// SPDX-License-Identifier: GPL-2.0

/*
 * Copyright 2016-2019 HabanaLabs, Ltd.
 * All Rights Reserved.
 */

#include "habanalabs.h"
#include "../include/hw_ip/mmu/mmu_general.h"

#include <linux/genalloc.h>
#include <linux/slab.h>

static inline u64 get_phys_addr(struct hl_ctx *ctx, u64 shadow_addr);

static struct pgt_info *get_pgt_info(struct hl_ctx *ctx, u64 hop_addr)
{
        struct pgt_info *pgt_info = NULL;

        hash_for_each_possible(ctx->mmu_shadow_hash, pgt_info, node,
                                (unsigned long) hop_addr)
                if (hop_addr == pgt_info->shadow_addr)
                        break;

        return pgt_info;
}

static void _free_hop(struct hl_ctx *ctx, struct pgt_info *pgt_info)
{
        struct hl_device *hdev = ctx->hdev;

        gen_pool_free(hdev->mmu_pgt_pool, pgt_info->phys_addr,
                        hdev->asic_prop.mmu_hop_table_size);
        hash_del(&pgt_info->node);
        kfree((u64 *) (uintptr_t) pgt_info->shadow_addr);
        kfree(pgt_info);
}

static void free_hop(struct hl_ctx *ctx, u64 hop_addr)
{
        struct pgt_info *pgt_info = get_pgt_info(ctx, hop_addr);

        _free_hop(ctx, pgt_info);
}

static u64 alloc_hop(struct hl_ctx *ctx)
{
        struct hl_device *hdev = ctx->hdev;
        struct asic_fixed_properties *prop = &hdev->asic_prop;
        struct pgt_info *pgt_info;
        u64 phys_addr, shadow_addr;

        pgt_info = kmalloc(sizeof(*pgt_info), GFP_KERNEL);
        if (!pgt_info)
                return ULLONG_MAX;

        phys_addr = (u64) gen_pool_alloc(hdev->mmu_pgt_pool,
                                        prop->mmu_hop_table_size);
        if (!phys_addr) {
                dev_err(hdev->dev, "failed to allocate page\n");
                goto pool_add_err;
        }

        shadow_addr = (u64) (uintptr_t) kzalloc(prop->mmu_hop_table_size,
                                                GFP_KERNEL);
        if (!shadow_addr)
                goto shadow_err;

        pgt_info->phys_addr = phys_addr;
        pgt_info->shadow_addr = shadow_addr;
        pgt_info->ctx = ctx;
        pgt_info->num_of_ptes = 0;
        hash_add(ctx->mmu_shadow_hash, &pgt_info->node, shadow_addr);

        return shadow_addr;

shadow_err:
        gen_pool_free(hdev->mmu_pgt_pool, phys_addr, prop->mmu_hop_table_size);
pool_add_err:
        kfree(pgt_info);

        return ULLONG_MAX;
}

static inline u64 get_phys_hop0_addr(struct hl_ctx *ctx)
{
        return ctx->hdev->asic_prop.mmu_pgt_addr +
                        (ctx->asid * ctx->hdev->asic_prop.mmu_hop_table_size);
}

static inline u64 get_hop0_addr(struct hl_ctx *ctx)
{
        return (u64) (uintptr_t) ctx->hdev->mmu_shadow_hop0 +
                        (ctx->asid * ctx->hdev->asic_prop.mmu_hop_table_size);
}

static inline void flush(struct hl_ctx *ctx)
{
        /* flush all writes from all cores to reach PCI */
        mb();
        ctx->hdev->asic_funcs->read_pte(ctx->hdev, get_phys_hop0_addr(ctx));
}

/* transform the value to physical address when writing to H/W */
static inline void write_pte(struct hl_ctx *ctx, u64 shadow_pte_addr, u64 val)
{
        /*
         * The value to write is actually the address of the next shadow hop +
         * flags at the 12 LSBs.
         * Hence in order to get the value to write to the physical PTE, we
         * clear the 12 LSBs and translate the shadow hop to its associated
         * physical hop, and add back the original 12 LSBs.
         */
        u64 phys_val = get_phys_addr(ctx, val & HOP_PHYS_ADDR_MASK) |
                                (val & FLAGS_MASK);

        ctx->hdev->asic_funcs->write_pte(ctx->hdev,
                                        get_phys_addr(ctx, shadow_pte_addr),
                                        phys_val);

        *(u64 *) (uintptr_t) shadow_pte_addr = val;
}

/* do not transform the value to physical address when writing to H/W */
static inline void write_final_pte(struct hl_ctx *ctx, u64 shadow_pte_addr,
                                        u64 val)
{
        ctx->hdev->asic_funcs->write_pte(ctx->hdev,
                                        get_phys_addr(ctx, shadow_pte_addr),
                                        val);
        *(u64 *) (uintptr_t) shadow_pte_addr = val;
}

