/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */
/* QLogic qed NIC Driver
 * Copyright (c) 2015-2017  QLogic Corporation
 * Copyright (c) 2019-2020 Marvell International Ltd.
 */

#ifndef _QED_CHAIN_H
#define _QED_CHAIN_H

#include <linux/types.h>
#include <asm/byteorder.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/qed/common_hsi.h>

enum qed_chain_mode {
        /* Each Page contains a next pointer at its end */
        QED_CHAIN_MODE_NEXT_PTR,

        /* Chain is a single page (next ptr) is not required */
        QED_CHAIN_MODE_SINGLE,

        /* Page pointers are located in a side list */
        QED_CHAIN_MODE_PBL,
};

enum qed_chain_use_mode {
        QED_CHAIN_USE_TO_PRODUCE,                       /* Chain starts empty */
        QED_CHAIN_USE_TO_CONSUME,                       /* Chain starts full */
        QED_CHAIN_USE_TO_CONSUME_PRODUCE,               /* Chain starts empty */
};

enum qed_chain_cnt_type {
        /* The chain's size/prod/cons are kept in 16-bit variables */
        QED_CHAIN_CNT_TYPE_U16,

        /* The chain's size/prod/cons are kept in 32-bit variables  */
        QED_CHAIN_CNT_TYPE_U32,
};

struct qed_chain_next {
        struct regpair                                  next_phys;
        void                                            *next_virt;
};

struct qed_chain_pbl_u16 {
        u16                                             prod_page_idx;
        u16                                             cons_page_idx;
};

struct qed_chain_pbl_u32 {
        u32                                             prod_page_idx;
        u32                                             cons_page_idx;
};

struct qed_chain_u16 {
        /* Cyclic index of next element to produce/consume */
        u16                                             prod_idx;
        u16                                             cons_idx;
};

struct qed_chain_u32 {
        /* Cyclic index of next element to produce/consume */
        u32                                             prod_idx;
        u32                                             cons_idx;
};

struct addr_tbl_entry {
        void                                            *virt_addr;
        dma_addr_t                                      dma_map;
};

struct qed_chain {
        /* Fastpath portion of the chain - required for commands such
         * as produce / consume.
         */

        /* Point to next element to produce/consume */
        void                                            *p_prod_elem;
        void                                            *p_cons_elem;

        /* Fastpath portions of the PBL [if exists] */

        struct {
                /* Table for keeping the virtual and physical addresses of the
                 * chain pages, respectively to the physical addresses
                 * in the pbl table.
                 */
                struct addr_tbl_entry                   *pp_addr_tbl;

                union {
                        struct qed_chain_pbl_u16        u16;
                        struct qed_chain_pbl_u32        u32;
                }                                       c;
        }                                               pbl;

        union {
                struct qed_chain_u16                    chain16;
                struct qed_chain_u32                    chain32;
        }                                               u;

        /* Capacity counts only usable elements */
        u32                                             capacity;
        u32                                             page_cnt;

        enum qed_chain_mode                             mode;

        /* Elements information for fast calculations */
        u16                                             elem_per_page;
        u16                                             elem_per_page_mask;
        u16                                             elem_size;
        u16                                             next_page_mask;
        u16                                             usable_per_page;
        u8                                              elem_unusable;

        enum qed_chain_cnt_type                         cnt_type;

        /* Slowpath of the chain - required for initialization and destruction,
         * but isn't involved in regular functionality.
         */

        u32                                             page_size;

        /* Base address of a pre-allocated buffer for pbl */
        struct {
                __le64                                  *table_virt;
                dma_addr_t                              table_phys;
                size_t                                  table_size;
        }                                               pbl_sp;

        /* Address of first page of the chain - the address is required
         * for fastpath operation [consume/produce] but only for the SINGLE
         * flavour which isn't considered fastpath [== SPQ].
         */
        void                                            *p_virt_addr;
        dma_addr_t                                      p_phys_addr;

        /* Total number of elements [for entire chain] */
        u32                                             size;

        enum qed_chain_use_mode                         intended_use;

        bool                                            b_external_pbl;
};

struct qed_chain_init_params {
        enum qed_chain_mode                             mode;
        enum qed_chain_use_mode                         intended_use;
        enum qed_chain_cnt_type                         cnt_type;

        u32                                             page_size;
        u32                                             num_elems;
        size_t                                          elem_size;

        void                                            *ext_pbl_virt;
        dma_addr_t                                      ext_pbl_phys;
};

