// SPDX-License-Identifier: MIT
/*
 * Copyright © 2020 Intel Corporation
 */

#include <linux/slab.h>

#include "i915_trace.h"
#include "intel_gtt.h"
#include "gen6_ppgtt.h"
#include "gen8_ppgtt.h"

struct i915_page_table *alloc_pt(struct i915_address_space *vm)
{
        struct i915_page_table *pt;

        pt = kmalloc(sizeof(*pt), I915_GFP_ALLOW_FAIL);
        if (unlikely(!pt))
                return ERR_PTR(-ENOMEM);

        pt->base = vm->alloc_pt_dma(vm, I915_GTT_PAGE_SIZE_4K);
        if (IS_ERR(pt->base)) {
                kfree(pt);
                return ERR_PTR(-ENOMEM);
        }

        atomic_set(&pt->used, 0);
        return pt;
}

struct i915_page_directory *__alloc_pd(int count)
{
        struct i915_page_directory *pd;

        pd = kzalloc(sizeof(*pd), I915_GFP_ALLOW_FAIL);
        if (unlikely(!pd))
                return NULL;

        pd->entry = kcalloc(count, sizeof(*pd->entry), I915_GFP_ALLOW_FAIL);
        if (unlikely(!pd->entry)) {
                kfree(pd);
                return NULL;
        }

        spin_lock_init(&pd->lock);
        return pd;
}

struct i915_page_directory *alloc_pd(struct i915_address_space *vm)
{
        struct i915_page_directory *pd;

        pd = __alloc_pd(I915_PDES);
        if (unlikely(!pd))
                return ERR_PTR(-ENOMEM);

        pd->pt.base = vm->alloc_pt_dma(vm, I915_GTT_PAGE_SIZE_4K);
        if (IS_ERR(pd->pt.base)) {
                kfree(pd->entry);
                kfree(pd);
                return ERR_PTR(-ENOMEM);
        }

        return pd;
}

void free_px(struct i915_address_space *vm, struct i915_page_table *pt, int lvl)
{
        BUILD_BUG_ON(offsetof(struct i915_page_directory, pt));

        if (lvl) {
                struct i915_page_directory *pd =
                        container_of(pt, typeof(*pd), pt);
                kfree(pd->entry);
        }

        if (pt->base)
                i915_gem_object_put(pt->base);

        kfree(pt);
}

static void
write_dma_entry(struct drm_i915_gem_object * const pdma,
                const unsigned short idx,
                const u64 encoded_entry)
{
        u64 * const vaddr = kmap_atomic(__px_page(pdma));

        vaddr[idx] = encoded_entry;
        clflush_cache_range(&vaddr[idx], sizeof(u64));
        kunmap_atomic(vaddr);
}

void
__set_pd_entry(struct i915_page_directory * const pd,
               const unsigned short idx,
               struct i915_page_table * const to,
               u64 (*encode)(const dma_addr_t, const enum i915_cache_level))
{
        /* Each thread pre-pins the pd, and we may have a thread per pde. */
        GEM_BUG_ON(atomic_read(px_used(pd)) > NALLOC * I915_PDES);

        atomic_inc(px_used(pd));
        pd->entry[idx] = to;
        write_dma_entry(px_base(pd), idx, encode(px_dma(to), I915_CACHE_LLC));
}

void
clear_pd_entry(struct i915_page_directory * const pd,
               const unsigned short idx,
               const struct drm_i915_gem_object * const scratch)
{
        GEM_BUG_ON(atomic_read(px_used(pd)) == 0);

        write_dma_entry(px_base(pd), idx, scratch->encode);
        pd->entry[idx] = NULL;
        atomic_dec(px_used(pd));
}

bool
release_pd_entry(struct i915_page_directory * const pd,
                 const unsigned short idx,
                 struct i915_page_table * const pt,
                 const struct drm_i915_gem_object * const scratch)
{
        bool free = false;

        if (atomic_add_unless(&pt->used, -1, 1))
                return false;

        spin_lock(&pd->lock);
        if (atomic_dec_and_test(&pt->used)) {
                clear_pd_entry(pd, idx, scratch);
                free = true;
        }
        spin_unlock(&pd->lock);

        return free;
}

int i915_ppgtt_init_hw(struct intel_gt *gt)
{
        struct drm_i915_private *i915 = gt->i915;

        gtt_write_workarounds(gt);

        if (IS_GEN(i915, 6))
                gen6_ppgtt_enable(gt);
        else if (IS_GEN(i915, 7))
                gen7_ppgtt_enable(gt);

        return 0;
}

static struct i915_ppgtt *
__ppgtt_create(struct intel_gt *gt)
{
        if (INTEL_GEN(gt->i915) < 8)
                return gen6_ppgtt_create(gt);
        else
                return gen8_ppgtt_create(gt);
}

