Patchwork [v7] i2c: Adding support for Intel iSMT SMBus 2.0 host controller

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Submitter Neil Horman
Date Feb. 4, 2013, 7:54 p.m.
Message ID <1360007650-26272-1-git-send-email-nhorman@tuxdriver.com>
Download mbox | patch
Permalink /patch/218052/
State Accepted
Headers show

Comments

Neil Horman - Feb. 4, 2013, 7:54 p.m.
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: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Bill Brown <bill.e.brown@intel.com>
Tested-by: Seth Heasley <seth.heasley@intel.com>
CC: Seth Heasley <seth.heasley@intel.com>
CC: Jean Delvare <khali@linux-fr.org>

---
General note - Seth had mentioned to me that he was unable to get writes to work
on his system.  I'm not sure of the details, but I've done some rudimentary
read/write testing here on my system, and it seems to work well (for the limited
testing I can do).  Seth if you could please provide details of your testing, or
give this patch a try, I would appreciate it.

I've setup a system with this SMBus device on it, and managed to successfully
preform both read and write operations with it.  Specifically I used i2cget to
check byte and word reads, i2cset to check byte, word and block writes, and
i2cdump to check block reads.  Seth is also looking into getting documentation
for the dma descriptor format, but using the additional descriptor debug dumping
statements I added I was able to verify experimentally that the rxbytes value is
the correct one to use in the run time limitation of the read side memcpy.

Jean, I've also tested your patch using the same methodoloy you and I have
posted previously, and with your patch I concur, It seems to work correctly to
the device at bus address 0x54

Change notes for V5)
* Remove __devexit, __devinit macros

* Convert module parameter to use units of khz

* Update Description to reflect current pci db

* Improve KConfig dependencies

* Improve PCI device id names

* Reduce dma buffer size to appropriate value and check mapping result

* Fix build failure resulting from missing readq definition

* Limit use of memcpy and copy length in ismt_process_desc

* Fix off by one error in dma_size

* Convert driver to uninterruptible wait on dma transfers

* Add spped sync with bus_speed module option

* Misc cleanups and fixes

* Fix FTBFS when CONFIG_DYNAMIC_DEBUG is off

Change notes for v6)

* More Misc typos/grammatical fixes/etc

* Fixed some build warnings

* Fixed some checkpatch errors

* Fixed read check for memcpy

* updated memcpy's to limit read/write length to amount of data returned by hw

* Fixed ETIMEOUT return code handling in ismt_access

* Fixed updating of speed in bus_speed module paramter

* Enhanced descriptor debug dumping to aid in validation

Change notes for v7)

* Few final typos

* Fixed the printing or readq values in debug code

* Added Jeans patch to fix quick and byte reads/writes
---
 Documentation/i2c/busses/i2c-ismt |  36 ++
 drivers/i2c/busses/Kconfig        |  10 +
 drivers/i2c/busses/Makefile       |   1 +
 drivers/i2c/busses/i2c-ismt.c     | 963 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 1010 insertions(+)
 create mode 100644 Documentation/i2c/busses/i2c-ismt
 create mode 100644 drivers/i2c/busses/i2c-ismt.c
Seth Heasley - Feb. 5, 2013, 1:13 a.m.
Hi Neil,

>General note - Seth had mentioned to me that he was unable to get writes to
>work on his system.  I'm not sure of the details, but I've done some
>rudimentary read/write testing here on my system, and it seems to work well
>(for the limited testing I can do).  Seth if you could please provide details of
>your testing, or give this patch a try, I would appreciate it.

Whatever issues I was having with the previous patch, they appear to be resolved.  I was able to do testing similar to yours, albeit using an external slave device.  I'm not seeing the device at 0x54 on my system.  But reads and writes both worked.

