[v3,03/10] drivers/peci: Add support for PECI bus driver core

Message ID 20180410183212.16787-4-jae.hyun.yoo@linux.intel.com
State Not Applicable, archived
Headers show
Series
  • PECI device driver introduction
Related show

Commit Message

Jae Hyun Yoo April 10, 2018, 6:32 p.m.
This commit adds driver implementation for PECI bus core into linux
driver framework.

Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Haiyue Wang <haiyue.wang@linux.intel.com>
Reviewed-by: James Feist <james.feist@linux.intel.com>
Reviewed-by: Vernon Mauery <vernon.mauery@linux.intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Andrew Jeffery <andrew@aj.id.au>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jason M Biils <jason.m.bills@linux.intel.com>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Julia Cartwright <juliac@eso.teric.us>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Milton Miller II <miltonm@us.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stef van Os <stef.van.os@prodrive-technologies.com>
Cc: Sumeet R Pawnikar <sumeet.r.pawnikar@intel.com>
---
 drivers/Kconfig                 |    2 +
 drivers/Makefile                |    1 +
 drivers/peci/Kconfig            |   17 +
 drivers/peci/Makefile           |    6 +
 drivers/peci/peci-core.c        | 1291 +++++++++++++++++++++++++++++++++++++++
 include/linux/peci.h            |  107 ++++
 include/uapi/linux/peci-ioctl.h |  200 ++++++
 7 files changed, 1624 insertions(+)
 create mode 100644 drivers/peci/Kconfig
 create mode 100644 drivers/peci/Makefile
 create mode 100644 drivers/peci/peci-core.c
 create mode 100644 include/linux/peci.h
 create mode 100644 include/uapi/linux/peci-ioctl.h

Comments

kbuild test robot April 19, 2018, 6:59 p.m. | #1
Hi Jae,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.17-rc1 next-20180419]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Jae-Hyun-Yoo/PECI-device-driver-introduction/20180411-180018
config: x86_64-randconfig-s0-04192349 (attached as .config)
compiler: gcc-6 (Debian 6.4.0-9) 6.4.0 20171026
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   drivers//peci/peci-core.c: In function 'peci_device_match':
>> drivers//peci/peci-core.c:739:6: error: implicit declaration of function 'peci_of_match_device' [-Werror=implicit-function-declaration]
     if (peci_of_match_device(drv->of_match_table, client))
         ^~~~~~~~~~~~~~~~~~~~
   At top level:
   drivers//peci/peci-core.c:840:28: warning: 'peci_new_device' defined but not used [-Wunused-function]
    static struct peci_client *peci_new_device(struct peci_adapter *adapter,
                               ^~~~~~~~~~~~~~~
   drivers//peci/peci-core.c:135:29: warning: 'peci_verify_adapter' defined but not used [-Wunused-function]
    static struct peci_adapter *peci_verify_adapter(struct device *dev)
                                ^~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +/peci_of_match_device +739 drivers//peci/peci-core.c

   732	
   733	static int peci_device_match(struct device *dev, struct device_driver *drv)
   734	{
   735		struct peci_client *client = peci_verify_client(dev);
   736		struct peci_driver *driver;
   737	
   738		/* Attempt an OF style match */
 > 739		if (peci_of_match_device(drv->of_match_table, client))
   740			return 1;
   741	
   742		driver = to_peci_driver(drv);
   743	
   744		if (peci_match_id(driver->id_table, client))
   745			return 1;
   746	
   747		return 0;
   748	}
   749	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
Greg KH April 23, 2018, 10:52 a.m. | #2
On Tue, Apr 10, 2018 at 11:32:05AM -0700, Jae Hyun Yoo wrote:
> +static void peci_adapter_dev_release(struct device *dev)
> +{
> +	/* do nothing */
> +}

As per the in-kernel documentation, I am now allowed to make fun of you.

You are trying to "out smart" the kernel by getting rid of a warning
message that was explicitly put there for you to do something.  To think
that by just providing an "empty" function you are somehow fulfilling
the API requirement is quite bold, don't you think?

