[RESEND PATCH] i2c: Adding support for Intel iSMT SMBus 2.0 host controller

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The iSMT (Intel SMBus Message Transport) supports multi-master I2C/SMBus,
as well as IPMI.  It's operation is DMA-based and utilizes descriptors to
initiate transactions on the bus.

The iSMT hardware can act as both a master and a target, although this
driver only supports being a master.

Signed-off-by: Bill Brown <bill.e.brown@xxxxxxxxx>
---
 drivers/i2c/busses/Kconfig    |   10 +
 drivers/i2c/busses/Makefile   |    1 +
 drivers/i2c/busses/i2c-ismt.c |  862 +++++++++++++++++++++++++++++++++++++++++
 drivers/i2c/busses/i2c-ismt.h |  111 ++++++
 4 files changed, 984 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/busses/i2c-ismt.c
 create mode 100644 drivers/i2c/busses/i2c-ismt.h

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index d2c5095..2b5ffa3 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -119,6 +119,16 @@ config I2C_ISCH
 	  This driver can also be built as a module. If so, the module
 	  will be called i2c-isch.
 
+config I2C_ISMT
+	tristate "Intel iSMT SMBus Controller"
+	depends on PCI
+	help
+	  If you say yes to this option, support will be included for the Intel
+	  iSMT SMBus host controller interface.
+
+	  This driver can also be built as a module.  If so, the module will be
+	  called i2c-ismt.
+
 config I2C_PIIX4
 	tristate "Intel PIIX4 and compatible (ATI/AMD/Serverworks/Broadcom/SMSC)"
 	depends on PCI
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 569567b..8a05c80 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_I2C_SIS630)	+= i2c-sis630.o
 obj-$(CONFIG_I2C_SIS96X)	+= i2c-sis96x.o
 obj-$(CONFIG_I2C_VIA)		+= i2c-via.o
 obj-$(CONFIG_I2C_VIAPRO)	+= i2c-viapro.o
+obj-$(CONFIG_I2C_ISMT)		+= i2c-ismt.o
 
 # Mac SMBus host controller drivers
 obj-$(CONFIG_I2C_HYDRA)		+= i2c-hydra.o
diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c
new file mode 100644
index 0000000..dd107dd
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ismt.c
@@ -0,0 +1,862 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ * The full GNU General Public License is included in this distribution
+ * in the file called LICENSE.GPL.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ * 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 Intel Corporation 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 THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS 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.
+ */
+
+/*
+  Supports the SMBus Message Transport (SMT) on the following Intel SOCs:
+  BWD
+  CTN
+
+  Features supported by this driver:
+  Software PEC                     no
+  Hardware PEC                     yes
+  Block buffer                     yes
+  Block process call transaction   no
+  Slave mode                       no
+*/
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/kernel.h>
+#include <linux/stddef.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+#include "i2c-ismt.h"
+
+/**
+ * DEFINE_PCI_DEVICE_TABLE - PCI device IDs supported by this driver
+ */
+static const DEFINE_PCI_DEVICE_TABLE(ismt_ids) = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_BWD_SMBUS_SMT0) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_BWD_SMBUS_SMT1) },
+	{ 0, }
+};
+
+MODULE_DEVICE_TABLE(pci, ismt_ids);
+
+/* Master Descriptor control bits */
+static unsigned int stop_on_error = 1;
+module_param(stop_on_error, uint, S_IRUGO);
+MODULE_PARM_DESC(stop_on_error, "Stop on Error");
