drivers/net/ethernet/amd/xgbe/xgbe-i2c.c - linux-mtk - Git at Google

 /*
  * AMD 10Gb Ethernet driver
  *
  * This file is available to you under your choice of the following two
  * licenses:
  *
  * License 1: GPLv2
  *
  * Copyright (c) 2016 Advanced Micro Devices, Inc.
  *
  * This file is free software; you may copy, redistribute and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 2 of the License, or (at
  * your option) any later version.
  *
  * This file is distributed in the hope that 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/>.
  *
  * This file incorporates work covered by the following copyright and
  * permission notice:
  *     The Synopsys DWC ETHER XGMAC Software Driver and documentation
  *     (hereinafter "Software") is an unsupported proprietary work of Synopsys,
  *     Inc. unless otherwise expressly agreed to in writing between Synopsys
  *     and you.
  *
  *     The Software IS NOT an item of Licensed Software or Licensed Product
  *     under any End User Software License Agreement or Agreement for Licensed
  *     Product with Synopsys or any supplement thereto.  Permission is hereby
  *     granted, free of charge, to any person obtaining a copy of this software
  *     annotated with this license and the Software, to deal in the Software
  *     without restriction, including without limitation the rights to use,
  *     copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  *     of the Software, and to permit persons to whom the Software is furnished
  *     to do so, subject to the following conditions:
  *
  *     The above copyright notice and this permission notice shall be included
  *     in all copies or substantial portions of the Software.
  *
  *     THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS"
  *     BASIS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  *     TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  *     PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS
  *     BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  *     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  *     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  *     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  *     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  *     THE POSSIBILITY OF SUCH DAMAGE.
  *
  *
  * License 2: Modified BSD
  *
  * Copyright (c) 2016 Advanced Micro Devices, Inc.
  * All rights reserved.
  *
  * 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.
  *     * Neither the name of Advanced Micro Devices, Inc. nor the
  *       names of its contributors may be used to endorse or promote products
  *       derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * This file incorporates work covered by the following copyright and
  * permission notice:
  *     The Synopsys DWC ETHER XGMAC Software Driver and documentation
  *     (hereinafter "Software") is an unsupported proprietary work of Synopsys,
  *     Inc. unless otherwise expressly agreed to in writing between Synopsys
  *     and you.
  *
  *     The Software IS NOT an item of Licensed Software or Licensed Product
  *     under any End User Software License Agreement or Agreement for Licensed
  *     Product with Synopsys or any supplement thereto.  Permission is hereby
  *     granted, free of charge, to any person obtaining a copy of this software
  *     annotated with this license and the Software, to deal in the Software
  *     without restriction, including without limitation the rights to use,
  *     copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  *     of the Software, and to permit persons to whom the Software is furnished
  *     to do so, subject to the following conditions:
  *
  *     The above copyright notice and this permission notice shall be included
  *     in all copies or substantial portions of the Software.
  *
  *     THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS"
  *     BASIS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  *     TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  *     PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS
  *     BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  *     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  *     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  *     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  *     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  *     THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/kmod.h>
 #include <linux/delay.h>
 #include <linux/completion.h>
 #include <linux/mutex.h>

 #include "xgbe.h"
 #include "xgbe-common.h"

 #define XGBE_ABORT_COUNT	500
 #define XGBE_DISABLE_COUNT	1000

 #define XGBE_STD_SPEED		1

 #define XGBE_INTR_RX_FULL	BIT(IC_RAW_INTR_STAT_RX_FULL_INDEX)
 #define XGBE_INTR_TX_EMPTY	BIT(IC_RAW_INTR_STAT_TX_EMPTY_INDEX)
 #define XGBE_INTR_TX_ABRT	BIT(IC_RAW_INTR_STAT_TX_ABRT_INDEX)
 #define XGBE_INTR_STOP_DET	BIT(IC_RAW_INTR_STAT_STOP_DET_INDEX)
 #define XGBE_DEFAULT_INT_MASK	(XGBE_INTR_RX_FULL  |	\
 				 XGBE_INTR_TX_EMPTY |	\
 				 XGBE_INTR_TX_ABRT  |	\
 				 XGBE_INTR_STOP_DET)

 #define XGBE_I2C_READ		BIT(8)
 #define XGBE_I2C_STOP		BIT(9)

 static int xgbe_i2c_abort(struct xgbe_prv_data *pdata)
 {
 	unsigned int wait = XGBE_ABORT_COUNT;