-Seth

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Jean Delvare - Feb. 5, 2013, 7:16 a.m.
On Tue, 5 Feb 2013 01:13:56 +0000, Heasley, Seth wrote:
> Hi Neil,
> 
> >General note - Seth had mentioned to me that he was unable to get writes to
> >work on his system.  I'm not sure of the details, but I've done some
> >rudimentary read/write testing here on my system, and it seems to work well
> >(for the limited testing I can do).  Seth if you could please provide details of
> >your testing, or give this patch a try, I would appreciate it.
> 
> Whatever issues I was having with the previous patch, they appear to be resolved.  I was able to do testing similar to yours, albeit using an external slave device.  I'm not seeing the device at 0x54 on my system.  But reads and writes both worked.

Great news, thanks for testing and reporting!
Neil Horman - Feb. 5, 2013, 2:52 p.m.
On Tue, Feb 05, 2013 at 08:16:42AM +0100, Jean Delvare wrote:
> On Tue, 5 Feb 2013 01:13:56 +0000, Heasley, Seth wrote:
> > Hi Neil,
> > 
> > >General note - Seth had mentioned to me that he was unable to get writes to
> > >work on his system.  I'm not sure of the details, but I've done some
> > >rudimentary read/write testing here on my system, and it seems to work well
> > >(for the limited testing I can do).  Seth if you could please provide details of
> > >your testing, or give this patch a try, I would appreciate it.
> > 
> > Whatever issues I was having with the previous patch, they appear to be resolved.  I was able to do testing similar to yours, albeit using an external slave device.  I'm not seeing the device at 0x54 on my system.  But reads and writes both worked.
> 
> Great news, thanks for testing and reporting!
> 
Yes, thank you Seth.  I think that puts version 7 at tested by all three of us,
and working.  Jean, any other fixups you feel are needed?

Neil

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Jean Delvare - Feb. 5, 2013, 4:41 p.m.
On Tue, 5 Feb 2013 09:52:30 -0500, Neil Horman wrote:
> On Tue, Feb 05, 2013 at 08:16:42AM +0100, Jean Delvare wrote:
> > On Tue, 5 Feb 2013 01:13:56 +0000, Heasley, Seth wrote:
> > > Hi Neil,
> > > 
> > > >General note - Seth had mentioned to me that he was unable to get writes to
> > > >work on his system.  I'm not sure of the details, but I've done some
> > > >rudimentary read/write testing here on my system, and it seems to work well
> > > >(for the limited testing I can do).  Seth if you could please provide details of
> > > >your testing, or give this patch a try, I would appreciate it.
> > > 
> > > Whatever issues I was having with the previous patch, they appear to be resolved.  I was able to do testing similar to yours, albeit using an external slave device.  I'm not seeing the device at 0x54 on my system.  But reads and writes both worked.
> > 
> > Great news, thanks for testing and reporting!
> > 
> Yes, thank you Seth.  I think that puts version 7 at tested by all three of us,
> and working.  Jean, any other fixups you feel are needed?

No, it looks good now. Wolfram, please queue this new driver for kernel
3.9.

I have also made the driver available as a standalone source file at:
  http://khali.linux-fr.org/devel/misc/i2c-ismt/
Testers can be pointed to this location. This version of the driver has
some compatibility code to build at least down to kernel version 3.0.
Jean Delvare - Feb. 5, 2013, 4:41 p.m.
On Mon,  4 Feb 2013 14:54:10 -0500, Neil Horman wrote:
> 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: Neil Horman <nhorman@tuxdriver.com>
> Signed-off-by: Bill Brown <bill.e.brown@intel.com>
> Tested-by: Seth Heasley <seth.heasley@intel.com>
> CC: Seth Heasley <seth.heasley@intel.com>
> CC: Jean Delvare <khali@linux-fr.org>
> (...)

Reviewed-by: Jean Delvare <khali@linux-fr.org>
Wolfram Sang - Feb. 10, 2013, 3:02 p.m.
On Mon, Feb 04, 2013 at 02:54:10PM -0500, Neil Horman wrote:
> 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: Neil Horman <nhorman@tuxdriver.com>
> Signed-off-by: Bill Brown <bill.e.brown@intel.com>
> Tested-by: Seth Heasley <seth.heasley@intel.com>

Thanks, applied to for-next!