+
+static unsigned int fair = 1;
+module_param(fair, uint, S_IRUGO);
+MODULE_PARM_DESC(fair, "Enable fairness on the SMBus");
+
+#ifdef DEBUG
+/**
+ * ismt_desc_dump() - dump the contents of a descriptor for debug purposes
+ * @adap: the I2C host adapter
+ */
+static void ismt_desc_dump(struct i2c_adapter *adap)
+{
+	struct ismt_priv *priv = i2c_get_adapdata(adap);
+	struct device *dev = &priv->pci_dev->dev;
+	struct ismt_desc *desc = &priv->hw[priv->head];
+
+	dev_dbg(dev, "Dump of the descriptor struct:  0x%X\n", priv->head);
+	dev_dbg(dev, "\ttgtaddr_rw=0x%02X\n", desc->tgtaddr_rw);
+	dev_dbg(dev, "\twr_len_cmd=0x%02X\n", desc->wr_len_cmd);
+	dev_dbg(dev, "\trd_len=    0x%02X\n", desc->rd_len);
+	dev_dbg(dev, "\tcontrol=   0x%02X\n", desc->control);
+	dev_dbg(dev, "\tstatus=    0x%02X\n", desc->status);
+	dev_dbg(dev, "\tretry=     0x%02X\n", desc->retry);
+	dev_dbg(dev, "\trxbytes=   0x%02X\n", desc->rxbytes);
+	dev_dbg(dev, "\ttxbytes=   0x%02X\n", desc->txbytes);
+	dev_dbg(dev, "\tdptr_low=  0x%08X\n", desc->dptr_low);
+	dev_dbg(dev, "\tdptr_high= 0x%08X\n", desc->dptr_high);
+
+	return;
+}
+
+/**
+ * ismt_gen_reg_dump() - dump the iSMT General Registers
+ * @adap: the I2C host adapter
+ */
+static void ismt_gen_reg_dump(struct i2c_adapter *adap)
+{
+	struct ismt_priv *priv = i2c_get_adapdata(adap);
+	struct device *dev = &priv->pci_dev->dev;
+
+	dev_dbg(dev, "Dump of the iSMT General Registers\n");
+	dev_dbg(dev, "  GCTRL.... : (0x%p)=0x%X\n",
+		priv->smba + ISMT_GR_GCTRL,
+		readl(priv->smba + ISMT_GR_GCTRL));
+	dev_dbg(dev, "  SMTICL... : (0x%p)=0x%016lX\n",
+		priv->smba + ISMT_GR_SMTICL,
+		readq(priv->smba + ISMT_GR_SMTICL));
+	dev_dbg(dev, "  ERRINTMSK : (0x%p)=0x%X\n",
+		priv->smba + ISMT_GR_ERRINTMSK,
+		readl(priv->smba + ISMT_GR_ERRINTMSK));
+	dev_dbg(dev, "  ERRAERMSK : (0x%p)=0x%X\n",
+		priv->smba + ISMT_GR_ERRAERMSK,
+		readl(priv->smba + ISMT_GR_ERRAERMSK));
+	dev_dbg(dev, "  ERRSTS... : (0x%p)=0x%X\n",
+		priv->smba + ISMT_GR_ERRSTS,
+		readl(priv->smba + ISMT_GR_ERRSTS));
+	dev_dbg(dev, "  ERRINFO.. : (0x%p)=0x%X\n",
+		priv->smba + ISMT_GR_ERRINFO,
+		readl(priv->smba + ISMT_GR_ERRINFO));
+
+	return;
+}
+
+/**
+ * ismt_mstr_reg_dump() - dump the iSMT Master Registers
+ * @adap: the I2C host adapter
+ */
+static void ismt_mstr_reg_dump(struct i2c_adapter *adap)
+{
+	struct ismt_priv *priv = i2c_get_adapdata(adap);
+	struct device *dev = &priv->pci_dev->dev;
+
+	dev_dbg(dev, "Dump of the iSMT Master Registers\n");
+	dev_dbg(dev, "  MDBA..... : (0x%p)=0x%016lX\n",
+		priv->smba + ISMT_MSTR_MDBA,
+		readq(priv->smba + ISMT_MSTR_MDBA));
+	dev_dbg(dev, "  MCTRL.... : (0x%p)=0x%X\n",
+		priv->smba + ISMT_MSTR_MCTRL,
+		readl(priv->smba + ISMT_MSTR_MCTRL));
+	dev_dbg(dev, "  MSTS..... : (0x%p)=0x%X\n",
+		priv->smba + ISMT_MSTR_MSTS,
+		readl(priv->smba + ISMT_MSTR_MSTS));
+	dev_dbg(dev, "  MDS...... : (0x%p)=0x%X\n",
+		priv->smba + ISMT_MSTR_MDS,
+		readl(priv->smba + ISMT_MSTR_MDS));
+	dev_dbg(dev, "  RPOLICY.. : (0x%p)=0x%X\n",
+		priv->smba + ISMT_MSTR_RPOLICY,
+		readl(priv->smba + ISMT_MSTR_RPOLICY));
+	dev_dbg(dev, "  SPGT..... : (0x%p)=0x%X\n",
+		priv->smba + ISMT_SPGT,
+		readl(priv->smba + ISMT_SPGT));
+
+	return;
+}
+
+#else
+static void ismt_desc_dump(struct i2c_adapter *adap) {}
+static void ismt_gen_reg_dump(struct i2c_adapter *adap) {}
+static void ismt_mstr_reg_dump(struct i2c_adapter *adap) {}
+#endif
+
+/**
+ * ismt_insert_cmd() -  stuff a command into the head of the data buffer
+ * @data: data buffer