#define QED_CHAIN_PAGE_SIZE                             SZ_4K

#define ELEMS_PER_PAGE(elem_size, page_size)                                 \
        ((page_size) / (elem_size))

#define UNUSABLE_ELEMS_PER_PAGE(elem_size, mode)                             \
        (((mode) == QED_CHAIN_MODE_NEXT_PTR) ?                               \
         (u8)(1 + ((sizeof(struct qed_chain_next) - 1) / (elem_size))) :     \
         0)

#define USABLE_ELEMS_PER_PAGE(elem_size, page_size, mode)                    \
        ((u32)(ELEMS_PER_PAGE((elem_size), (page_size)) -                    \
               UNUSABLE_ELEMS_PER_PAGE((elem_size), (mode))))

#define QED_CHAIN_PAGE_CNT(elem_cnt, elem_size, page_size, mode)             \
        DIV_ROUND_UP((elem_cnt),                                             \
                     USABLE_ELEMS_PER_PAGE((elem_size), (page_size), (mode)))

#define is_chain_u16(p)                                                      \
        ((p)->cnt_type == QED_CHAIN_CNT_TYPE_U16)
#define is_chain_u32(p)                                                      \
        ((p)->cnt_type == QED_CHAIN_CNT_TYPE_U32)

/* Accessors */

static inline u16 qed_chain_get_prod_idx(const struct qed_chain *chain)
{
        return chain->u.chain16.prod_idx;
}

static inline u16 qed_chain_get_cons_idx(const struct qed_chain *chain)
{
        return chain->u.chain16.cons_idx;
}

static inline u32 qed_chain_get_prod_idx_u32(const struct qed_chain *chain)
{
        return chain->u.chain32.prod_idx;
}

static inline u32 qed_chain_get_cons_idx_u32(const struct qed_chain *chain)
{
        return chain->u.chain32.cons_idx;
}

static inline u16 qed_chain_get_elem_used(const struct qed_chain *chain)
{
        u32 prod = qed_chain_get_prod_idx(chain);
        u32 cons = qed_chain_get_cons_idx(chain);
        u16 elem_per_page = chain->elem_per_page;
        u16 used;

        if (prod < cons)
                prod += (u32)U16_MAX + 1;

        used = (u16)(prod - cons);
        if (chain->mode == QED_CHAIN_MODE_NEXT_PTR)
                used -= (u16)(prod / elem_per_page - cons / elem_per_page);

        return used;
}

static inline u16 qed_chain_get_elem_left(const struct qed_chain *chain)
{
        return (u16)(chain->capacity - qed_chain_get_elem_used(chain));
}

static inline u32 qed_chain_get_elem_used_u32(const struct qed_chain *chain)
{
        u64 prod = qed_chain_get_prod_idx_u32(chain);
        u64 cons = qed_chain_get_cons_idx_u32(chain);
        u16 elem_per_page = chain->elem_per_page;
        u32 used;

        if (prod < cons)
                prod += (u64)U32_MAX + 1;

        used = (u32)(prod - cons);
        if (chain->mode == QED_CHAIN_MODE_NEXT_PTR)
                used -= (u32)(prod / elem_per_page - cons / elem_per_page);

        return used;
}

static inline u32 qed_chain_get_elem_left_u32(const struct qed_chain *chain)
{
        return chain->capacity - qed_chain_get_elem_used_u32(chain);
}

static inline u16 qed_chain_get_usable_per_page(const struct qed_chain *chain)
{
        return chain->usable_per_page;
}

static inline u8 qed_chain_get_unusable_per_page(const struct qed_chain *chain)
{
        return chain->elem_unusable;
}

static inline u32 qed_chain_get_page_cnt(const struct qed_chain *chain)
{
        return chain->page_cnt;
}

static inline dma_addr_t qed_chain_get_pbl_phys(const struct qed_chain *chain)
{
        return chain->pbl_sp.table_phys;
}