 	/* Must be enabled to recognize the abort request */
 	XI2C_IOWRITE_BITS(pdata, IC_ENABLE, EN, 1);

 	/* Issue the abort */
 	XI2C_IOWRITE_BITS(pdata, IC_ENABLE, ABORT, 1);

 	while (wait--) {
 		if (!XI2C_IOREAD_BITS(pdata, IC_ENABLE, ABORT))
 			return 0;

 		usleep_range(500, 600);
 	}

 	return -EBUSY;
 }

 static int xgbe_i2c_set_enable(struct xgbe_prv_data *pdata, bool enable)
 {
 	unsigned int wait = XGBE_DISABLE_COUNT;
 	unsigned int mode = enable ? 1 : 0;

 	while (wait--) {
 		XI2C_IOWRITE_BITS(pdata, IC_ENABLE, EN, mode);
 		if (XI2C_IOREAD_BITS(pdata, IC_ENABLE_STATUS, EN) == mode)
 			return 0;

 		usleep_range(100, 110);
 	}

 	return -EBUSY;
 }

 static int xgbe_i2c_disable(struct xgbe_prv_data *pdata)
 {
 	unsigned int ret;

 	ret = xgbe_i2c_set_enable(pdata, false);
 	if (ret) {
 		/* Disable failed, try an abort */
 		ret = xgbe_i2c_abort(pdata);
 		if (ret)
 			return ret;

 		/* Abort succeeded, try to disable again */
 		ret = xgbe_i2c_set_enable(pdata, false);
 	}

 	return ret;
 }

 static int xgbe_i2c_enable(struct xgbe_prv_data *pdata)
 {
 	return xgbe_i2c_set_enable(pdata, true);
 }

 static void xgbe_i2c_clear_all_interrupts(struct xgbe_prv_data *pdata)
 {
 	XI2C_IOREAD(pdata, IC_CLR_INTR);
 }

 static void xgbe_i2c_disable_interrupts(struct xgbe_prv_data *pdata)
 {
 	XI2C_IOWRITE(pdata, IC_INTR_MASK, 0);
 }

 static void xgbe_i2c_enable_interrupts(struct xgbe_prv_data *pdata)
 {
 	XI2C_IOWRITE(pdata, IC_INTR_MASK, XGBE_DEFAULT_INT_MASK);
 }

 static void xgbe_i2c_write(struct xgbe_prv_data *pdata)
 {
 	struct xgbe_i2c_op_state *state = &pdata->i2c.op_state;
 	unsigned int tx_slots;
 	unsigned int cmd;

 	/* Configured to never receive Rx overflows, so fill up Tx fifo */
 	tx_slots = pdata->i2c.tx_fifo_size - XI2C_IOREAD(pdata, IC_TXFLR);
 	while (tx_slots && state->tx_len) {
 		if (state->op->cmd == XGBE_I2C_CMD_READ)
 			cmd = XGBE_I2C_READ;
 		else
 			cmd = *state->tx_buf++;

 		if (state->tx_len == 1)
 			XI2C_SET_BITS(cmd, IC_DATA_CMD, STOP, 1);

 		XI2C_IOWRITE(pdata, IC_DATA_CMD, cmd);

 		tx_slots--;
 		state->tx_len--;
 	}

 	/* No more Tx operations, so ignore TX_EMPTY and return */
 	if (!state->tx_len)
 		XI2C_IOWRITE_BITS(pdata, IC_INTR_MASK, TX_EMPTY, 0);
 }

 static void xgbe_i2c_read(struct xgbe_prv_data *pdata)
 {
 	struct xgbe_i2c_op_state *state = &pdata->i2c.op_state;
 	unsigned int rx_slots;

 	/* Anything to be read? */
 	if (state->op->cmd != XGBE_I2C_CMD_READ)
 		return;

 	rx_slots = XI2C_IOREAD(pdata, IC_RXFLR);
 	while (rx_slots && state->rx_len) {
 		*state->rx_buf++ = XI2C_IOREAD(pdata, IC_DATA_CMD);
 		state->rx_len--;
 		rx_slots--;
 	}
 }

 static void xgbe_i2c_clear_isr_interrupts(struct xgbe_prv_data *pdata,
 					  unsigned int isr)
 {
 	struct xgbe_i2c_op_state *state = &pdata->i2c.op_state;

