
                bool found;

                ret = drm_mm_insert_node_in_range(&mmu->mm, node,
                                                  size, 0, 0,
                                                  mmu->last_iova, U64_MAX,
                                                  mode);
                if (ret != -ENOSPC)
                        break;

                /*
                 * If we did not search from the start of the MMU region,
                 * try again in case there are free slots.
                 */
                if (mmu->last_iova) {
                        mmu->last_iova = 0;
                        mmu->need_flush = true;
                        continue;
                }

                /* Try to retire some entries */
                drm_mm_scan_init(&scan, &mmu->mm, size, 0, 0, mode);

                found = 0;
                INIT_LIST_HEAD(&list);
                list_for_each_entry(free, &mmu->mappings, mmu_node) {
                        /* If this vram node has not been used, skip this. */
                        if (!free->vram_node.mm)
                                continue;

                        /*
                         * If the iova is pinned, then it's in-use,
                         * so we must keep its mapping.
                         */
                        if (free->use)
                                continue;

                        list_add(&free->scan_node, &list);
                        if (drm_mm_scan_add_block(&scan, &free->vram_node)) {
                                found = true;
                                break;
                        }
                }

                if (!found) {
                        /* Nothing found, clean up and fail */
                        list_for_each_entry_safe(m, n, &list, scan_node)
                                BUG_ON(drm_mm_scan_remove_block(&scan, &m->vram_node));
                        break;
                }

                /*
                 * drm_mm does not allow any other operations while
                 * scanning, so we have to remove all blocks first.
                 * If drm_mm_scan_remove_block() returns false, we
                 * can leave the block pinned.
                 */
                list_for_each_entry_safe(m, n, &list, scan_node)
                        if (!drm_mm_scan_remove_block(&scan, &m->vram_node))
                                list_del_init(&m->scan_node);

                /*
                 * Unmap the blocks which need to be reaped from the MMU.
                 * Clear the mmu pointer to prevent the mapping_get finding
                 * this mapping.
                 */
                list_for_each_entry_safe(m, n, &list, scan_node) {
                        etnaviv_iommu_remove_mapping(mmu, m);
                        m->mmu = NULL;
                        list_del_init(&m->mmu_node);
                        list_del_init(&m->scan_node);
                }

                mode = DRM_MM_INSERT_EVICT;

                /*
                 * We removed enough mappings so that the new allocation will
                 * succeed, retry the allocation one more time.
                 */
        }

        return ret;
}

int etnaviv_iommu_map_gem(struct etnaviv_iommu *mmu,
        struct etnaviv_gem_object *etnaviv_obj, u32 memory_base,
        struct etnaviv_vram_mapping *mapping)
{
        struct sg_table *sgt = etnaviv_obj->sgt;
        struct drm_mm_node *node;
        int ret;

        lockdep_assert_held(&etnaviv_obj->lock);

        mutex_lock(&mmu->lock);

        /* v1 MMU can optimize single entry (contiguous) scatterlists */
        if (mmu->version == ETNAVIV_IOMMU_V1 &&
            sgt->nents == 1 && !(etnaviv_obj->flags & ETNA_BO_FORCE_MMU)) {
                u32 iova;

                iova = sg_dma_address(sgt->sgl) - memory_base;
                if (iova < 0x80000000 - sg_dma_len(sgt->sgl)) {
                        mapping->iova = iova;
                        list_add_tail(&mapping->mmu_node, &mmu->mappings);
                        ret = 0;
                        goto unlock;
                }
        }

        node = &mapping->vram_node;

        ret = etnaviv_iommu_find_iova(mmu, node, etnaviv_obj->base.size);
        if (ret < 0)
                goto unlock;

        mmu->last_iova = node->start + etnaviv_obj->base.size;
        mapping->iova = node->start;
        ret = etnaviv_iommu_map(mmu, node->start, sgt, etnaviv_obj->base.size,
                                ETNAVIV_PROT_READ | ETNAVIV_PROT_WRITE);

        if (ret < 0) {
                drm_mm_remove_node(node);
                goto unlock;
        }

        list_add_tail(&mapping->mmu_node, &mmu->mappings);
        mmu->need_flush = true;
unlock:
        mutex_unlock(&mmu->lock);

        return ret;
}

void etnaviv_iommu_unmap_gem(struct etnaviv_iommu *mmu,
        struct etnaviv_vram_mapping *mapping)
{
        WARN_ON(mapping->use);

        mutex_lock(&mmu->lock);