This has to be fixed.  I didn't put that warning in there for no good
reason.  Please go read the documentation again...

greg k-h
Jae Hyun Yoo April 23, 2018, 5:40 p.m. | #3
On 4/23/2018 3:52 AM, Greg KH wrote:
> On Tue, Apr 10, 2018 at 11:32:05AM -0700, Jae Hyun Yoo wrote:
>> +static void peci_adapter_dev_release(struct device *dev)
>> +{
>> +	/* do nothing */
>> +}
> 
> As per the in-kernel documentation, I am now allowed to make fun of you.
> 
> You are trying to "out smart" the kernel by getting rid of a warning
> message that was explicitly put there for you to do something.  To think
> that by just providing an "empty" function you are somehow fulfilling
> the API requirement is quite bold, don't you think?
> 
> This has to be fixed.  I didn't put that warning in there for no good
> reason.  Please go read the documentation again...
> 
> greg k-h
> 

Hi Greg,

Thanks a lot for your review.

I think, it should contain actual device resource release code which is
being done by peci_del_adapter(), or a coupling logic should be added
between peci_adapter_dev_release() and peci_del_adapter().

As you suggested, I'll check it again after reading documentation and
understanding core.c code more deeply.

Jae
Andy Shevchenko April 24, 2018, 4:01 p.m. | #4
On Tue, 2018-04-10 at 11:32 -0700, Jae Hyun Yoo wrote:
> This commit adds driver implementation for PECI bus core into linux
> driver framework.
> 

All comments you got for patch 6 are applicable here.

And perhaps in the rest of the series.

The rule of thumb: when you get even single comment in a certain place,
re-check _entire_ series for the same / similar patterns!
Jae Hyun Yoo April 24, 2018, 4:29 p.m. | #5
On 4/24/2018 9:01 AM, Andy Shevchenko wrote:
> On Tue, 2018-04-10 at 11:32 -0700, Jae Hyun Yoo wrote:
>> This commit adds driver implementation for PECI bus core into linux
>> driver framework.
>>
> 
> All comments you got for patch 6 are applicable here.
> 
> And perhaps in the rest of the series.
> 
> The rule of thumb: when you get even single comment in a certain place,
> re-check _entire_ series for the same / similar patterns!
> 

Thanks for your advice. I'll keep that in mind.

Jae

Patch

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 95b9ccc08165..8c44d9738377 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -217,4 +217,6 @@  source "drivers/siox/Kconfig"
 
 source "drivers/slimbus/Kconfig"
 