/* clear the last and present bits */
static inline void clear_pte(struct hl_ctx *ctx, u64 pte_addr)
{
        /* no need to transform the value to physical address */
        write_final_pte(ctx, pte_addr, 0);
}

static inline void get_pte(struct hl_ctx *ctx, u64 hop_addr)
{
        get_pgt_info(ctx, hop_addr)->num_of_ptes++;
}

/*
 * put_pte - decrement the num of ptes and free the hop if possible
 *
 * @ctx: pointer to the context structure
 * @hop_addr: addr of the hop
 *
 * This function returns the number of ptes left on this hop. If the number is
 * 0, it means the pte was freed.
 */
static inline int put_pte(struct hl_ctx *ctx, u64 hop_addr)
{
        struct pgt_info *pgt_info = get_pgt_info(ctx, hop_addr);
        int num_of_ptes_left;

        pgt_info->num_of_ptes--;

        /*
         * Need to save the number of ptes left because free_hop might free
         * the pgt_info
         */
        num_of_ptes_left = pgt_info->num_of_ptes;
        if (!num_of_ptes_left)
                _free_hop(ctx, pgt_info);

        return num_of_ptes_left;
}

static inline u64 get_hopN_pte_addr(struct hl_ctx *ctx, u64 hop_addr,
                                        u64 virt_addr, u64 mask, u64 shift)
{
        return hop_addr + ctx->hdev->asic_prop.mmu_pte_size *
                        ((virt_addr & mask) >> shift);
}

static inline u64 get_hop0_pte_addr(struct hl_ctx *ctx,
                                        struct hl_mmu_properties *mmu_prop,
                                        u64 hop_addr, u64 vaddr)
{
        return get_hopN_pte_addr(ctx, hop_addr, vaddr, mmu_prop->hop0_mask,
                                        mmu_prop->hop0_shift);
}

static inline u64 get_hop1_pte_addr(struct hl_ctx *ctx,
                                        struct hl_mmu_properties *mmu_prop,
                                        u64 hop_addr, u64 vaddr)
{
        return get_hopN_pte_addr(ctx, hop_addr, vaddr, mmu_prop->hop1_mask,
                                        mmu_prop->hop1_shift);
}

static inline u64 get_hop2_pte_addr(struct hl_ctx *ctx,
                                        struct hl_mmu_properties *mmu_prop,
                                        u64 hop_addr, u64 vaddr)
{
        return get_hopN_pte_addr(ctx, hop_addr, vaddr, mmu_prop->hop2_mask,
                                        mmu_prop->hop2_shift);
}

static inline u64 get_hop3_pte_addr(struct hl_ctx *ctx,
                                        struct hl_mmu_properties *mmu_prop,
                                        u64 hop_addr, u64 vaddr)
{
        return get_hopN_pte_addr(ctx, hop_addr, vaddr, mmu_prop->hop3_mask,
                                        mmu_prop->hop3_shift);
}

static inline u64 get_hop4_pte_addr(struct hl_ctx *ctx,
                                        struct hl_mmu_properties *mmu_prop,
                                        u64 hop_addr, u64 vaddr)
{
        return get_hopN_pte_addr(ctx, hop_addr, vaddr, mmu_prop->hop4_mask,
                                        mmu_prop->hop4_shift);
}

static inline u64 get_next_hop_addr(struct hl_ctx *ctx, u64 curr_pte)
{
        if (curr_pte & PAGE_PRESENT_MASK)
                return curr_pte & HOP_PHYS_ADDR_MASK;
        else
                return ULLONG_MAX;
}

static inline u64 get_alloc_next_hop_addr(struct hl_ctx *ctx, u64 curr_pte,
                                                bool *is_new_hop)
{
        u64 hop_addr = get_next_hop_addr(ctx, curr_pte);

        if (hop_addr == ULLONG_MAX) {
                hop_addr = alloc_hop(ctx);
                *is_new_hop = (hop_addr != ULLONG_MAX);
        }

        return hop_addr;
}

/* translates shadow address inside hop to a physical address */
static inline u64 get_phys_addr(struct hl_ctx *ctx, u64 shadow_addr)
{
        u64 page_mask = (ctx->hdev->asic_prop.mmu_hop_table_size - 1);
        u64 shadow_hop_addr = shadow_addr & ~page_mask;
        u64 pte_offset = shadow_addr & page_mask;
        u64 phys_hop_addr;

        if (shadow_hop_addr != get_hop0_addr(ctx))
                phys_hop_addr = get_pgt_info(ctx, shadow_hop_addr)->phys_addr;
        else
                phys_hop_addr = get_phys_hop0_addr(ctx);

