/*
 * Copyright 2010 Red Hat Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: Ben Skeggs
 */
#include "ummu.h"
#include "vmm.h"

#include <subdev/bar.h>
#include <subdev/fb.h>

#include <nvif/if500d.h>
#include <nvif/if900d.h>

struct nvkm_mmu_ptp {
        struct nvkm_mmu_pt *pt;
        struct list_head head;
        u8  shift;
        u16 mask;
        u16 free;
};

static void
nvkm_mmu_ptp_put(struct nvkm_mmu *mmu, bool force, struct nvkm_mmu_pt *pt)
{
        const int slot = pt->base >> pt->ptp->shift;
        struct nvkm_mmu_ptp *ptp = pt->ptp;

        /* If there were no free slots in the parent allocation before,
         * there will be now, so return PTP to the cache.
         */
        if (!ptp->free)
                list_add(&ptp->head, &mmu->ptp.list);
        ptp->free |= BIT(slot);

        /* If there's no more sub-allocations, destroy PTP. */
        if (ptp->free == ptp->mask) {
                nvkm_mmu_ptc_put(mmu, force, &ptp->pt);
                list_del(&ptp->head);
                kfree(ptp);
        }

        kfree(pt);
}

static struct nvkm_mmu_pt *
nvkm_mmu_ptp_get(struct nvkm_mmu *mmu, u32 size, bool zero)
{
        struct nvkm_mmu_pt *pt;
        struct nvkm_mmu_ptp *ptp;
        int slot;

        if (!(pt = kzalloc(sizeof(*pt), GFP_KERNEL)))
                return NULL;

        ptp = list_first_entry_or_null(&mmu->ptp.list, typeof(*ptp), head);
        if (!ptp) {
                /* Need to allocate a new parent to sub-allocate from. */
                if (!(ptp = kmalloc(sizeof(*ptp), GFP_KERNEL))) {
                        kfree(pt);
                        return NULL;
                }

                ptp->pt = nvkm_mmu_ptc_get(mmu, 0x1000, 0x1000, false);
                if (!ptp->pt) {
                        kfree(ptp);
                        kfree(pt);
                        return NULL;
                }

                ptp->shift = order_base_2(size);
                slot = nvkm_memory_size(ptp->pt->memory) >> ptp->shift;
                ptp->mask = (1 << slot) - 1;
                ptp->free = ptp->mask;
                list_add(&ptp->head, &mmu->ptp.list);
        }
        pt->ptp = ptp;
        pt->sub = true;

        /* Sub-allocate from parent object, removing PTP from cache
         * if there's no more free slots left.
         */
        slot = __ffs(ptp->free);
        ptp->free &= ~BIT(slot);
        if (!ptp->free)
                list_del(&ptp->head);

        pt->memory = pt->ptp->pt->memory;
        pt->base = slot << ptp->shift;
        pt->addr = pt->ptp->pt->addr + pt->base;
        return pt;
}

struct nvkm_mmu_ptc {
        struct list_head head;
        struct list_head item;
        u32 size;
        u32 refs;
};

static inline struct nvkm_mmu_ptc *
nvkm_mmu_ptc_find(struct nvkm_mmu *mmu, u32 size)
{
        struct nvkm_mmu_ptc *ptc;

        list_for_each_entry(ptc, &mmu->ptc.list, head) {
                if (ptc->size == size)
                        return ptc;
        }

        ptc = kmalloc(sizeof(*ptc), GFP_KERNEL);
        if (ptc) {
                INIT_LIST_HEAD(&ptc->item);
                ptc->size = size;
                ptc->refs = 0;
                list_add(&ptc->head, &mmu->ptc.list);
        }

        return ptc;
}

void
nvkm_mmu_ptc_put(struct nvkm_mmu *mmu, bool force, struct nvkm_mmu_pt **ppt)
{
        struct nvkm_mmu_pt *pt = *ppt;
        if (pt) {
                /* Handle sub-allocated page tables. */
                if (pt->sub) {
                        mutex_lock(&mmu->ptp.mutex);
                        nvkm_mmu_ptp_put(mmu, force, pt);
                        mutex_unlock(&mmu->ptp.mutex);
                        return;
                }

                /* Either cache or free the object. */
                mutex_lock(&mmu->ptc.mutex);
                if (pt->ptc->refs < 8 /* Heuristic. */ && !force) {
                        list_add_tail(&pt->head, &pt->ptc->item);
                        pt->ptc->refs++;
                } else {
                        nvkm_memory_unref(&pt->memory);
                        kfree(pt);
                }
                mutex_unlock(&mmu->ptc.mutex);
        }
}

struct nvkm_mmu_pt *
nvkm_mmu_ptc_get(struct nvkm_mmu *mmu, u32 size, u32 align, bool zero)
{
        struct nvkm_mmu_ptc *ptc;
        struct nvkm_mmu_pt *pt;
        int ret;