/**
 * qed_chain_advance_page(): Advance the next element across pages for a
 *                           linked chain.
 *
 * @p_chain: P_chain.
 * @p_next_elem: P_next_elem.
 * @idx_to_inc: Idx_to_inc.
 * @page_to_inc: page_to_inc.
 *
 * Return: Void.
 */
static inline void
qed_chain_advance_page(struct qed_chain *p_chain,
                       void **p_next_elem, void *idx_to_inc, void *page_to_inc)
{
        struct qed_chain_next *p_next = NULL;
        u32 page_index = 0;

        switch (p_chain->mode) {
        case QED_CHAIN_MODE_NEXT_PTR:
                p_next = *p_next_elem;
                *p_next_elem = p_next->next_virt;
                if (is_chain_u16(p_chain))
                        *(u16 *)idx_to_inc += p_chain->elem_unusable;
                else
                        *(u32 *)idx_to_inc += p_chain->elem_unusable;
                break;
        case QED_CHAIN_MODE_SINGLE:
                *p_next_elem = p_chain->p_virt_addr;
                break;

        case QED_CHAIN_MODE_PBL:
                if (is_chain_u16(p_chain)) {
                        if (++(*(u16 *)page_to_inc) == p_chain->page_cnt)
                                *(u16 *)page_to_inc = 0;
                        page_index = *(u16 *)page_to_inc;
                } else {
                        if (++(*(u32 *)page_to_inc) == p_chain->page_cnt)
                                *(u32 *)page_to_inc = 0;
                        page_index = *(u32 *)page_to_inc;
                }
                *p_next_elem = p_chain->pbl.pp_addr_tbl[page_index].virt_addr;
        }
}

#define is_unusable_idx(p, idx) \
        (((p)->u.chain16.idx & (p)->elem_per_page_mask) == (p)->usable_per_page)

#define is_unusable_idx_u32(p, idx) \
        (((p)->u.chain32.idx & (p)->elem_per_page_mask) == (p)->usable_per_page)
#define is_unusable_next_idx(p, idx)                             \
        ((((p)->u.chain16.idx + 1) & (p)->elem_per_page_mask) == \
         (p)->usable_per_page)

#define is_unusable_next_idx_u32(p, idx)                         \
        ((((p)->u.chain32.idx + 1) & (p)->elem_per_page_mask) == \
         (p)->usable_per_page)

#define test_and_skip(p, idx)                                              \
        do {                                            \
                if (is_chain_u16(p)) {                                     \
                        if (is_unusable_idx(p, idx))                       \
                                (p)->u.chain16.idx += (p)->elem_unusable;  \
                } else {                                                   \
                        if (is_unusable_idx_u32(p, idx))                   \
                                (p)->u.chain32.idx += (p)->elem_unusable;  \
                }                                       \
        } while (0)

/**
 * qed_chain_return_produced(): A chain in which the driver "Produces"
 *                              elements should use this API
 *                              to indicate previous produced elements
 *                              are now consumed.
 *
 * @p_chain: Chain.
 *
 * Return: Void.
 */
static inline void qed_chain_return_produced(struct qed_chain *p_chain)
{
        if (is_chain_u16(p_chain))
                p_chain->u.chain16.cons_idx++;
        else
                p_chain->u.chain32.cons_idx++;
        test_and_skip(p_chain, cons_idx);
}

/**
 * qed_chain_produce(): A chain in which the driver "Produces"
 *                      elements should use this to get a pointer to
 *                      the next element which can be "Produced". It's driver
 *                      responsibility to validate that the chain has room for
 *                      new element.
 *
 * @p_chain: Chain.
 *
 * Return: void*, a pointer to next element.
 */
static inline void *qed_chain_produce(struct qed_chain *p_chain)
{
        void *p_ret = NULL, *p_prod_idx, *p_prod_page_idx;

        if (is_chain_u16(p_chain)) {
                if ((p_chain->u.chain16.prod_idx &
                     p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
                        p_prod_idx = &p_chain->u.chain16.prod_idx;
                        p_prod_page_idx = &p_chain->pbl.c.u16.prod_page_idx;
                        qed_chain_advance_page(p_chain, &p_chain->p_prod_elem,
                                               p_prod_idx, p_prod_page_idx);
                }
                p_chain->u.chain16.prod_idx++;
        } else {
                if ((p_chain->u.chain32.prod_idx &
                     p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
                        p_prod_idx = &p_chain->u.chain32.prod_idx;
                        p_prod_page_idx = &p_chain->pbl.c.u32.prod_page_idx;
                        qed_chain_advance_page(p_chain, &p_chain->p_prod_elem,
                                               p_prod_idx, p_prod_page_idx);
                }
                p_chain->u.chain32.prod_idx++;
        }

        p_ret = p_chain->p_prod_elem;
        p_chain->p_prod_elem = (void *)(((u8 *)p_chain->p_prod_elem) +
                                        p_chain->elem_size);

        return p_ret;
}

/**
 * qed_chain_get_capacity(): Get the maximum number of BDs in chain
 *
 * @p_chain: Chain.
 *
 * Return: number of unusable BDs.
 */
static inline u32 qed_chain_get_capacity(struct qed_chain *p_chain)
{
        return p_chain->capacity;
}

