/* Intel(R) Gigabit Ethernet Linux driver
 * Copyright(c) 2007-2014 Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, see <http://www.gnu.org/licenses/>.
 *
 * The full GNU General Public License is included in this distribution in
 * the file called "COPYING".
 *
 * Contact Information:
 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 */

#include "e1000_mbx.h"

/**
 *  igb_read_mbx - Reads a message from the mailbox
 *  @hw: pointer to the HW structure
 *  @msg: The message buffer
 *  @size: Length of buffer
 *  @mbx_id: id of mailbox to read
 *
 *  returns SUCCESS if it successfully read message from buffer
 **/
s32 igb_read_mbx(struct e1000_hw *hw, u32 *msg, u16 size, u16 mbx_id)
{
	struct e1000_mbx_info *mbx = &hw->mbx;
	s32 ret_val = -E1000_ERR_MBX;

	/* limit read to size of mailbox */
	if (size > mbx->size)
		size = mbx->size;

	if (mbx->ops.read)
		ret_val = mbx->ops.read(hw, msg, size, mbx_id);

	return ret_val;
}

/**
 *  igb_write_mbx - Write a message to the mailbox
 *  @hw: pointer to the HW structure
 *  @msg: The message buffer
 *  @size: Length of buffer
 *  @mbx_id: id of mailbox to write
 *
 *  returns SUCCESS if it successfully copied message into the buffer
 **/
s32 igb_write_mbx(struct e1000_hw *hw, u32 *msg, u16 size, u16 mbx_id)
{
	struct e1000_mbx_info *mbx = &hw->mbx;
	s32 ret_val = 0;

	if (size > mbx->size)
		ret_val = -E1000_ERR_MBX;

	else if (mbx->ops.write)
		ret_val = mbx->ops.write(hw, msg, size, mbx_id);

	return ret_val;
}

/**
 *  igb_check_for_msg - checks to see if someone sent us mail
 *  @hw: pointer to the HW structure
 *  @mbx_id: id of mailbox to check
 *
 *  returns SUCCESS if the Status bit was found or else ERR_MBX
 **/
s32 igb_check_for_msg(struct e1000_hw *hw, u16 mbx_id)
{
	struct e1000_mbx_info *mbx = &hw->mbx;
	s32 ret_val = -E1000_ERR_MBX;

	if (mbx->ops.check_for_msg)
		ret_val = mbx->ops.check_for_msg(hw, mbx_id);

	return ret_val;
}

/**
 *  igb_check_for_ack - checks to see if someone sent us ACK
 *  @hw: pointer to the HW structure
 *  @mbx_id: id of mailbox to check
 *
 *  returns SUCCESS if the Status bit was found or else ERR_MBX
 **/
s32 igb_check_for_ack(struct e1000_hw *hw, u16 mbx_id)
{
	struct e1000_mbx_info *mbx = &hw->mbx;
	s32 ret_val = -E1000_ERR_MBX;

	if (mbx->ops.check_for_ack)
		ret_val = mbx->ops.check_for_ack(hw, mbx_id);

	return ret_val;
}

/**
 *  igb_check_for_rst - checks to see if other side has reset
 *  @hw: pointer to the HW structure
 *  @mbx_id: id of mailbox to check
 *
 *  returns SUCCESS if the Status bit was found or else ERR_MBX
 **/
s32 igb_check_for_rst(struct e1000_hw *hw, u16 mbx_id)
{
	struct e1000_mbx_info *mbx = &hw->mbx;
	s32 ret_val = -E1000_ERR_MBX;

	if (mbx->ops.check_for_rst)
		ret_val = mbx->ops.check_for_rst(hw, mbx_id);

	return ret_val;
}

/**
 *  igb_poll_for_msg - Wait for message notification
 *  @hw: pointer to the HW structure
 *  @mbx_id: id of mailbox to write
 *
 *  returns SUCCESS if it successfully received a message notification
 **/
static s32 igb_poll_for_msg(struct e1000_hw *hw, u16 mbx_id)
{
	struct e1000_mbx_info *mbx = &hw->mbx;
	int countdown = mbx->timeout;

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

	while (countdown && mbx->ops.check_for_msg(hw, mbx_id)) {
		countdown--;
		if (!countdown)
			break;
		udelay(mbx->usec_delay);
	}

