/*
 * Copyright 2012 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
 */
#define nv50_instmem(p) container_of((p), struct nv50_instmem, base)
#include "priv.h"

#include <core/memory.h>
#include <subdev/bar.h>
#include <subdev/fb.h>
#include <subdev/mmu.h>

struct nv50_instmem {
        struct nvkm_instmem base;
        u64 addr;

        /* Mappings that can be evicted when BAR2 space has been exhausted. */
        struct list_head lru;
};

/******************************************************************************
 * instmem object implementation
 *****************************************************************************/
#define nv50_instobj(p) container_of((p), struct nv50_instobj, base.memory)

struct nv50_instobj {
        struct nvkm_instobj base;
        struct nv50_instmem *imem;
        struct nvkm_memory *ram;
        struct nvkm_vma *bar;
        refcount_t maps;
        void *map;
        struct list_head lru;
};

static void
nv50_instobj_wr32_slow(struct nvkm_memory *memory, u64 offset, u32 data)
{
        struct nv50_instobj *iobj = nv50_instobj(memory);
        struct nv50_instmem *imem = iobj->imem;
        struct nvkm_device *device = imem->base.subdev.device;
        u64 base = (nvkm_memory_addr(iobj->ram) + offset) & 0xffffff00000ULL;
        u64 addr = (nvkm_memory_addr(iobj->ram) + offset) & 0x000000fffffULL;
        unsigned long flags;

        spin_lock_irqsave(&imem->base.lock, flags);
        if (unlikely(imem->addr != base)) {
                nvkm_wr32(device, 0x001700, base >> 16);
                imem->addr = base;
        }
        nvkm_wr32(device, 0x700000 + addr, data);
        spin_unlock_irqrestore(&imem->base.lock, flags);
}

static u32
nv50_instobj_rd32_slow(struct nvkm_memory *memory, u64 offset)
{
        struct nv50_instobj *iobj = nv50_instobj(memory);
        struct nv50_instmem *imem = iobj->imem;
        struct nvkm_device *device = imem->base.subdev.device;
        u64 base = (nvkm_memory_addr(iobj->ram) + offset) & 0xffffff00000ULL;
        u64 addr = (nvkm_memory_addr(iobj->ram) + offset) & 0x000000fffffULL;
        u32 data;
        unsigned long flags;

        spin_lock_irqsave(&imem->base.lock, flags);
        if (unlikely(imem->addr != base)) {
                nvkm_wr32(device, 0x001700, base >> 16);
                imem->addr = base;
        }
        data = nvkm_rd32(device, 0x700000 + addr);
        spin_unlock_irqrestore(&imem->base.lock, flags);
        return data;
}

static const struct nvkm_memory_ptrs
nv50_instobj_slow = {
        .rd32 = nv50_instobj_rd32_slow,
        .wr32 = nv50_instobj_wr32_slow,
};

static void
nv50_instobj_wr32(struct nvkm_memory *memory, u64 offset, u32 data)
{
        iowrite32_native(data, nv50_instobj(memory)->map + offset);
}

static u32
nv50_instobj_rd32(struct nvkm_memory *memory, u64 offset)
{
        return ioread32_native(nv50_instobj(memory)->map + offset);
}

static const struct nvkm_memory_ptrs
nv50_instobj_fast = {
        .rd32 = nv50_instobj_rd32,
        .wr32 = nv50_instobj_wr32,
};

static void
nv50_instobj_kmap(struct nv50_instobj *iobj, struct nvkm_vmm *vmm)
{
        struct nv50_instmem *imem = iobj->imem;
        struct nv50_instobj *eobj;
        struct nvkm_memory *memory = &iobj->base.memory;
        struct nvkm_subdev *subdev = &imem->base.subdev;
        struct nvkm_device *device = subdev->device;
        struct nvkm_vma *bar = NULL, *ebar;
        u64 size = nvkm_memory_size(memory);
        void *emap;
        int ret;