struct i915_ppgtt *i915_ppgtt_create(struct intel_gt *gt)
{
        struct i915_ppgtt *ppgtt;

        ppgtt = __ppgtt_create(gt);
        if (IS_ERR(ppgtt))
                return ppgtt;

        trace_i915_ppgtt_create(&ppgtt->vm);

        return ppgtt;
}

void ppgtt_bind_vma(struct i915_address_space *vm,
                    struct i915_vm_pt_stash *stash,
                    struct i915_vma *vma,
                    enum i915_cache_level cache_level,
                    u32 flags)
{
        u32 pte_flags;

        if (!test_bit(I915_VMA_ALLOC_BIT, __i915_vma_flags(vma))) {
                vm->allocate_va_range(vm, stash, vma->node.start, vma->size);
                set_bit(I915_VMA_ALLOC_BIT, __i915_vma_flags(vma));
        }

        /* Applicable to VLV, and gen8+ */
        pte_flags = 0;
        if (i915_gem_object_is_readonly(vma->obj))
                pte_flags |= PTE_READ_ONLY;

        vm->insert_entries(vm, vma, cache_level, pte_flags);
        wmb();
}

void ppgtt_unbind_vma(struct i915_address_space *vm, struct i915_vma *vma)
{
        if (test_and_clear_bit(I915_VMA_ALLOC_BIT, __i915_vma_flags(vma)))
                vm->clear_range(vm, vma->node.start, vma->size);
}

static unsigned long pd_count(u64 size, int shift)
{
        /* Beware later misalignment */
        return (size + 2 * (BIT_ULL(shift) - 1)) >> shift;
}

int i915_vm_alloc_pt_stash(struct i915_address_space *vm,
                           struct i915_vm_pt_stash *stash,
                           u64 size)
{
        unsigned long count;
        int shift, n;

        shift = vm->pd_shift;
        if (!shift)
                return 0;

        count = pd_count(size, shift);
        while (count--) {
                struct i915_page_table *pt;

                pt = alloc_pt(vm);
                if (IS_ERR(pt)) {
                        i915_vm_free_pt_stash(vm, stash);
                        return PTR_ERR(pt);
                }

                pt->stash = stash->pt[0];
                stash->pt[0] = pt;
        }

        for (n = 1; n < vm->top; n++) {
                shift += ilog2(I915_PDES); /* Each PD holds 512 entries */
                count = pd_count(size, shift);
                while (count--) {
                        struct i915_page_directory *pd;

                        pd = alloc_pd(vm);
                        if (IS_ERR(pd)) {
                                i915_vm_free_pt_stash(vm, stash);
                                return PTR_ERR(pd);
                        }

                        pd->pt.stash = stash->pt[1];
                        stash->pt[1] = &pd->pt;
                }
        }

        return 0;
}

int i915_vm_pin_pt_stash(struct i915_address_space *vm,
                         struct i915_vm_pt_stash *stash)
{
        struct i915_page_table *pt;
        int n, err;

        for (n = 0; n < ARRAY_SIZE(stash->pt); n++) {
                for (pt = stash->pt[n]; pt; pt = pt->stash) {
                        err = pin_pt_dma(vm, pt->base);
                        if (err)
                                return err;
                }
        }

        return 0;
}

void i915_vm_free_pt_stash(struct i915_address_space *vm,
                           struct i915_vm_pt_stash *stash)
{
        struct i915_page_table *pt;
        int n;

        for (n = 0; n < ARRAY_SIZE(stash->pt); n++) {
                while ((pt = stash->pt[n])) {
                        stash->pt[n] = pt->stash;
                        free_px(vm, pt, n);
                }
        }
}

int ppgtt_set_pages(struct i915_vma *vma)
{
        GEM_BUG_ON(vma->pages);

        vma->pages = vma->obj->mm.pages;
        vma->page_sizes = vma->obj->mm.page_sizes;

        return 0;
}

void ppgtt_init(struct i915_ppgtt *ppgtt, struct intel_gt *gt)
{
        struct drm_i915_private *i915 = gt->i915;

        ppgtt->vm.gt = gt;
        ppgtt->vm.i915 = i915;
        ppgtt->vm.dma = &i915->drm.pdev->dev;
        ppgtt->vm.total = BIT_ULL(INTEL_INFO(i915)->ppgtt_size);

        i915_address_space_init(&ppgtt->vm, VM_CLASS_PPGTT);

        ppgtt->vm.vma_ops.bind_vma    = ppgtt_bind_vma;
        ppgtt->vm.vma_ops.unbind_vma  = ppgtt_unbind_vma;
        ppgtt->vm.vma_ops.set_pages   = ppgtt_set_pages;
        ppgtt->vm.vma_ops.clear_pages = clear_pages;
}