+ * @command: command to insert
+ */
+static void ismt_insert_cmd(union i2c_smbus_data *data, u8 command)
+{
+	memmove(&data->block[1], &data->block[0], I2C_SMBUS_BLOCK_MAX);
+	data->block[0] = command;
+
+	return;
+}
+
+/**
+ * ismt_submit_desc() - add a descriptor to the ring
+ * @adap: the i2c host adapter
+ */
+static void ismt_submit_desc(struct i2c_adapter *adap)
+{
+	int fmhp;
+	int val;
+	struct ismt_priv *priv = i2c_get_adapdata(adap);
+
+	ismt_desc_dump(adap);
+	ismt_gen_reg_dump(adap);
+	ismt_mstr_reg_dump(adap);
+
+	/* Set the FMHP (Firmware Master Head Pointer)*/
+	fmhp = ((priv->head + 1) % ISMT_DESC_ENTRIES) << 16;
+	val = readl(priv->smba + ISMT_MSTR_MCTRL);
+	writel((val & ~(ISMT_MCTRL_FMHP)) | fmhp,
+		(priv->smba + ISMT_MSTR_MCTRL));
+
+	/* Set the start bit */
+	val = readl(priv->smba + ISMT_MSTR_MCTRL);
+	writel((val | ISMT_MCTRL_SS),
+	       (priv->smba + ISMT_MSTR_MCTRL));
+
+	return;
+}
+
+/**
+ * ismt_process_desc() - handle the completion of the descriptor
+ * @adap: the i2c host adapter
+ */
+static int ismt_process_desc(struct i2c_adapter *adap)
+{
+	int ret = 0;
+
+	struct ismt_desc *desc;
+	struct ismt_priv *priv = i2c_get_adapdata(adap);
+
+	desc = &priv->hw[priv->head];
+
+	if (desc->status & ISMT_DESC_SCS)
+		return 0;
+
+	if ((desc->status & ISMT_DESC_NAK) || (desc->status & ISMT_DESC_CRC)) {
+		ret = -ENXIO;
+		goto done;
+	}
+
+	if (desc->status & ISMT_DESC_COL) {
+		ret = -EAGAIN;
+		goto done;
+	}
+
+done:
+	return ret;
+}
+
+/**
+ * ismt_access() - process an SMBus command
+ * @adap: the i2c host adapter
+ * @addr: address of the i2c/SMBus target
+ * @flags: command options
+ * @read_write: read from or write to device
+ * @command: the i2c/SMBus command to issue
+ * @size: SMBus transaction type
+ * @data: read/write data buffer
+ */
+static int ismt_access(struct i2c_adapter *adap, u16 addr,
+		       unsigned short flags, char read_write, u8 command,
+		       int size, union i2c_smbus_data *data)
+{
+	unsigned int ret = 0; /* return code */
+	dma_addr_t dma_addr = 0; /* address of the data buffer */
+	u8 dma_size = 0;
+	enum dma_data_direction dma_direction = 0;
+	bool map_dma_flag = 0;
+	struct ismt_desc *desc;
+	struct ismt_priv *priv = i2c_get_adapdata(adap);
+
+	desc = &priv->hw[priv->head];
+
+	/* Initialize the descriptor */
+	memset(desc, 0, sizeof(struct ismt_desc));
+	desc->tgtaddr_rw = ISMT_DESC_ADDR_RW(addr, read_write);
+
+	/* Initialize common control bits */
+	desc->control |= ISMT_DESC_INT;
+
+	if (stop_on_error)
+		desc->control |= ISMT_DESC_SOE;
+
+	if ((flags & I2C_CLIENT_PEC) && (size != I2C_SMBUS_QUICK)
+		&& (size != I2C_SMBUS_I2C_BLOCK_DATA))
+		desc->control |= ISMT_DESC_PEC;
+
+	if (fair)
+		desc->control |= ISMT_DESC_FAIR;
+
+	switch (size) {
+	case I2C_SMBUS_QUICK:
+		dev_dbg(&priv->pci_dev->dev, "I2C_SMBUS_QUICK\n");
+		break;
+
+	case I2C_SMBUS_BYTE:
+		if (read_write == I2C_SMBUS_WRITE) {
+			/*
+			 * Send Byte
+			 * The command field contains the write data
+			 */
+			dev_dbg(&priv->pci_dev->dev, "I2C_SMBUS_BYTE:  WRITE\n");
+			desc->control |= ISMT_DESC_CWRL;
+			desc->wr_len_cmd = command;
+		} else {
+			/* Receive Byte */
+			dev_dbg(&priv->pci_dev->dev, "I2C_SMBUS_BYTE:  READ\n");
+			dma_size = 1;
+			dma_direction = DMA_FROM_DEVICE;
+			map_dma_flag = 1;
+			desc->rd_len = 1;
+		}
+
+		break;
+
+	case I2C_SMBUS_BYTE_DATA:
+		if (read_write == I2C_SMBUS_WRITE) {
+			/*
+			 * Write Byte
+			 * Command plus 1 data byte
+			 */
+			dev_dbg(&priv->pci_dev->dev, "I2C_SMBUS_BYTE_DATA:  WRITE\n");