+source "drivers/peci/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 24cd47014657..250fe3d0fa7e 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -185,3 +185,4 @@  obj-$(CONFIG_TEE)		+= tee/
 obj-$(CONFIG_MULTIPLEXER)	+= mux/
 obj-$(CONFIG_UNISYS_VISORBUS)	+= visorbus/
 obj-$(CONFIG_SIOX)		+= siox/
+obj-$(CONFIG_PECI)		+= peci/
diff --git a/drivers/peci/Kconfig b/drivers/peci/Kconfig
new file mode 100644
index 000000000000..1fbc13f9e6c2
--- /dev/null
+++ b/drivers/peci/Kconfig
@@ -0,0 +1,17 @@ 
+#
+# Platform Environment Control Interface (PECI) subsystem configuration
+#
+
+menu "PECI support"
+
+config PECI
+	bool "PECI support"
+	select RT_MUTEXES
+	select CRC8
+	help
+	  The Platform Environment Control Interface (PECI) is a one-wire bus
+	  interface that provides a communication channel between Intel
+	  processors and chipset components to external monitoring or control
+	  devices.
+
+endmenu
diff --git a/drivers/peci/Makefile b/drivers/peci/Makefile
new file mode 100644
index 000000000000..9e8615e0d3ff
--- /dev/null
+++ b/drivers/peci/Makefile
@@ -0,0 +1,6 @@ 
+#
+# Makefile for the PECI core and bus drivers.
+#
+
+# Core functionality
+obj-$(CONFIG_PECI)		+= peci-core.o
diff --git a/drivers/peci/peci-core.c b/drivers/peci/peci-core.c
new file mode 100644
index 000000000000..9b45869b7c39
--- /dev/null
+++ b/drivers/peci/peci-core.c
@@ -0,0 +1,1291 @@ 
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Intel Corporation
+
+#include <linux/crc8.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/peci.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+/* Device Specific Completion Code (CC) Definition */
+#define DEV_PECI_CC_SUCCESS          0x40
+#define DEV_PECI_CC_TIMEOUT          0x80
+#define DEV_PECI_CC_OUT_OF_RESOURCE  0x81
+#define DEV_PECI_CC_UNAVAIL_RESOURCE 0x82
+#define DEV_PECI_CC_INVALID_REQ      0x90
+
+/* Completion Code mask to check retry needs */
+#define DEV_PECI_CC_RETRY_CHECK_MASK 0xf0
+#define DEV_PECI_CC_NEED_RETRY       0x80
+
+/* Skylake EDS says to retry for 250ms */
+#define DEV_PECI_RETRY_TIME_MS     250
+#define DEV_PECI_RETRY_INTERVAL_MS 10
+#define DEV_PECI_RETRY_BIT         0x01
+
+#define GET_TEMP_WR_LEN   1
+#define GET_TEMP_RD_LEN   2
+#define GET_TEMP_PECI_CMD 0x01
+
+#define GET_DIB_WR_LEN   1
+#define GET_DIB_RD_LEN   8
+#define GET_DIB_PECI_CMD 0xf7
+
+#define RDPKGCFG_WRITE_LEN     5
+#define RDPKGCFG_READ_LEN_BASE 1
+#define RDPKGCFG_PECI_CMD      0xa1
+
+#define WRPKGCFG_WRITE_LEN_BASE 6
+#define WRPKGCFG_READ_LEN       1
+#define WRPKGCFG_PECI_CMD       0xa5
+
+#define RDIAMSR_WRITE_LEN 5
+#define RDIAMSR_READ_LEN  9
+#define RDIAMSR_PECI_CMD  0xb1
+
+#define WRIAMSR_PECI_CMD  0xb5
+
+#define RDPCICFG_WRITE_LEN 6
+#define RDPCICFG_READ_LEN  5
+#define RDPCICFG_PECI_CMD  0x61
+
+#define WRPCICFG_PECI_CMD  0x65
+
+#define RDPCICFGLOCAL_WRITE_LEN     5
+#define RDPCICFGLOCAL_READ_LEN_BASE 1
+#define RDPCICFGLOCAL_PECI_CMD      0xe1
+
+#define WRPCICFGLOCAL_WRITE_LEN_BASE 6
+#define WRPCICFGLOCAL_READ_LEN       1
+#define WRPCICFGLOCAL_PECI_CMD       0xe5
+
+/* Macro for getting minor revision number from DIB */
+#define GET_MINOR_REV_NUM(x) (((x) >> 8) & 0xF)
+
+/* CRC8 table for Assure Write Frame Check */
+#define PECI_CRC8_POLYNOMIAL 0x07
+DECLARE_CRC8_TABLE(peci_crc8_table);
+
+static struct device_type peci_adapter_type;
+static struct device_type peci_client_type;
+
