amd-xgbe: Add I2C support for sideband communication

Add support to initialize and use the I2C controller within the hardware
in order to perform sideband communication, e.g. determine the SFP media
type that is installed.
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/amd/xgbe/Makefile

@@ -3,7 +3,7 @@ obj-$(CONFIG_AMD_XGBE) += amd-xgbe.o
 amd-xgbe-objs := xgbe-main.o xgbe-drv.o xgbe-dev.o \
 		 xgbe-desc.o xgbe-ethtool.o xgbe-mdio.o \
 		 xgbe-ptp.o \
-		 xgbe-phy-v1.o xgbe-phy-v2.o \
+		 xgbe-i2c.o xgbe-phy-v1.o xgbe-phy-v2.o \
 		 xgbe-platform.o
 
 amd-xgbe-$(CONFIG_PCI) += xgbe-pci.o

drivers/net/ethernet/amd/xgbe/xgbe-common.h

@@ -1000,6 +1000,65 @@
 #define XP_PROP_2_TX_FIFO_SIZE_INDEX		0
 #define XP_PROP_2_TX_FIFO_SIZE_WIDTH		16
 
+/* I2C Control register offsets */
+#define IC_CON					0x0000
+#define IC_TAR					0x0004
+#define IC_DATA_CMD				0x0010
+#define IC_INTR_STAT				0x002c
+#define IC_INTR_MASK				0x0030
+#define IC_RAW_INTR_STAT			0x0034
+#define IC_CLR_INTR				0x0040
+#define IC_CLR_TX_ABRT				0x0054
+#define IC_CLR_STOP_DET				0x0060
+#define IC_ENABLE				0x006c
+#define IC_TXFLR				0x0074
+#define IC_RXFLR				0x0078
+#define IC_TX_ABRT_SOURCE			0x0080
+#define IC_ENABLE_STATUS			0x009c
+#define IC_COMP_PARAM_1				0x00f4
+
+/* I2C Control register entry bit positions and sizes */
+#define IC_COMP_PARAM_1_MAX_SPEED_MODE_INDEX	2
+#define IC_COMP_PARAM_1_MAX_SPEED_MODE_WIDTH	2
+#define IC_COMP_PARAM_1_RX_BUFFER_DEPTH_INDEX	8
+#define IC_COMP_PARAM_1_RX_BUFFER_DEPTH_WIDTH	8
+#define IC_COMP_PARAM_1_TX_BUFFER_DEPTH_INDEX	16
+#define IC_COMP_PARAM_1_TX_BUFFER_DEPTH_WIDTH	8
+#define IC_CON_MASTER_MODE_INDEX		0
+#define IC_CON_MASTER_MODE_WIDTH		1
+#define IC_CON_RESTART_EN_INDEX			5
+#define IC_CON_RESTART_EN_WIDTH			1
+#define IC_CON_RX_FIFO_FULL_HOLD_INDEX		9
+#define IC_CON_RX_FIFO_FULL_HOLD_WIDTH		1
+#define IC_CON_SLAVE_DISABLE_INDEX		6
+#define IC_CON_SLAVE_DISABLE_WIDTH		1
+#define IC_CON_SPEED_INDEX			1
+#define IC_CON_SPEED_WIDTH			2
+#define IC_DATA_CMD_CMD_INDEX			8
+#define IC_DATA_CMD_CMD_WIDTH			1
+#define IC_DATA_CMD_STOP_INDEX			9
+#define IC_DATA_CMD_STOP_WIDTH			1
+#define IC_ENABLE_ABORT_INDEX			1
+#define IC_ENABLE_ABORT_WIDTH			1
+#define IC_ENABLE_EN_INDEX			0
+#define IC_ENABLE_EN_WIDTH			1
+#define IC_ENABLE_STATUS_EN_INDEX		0
+#define IC_ENABLE_STATUS_EN_WIDTH		1
+#define IC_INTR_MASK_TX_EMPTY_INDEX		4
+#define IC_INTR_MASK_TX_EMPTY_WIDTH		1
+#define IC_RAW_INTR_STAT_RX_FULL_INDEX		2
+#define IC_RAW_INTR_STAT_RX_FULL_WIDTH		1
+#define IC_RAW_INTR_STAT_STOP_DET_INDEX		9
+#define IC_RAW_INTR_STAT_STOP_DET_WIDTH		1
+#define IC_RAW_INTR_STAT_TX_ABRT_INDEX		6
+#define IC_RAW_INTR_STAT_TX_ABRT_WIDTH		1
+#define IC_RAW_INTR_STAT_TX_EMPTY_INDEX		4
+#define IC_RAW_INTR_STAT_TX_EMPTY_WIDTH		1
+
+/* I2C Control register value */
+#define IC_TX_ABRT_7B_ADDR_NOACK		0x0001
+#define IC_TX_ABRT_ARB_LOST			0x1000
+
 /* Descriptor/Packet entry bit positions and sizes */
 #define RX_PACKET_ERRORS_CRC_INDEX		2
 #define RX_PACKET_ERRORS_CRC_WIDTH		1
@@ -1469,6 +1528,39 @@ do {									\
 	XP_IOWRITE((_pdata), (_reg), reg_val);				\
 } while (0)
 
