// SPDX-License-Identifier: GPL-2.0

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

#include <uapi/misc/habanalabs.h>
#include "habanalabs.h"

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

static void cb_fini(struct hl_device *hdev, struct hl_cb *cb)
{
        hdev->asic_funcs->asic_dma_free_coherent(hdev, cb->size,
                        (void *) (uintptr_t) cb->kernel_address,
                        cb->bus_address);
        kfree(cb);
}

static void cb_do_release(struct hl_device *hdev, struct hl_cb *cb)
{
        if (cb->is_pool) {
                spin_lock(&hdev->cb_pool_lock);
                list_add(&cb->pool_list, &hdev->cb_pool);
                spin_unlock(&hdev->cb_pool_lock);
        } else {
                cb_fini(hdev, cb);
        }
}

static void cb_release(struct kref *ref)
{
        struct hl_device *hdev;
        struct hl_cb *cb;

        cb = container_of(ref, struct hl_cb, refcount);
        hdev = cb->hdev;

        hl_debugfs_remove_cb(cb);

        cb_do_release(hdev, cb);
}

static struct hl_cb *hl_cb_alloc(struct hl_device *hdev, u32 cb_size,
                                        int ctx_id)
{
        struct hl_cb *cb;
        void *p;

        /*
         * We use of GFP_ATOMIC here because this function can be called from
         * the latency-sensitive code path for command submission. Due to H/W
         * limitations in some of the ASICs, the kernel must copy the user CB
         * that is designated for an external queue and actually enqueue
         * the kernel's copy. Hence, we must never sleep in this code section
         * and must use GFP_ATOMIC for all memory allocations.
         */
        if (ctx_id == HL_KERNEL_ASID_ID)
                cb = kzalloc(sizeof(*cb), GFP_ATOMIC);
        else
                cb = kzalloc(sizeof(*cb), GFP_KERNEL);

        if (!cb)
                return NULL;

        if (ctx_id == HL_KERNEL_ASID_ID)
                p = hdev->asic_funcs->asic_dma_alloc_coherent(hdev, cb_size,
                                                &cb->bus_address, GFP_ATOMIC);
        else
                p = hdev->asic_funcs->asic_dma_alloc_coherent(hdev, cb_size,
                                                &cb->bus_address,
                                                GFP_USER | __GFP_ZERO);
        if (!p) {
                dev_err(hdev->dev,
                        "failed to allocate %d of dma memory for CB\n",
                        cb_size);
                kfree(cb);
                return NULL;
        }

        cb->kernel_address = (u64) (uintptr_t) p;
        cb->size = cb_size;

        return cb;
}

int hl_cb_create(struct hl_device *hdev, struct hl_cb_mgr *mgr,
                        u32 cb_size, u64 *handle, int ctx_id)
{
        struct hl_cb *cb;
        bool alloc_new_cb = true;
        int rc;

        /*
         * Can't use generic function to check this because of special case
         * where we create a CB as part of the reset process
         */
        if ((hdev->disabled) || ((atomic_read(&hdev->in_reset)) &&
                                        (ctx_id != HL_KERNEL_ASID_ID))) {
                dev_warn_ratelimited(hdev->dev,
                        "Device is disabled or in reset. Can't create new CBs\n");
                rc = -EBUSY;
                goto out_err;
        }

        if (cb_size > HL_MAX_CB_SIZE) {
                dev_err(hdev->dev,
                        "CB size %d must be less then %d\n",
                        cb_size, HL_MAX_CB_SIZE);
                rc = -EINVAL;
                goto out_err;
        }

        /* Minimum allocation must be PAGE SIZE */
        if (cb_size < PAGE_SIZE)
                cb_size = PAGE_SIZE;

        if (ctx_id == HL_KERNEL_ASID_ID &&
                        cb_size <= hdev->asic_prop.cb_pool_cb_size) {

                spin_lock(&hdev->cb_pool_lock);
                if (!list_empty(&hdev->cb_pool)) {
                        cb = list_first_entry(&hdev->cb_pool, typeof(*cb),
                                        pool_list);
                        list_del(&cb->pool_list);
                        spin_unlock(&hdev->cb_pool_lock);
                        alloc_new_cb = false;
                } else {
                        spin_unlock(&hdev->cb_pool_lock);
                        dev_dbg(hdev->dev, "CB pool is empty\n");
                }
        }

        if (alloc_new_cb) {
                cb = hl_cb_alloc(hdev, cb_size, ctx_id);
                if (!cb) {
                        rc = -ENOMEM;
                        goto out_err;
                }
        }

        cb->hdev = hdev;
        cb->ctx_id = ctx_id;

        spin_lock(&mgr->cb_lock);
        rc = idr_alloc(&mgr->cb_handles, cb, 1, 0, GFP_ATOMIC);
        spin_unlock(&mgr->cb_lock);

        if (rc < 0) {
                dev_err(hdev->dev, "Failed to allocate IDR for a new CB\n");
                goto release_cb;
        }

        cb->id = rc;

        kref_init(&cb->refcount);
        spin_lock_init(&cb->lock);