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Neil Horman - March 5, 2013, 2:22 p.m.
On Sun, Feb 10, 2013 at 04:02:05PM +0100, Wolfram Sang wrote:
> On Mon, Feb 04, 2013 at 02:54:10PM -0500, Neil Horman wrote:
> > 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: Neil Horman <nhorman@tuxdriver.com>
> > Signed-off-by: Bill Brown <bill.e.brown@intel.com>
> > Tested-by: Seth Heasley <seth.heasley@intel.com>
> 
> Thanks, applied to for-next!
> 
> 
Wolfram-
	Hey, sorry to bother you, but I just wanted to check on this patch. I
see its accepted in patchwork, but I haven't seen it show up in your git tree
yet, and I was really hoping this would make 3.9.  Since we're in the -rc run
for that release, i wanted to check with you to see if you were planning to push
it.

Thanks!
Neil

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Jean Delvare - March 5, 2013, 2:42 p.m.
Hi Neil,

On Tue, 5 Mar 2013 09:22:25 -0500, Neil Horman wrote:
> On Sun, Feb 10, 2013 at 04:02:05PM +0100, Wolfram Sang wrote:
> > On Mon, Feb 04, 2013 at 02:54:10PM -0500, Neil Horman wrote:
> > > 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: Neil Horman <nhorman@tuxdriver.com>
> > > Signed-off-by: Bill Brown <bill.e.brown@intel.com>
> > > Tested-by: Seth Heasley <seth.heasley@intel.com>
> > 
> > Thanks, applied to for-next!
> > 
> > 
> Wolfram-
> 	Hey, sorry to bother you, but I just wanted to check on this patch. I
> see its accepted in patchwork, but I haven't seen it show up in your git tree
> yet, and I was really hoping this would make 3.9.  Since we're in the -rc run
> for that release, i wanted to check with you to see if you were planning to push
> it.

Your driver is already in 3.9, see:

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/log/drivers/i2c/busses/i2c-ismt.c
Neil Horman - March 5, 2013, 4:09 p.m.
On Tue, Mar 05, 2013 at 03:42:53PM +0100, Jean Delvare wrote:
> Hi Neil,
> 
> On Tue, 5 Mar 2013 09:22:25 -0500, Neil Horman wrote:
> > On Sun, Feb 10, 2013 at 04:02:05PM +0100, Wolfram Sang wrote:
> > > On Mon, Feb 04, 2013 at 02:54:10PM -0500, Neil Horman wrote:
> > > > 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: Neil Horman <nhorman@tuxdriver.com>
> > > > Signed-off-by: Bill Brown <bill.e.brown@intel.com>
> > > > Tested-by: Seth Heasley <seth.heasley@intel.com>
> > > 
> > > Thanks, applied to for-next!
> > > 
> > > 
> > Wolfram-
> > 	Hey, sorry to bother you, but I just wanted to check on this patch. I
> > see its accepted in patchwork, but I haven't seen it show up in your git tree
> > yet, and I was really hoping this would make 3.9.  Since we're in the -rc run
> > for that release, i wanted to check with you to see if you were planning to push
> > it.
> 
> Your driver is already in 3.9, see:
> 
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/log/drivers/i2c/busses/i2c-ismt.c
> 
Crud, I was on the wrong branch.  Sorry for the noise!
Neil

> -- 
> Jean Delvare
> 
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Patch