+			desc->wr_len_cmd = 2;
+
+			/* Stuff the command ahead of the data in the buffer */
+			ismt_insert_cmd(data, command);
+			dma_size = 2;
+			dma_direction = DMA_TO_DEVICE;
+		} else {
+			/* Read Byte */
+			dev_dbg(&priv->pci_dev->dev, "I2C_SMBUS_BYTE_DATA:  READ\n");
+			desc->control |= ISMT_DESC_CWRL;
+			desc->wr_len_cmd = command;
+			desc->rd_len = 1;
+			dma_size = 1;
+			dma_direction = DMA_FROM_DEVICE;
+		}
+
+		map_dma_flag = 1;
+		break;
+
+	case I2C_SMBUS_WORD_DATA:
+		if (read_write == I2C_SMBUS_WRITE) {
+			/* Write Word */
+			dev_dbg(&priv->pci_dev->dev, "I2C_SMBUS_WORD_DATA:  WRITE\n");
+			desc->wr_len_cmd = 3;
+
+			/* Stuff the command ahead of the data in the buffer */
+			ismt_insert_cmd(data, command);
+			dma_size = 3;
+			dma_direction = DMA_TO_DEVICE;
+		} else {
+			/* Read Word */
+			dev_dbg(&priv->pci_dev->dev, "I2C_SMBUS_WORD_DATA:  READ\n");
+			desc->wr_len_cmd = command;
+			desc->control |= ISMT_DESC_CWRL;
+			desc->rd_len = 2;
+			dma_size = 2;
+			dma_direction = DMA_FROM_DEVICE;
+		}
+
+		map_dma_flag = 1;
+		break;
+
+	case I2C_SMBUS_PROC_CALL:
+		dev_dbg(&priv->pci_dev->dev, "I2C_SMBUS_PROC_CALL\n");
+		desc->wr_len_cmd = 3;
+		desc->rd_len = 2;
+
+		/* Stuff the command ahead of the data in the buffer */
+		ismt_insert_cmd(data, command);
+		dma_size = 3;
+		dma_direction = DMA_BIDIRECTIONAL;
+		map_dma_flag = 1;
+		break;
+
+	case I2C_SMBUS_BLOCK_DATA:
+		if (read_write == I2C_SMBUS_WRITE) {
+			/* Block Write */
+			dev_dbg(&priv->pci_dev->dev, "I2C_SMBUS_BLOCK_DATA:  WRITE\n");
+			dma_size = data->block[0] + 1;
+			dma_direction = DMA_TO_DEVICE;
+			desc->wr_len_cmd = dma_size;
+			desc->control |= ISMT_DESC_BLK;
+			ismt_insert_cmd(data, command);
+		} else {
+			/* Block Read */
+			dev_dbg(&priv->pci_dev->dev, "I2C_SMBUS_BLOCK_DATA:  READ\n");
+			dma_size = data->block[0] + 1;
+			dma_direction = DMA_FROM_DEVICE;
+			desc->rd_len = dma_size;
+			desc->wr_len_cmd = command;
+			desc->control |= (ISMT_DESC_BLK | ISMT_DESC_CWRL);
+		}
+
+		map_dma_flag = 1;
+		break;
+
+	default:
+		dev_err(&priv->pci_dev->dev, "Unsupported transaction %d\n",
+			size);
+		return -EOPNOTSUPP;
+	}
+
+	/* map the data buffer */
+	if (map_dma_flag) {
+		dev_dbg(&priv->pci_dev->dev,
+			" &priv->pci_dev->dev=%p\n", &priv->pci_dev->dev);
+		dev_dbg(&priv->pci_dev->dev, " data=%p\n", data);
+		dev_dbg(&priv->pci_dev->dev, " dma_size=%d\n", dma_size);
+		dev_dbg(&priv->pci_dev->dev,
+			" dma_direction=%d\n", dma_direction);
+
+		dma_addr = dma_map_single(&priv->pci_dev->dev,
+				      data,
+				      dma_size,
+				      dma_direction);
+
+		dev_dbg(&priv->pci_dev->dev, " dma_addr = 0x%016llX\n",
+			dma_addr);
+
+		desc->dptr_low = lower_32_bits(dma_addr);
+		desc->dptr_high = upper_32_bits(dma_addr);
+	}
+
+	INIT_COMPLETION(priv->cmp);
+
+	/* Add the descriptor */
+	ismt_submit_desc(adap);
+
+	/* Now we wait for interrupt completion, 1s */
+	ret = wait_for_completion_interruptible_timeout(&priv->cmp, HZ*1);
+
+	/* unmap the data buffer */
+	if (map_dma_flag)
+		dma_unmap_single(&adap->dev, dma_addr, dma_size, dma_direction);
+
+	if (ret < 0) {
+		dev_err(&priv->pci_dev->dev, "completion wait interrupted\n");
+		ret = -EIO;
+	} else if (ret == 0) {
+		dev_err(&priv->pci_dev->dev, "completion wait timed out\n");
+		ret = -ETIMEDOUT;
+	} else
+		/* do any post processing of the descriptor here */
+		ret = ismt_process_desc(adap);
+
+	/* Update the ring pointer */
+	priv->head++;
+	priv->head %= ISMT_DESC_ENTRIES;