+/* Max number of peci cdev */
+#define PECI_CDEV_MAX    16
+
+/* Max index of devices sharing the same client address */
+#define PECI_DEV_IDX_MAX 16
+
+static dev_t peci_devt;
+static bool is_registered;
+
+static DEFINE_MUTEX(core_lock);
+static DEFINE_IDR(peci_adapter_idr);
+
+static ssize_t name_show(struct device *dev,
+			 struct device_attribute *attr,
+			 char *buf)
+{
+	return sprintf(buf, "%s\n", dev->type == &peci_client_type ?
+		       to_peci_client(dev)->name : to_peci_adapter(dev)->name);
+}
+static DEVICE_ATTR_RO(name);
+
+static void peci_client_dev_release(struct device *dev)
+{
+	kfree(to_peci_client(dev));
+}
+
+static struct attribute *peci_device_attrs[] = {
+	&dev_attr_name.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(peci_device);
+
+static struct device_type peci_client_type = {
+	.groups		= peci_device_groups,
+	.release	= peci_client_dev_release,
+};
+
+static struct peci_client *peci_verify_client(struct device *dev)
+{
+	return (dev->type == &peci_client_type)
+			? to_peci_client(dev)
+			: NULL;
+}
+
+static void peci_adapter_dev_release(struct device *dev)
+{
+	/* do nothing */
+}
+
+static struct attribute *peci_adapter_attrs[] = {
+	&dev_attr_name.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(peci_adapter);
+
+static struct device_type peci_adapter_type = {
+	.groups		= peci_adapter_groups,
+	.release	= peci_adapter_dev_release,
+};
+
+static struct peci_adapter *peci_verify_adapter(struct device *dev)
+{
+	return (dev->type == &peci_adapter_type)
+			? to_peci_adapter(dev)
+			: NULL;
+}
+
+static struct peci_adapter *peci_get_adapter(int nr)
+{
+	struct peci_adapter *adapter;
+
+	mutex_lock(&core_lock);
+	adapter = idr_find(&peci_adapter_idr, nr);
+	if (!adapter)
+		goto out_unlock;
+
+	if (try_module_get(adapter->owner))
+		get_device(&adapter->dev);
+	else
+		adapter = NULL;
+
+out_unlock:
+	mutex_unlock(&core_lock);
+	return adapter;
+}
+
+static void peci_put_adapter(struct peci_adapter *adapter)
+{
+	if (!adapter)
+		return;
+
+	put_device(&adapter->dev);
+	module_put(adapter->owner);
+}
+
+static u8 peci_aw_fcs(u8 *data, int len)
+{
+	return crc8(peci_crc8_table, data, (size_t)len, 0);
+}
+
+static int __peci_xfer(struct peci_adapter *adapter, struct peci_xfer_msg *msg,
+		       bool do_retry, bool has_aw_fcs)
+{
+	ktime_t start, end;
+	s64 elapsed_ms;
+	int rc = 0;
+
+	/**
+	 * For some commands, the PECI originator may need to retry a command if
+	 * the processor PECI client responds with a 0x8x completion code. In
+	 * each instance, the processor PECI client may have started the
+	 * operation but not completed it yet. When the 'retry' bit is set, the
+	 * PECI client will ignore a new request if it exactly matches a
+	 * previous valid request.
+	 */
+
+	if (do_retry)
+		start = ktime_get();
+
+	do {
+		rc = adapter->xfer(adapter, msg);
+
+		if (!do_retry || rc)
+			break;
+
+		if (msg->rx_buf[0] == DEV_PECI_CC_SUCCESS)
+			break;
+
+		/* Retry is needed when completion code is 0x8x */
+		if ((msg->rx_buf[0] & DEV_PECI_CC_RETRY_CHECK_MASK) !=
+		    DEV_PECI_CC_NEED_RETRY) {
+			rc = -EIO;
+			break;
+		}
+
+		/* Set the retry bit to indicate a retry attempt */
+		msg->tx_buf[1] |= DEV_PECI_RETRY_BIT;
+
+		/* Recalculate the AW FCS if it has one */
+		if (has_aw_fcs)
+			msg->tx_buf[msg->tx_len - 1] = 0x80 ^
+						peci_aw_fcs((u8 *)msg,
+							    2 + msg->tx_len);
+
+		/**