+/* Macros for building, reading or writing register values or bits
+ * within the register values of I2C Control registers.
+ */
+#define XI2C_GET_BITS(_var, _prefix, _field)				\
+	GET_BITS((_var),						\
+		 _prefix##_##_field##_INDEX,				\
+		 _prefix##_##_field##_WIDTH)
+
+#define XI2C_SET_BITS(_var, _prefix, _field, _val)			\
+	SET_BITS((_var),						\
+		 _prefix##_##_field##_INDEX,				\
+		 _prefix##_##_field##_WIDTH, (_val))
+
+#define XI2C_IOREAD(_pdata, _reg)					\
+	ioread32((_pdata)->xi2c_regs + (_reg))
+
+#define XI2C_IOREAD_BITS(_pdata, _reg, _field)				\
+	GET_BITS(XI2C_IOREAD((_pdata), (_reg)),				\
+		 _reg##_##_field##_INDEX,				\
+		 _reg##_##_field##_WIDTH)
+
+#define XI2C_IOWRITE(_pdata, _reg, _val)				\
+	iowrite32((_val), (_pdata)->xi2c_regs + (_reg))
+
+#define XI2C_IOWRITE_BITS(_pdata, _reg, _field, _val)			\
+do {									\
+	u32 reg_val = XI2C_IOREAD((_pdata), (_reg));			\
+	SET_BITS(reg_val,						\
+		 _reg##_##_field##_INDEX,				\
+		 _reg##_##_field##_WIDTH, (_val));			\
+	XI2C_IOWRITE((_pdata), (_reg), reg_val);			\
+} while (0)
+
 /* Macros for building, reading or writing register values or bits
  * using MDIO.  Different from above because of the use of standardized
  * Linux include values.  No shifting is performed with the bit

drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c

@@ -376,6 +376,66 @@ static const struct file_operations xprop_reg_value_fops = {
 	.write = xprop_reg_value_write,
 };
 
