// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 1999 - 2018 Intel Corporation. */

#include "mbx.h"
#include "ixgbevf.h"

/**
 *  ixgbevf_poll_for_msg - Wait for message notification
 *  @hw: pointer to the HW structure
 *
 *  returns 0 if it successfully received a message notification
 **/
static s32 ixgbevf_poll_for_msg(struct ixgbe_hw *hw)
{
        struct ixgbe_mbx_info *mbx = &hw->mbx;
        int countdown = mbx->timeout;

        while (countdown && mbx->ops.check_for_msg(hw)) {
                countdown--;
                udelay(mbx->udelay);
        }

        /* if we failed, all future posted messages fail until reset */
        if (!countdown)
                mbx->timeout = 0;

        return countdown ? 0 : IXGBE_ERR_MBX;
}

/**
 *  ixgbevf_poll_for_ack - Wait for message acknowledgment
 *  @hw: pointer to the HW structure
 *
 *  returns 0 if it successfully received a message acknowledgment
 **/
static s32 ixgbevf_poll_for_ack(struct ixgbe_hw *hw)
{
        struct ixgbe_mbx_info *mbx = &hw->mbx;
        int countdown = mbx->timeout;

        while (countdown && mbx->ops.check_for_ack(hw)) {
                countdown--;
                udelay(mbx->udelay);
        }

        /* if we failed, all future posted messages fail until reset */
        if (!countdown)
                mbx->timeout = 0;

        return countdown ? 0 : IXGBE_ERR_MBX;
}

/**
 *  ixgbevf_read_posted_mbx - Wait for message notification and receive message
 *  @hw: pointer to the HW structure
 *  @msg: The message buffer
 *  @size: Length of buffer
 *
 *  returns 0 if it successfully received a message notification and
 *  copied it into the receive buffer.
 **/
static s32 ixgbevf_read_posted_mbx(struct ixgbe_hw *hw, u32 *msg, u16 size)
{
        struct ixgbe_mbx_info *mbx = &hw->mbx;
        s32 ret_val = IXGBE_ERR_MBX;

        if (!mbx->ops.read)
                goto out;

        ret_val = ixgbevf_poll_for_msg(hw);

        /* if ack received read message, otherwise we timed out */
        if (!ret_val)
                ret_val = mbx->ops.read(hw, msg, size);
out:
        return ret_val;
}

/**
 *  ixgbevf_write_posted_mbx - Write a message to the mailbox, wait for ack
 *  @hw: pointer to the HW structure
 *  @msg: The message buffer
 *  @size: Length of buffer
 *
 *  returns 0 if it successfully copied message into the buffer and
 *  received an ack to that message within delay * timeout period
 **/
static s32 ixgbevf_write_posted_mbx(struct ixgbe_hw *hw, u32 *msg, u16 size)
{
        struct ixgbe_mbx_info *mbx = &hw->mbx;
        s32 ret_val = IXGBE_ERR_MBX;

        /* exit if either we can't write or there isn't a defined timeout */
        if (!mbx->ops.write || !mbx->timeout)
                goto out;

        /* send msg */
        ret_val = mbx->ops.write(hw, msg, size);

        /* if msg sent wait until we receive an ack */
        if (!ret_val)
                ret_val = ixgbevf_poll_for_ack(hw);
out:
        return ret_val;
}

/**
 *  ixgbevf_read_v2p_mailbox - read v2p mailbox
 *  @hw: pointer to the HW structure
 *
 *  This function is used to read the v2p mailbox without losing the read to
 *  clear status bits.
 **/
static u32 ixgbevf_read_v2p_mailbox(struct ixgbe_hw *hw)
{
        u32 v2p_mailbox = IXGBE_READ_REG(hw, IXGBE_VFMAILBOX);

        v2p_mailbox |= hw->mbx.v2p_mailbox;
        hw->mbx.v2p_mailbox |= v2p_mailbox & IXGBE_VFMAILBOX_R2C_BITS;