/**
 * qed_chain_recycle_consumed(): Returns an element which was
 *                               previously consumed;
 *                               Increments producers so they could
 *                               be written to FW.
 *
 * @p_chain: Chain.
 *
 * Return: Void.
 */
static inline void qed_chain_recycle_consumed(struct qed_chain *p_chain)
{
        test_and_skip(p_chain, prod_idx);
        if (is_chain_u16(p_chain))
                p_chain->u.chain16.prod_idx++;
        else
                p_chain->u.chain32.prod_idx++;
}

/**
 * qed_chain_consume(): A Chain in which the driver utilizes data written
 *                      by a different source (i.e., FW) should use this to
 *                      access passed buffers.
 *
 * @p_chain: Chain.
 *
 * Return: void*, a pointer to the next buffer written.
 */
static inline void *qed_chain_consume(struct qed_chain *p_chain)
{
        void *p_ret = NULL, *p_cons_idx, *p_cons_page_idx;

        if (is_chain_u16(p_chain)) {
                if ((p_chain->u.chain16.cons_idx &
                     p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
                        p_cons_idx = &p_chain->u.chain16.cons_idx;
                        p_cons_page_idx = &p_chain->pbl.c.u16.cons_page_idx;
                        qed_chain_advance_page(p_chain, &p_chain->p_cons_elem,
                                               p_cons_idx, p_cons_page_idx);
                }
                p_chain->u.chain16.cons_idx++;
        } else {
                if ((p_chain->u.chain32.cons_idx &
                     p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
                        p_cons_idx = &p_chain->u.chain32.cons_idx;
                        p_cons_page_idx = &p_chain->pbl.c.u32.cons_page_idx;
                        qed_chain_advance_page(p_chain, &p_chain->p_cons_elem,
                                               p_cons_idx, p_cons_page_idx);
                }
                p_chain->u.chain32.cons_idx++;
        }

        p_ret = p_chain->p_cons_elem;
        p_chain->p_cons_elem = (void *)(((u8 *)p_chain->p_cons_elem) +
                                        p_chain->elem_size);

        return p_ret;
}

/**
 * qed_chain_reset(): Resets the chain to its start state.
 *
 * @p_chain: pointer to a previously allocated chain.
 *
 * Return Void.
 */
static inline void qed_chain_reset(struct qed_chain *p_chain)
{
        u32 i;

        if (is_chain_u16(p_chain)) {
                p_chain->u.chain16.prod_idx = 0;
                p_chain->u.chain16.cons_idx = 0;
        } else {
                p_chain->u.chain32.prod_idx = 0;
                p_chain->u.chain32.cons_idx = 0;
        }
        p_chain->p_cons_elem = p_chain->p_virt_addr;
        p_chain->p_prod_elem = p_chain->p_virt_addr;

        if (p_chain->mode == QED_CHAIN_MODE_PBL) {
                /* Use (page_cnt - 1) as a reset value for the prod/cons page's
                 * indices, to avoid unnecessary page advancing on the first
                 * call to qed_chain_produce/consume. Instead, the indices
                 * will be advanced to page_cnt and then will be wrapped to 0.
                 */
                u32 reset_val = p_chain->page_cnt - 1;

                if (is_chain_u16(p_chain)) {
                        p_chain->pbl.c.u16.prod_page_idx = (u16)reset_val;
                        p_chain->pbl.c.u16.cons_page_idx = (u16)reset_val;
                } else {
                        p_chain->pbl.c.u32.prod_page_idx = reset_val;
                        p_chain->pbl.c.u32.cons_page_idx = reset_val;
                }
        }

        switch (p_chain->intended_use) {
        case QED_CHAIN_USE_TO_CONSUME:
                /* produce empty elements */
                for (i = 0; i < p_chain->capacity; i++)
                        qed_chain_recycle_consumed(p_chain);
                break;

        case QED_CHAIN_USE_TO_CONSUME_PRODUCE:
        case QED_CHAIN_USE_TO_PRODUCE:
        default:
                /* Do nothing */
                break;
        }
}