        return phys_hop_addr + pte_offset;
}

static bool is_dram_va(struct hl_device *hdev, u64 virt_addr)
{
        struct asic_fixed_properties *prop = &hdev->asic_prop;

        return hl_mem_area_inside_range(virt_addr, prop->dmmu.page_size,
                                        prop->dmmu.start_addr,
                                        prop->dmmu.end_addr);
}

static int dram_default_mapping_init(struct hl_ctx *ctx)
{
        struct hl_device *hdev = ctx->hdev;
        struct asic_fixed_properties *prop = &hdev->asic_prop;
        u64 num_of_hop3, total_hops, hop0_addr, hop1_addr, hop2_addr,
                hop2_pte_addr, hop3_pte_addr, pte_val;
        int rc, i, j, hop3_allocated = 0;

        if ((!hdev->dram_supports_virtual_memory) ||
                        (!hdev->dram_default_page_mapping) ||
                        (ctx->asid == HL_KERNEL_ASID_ID))
                return 0;

        num_of_hop3 = prop->dram_size_for_default_page_mapping;
        do_div(num_of_hop3, prop->dram_page_size);
        do_div(num_of_hop3, PTE_ENTRIES_IN_HOP);

        /* add hop1 and hop2 */
        total_hops = num_of_hop3 + 2;

        ctx->dram_default_hops = kzalloc(HL_PTE_SIZE * total_hops,  GFP_KERNEL);
        if (!ctx->dram_default_hops)
                return -ENOMEM;

        hop0_addr = get_hop0_addr(ctx);

        hop1_addr = alloc_hop(ctx);
        if (hop1_addr == ULLONG_MAX) {
                dev_err(hdev->dev, "failed to alloc hop 1\n");
                rc = -ENOMEM;
                goto hop1_err;
        }

        ctx->dram_default_hops[total_hops - 1] = hop1_addr;

        hop2_addr = alloc_hop(ctx);
        if (hop2_addr == ULLONG_MAX) {
                dev_err(hdev->dev, "failed to alloc hop 2\n");
                rc = -ENOMEM;
                goto hop2_err;
        }

        ctx->dram_default_hops[total_hops - 2] = hop2_addr;

        for (i = 0 ; i < num_of_hop3 ; i++) {
                ctx->dram_default_hops[i] = alloc_hop(ctx);
                if (ctx->dram_default_hops[i] == ULLONG_MAX) {
                        dev_err(hdev->dev, "failed to alloc hop 3, i: %d\n", i);
                        rc = -ENOMEM;
                        goto hop3_err;
                }
                hop3_allocated++;
        }

        /* need only pte 0 in hops 0 and 1 */
        pte_val = (hop1_addr & HOP_PHYS_ADDR_MASK) | PAGE_PRESENT_MASK;
        write_pte(ctx, hop0_addr, pte_val);

        pte_val = (hop2_addr & HOP_PHYS_ADDR_MASK) | PAGE_PRESENT_MASK;
        write_pte(ctx, hop1_addr, pte_val);
        get_pte(ctx, hop1_addr);

        hop2_pte_addr = hop2_addr;
        for (i = 0 ; i < num_of_hop3 ; i++) {
                pte_val = (ctx->dram_default_hops[i] & HOP_PHYS_ADDR_MASK) |
                                PAGE_PRESENT_MASK;
                write_pte(ctx, hop2_pte_addr, pte_val);
                get_pte(ctx, hop2_addr);
                hop2_pte_addr += HL_PTE_SIZE;
        }

        pte_val = (prop->mmu_dram_default_page_addr & HOP_PHYS_ADDR_MASK) |
                        LAST_MASK | PAGE_PRESENT_MASK;

        for (i = 0 ; i < num_of_hop3 ; i++) {
                hop3_pte_addr = ctx->dram_default_hops[i];
                for (j = 0 ; j < PTE_ENTRIES_IN_HOP ; j++) {
                        write_final_pte(ctx, hop3_pte_addr, pte_val);
                        get_pte(ctx, ctx->dram_default_hops[i]);
                        hop3_pte_addr += HL_PTE_SIZE;
                }
        }

        flush(ctx);

        return 0;

hop3_err:
        for (i = 0 ; i < hop3_allocated ; i++)
                free_hop(ctx, ctx->dram_default_hops[i]);

        free_hop(ctx, hop2_addr);
hop2_err:
        free_hop(ctx, hop1_addr);
hop1_err:
        kfree(ctx->dram_default_hops);

        return rc;
}

static void dram_default_mapping_fini(struct hl_ctx *ctx)
{
        struct hl_device *hdev = ctx->hdev;
        struct asic_fixed_properties *prop = &hdev->asic_prop;
        u64 num_of_hop3, total_hops, hop0_addr, hop1_addr, hop2_addr,
                hop2_pte_addr, hop3_pte_addr;
        int i, j;