        /* Sub-allocated page table (ie. GP100 LPT). */
        if (align < 0x1000) {
                mutex_lock(&mmu->ptp.mutex);
                pt = nvkm_mmu_ptp_get(mmu, align, zero);
                mutex_unlock(&mmu->ptp.mutex);
                return pt;
        }

        /* Lookup cache for this page table size. */
        mutex_lock(&mmu->ptc.mutex);
        ptc = nvkm_mmu_ptc_find(mmu, size);
        if (!ptc) {
                mutex_unlock(&mmu->ptc.mutex);
                return NULL;
        }

        /* If there's a free PT in the cache, reuse it. */
        pt = list_first_entry_or_null(&ptc->item, typeof(*pt), head);
        if (pt) {
                if (zero)
                        nvkm_fo64(pt->memory, 0, 0, size >> 3);
                list_del(&pt->head);
                ptc->refs--;
                mutex_unlock(&mmu->ptc.mutex);
                return pt;
        }
        mutex_unlock(&mmu->ptc.mutex);

        /* No such luck, we need to allocate. */
        if (!(pt = kmalloc(sizeof(*pt), GFP_KERNEL)))
                return NULL;
        pt->ptc = ptc;
        pt->sub = false;

        ret = nvkm_memory_new(mmu->subdev.device, NVKM_MEM_TARGET_INST,
                              size, align, zero, &pt->memory);
        if (ret) {
                kfree(pt);
                return NULL;
        }

        pt->base = 0;
        pt->addr = nvkm_memory_addr(pt->memory);
        return pt;
}

void
nvkm_mmu_ptc_dump(struct nvkm_mmu *mmu)
{
        struct nvkm_mmu_ptc *ptc;
        list_for_each_entry(ptc, &mmu->ptc.list, head) {
                struct nvkm_mmu_pt *pt, *tt;
                list_for_each_entry_safe(pt, tt, &ptc->item, head) {
                        nvkm_memory_unref(&pt->memory);
                        list_del(&pt->head);
                        kfree(pt);
                }
        }
}

static void
nvkm_mmu_ptc_fini(struct nvkm_mmu *mmu)
{
        struct nvkm_mmu_ptc *ptc, *ptct;

        list_for_each_entry_safe(ptc, ptct, &mmu->ptc.list, head) {
                WARN_ON(!list_empty(&ptc->item));
                list_del(&ptc->head);
                kfree(ptc);
        }
}

static void
nvkm_mmu_ptc_init(struct nvkm_mmu *mmu)
{
        mutex_init(&mmu->ptc.mutex);
        INIT_LIST_HEAD(&mmu->ptc.list);
        mutex_init(&mmu->ptp.mutex);
        INIT_LIST_HEAD(&mmu->ptp.list);
}

static void
nvkm_mmu_type(struct nvkm_mmu *mmu, int heap, u8 type)
{
        if (heap >= 0 && !WARN_ON(mmu->type_nr == ARRAY_SIZE(mmu->type))) {
                mmu->type[mmu->type_nr].type = type | mmu->heap[heap].type;
                mmu->type[mmu->type_nr].heap = heap;
                mmu->type_nr++;
        }
}

static int
nvkm_mmu_heap(struct nvkm_mmu *mmu, u8 type, u64 size)
{
        if (size) {
                if (!WARN_ON(mmu->heap_nr == ARRAY_SIZE(mmu->heap))) {
                        mmu->heap[mmu->heap_nr].type = type;
                        mmu->heap[mmu->heap_nr].size = size;
                        return mmu->heap_nr++;
                }
        }
        return -EINVAL;
}

static void
nvkm_mmu_host(struct nvkm_mmu *mmu)
{
        struct nvkm_device *device = mmu->subdev.device;
        u8 type = NVKM_MEM_KIND * !!mmu->func->kind_sys;
        int heap;

        /* Non-mappable system memory. */
        heap = nvkm_mmu_heap(mmu, NVKM_MEM_HOST, ~0ULL);
        nvkm_mmu_type(mmu, heap, type);

        /* Non-coherent, cached, system memory.
         *
         * Block-linear mappings of system memory must be done through
         * BAR1, and cannot be supported on systems where we're unable
         * to map BAR1 with write-combining.
         */
        type |= NVKM_MEM_MAPPABLE;
        if (!device->bar || device->bar->iomap_uncached)
                nvkm_mmu_type(mmu, heap, type & ~NVKM_MEM_KIND);
        else
                nvkm_mmu_type(mmu, heap, type);

        /* Coherent, cached, system memory.
         *
         * Unsupported on systems that aren't able to support snooped
         * mappings, and also for block-linear mappings which must be
         * done through BAR1.
         */
        type |= NVKM_MEM_COHERENT;
        if (device->func->cpu_coherent)
                nvkm_mmu_type(mmu, heap, type & ~NVKM_MEM_KIND);