        /* If the vram node is on the mm, unmap and remove the node */
        if (mapping->vram_node.mm == &mmu->mm)
                etnaviv_iommu_remove_mapping(mmu, mapping);

        list_del(&mapping->mmu_node);
        mmu->need_flush = true;
        mutex_unlock(&mmu->lock);
}

void etnaviv_iommu_destroy(struct etnaviv_iommu *mmu)
{
        drm_mm_takedown(&mmu->mm);
        mmu->domain->ops->free(mmu->domain);
        kfree(mmu);
}

struct etnaviv_iommu *etnaviv_iommu_new(struct etnaviv_gpu *gpu)
{
        enum etnaviv_iommu_version version;
        struct etnaviv_iommu *mmu;

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

        if (!(gpu->identity.minor_features1 & chipMinorFeatures1_MMU_VERSION)) {
                mmu->domain = etnaviv_iommuv1_domain_alloc(gpu);
                version = ETNAVIV_IOMMU_V1;
        } else {
                mmu->domain = etnaviv_iommuv2_domain_alloc(gpu);
                version = ETNAVIV_IOMMU_V2;
        }

        if (!mmu->domain) {
                dev_err(gpu->dev, "Failed to allocate GPU IOMMU domain\n");
                kfree(mmu);
                return ERR_PTR(-ENOMEM);
        }

        mmu->gpu = gpu;
        mmu->version = version;
        mutex_init(&mmu->lock);
        INIT_LIST_HEAD(&mmu->mappings);

        drm_mm_init(&mmu->mm, mmu->domain->base, mmu->domain->size);

        return mmu;
}

void etnaviv_iommu_restore(struct etnaviv_gpu *gpu)
{
        if (gpu->mmu->version == ETNAVIV_IOMMU_V1)
                etnaviv_iommuv1_restore(gpu);
        else
                etnaviv_iommuv2_restore(gpu);
}

int etnaviv_iommu_get_suballoc_va(struct etnaviv_gpu *gpu, dma_addr_t paddr,
                                  struct drm_mm_node *vram_node, size_t size,
                                  u32 *iova)
{
        struct etnaviv_iommu *mmu = gpu->mmu;

        if (mmu->version == ETNAVIV_IOMMU_V1) {
                *iova = paddr - gpu->memory_base;
                return 0;
        } else {
                int ret;

                mutex_lock(&mmu->lock);
                ret = etnaviv_iommu_find_iova(mmu, vram_node, size);
                if (ret < 0) {
                        mutex_unlock(&mmu->lock);
                        return ret;
                }
                ret = etnaviv_domain_map(mmu->domain, vram_node->start, paddr,
                                         size, ETNAVIV_PROT_READ);
                if (ret < 0) {
                        drm_mm_remove_node(vram_node);
                        mutex_unlock(&mmu->lock);
                        return ret;
                }
                mmu->last_iova = vram_node->start + size;
                gpu->mmu->need_flush = true;
                mutex_unlock(&mmu->lock);

                *iova = (u32)vram_node->start;
                return 0;
        }
}

void etnaviv_iommu_put_suballoc_va(struct etnaviv_gpu *gpu,
                                   struct drm_mm_node *vram_node, size_t size,
                                   u32 iova)
{
        struct etnaviv_iommu *mmu = gpu->mmu;

        if (mmu->version == ETNAVIV_IOMMU_V2) {
                mutex_lock(&mmu->lock);
                etnaviv_domain_unmap(mmu->domain, iova, size);
                drm_mm_remove_node(vram_node);
                mutex_unlock(&mmu->lock);
        }
}
size_t etnaviv_iommu_dump_size(struct etnaviv_iommu *iommu)
{
        return iommu->domain->ops->dump_size(iommu->domain);
}

void etnaviv_iommu_dump(struct etnaviv_iommu *iommu, void *buf)
{
        iommu->domain->ops->dump(iommu->domain, buf);
}