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

/**
 *  igb_poll_for_ack - Wait for message acknowledgement
 *  @hw: pointer to the HW structure
 *  @mbx_id: id of mailbox to write
 *
 *  returns SUCCESS if it successfully received a message acknowledgement
 **/
static s32 igb_poll_for_ack(struct e1000_hw *hw, u16 mbx_id)
{
	struct e1000_mbx_info *mbx = &hw->mbx;
	int countdown = mbx->timeout;

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

	while (countdown && mbx->ops.check_for_ack(hw, mbx_id)) {
		countdown--;
		if (!countdown)
			break;
		udelay(mbx->usec_delay);
	}

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

/**
 *  igb_read_posted_mbx - Wait for message notification and receive message
 *  @hw: pointer to the HW structure
 *  @msg: The message buffer
 *  @size: Length of buffer
 *  @mbx_id: id of mailbox to write
 *
 *  returns SUCCESS if it successfully received a message notification and
 *  copied it into the receive buffer.
 **/
static s32 igb_read_posted_mbx(struct e1000_hw *hw, u32 *msg, u16 size,
			       u16 mbx_id)
{
	struct e1000_mbx_info *mbx = &hw->mbx;
	s32 ret_val = -E1000_ERR_MBX;

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

	ret_val = igb_poll_for_msg(hw, mbx_id);

	if (!ret_val)
		ret_val = mbx->ops.read(hw, msg, size, mbx_id);
out:
	return ret_val;
}

/**
 *  igb_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
 *  @mbx_id: id of mailbox to write
 *
 *  returns SUCCESS if it successfully copied message into the buffer and
 *  received an ack to that message within delay * timeout period
 **/
static s32 igb_write_posted_mbx(struct e1000_hw *hw, u32 *msg, u16 size,
				u16 mbx_id)
{
	struct e1000_mbx_info *mbx = &hw->mbx;
	s32 ret_val = -E1000_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, mbx_id);

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

static s32 igb_check_for_bit_pf(struct e1000_hw *hw, u32 mask)
{
	u32 mbvficr = rd32(E1000_MBVFICR);
	s32 ret_val = -E1000_ERR_MBX;

	if (mbvficr & mask) {
		ret_val = 0;
		wr32(E1000_MBVFICR, mask);
	}

	return ret_val;
}

/**
 *  igb_check_for_msg_pf - checks to see if the VF has sent mail
 *  @hw: pointer to the HW structure
 *  @vf_number: the VF index
 *
 *  returns SUCCESS if the VF has set the Status bit or else ERR_MBX
 **/
static s32 igb_check_for_msg_pf(struct e1000_hw *hw, u16 vf_number)
{
	s32 ret_val = -E1000_ERR_MBX;

	if (!igb_check_for_bit_pf(hw, E1000_MBVFICR_VFREQ_VF1 << vf_number)) {
		ret_val = 0;
		hw->mbx.stats.reqs++;
	}

	return ret_val;
}

/**
 *  igb_check_for_ack_pf - checks to see if the VF has ACKed
 *  @hw: pointer to the HW structure
 *  @vf_number: the VF index
 *
 *  returns SUCCESS if the VF has set the Status bit or else ERR_MBX
 **/
static s32 igb_check_for_ack_pf(struct e1000_hw *hw, u16 vf_number)
{
	s32 ret_val = -E1000_ERR_MBX;

	if (!igb_check_for_bit_pf(hw, E1000_MBVFICR_VFACK_VF1 << vf_number)) {
		ret_val = 0;
		hw->mbx.stats.acks++;
	}

	return ret_val;
}

/**
 *  igb_check_for_rst_pf - checks to see if the VF has reset
 *  @hw: pointer to the HW structure
 *  @vf_number: the VF index
 *
 *  returns SUCCESS if the VF has set the Status bit or else ERR_MBX
 **/
static s32 igb_check_for_rst_pf(struct e1000_hw *hw, u16 vf_number)
{
	u32 vflre = rd32(E1000_VFLRE);
	s32 ret_val = -E1000_ERR_MBX;

	if (vflre & (1 << vf_number)) {
		ret_val = 0;
		wr32(E1000_VFLRE, (1 << vf_number));
		hw->mbx.stats.rsts++;
	}

	return ret_val;
}

/**
 *  igb_obtain_mbx_lock_pf - obtain mailbox lock
 *  @hw: pointer to the HW structure
 *  @vf_number: the VF index
 *
 *  return SUCCESS if we obtained the mailbox lock
 **/
static s32 igb_obtain_mbx_lock_pf(struct e1000_hw *hw, u16 vf_number)
{
	s32 ret_val = -E1000_ERR_MBX;
	u32 p2v_mailbox;
	int count = 10;

	do {
		/* Take ownership of the buffer */
		wr32(E1000_P2VMAILBOX(vf_number), E1000_P2VMAILBOX_PFU);