        return v2p_mailbox;
}

/**
 *  ixgbevf_check_for_bit_vf - Determine if a status bit was set
 *  @hw: pointer to the HW structure
 *  @mask: bitmask for bits to be tested and cleared
 *
 *  This function is used to check for the read to clear bits within
 *  the V2P mailbox.
 **/
static s32 ixgbevf_check_for_bit_vf(struct ixgbe_hw *hw, u32 mask)
{
        u32 v2p_mailbox = ixgbevf_read_v2p_mailbox(hw);
        s32 ret_val = IXGBE_ERR_MBX;

        if (v2p_mailbox & mask)
                ret_val = 0;

        hw->mbx.v2p_mailbox &= ~mask;

        return ret_val;
}

/**
 *  ixgbevf_check_for_msg_vf - checks to see if the PF has sent mail
 *  @hw: pointer to the HW structure
 *
 *  returns 0 if the PF has set the Status bit or else ERR_MBX
 **/
static s32 ixgbevf_check_for_msg_vf(struct ixgbe_hw *hw)
{
        s32 ret_val = IXGBE_ERR_MBX;

        if (!ixgbevf_check_for_bit_vf(hw, IXGBE_VFMAILBOX_PFSTS)) {
                ret_val = 0;
                hw->mbx.stats.reqs++;
        }

        return ret_val;
}

/**
 *  ixgbevf_check_for_ack_vf - checks to see if the PF has ACK'd
 *  @hw: pointer to the HW structure
 *
 *  returns 0 if the PF has set the ACK bit or else ERR_MBX
 **/
static s32 ixgbevf_check_for_ack_vf(struct ixgbe_hw *hw)
{
        s32 ret_val = IXGBE_ERR_MBX;

        if (!ixgbevf_check_for_bit_vf(hw, IXGBE_VFMAILBOX_PFACK)) {
                ret_val = 0;
                hw->mbx.stats.acks++;
        }

        return ret_val;
}

/**
 *  ixgbevf_check_for_rst_vf - checks to see if the PF has reset
 *  @hw: pointer to the HW structure
 *
 *  returns true if the PF has set the reset done bit or else false
 **/
static s32 ixgbevf_check_for_rst_vf(struct ixgbe_hw *hw)
{
        s32 ret_val = IXGBE_ERR_MBX;

        if (!ixgbevf_check_for_bit_vf(hw, (IXGBE_VFMAILBOX_RSTD |
                                           IXGBE_VFMAILBOX_RSTI))) {
                ret_val = 0;
                hw->mbx.stats.rsts++;
        }

        return ret_val;
}

/**
 *  ixgbevf_obtain_mbx_lock_vf - obtain mailbox lock
 *  @hw: pointer to the HW structure
 *
 *  return 0 if we obtained the mailbox lock
 **/
static s32 ixgbevf_obtain_mbx_lock_vf(struct ixgbe_hw *hw)
{
        s32 ret_val = IXGBE_ERR_MBX;

        /* Take ownership of the buffer */
        IXGBE_WRITE_REG(hw, IXGBE_VFMAILBOX, IXGBE_VFMAILBOX_VFU);

        /* reserve mailbox for VF use */
        if (ixgbevf_read_v2p_mailbox(hw) & IXGBE_VFMAILBOX_VFU)
                ret_val = 0;

        return ret_val;
}

/**
 *  ixgbevf_write_mbx_vf - Write a message to the mailbox
 *  @hw: pointer to the HW structure
 *  @msg: The message buffer
 *  @size: Length of buffer
 *
 *  returns 0 if it successfully copied message into the buffer
 **/
static s32 ixgbevf_write_mbx_vf(struct ixgbe_hw *hw, u32 *msg, u16 size)
{
        s32 ret_val;
        u16 i;

        /* lock the mailbox to prevent PF/VF race condition */
        ret_val = ixgbevf_obtain_mbx_lock_vf(hw);
        if (ret_val)
                goto out_no_write;