 	if (isr & XGBE_INTR_TX_ABRT) {
 		state->tx_abort_source = XI2C_IOREAD(pdata, IC_TX_ABRT_SOURCE);
 		XI2C_IOREAD(pdata, IC_CLR_TX_ABRT);
 	}

 	if (isr & XGBE_INTR_STOP_DET)
 		XI2C_IOREAD(pdata, IC_CLR_STOP_DET);
 }

 static void xgbe_i2c_isr_task(unsigned long data)
 {
 	struct xgbe_prv_data *pdata = (struct xgbe_prv_data *)data;
 	struct xgbe_i2c_op_state *state = &pdata->i2c.op_state;
 	unsigned int isr;

 	isr = XI2C_IOREAD(pdata, IC_RAW_INTR_STAT);
 	if (!isr)
 		goto reissue_check;

 	netif_dbg(pdata, intr, pdata->netdev,
 		  "I2C interrupt received: status=%#010x\n", isr);

 	xgbe_i2c_clear_isr_interrupts(pdata, isr);

 	if (isr & XGBE_INTR_TX_ABRT) {
 		netif_dbg(pdata, link, pdata->netdev,
 			  "I2C TX_ABRT received (%#010x) for target %#04x\n",
 			  state->tx_abort_source, state->op->target);

 		xgbe_i2c_disable_interrupts(pdata);

 		state->ret = -EIO;
 		goto out;
 	}

 	/* Check for data in the Rx fifo */
 	xgbe_i2c_read(pdata);

 	/* Fill up the Tx fifo next */
 	xgbe_i2c_write(pdata);

 out:
 	/* Complete on an error or STOP condition */
 	if (state->ret || XI2C_GET_BITS(isr, IC_RAW_INTR_STAT, STOP_DET))
 		complete(&pdata->i2c_complete);

 reissue_check:
 	/* Reissue interrupt if status is not clear */
 	if (pdata->vdata->irq_reissue_support)
 		XP_IOWRITE(pdata, XP_INT_REISSUE_EN, 1 << 2);
 }

 static irqreturn_t xgbe_i2c_isr(int irq, void *data)
 {
 	struct xgbe_prv_data *pdata = (struct xgbe_prv_data *)data;

 	if (pdata->isr_as_tasklet)
 		tasklet_schedule(&pdata->tasklet_i2c);
 	else
 		xgbe_i2c_isr_task((unsigned long)pdata);

 	return IRQ_HANDLED;
 }

 static void xgbe_i2c_set_mode(struct xgbe_prv_data *pdata)
 {
 	unsigned int reg;

 	reg = XI2C_IOREAD(pdata, IC_CON);
 	XI2C_SET_BITS(reg, IC_CON, MASTER_MODE, 1);
 	XI2C_SET_BITS(reg, IC_CON, SLAVE_DISABLE, 1);
 	XI2C_SET_BITS(reg, IC_CON, RESTART_EN, 1);
 	XI2C_SET_BITS(reg, IC_CON, SPEED, XGBE_STD_SPEED);
 	XI2C_SET_BITS(reg, IC_CON, RX_FIFO_FULL_HOLD, 1);
 	XI2C_IOWRITE(pdata, IC_CON, reg);
 }

 static void xgbe_i2c_get_features(struct xgbe_prv_data *pdata)
 {
 	struct xgbe_i2c *i2c = &pdata->i2c;
 	unsigned int reg;

 	reg = XI2C_IOREAD(pdata, IC_COMP_PARAM_1);
 	i2c->max_speed_mode = XI2C_GET_BITS(reg, IC_COMP_PARAM_1,
 					    MAX_SPEED_MODE);
 	i2c->rx_fifo_size = XI2C_GET_BITS(reg, IC_COMP_PARAM_1,
 					  RX_BUFFER_DEPTH);
 	i2c->tx_fifo_size = XI2C_GET_BITS(reg, IC_COMP_PARAM_1,
 					  TX_BUFFER_DEPTH);

 	if (netif_msg_probe(pdata))
 		dev_dbg(pdata->dev, "I2C features: %s=%u, %s=%u, %s=%u\n",
 			"MAX_SPEED_MODE", i2c->max_speed_mode,
 			"RX_BUFFER_DEPTH", i2c->rx_fifo_size,
 			"TX_BUFFER_DEPTH", i2c->tx_fifo_size);
 }

