// SPDX-License-Identifier: GPL-2.0

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

#include "habanalabs.h"

#include <linux/slab.h>

static void hl_ctx_fini(struct hl_ctx *ctx)
{
        struct hl_device *hdev = ctx->hdev;
        int i;

        /*
         * If we arrived here, there are no jobs waiting for this context
         * on its queues so we can safely remove it.
         * This is because for each CS, we increment the ref count and for
         * every CS that was finished we decrement it and we won't arrive
         * to this function unless the ref count is 0
         */

        for (i = 0 ; i < hdev->asic_prop.max_pending_cs ; i++)
                dma_fence_put(ctx->cs_pending[i]);

        kfree(ctx->cs_pending);

        if (ctx->asid != HL_KERNEL_ASID_ID) {
                /* The engines are stopped as there is no executing CS, but the
                 * Coresight might be still working by accessing addresses
                 * related to the stopped engines. Hence stop it explicitly.
                 * Stop only if this is the compute context, as there can be
                 * only one compute context
                 */
                if ((hdev->in_debug) && (hdev->compute_ctx == ctx))
                        hl_device_set_debug_mode(hdev, false);

                hl_vm_ctx_fini(ctx);
                hl_asid_free(hdev, ctx->asid);
        } else {
                hl_mmu_ctx_fini(ctx);
        }
}

void hl_ctx_do_release(struct kref *ref)
{
        struct hl_ctx *ctx;

        ctx = container_of(ref, struct hl_ctx, refcount);

        hl_ctx_fini(ctx);

        if (ctx->hpriv)
                hl_hpriv_put(ctx->hpriv);

        kfree(ctx);
}

int hl_ctx_create(struct hl_device *hdev, struct hl_fpriv *hpriv)
{
        struct hl_ctx_mgr *mgr = &hpriv->ctx_mgr;
        struct hl_ctx *ctx;
        int rc;

        ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
        if (!ctx) {
                rc = -ENOMEM;
                goto out_err;
        }

        mutex_lock(&mgr->ctx_lock);
        rc = idr_alloc(&mgr->ctx_handles, ctx, 1, 0, GFP_KERNEL);
        mutex_unlock(&mgr->ctx_lock);

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

        ctx->handle = rc;

        rc = hl_ctx_init(hdev, ctx, false);
        if (rc)
                goto remove_from_idr;

        hl_hpriv_get(hpriv);
        ctx->hpriv = hpriv;

        /* TODO: remove for multiple contexts per process */
        hpriv->ctx = ctx;

        /* TODO: remove the following line for multiple process support */
        hdev->compute_ctx = ctx;

        return 0;

remove_from_idr:
        mutex_lock(&mgr->ctx_lock);
        idr_remove(&mgr->ctx_handles, ctx->handle);
        mutex_unlock(&mgr->ctx_lock);
free_ctx:
        kfree(ctx);
out_err:
        return rc;
}

void hl_ctx_free(struct hl_device *hdev, struct hl_ctx *ctx)
{
        if (kref_put(&ctx->refcount, hl_ctx_do_release) == 1)
                return;

        dev_warn(hdev->dev,
                "user process released device but its command submissions are still executing\n");
}

int hl_ctx_init(struct hl_device *hdev, struct hl_ctx *ctx, bool is_kernel_ctx)
{
        int rc = 0;

        ctx->hdev = hdev;

        kref_init(&ctx->refcount);

        ctx->cs_sequence = 1;
        spin_lock_init(&ctx->cs_lock);
        atomic_set(&ctx->thread_ctx_switch_token, 1);
        ctx->thread_ctx_switch_wait_token = 0;
        ctx->cs_pending = kcalloc(hdev->asic_prop.max_pending_cs,
                                sizeof(struct dma_fence *),
                                GFP_KERNEL);
        if (!ctx->cs_pending)
                return -ENOMEM;

        if (is_kernel_ctx) {
                ctx->asid = HL_KERNEL_ASID_ID; /* Kernel driver gets ASID 0 */
                rc = hl_mmu_ctx_init(ctx);
                if (rc) {
                        dev_err(hdev->dev, "Failed to init mmu ctx module\n");
                        goto err_free_cs_pending;
                }
        } else {
                ctx->asid = hl_asid_alloc(hdev);
                if (!ctx->asid) {
                        dev_err(hdev->dev, "No free ASID, failed to create context\n");
                        rc = -ENOMEM;
                        goto err_free_cs_pending;
                }

                rc = hl_vm_ctx_init(ctx);
                if (rc) {
                        dev_err(hdev->dev, "Failed to init mem ctx module\n");
                        rc = -ENOMEM;
                        goto err_asid_free;
                }

                rc = hdev->asic_funcs->ctx_init(ctx);
                if (rc) {
                        dev_err(hdev->dev, "ctx_init failed\n");
                        goto err_vm_ctx_fini;
                }
        }

        return 0;

err_vm_ctx_fini:
        hl_vm_ctx_fini(ctx);
err_asid_free:
        hl_asid_free(hdev, ctx->asid);
err_free_cs_pending:
        kfree(ctx->cs_pending);

        return rc;
}

void hl_ctx_get(struct hl_device *hdev, struct hl_ctx *ctx)
{
        kref_get(&ctx->refcount);
}

int hl_ctx_put(struct hl_ctx *ctx)
{
        return kref_put(&ctx->refcount, hl_ctx_do_release);
}

struct dma_fence *hl_ctx_get_fence(struct hl_ctx *ctx, u64 seq)
{
        struct asic_fixed_properties *asic_prop = &ctx->hdev->asic_prop;
        struct dma_fence *fence;

        spin_lock(&ctx->cs_lock);

        if (seq >= ctx->cs_sequence) {
                spin_unlock(&ctx->cs_lock);
                return ERR_PTR(-EINVAL);
        }

        if (seq + asic_prop->max_pending_cs < ctx->cs_sequence) {
                spin_unlock(&ctx->cs_lock);
                return NULL;
        }

        fence = dma_fence_get(
                        ctx->cs_pending[seq & (asic_prop->max_pending_cs - 1)]);
        spin_unlock(&ctx->cs_lock);

        return fence;
}

/*
 * hl_ctx_mgr_init - initialize the context manager
 *
 * @mgr: pointer to context manager structure
 *
 * This manager is an object inside the hpriv object of the user process.
 * The function is called when a user process opens the FD.
 */
void hl_ctx_mgr_init(struct hl_ctx_mgr *mgr)
{
        mutex_init(&mgr->ctx_lock);
        idr_init(&mgr->ctx_handles);
}

/*
 * hl_ctx_mgr_fini - finalize the context manager
 *
 * @hdev: pointer to device structure
 * @mgr: pointer to context manager structure
 *
 * This function goes over all the contexts in the manager and frees them.
 * It is called when a process closes the FD.
 */
void hl_ctx_mgr_fini(struct hl_device *hdev, struct hl_ctx_mgr *mgr)
{
        struct hl_ctx *ctx;
        struct idr *idp;
        u32 id;

        idp = &mgr->ctx_handles;

        idr_for_each_entry(idp, ctx, id)
                hl_ctx_free(hdev, ctx);

        idr_destroy(&mgr->ctx_handles);
        mutex_destroy(&mgr->ctx_lock);
}