/**
 * qed_chain_get_last_elem(): Returns a pointer to the last element of the
 *                            chain.
 *
 * @p_chain: Chain.
 *
 * Return: void*.
 */
static inline void *qed_chain_get_last_elem(struct qed_chain *p_chain)
{
        struct qed_chain_next *p_next = NULL;
        void *p_virt_addr = NULL;
        u32 size, last_page_idx;

        if (!p_chain->p_virt_addr)
                goto out;

        switch (p_chain->mode) {
        case QED_CHAIN_MODE_NEXT_PTR:
                size = p_chain->elem_size * p_chain->usable_per_page;
                p_virt_addr = p_chain->p_virt_addr;
                p_next = (struct qed_chain_next *)((u8 *)p_virt_addr + size);
                while (p_next->next_virt != p_chain->p_virt_addr) {
                        p_virt_addr = p_next->next_virt;
                        p_next = (struct qed_chain_next *)((u8 *)p_virt_addr +
                                                           size);
                }
                break;
        case QED_CHAIN_MODE_SINGLE:
                p_virt_addr = p_chain->p_virt_addr;
                break;
        case QED_CHAIN_MODE_PBL:
                last_page_idx = p_chain->page_cnt - 1;
                p_virt_addr = p_chain->pbl.pp_addr_tbl[last_page_idx].virt_addr;
                break;
        }
        /* p_virt_addr points at this stage to the last page of the chain */
        size = p_chain->elem_size * (p_chain->usable_per_page - 1);
        p_virt_addr = (u8 *)p_virt_addr + size;
out:
        return p_virt_addr;
}

/**
 * qed_chain_set_prod(): sets the prod to the given value.
 *
 * @p_chain: Chain.
 * @prod_idx: Prod Idx.
 * @p_prod_elem: Prod elem.
 *
 * Return Void.
 */
static inline void qed_chain_set_prod(struct qed_chain *p_chain,
                                      u32 prod_idx, void *p_prod_elem)
{
        if (p_chain->mode == QED_CHAIN_MODE_PBL) {
                u32 cur_prod, page_mask, page_cnt, page_diff;

                cur_prod = is_chain_u16(p_chain) ? p_chain->u.chain16.prod_idx :
                           p_chain->u.chain32.prod_idx;

                /* Assume that number of elements in a page is power of 2 */
                page_mask = ~p_chain->elem_per_page_mask;

                /* Use "cur_prod - 1" and "prod_idx - 1" since producer index
                 * reaches the first element of next page before the page index
                 * is incremented. See qed_chain_produce().
                 * Index wrap around is not a problem because the difference
                 * between current and given producer indices is always
                 * positive and lower than the chain's capacity.
                 */
                page_diff = (((cur_prod - 1) & page_mask) -
                             ((prod_idx - 1) & page_mask)) /
                            p_chain->elem_per_page;

                page_cnt = qed_chain_get_page_cnt(p_chain);
                if (is_chain_u16(p_chain))
                        p_chain->pbl.c.u16.prod_page_idx =
                                (p_chain->pbl.c.u16.prod_page_idx -
                                 page_diff + page_cnt) % page_cnt;
                else
                        p_chain->pbl.c.u32.prod_page_idx =
                                (p_chain->pbl.c.u32.prod_page_idx -
                                 page_diff + page_cnt) % page_cnt;
        }

        if (is_chain_u16(p_chain))
                p_chain->u.chain16.prod_idx = (u16) prod_idx;
        else
                p_chain->u.chain32.prod_idx = prod_idx;
        p_chain->p_prod_elem = p_prod_elem;
}

/**
 * qed_chain_pbl_zero_mem(): set chain memory to 0.
 *
 * @p_chain: Chain.
 *
 * Return: Void.
 */
static inline void qed_chain_pbl_zero_mem(struct qed_chain *p_chain)
{
        u32 i, page_cnt;

        if (p_chain->mode != QED_CHAIN_MODE_PBL)
                return;

        page_cnt = qed_chain_get_page_cnt(p_chain);

        for (i = 0; i < page_cnt; i++)
                memset(p_chain->pbl.pp_addr_tbl[i].virt_addr, 0,
                       p_chain->page_size);
}

#endif