+static ssize_t xi2c_reg_addr_read(struct file *filp, char __user *buffer,
+				  size_t count, loff_t *ppos)
+{
+	struct xgbe_prv_data *pdata = filp->private_data;
+
+	return xgbe_common_read(buffer, count, ppos, pdata->debugfs_xi2c_reg);
+}
+
+static ssize_t xi2c_reg_addr_write(struct file *filp,
+				   const char __user *buffer,
+				   size_t count, loff_t *ppos)
+{
+	struct xgbe_prv_data *pdata = filp->private_data;
+
+	return xgbe_common_write(buffer, count, ppos,
+				 &pdata->debugfs_xi2c_reg);
+}
+
+static ssize_t xi2c_reg_value_read(struct file *filp, char __user *buffer,
+				   size_t count, loff_t *ppos)
+{
+	struct xgbe_prv_data *pdata = filp->private_data;
+	unsigned int value;
+
+	value = XI2C_IOREAD(pdata, pdata->debugfs_xi2c_reg);
+
+	return xgbe_common_read(buffer, count, ppos, value);
+}
+
+static ssize_t xi2c_reg_value_write(struct file *filp,
+				    const char __user *buffer,
+				    size_t count, loff_t *ppos)
+{
+	struct xgbe_prv_data *pdata = filp->private_data;
+	unsigned int value;
+	ssize_t len;
+
+	len = xgbe_common_write(buffer, count, ppos, &value);
+	if (len < 0)
+		return len;
+
+	XI2C_IOWRITE(pdata, pdata->debugfs_xi2c_reg, value);
+
+	return len;
+}
+
+static const struct file_operations xi2c_reg_addr_fops = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read =  xi2c_reg_addr_read,
+	.write = xi2c_reg_addr_write,
+};
+
+static const struct file_operations xi2c_reg_value_fops = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read =  xi2c_reg_value_read,
+	.write = xi2c_reg_value_write,
+};
+
 void xgbe_debugfs_init(struct xgbe_prv_data *pdata)
 {
 	struct dentry *pfile;
@@ -443,6 +503,22 @@ void xgbe_debugfs_init(struct xgbe_prv_data *pdata)
 				   "debugfs_create_file failed\n");
 	}
 
+	if (pdata->xi2c_regs) {
+		pfile = debugfs_create_file("xi2c_register", 0600,
+					    pdata->xgbe_debugfs, pdata,
+					    &xi2c_reg_addr_fops);
+		if (!pfile)
+			netdev_err(pdata->netdev,
+				   "debugfs_create_file failed\n");
+
+		pfile = debugfs_create_file("xi2c_register_value", 0600,
+					    pdata->xgbe_debugfs, pdata,
+					    &xi2c_reg_value_fops);
+		if (!pfile)
+			netdev_err(pdata->netdev,
+				   "debugfs_create_file failed\n");
+	}
+
 	kfree(buf);
 }
 

drivers/net/ethernet/amd/xgbe/xgbe-drv.c

@@ -530,6 +530,10 @@ static irqreturn_t xgbe_isr(int irq, void *data)
 	if (pdata->vdata->ecc_support && (pdata->dev_irq == pdata->ecc_irq))
 		xgbe_ecc_isr(irq, pdata);
 
+	/* If there is not a separate I2C irq, handle it here */
+	if (pdata->vdata->i2c_support && (pdata->dev_irq == pdata->i2c_irq))
+		pdata->i2c_if.i2c_isr(irq, pdata);
+
 isr_done:
 	return IRQ_HANDLED;
 }

drivers/net/ethernet/amd/xgbe/xgbe-i2c.c

+/*
+ * 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/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 irqreturn_t xgbe_i2c_isr(int irq, void *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);
+	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);
+
+	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(int irq, struct xgbe_prv_data *pdata)
+{
+	if (!XI2C_IOREAD(pdata, IC_RAW_INTR_STAT))
+		return IRQ_HANDLED;
+
+	return xgbe_i2c_isr(irq, pdata);
+}
+
+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) {
+		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;
+}

drivers/net/ethernet/amd/xgbe/xgbe-main.c

@@ -161,6 +161,7 @@ static void xgbe_init_all_fptrs(struct xgbe_prv_data *pdata)
 {
 	xgbe_init_function_ptrs_dev(&pdata->hw_if);
 	xgbe_init_function_ptrs_phy(&pdata->phy_if);
+	xgbe_init_function_ptrs_i2c(&pdata->i2c_if);
 	xgbe_init_function_ptrs_desc(&pdata->desc_if);
 
 	pdata->vdata->init_function_ptrs_phy_impl(&pdata->phy_if);
@@ -186,6 +187,8 @@ struct xgbe_prv_data *xgbe_alloc_pdata(struct device *dev)
 	spin_lock_init(&pdata->xpcs_lock);
 	mutex_init(&pdata->rss_mutex);
 	spin_lock_init(&pdata->tstamp_lock);
+	mutex_init(&pdata->i2c_mutex);
+	init_completion(&pdata->i2c_complete);
 
 	pdata->msg_enable = netif_msg_init(debug, default_msg_level);
 
