// SPDX-License-Identifier: GPL-2.0
/* Marvell Octeon EP (EndPoint) Ethernet Driver
 *
 * Copyright (C) 2020 Marvell.
 *
 */
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mutex.h>
#include <linux/jiffies.h>
#include <linux/sched.h>
#include <linux/sched/signal.h>
#include <linux/io.h>
#include <linux/pci.h>
#include <linux/etherdevice.h>

#include "octep_ctrl_mbox.h"
#include "octep_config.h"
#include "octep_main.h"

/* Timeout in msecs for message response */
#define OCTEP_CTRL_MBOX_MSG_TIMEOUT_MS                  100
/* Time in msecs to wait for message response */
#define OCTEP_CTRL_MBOX_MSG_WAIT_MS                     10

/* Size of mbox info in bytes */
#define OCTEP_CTRL_MBOX_INFO_SZ                         256
/* Size of mbox host to fw queue info in bytes */
#define OCTEP_CTRL_MBOX_H2FQ_INFO_SZ                    16
/* Size of mbox fw to host queue info in bytes */
#define OCTEP_CTRL_MBOX_F2HQ_INFO_SZ                    16

#define OCTEP_CTRL_MBOX_TOTAL_INFO_SZ   (OCTEP_CTRL_MBOX_INFO_SZ + \
                                         OCTEP_CTRL_MBOX_H2FQ_INFO_SZ + \
                                         OCTEP_CTRL_MBOX_F2HQ_INFO_SZ)

#define OCTEP_CTRL_MBOX_INFO_MAGIC_NUM(m)       (m)
#define OCTEP_CTRL_MBOX_INFO_BARMEM_SZ(m)       ((m) + 8)
#define OCTEP_CTRL_MBOX_INFO_HOST_VERSION(m)   ((m) + 16)
#define OCTEP_CTRL_MBOX_INFO_HOST_STATUS(m)     ((m) + 24)
#define OCTEP_CTRL_MBOX_INFO_FW_VERSION(m)     ((m) + 136)
#define OCTEP_CTRL_MBOX_INFO_FW_STATUS(m)       ((m) + 144)

#define OCTEP_CTRL_MBOX_H2FQ_INFO(m)    ((m) + OCTEP_CTRL_MBOX_INFO_SZ)
#define OCTEP_CTRL_MBOX_H2FQ_PROD(m)    (OCTEP_CTRL_MBOX_H2FQ_INFO(m))
#define OCTEP_CTRL_MBOX_H2FQ_CONS(m)    ((OCTEP_CTRL_MBOX_H2FQ_INFO(m)) + 4)
#define OCTEP_CTRL_MBOX_H2FQ_SZ(m)      ((OCTEP_CTRL_MBOX_H2FQ_INFO(m)) + 8)

#define OCTEP_CTRL_MBOX_F2HQ_INFO(m)    ((m) + \
                                         OCTEP_CTRL_MBOX_INFO_SZ + \
                                         OCTEP_CTRL_MBOX_H2FQ_INFO_SZ)
#define OCTEP_CTRL_MBOX_F2HQ_PROD(m)    (OCTEP_CTRL_MBOX_F2HQ_INFO(m))
#define OCTEP_CTRL_MBOX_F2HQ_CONS(m)    ((OCTEP_CTRL_MBOX_F2HQ_INFO(m)) + 4)
#define OCTEP_CTRL_MBOX_F2HQ_SZ(m)      ((OCTEP_CTRL_MBOX_F2HQ_INFO(m)) + 8)

static const u32 mbox_hdr_sz = sizeof(union octep_ctrl_mbox_msg_hdr);

static u32 octep_ctrl_mbox_circq_inc(u32 index, u32 inc, u32 sz)
{
        return (index + inc) % sz;
}

static u32 octep_ctrl_mbox_circq_space(u32 pi, u32 ci, u32 sz)
{
        return sz - (abs(pi - ci) % sz);
}

static u32 octep_ctrl_mbox_circq_depth(u32 pi, u32 ci, u32 sz)
{
        return (abs(pi - ci) % sz);
}

int octep_ctrl_mbox_init(struct octep_ctrl_mbox *mbox)
{
        u64 magic_num, status, fw_versions;

        if (!mbox)
                return -EINVAL;

        if (!mbox->barmem) {
                pr_info("octep_ctrl_mbox : Invalid barmem %p\n", mbox->barmem);
                return -EINVAL;
        }