+
+	return ret;
+}
+
+/**
+ * ismt_func() - report which i2c commands are supported by this adapter
+ * @adap: the i2c host adapter
+ */
+static u32 ismt_func(struct i2c_adapter *adap)
+{
+	return  I2C_FUNC_SMBUS_QUICK           |
+		I2C_FUNC_SMBUS_BYTE            |
+		I2C_FUNC_SMBUS_BYTE_DATA       |
+		I2C_FUNC_SMBUS_WORD_DATA       |
+		I2C_FUNC_SMBUS_PROC_CALL       |
+		I2C_FUNC_SMBUS_BLOCK_DATA      |
+		I2C_FUNC_SMBUS_PEC;
+}
+
+/**
+ * struct i2c_algorithm - the adapter algorithm and supported functionality
+ * @smbus_xfer: the adapter algorithm
+ * @functionality: functionality supported by the adapter
+ */
+static const struct i2c_algorithm smbus_algorithm = {
+	.smbus_xfer	= ismt_access,
+	.functionality	= ismt_func,
+};
+
+/**
+ * ismt_handle_isr() - interrupt handler bottom half
+ * @priv: iSMT private data
+ */
+static irqreturn_t ismt_handle_isr(struct ismt_priv *priv)
+{
+	complete(&priv->cmp);
+
+	return IRQ_HANDLED;
+}
+
+
+/**
+ * ismt_do_interrupt() - IRQ interrupt handler
+ * @vec: interrupt vector
+ * @data:  iSMT private data
+ */
+static irqreturn_t ismt_do_interrupt(int vec, void *data)
+{
+	u32 val;
+	struct ismt_priv *priv = (struct ismt_priv *)data;
+
+	/*
+	 * check to see it's our interrupt, return IRQ_NONE if not ours
+	 * since we are sharing interrupt
+	 */
+	val = readl(priv->smba + ISMT_MSTR_MSTS);
+
+	if (!(val & (ISMT_MSTS_MIS | ISMT_MSTS_MEIS)))
+		return IRQ_NONE;
+
+	if (val & ISMT_MSTS_MIS) {
+		/* completed successfully */
+		writel((val | ISMT_MSTS_MIS), priv->smba + ISMT_MSTR_MSTS);
+	} else {
+		/* completed with errors */
+		writel((val | ISMT_MSTS_MEIS), priv->smba + ISMT_MSTR_MSTS);
+	}
+
+	return ismt_handle_isr(priv);
+}
+
+/**
+ * ismt_do_msi_interrupt() - MSI interrupt handler
+ * @vec: interrupt vector
+ * @data:  iSMT private data
+ */
+static irqreturn_t ismt_do_msi_interrupt(int vec, void *data)
+{
+	struct ismt_priv *priv = (struct ismt_priv *)data;
+
+	return ismt_handle_isr(priv);
+}
+
+/**
+ * ismt_hw_init() - initialize the iSMT hardware
+ * @pdev: PCI-Express device
+ */
+static void __devinit ismt_hw_init(struct pci_dev *pdev)
+{
+	u32 val;
+	struct ismt_priv *priv = pci_get_drvdata(pdev);
+
+	/* initialize the Master Descriptor Base Address (MDBA) */
+	writeq(priv->io_rng_dma, priv->smba + ISMT_MSTR_MDBA);
+
+	/* initialize the Master Control Register (MCTRL) */
+	writel(ISMT_MCTRL_MEIE, priv->smba + ISMT_MSTR_MCTRL);
+
+	/* initialize the Master Status Register (MSTS) */
+	writel(0, priv->smba + ISMT_MSTR_MSTS);
+
+	/* initialize the Master Descriptor Size (MDS) */
+	val = readl(priv->smba + ISMT_MSTR_MDS);
+	writel((val & ~(ISMT_MDS_MDS)) | (ISMT_DESC_ENTRIES - 1),
+		priv->smba + ISMT_MSTR_MDS);
+
+#ifdef DEBUG_SLOW_HW
+	/*
+	 * initialize the SMBus speed to 80KHz for slow HW debuggers
+	 */
+	dev_dbg(&pdev->dev, " Setting SMBus clock to 80KHz\n");
+	val = readl(priv->smba + ISMT_SPGT);
+	writel(((val & ~(ISMT_SPGT_SPD)) | ISMT_SPGT_SPD_80K),
+	       priv->smba + ISMT_SPGT);
+#endif
+
+	dev_dbg(&pdev->dev, " priv->smba=%p\n", priv->smba);
+}
+
+/**
+ * ismt_init() - initialize the iSMT data structures
+ * @pdev: PCI-Express Device
+ */
+static int __devinit ismt_init(struct pci_dev *pdev)
+{
+	struct ismt_priv *priv = pci_get_drvdata(pdev);
+
+	priv->entries = ISMT_DESC_ENTRIES;
+
+	/* allocate memory for the descriptor */
+	priv->hw = dmam_alloc_coherent(&pdev->dev,
+				       (ISMT_DESC_ENTRIES
+					       * sizeof(struct ismt_desc)),
+				       &priv->io_rng_dma,
+				       GFP_KERNEL);
