/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
/*
 * Copyright (c) 2024, Microsoft Corporation. All rights reserved.
 */

#ifndef _MANA_SHADOW_QUEUE_H_
#define _MANA_SHADOW_QUEUE_H_

struct shadow_wqe_header {
        u16 opcode;
        u16 error_code;
        u32 posted_wqe_size;
        u64 wr_id;
};

struct ud_rq_shadow_wqe {
        struct shadow_wqe_header header;
        u32 byte_len;
        u32 src_qpn;
};

struct ud_sq_shadow_wqe {
        struct shadow_wqe_header header;
};

struct shadow_queue {
        /* Unmasked producer index, Incremented on wqe posting */
        u64 prod_idx;
        /* Unmasked consumer index, Incremented on cq polling */
        u64 cons_idx;
        /* Unmasked index of next-to-complete (from HW) shadow WQE */
        u64 next_to_complete_idx;
        /* queue size in wqes */
        u32 length;
        /* distance between elements in bytes */
        u32 stride;
        /* ring buffer holding wqes */
        void *buffer;
};

static inline int create_shadow_queue(struct shadow_queue *queue, uint32_t length, uint32_t stride)
{
        queue->buffer = kvmalloc_array(length, stride, GFP_KERNEL);
        if (!queue->buffer)
                return -ENOMEM;

        queue->length = length;
        queue->stride = stride;

        return 0;
}

static inline void destroy_shadow_queue(struct shadow_queue *queue)
{
        kvfree(queue->buffer);
}

static inline bool shadow_queue_full(struct shadow_queue *queue)
{
        return (queue->prod_idx - queue->cons_idx) >= queue->length;
}

static inline bool shadow_queue_empty(struct shadow_queue *queue)
{
        return queue->prod_idx == queue->cons_idx;
}

static inline void *
shadow_queue_get_element(const struct shadow_queue *queue, u64 unmasked_index)
{
        u32 index = unmasked_index % queue->length;

        return ((u8 *)queue->buffer + index * queue->stride);
}

static inline void *
shadow_queue_producer_entry(struct shadow_queue *queue)
{
        return shadow_queue_get_element(queue, queue->prod_idx);
}

static inline void *
shadow_queue_get_next_to_consume(const struct shadow_queue *queue)
{
        if (queue->cons_idx == queue->next_to_complete_idx)
                return NULL;

        return shadow_queue_get_element(queue, queue->cons_idx);
}

static inline void *
shadow_queue_get_next_to_complete(struct shadow_queue *queue)
{
        if (queue->next_to_complete_idx == queue->prod_idx)
                return NULL;

        return shadow_queue_get_element(queue, queue->next_to_complete_idx);
}

static inline void shadow_queue_advance_producer(struct shadow_queue *queue)
{
        queue->prod_idx++;
}

static inline void shadow_queue_advance_consumer(struct shadow_queue *queue)
{
        queue->cons_idx++;
}

static inline void shadow_queue_advance_next_to_complete(struct shadow_queue *queue)
{
        queue->next_to_complete_idx++;
}

#endif