        if ((!hdev->dram_supports_virtual_memory) ||
                        (!hdev->dram_default_page_mapping) ||
                        (ctx->asid == HL_KERNEL_ASID_ID))
                return;

        num_of_hop3 = prop->dram_size_for_default_page_mapping;
        do_div(num_of_hop3, prop->dram_page_size);
        do_div(num_of_hop3, PTE_ENTRIES_IN_HOP);

        hop0_addr = get_hop0_addr(ctx);
        /* add hop1 and hop2 */
        total_hops = num_of_hop3 + 2;
        hop1_addr = ctx->dram_default_hops[total_hops - 1];
        hop2_addr = ctx->dram_default_hops[total_hops - 2];

        for (i = 0 ; i < num_of_hop3 ; i++) {
                hop3_pte_addr = ctx->dram_default_hops[i];
                for (j = 0 ; j < PTE_ENTRIES_IN_HOP ; j++) {
                        clear_pte(ctx, hop3_pte_addr);
                        put_pte(ctx, ctx->dram_default_hops[i]);
                        hop3_pte_addr += HL_PTE_SIZE;
                }
        }

        hop2_pte_addr = hop2_addr;
        hop2_pte_addr = hop2_addr;
        for (i = 0 ; i < num_of_hop3 ; i++) {
                clear_pte(ctx, hop2_pte_addr);
                put_pte(ctx, hop2_addr);
                hop2_pte_addr += HL_PTE_SIZE;
        }

        clear_pte(ctx, hop1_addr);
        put_pte(ctx, hop1_addr);
        clear_pte(ctx, hop0_addr);

        kfree(ctx->dram_default_hops);

        flush(ctx);
}

/**
 * hl_mmu_init() - initialize the MMU module.
 * @hdev: habanalabs device structure.
 *
 * This function does the following:
 * - Create a pool of pages for pgt_infos.
 * - Create a shadow table for pgt
 *
 * Return: 0 for success, non-zero for failure.
 */
int hl_mmu_init(struct hl_device *hdev)
{
        struct asic_fixed_properties *prop = &hdev->asic_prop;
        int rc;

        if (!hdev->mmu_enable)
                return 0;

        hdev->mmu_pgt_pool =
                        gen_pool_create(__ffs(prop->mmu_hop_table_size), -1);

        if (!hdev->mmu_pgt_pool) {
                dev_err(hdev->dev, "Failed to create page gen pool\n");
                return -ENOMEM;
        }

        rc = gen_pool_add(hdev->mmu_pgt_pool, prop->mmu_pgt_addr +
                        prop->mmu_hop0_tables_total_size,
                        prop->mmu_pgt_size - prop->mmu_hop0_tables_total_size,
                        -1);
        if (rc) {
                dev_err(hdev->dev, "Failed to add memory to page gen pool\n");
                goto err_pool_add;
        }

        hdev->mmu_shadow_hop0 = kvmalloc_array(prop->max_asid,
                                        prop->mmu_hop_table_size,
                                        GFP_KERNEL | __GFP_ZERO);
        if (ZERO_OR_NULL_PTR(hdev->mmu_shadow_hop0)) {
                rc = -ENOMEM;
                goto err_pool_add;
        }

        /* MMU H/W init will be done in device hw_init() */

        return 0;

err_pool_add:
        gen_pool_destroy(hdev->mmu_pgt_pool);

        return rc;
}

/**
 * hl_mmu_fini() - release the MMU module.
 * @hdev: habanalabs device structure.
 *
 * This function does the following:
 * - Disable MMU in H/W.
 * - Free the pgt_infos pool.
 *
 * All contexts should be freed before calling this function.
 */
void hl_mmu_fini(struct hl_device *hdev)
{
        if (!hdev->mmu_enable)
                return;

        /* MMU H/W fini was already done in device hw_fini() */

        kvfree(hdev->mmu_shadow_hop0);
        gen_pool_destroy(hdev->mmu_pgt_pool);
}

/**
 * hl_mmu_ctx_init() - initialize a context for using the MMU module.
 * @ctx: pointer to the context structure to initialize.
 *
 * Initialize a mutex to protect the concurrent mapping flow, a hash to hold all
 * page tables hops related to this context.
 * Return: 0 on success, non-zero otherwise.
 */
int hl_mmu_ctx_init(struct hl_ctx *ctx)
{
        struct hl_device *hdev = ctx->hdev;

        if (!hdev->mmu_enable)
                return 0;

        mutex_init(&ctx->mmu_lock);
        hash_init(ctx->mmu_shadow_hash);

