// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2009 - 2018 Intel Corporation. */

#include <linux/bitfield.h>
#include "mbx.h"

/**
 *  e1000_poll_for_msg - Wait for message notification
 *  @hw: pointer to the HW structure
 *
 *  returns SUCCESS if it successfully received a message notification
 **/
static s32 e1000_poll_for_msg(struct e1000_hw *hw)
{
        struct e1000_mbx_info *mbx = &hw->mbx;
        int countdown = mbx->timeout;

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

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

        /* if we failed, all future posted messages fail until reset */
        if (!countdown)
                mbx->timeout = 0;
out:
        return countdown ? E1000_SUCCESS : -E1000_ERR_MBX;
}

/**
 *  e1000_poll_for_ack - Wait for message acknowledgment
 *  @hw: pointer to the HW structure
 *
 *  returns SUCCESS if it successfully received a message acknowledgment
 **/
static s32 e1000_poll_for_ack(struct e1000_hw *hw)
{
        struct e1000_mbx_info *mbx = &hw->mbx;
        int countdown = mbx->timeout;

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

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

        /* if we failed, all future posted messages fail until reset */
        if (!countdown)
                mbx->timeout = 0;
out:
        return countdown ? E1000_SUCCESS : -E1000_ERR_MBX;
}

/**
 *  e1000_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 SUCCESS if it successfully received a message notification and
 *  copied it into the receive buffer.
 **/
static s32 e1000_read_posted_mbx(struct e1000_hw *hw, u32 *msg, u16 size)
{
        struct e1000_mbx_info *mbx = &hw->mbx;
        s32 ret_val = -E1000_ERR_MBX;

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

        ret_val = e1000_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;
}

/**
 *  e1000_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 SUCCESS if it successfully copied message into the buffer and
 *  received an ack to that message within delay * timeout period
 **/
static s32 e1000_write_posted_mbx(struct e1000_hw *hw, u32 *msg, u16 size)
{
        struct e1000_mbx_info *mbx = &hw->mbx;
        s32 ret_val = -E1000_ERR_MBX;

        /* exit if we either 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 = e1000_poll_for_ack(hw);
out:
        return ret_val;
}

/**
 *  e1000_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 e1000_read_v2p_mailbox(struct e1000_hw *hw)
{
        u32 v2p_mailbox = er32(V2PMAILBOX(0));

        v2p_mailbox |= hw->dev_spec.vf.v2p_mailbox;
        hw->dev_spec.vf.v2p_mailbox |= v2p_mailbox & E1000_V2PMAILBOX_R2C_BITS;

        return v2p_mailbox;
}

/**
 *  e1000_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 e1000_check_for_bit_vf(struct e1000_hw *hw, u32 mask)
{
        u32 v2p_mailbox = e1000_read_v2p_mailbox(hw);
        s32 ret_val = -E1000_ERR_MBX;

        if (v2p_mailbox & mask)
                ret_val = E1000_SUCCESS;

        hw->dev_spec.vf.v2p_mailbox &= ~mask;

        return ret_val;
}

/**
 *  e1000_check_for_msg_vf - checks to see if the PF has sent mail
 *  @hw: pointer to the HW structure
 *
 *  returns SUCCESS if the PF has set the Status bit or else ERR_MBX
 **/
static s32 e1000_check_for_msg_vf(struct e1000_hw *hw)
{
        s32 ret_val = -E1000_ERR_MBX;

        if (!e1000_check_for_bit_vf(hw, E1000_V2PMAILBOX_PFSTS)) {
                ret_val = E1000_SUCCESS;
                hw->mbx.stats.reqs++;
        }

        return ret_val;
}

/**
 *  e1000_check_for_ack_vf - checks to see if the PF has ACK'd
 *  @hw: pointer to the HW structure
 *
 *  returns SUCCESS if the PF has set the ACK bit or else ERR_MBX
 **/
static s32 e1000_check_for_ack_vf(struct e1000_hw *hw)
{
        s32 ret_val = -E1000_ERR_MBX;

        if (!e1000_check_for_bit_vf(hw, E1000_V2PMAILBOX_PFACK)) {
                ret_val = E1000_SUCCESS;
                hw->mbx.stats.acks++;
        }