 static void xgbe_i2c_set_target(struct xgbe_prv_data *pdata, unsigned int addr)
 {
 	XI2C_IOWRITE(pdata, IC_TAR, addr);
 }

 static irqreturn_t xgbe_i2c_combined_isr(struct xgbe_prv_data *pdata)
 {
 	xgbe_i2c_isr_task((unsigned long)pdata);

 	return IRQ_HANDLED;
 }

 static int xgbe_i2c_xfer(struct xgbe_prv_data *pdata, struct xgbe_i2c_op *op)
 {
 	struct xgbe_i2c_op_state *state = &pdata->i2c.op_state;
 	int ret;

 	mutex_lock(&pdata->i2c_mutex);

 	reinit_completion(&pdata->i2c_complete);

 	ret = xgbe_i2c_disable(pdata);
 	if (ret) {
 		netdev_err(pdata->netdev, "failed to disable i2c master\n");
 		goto unlock;
 	}

 	xgbe_i2c_set_target(pdata, op->target);

 	memset(state, 0, sizeof(*state));
 	state->op = op;
 	state->tx_len = op->len;
 	state->tx_buf = op->buf;
 	state->rx_len = op->len;
 	state->rx_buf = op->buf;

 	xgbe_i2c_clear_all_interrupts(pdata);
 	ret = xgbe_i2c_enable(pdata);
 	if (ret) {
 		netdev_err(pdata->netdev, "failed to enable i2c master\n");
 		goto unlock;
 	}

 	/* Enabling the interrupts will cause the TX FIFO empty interrupt to
 	 * fire and begin to process the command via the ISR.
 	 */
 	xgbe_i2c_enable_interrupts(pdata);

 	if (!wait_for_completion_timeout(&pdata->i2c_complete, HZ)) {
 		netdev_err(pdata->netdev, "i2c operation timed out\n");
 		ret = -ETIMEDOUT;
 		goto disable;
 	}

 	ret = state->ret;
 	if (ret) {
 		if (state->tx_abort_source & IC_TX_ABRT_7B_ADDR_NOACK)
 			ret = -ENOTCONN;
 		else if (state->tx_abort_source & IC_TX_ABRT_ARB_LOST)
 			ret = -EAGAIN;
 	}

 disable:
 	xgbe_i2c_disable_interrupts(pdata);
 	xgbe_i2c_disable(pdata);

 unlock:
 	mutex_unlock(&pdata->i2c_mutex);

 	return ret;
 }

 static void xgbe_i2c_stop(struct xgbe_prv_data *pdata)
 {
 	if (!pdata->i2c.started)
 		return;

 	netif_dbg(pdata, link, pdata->netdev, "stopping I2C\n");

 	pdata->i2c.started = 0;

 	xgbe_i2c_disable_interrupts(pdata);
 	xgbe_i2c_disable(pdata);
 	xgbe_i2c_clear_all_interrupts(pdata);

 	if (pdata->dev_irq != pdata->i2c_irq)
 		devm_free_irq(pdata->dev, pdata->i2c_irq, pdata);
 }

 static int xgbe_i2c_start(struct xgbe_prv_data *pdata)
 {
 	int ret;

 	if (pdata->i2c.started)
 		return 0;

 	netif_dbg(pdata, link, pdata->netdev, "starting I2C\n");

 	/* If we have a separate I2C irq, enable it */
 	if (pdata->dev_irq != pdata->i2c_irq) {
 		tasklet_init(&pdata->tasklet_i2c, xgbe_i2c_isr_task,
 			     (unsigned long)pdata);

 		ret = devm_request_irq(pdata->dev, pdata->i2c_irq,
 				       xgbe_i2c_isr, 0, pdata->i2c_name,
 				       pdata);
 		if (ret) {
 			netdev_err(pdata->netdev, "i2c irq request failed\n");
 			return ret;
 		}
 	}

 	pdata->i2c.started = 1;

 	return 0;
 }

 static int xgbe_i2c_init(struct xgbe_prv_data *pdata)
 {
 	int ret;

 	xgbe_i2c_disable_interrupts(pdata);

 	ret = xgbe_i2c_disable(pdata);
 	if (ret) {
 		dev_err(pdata->dev, "failed to disable i2c master\n");
 		return ret;
 	}

 	xgbe_i2c_get_features(pdata);

 	xgbe_i2c_set_mode(pdata);

 	xgbe_i2c_clear_all_interrupts(pdata);