        /* Attempt to allocate BAR2 address-space and map the object
         * into it.  The lock has to be dropped while doing this due
         * to the possibility of recursion for page table allocation.
         */
        mutex_unlock(&subdev->mutex);
        while ((ret = nvkm_vmm_get(vmm, 12, size, &bar))) {
                /* Evict unused mappings, and keep retrying until we either
                 * succeed,or there's no more objects left on the LRU.
                 */
                mutex_lock(&subdev->mutex);
                eobj = list_first_entry_or_null(&imem->lru, typeof(*eobj), lru);
                if (eobj) {
                        nvkm_debug(subdev, "evict %016llx %016llx @ %016llx\n",
                                   nvkm_memory_addr(&eobj->base.memory),
                                   nvkm_memory_size(&eobj->base.memory),
                                   eobj->bar->addr);
                        list_del_init(&eobj->lru);
                        ebar = eobj->bar;
                        eobj->bar = NULL;
                        emap = eobj->map;
                        eobj->map = NULL;
                }
                mutex_unlock(&subdev->mutex);
                if (!eobj)
                        break;
                iounmap(emap);
                nvkm_vmm_put(vmm, &ebar);
        }

        if (ret == 0)
                ret = nvkm_memory_map(memory, 0, vmm, bar, NULL, 0);
        mutex_lock(&subdev->mutex);
        if (ret || iobj->bar) {
                /* We either failed, or another thread beat us. */
                mutex_unlock(&subdev->mutex);
                nvkm_vmm_put(vmm, &bar);
                mutex_lock(&subdev->mutex);
                return;
        }

        /* Make the mapping visible to the host. */
        iobj->bar = bar;
        iobj->map = ioremap_wc(device->func->resource_addr(device, 3) +
                               (u32)iobj->bar->addr, size);
        if (!iobj->map) {
                nvkm_warn(subdev, "PRAMIN ioremap failed\n");
                nvkm_vmm_put(vmm, &iobj->bar);
        }
}

static int
nv50_instobj_map(struct nvkm_memory *memory, u64 offset, struct nvkm_vmm *vmm,
                 struct nvkm_vma *vma, void *argv, u32 argc)
{
        memory = nv50_instobj(memory)->ram;
        return nvkm_memory_map(memory, offset, vmm, vma, argv, argc);
}

static void
nv50_instobj_release(struct nvkm_memory *memory)
{
        struct nv50_instobj *iobj = nv50_instobj(memory);
        struct nv50_instmem *imem = iobj->imem;
        struct nvkm_subdev *subdev = &imem->base.subdev;

        wmb();
        nvkm_bar_flush(subdev->device->bar);

        if (refcount_dec_and_mutex_lock(&iobj->maps, &subdev->mutex)) {
                /* Add the now-unused mapping to the LRU instead of directly
                 * unmapping it here, in case we need to map it again later.
                 */
                if (likely(iobj->lru.next) && iobj->map) {
                        BUG_ON(!list_empty(&iobj->lru));
                        list_add_tail(&iobj->lru, &imem->lru);
                }

                /* Switch back to NULL accessors when last map is gone. */
                iobj->base.memory.ptrs = NULL;
                mutex_unlock(&subdev->mutex);
        }
}

static void __iomem *
nv50_instobj_acquire(struct nvkm_memory *memory)
{
        struct nv50_instobj *iobj = nv50_instobj(memory);
        struct nvkm_instmem *imem = &iobj->imem->base;
        struct nvkm_vmm *vmm;
        void __iomem *map = NULL;

        /* Already mapped? */
        if (refcount_inc_not_zero(&iobj->maps))
                return iobj->map;

        /* Take the lock, and re-check that another thread hasn't
         * already mapped the object in the meantime.
         */
        mutex_lock(&imem->subdev.mutex);
        if (refcount_inc_not_zero(&iobj->maps)) {
                mutex_unlock(&imem->subdev.mutex);
                return iobj->map;
        }

        /* Attempt to get a direct CPU mapping of the object. */
        if ((vmm = nvkm_bar_bar2_vmm(imem->subdev.device))) {
                if (!iobj->map)
                        nv50_instobj_kmap(iobj, vmm);
                map = iobj->map;
        }

        if (!refcount_inc_not_zero(&iobj->maps)) {
                /* Exclude object from eviction while it's being accessed. */
                if (likely(iobj->lru.next))
                        list_del_init(&iobj->lru);

                if (map)
                        iobj->base.memory.ptrs = &nv50_instobj_fast;
                else
                        iobj->base.memory.ptrs = &nv50_instobj_slow;
                refcount_set(&iobj->maps, 1);
        }

        mutex_unlock(&imem->subdev.mutex);
        return map;
}

static void
nv50_instobj_boot(struct nvkm_memory *memory, struct nvkm_vmm *vmm)
{
        struct nv50_instobj *iobj = nv50_instobj(memory);
        struct nvkm_instmem *imem = &iobj->imem->base;