@@ -397,6 +400,10 @@ int xgbe_config_netdev(struct xgbe_prv_data *pdata)
 	snprintf(pdata->ecc_name, sizeof(pdata->ecc_name) - 1, "%s-ecc",
 		 netdev_name(netdev));
 
+	/* Create the I2C name based on netdev name */
+	snprintf(pdata->i2c_name, sizeof(pdata->i2c_name) - 1, "%s-i2c",
+		 netdev_name(netdev));
+
 	/* Create workqueues */
 	pdata->dev_workqueue =
 		create_singlethread_workqueue(netdev_name(netdev));

drivers/net/ethernet/amd/xgbe/xgbe-pci.c

@@ -483,6 +483,7 @@ static const struct xgbe_version_data xgbe_v2a = {
 	.rx_max_fifo_size		= 229376,
 	.tx_tstamp_workaround		= 1,
 	.ecc_support			= 1,
+	.i2c_support			= 1,
 };
 
 static const struct xgbe_version_data xgbe_v2b = {
@@ -493,6 +494,7 @@ static const struct xgbe_version_data xgbe_v2b = {
 	.rx_max_fifo_size		= 65536,
 	.tx_tstamp_workaround		= 1,
 	.ecc_support			= 1,
+	.i2c_support			= 1,
 };
 
 static const struct pci_device_id xgbe_pci_table[] = {

drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c

@@ -710,11 +710,20 @@ static void xgbe_phy_stop(struct xgbe_prv_data *pdata)
 {
 	/* Power off the PHY */
 	xgbe_phy_power_off(pdata);
+
+	/* Stop the I2C controller */
+	pdata->i2c_if.i2c_stop(pdata);
 }
 
 static int xgbe_phy_start(struct xgbe_prv_data *pdata)
 {
 	struct xgbe_phy_data *phy_data = pdata->phy_data;
+	int ret;
+
+	/* Start the I2C controller */
+	ret = pdata->i2c_if.i2c_start(pdata);
+	if (ret)
+		return ret;
 
 	/* Start in highest supported mode */
 	xgbe_phy_set_mode(pdata, phy_data->start_mode);
@@ -744,6 +753,7 @@ static int xgbe_phy_init(struct xgbe_prv_data *pdata)
 {
 	struct xgbe_phy_data *phy_data;
 	unsigned int reg;
+	int ret;
 
 	/* Check if enabled */
 	if (!xgbe_phy_port_enabled(pdata)) {
@@ -751,6 +761,11 @@ static int xgbe_phy_init(struct xgbe_prv_data *pdata)
 		return -ENODEV;
 	}
 
+	/* Initialize the I2C controller */
+	ret = pdata->i2c_if.i2c_init(pdata);
+	if (ret)
+		return ret;
+
 	phy_data = devm_kzalloc(pdata->dev, sizeof(*phy_data), GFP_KERNEL);
 	if (!phy_data)
 		return -ENOMEM;

drivers/net/ethernet/amd/xgbe/xgbe.h

@@ -127,6 +127,7 @@
 #include <linux/timecounter.h>
 #include <linux/net_tstamp.h>
 #include <net/dcbnl.h>
+#include <linux/completion.h>
 
 #define XGBE_DRV_NAME		"amd-xgbe"
 #define XGBE_DRV_VERSION	"1.0.3"
@@ -555,6 +556,43 @@ struct xgbe_phy {
 	int rx_pause;
 };
 