+	if (!priv->hw)
+		return -ENOMEM;
+
+	memset(priv->hw, 0, (ISMT_DESC_ENTRIES * sizeof(struct ismt_desc)));
+
+	priv->head = 0;
+	priv->tail = 0;
+	init_completion(&priv->cmp);
+
+	return 0;
+}
+
+/**
+ * ismt_int_init() - initialize interrupts
+ * @pdev: PCI-Express device
+ * @priv: iSMT private data
+ */
+static int ismt_int_init(struct pci_dev *pdev, struct ismt_priv *priv)
+{
+	int err;
+
+	/* Try using MSI interrupts */
+	err = pci_enable_msi(pdev);
+	if (err)
+		goto intx;
+
+	err = devm_request_irq(&pdev->dev,
+			       pdev->irq,
+			       ismt_do_msi_interrupt,
+			       0,
+			       "ismt-msi",
+			       priv);
+
+	if (err) {
+		pci_disable_msi(pdev);
+		goto intx;
+	}
+
+	goto done;
+
+	/* Try using legacy interrupts */
+intx:
+	err = devm_request_irq(&pdev->dev,
+			       pdev->irq,
+			       ismt_do_interrupt,
+			       IRQF_SHARED,
+			       "ismt-intx",
+			       priv);
+	if (err) {
+		dev_err(&pdev->dev, "no usable interrupts\n");
+		return -ENODEV;
+	}
+
+done:
+	return 0;
+}
+
+static struct pci_driver ismt_driver;
+
+/**
+ * ismt_probe() - probe for iSMT devices
+ * @pdev: PCI-Express device
+ * @id: PCI-Express device ID
+ */
+static int __devinit
+ismt_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	int err;
+	struct ismt_priv *priv;
+	unsigned long start, len;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	pci_set_drvdata(pdev, priv);
+	i2c_set_adapdata(&priv->adapter, priv);
+	priv->adapter.owner = THIS_MODULE;
+
+	priv->adapter.class = I2C_CLASS_HWMON;
+
+	priv->adapter.algo = &smbus_algorithm;
+	priv->pci_dev = pdev;
+
+	err = pcim_enable_device(pdev);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to enable SMBus PCI device (%d)\n",
+			err);
+		return err;
+	}
+
+	/* enable bus mastering */
+	pci_set_master(pdev);
+
+	/* Determine the address of the SMBus area */
+	start = pci_resource_start(pdev, SMBBAR);
+	if (!start) {
+		dev_err(&pdev->dev,
+			"SMBus base address uninitialized, upgrade BIOS\n");
+		return -ENODEV;
+	}
+
+	len = pci_resource_len(pdev, SMBBAR);
+	if (len == 0) {
+		dev_err(&pdev->dev,
+			"SMBus base address uninitialized, upgrade BIOS\n");
+		return -ENODEV;
+	}
+
+	dev_dbg(&priv->pci_dev->dev, " start=0x%lX\n", start);
+	dev_dbg(&priv->pci_dev->dev, " len=0x%lX\n", len);
+
+	err = acpi_check_resource_conflict(&pdev->resource[SMBBAR]);
+	if (err) {
+		dev_err(&pdev->dev, "ACPI resource conflict!\n");
+		return err;
+	}
+
+	err = pci_request_region(pdev, SMBBAR, ismt_driver.name);
+	if (err) {
+		dev_err(&pdev->dev,
+			"Failed to request SMBus region 0x%lx-0x%lx\n",
+			start, start + len);
+		return err;
+	}
+
+	priv->smba = pcim_iomap(pdev, SMBBAR, len);
+	if (!priv->smba) {
+		dev_err(&pdev->dev, "Unable to ioremap SMBus BAR\n");
+		err = -ENODEV;
+		goto fail;
+	}
+
+	err = pci_set_dma_mask(pdev, DMA_BIT_MASK(64));
+	if (err) {
+		err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+		if (err)
+			goto fail;
+		dev_warn(&pdev->dev, "Cannot DMA highmem\n");
+	}
+
+	err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
+	if (err) {
+		err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
+		if (err)
+			goto fail;
+		dev_warn(&pdev->dev, "Cannot DMA consistent highmem\n");
+	}
+
+	err = ismt_init(pdev);
+	if (err) {
+		err = -ENODEV;
+		goto fail;
+	}
+
+	ismt_hw_init(pdev);
+
+	err = ismt_int_init(pdev, priv);
+	if (err)
+		goto fail;
+
+	/* set up the sysfs linkage to our parent device */
+	priv->adapter.dev.parent = &pdev->dev;
+
+	/* number of retries on lost arbitration */