        return ret_val;
}

/**
 *  e1000_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 e1000_check_for_rst_vf(struct e1000_hw *hw)
{
        s32 ret_val = -E1000_ERR_MBX;

        if (!e1000_check_for_bit_vf(hw, (E1000_V2PMAILBOX_RSTD |
                                         E1000_V2PMAILBOX_RSTI))) {
                ret_val = E1000_SUCCESS;
                hw->mbx.stats.rsts++;
        }

        return ret_val;
}

/**
 *  e1000_obtain_mbx_lock_vf - obtain mailbox lock
 *  @hw: pointer to the HW structure
 *
 *  return SUCCESS if we obtained the mailbox lock
 **/
static s32 e1000_obtain_mbx_lock_vf(struct e1000_hw *hw)
{
        s32 ret_val = -E1000_ERR_MBX;
        int count = 10;

        do {
                /* Take ownership of the buffer */
                ew32(V2PMAILBOX(0), E1000_V2PMAILBOX_VFU);

                /* reserve mailbox for VF use */
                if (e1000_read_v2p_mailbox(hw) & E1000_V2PMAILBOX_VFU) {
                        ret_val = 0;
                        break;
                }
                udelay(1000);
        } while (count-- > 0);

        return ret_val;
}

/**
 *  e1000_write_mbx_vf - Write a message to the mailbox
 *  @hw: pointer to the HW structure
 *  @msg: The message buffer
 *  @size: Length of buffer
 *
 *  returns SUCCESS if it successfully copied message into the buffer
 **/
static s32 e1000_write_mbx_vf(struct e1000_hw *hw, u32 *msg, u16 size)
{
        s32 err;
        u16 i;

        lockdep_assert_held(&hw->mbx_lock);

        /* lock the mailbox to prevent pf/vf race condition */
        err = e1000_obtain_mbx_lock_vf(hw);
        if (err)
                goto out_no_write;

        /* flush any ack or msg as we are going to overwrite mailbox */
        e1000_check_for_ack_vf(hw);
        e1000_check_for_msg_vf(hw);

        /* copy the caller specified message to the mailbox memory buffer */
        for (i = 0; i < size; i++)
                array_ew32(VMBMEM(0), i, msg[i]);

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

        /* Drop VFU and interrupt the PF to tell it a message has been sent */
        ew32(V2PMAILBOX(0), E1000_V2PMAILBOX_REQ);

out_no_write:
        return err;
}

/**
 *  e1000_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 SUCCESS if it successfully read message from buffer
 **/
static s32 e1000_read_mbx_vf(struct e1000_hw *hw, u32 *msg, u16 size)
{
        s32 err;
        u16 i;

        lockdep_assert_held(&hw->mbx_lock);

        /* lock the mailbox to prevent pf/vf race condition */
        err = e1000_obtain_mbx_lock_vf(hw);
        if (err)
                goto out_no_read;

        /* copy the message from the mailbox memory buffer */
        for (i = 0; i < size; i++)
                msg[i] = array_er32(VMBMEM(0), i);

        /* Acknowledge receipt and release mailbox, then we're done */
        ew32(V2PMAILBOX(0), E1000_V2PMAILBOX_ACK);

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

out_no_read:
        return err;
}

/**
 *  e1000_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
 */
s32 e1000_init_mbx_params_vf(struct e1000_hw *hw)
{
        struct e1000_mbx_info *mbx = &hw->mbx;

        /* start mailbox as timed out and let the reset_hw call set the timeout
         * value to being communications
         */
        mbx->timeout = 0;
        mbx->usec_delay = E1000_VF_MBX_INIT_DELAY;

        mbx->size = E1000_VFMAILBOX_SIZE;

        mbx->ops.read = e1000_read_mbx_vf;
        mbx->ops.write = e1000_write_mbx_vf;
        mbx->ops.read_posted = e1000_read_posted_mbx;
        mbx->ops.write_posted = e1000_write_posted_mbx;
        mbx->ops.check_for_msg = e1000_check_for_msg_vf;
        mbx->ops.check_for_ack = e1000_check_for_ack_vf;
        mbx->ops.check_for_rst = e1000_check_for_rst_vf;

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

        return E1000_SUCCESS;
}