diff --git a/Documentation/i2c/busses/i2c-ismt b/Documentation/i2c/busses/i2c-ismt
new file mode 100644
index 0000000..7373558
--- /dev/null
+++ b/Documentation/i2c/busses/i2c-ismt
@@ -0,0 +1,36 @@ 
+Kernel driver i2c-ismt
+
+Supported adapters:
+  * Intel S12xx series SOCs
+
+Authors:
+	Bill Brown <bill.e.brown@intel.com>
+
+
+Module Parameters
+-----------------
+
+* bus_speed (unsigned int)
+Allows changing of the bus speed.  Normally, the bus speed is set by the BIOS
+and never needs to be changed.  However, some SMBus analyzers are too slow for
+monitoring the bus during debug, thus the need for this module parameter.
+Specify the bus speed in kHz.
+Available bus frequency settings:
+  0  no change
+  80 kHz
+  100 kHz
+  400 kHz
+  1000 kHz
+
+
+Description
+-----------
+
+The S12xx series of SOCs have a pair of integrated SMBus 2.0 controllers
+targeted primarily at the microserver and storage markets.
+
+The S12xx series contain a pair of PCI functions.  An output of lspci will show
+something similar to the following:
+
+  00:13.0 System peripheral: Intel Corporation Centerton SMBus 2.0 Controller 0
+  00:13.1 System peripheral: Intel Corporation Centerton SMBus 2.0 Controller 1
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index bdca511..0bb7ff4 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -121,6 +121,16 @@  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 && X86
+	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 6181f3f..23c9d55 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -14,6 +14,7 @@  obj-$(CONFIG_I2C_AMD756_S4882)	+= i2c-amd756-s4882.o
 obj-$(CONFIG_I2C_AMD8111)	+= i2c-amd8111.o
 obj-$(CONFIG_I2C_I801)		+= i2c-i801.o
 obj-$(CONFIG_I2C_ISCH)		+= i2c-isch.o
+obj-$(CONFIG_I2C_ISMT)		+= i2c-ismt.o
 obj-$(CONFIG_I2C_NFORCE2)	+= i2c-nforce2.o
 obj-$(CONFIG_I2C_NFORCE2_S4985)	+= i2c-nforce2-s4985.o
 obj-$(CONFIG_I2C_PIIX4)		+= i2c-piix4.o
diff --git a/drivers/i2c/busses/i2c-ismt.c b/drivers/i2c/busses/i2c-ismt.c
new file mode 100644
index 0000000..3f7a9cb
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ismt.c
@@ -0,0 +1,963 @@ 
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * 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
+ *
+ * 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) in the Intel Atom Processor
+ *  S12xx Product Family.
+ *
+ *  Features supported by this driver:
+ *  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/completion.h>
+#include <linux/dma-mapping.h>
+#include <linux/i2c.h>
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+
+#include <asm-generic/io-64-nonatomic-lo-hi.h>
+
+/* PCI Address Constants */
+#define SMBBAR		0
+
+/* PCI DIDs for the Intel SMBus Message Transport (SMT) Devices */
+#define PCI_DEVICE_ID_INTEL_S1200_SMT0	0x0c59
+#define PCI_DEVICE_ID_INTEL_S1200_SMT1	0x0c5a
+
+#define ISMT_DESC_ENTRIES	32	/* number of descriptor 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 */
+
+/* Macros */
+#define ISMT_DESC_ADDR_RW(addr, rw) (((addr) << 1) | (rw))
+
+/* iSMT General Register address offsets (SMBBAR + <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 Ptr (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 Int Status (MEIS) */
+#define ISMT_MSTS_IP	0x01		/* In Progress */
+
+/* Master Descriptor Size (MDS) bit definitions */
