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: Tom Lendacky <thomas.lenda...@amd.com>
---
 drivers/net/ethernet/amd/xgbe/Makefile       |    2 
 drivers/net/ethernet/amd/xgbe/xgbe-common.h  |   92 +++++
 drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c |   76 ++++
 drivers/net/ethernet/amd/xgbe/xgbe-drv.c     |    4 
 drivers/net/ethernet/amd/xgbe/xgbe-i2c.c     |  492 ++++++++++++++++++++++++++
 drivers/net/ethernet/amd/xgbe/xgbe-main.c    |    7 
 drivers/net/ethernet/amd/xgbe/xgbe-pci.c     |    2 
 drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c  |   15 +
 drivers/net/ethernet/amd/xgbe/xgbe.h         |   64 +++
 9 files changed, 753 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/ethernet/amd/xgbe/xgbe-i2c.c

diff --git a/drivers/net/ethernet/amd/xgbe/Makefile 
b/drivers/net/ethernet/amd/xgbe/Makefile
index d1ce1c1..0dea8f5 100644
--- a/drivers/net/ethernet/amd/xgbe/Makefile
+++ b/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
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-common.h 
b/drivers/net/ethernet/amd/xgbe/xgbe-common.h
index f7527cd..3b81b83 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-common.h
+++ b/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
@@ -1470,6 +1529,39 @@
 } 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
  * operations, everything works on mask values.
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c 
b/drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c
index 951b5ab..0c0140d 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-debugfs.c
@@ -376,6 +376,66 @@ static ssize_t xprop_reg_value_write(struct file *filp,
        .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);
 }
 
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c 
b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index fc3b703..7af358f 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/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;
 }
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-i2c.c 
b/drivers/net/ethernet/amd/xgbe/xgbe-i2c.c
new file mode 100644
index 0000000..0c7088a
--- /dev/null
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-i2c.c
@@ -0,0 +1,492 @@
+/*
+ * 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;
+}
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-main.c 
b/drivers/net/ethernet/amd/xgbe/xgbe-main.c
index b16b7b6..385b7f6 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-main.c
+++ b/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));
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-pci.c 
b/drivers/net/ethernet/amd/xgbe/xgbe-pci.c
index 798a65e..e76b7f6 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-pci.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-pci.c
@@ -483,6 +483,7 @@ static int xgbe_pci_resume(struct pci_dev *pdev)
        .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 int xgbe_pci_resume(struct pci_dev *pdev)
        .rx_max_fifo_size               = 65536,
        .tx_tstamp_workaround           = 1,
        .ecc_support                    = 1,
+       .i2c_support                    = 1,
 };
 
 static const struct pci_device_id xgbe_pci_table[] = {
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c 
b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
index 7ae0abc..4bfe5c2 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
+++ b/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;
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe.h 
b/drivers/net/ethernet/amd/xgbe/xgbe.h
index 2f0b0b4..586154f 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe.h
+++ b/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 @@ static inline void xgbe_pci_exit(void) { }
 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);
 

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