        magic_num = readq(OCTEP_CTRL_MBOX_INFO_MAGIC_NUM(mbox->barmem));
        if (magic_num != OCTEP_CTRL_MBOX_MAGIC_NUMBER) {
                pr_info("octep_ctrl_mbox : Invalid magic number %llx\n", magic_num);
                return -EINVAL;
        }

        status = readq(OCTEP_CTRL_MBOX_INFO_FW_STATUS(mbox->barmem));
        if (status != OCTEP_CTRL_MBOX_STATUS_READY) {
                pr_info("octep_ctrl_mbox : Firmware is not ready.\n");
                return -EINVAL;
        }

        fw_versions = readq(OCTEP_CTRL_MBOX_INFO_FW_VERSION(mbox->barmem));
        mbox->min_fw_version = ((fw_versions & 0xffffffff00000000ull) >> 32);
        mbox->max_fw_version = (fw_versions & 0xffffffff);
        mbox->barmem_sz = readl(OCTEP_CTRL_MBOX_INFO_BARMEM_SZ(mbox->barmem));

        writeq(OCTEP_CTRL_MBOX_STATUS_INIT,
               OCTEP_CTRL_MBOX_INFO_HOST_STATUS(mbox->barmem));

        mutex_init(&mbox->h2fq_lock);
        mutex_init(&mbox->f2hq_lock);

        mbox->h2fq.sz = readl(OCTEP_CTRL_MBOX_H2FQ_SZ(mbox->barmem));
        mbox->h2fq.hw_prod = OCTEP_CTRL_MBOX_H2FQ_PROD(mbox->barmem);
        mbox->h2fq.hw_cons = OCTEP_CTRL_MBOX_H2FQ_CONS(mbox->barmem);
        mbox->h2fq.hw_q = mbox->barmem + OCTEP_CTRL_MBOX_TOTAL_INFO_SZ;

        mbox->f2hq.sz = readl(OCTEP_CTRL_MBOX_F2HQ_SZ(mbox->barmem));
        mbox->f2hq.hw_prod = OCTEP_CTRL_MBOX_F2HQ_PROD(mbox->barmem);
        mbox->f2hq.hw_cons = OCTEP_CTRL_MBOX_F2HQ_CONS(mbox->barmem);
        mbox->f2hq.hw_q = mbox->barmem +
                          OCTEP_CTRL_MBOX_TOTAL_INFO_SZ +
                          mbox->h2fq.sz;

        writeq(mbox->version, OCTEP_CTRL_MBOX_INFO_HOST_VERSION(mbox->barmem));
        /* ensure ready state is seen after everything is initialized */
        wmb();
        writeq(OCTEP_CTRL_MBOX_STATUS_READY,
               OCTEP_CTRL_MBOX_INFO_HOST_STATUS(mbox->barmem));

        pr_info("Octep ctrl mbox : Init successful.\n");

        return 0;
}

static void
octep_write_mbox_data(struct octep_ctrl_mbox_q *q, u32 *pi, u32 ci, void *buf, u32 w_sz)
{
        u8 __iomem *qbuf;
        u32 cp_sz;

        /* Assumption: Caller has ensured enough write space */
        qbuf = (q->hw_q + *pi);
        if (*pi < ci) {
                /* copy entire w_sz */
                memcpy_toio(qbuf, buf, w_sz);
                *pi = octep_ctrl_mbox_circq_inc(*pi, w_sz, q->sz);
        } else {
                /* copy up to end of queue */
                cp_sz = min((q->sz - *pi), w_sz);
                memcpy_toio(qbuf, buf, cp_sz);
                w_sz -= cp_sz;
                *pi = octep_ctrl_mbox_circq_inc(*pi, cp_sz, q->sz);
                if (w_sz) {
                        /* roll over and copy remaining w_sz */
                        buf += cp_sz;
                        qbuf = (q->hw_q + *pi);
                        memcpy_toio(qbuf, buf, w_sz);
                        *pi = octep_ctrl_mbox_circq_inc(*pi, w_sz, q->sz);
                }
        }
}

int octep_ctrl_mbox_send(struct octep_ctrl_mbox *mbox, struct octep_ctrl_mbox_msg *msg)
{
        struct octep_ctrl_mbox_msg_buf *sg;
        struct octep_ctrl_mbox_q *q;
        u32 pi, ci, buf_sz, w_sz;
        int s;

        if (!mbox || !msg)
                return -EINVAL;

        if (readq(OCTEP_CTRL_MBOX_INFO_FW_STATUS(mbox->barmem)) != OCTEP_CTRL_MBOX_STATUS_READY)
                return -EIO;