+#define ISMT_MDS_MASK	0xff	/* Master Descriptor Size mask (MDS) */
+
+/* SMBus PHY Global Timing Register (SPGT) bit definitions */
+#define ISMT_SPGT_SPD_MASK	0xc0000000	/* SMBus Speed mask */
+#define ISMT_SPGT_SPD_80K	0x00		/* 80 kHz */
+#define ISMT_SPGT_SPD_100K	(0x1 << 30)	/* 100 kHz */
+#define ISMT_SPGT_SPD_400K	(0x2 << 30)	/* 400 kHz */
+#define ISMT_SPGT_SPD_1M	(0x3 << 30)	/* 1 MHz */
+
+
+/* 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 */
+} __packed;
+
+struct ismt_priv {
+	struct i2c_adapter adapter;
+	void *smba;				/* PCI BAR */
+	struct pci_dev *pci_dev;
+	struct ismt_desc *hw;			/* descriptor virt base addr */
+	dma_addr_t io_rng_dma;			/* descriptor HW base addr */
+	u8 head;				/* ring buffer head pointer */
+	struct completion cmp;			/* interrupt completion */
+	u8 dma_buffer[I2C_SMBUS_BLOCK_MAX + 1];	/* temp R/W data buffer */
+	bool using_msi;				/* type of interrupt flag */
+};
+
+/**
+ * ismt_ids - 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_S1200_SMT0) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_S1200_SMT1) },
+	{ 0, }
+};
+
+MODULE_DEVICE_TABLE(pci, ismt_ids);
+
+/* Bus speed control bits for slow debuggers - refer to the docs for usage */
+static unsigned int bus_speed;
+module_param(bus_speed, uint, S_IRUGO);
+MODULE_PARM_DESC(bus_speed, "Bus Speed in kHz (0 = BIOS default)");
+
+/**
+ * __ismt_desc_dump() - dump the contents of a specific descriptor
+ */
+static void __ismt_desc_dump(struct device *dev, const struct ismt_desc *desc)
+{
+
+	dev_dbg(dev, "Descriptor struct:  %p\n", desc);
+	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);
+}
+/**
+ * ismt_desc_dump() - dump the contents of a descriptor for debug purposes
+ * @priv: iSMT private data
+ */
+static void ismt_desc_dump(struct ismt_priv *priv)
+{
+	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);
+	__ismt_desc_dump(dev, desc);
+}
+
+/**
+ * ismt_gen_reg_dump() - dump the iSMT General Registers
+ * @priv: iSMT private data
+ */
+static void ismt_gen_reg_dump(struct ismt_priv *priv)
+{
+	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%016llX\n",
+		priv->smba + ISMT_GR_SMTICL,
+		(long long unsigned int)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));
+}
+
+/**
+ * ismt_mstr_reg_dump() - dump the iSMT Master Registers
+ * @priv: iSMT private data
+ */
+static void ismt_mstr_reg_dump(struct ismt_priv *priv)
+{
+	struct device *dev = &priv->pci_dev->dev;
+
+	dev_dbg(dev, "Dump of the iSMT Master Registers\n");
+	dev_dbg(dev, "  MDBA..... : (0x%p)=0x%016llX\n",
+		priv->smba + ISMT_MSTR_MDBA,
+		(long long unsigned int)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));
+}
+
+/**
+ * ismt_submit_desc() - add a descriptor to the ring
+ * @priv: iSMT private data
+ */
+static void ismt_submit_desc(struct ismt_priv *priv)
+{
+	uint fmhp;
+	uint val;
+
+	ismt_desc_dump(priv);
+	ismt_gen_reg_dump(priv);
+	ismt_mstr_reg_dump(priv);
+
+	/* 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);
+}
+
+/**
+ * ismt_process_desc() - handle the completion of the descriptor
+ * @desc: the iSMT hardware descriptor
+ * @data: data buffer from the upper layer
+ * @priv: ismt_priv struct holding our dma buffer
+ * @size: SMBus transaction type
+ * @read_write: flag to indicate if this is a read or write