		/* reserve mailbox for vf use */
		p2v_mailbox = rd32(E1000_P2VMAILBOX(vf_number));
		if (p2v_mailbox & E1000_P2VMAILBOX_PFU) {
			ret_val = 0;
			break;
		}
		udelay(1000);
	} while (count-- > 0);

	return ret_val;
}

/**
 *  igb_write_mbx_pf - Places a message in the mailbox
 *  @hw: pointer to the HW structure
 *  @msg: The message buffer
 *  @size: Length of buffer
 *  @vf_number: the VF index
 *
 *  returns SUCCESS if it successfully copied message into the buffer
 **/
static s32 igb_write_mbx_pf(struct e1000_hw *hw, u32 *msg, u16 size,
			    u16 vf_number)
{
	s32 ret_val;
	u16 i;

	/* lock the mailbox to prevent pf/vf race condition */
	ret_val = igb_obtain_mbx_lock_pf(hw, vf_number);
	if (ret_val)
		goto out_no_write;

	/* flush msg and acks as we are overwriting the message buffer */
	igb_check_for_msg_pf(hw, vf_number);
	igb_check_for_ack_pf(hw, vf_number);

	/* copy the caller specified message to the mailbox memory buffer */
	for (i = 0; i < size; i++)
		array_wr32(E1000_VMBMEM(vf_number), i, msg[i]);

	/* Interrupt VF to tell it a message has been sent and release buffer*/
	wr32(E1000_P2VMAILBOX(vf_number), E1000_P2VMAILBOX_STS);

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

out_no_write:
	return ret_val;

}

/**
 *  igb_read_mbx_pf - Read a message from the mailbox
 *  @hw: pointer to the HW structure
 *  @msg: The message buffer
 *  @size: Length of buffer
 *  @vf_number: the VF index
 *
 *  This function copies a message from the mailbox buffer to the caller's
 *  memory buffer.  The presumption is that the caller knows that there was
 *  a message due to a VF request so no polling for message is needed.
 **/
static s32 igb_read_mbx_pf(struct e1000_hw *hw, u32 *msg, u16 size,
			   u16 vf_number)
{
	s32 ret_val;
	u16 i;

	/* lock the mailbox to prevent pf/vf race condition */
	ret_val = igb_obtain_mbx_lock_pf(hw, vf_number);
	if (ret_val)
		goto out_no_read;

	/* copy the message to the mailbox memory buffer */
	for (i = 0; i < size; i++)
		msg[i] = array_rd32(E1000_VMBMEM(vf_number), i);

	/* Acknowledge the message and release buffer */
	wr32(E1000_P2VMAILBOX(vf_number), E1000_P2VMAILBOX_ACK);

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

out_no_read:
	return ret_val;
}

/**
 *  e1000_init_mbx_params_pf - set initial values for pf mailbox
 *  @hw: pointer to the HW structure
 *
 *  Initializes the hw->mbx struct to correct values for pf mailbox
 */
s32 igb_init_mbx_params_pf(struct e1000_hw *hw)
{
	struct e1000_mbx_info *mbx = &hw->mbx;

	mbx->timeout = 0;
	mbx->usec_delay = 0;

	mbx->size = E1000_VFMAILBOX_SIZE;

	mbx->ops.read = igb_read_mbx_pf;
	mbx->ops.write = igb_write_mbx_pf;
	mbx->ops.read_posted = igb_read_posted_mbx;
	mbx->ops.write_posted = igb_write_posted_mbx;
	mbx->ops.check_for_msg = igb_check_for_msg_pf;
	mbx->ops.check_for_ack = igb_check_for_ack_pf;
	mbx->ops.check_for_rst = igb_check_for_rst_pf;

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

	return 0;
}