+		 * Retry for at least 250ms before returning an error.
+		 * Retry interval guideline:
+		 *   No minimum < Retry Interval < No maximum
+		 *                (recommend 10ms)
+		 */
+		end = ktime_get();
+		elapsed_ms = ktime_to_ms(ktime_sub(end, start));
+		if (elapsed_ms >= DEV_PECI_RETRY_TIME_MS) {
+			dev_dbg(&adapter->dev, "Timeout retrying xfer!\n");
+			rc = -ETIMEDOUT;
+			break;
+		}
+
+		usleep_range(DEV_PECI_RETRY_INTERVAL_MS * 1000,
+			     (DEV_PECI_RETRY_INTERVAL_MS * 1000) + 1000);
+	} while (true);
+
+	if (rc)
+		dev_dbg(&adapter->dev, "xfer error, rc: %d\n", rc);
+
+	return rc;
+}
+
+static int peci_xfer(struct peci_adapter *adapter, struct peci_xfer_msg *msg)
+{
+	return __peci_xfer(adapter, msg, false, false);
+}
+
+static int peci_xfer_with_retries(struct peci_adapter *adapter,
+				  struct peci_xfer_msg *msg,
+				  bool has_aw_fcs)
+{
+	return __peci_xfer(adapter, msg, true, has_aw_fcs);
+}
+
+static int peci_scan_cmd_mask(struct peci_adapter *adapter)
+{
+	struct peci_xfer_msg msg;
+	int rc = 0;
+	u32 dib;
+
+	/* Update command mask just once */
+	if (adapter->cmd_mask & BIT(PECI_CMD_PING))
+		return 0;
+
+	msg.addr      = PECI_BASE_ADDR;
+	msg.tx_len    = GET_DIB_WR_LEN;
+	msg.rx_len    = GET_DIB_RD_LEN;
+	msg.tx_buf[0] = GET_DIB_PECI_CMD;
+
+	rc = peci_xfer(adapter, &msg);
+	if (rc)
+		return rc;
+
+	dib = msg.rx_buf[0] | (msg.rx_buf[1] << 8) |
+	      (msg.rx_buf[2] << 16) | (msg.rx_buf[3] << 24);
+
+	/* Check special case for Get DIB command */
+	if (dib == 0x00) {
+		dev_dbg(&adapter->dev, "DIB read as 0x00\n");
+		return -EIO;
+	}
+
+	/**
+	 * Setting up the supporting commands based on minor revision number.
+	 * See PECI Spec Table 3-1.
+	 */
+	switch (GET_MINOR_REV_NUM(dib)) {
+	case 6:
+		adapter->cmd_mask |= BIT(PECI_CMD_WR_IA_MSR);
+		/* fallthrough */
+	case 5:
+		adapter->cmd_mask |= BIT(PECI_CMD_WR_PCI_CFG);
+		/* fallthrough */
+	case 4:
+		adapter->cmd_mask |= BIT(PECI_CMD_RD_PCI_CFG);
+		/* fallthrough */
+	case 3:
+		adapter->cmd_mask |= BIT(PECI_CMD_RD_PCI_CFG_LOCAL);
+		adapter->cmd_mask |= BIT(PECI_CMD_WR_PCI_CFG_LOCAL);
+		/* fallthrough */
+	case 2:
+		adapter->cmd_mask |= BIT(PECI_CMD_RD_IA_MSR);
+		/* fallthrough */
+	case 1:
+		adapter->cmd_mask |= BIT(PECI_CMD_RD_PKG_CFG);
+		adapter->cmd_mask |= BIT(PECI_CMD_WR_PKG_CFG);
+	}
+
+	adapter->cmd_mask |= BIT(PECI_CMD_GET_TEMP);
+	adapter->cmd_mask |= BIT(PECI_CMD_GET_DIB);
+	adapter->cmd_mask |= BIT(PECI_CMD_PING);
+
+	return rc;
+}
+
+static int peci_cmd_support(struct peci_adapter *adapter, enum peci_cmd cmd)
+{
+	if (!(adapter->cmd_mask & BIT(PECI_CMD_PING)) &&
+	    peci_scan_cmd_mask(adapter) < 0) {
+		dev_dbg(&adapter->dev, "Failed to scan command mask\n");
+		return -EIO;
+	}
+
+	if (!(adapter->cmd_mask & BIT(cmd))) {
+		dev_dbg(&adapter->dev, "Command %d is not supported\n", cmd);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int peci_ioctl_ping(struct peci_adapter *adapter, void *vmsg)
+{
+	struct peci_ping_msg *umsg = vmsg;
+	struct peci_xfer_msg msg;
+
+	msg.addr   = umsg->addr;
+	msg.tx_len = 0;
+	msg.rx_len = 0;
+
+	return peci_xfer(adapter, &msg);
+}
+
+static int peci_ioctl_get_dib(struct peci_adapter *adapter, void *vmsg)
+{
+	struct peci_get_dib_msg *umsg = vmsg;
+	struct peci_xfer_msg msg;
+	int rc;
+
+	msg.addr      = umsg->addr;
+	msg.tx_len    = GET_DIB_WR_LEN;
+	msg.rx_len    = GET_DIB_RD_LEN;