+	priv->adapter.retries = ISMT_MAX_RETRIES;
+
+	snprintf(priv->adapter.name, sizeof(priv->adapter.name),
+		 "SMBus iSMT adapter at %p", priv->smba);
+	err = i2c_add_adapter(&priv->adapter);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to add SMBus iSMT adapter\n");
+		err = -ENODEV;
+		goto fail;
+	}
+	return 0;
+
+fail:
+	pci_release_region(pdev, SMBBAR);
+	return err;
+}
+
+/**
+ * ismt_remove() - release driver resources
+ * @pdev: PCI-Express device
+ */
+static void __devexit ismt_remove(struct pci_dev *pdev)
+{
+	struct ismt_priv *priv = pci_get_drvdata(pdev);
+
+	writel(ISMT_GCTRL_SRST, priv->smba + ISMT_GR_GCTRL);
+	i2c_del_adapter(&priv->adapter);
+	pci_release_region(pdev, SMBBAR);
+}
+
+/**
+ * ismt_suspend() - place the device in suspend
+ * @pdev: PCI-Express device
+ * @mesg: PM message
+ */
+#ifdef CONFIG_PM
+static int ismt_suspend(struct pci_dev *pdev, pm_message_t mesg)
+{
+	pci_save_state(pdev);
+	pci_set_power_state(pdev, pci_choose_state(pdev, mesg));
+	return 0;
+}
+
+/**
+ * ismt_resume() - PCI resume code
+ * @pdev: PCI-Express device
+ */
+static int ismt_resume(struct pci_dev *pdev)
+{
+	pci_set_power_state(pdev, PCI_D0);
+	pci_restore_state(pdev);
+	return pci_enable_device(pdev);
+}
+
+#else
+
+#define ismt_suspend NULL
+#define ismt_resume NULL
+
+#endif
+
+static struct pci_driver ismt_driver = {
+	.name = "ismt_smbus",
+	.id_table = ismt_ids,
+	.probe = ismt_probe,
+	.remove = __devexit_p(ismt_remove),
+	.suspend = ismt_suspend,
+	.resume = ismt_resume,
+};
+
+/**
+ * i2c_ismt_init() - iSMT driver initialization
+ */
+static int __init i2c_ismt_init(void)
+{
+	pr_debug("Loading the iSMT SMBus driver\n");
+	return pci_register_driver(&ismt_driver);
+}
+
+/**
+ * i2c_ismt_exit() - iSMT driver exit code
+ */
+static void __exit i2c_ismt_exit(void)
+{
+	pr_debug("Unloading iSMT SMBus driver\n");
+	pci_unregister_driver(&ismt_driver);
+}
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Bill E. Brown <bill.e.brown@xxxxxxxxx>");
+MODULE_DESCRIPTION("Intel SMBus Message Transport (iSMT) driver");
+
+module_init(i2c_ismt_init);
+module_exit(i2c_ismt_exit);
+
diff --git a/drivers/i2c/busses/i2c-ismt.h b/drivers/i2c/busses/i2c-ismt.h
new file mode 100644
index 0000000..e9c10e1
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ismt.h
@@ -0,0 +1,111 @@
+#ifndef _I2C_ISMT_H_
+#define _I2C_ISMT_H_
+
+/* PCI Address Constants */
+#define SMBBAR		0
+
+/* PCI DIDs for Briarwood's pair of SMBus Message Transport (SMT) Devices */
+#define PCI_DEVICE_ID_INTEL_BWD_SMBUS_SMT0 0x0c59
+#define PCI_DEVICE_ID_INTEL_BWD_SMBUS_SMT1 0x0c5a
+
+#define ISMT_DESC_ENTRIES 32 /* number of descritor entries */
+#define ISMT_MAX_RETRIES 3   /* number of SMBus retries to attempt */
+
+/* Hardware Descriptor Constants - Control Field */
+#define ISMT_DESC_CWRL  0x01    /* Command/Write Length */
+#define ISMT_DESC_BLK   0X04    /* Perform Block Transaction */
+#define ISMT_DESC_FAIR  0x08    /* Set fairness flag upon successful arbit. */
+#define ISMT_DESC_PEC   0x10    /* Packet Error Code */
+#define ISMT_DESC_I2C   0x20    /* I2C Enable */
+#define ISMT_DESC_INT   0x40    /* Interrupt */
+#define ISMT_DESC_SOE   0x80    /* Stop On Error */
+
+/* Hardware Descriptor Constants - Status Field */
+#define ISMT_DESC_SCS   0x01    /* Success */
+#define ISMT_DESC_DLTO  0x04    /* Data Low Time Out */
+#define ISMT_DESC_NAK   0x08    /* NAK Received */
+#define ISMT_DESC_CRC   0x10    /* CRC Error */
+#define ISMT_DESC_CLTO  0x20    /* Clock Low Time Out */