+enum xgbe_i2c_cmd {
+	XGBE_I2C_CMD_READ = 0,
+	XGBE_I2C_CMD_WRITE,
+};
+
+struct xgbe_i2c_op {
+	enum xgbe_i2c_cmd cmd;
+
+	unsigned int target;
+
+	void *buf;
+	unsigned int len;
+};
+
+struct xgbe_i2c_op_state {
+	struct xgbe_i2c_op *op;
+
+	unsigned int tx_len;
+	unsigned char *tx_buf;
+
+	unsigned int rx_len;
+	unsigned char *rx_buf;
+
+	unsigned int tx_abort_source;
+
+	int ret;
+};
+
+struct xgbe_i2c {
+	unsigned int started;
+	unsigned int max_speed_mode;
+	unsigned int rx_fifo_size;
+	unsigned int tx_fifo_size;
+
+	struct xgbe_i2c_op_state op_state;
+};
+
 struct xgbe_mmc_stats {
 	/* Tx Stats */
 	u64 txoctetcount_gb;
@@ -777,6 +815,21 @@ struct xgbe_phy_if {
 	struct xgbe_phy_impl_if phy_impl;
 };
 
+struct xgbe_i2c_if {
+	/* For initial I2C setup */
+	int (*i2c_init)(struct xgbe_prv_data *);
+
+	/* For I2C support when setting device up/down */
+	int (*i2c_start)(struct xgbe_prv_data *);
+	void (*i2c_stop)(struct xgbe_prv_data *);
+
+	/* For performing I2C operations */
+	int (*i2c_xfer)(struct xgbe_prv_data *, struct xgbe_i2c_op *);
+
+	/* For single interrupt support */
+	irqreturn_t (*i2c_isr)(int, struct xgbe_prv_data *);
+};
+
 struct xgbe_desc_if {
 	int (*alloc_ring_resources)(struct xgbe_prv_data *);
 	void (*free_ring_resources)(struct xgbe_prv_data *);
@@ -842,6 +895,7 @@ struct xgbe_version_data {
 	unsigned int rx_max_fifo_size;
 	unsigned int tx_tstamp_workaround;
 	unsigned int ecc_support;
+	unsigned int i2c_support;
 };
 
 struct xgbe_prv_data {
@@ -915,6 +969,7 @@ struct xgbe_prv_data {
 	struct xgbe_hw_if hw_if;
 	struct xgbe_phy_if phy_if;
 	struct xgbe_desc_if desc_if;
+	struct xgbe_i2c_if i2c_if;
 
 	/* AXI DMA settings */
 	unsigned int coherent;
@@ -1065,6 +1120,12 @@ struct xgbe_prv_data {
 	unsigned long an_start;
 	enum xgbe_an_mode an_mode;
 
+	/* I2C support */
+	struct xgbe_i2c i2c;
+	struct mutex i2c_mutex;
+	struct completion i2c_complete;
+	char i2c_name[IFNAMSIZ + 32];
+
 	unsigned int lpm_ctrl;		/* CTRL1 for resume */
 
 #ifdef CONFIG_DEBUG_FS
@@ -1076,6 +1137,8 @@ struct xgbe_prv_data {
 	unsigned int debugfs_xpcs_reg;
 
 	unsigned int debugfs_xprop_reg;
+
+	unsigned int debugfs_xi2c_reg;
 #endif
 };
 
@@ -1101,6 +1164,7 @@ void xgbe_init_function_ptrs_phy(struct xgbe_phy_if *);
 void xgbe_init_function_ptrs_phy_v1(struct xgbe_phy_if *);
 void xgbe_init_function_ptrs_phy_v2(struct xgbe_phy_if *);
 void xgbe_init_function_ptrs_desc(struct xgbe_desc_if *);
+void xgbe_init_function_ptrs_i2c(struct xgbe_i2c_if *);
 const struct net_device_ops *xgbe_get_netdev_ops(void);
 const struct ethtool_ops *xgbe_get_ethtool_ops(void);