+ */
+static int ismt_process_desc(const struct ismt_desc *desc,
+			     union i2c_smbus_data *data,
+			     struct ismt_priv *priv, int size,
+			     char read_write)
+{
+	u8 *dma_buffer = priv->dma_buffer;
+
+	dev_dbg(&priv->pci_dev->dev, "Processing completed descriptor\n");
+	__ismt_desc_dump(&priv->pci_dev->dev, desc);
+
+	if (desc->status & ISMT_DESC_SCS) {
+		if (read_write == I2C_SMBUS_WRITE &&
+		    size != I2C_SMBUS_PROC_CALL)
+			return 0;
+
+		switch (size) {
+		case I2C_SMBUS_BYTE:
+		case I2C_SMBUS_BYTE_DATA:
+			data->byte = dma_buffer[0];
+			break;
+		case I2C_SMBUS_WORD_DATA:
+		case I2C_SMBUS_PROC_CALL:
+			data->word = dma_buffer[0] | (dma_buffer[1] << 8);
+			break;
+		case I2C_SMBUS_BLOCK_DATA:
+			memcpy(&data->block[1], dma_buffer, desc->rxbytes);
+			data->block[0] = desc->rxbytes;
+			break;
+		}
+		return 0;
+	}
+
+	if (likely(desc->status & ISMT_DESC_NAK))
+		return -ENXIO;
+
+	if (desc->status & ISMT_DESC_CRC)
+		return -EBADMSG;
+
+	if (desc->status & ISMT_DESC_COL)
+		return -EAGAIN;
+
+	if (desc->status & ISMT_DESC_LPR)
+		return -EPROTO;
+
+	if (desc->status & (ISMT_DESC_DLTO | ISMT_DESC_CLTO))
+		return -ETIMEDOUT;
+
+	return -EIO;
+}
+
+/**
+ * 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)
+{
+	int ret;
+	dma_addr_t dma_addr = 0; /* address of the data buffer */
+	u8 dma_size = 0;
+	enum dma_data_direction dma_direction = 0;
+	struct ismt_desc *desc;
+	struct ismt_priv *priv = i2c_get_adapdata(adap);
+	struct device *dev = &priv->pci_dev->dev;
+
+	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 */
+	if (likely(priv->using_msi))
+		desc->control = ISMT_DESC_INT | ISMT_DESC_FAIR;
+	else
+		desc->control = ISMT_DESC_FAIR;
+
+	if ((flags & I2C_CLIENT_PEC) && (size != I2C_SMBUS_QUICK)
+	    && (size != I2C_SMBUS_I2C_BLOCK_DATA))
+		desc->control |= ISMT_DESC_PEC;
+
+	switch (size) {
+	case I2C_SMBUS_QUICK:
+		dev_dbg(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(dev, "I2C_SMBUS_BYTE:  WRITE\n");
+			desc->control |= ISMT_DESC_CWRL;
+			desc->wr_len_cmd = command;
+		} else {
+			/* Receive Byte */
+			dev_dbg(dev, "I2C_SMBUS_BYTE:  READ\n");
+			dma_size = 1;
+			dma_direction = DMA_FROM_DEVICE;
+			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(dev, "I2C_SMBUS_BYTE_DATA:  WRITE\n");
+			desc->wr_len_cmd = 2;
+			dma_size = 2;
+			dma_direction = DMA_TO_DEVICE;
+			priv->dma_buffer[0] = command;
+			priv->dma_buffer[1] = data->byte;
+		} else {
+			/* Read Byte */
+			dev_dbg(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;
+		}
+		break;
+
+	case I2C_SMBUS_WORD_DATA:
+		if (read_write == I2C_SMBUS_WRITE) {
+			/* Write Word */
+			dev_dbg(dev, "I2C_SMBUS_WORD_DATA:  WRITE\n");
+			desc->wr_len_cmd = 3;
+			dma_size = 3;
+			dma_direction = DMA_TO_DEVICE;
+			priv->dma_buffer[0] = command;
+			priv->dma_buffer[1] = data->word & 0xff;
+			priv->dma_buffer[2] = data->word >> 8;
+		} else {
+			/* Read Word */
+			dev_dbg(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;
+		}
+		break;
+
+	case I2C_SMBUS_PROC_CALL:
+		dev_dbg(dev, "I2C_SMBUS_PROC_CALL\n");
+		desc->wr_len_cmd = 3;
+		desc->rd_len = 2;
+		dma_size = 3;
+		dma_direction = DMA_BIDIRECTIONAL;
+		priv->dma_buffer[0] = command;
+		priv->dma_buffer[1] = data->word & 0xff;