+	msg.tx_buf[0] = GET_DIB_PECI_CMD;
+
+	rc = peci_xfer(adapter, &msg);
+	if (rc)
+		return rc;
+
+	umsg->dib = msg.rx_buf[0] | (msg.rx_buf[1] << 8) |
+		     (msg.rx_buf[2] << 16) | (msg.rx_buf[3] << 24);
+
+	return 0;
+}
+
+static int peci_ioctl_get_temp(struct peci_adapter *adapter, void *vmsg)
+{
+	struct peci_get_temp_msg *umsg = vmsg;
+	struct peci_xfer_msg msg;
+	int rc;
+
+	msg.addr      = umsg->addr;
+	msg.tx_len    = GET_TEMP_WR_LEN;
+	msg.rx_len    = GET_TEMP_RD_LEN;
+	msg.tx_buf[0] = GET_TEMP_PECI_CMD;
+
+	rc = peci_xfer(adapter, &msg);
+	if (rc)
+		return rc;
+
+	umsg->temp_raw = msg.rx_buf[0] | (msg.rx_buf[1] << 8);
+
+	return 0;
+}
+
+static int peci_ioctl_rd_pkg_cfg(struct peci_adapter *adapter, void *vmsg)
+{
+	struct peci_rd_pkg_cfg_msg *umsg = vmsg;
+	struct peci_xfer_msg msg;
+	int rc = 0;
+
+	/* Per the PECI spec, the read length must be a byte, word, or dword */
+	if (umsg->rx_len != 1 && umsg->rx_len != 2 && umsg->rx_len != 4) {
+		dev_dbg(&adapter->dev, "Invalid read length, rx_len: %d\n",
+			umsg->rx_len);
+		return -EINVAL;
+	}
+
+	msg.addr = umsg->addr;
+	msg.tx_len = RDPKGCFG_WRITE_LEN;
+	/* read lengths of 1 and 2 result in an error, so only use 4 for now */
+	msg.rx_len = RDPKGCFG_READ_LEN_BASE + umsg->rx_len;
+	msg.tx_buf[0] = RDPKGCFG_PECI_CMD;
+	msg.tx_buf[1] = 0x00;         /* request byte for Host ID | Retry bit */
+				      /* Host ID is 0 for PECI 3.0 */
+	msg.tx_buf[2] = umsg->index;            /* RdPkgConfig index */
+	msg.tx_buf[3] = (u8)umsg->param;        /* LSB - Config parameter */
+	msg.tx_buf[4] = (u8)(umsg->param >> 8); /* MSB - Config parameter */
+
+	rc = peci_xfer_with_retries(adapter, &msg, false);
+	if (!rc)
+		memcpy(umsg->pkg_config, &msg.rx_buf[1], umsg->rx_len);
+
+	return rc;
+}
+
+static int peci_ioctl_wr_pkg_cfg(struct peci_adapter *adapter, void *vmsg)
+{
+	struct peci_wr_pkg_cfg_msg *umsg = vmsg;
+	struct peci_xfer_msg msg;
+	int rc = 0, i;
+
+	/* Per the PECI spec, the write length must be a dword */
+	if (umsg->tx_len != 4) {
+		dev_dbg(&adapter->dev, "Invalid write length, tx_len: %d\n",
+			umsg->tx_len);
+		return -EINVAL;
+	}
+
+	msg.addr = umsg->addr;
+	msg.tx_len = WRPKGCFG_WRITE_LEN_BASE + umsg->tx_len;
+	/* read lengths of 1 and 2 result in an error, so only use 4 for now */
+	msg.rx_len = WRPKGCFG_READ_LEN;
+	msg.tx_buf[0] = WRPKGCFG_PECI_CMD;
+	msg.tx_buf[1] = 0x00;         /* request byte for Host ID | Retry bit */
+				      /* Host ID is 0 for PECI 3.0 */
+	msg.tx_buf[2] = umsg->index;            /* RdPkgConfig index */
+	msg.tx_buf[3] = (u8)umsg->param;        /* LSB - Config parameter */
+	msg.tx_buf[4] = (u8)(umsg->param >> 8); /* MSB - Config parameter */
+	for (i = 0; i < umsg->tx_len; i++)
+		msg.tx_buf[5 + i] = (u8)(umsg->value >> (i << 3));
+
+	/* Add an Assure Write Frame Check Sequence byte */
+	msg.tx_buf[5 + i] = 0x80 ^
+			    peci_aw_fcs((u8 *)&msg, 8 + umsg->tx_len);
+
+	rc = peci_xfer_with_retries(adapter, &msg, true);
+
+	return rc;
+}
+
+static int peci_ioctl_rd_ia_msr(struct peci_adapter *adapter, void *vmsg)
+{
+	struct peci_rd_ia_msr_msg *umsg = vmsg;
+	struct peci_xfer_msg msg;
+	int rc = 0;
+
+	msg.addr = umsg->addr;
+	msg.tx_len = RDIAMSR_WRITE_LEN;
+	msg.rx_len = RDIAMSR_READ_LEN;
+	msg.tx_buf[0] = RDIAMSR_PECI_CMD;
+	msg.tx_buf[1] = 0x00;
+	msg.tx_buf[2] = umsg->thread_id;
+	msg.tx_buf[3] = (u8)umsg->address;
+	msg.tx_buf[4] = (u8)(umsg->address >> 8);
+
