/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
/*
 * Copyright(c) 2016 Intel Corporation.
 */

#ifndef DEF_RDMAVT_INCMR_H
#define DEF_RDMAVT_INCMR_H

/*
 * For Memory Regions. This stuff should probably be moved into rdmavt/mr.h once
 * drivers no longer need access to the MR directly.
 */
#include <linux/percpu-refcount.h>

/*
 * A segment is a linear region of low physical memory.
 * Used by the verbs layer.
 */
struct rvt_seg {
        void *vaddr;
        size_t length;
};

/* The number of rvt_segs that fit in a page. */
#define RVT_SEGSZ     (PAGE_SIZE / sizeof(struct rvt_seg))

struct rvt_segarray {
        struct rvt_seg segs[RVT_SEGSZ];
};

struct rvt_mregion {
        struct ib_pd *pd;       /* shares refcnt of ibmr.pd */
        u64 user_base;          /* User's address for this region */
        u64 iova;               /* IB start address of this region */
        size_t length;
        u32 lkey;
        u32 offset;             /* offset (bytes) to start of region */
        int access_flags;
        u32 max_segs;           /* number of rvt_segs in all the arrays */
        u32 mapsz;              /* size of the map array */
        atomic_t lkey_invalid;  /* true if current lkey is invalid */
        u8  page_shift;         /* 0 - non unform/non powerof2 sizes */
        u8  lkey_published;     /* in global table */
        struct percpu_ref refcount;
        struct completion comp; /* complete when refcount goes to zero */
        struct rvt_segarray *map[];    /* the segments */
};

#define RVT_MAX_LKEY_TABLE_BITS 23

struct rvt_lkey_table {
        /* read mostly fields */
        u32 max;                /* size of the table */
        u32 shift;              /* lkey/rkey shift */
        struct rvt_mregion __rcu **table;
        /* writeable fields */
        /* protect changes in this struct */
        spinlock_t lock ____cacheline_aligned_in_smp;
        u32 next;               /* next unused index (speeds search) */
        u32 gen;                /* generation count */
};

/*
 * These keep track of the copy progress within a memory region.
 * Used by the verbs layer.
 */
struct rvt_sge {
        struct rvt_mregion *mr;
        void *vaddr;            /* kernel virtual address of segment */
        u32 sge_length;         /* length of the SGE */
        u32 length;             /* remaining length of the segment */
        u16 m;                  /* current index: mr->map[m] */
        u16 n;                  /* current index: mr->map[m]->segs[n] */
};

struct rvt_sge_state {
        struct rvt_sge *sg_list;      /* next SGE to be used if any */
        struct rvt_sge sge;   /* progress state for the current SGE */
        u32 total_len;
        u8 num_sge;
};

static inline void rvt_put_mr(struct rvt_mregion *mr)
{
        percpu_ref_put(&mr->refcount);
}

static inline void rvt_get_mr(struct rvt_mregion *mr)
{
        percpu_ref_get(&mr->refcount);
}

static inline void rvt_put_ss(struct rvt_sge_state *ss)
{
        while (ss->num_sge) {
                rvt_put_mr(ss->sge.mr);
                if (--ss->num_sge)
                        ss->sge = *ss->sg_list++;
        }
}

static inline u32 rvt_get_sge_length(struct rvt_sge *sge, u32 length)
{
        u32 len = sge->length;

        if (len > length)
                len = length;
        if (len > sge->sge_length)
                len = sge->sge_length;

        return len;
}

static inline void rvt_update_sge(struct rvt_sge_state *ss, u32 length,
                                  bool release)
{
        struct rvt_sge *sge = &ss->sge;

        sge->vaddr += length;
        sge->length -= length;
        sge->sge_length -= length;
        if (sge->sge_length == 0) {
                if (release)
                        rvt_put_mr(sge->mr);
                if (--ss->num_sge)
                        *sge = *ss->sg_list++;
        } else if (sge->length == 0 && sge->mr->lkey) {
                if (++sge->n >= RVT_SEGSZ) {
                        if (++sge->m >= sge->mr->mapsz)
                                return;
                        sge->n = 0;
                }
                sge->vaddr = sge->mr->map[sge->m]->segs[sge->n].vaddr;
                sge->length = sge->mr->map[sge->m]->segs[sge->n].length;
        }
}

static inline void rvt_skip_sge(struct rvt_sge_state *ss, u32 length,
                                bool release)
{
        struct rvt_sge *sge = &ss->sge;

        while (length) {
                u32 len = rvt_get_sge_length(sge, length);

                WARN_ON_ONCE(len == 0);
                rvt_update_sge(ss, len, release);
                length -= len;
        }
}

bool rvt_ss_has_lkey(struct rvt_sge_state *ss, u32 lkey);
bool rvt_mr_has_lkey(struct rvt_mregion *mr, u32 lkey);

#endif          /* DEF_RDMAVT_INCMRH */