        mutex_lock(&mbox->h2fq_lock);
        q = &mbox->h2fq;
        pi = readl(q->hw_prod);
        ci = readl(q->hw_cons);

        if (octep_ctrl_mbox_circq_space(pi, ci, q->sz) < (msg->hdr.s.sz + mbox_hdr_sz)) {
                mutex_unlock(&mbox->h2fq_lock);
                return -EAGAIN;
        }

        octep_write_mbox_data(q, &pi, ci, (void *)&msg->hdr, mbox_hdr_sz);
        buf_sz = msg->hdr.s.sz;
        for (s = 0; ((s < msg->sg_num) && (buf_sz > 0)); s++) {
                sg = &msg->sg_list[s];
                w_sz = (sg->sz <= buf_sz) ? sg->sz : buf_sz;
                octep_write_mbox_data(q, &pi, ci, sg->msg, w_sz);
                buf_sz -= w_sz;
        }
        writel(pi, q->hw_prod);
        mutex_unlock(&mbox->h2fq_lock);

        return 0;
}

static void
octep_read_mbox_data(struct octep_ctrl_mbox_q *q, u32 pi, u32 *ci, void *buf, u32 r_sz)
{
        u8 __iomem *qbuf;
        u32 cp_sz;

        /* Assumption: Caller has ensured enough read space */
        qbuf = (q->hw_q + *ci);
        if (*ci < pi) {
                /* copy entire r_sz */
                memcpy_fromio(buf, qbuf, r_sz);
                *ci = octep_ctrl_mbox_circq_inc(*ci, r_sz, q->sz);
        } else {
                /* copy up to end of queue */
                cp_sz = min((q->sz - *ci), r_sz);
                memcpy_fromio(buf, qbuf, cp_sz);
                r_sz -= cp_sz;
                *ci = octep_ctrl_mbox_circq_inc(*ci, cp_sz, q->sz);
                if (r_sz) {
                        /* roll over and copy remaining r_sz */
                        buf += cp_sz;
                        qbuf = (q->hw_q + *ci);
                        memcpy_fromio(buf, qbuf, r_sz);
                        *ci = octep_ctrl_mbox_circq_inc(*ci, r_sz, q->sz);
                }
        }
}

int octep_ctrl_mbox_recv(struct octep_ctrl_mbox *mbox, struct octep_ctrl_mbox_msg *msg)
{
        struct octep_ctrl_mbox_msg_buf *sg;
        u32 pi, ci, r_sz, buf_sz, q_depth;
        struct octep_ctrl_mbox_q *q;
        int s;

        if (readq(OCTEP_CTRL_MBOX_INFO_FW_STATUS(mbox->barmem)) != OCTEP_CTRL_MBOX_STATUS_READY)
                return -EIO;

        mutex_lock(&mbox->f2hq_lock);
        q = &mbox->f2hq;
        pi = readl(q->hw_prod);
        ci = readl(q->hw_cons);

        q_depth = octep_ctrl_mbox_circq_depth(pi, ci, q->sz);
        if (q_depth < mbox_hdr_sz) {
                mutex_unlock(&mbox->f2hq_lock);
                return -EAGAIN;
        }

        octep_read_mbox_data(q, pi, &ci, (void *)&msg->hdr, mbox_hdr_sz);
        buf_sz = msg->hdr.s.sz;
        for (s = 0; ((s < msg->sg_num) && (buf_sz > 0)); s++) {
                sg = &msg->sg_list[s];
                r_sz = (sg->sz <= buf_sz) ? sg->sz : buf_sz;
                octep_read_mbox_data(q, pi, &ci, sg->msg, r_sz);
                buf_sz -= r_sz;
        }
        writel(ci, q->hw_cons);
        mutex_unlock(&mbox->f2hq_lock);

        return 0;
}

int octep_ctrl_mbox_uninit(struct octep_ctrl_mbox *mbox)
{
        if (!mbox)
                return -EINVAL;
        if (!mbox->barmem)
                return -EINVAL;

        writeq(0, OCTEP_CTRL_MBOX_INFO_HOST_VERSION(mbox->barmem));
        writeq(OCTEP_CTRL_MBOX_STATUS_INVALID,
               OCTEP_CTRL_MBOX_INFO_HOST_STATUS(mbox->barmem));
        /* ensure uninit state is written before uninitialization */
        wmb();

        mutex_destroy(&mbox->h2fq_lock);
        mutex_destroy(&mbox->f2hq_lock);

        pr_info("Octep ctrl mbox : Uninit successful.\n");

        return 0;
}