+		priv->dma_buffer[2] = data->word >> 8;
+		break;
+
+	case I2C_SMBUS_BLOCK_DATA:
+		if (read_write == I2C_SMBUS_WRITE) {
+			/* Block Write */
+			dev_dbg(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;
+			priv->dma_buffer[0] = command;
+			memcpy(&priv->dma_buffer[1], &data->block[1], dma_size);
+		} else {
+			/* Block Read */
+			dev_dbg(dev, "I2C_SMBUS_BLOCK_DATA:  READ\n");
+			dma_size = I2C_SMBUS_BLOCK_MAX;
+			dma_direction = DMA_FROM_DEVICE;
+			desc->rd_len = dma_size;
+			desc->wr_len_cmd = command;
+			desc->control |= (ISMT_DESC_BLK | ISMT_DESC_CWRL);
+		}
+		break;
+
+	default:
+		dev_err(dev, "Unsupported transaction %d\n",
+			size);
+		return -EOPNOTSUPP;
+	}
+
+	/* map the data buffer */
+	if (dma_size != 0) {
+		dev_dbg(dev, " dev=%p\n", dev);
+		dev_dbg(dev, " data=%p\n", data);
+		dev_dbg(dev, " dma_buffer=%p\n", priv->dma_buffer);
+		dev_dbg(dev, " dma_size=%d\n", dma_size);
+		dev_dbg(dev, " dma_direction=%d\n", dma_direction);
+
+		dma_addr = dma_map_single(dev,
+				      priv->dma_buffer,
+				      dma_size,
+				      dma_direction);
+
+		if (dma_mapping_error(dev, dma_addr)) {
+			dev_err(dev, "Error in mapping dma buffer %p\n",
+				priv->dma_buffer);
+			return -EIO;
+		}
+
+		dev_dbg(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(priv);
+
+	/* Now we wait for interrupt completion, 1s */
+	ret = wait_for_completion_timeout(&priv->cmp, HZ*1);
+
+	/* unmap the data buffer */
+	if (dma_size != 0)
+		dma_unmap_single(&adap->dev, dma_addr, dma_size, dma_direction);
+
+	if (unlikely(!ret)) {
+		dev_err(dev, "completion wait timed out\n");
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	/* do any post processing of the descriptor here */
+	ret = ismt_process_desc(desc, data, priv, size, read_write);
+
+out:
+	/* 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;
+}
+
+/**
+ * smbus_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 = 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;
+	else
+		writel(val | ISMT_MSTS_MIS | 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)
+{
+	return ismt_handle_isr(data);
+}
+
+/**
+ * ismt_hw_init() - initialize the iSMT hardware
+ * @priv: iSMT private data
+ */
+static void ismt_hw_init(struct ismt_priv *priv)
+{
+	u32 val;
+	struct device *dev = &priv->pci_dev->dev;
+
+	/* 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_MASK) | (ISMT_DESC_ENTRIES - 1),
+		priv->smba + ISMT_MSTR_MDS);
+
+	/*
+	 * Set the SMBus speed (could use this for slow HW debuggers)
+	 */
+
+	val = readl(priv->smba + ISMT_SPGT);
+
+	switch (bus_speed) {
+	case 0:
+		break;
+
+	case 80:
+		dev_dbg(dev, "Setting SMBus clock to 80 kHz\n");
+		writel(((val & ~ISMT_SPGT_SPD_MASK) | ISMT_SPGT_SPD_80K),
+			priv->smba + ISMT_SPGT);
+		break;
+
+	case 100:
+		dev_dbg(dev, "Setting SMBus clock to 100 kHz\n");
+		writel(((val & ~ISMT_SPGT_SPD_MASK) | ISMT_SPGT_SPD_100K),
+			priv->smba + ISMT_SPGT);
+		break;
+
+	case 400:
+		dev_dbg(dev, "Setting SMBus clock to 400 kHz\n");
+		writel(((val & ~ISMT_SPGT_SPD_MASK) | ISMT_SPGT_SPD_400K),
+			priv->smba + ISMT_SPGT);
+		break;
+
+	case 1000:
+		dev_dbg(dev, "Setting SMBus clock to 1000 kHz\n");
+		writel(((val & ~ISMT_SPGT_SPD_MASK) | ISMT_SPGT_SPD_1M),
+			priv->smba + ISMT_SPGT);
+		break;
+
+	default:
+		dev_warn(dev, "Invalid SMBus clock speed, only 0, 80, 100, 400, and 1000 are valid\n");
+		break;
+	}
+
+	val = readl(priv->smba + ISMT_SPGT);
+
+	switch (val & ISMT_SPGT_SPD_MASK) {
+	case ISMT_SPGT_SPD_80K:
+		bus_speed = 80;
+		break;
+	case ISMT_SPGT_SPD_100K:
+		bus_speed = 100;
+		break;
+	case ISMT_SPGT_SPD_400K:
+		bus_speed = 400;
+		break;
+	case ISMT_SPGT_SPD_1M:
+		bus_speed = 1000;
+		break;
+	}
+	dev_dbg(dev, "SMBus clock is running at %d kHz\n", bus_speed);
+}
+
+/**
+ * ismt_dev_init() - initialize the iSMT data structures
+ * @priv: iSMT private data
+ */
+static int ismt_dev_init(struct ismt_priv *priv)
+{
+	/* allocate memory for the descriptor */
+	priv->hw = dmam_alloc_coherent(&priv->pci_dev->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;
+	init_completion(&priv->cmp);
+
+	return 0;
+}
+
+/**
+ * ismt_int_init() - initialize interrupts
+ * @priv: iSMT private data
+ */
+static int ismt_int_init(struct ismt_priv *priv)
+{
+	int err;
+
+	/* Try using MSI interrupts */
+	err = pci_enable_msi(priv->pci_dev);
+	if (err) {
+		dev_warn(&priv->pci_dev->dev,
+			 "Unable to use MSI interrupts, falling back to legacy\n");
+		goto intx;
+	}
+
+	err = devm_request_irq(&priv->pci_dev->dev,
+			       priv->pci_dev->irq,
+			       ismt_do_msi_interrupt,
+			       0,
+			       "ismt-msi",
+			       priv);
+	if (err) {
+		pci_disable_msi(priv->pci_dev);
+		goto intx;
+	}
+
+	priv->using_msi = true;
+	goto done;
+
+	/* Try using legacy interrupts */
+intx:
+	err = devm_request_irq(&priv->pci_dev->dev,
+			       priv->pci_dev->irq,
+			       ismt_do_interrupt,
+			       IRQF_SHARED,
+			       "ismt-intx",
+			       priv);
+	if (err) {
+		dev_err(&priv->pci_dev->dev, "no usable interrupts\n");
+		return -ENODEV;
+	}
+
+	priv->using_msi = false;
+
+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
+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;
+
+	/* 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;
+
+	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);
+	len = pci_resource_len(pdev, SMBBAR);
+	if (!start || !len) {
+		dev_err(&pdev->dev,
+			"SMBus base address uninitialized, upgrade BIOS\n");
+		return -ENODEV;
+	}
+
+	snprintf(priv->adapter.name, sizeof(priv->adapter.name),
+		 "SMBus iSMT adapter at %lx", start);
+
+	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;
+	}
+
+	if ((pci_set_dma_mask(pdev, DMA_BIT_MASK(64)) != 0) ||
+	    (pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64)) != 0)) {
+		if ((pci_set_dma_mask(pdev, DMA_BIT_MASK(32)) != 0) ||
+		    (pci_set_consistent_dma_mask(pdev,
+						 DMA_BIT_MASK(32)) != 0)) {
+			dev_err(&pdev->dev, "pci_set_dma_mask fail %p\n",
+				pdev);
+			goto fail;
+		}
+	}
+
+	err = ismt_dev_init(priv);
+	if (err)
+		goto fail;
+
+	ismt_hw_init(priv);
+
+	err = ismt_int_init(priv);
+	if (err)
+		goto fail;
+
+	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 ismt_remove(struct pci_dev *pdev)
+{
+	struct ismt_priv *priv = pci_get_drvdata(pdev);
+
+	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 = ismt_remove,
+	.suspend = ismt_suspend,
+	.resume = ismt_resume,
+};
+
+module_pci_driver(ismt_driver);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Bill E. Brown <bill.e.brown@intel.com>");
+MODULE_DESCRIPTION("Intel SMBus Message Transport (iSMT) driver");