+	rc = peci_xfer_with_retries(adapter, &msg, false);
+	if (!rc)
+		memcpy(&umsg->value, &msg.rx_buf[1], sizeof(uint64_t));
+
+	return rc;
+}
+
+static int peci_ioctl_rd_pci_cfg(struct peci_adapter *adapter, void *vmsg)
+{
+	struct peci_rd_pci_cfg_msg *umsg = vmsg;
+	struct peci_xfer_msg msg;
+	u32 address;
+	int rc = 0;
+
+	address = umsg->reg;                  /* [11:0]  - Register */
+	address |= (u32)umsg->function << 12; /* [14:12] - Function */
+	address |= (u32)umsg->device << 15;   /* [19:15] - Device   */
+	address |= (u32)umsg->bus << 20;      /* [27:20] - Bus      */
+					      /* [31:28] - Reserved */
+	msg.addr = umsg->addr;
+	msg.tx_len = RDPCICFG_WRITE_LEN;
+	msg.rx_len = RDPCICFG_READ_LEN;
+	msg.tx_buf[0] = RDPCICFG_PECI_CMD;
+	msg.tx_buf[1] = 0x00;         /* request byte for Host ID | Retry bit */
+				      /* Host ID is 0 for PECI 3.0 */
+	msg.tx_buf[2] = (u8)address;         /* LSB - PCI Config Address */
+	msg.tx_buf[3] = (u8)(address >> 8);  /* PCI Config Address */
+	msg.tx_buf[4] = (u8)(address >> 16); /* PCI Config Address */
+	msg.tx_buf[5] = (u8)(address >> 24); /* MSB - PCI Config Address */
+
+	rc = peci_xfer_with_retries(adapter, &msg, false);
+	if (!rc)
+		memcpy(umsg->pci_config, &msg.rx_buf[1], 4);
+
+	return rc;
+}
+
+static int peci_ioctl_rd_pci_cfg_local(struct peci_adapter *adapter, void *vmsg)
+{
+	struct peci_rd_pci_cfg_local_msg *umsg = vmsg;
+	struct peci_xfer_msg msg;
+	u32 address;
+	int rc = 0;
+
+	/* Per the PECI spec, the read length must be a byte, word, or dword */
+	if (umsg->rx_len != 1 && umsg->rx_len != 2 && umsg->rx_len != 4) {
+		dev_dbg(&adapter->dev, "Invalid read length, rx_len: %d\n",
+			umsg->rx_len);
+		return -EINVAL;
+	}
+
+	address = umsg->reg;                  /* [11:0]  - Register */
+	address |= (u32)umsg->function << 12; /* [14:12] - Function */
+	address |= (u32)umsg->device << 15;   /* [19:15] - Device   */
+	address |= (u32)umsg->bus << 20;      /* [23:20] - Bus      */
+
+	msg.addr = umsg->addr;
+	msg.tx_len = RDPCICFGLOCAL_WRITE_LEN;
+	msg.rx_len = RDPCICFGLOCAL_READ_LEN_BASE + umsg->rx_len;
+	msg.tx_buf[0] = RDPCICFGLOCAL_PECI_CMD;
+	msg.tx_buf[1] = 0x00;         /* request byte for Host ID | Retry bit */
+				      /* Host ID is 0 for PECI 3.0 */
+	msg.tx_buf[2] = (u8)address;       /* LSB - PCI Configuration Address */
+	msg.tx_buf[3] = (u8)(address >> 8);  /* PCI Configuration Address */
+	msg.tx_buf[4] = (u8)(address >> 16); /* PCI Configuration Address */
+
+	rc = peci_xfer_with_retries(adapter, &msg, false);
+	if (!rc)
+		memcpy(umsg->pci_config, &msg.rx_buf[1], umsg->rx_len);
+
+	return rc;
+}
+
+static int peci_ioctl_wr_pci_cfg_local(struct peci_adapter *adapter, void *vmsg)
+{
+	struct peci_wr_pci_cfg_local_msg *umsg = vmsg;
+	struct peci_xfer_msg msg;
+	int rc = 0, i;
+	u32 address;
+
+	/* Per the PECI spec, the write length must be a byte, word, or dword */
+	if (umsg->tx_len != 1 && umsg->tx_len != 2 && umsg->tx_len != 4) {
+		dev_dbg(&adapter->dev, "Invalid write length, tx_len: %d\n",
+			umsg->tx_len);
+		return -EINVAL;
+	}
+
+	address = umsg->reg;                  /* [11:0]  - Register */
+	address |= (u32)umsg->function << 12; /* [14:12] - Function */
+	address |= (u32)umsg->device << 15;   /* [19:15] - Device   */
+	address |= (u32)umsg->bus << 20;      /* [23:20] - Bus      */
+
+	msg.addr = umsg->addr;
+	msg.tx_len = WRPCICFGLOCAL_WRITE_LEN_BASE + umsg->tx_len;