 	return 0;
 }

 void xgbe_init_function_ptrs_i2c(struct xgbe_i2c_if *i2c_if)
 {
 	i2c_if->i2c_init		= xgbe_i2c_init;

 	i2c_if->i2c_start		= xgbe_i2c_start;
 	i2c_if->i2c_stop		= xgbe_i2c_stop;

 	i2c_if->i2c_xfer		= xgbe_i2c_xfer;

 	i2c_if->i2c_isr			= xgbe_i2c_combined_isr;
 }
	/*
	* AMD 10Gb Ethernet driver
	*
	* This file is available to you under your choice of the following two
	* licenses:
	*
	* License 1: GPLv2
	*
	* Copyright (c) 2016 Advanced Micro Devices, Inc.
	*
	* This file is free software; you may copy, redistribute and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, either version 2 of the License, or (at
	* your option) any later version.
	*
	* This file is distributed in the hope that 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/>.
	*
	* This file incorporates work covered by the following copyright and
	* permission notice:
	* The Synopsys DWC ETHER XGMAC Software Driver and documentation
	* (hereinafter "Software") is an unsupported proprietary work of Synopsys,
	* Inc. unless otherwise expressly agreed to in writing between Synopsys
	* and you.
	*
	* The Software IS NOT an item of Licensed Software or Licensed Product
	* under any End User Software License Agreement or Agreement for Licensed
	* Product with Synopsys or any supplement thereto. Permission is hereby
	* granted, free of charge, to any person obtaining a copy of this software
	* annotated with this license and the Software, to deal in the Software
	* without restriction, including without limitation the rights to use,
	* copy, modify, merge, publish, distribute, sublicense, and/or sell copies
	* of the Software, and to permit persons to whom the Software is furnished
	* to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included
	* in all copies or substantial portions of the Software.
	*
	* THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS"
	* BASIS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
	* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	* PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS
	* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
	* THE POSSIBILITY OF SUCH DAMAGE.
	*
	*
	* License 2: Modified BSD
	*
	* Copyright (c) 2016 Advanced Micro Devices, Inc.
	* All rights reserved.
	*
	* 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.
	* * Neither the name of Advanced Micro Devices, Inc. nor the
	* names of its contributors may be used to endorse or promote products
	* derived from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
	* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	* This file incorporates work covered by the following copyright and
	* permission notice:
	* The Synopsys DWC ETHER XGMAC Software Driver and documentation
	* (hereinafter "Software") is an unsupported proprietary work of Synopsys,
	* Inc. unless otherwise expressly agreed to in writing between Synopsys
	* and you.
	*
	* The Software IS NOT an item of Licensed Software or Licensed Product
	* under any End User Software License Agreement or Agreement for Licensed
	* Product with Synopsys or any supplement thereto. Permission is hereby
	* granted, free of charge, to any person obtaining a copy of this software
	* annotated with this license and the Software, to deal in the Software
	* without restriction, including without limitation the rights to use,
	* copy, modify, merge, publish, distribute, sublicense, and/or sell copies
	* of the Software, and to permit persons to whom the Software is furnished
	* to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included
	* in all copies or substantial portions of the Software.
	*
	* THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS"
	* BASIS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
	* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	* PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS
	* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
	* THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include <linux/module.h>
	#include <linux/interrupt.h>
	#include <linux/kmod.h>
	#include <linux/delay.h>
	#include <linux/completion.h>
	#include <linux/mutex.h>

	#include "xgbe.h"
	#include "xgbe-common.h"

	#define XGBE_ABORT_COUNT 500
	#define XGBE_DISABLE_COUNT 1000

	#define XGBE_STD_SPEED 1

	#define XGBE_INTR_RX_FULL BIT(IC_RAW_INTR_STAT_RX_FULL_INDEX)
	#define XGBE_INTR_TX_EMPTY BIT(IC_RAW_INTR_STAT_TX_EMPTY_INDEX)
	#define XGBE_INTR_TX_ABRT BIT(IC_RAW_INTR_STAT_TX_ABRT_INDEX)
	#define XGBE_INTR_STOP_DET BIT(IC_RAW_INTR_STAT_STOP_DET_INDEX)
	#define XGBE_DEFAULT_INT_MASK (XGBE_INTR_RX_FULL \| \
	XGBE_INTR_TX_EMPTY \| \
	XGBE_INTR_TX_ABRT \| \
	XGBE_INTR_STOP_DET)