        /* Uncached system memory. */
        nvkm_mmu_type(mmu, heap, type |= NVKM_MEM_UNCACHED);
}

static void
nvkm_mmu_vram(struct nvkm_mmu *mmu)
{
        struct nvkm_device *device = mmu->subdev.device;
        struct nvkm_mm *mm = &device->fb->ram->vram;
        const u64 sizeN = nvkm_mm_heap_size(mm, NVKM_RAM_MM_NORMAL);
        const u64 sizeU = nvkm_mm_heap_size(mm, NVKM_RAM_MM_NOMAP);
        const u64 sizeM = nvkm_mm_heap_size(mm, NVKM_RAM_MM_MIXED);
        u8 type = NVKM_MEM_KIND * !!mmu->func->kind;
        u8 heap = NVKM_MEM_VRAM;
        int heapM, heapN, heapU;

        /* Mixed-memory doesn't support compression or display. */
        heapM = nvkm_mmu_heap(mmu, heap, sizeM << NVKM_RAM_MM_SHIFT);

        heap |= NVKM_MEM_COMP;
        heap |= NVKM_MEM_DISP;
        heapN = nvkm_mmu_heap(mmu, heap, sizeN << NVKM_RAM_MM_SHIFT);
        heapU = nvkm_mmu_heap(mmu, heap, sizeU << NVKM_RAM_MM_SHIFT);

        /* Add non-mappable VRAM types first so that they're preferred
         * over anything else.  Mixed-memory will be slower than other
         * heaps, it's prioritised last.
         */
        nvkm_mmu_type(mmu, heapU, type);
        nvkm_mmu_type(mmu, heapN, type);
        nvkm_mmu_type(mmu, heapM, type);

        /* Add host memory types next, under the assumption that users
         * wanting mappable memory want to use them as staging buffers
         * or the like.
         */
        nvkm_mmu_host(mmu);

        /* Mappable VRAM types go last, as they're basically the worst
         * possible type to ask for unless there's no other choice.
         */
        if (device->bar) {
                /* Write-combined BAR1 access. */
                type |= NVKM_MEM_MAPPABLE;
                if (!device->bar->iomap_uncached) {
                        nvkm_mmu_type(mmu, heapN, type);
                        nvkm_mmu_type(mmu, heapM, type);
                }

                /* Uncached BAR1 access. */
                type |= NVKM_MEM_COHERENT;
                type |= NVKM_MEM_UNCACHED;
                nvkm_mmu_type(mmu, heapN, type);
                nvkm_mmu_type(mmu, heapM, type);
        }
}

static int
nvkm_mmu_oneinit(struct nvkm_subdev *subdev)
{
        struct nvkm_mmu *mmu = nvkm_mmu(subdev);

        /* Determine available memory types. */
        if (mmu->subdev.device->fb && mmu->subdev.device->fb->ram)
                nvkm_mmu_vram(mmu);
        else
                nvkm_mmu_host(mmu);

        if (mmu->func->vmm.global) {
                int ret = nvkm_vmm_new(subdev->device, 0, 0, NULL, 0, NULL,
                                       "gart", &mmu->vmm);
                if (ret)
                        return ret;
        }

        return 0;
}

static int
nvkm_mmu_init(struct nvkm_subdev *subdev)
{
        struct nvkm_mmu *mmu = nvkm_mmu(subdev);
        if (mmu->func->init)
                mmu->func->init(mmu);
        return 0;
}

static void *
nvkm_mmu_dtor(struct nvkm_subdev *subdev)
{
        struct nvkm_mmu *mmu = nvkm_mmu(subdev);

        nvkm_vmm_unref(&mmu->vmm);

        nvkm_mmu_ptc_fini(mmu);
        mutex_destroy(&mmu->mutex);
        return mmu;
}

static const struct nvkm_subdev_func
nvkm_mmu = {
        .dtor = nvkm_mmu_dtor,
        .oneinit = nvkm_mmu_oneinit,
        .init = nvkm_mmu_init,
};

void
nvkm_mmu_ctor(const struct nvkm_mmu_func *func, struct nvkm_device *device,
              enum nvkm_subdev_type type, int inst, struct nvkm_mmu *mmu)
{
        nvkm_subdev_ctor(&nvkm_mmu, device, type, inst, &mmu->subdev);
        mmu->func = func;
        mmu->dma_bits = func->dma_bits;
        nvkm_mmu_ptc_init(mmu);
        mutex_init(&mmu->mutex);
        mmu->user.ctor = nvkm_ummu_new;
        mmu->user.base = func->mmu.user;
}

int
nvkm_mmu_new_(const struct nvkm_mmu_func *func, struct nvkm_device *device,
              enum nvkm_subdev_type type, int inst, struct nvkm_mmu **pmmu)
{
        if (!(*pmmu = kzalloc(sizeof(**pmmu), GFP_KERNEL)))
                return -ENOMEM;
        nvkm_mmu_ctor(func, device, type, inst, *pmmu);
        return 0;
}