// SPDX-License-Identifier: GPL-2.0+
/*
 * NVIDIA Tegra Video decoder driver
 *
 * Copyright (C) 2016-2019 GRATE-DRIVER project
 */

#include <linux/iommu.h>
#include <linux/iova.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>

#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)
#include <asm/dma-iommu.h>
#endif

#include "vde.h"

int tegra_vde_iommu_map(struct tegra_vde *vde,
                        struct sg_table *sgt,
                        struct iova **iovap,
                        size_t size)
{
        struct iova *iova;
        unsigned long shift;
        unsigned long end;
        dma_addr_t addr;

        end = vde->domain->geometry.aperture_end;
        size = iova_align(&vde->iova, size);
        shift = iova_shift(&vde->iova);

        iova = alloc_iova(&vde->iova, size >> shift, end >> shift, true);
        if (!iova)
                return -ENOMEM;

        addr = iova_dma_addr(&vde->iova, iova);

        size = iommu_map_sgtable(vde->domain, addr, sgt,
                                 IOMMU_READ | IOMMU_WRITE);
        if (!size) {
                __free_iova(&vde->iova, iova);
                return -ENXIO;
        }

        *iovap = iova;

        return 0;
}

void tegra_vde_iommu_unmap(struct tegra_vde *vde, struct iova *iova)
{
        unsigned long shift = iova_shift(&vde->iova);
        unsigned long size = iova_size(iova) << shift;
        dma_addr_t addr = iova_dma_addr(&vde->iova, iova);

        iommu_unmap(vde->domain, addr, size);
        __free_iova(&vde->iova, iova);
}

int tegra_vde_iommu_init(struct tegra_vde *vde)
{
        struct device *dev = vde->dev;
        struct iova *iova;
        unsigned long order;
        unsigned long shift;
        int err;

        vde->group = iommu_group_get(dev);
        if (!vde->group)
                return 0;

#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)
        if (dev->archdata.mapping) {
                struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);

                arm_iommu_detach_device(dev);
                arm_iommu_release_mapping(mapping);
        }
#endif
        vde->domain = iommu_paging_domain_alloc(dev);
        if (IS_ERR(vde->domain)) {
                err = PTR_ERR(vde->domain);
                vde->domain = NULL;
                goto put_group;
        }

        err = iova_cache_get();
        if (err)
                goto free_domain;

        order = __ffs(vde->domain->pgsize_bitmap);
        init_iova_domain(&vde->iova, 1UL << order, 0);

        err = iommu_attach_group(vde->domain, vde->group);
        if (err)
                goto put_iova;

        /*
         * We're using some static addresses that are not accessible by VDE
         * to trap invalid memory accesses.
         */
        shift = iova_shift(&vde->iova);
        iova = reserve_iova(&vde->iova, 0x60000000 >> shift,
                            0x70000000 >> shift);
        if (!iova) {
                err = -ENOMEM;
                goto detach_group;
        }

        vde->iova_resv_static_addresses = iova;

        /*
         * BSEV's end-address wraps around due to integer overflow during
         * of hardware context preparation if IOVA is allocated at the end
         * of address space and VDE can't handle that. Hence simply reserve
         * the last page to avoid the problem.
         */
        iova = reserve_iova(&vde->iova, 0xffffffff >> shift,
                            (0xffffffff >> shift) + 1);
        if (!iova) {
                err = -ENOMEM;
                goto unreserve_iova;
        }

        vde->iova_resv_last_page = iova;

        return 0;

unreserve_iova:
        __free_iova(&vde->iova, vde->iova_resv_static_addresses);
detach_group:
        iommu_detach_group(vde->domain, vde->group);
put_iova:
        put_iova_domain(&vde->iova);
        iova_cache_put();
free_domain:
        iommu_domain_free(vde->domain);
put_group:
        iommu_group_put(vde->group);

        return err;
}

void tegra_vde_iommu_deinit(struct tegra_vde *vde)
{
        if (vde->domain) {
                __free_iova(&vde->iova, vde->iova_resv_last_page);
                __free_iova(&vde->iova, vde->iova_resv_static_addresses);
                iommu_detach_group(vde->domain, vde->group);
                put_iova_domain(&vde->iova);
                iova_cache_put();
                iommu_domain_free(vde->domain);
                iommu_group_put(vde->group);

                vde->domain = NULL;
        }
}