/* QLogic qed NIC Driver
 * Copyright (c) 2015-2017  QLogic Corporation
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and /or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#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/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 unrequired */
        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/consme */
        u16 prod_idx;
        u16 cons_idx;
};

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

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 addresses of the chain pages,
                 * respectively to the physical addresses in the pbl table.
                 */
                void **pp_virt_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;

        u8 cnt_type;

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

        /* Base address of a pre-allocated buffer for pbl */
        struct {
                dma_addr_t p_phys_table;
                void *p_virt_table;
        } pbl_sp;

        /* Address of first page of the chain - the address is required
         * for fastpath operation [consume/produce] but only for the 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;

        u8 intended_use;
};

#define QED_CHAIN_PBL_ENTRY_SIZE        (8)
#define QED_CHAIN_PAGE_SIZE             (0x1000)
#define ELEMS_PER_PAGE(elem_size)       (QED_CHAIN_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, mode) \
        ((u32)(ELEMS_PER_PAGE(elem_size) -     \
               UNUSABLE_ELEMS_PER_PAGE(elem_size, mode)))

#define QED_CHAIN_PAGE_CNT(elem_cnt, elem_size, mode) \
        DIV_ROUND_UP(elem_cnt, USABLE_ELEMS_PER_PAGE(elem_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(struct qed_chain *p_chain)
{
        return p_chain->u.chain16.prod_idx;
}

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

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

static inline u16 qed_chain_get_elem_left(struct qed_chain *p_chain)
{
        u16 used;

        used = (u16) (((u32)0x10000 +
                       (u32)p_chain->u.chain16.prod_idx) -
                      (u32)p_chain->u.chain16.cons_idx);
        if (p_chain->mode == QED_CHAIN_MODE_NEXT_PTR)
                used -= p_chain->u.chain16.prod_idx / p_chain->elem_per_page -
                    p_chain->u.chain16.cons_idx / p_chain->elem_per_page;

        return (u16)(p_chain->capacity - used);
}

static inline u32 qed_chain_get_elem_left_u32(struct qed_chain *p_chain)
{
        u32 used;

        used = (u32) (((u64)0x100000000ULL +
                       (u64)p_chain->u.chain32.prod_idx) -
                      (u64)p_chain->u.chain32.cons_idx);
        if (p_chain->mode == QED_CHAIN_MODE_NEXT_PTR)
                used -= p_chain->u.chain32.prod_idx / p_chain->elem_per_page -
                    p_chain->u.chain32.cons_idx / p_chain->elem_per_page;

        return p_chain->capacity - used;
}

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

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

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

static inline dma_addr_t qed_chain_get_pbl_phys(struct qed_chain *p_chain)
{
        return p_chain->pbl_sp.p_phys_table;
}

/**
 * @brief qed_chain_advance_page -
 *
 * Advance the next element accros pages for a linked chain
 *
 * @param p_chain
 * @param p_next_elem
 * @param idx_to_inc
 * @param page_to_inc
 */
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_virt_addr_tbl[page_index];
        }
}

#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)

/**
 * @brief qed_chain_return_produced -
 *
 * A chain in which the driver "Produces" elements should use this API
 * to indicate previous produced elements are now consumed.
 *
 * @param p_chain
 */
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);
}

/**
 * @brief 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.
 *
 * @param p_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;
}

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

/**
 * @brief qed_chain_recycle_consumed -
 *
 * Returns an element which was previously consumed;
 * Increments producers so they could be written to FW.
 *
 * @param p_chain
 */
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++;
}

/**
 * @brief 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.
 *
 * @param p_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;
}

/**
 * @brief qed_chain_reset - Resets the chain to its start state
 *
 * @param p_chain pointer to a previously allocted chain
 */
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;
        }
}