        return dram_default_mapping_init(ctx);
}

/*
 * hl_mmu_ctx_fini - disable a ctx from using the mmu module
 *
 * @ctx: pointer to the context structure
 *
 * This function does the following:
 * - Free any pgts which were not freed yet
 * - Free the mutex
 * - Free DRAM default page mapping hops
 */
void hl_mmu_ctx_fini(struct hl_ctx *ctx)
{
        struct hl_device *hdev = ctx->hdev;
        struct pgt_info *pgt_info;
        struct hlist_node *tmp;
        int i;

        if (!hdev->mmu_enable)
                return;

        dram_default_mapping_fini(ctx);

        if (!hash_empty(ctx->mmu_shadow_hash))
                dev_err(hdev->dev, "ctx %d is freed while it has pgts in use\n",
                        ctx->asid);

        hash_for_each_safe(ctx->mmu_shadow_hash, i, tmp, pgt_info, node) {
                dev_err_ratelimited(hdev->dev,
                        "pgt_info of addr 0x%llx of asid %d was not destroyed, num_ptes: %d\n",
                        pgt_info->phys_addr, ctx->asid, pgt_info->num_of_ptes);
                _free_hop(ctx, pgt_info);
        }

        mutex_destroy(&ctx->mmu_lock);
}

static int _hl_mmu_unmap(struct hl_ctx *ctx, u64 virt_addr, bool is_dram_addr)
{
        struct hl_device *hdev = ctx->hdev;
        struct asic_fixed_properties *prop = &hdev->asic_prop;
        struct hl_mmu_properties *mmu_prop;
        u64 hop0_addr = 0, hop0_pte_addr = 0,
                hop1_addr = 0, hop1_pte_addr = 0,
                hop2_addr = 0, hop2_pte_addr = 0,
                hop3_addr = 0, hop3_pte_addr = 0,
                hop4_addr = 0, hop4_pte_addr = 0,
                curr_pte;
        bool is_huge, clear_hop3 = true;

        /* shifts and masks are the same in PMMU and HPMMU, use one of them */
        mmu_prop = is_dram_addr ? &prop->dmmu : &prop->pmmu;

        hop0_addr = get_hop0_addr(ctx);
        hop0_pte_addr = get_hop0_pte_addr(ctx, mmu_prop, hop0_addr, virt_addr);

        curr_pte = *(u64 *) (uintptr_t) hop0_pte_addr;

        hop1_addr = get_next_hop_addr(ctx, curr_pte);

        if (hop1_addr == ULLONG_MAX)
                goto not_mapped;

        hop1_pte_addr = get_hop1_pte_addr(ctx, mmu_prop, hop1_addr, virt_addr);

        curr_pte = *(u64 *) (uintptr_t) hop1_pte_addr;

        hop2_addr = get_next_hop_addr(ctx, curr_pte);

        if (hop2_addr == ULLONG_MAX)
                goto not_mapped;

        hop2_pte_addr = get_hop2_pte_addr(ctx, mmu_prop, hop2_addr, virt_addr);

        curr_pte = *(u64 *) (uintptr_t) hop2_pte_addr;

        hop3_addr = get_next_hop_addr(ctx, curr_pte);

        if (hop3_addr == ULLONG_MAX)
                goto not_mapped;

        hop3_pte_addr = get_hop3_pte_addr(ctx, mmu_prop, hop3_addr, virt_addr);

        curr_pte = *(u64 *) (uintptr_t) hop3_pte_addr;

        is_huge = curr_pte & LAST_MASK;

        if (is_dram_addr && !is_huge) {
                dev_err(hdev->dev,
                                "DRAM unmapping should use huge pages only\n");
                return -EFAULT;
        }

        if (!is_huge) {
                hop4_addr = get_next_hop_addr(ctx, curr_pte);

                if (hop4_addr == ULLONG_MAX)
                        goto not_mapped;

                hop4_pte_addr = get_hop4_pte_addr(ctx, mmu_prop, hop4_addr,
                                                        virt_addr);

                curr_pte = *(u64 *) (uintptr_t) hop4_pte_addr;

                clear_hop3 = false;
        }

        if (hdev->dram_default_page_mapping && is_dram_addr) {
                u64 default_pte = (prop->mmu_dram_default_page_addr &
                                HOP_PHYS_ADDR_MASK) | LAST_MASK |
                                        PAGE_PRESENT_MASK;
                if (curr_pte == default_pte) {
                        dev_err(hdev->dev,
                                "DRAM: hop3 PTE points to zero page, can't unmap, va: 0x%llx\n",
                                        virt_addr);
                        goto not_mapped;
                }

                if (!(curr_pte & PAGE_PRESENT_MASK)) {
                        dev_err(hdev->dev,
                                "DRAM: hop3 PTE is cleared! can't unmap, va: 0x%llx\n",
                                        virt_addr);
                        goto not_mapped;
                }

                write_final_pte(ctx, hop3_pte_addr, default_pte);
                put_pte(ctx, hop3_addr);
        } else {
                if (!(curr_pte & PAGE_PRESENT_MASK))
                        goto not_mapped;