        /*
         * idr is 32-bit so we can safely OR it with a mask that is above
         * 32 bit
         */
        *handle = cb->id | HL_MMAP_CB_MASK;
        *handle <<= PAGE_SHIFT;

        hl_debugfs_add_cb(cb);

        return 0;

release_cb:
        cb_do_release(hdev, cb);
out_err:
        *handle = 0;

        return rc;
}

int hl_cb_destroy(struct hl_device *hdev, struct hl_cb_mgr *mgr, u64 cb_handle)
{
        struct hl_cb *cb;
        u32 handle;
        int rc = 0;

        /*
         * handle was given to user to do mmap, I need to shift it back to
         * how the idr module gave it to me
         */
        cb_handle >>= PAGE_SHIFT;
        handle = (u32) cb_handle;

        spin_lock(&mgr->cb_lock);

        cb = idr_find(&mgr->cb_handles, handle);
        if (cb) {
                idr_remove(&mgr->cb_handles, handle);
                spin_unlock(&mgr->cb_lock);
                kref_put(&cb->refcount, cb_release);
        } else {
                spin_unlock(&mgr->cb_lock);
                dev_err(hdev->dev,
                        "CB destroy failed, no match to handle 0x%x\n", handle);
                rc = -EINVAL;
        }

        return rc;
}

int hl_cb_ioctl(struct hl_fpriv *hpriv, void *data)
{
        union hl_cb_args *args = data;
        struct hl_device *hdev = hpriv->hdev;
        u64 handle;
        int rc;

        if (hl_device_disabled_or_in_reset(hdev)) {
                dev_warn_ratelimited(hdev->dev,
                        "Device is %s. Can't execute CB IOCTL\n",
                        atomic_read(&hdev->in_reset) ? "in_reset" : "disabled");
                return -EBUSY;
        }

        switch (args->in.op) {
        case HL_CB_OP_CREATE:
                rc = hl_cb_create(hdev, &hpriv->cb_mgr, args->in.cb_size,
                                        &handle, hpriv->ctx->asid);
                memset(args, 0, sizeof(*args));
                args->out.cb_handle = handle;
                break;
        case HL_CB_OP_DESTROY:
                rc = hl_cb_destroy(hdev, &hpriv->cb_mgr,
                                        args->in.cb_handle);
                break;
        default:
                rc = -ENOTTY;
                break;
        }

        return rc;
}

static void cb_vm_close(struct vm_area_struct *vma)
{
        struct hl_cb *cb = (struct hl_cb *) vma->vm_private_data;
        long new_mmap_size;

        new_mmap_size = cb->mmap_size - (vma->vm_end - vma->vm_start);

        if (new_mmap_size > 0) {
                cb->mmap_size = new_mmap_size;
                return;
        }

        spin_lock(&cb->lock);
        cb->mmap = false;
        spin_unlock(&cb->lock);

        hl_cb_put(cb);
        vma->vm_private_data = NULL;
}

static const struct vm_operations_struct cb_vm_ops = {
        .close = cb_vm_close
};

int hl_cb_mmap(struct hl_fpriv *hpriv, struct vm_area_struct *vma)
{
        struct hl_device *hdev = hpriv->hdev;
        struct hl_cb *cb;
        phys_addr_t address;
        u32 handle;
        int rc;

        handle = vma->vm_pgoff;

        /* reference was taken here */
        cb = hl_cb_get(hdev, &hpriv->cb_mgr, handle);
        if (!cb) {
                dev_err(hdev->dev,
                        "CB mmap failed, no match to handle %d\n", handle);
                return -EINVAL;
        }

        /* Validation check */
        if ((vma->vm_end - vma->vm_start) != ALIGN(cb->size, PAGE_SIZE)) {
                dev_err(hdev->dev,
                        "CB mmap failed, mmap size 0x%lx != 0x%x cb size\n",
                        vma->vm_end - vma->vm_start, cb->size);
                rc = -EINVAL;
                goto put_cb;
        }

        spin_lock(&cb->lock);

        if (cb->mmap) {
                dev_err(hdev->dev,
                        "CB mmap failed, CB already mmaped to user\n");
                rc = -EINVAL;
                goto release_lock;
        }

        cb->mmap = true;

        spin_unlock(&cb->lock);

        vma->vm_ops = &cb_vm_ops;