+#define ISMT_DESC_COL   0x40    /* Collisions */
+#define ISMT_DESC_LPR   0x80    /* Large Packet Received */
+
+/* Hardware Descriptor Masks */
+#define ISMT_DESC_ADDR  0x7f    /* I2C/SMB address mask */
+#define ISMT_DESC_RW    0x01    /* Read/Write bit mask */
+
+/* Macros */
+#define ISMT_DESC_ADDR_RW(addr, rw) (((addr & ISMT_DESC_ADDR) << 1)	\
+				     | (rw & ISMT_DESC_RW))
+
+/* iSMT General Register address offsets (SMBAR + <addr>) */
+#define ISMT_GR_GCTRL      0x000 /* General Control */
+#define ISMT_GR_SMTICL     0x008 /* SMT Interrupt Cause Location */
+#define ISMT_GR_ERRINTMSK  0x010 /* Error Interrupt Mask */
+#define ISMT_GR_ERRAERMSK  0x014 /* Error AER Mask */
+#define ISMT_GR_ERRSTS     0x018 /* Error Status */
+#define ISMT_GR_ERRINFO    0x01c /* Error Information */
+
+/* iSMT Master Registers */
+#define ISMT_MSTR_MDBA    0x100  /* Master Descriptor Base Address */
+#define ISMT_MSTR_MCTRL   0x108  /* Master Control */
+#define ISMT_MSTR_MSTS    0x10c  /* Master Status */
+#define ISMT_MSTR_MDS     0x110  /* Master Descriptor Size */
+#define ISMT_MSTR_RPOLICY 0x114  /* Retry Policy */
+
+/* iSMT Miscellaneous Registers */
+#define ISMT_SPGT  0x300  /* SMBus PHY Global Timing */
+
+/* General Control Register (GCTRL) bit definitions */
+#define ISMT_GCTRL_TRST 0x04    /* Target Reset */
+#define ISMT_GCTRL_KILL 0x08    /* Kill */
+#define ISMT_GCTRL_SRST 0x40    /* Soft Reset */
+
+/* Master Control Register (MCTRL) bit definitions */
+#define ISMT_MCTRL_SS    0x01       /* Start/Stop */
+#define ISMT_MCTRL_MEIE  0x10       /* Master Error Interrupt Enable */
+#define ISMT_MCTRL_FMHP  0x00ff0000 /* Firmware Master Head Pointer (FMHP) */
+
+/* Master Status Register (MSTS) bit definitions */
+#define ISMT_MSTS_HMTP  0xff0000 /* HW Master Tail Pointer (HMTP) */
+#define ISMT_MSTS_MIS   0x20     /* Master Interrupt Status (MIS) */
+#define ISMT_MSTS_MEIS  0x10     /* Master Error Interrupt Status (MEIS) */
+#define ISMT_MSTS_IP    0x01     /* In Progress */
+
+/* Master Descriptor Size (MDS) bit definitions */
+#define ISMT_MDS_MDS  0xFF /* Master Descriptor Size mask (MDS) */
+
+/* SMBus PHY Global Timing Register (SPGT) bit definitions */
+#define ISMT_SPGT_SPD     0xc0000000   /* SMBus Speed mask */
+#define ISMT_SPGT_SPD_80K (0x01 << 30) /* 80 KHz */
+
+/* MSI Control Register (MSICTL) bit definitions */
+#define ISMT_MSICTL_MSIE 0x01 /* MSI Enable */
+
+/* iSMT Hardware Descriptor */
+struct ismt_desc {
+	u8 tgtaddr_rw; /* target address & r/w bit */
+	u8 wr_len_cmd; /* write length in bytes or a command */
+	u8 rd_len; /* read length */
+	u8 control; /* control bits */
+	u8 status; /* status bits */
+	u8 retry; /* collision retry and retry count */
+	u8 rxbytes; /* received bytes */
+	u8 txbytes; /* transmitted bytes */
+	u32 dptr_low; /* lower 32 bit of the data pointer */
+	u32 dptr_high; /* upper 32 bit of the data pointer */
+};
+
+struct ismt_priv {
+	struct i2c_adapter adapter;
+	void *smba; /* PCI BAR */
+	struct pci_dev *pci_dev;
+	struct ismt_ring_ent **ring; /* housekeeping struct pointer */
+	struct ismt_desc *hw; /* virtual base address of the descriptor */
+	dma_addr_t io_rng_dma; /* hardware base address of the descriptor */
+	int entries; /* number of descriptor entries */
+	u8 head; /* ring buffer head pointer */
+	u8 tail; /* ring buffer tail pointer */
+	struct completion cmp; /* interrupt completion */
+};
+
+#endif
-- 
1.6.2.5

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