	#define XGBE_I2C_READ BIT(8)
	#define XGBE_I2C_STOP BIT(9)

	static int xgbe_i2c_abort(struct xgbe_prv_data *pdata)
	{
	unsigned int wait = XGBE_ABORT_COUNT;

	/* Must be enabled to recognize the abort request */
	XI2C_IOWRITE_BITS(pdata, IC_ENABLE, EN, 1);

	/* Issue the abort */
	XI2C_IOWRITE_BITS(pdata, IC_ENABLE, ABORT, 1);

	while (wait--) {
	if (!XI2C_IOREAD_BITS(pdata, IC_ENABLE, ABORT))
	return 0;

	usleep_range(500, 600);
	}

	return -EBUSY;
	}

	static int xgbe_i2c_set_enable(struct xgbe_prv_data *pdata, bool enable)
	{
	unsigned int wait = XGBE_DISABLE_COUNT;
	unsigned int mode = enable ? 1 : 0;

	while (wait--) {
	XI2C_IOWRITE_BITS(pdata, IC_ENABLE, EN, mode);
	if (XI2C_IOREAD_BITS(pdata, IC_ENABLE_STATUS, EN) == mode)
	return 0;

	usleep_range(100, 110);
	}

	return -EBUSY;
	}

	static int xgbe_i2c_disable(struct xgbe_prv_data *pdata)
	{
	unsigned int ret;

	ret = xgbe_i2c_set_enable(pdata, false);
	if (ret) {
	/* Disable failed, try an abort */
	ret = xgbe_i2c_abort(pdata);
	if (ret)
	return ret;

	/* Abort succeeded, try to disable again */
	ret = xgbe_i2c_set_enable(pdata, false);
	}

	return ret;
	}

	static int xgbe_i2c_enable(struct xgbe_prv_data *pdata)
	{
	return xgbe_i2c_set_enable(pdata, true);
	}

	static void xgbe_i2c_clear_all_interrupts(struct xgbe_prv_data *pdata)
	{
	XI2C_IOREAD(pdata, IC_CLR_INTR);
	}

	static void xgbe_i2c_disable_interrupts(struct xgbe_prv_data *pdata)
	{
	XI2C_IOWRITE(pdata, IC_INTR_MASK, 0);
	}

	static void xgbe_i2c_enable_interrupts(struct xgbe_prv_data *pdata)
	{
	XI2C_IOWRITE(pdata, IC_INTR_MASK, XGBE_DEFAULT_INT_MASK);
	}

	static void xgbe_i2c_write(struct xgbe_prv_data *pdata)
	{
	struct xgbe_i2c_op_state *state = &pdata->i2c.op_state;
	unsigned int tx_slots;
	unsigned int cmd;

	/* Configured to never receive Rx overflows, so fill up Tx fifo */
	tx_slots = pdata->i2c.tx_fifo_size - XI2C_IOREAD(pdata, IC_TXFLR);
	while (tx_slots && state->tx_len) {
	if (state->op->cmd == XGBE_I2C_CMD_READ)
	cmd = XGBE_I2C_READ;
	else
	cmd = *state->tx_buf++;

	if (state->tx_len == 1)
	XI2C_SET_BITS(cmd, IC_DATA_CMD, STOP, 1);

	XI2C_IOWRITE(pdata, IC_DATA_CMD, cmd);

	tx_slots--;
	state->tx_len--;
	}

	/* No more Tx operations, so ignore TX_EMPTY and return */
	if (!state->tx_len)
	XI2C_IOWRITE_BITS(pdata, IC_INTR_MASK, TX_EMPTY, 0);
	}

	static void xgbe_i2c_read(struct xgbe_prv_data *pdata)
	{
	struct xgbe_i2c_op_state *state = &pdata->i2c.op_state;
	unsigned int rx_slots;

	/* Anything to be read? */
	if (state->op->cmd != XGBE_I2C_CMD_READ)
	return;

	rx_slots = XI2C_IOREAD(pdata, IC_RXFLR);
	while (rx_slots && state->rx_len) {
	*state->rx_buf++ = XI2C_IOREAD(pdata, IC_DATA_CMD);
	state->rx_len--;
	rx_slots--;
	}
	}

	static void xgbe_i2c_clear_isr_interrupts(struct xgbe_prv_data *pdata,
	unsigned int isr)
	{
	struct xgbe_i2c_op_state *state = &pdata->i2c.op_state;