        /*
         * Note: We're transferring the cb reference to
         * vma->vm_private_data here.
         */

        vma->vm_private_data = cb;

        /* Calculate address for CB */
        address = virt_to_phys((void *) (uintptr_t) cb->kernel_address);

        rc = hdev->asic_funcs->cb_mmap(hdev, vma, cb->kernel_address,
                                        address, cb->size);

        if (rc) {
                spin_lock(&cb->lock);
                cb->mmap = false;
                goto release_lock;
        }

        cb->mmap_size = cb->size;

        return 0;

release_lock:
        spin_unlock(&cb->lock);
put_cb:
        hl_cb_put(cb);
        return rc;
}

struct hl_cb *hl_cb_get(struct hl_device *hdev, struct hl_cb_mgr *mgr,
                        u32 handle)
{
        struct hl_cb *cb;

        spin_lock(&mgr->cb_lock);
        cb = idr_find(&mgr->cb_handles, handle);

        if (!cb) {
                spin_unlock(&mgr->cb_lock);
                dev_warn(hdev->dev,
                        "CB get failed, no match to handle %d\n", handle);
                return NULL;
        }

        kref_get(&cb->refcount);

        spin_unlock(&mgr->cb_lock);

        return cb;

}

void hl_cb_put(struct hl_cb *cb)
{
        kref_put(&cb->refcount, cb_release);
}

void hl_cb_mgr_init(struct hl_cb_mgr *mgr)
{
        spin_lock_init(&mgr->cb_lock);
        idr_init(&mgr->cb_handles);
}

void hl_cb_mgr_fini(struct hl_device *hdev, struct hl_cb_mgr *mgr)
{
        struct hl_cb *cb;
        struct idr *idp;
        u32 id;

        idp = &mgr->cb_handles;

        idr_for_each_entry(idp, cb, id) {
                if (kref_put(&cb->refcount, cb_release) != 1)
                        dev_err(hdev->dev,
                                "CB %d for CTX ID %d is still alive\n",
                                id, cb->ctx_id);
        }

        idr_destroy(&mgr->cb_handles);
}

struct hl_cb *hl_cb_kernel_create(struct hl_device *hdev, u32 cb_size)
{
        u64 cb_handle;
        struct hl_cb *cb;
        int rc;

        rc = hl_cb_create(hdev, &hdev->kernel_cb_mgr, cb_size, &cb_handle,
                        HL_KERNEL_ASID_ID);
        if (rc) {
                dev_err(hdev->dev,
                        "Failed to allocate CB for the kernel driver %d\n", rc);
                return NULL;
        }

        cb_handle >>= PAGE_SHIFT;
        cb = hl_cb_get(hdev, &hdev->kernel_cb_mgr, (u32) cb_handle);
        /* hl_cb_get should never fail here so use kernel WARN */
        WARN(!cb, "Kernel CB handle invalid 0x%x\n", (u32) cb_handle);
        if (!cb)
                goto destroy_cb;

        return cb;

destroy_cb:
        hl_cb_destroy(hdev, &hdev->kernel_cb_mgr, cb_handle << PAGE_SHIFT);

        return NULL;
}

int hl_cb_pool_init(struct hl_device *hdev)
{
        struct hl_cb *cb;
        int i;

        INIT_LIST_HEAD(&hdev->cb_pool);
        spin_lock_init(&hdev->cb_pool_lock);

        for (i = 0 ; i < hdev->asic_prop.cb_pool_cb_cnt ; i++) {
                cb = hl_cb_alloc(hdev, hdev->asic_prop.cb_pool_cb_size,
                                HL_KERNEL_ASID_ID);
                if (cb) {
                        cb->is_pool = true;
                        list_add(&cb->pool_list, &hdev->cb_pool);
                } else {
                        hl_cb_pool_fini(hdev);
                        return -ENOMEM;
                }
        }

        return 0;
}

int hl_cb_pool_fini(struct hl_device *hdev)
{
        struct hl_cb *cb, *tmp;

        list_for_each_entry_safe(cb, tmp, &hdev->cb_pool, pool_list) {
                list_del(&cb->pool_list);
                cb_fini(hdev, cb);
        }

        return 0;
}