/**
 * @brief qed_chain_init - Initalizes a basic chain struct
 *
 * @param p_chain
 * @param p_virt_addr
 * @param p_phys_addr   physical address of allocated buffer's beginning
 * @param page_cnt      number of pages in the allocated buffer
 * @param elem_size     size of each element in the chain
 * @param intended_use
 * @param mode
 */
static inline void qed_chain_init_params(struct qed_chain *p_chain,
                                         u32 page_cnt,
                                         u8 elem_size,
                                         enum qed_chain_use_mode intended_use,
                                         enum qed_chain_mode mode,
                                         enum qed_chain_cnt_type cnt_type)
{
        /* chain fixed parameters */
        p_chain->p_virt_addr = NULL;
        p_chain->p_phys_addr = 0;
        p_chain->elem_size      = elem_size;
        p_chain->intended_use = (u8)intended_use;
        p_chain->mode           = mode;
        p_chain->cnt_type = (u8)cnt_type;

        p_chain->elem_per_page = ELEMS_PER_PAGE(elem_size);
        p_chain->usable_per_page = USABLE_ELEMS_PER_PAGE(elem_size, mode);
        p_chain->elem_per_page_mask = p_chain->elem_per_page - 1;
        p_chain->elem_unusable = UNUSABLE_ELEMS_PER_PAGE(elem_size, mode);
        p_chain->next_page_mask = (p_chain->usable_per_page &
                                   p_chain->elem_per_page_mask);

        p_chain->page_cnt = page_cnt;
        p_chain->capacity = p_chain->usable_per_page * page_cnt;
        p_chain->size = p_chain->elem_per_page * page_cnt;

        p_chain->pbl_sp.p_phys_table = 0;
        p_chain->pbl_sp.p_virt_table = NULL;
        p_chain->pbl.pp_virt_addr_tbl = NULL;
}

/**
 * @brief qed_chain_init_mem -
 *
 * Initalizes a basic chain struct with its chain buffers
 *
 * @param p_chain
 * @param p_virt_addr   virtual address of allocated buffer's beginning
 * @param p_phys_addr   physical address of allocated buffer's beginning
 *
 */
static inline void qed_chain_init_mem(struct qed_chain *p_chain,
                                      void *p_virt_addr, dma_addr_t p_phys_addr)
{
        p_chain->p_virt_addr = p_virt_addr;
        p_chain->p_phys_addr = p_phys_addr;
}

/**
 * @brief qed_chain_init_pbl_mem -
 *
 * Initalizes a basic chain struct with its pbl buffers
 *
 * @param p_chain
 * @param p_virt_pbl    pointer to a pre allocated side table which will hold
 *                      virtual page addresses.
 * @param p_phys_pbl    pointer to a pre-allocated side table which will hold
 *                      physical page addresses.
 * @param pp_virt_addr_tbl
 *                      pointer to a pre-allocated side table which will hold
 *                      the virtual addresses of the chain pages.
 *
 */
static inline void qed_chain_init_pbl_mem(struct qed_chain *p_chain,
                                          void *p_virt_pbl,
                                          dma_addr_t p_phys_pbl,
                                          void **pp_virt_addr_tbl)
{
        p_chain->pbl_sp.p_phys_table = p_phys_pbl;
        p_chain->pbl_sp.p_virt_table = p_virt_pbl;
        p_chain->pbl.pp_virt_addr_tbl = pp_virt_addr_tbl;
}

/**
 * @brief qed_chain_init_next_ptr_elem -
 *
 * Initalizes a next pointer element
 *
 * @param p_chain
 * @param p_virt_curr   virtual address of a chain page of which the next
 *                      pointer element is initialized
 * @param p_virt_next   virtual address of the next chain page
 * @param p_phys_next   physical address of the next chain page
 *
 */
static inline void
qed_chain_init_next_ptr_elem(struct qed_chain *p_chain,
                             void *p_virt_curr,
                             void *p_virt_next, dma_addr_t p_phys_next)
{
        struct qed_chain_next *p_next;
        u32 size;

        size = p_chain->elem_size * p_chain->usable_per_page;
        p_next = (struct qed_chain_next *)((u8 *)p_virt_curr + size);

        DMA_REGPAIR_LE(p_next->next_phys, p_phys_next);

        p_next->next_virt = p_virt_next;
}

/**
 * @brief qed_chain_get_last_elem -
 *
 * Returns a pointer to the last element of the chain
 *
 * @param p_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_virt_addr_tbl[last_page_idx];
                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;
}

/**
 * @brief qed_chain_set_prod - sets the prod to the given value
 *
 * @param prod_idx
 * @param p_prod_elem
 */
static inline void qed_chain_set_prod(struct qed_chain *p_chain,
                                      u32 prod_idx, void *p_prod_elem)
{
        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;
}

/**
 * @brief qed_chain_pbl_zero_mem - set chain memory to 0
 *
 * @param p_chain
 */
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_virt_addr_tbl[i], 0,
                       QED_CHAIN_PAGE_SIZE);
}

#endif