                if (hop4_addr)
                        clear_pte(ctx, hop4_pte_addr);
                else
                        clear_pte(ctx, hop3_pte_addr);

                if (hop4_addr && !put_pte(ctx, hop4_addr))
                        clear_hop3 = true;

                if (!clear_hop3)
                        goto mapped;

                clear_pte(ctx, hop3_pte_addr);

                if (put_pte(ctx, hop3_addr))
                        goto mapped;

                clear_pte(ctx, hop2_pte_addr);

                if (put_pte(ctx, hop2_addr))
                        goto mapped;

                clear_pte(ctx, hop1_pte_addr);

                if (put_pte(ctx, hop1_addr))
                        goto mapped;

                clear_pte(ctx, hop0_pte_addr);
        }

mapped:
        return 0;

not_mapped:
        dev_err(hdev->dev, "virt addr 0x%llx is not mapped to phys addr\n",
                virt_addr);

        return -EINVAL;
}

/*
 * hl_mmu_unmap - unmaps a virtual addr
 *
 * @ctx: pointer to the context structure
 * @virt_addr: virt addr to map from
 * @page_size: size of the page to unmap
 * @flush_pte: whether to do a PCI flush
 *
 * This function does the following:
 * - Check that the virt addr is mapped
 * - Unmap the virt addr and frees pgts if possible
 * - Returns 0 on success, -EINVAL if the given addr is not mapped
 *
 * Because this function changes the page tables in the device and because it
 * changes the MMU hash, it must be protected by a lock.
 * However, because it maps only a single page, the lock should be implemented
 * in a higher level in order to protect the entire mapping of the memory area
 *
 * For optimization reasons PCI flush may be requested once after unmapping of
 * large area.
 */
int hl_mmu_unmap(struct hl_ctx *ctx, u64 virt_addr, u32 page_size,
                bool flush_pte)
{
        struct hl_device *hdev = ctx->hdev;
        struct asic_fixed_properties *prop = &hdev->asic_prop;
        struct hl_mmu_properties *mmu_prop;
        u64 real_virt_addr;
        u32 real_page_size, npages;
        int i, rc = 0;
        bool is_dram_addr;

        if (!hdev->mmu_enable)
                return 0;

        is_dram_addr = is_dram_va(hdev, virt_addr);

        if (is_dram_addr)
                mmu_prop = &prop->dmmu;
        else if ((page_size % prop->pmmu_huge.page_size) == 0)
                mmu_prop = &prop->pmmu_huge;
        else
                mmu_prop = &prop->pmmu;

        /*
         * The H/W handles mapping of specific page sizes. Hence if the page
         * size is bigger, we break it to sub-pages and unmap them separately.
         */
        if ((page_size % mmu_prop->page_size) == 0) {
                real_page_size = mmu_prop->page_size;
        } else {
                dev_err(hdev->dev,
                        "page size of %u is not %uKB aligned, can't unmap\n",
                        page_size, mmu_prop->page_size >> 10);

                return -EFAULT;
        }

        npages = page_size / real_page_size;
        real_virt_addr = virt_addr;

        for (i = 0 ; i < npages ; i++) {
                rc = _hl_mmu_unmap(ctx, real_virt_addr, is_dram_addr);
                if (rc)
                        break;

                real_virt_addr += real_page_size;
        }

        if (flush_pte)
                flush(ctx);

        return rc;
}

static int _hl_mmu_map(struct hl_ctx *ctx, u64 virt_addr, u64 phys_addr,
                        u32 page_size, bool is_dram_addr)
{
        struct hl_device *hdev = ctx->hdev;
        struct asic_fixed_properties *prop = &hdev->asic_prop;
        struct hl_mmu_properties *mmu_prop;
        u64 hop0_addr = 0, hop0_pte_addr = 0,
                hop1_addr = 0, hop1_pte_addr = 0,
                hop2_addr = 0, hop2_pte_addr = 0,
                hop3_addr = 0, hop3_pte_addr = 0,
                hop4_addr = 0, hop4_pte_addr = 0,
                curr_pte = 0;
        bool hop1_new = false, hop2_new = false, hop3_new = false,
                hop4_new = false, is_huge;
        int rc = -ENOMEM;