	if (isr & XGBE_INTR_TX_ABRT) {
	state->tx_abort_source = XI2C_IOREAD(pdata, IC_TX_ABRT_SOURCE);
	XI2C_IOREAD(pdata, IC_CLR_TX_ABRT);
	}

	if (isr & XGBE_INTR_STOP_DET)
	XI2C_IOREAD(pdata, IC_CLR_STOP_DET);
	}

	static void xgbe_i2c_isr_task(unsigned long data)
	{
	struct xgbe_prv_data pdata = (struct xgbe_prv_data )data;
	struct xgbe_i2c_op_state *state = &pdata->i2c.op_state;
	unsigned int isr;

	isr = XI2C_IOREAD(pdata, IC_RAW_INTR_STAT);
	if (!isr)
	goto reissue_check;

	netif_dbg(pdata, intr, pdata->netdev,
	"I2C interrupt received: status=%#010x\n", isr);

	xgbe_i2c_clear_isr_interrupts(pdata, isr);

	if (isr & XGBE_INTR_TX_ABRT) {
	netif_dbg(pdata, link, pdata->netdev,
	"I2C TX_ABRT received (%#010x) for target %#04x\n",
	state->tx_abort_source, state->op->target);

	xgbe_i2c_disable_interrupts(pdata);

	state->ret = -EIO;
	goto out;
	}

	/* Check for data in the Rx fifo */
	xgbe_i2c_read(pdata);

	/* Fill up the Tx fifo next */
	xgbe_i2c_write(pdata);

	out:
	/* Complete on an error or STOP condition */
	if (state->ret \|\| XI2C_GET_BITS(isr, IC_RAW_INTR_STAT, STOP_DET))
	complete(&pdata->i2c_complete);

	reissue_check:
	/* Reissue interrupt if status is not clear */
	if (pdata->vdata->irq_reissue_support)
	XP_IOWRITE(pdata, XP_INT_REISSUE_EN, 1 << 2);
	}

	static irqreturn_t xgbe_i2c_isr(int irq, void *data)
	{
	struct xgbe_prv_data pdata = (struct xgbe_prv_data )data;

	if (pdata->isr_as_tasklet)
	tasklet_schedule(&pdata->tasklet_i2c);
	else
	xgbe_i2c_isr_task((unsigned long)pdata);

	return IRQ_HANDLED;
	}

	static void xgbe_i2c_set_mode(struct xgbe_prv_data *pdata)
	{
	unsigned int reg;

	reg = XI2C_IOREAD(pdata, IC_CON);
	XI2C_SET_BITS(reg, IC_CON, MASTER_MODE, 1);
	XI2C_SET_BITS(reg, IC_CON, SLAVE_DISABLE, 1);
	XI2C_SET_BITS(reg, IC_CON, RESTART_EN, 1);
	XI2C_SET_BITS(reg, IC_CON, SPEED, XGBE_STD_SPEED);
	XI2C_SET_BITS(reg, IC_CON, RX_FIFO_FULL_HOLD, 1);
	XI2C_IOWRITE(pdata, IC_CON, reg);
	}

	static void xgbe_i2c_get_features(struct xgbe_prv_data *pdata)
	{
	struct xgbe_i2c *i2c = &pdata->i2c;
	unsigned int reg;

	reg = XI2C_IOREAD(pdata, IC_COMP_PARAM_1);
	i2c->max_speed_mode = XI2C_GET_BITS(reg, IC_COMP_PARAM_1,
	MAX_SPEED_MODE);
	i2c->rx_fifo_size = XI2C_GET_BITS(reg, IC_COMP_PARAM_1,
	RX_BUFFER_DEPTH);
	i2c->tx_fifo_size = XI2C_GET_BITS(reg, IC_COMP_PARAM_1,
	TX_BUFFER_DEPTH);

	if (netif_msg_probe(pdata))
	dev_dbg(pdata->dev, "I2C features: %s=%u, %s=%u, %s=%u\n",
	"MAX_SPEED_MODE", i2c->max_speed_mode,
	"RX_BUFFER_DEPTH", i2c->rx_fifo_size,
	"TX_BUFFER_DEPTH", i2c->tx_fifo_size);
	}

	static void xgbe_i2c_set_target(struct xgbe_prv_data *pdata, unsigned int addr)
	{
	XI2C_IOWRITE(pdata, IC_TAR, addr);
	}

	static irqreturn_t xgbe_i2c_combined_isr(struct xgbe_prv_data *pdata)
	{
	xgbe_i2c_isr_task((unsigned long)pdata);