        /* Exclude bootstrapped objects (ie. the page tables for the
         * instmem BAR itself) from eviction.
         */
        mutex_lock(&imem->subdev.mutex);
        if (likely(iobj->lru.next)) {
                list_del_init(&iobj->lru);
                iobj->lru.next = NULL;
        }

        nv50_instobj_kmap(iobj, vmm);
        nvkm_instmem_boot(imem);
        mutex_unlock(&imem->subdev.mutex);
}

static u64
nv50_instobj_size(struct nvkm_memory *memory)
{
        return nvkm_memory_size(nv50_instobj(memory)->ram);
}

static u64
nv50_instobj_addr(struct nvkm_memory *memory)
{
        return nvkm_memory_addr(nv50_instobj(memory)->ram);
}

static u64
nv50_instobj_bar2(struct nvkm_memory *memory)
{
        struct nv50_instobj *iobj = nv50_instobj(memory);
        u64 addr = ~0ULL;
        if (nv50_instobj_acquire(&iobj->base.memory)) {
                iobj->lru.next = NULL; /* Exclude from eviction. */
                addr = iobj->bar->addr;
        }
        nv50_instobj_release(&iobj->base.memory);
        return addr;
}

static enum nvkm_memory_target
nv50_instobj_target(struct nvkm_memory *memory)
{
        return nvkm_memory_target(nv50_instobj(memory)->ram);
}

static void *
nv50_instobj_dtor(struct nvkm_memory *memory)
{
        struct nv50_instobj *iobj = nv50_instobj(memory);
        struct nvkm_instmem *imem = &iobj->imem->base;
        struct nvkm_vma *bar;
        void *map = map;

        mutex_lock(&imem->subdev.mutex);
        if (likely(iobj->lru.next))
                list_del(&iobj->lru);
        map = iobj->map;
        bar = iobj->bar;
        mutex_unlock(&imem->subdev.mutex);

        if (map) {
                struct nvkm_vmm *vmm = nvkm_bar_bar2_vmm(imem->subdev.device);
                iounmap(map);
                if (likely(vmm)) /* Can be NULL during BAR destructor. */
                        nvkm_vmm_put(vmm, &bar);
        }

        nvkm_memory_unref(&iobj->ram);
        nvkm_instobj_dtor(imem, &iobj->base);
        return iobj;
}

static const struct nvkm_memory_func
nv50_instobj_func = {
        .dtor = nv50_instobj_dtor,
        .target = nv50_instobj_target,
        .bar2 = nv50_instobj_bar2,
        .addr = nv50_instobj_addr,
        .size = nv50_instobj_size,
        .boot = nv50_instobj_boot,
        .acquire = nv50_instobj_acquire,
        .release = nv50_instobj_release,
        .map = nv50_instobj_map,
};

static int
nv50_instobj_new(struct nvkm_instmem *base, u32 size, u32 align, bool zero,
                 struct nvkm_memory **pmemory)
{
        struct nv50_instmem *imem = nv50_instmem(base);
        struct nv50_instobj *iobj;
        struct nvkm_device *device = imem->base.subdev.device;
        u8 page = max(order_base_2(align), 12);

        if (!(iobj = kzalloc(sizeof(*iobj), GFP_KERNEL)))
                return -ENOMEM;
        *pmemory = &iobj->base.memory;

        nvkm_instobj_ctor(&nv50_instobj_func, &imem->base, &iobj->base);
        iobj->imem = imem;
        refcount_set(&iobj->maps, 0);
        INIT_LIST_HEAD(&iobj->lru);

        return nvkm_ram_get(device, 0, 1, page, size, true, true, &iobj->ram);
}

/******************************************************************************
 * instmem subdev implementation
 *****************************************************************************/

static void
nv50_instmem_fini(struct nvkm_instmem *base)
{
        nv50_instmem(base)->addr = ~0ULL;
}

static const struct nvkm_instmem_func
nv50_instmem = {
        .fini = nv50_instmem_fini,
        .memory_new = nv50_instobj_new,
        .zero = false,
};

int
nv50_instmem_new(struct nvkm_device *device, int index,
                 struct nvkm_instmem **pimem)
{
        struct nv50_instmem *imem;

        if (!(imem = kzalloc(sizeof(*imem), GFP_KERNEL)))
                return -ENOMEM;
        nvkm_instmem_ctor(&nv50_instmem, device, index, &imem->base);
        INIT_LIST_HEAD(&imem->lru);
        *pimem = &imem->base;
        return 0;
}