        /*
         * This mapping function can map a page or a huge page. For huge page
         * there are only 3 hops rather than 4. Currently the DRAM allocation
         * uses huge pages only but user memory could have been allocated with
         * one of the two page sizes. Since this is a common code for all the
         * three cases, we need this hugs page check.
         */
        if (is_dram_addr) {
                mmu_prop = &prop->dmmu;
                is_huge = true;
        } else if (page_size == prop->pmmu_huge.page_size) {
                mmu_prop = &prop->pmmu_huge;
                is_huge = true;
        } else {
                mmu_prop = &prop->pmmu;
                is_huge = false;
        }

        hop0_addr = get_hop0_addr(ctx);
        hop0_pte_addr = get_hop0_pte_addr(ctx, mmu_prop, hop0_addr, virt_addr);
        curr_pte = *(u64 *) (uintptr_t) hop0_pte_addr;

        hop1_addr = get_alloc_next_hop_addr(ctx, curr_pte, &hop1_new);
        if (hop1_addr == ULLONG_MAX)
                goto err;

        hop1_pte_addr = get_hop1_pte_addr(ctx, mmu_prop, hop1_addr, virt_addr);
        curr_pte = *(u64 *) (uintptr_t) hop1_pte_addr;

        hop2_addr = get_alloc_next_hop_addr(ctx, curr_pte, &hop2_new);
        if (hop2_addr == ULLONG_MAX)
                goto err;

        hop2_pte_addr = get_hop2_pte_addr(ctx, mmu_prop, hop2_addr, virt_addr);
        curr_pte = *(u64 *) (uintptr_t) hop2_pte_addr;

        hop3_addr = get_alloc_next_hop_addr(ctx, curr_pte, &hop3_new);
        if (hop3_addr == ULLONG_MAX)
                goto err;

        hop3_pte_addr = get_hop3_pte_addr(ctx, mmu_prop, hop3_addr, virt_addr);
        curr_pte = *(u64 *) (uintptr_t) hop3_pte_addr;

        if (!is_huge) {
                hop4_addr = get_alloc_next_hop_addr(ctx, curr_pte, &hop4_new);
                if (hop4_addr == ULLONG_MAX)
                        goto err;

                hop4_pte_addr = get_hop4_pte_addr(ctx, mmu_prop, hop4_addr,
                                                        virt_addr);
                curr_pte = *(u64 *) (uintptr_t) hop4_pte_addr;
        }

        if (hdev->dram_default_page_mapping && is_dram_addr) {
                u64 default_pte = (prop->mmu_dram_default_page_addr &
                                        HOP_PHYS_ADDR_MASK) | LAST_MASK |
                                                PAGE_PRESENT_MASK;

                if (curr_pte != default_pte) {
                        dev_err(hdev->dev,
                                "DRAM: mapping already exists for virt_addr 0x%llx\n",
                                        virt_addr);
                        rc = -EINVAL;
                        goto err;
                }

                if (hop1_new || hop2_new || hop3_new || hop4_new) {
                        dev_err(hdev->dev,
                                "DRAM mapping should not allocate more hops\n");
                        rc = -EFAULT;
                        goto err;
                }
        } else if (curr_pte & PAGE_PRESENT_MASK) {
                dev_err(hdev->dev,
                        "mapping already exists for virt_addr 0x%llx\n",
                                virt_addr);

                dev_dbg(hdev->dev, "hop0 pte: 0x%llx (0x%llx)\n",
                        *(u64 *) (uintptr_t) hop0_pte_addr, hop0_pte_addr);
                dev_dbg(hdev->dev, "hop1 pte: 0x%llx (0x%llx)\n",
                        *(u64 *) (uintptr_t) hop1_pte_addr, hop1_pte_addr);
                dev_dbg(hdev->dev, "hop2 pte: 0x%llx (0x%llx)\n",
                        *(u64 *) (uintptr_t) hop2_pte_addr, hop2_pte_addr);
                dev_dbg(hdev->dev, "hop3 pte: 0x%llx (0x%llx)\n",
                        *(u64 *) (uintptr_t) hop3_pte_addr, hop3_pte_addr);

                if (!is_huge)
                        dev_dbg(hdev->dev, "hop4 pte: 0x%llx (0x%llx)\n",
                                *(u64 *) (uintptr_t) hop4_pte_addr,
                                hop4_pte_addr);

                rc = -EINVAL;
                goto err;
        }

        curr_pte = (phys_addr & HOP_PHYS_ADDR_MASK) | LAST_MASK
                        | PAGE_PRESENT_MASK;

        if (is_huge)
                write_final_pte(ctx, hop3_pte_addr, curr_pte);
        else
                write_final_pte(ctx, hop4_pte_addr, curr_pte);

        if (hop1_new) {
                curr_pte =
                        (hop1_addr & HOP_PHYS_ADDR_MASK) | PAGE_PRESENT_MASK;
                write_pte(ctx, hop0_pte_addr, curr_pte);
        }
        if (hop2_new) {
                curr_pte =
                        (hop2_addr & HOP_PHYS_ADDR_MASK) | PAGE_PRESENT_MASK;
                write_pte(ctx, hop1_pte_addr, curr_pte);
                get_pte(ctx, hop1_addr);
        }
        if (hop3_new) {
                curr_pte =
                        (hop3_addr & HOP_PHYS_ADDR_MASK) | PAGE_PRESENT_MASK;
                write_pte(ctx, hop2_pte_addr, curr_pte);
                get_pte(ctx, hop2_addr);
        }