	return IRQ_HANDLED;
	}

	static int xgbe_i2c_xfer(struct xgbe_prv_data pdata, struct xgbe_i2c_op op)
	{
	struct xgbe_i2c_op_state *state = &pdata->i2c.op_state;
	int ret;

	mutex_lock(&pdata->i2c_mutex);

	reinit_completion(&pdata->i2c_complete);

	ret = xgbe_i2c_disable(pdata);
	if (ret) {
	netdev_err(pdata->netdev, "failed to disable i2c master\n");
	goto unlock;
	}

	xgbe_i2c_set_target(pdata, op->target);

	memset(state, 0, sizeof(*state));
	state->op = op;
	state->tx_len = op->len;
	state->tx_buf = op->buf;
	state->rx_len = op->len;
	state->rx_buf = op->buf;

	xgbe_i2c_clear_all_interrupts(pdata);
	ret = xgbe_i2c_enable(pdata);
	if (ret) {
	netdev_err(pdata->netdev, "failed to enable i2c master\n");
	goto unlock;
	}

	/* Enabling the interrupts will cause the TX FIFO empty interrupt to
	* fire and begin to process the command via the ISR.
	*/
	xgbe_i2c_enable_interrupts(pdata);

	if (!wait_for_completion_timeout(&pdata->i2c_complete, HZ)) {
	netdev_err(pdata->netdev, "i2c operation timed out\n");
	ret = -ETIMEDOUT;
	goto disable;
	}

	ret = state->ret;
	if (ret) {
	if (state->tx_abort_source & IC_TX_ABRT_7B_ADDR_NOACK)
	ret = -ENOTCONN;
	else if (state->tx_abort_source & IC_TX_ABRT_ARB_LOST)
	ret = -EAGAIN;
	}

	disable:
	xgbe_i2c_disable_interrupts(pdata);
	xgbe_i2c_disable(pdata);

	unlock:
	mutex_unlock(&pdata->i2c_mutex);

	return ret;
	}

	static void xgbe_i2c_stop(struct xgbe_prv_data *pdata)
	{
	if (!pdata->i2c.started)
	return;

	netif_dbg(pdata, link, pdata->netdev, "stopping I2C\n");

	pdata->i2c.started = 0;

	xgbe_i2c_disable_interrupts(pdata);
	xgbe_i2c_disable(pdata);
	xgbe_i2c_clear_all_interrupts(pdata);

	if (pdata->dev_irq != pdata->i2c_irq)
	devm_free_irq(pdata->dev, pdata->i2c_irq, pdata);
	}

	static int xgbe_i2c_start(struct xgbe_prv_data *pdata)
	{
	int ret;

	if (pdata->i2c.started)
	return 0;

	netif_dbg(pdata, link, pdata->netdev, "starting I2C\n");

	/* If we have a separate I2C irq, enable it */
	if (pdata->dev_irq != pdata->i2c_irq) {
	tasklet_init(&pdata->tasklet_i2c, xgbe_i2c_isr_task,
	(unsigned long)pdata);

	ret = devm_request_irq(pdata->dev, pdata->i2c_irq,
	xgbe_i2c_isr, 0, pdata->i2c_name,
	pdata);
	if (ret) {
	netdev_err(pdata->netdev, "i2c irq request failed\n");
	return ret;
	}
	}

	pdata->i2c.started = 1;

	return 0;
	}

	static int xgbe_i2c_init(struct xgbe_prv_data *pdata)
	{
	int ret;

	xgbe_i2c_disable_interrupts(pdata);

	ret = xgbe_i2c_disable(pdata);
	if (ret) {
	dev_err(pdata->dev, "failed to disable i2c master\n");
	return ret;
	}

	xgbe_i2c_get_features(pdata);

	xgbe_i2c_set_mode(pdata);

	xgbe_i2c_clear_all_interrupts(pdata);

	return 0;
	}

	void xgbe_init_function_ptrs_i2c(struct xgbe_i2c_if *i2c_if)
	{
	i2c_if->i2c_init = xgbe_i2c_init;

	i2c_if->i2c_start = xgbe_i2c_start;
	i2c_if->i2c_stop = xgbe_i2c_stop;

	i2c_if->i2c_xfer = xgbe_i2c_xfer;

	i2c_if->i2c_isr = xgbe_i2c_combined_isr;
	}