        /* flush msg and acks as we are overwriting the message buffer */
        ixgbevf_check_for_msg_vf(hw);
        ixgbevf_check_for_ack_vf(hw);

        /* copy the caller specified message to the mailbox memory buffer */
        for (i = 0; i < size; i++)
                IXGBE_WRITE_REG_ARRAY(hw, IXGBE_VFMBMEM, i, msg[i]);

        /* update stats */
        hw->mbx.stats.msgs_tx++;

        /* Drop VFU and interrupt the PF to tell it a message has been sent */
        IXGBE_WRITE_REG(hw, IXGBE_VFMAILBOX, IXGBE_VFMAILBOX_REQ);

out_no_write:
        return ret_val;
}

/**
 *  ixgbevf_read_mbx_vf - Reads a message from the inbox intended for VF
 *  @hw: pointer to the HW structure
 *  @msg: The message buffer
 *  @size: Length of buffer
 *
 *  returns 0 if it successfully read message from buffer
 **/
static s32 ixgbevf_read_mbx_vf(struct ixgbe_hw *hw, u32 *msg, u16 size)
{
        s32 ret_val = 0;
        u16 i;

        /* lock the mailbox to prevent PF/VF race condition */
        ret_val = ixgbevf_obtain_mbx_lock_vf(hw);
        if (ret_val)
                goto out_no_read;

        /* copy the message from the mailbox memory buffer */
        for (i = 0; i < size; i++)
                msg[i] = IXGBE_READ_REG_ARRAY(hw, IXGBE_VFMBMEM, i);

        /* Acknowledge receipt and release mailbox, then we're done */
        IXGBE_WRITE_REG(hw, IXGBE_VFMAILBOX, IXGBE_VFMAILBOX_ACK);

        /* update stats */
        hw->mbx.stats.msgs_rx++;

out_no_read:
        return ret_val;
}

/**
 *  ixgbevf_init_mbx_params_vf - set initial values for VF mailbox
 *  @hw: pointer to the HW structure
 *
 *  Initializes the hw->mbx struct to correct values for VF mailbox
 */
static s32 ixgbevf_init_mbx_params_vf(struct ixgbe_hw *hw)
{
        struct ixgbe_mbx_info *mbx = &hw->mbx;

        /* start mailbox as timed out and let the reset_hw call set the timeout
         * value to begin communications
         */
        mbx->timeout = 0;
        mbx->udelay = IXGBE_VF_MBX_INIT_DELAY;

        mbx->size = IXGBE_VFMAILBOX_SIZE;

        mbx->stats.msgs_tx = 0;
        mbx->stats.msgs_rx = 0;
        mbx->stats.reqs = 0;
        mbx->stats.acks = 0;
        mbx->stats.rsts = 0;

        return 0;
}

const struct ixgbe_mbx_operations ixgbevf_mbx_ops = {
        .init_params    = ixgbevf_init_mbx_params_vf,
        .read           = ixgbevf_read_mbx_vf,
        .write          = ixgbevf_write_mbx_vf,
        .read_posted    = ixgbevf_read_posted_mbx,
        .write_posted   = ixgbevf_write_posted_mbx,
        .check_for_msg  = ixgbevf_check_for_msg_vf,
        .check_for_ack  = ixgbevf_check_for_ack_vf,
        .check_for_rst  = ixgbevf_check_for_rst_vf,
};

/* Mailbox operations when running on Hyper-V.
 * On Hyper-V, PF/VF communication is not through the
 * hardware mailbox; this communication is through
 * a software mediated path.
 * Most mail box operations are noop while running on
 * Hyper-V.
 */
const struct ixgbe_mbx_operations ixgbevf_hv_mbx_ops = {
        .init_params    = ixgbevf_init_mbx_params_vf,
        .check_for_rst  = ixgbevf_check_for_rst_vf,
};