        if (!is_huge) {
                if (hop4_new) {
                        curr_pte = (hop4_addr & HOP_PHYS_ADDR_MASK) |
                                        PAGE_PRESENT_MASK;
                        write_pte(ctx, hop3_pte_addr, curr_pte);
                        get_pte(ctx, hop3_addr);
                }

                get_pte(ctx, hop4_addr);
        } else {
                get_pte(ctx, hop3_addr);
        }

        return 0;

err:
        if (hop4_new)
                free_hop(ctx, hop4_addr);
        if (hop3_new)
                free_hop(ctx, hop3_addr);
        if (hop2_new)
                free_hop(ctx, hop2_addr);
        if (hop1_new)
                free_hop(ctx, hop1_addr);

        return rc;
}

/*
 * hl_mmu_map - maps a virtual addr to physical addr
 *
 * @ctx: pointer to the context structure
 * @virt_addr: virt addr to map from
 * @phys_addr: phys addr to map to
 * @page_size: physical page size
 * @flush_pte: whether to do a PCI flush
 *
 * This function does the following:
 * - Check that the virt addr is not mapped
 * - Allocate pgts as necessary in order to map the virt addr to the phys
 * - Returns 0 on success, -EINVAL if addr is already mapped, or -ENOMEM.
 *
 * Because this function changes the page tables in the device and because it
 * changes the MMU hash, it must be protected by a lock.
 * However, because it maps only a single page, the lock should be implemented
 * in a higher level in order to protect the entire mapping of the memory area
 *
 * For optimization reasons PCI flush may be requested once after mapping of
 * large area.
 */
int hl_mmu_map(struct hl_ctx *ctx, u64 virt_addr, u64 phys_addr, u32 page_size,
                bool flush_pte)
{
        struct hl_device *hdev = ctx->hdev;
        struct asic_fixed_properties *prop = &hdev->asic_prop;
        struct hl_mmu_properties *mmu_prop;
        u64 real_virt_addr, real_phys_addr;
        u32 real_page_size, npages;
        int i, rc, mapped_cnt = 0;
        bool is_dram_addr;

        if (!hdev->mmu_enable)
                return 0;

        is_dram_addr = is_dram_va(hdev, virt_addr);

        if (is_dram_addr)
                mmu_prop = &prop->dmmu;
        else if ((page_size % prop->pmmu_huge.page_size) == 0)
                mmu_prop = &prop->pmmu_huge;
        else
                mmu_prop = &prop->pmmu;

        /*
         * The H/W handles mapping of specific page sizes. Hence if the page
         * size is bigger, we break it to sub-pages and map them separately.
         */
        if ((page_size % mmu_prop->page_size) == 0) {
                real_page_size = mmu_prop->page_size;
        } else {
                dev_err(hdev->dev,
                        "page size of %u is not %uKB aligned, can't unmap\n",
                        page_size, mmu_prop->page_size >> 10);

                return -EFAULT;
        }

        WARN_ONCE((phys_addr & (real_page_size - 1)),
                "Mapping 0x%llx with page size of 0x%x is erroneous! Address must be divisible by page size",
                phys_addr, real_page_size);

        npages = page_size / real_page_size;
        real_virt_addr = virt_addr;
        real_phys_addr = phys_addr;

        for (i = 0 ; i < npages ; i++) {
                rc = _hl_mmu_map(ctx, real_virt_addr, real_phys_addr,
                                real_page_size, is_dram_addr);
                if (rc)
                        goto err;

                real_virt_addr += real_page_size;
                real_phys_addr += real_page_size;
                mapped_cnt++;
        }

        if (flush_pte)
                flush(ctx);

        return 0;

err:
        real_virt_addr = virt_addr;
        for (i = 0 ; i < mapped_cnt ; i++) {
                if (_hl_mmu_unmap(ctx, real_virt_addr, is_dram_addr))
                        dev_warn_ratelimited(hdev->dev,
                                "failed to unmap va: 0x%llx\n", real_virt_addr);

                real_virt_addr += real_page_size;
        }

        flush(ctx);

        return rc;
}

/*
 * hl_mmu_swap_out - marks all mapping of the given ctx as swapped out
 *
 * @ctx: pointer to the context structure
 *
 */
void hl_mmu_swap_out(struct hl_ctx *ctx)
{

}

/*
 * hl_mmu_swap_in - marks all mapping of the given ctx as swapped in
 *
 * @ctx: pointer to the context structure
 *
 */
void hl_mmu_swap_in(struct hl_ctx *ctx)
{

}