+	msg.rx_len = WRPCICFGLOCAL_READ_LEN;
+	msg.tx_buf[0] = WRPCICFGLOCAL_PECI_CMD;
+	msg.tx_buf[1] = 0x00;         /* request byte for Host ID | Retry bit */
+				      /* Host ID is 0 for PECI 3.0 */
+	msg.tx_buf[2] = (u8)address;       /* LSB - PCI Configuration Address */
+	msg.tx_buf[3] = (u8)(address >> 8);  /* PCI Configuration Address */
+	msg.tx_buf[4] = (u8)(address >> 16); /* PCI Configuration Address */
+	for (i = 0; i < umsg->tx_len; i++)
+		msg.tx_buf[5 + i] = (u8)(umsg->value >> (i << 3));
+
+	/* Add an Assure Write Frame Check Sequence byte */
+	msg.tx_buf[5 + i] = 0x80 ^
+			    peci_aw_fcs((u8 *)&msg, 8 + umsg->tx_len);
+
+	rc = peci_xfer_with_retries(adapter, &msg, true);
+
+	return rc;
+}
+
+typedef int (*peci_ioctl_fn_type)(struct peci_adapter *, void *);
+
+static const peci_ioctl_fn_type peci_ioctl_fn[PECI_CMD_MAX] = {
+	NULL, /* Reserved */
+	peci_ioctl_ping,
+	peci_ioctl_get_dib,
+	peci_ioctl_get_temp,
+	peci_ioctl_rd_pkg_cfg,
+	peci_ioctl_wr_pkg_cfg,
+	peci_ioctl_rd_ia_msr,
+	NULL, /* Reserved */
+	peci_ioctl_rd_pci_cfg,
+	NULL, /* Reserved */
+	peci_ioctl_rd_pci_cfg_local,
+	peci_ioctl_wr_pci_cfg_local,
+};
+
+int peci_command(struct peci_adapter *adapter, enum peci_cmd cmd, void *vmsg)
+{
+	int rc = 0;
+
+	if (cmd >= PECI_CMD_MAX || cmd < PECI_CMD_XFER)
+		return -EINVAL;
+
+	dev_dbg(&adapter->dev, "%s, cmd=0x%02x\n", __func__, cmd);
+
+	if (!peci_ioctl_fn[cmd])
+		return -EINVAL;
+
+	rt_mutex_lock(&adapter->bus_lock);
+
+	rc = peci_cmd_support(adapter, cmd);
+	if (!rc)
+		rc = peci_ioctl_fn[cmd](adapter, vmsg);
+
+	rt_mutex_unlock(&adapter->bus_lock);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(peci_command);
+
+static long peci_ioctl(struct file *file, unsigned int iocmd, unsigned long arg)
+{
+	struct peci_adapter *adapter = file->private_data;
+	void __user *argp = (void __user *)arg;
+	unsigned int msg_len;
+	enum peci_cmd cmd;
+	int rc = 0;
+	u8 *msg;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	dev_dbg(&adapter->dev, "ioctl, cmd=0x%x, arg=0x%lx\n", iocmd, arg);
+
+	switch (iocmd) {
+	case PECI_IOC_PING:
+	case PECI_IOC_GET_DIB:
+	case PECI_IOC_GET_TEMP:
+	case PECI_IOC_RD_PKG_CFG:
+	case PECI_IOC_WR_PKG_CFG:
+	case PECI_IOC_RD_IA_MSR:
+	case PECI_IOC_RD_PCI_CFG:
+	case PECI_IOC_RD_PCI_CFG_LOCAL:
+	case PECI_IOC_WR_PCI_CFG_LOCAL:
+		cmd = _IOC_NR(iocmd);
+		msg_len = _IOC_SIZE(iocmd);
+		break;
+
+	default:
+		dev_dbg(&adapter->dev, "Invalid ioctl cmd : 0x%x\n", iocmd);
+		return -ENOTTY;
+	}
+
+	msg = memdup_user(argp, msg_len);
+	if (IS_ERR(msg))
+		return PTR_ERR(msg);
+
+	rc = peci_command(adapter, cmd, msg);
+
+	if (!rc && copy_to_user(argp, msg, msg_len))
+		rc = -EFAULT;
+
+	kfree(msg);
+	return (long)rc;
+}
+
+static int peci_open(struct inode *inode, struct file *file)
+{
+	unsigned int minor = iminor(inode);
+	struct peci_adapter *adapter;
+
+	adapter = peci_get_adapter(minor);
+	if (!adapter)
+		return -ENODEV;
+
+	file->private_data = adapter;
+
+	return 0;
+}
+
+static int peci_release(struct inode *inode, struct file *file)
+{
+	struct peci_adapter *adapter = file->private_data;
+
+	peci_put_adapter(adapter);
+	file->private_data = NULL;
+
+	return 0;
+}
+
+static const struct file_operations peci_fops = {
+	.owner          = THIS_MODULE,
+	.unlocked_ioctl = peci_ioctl,
+	.open           = peci_open,
+	.release        = peci_release,
+};
+
+static int peci_detect(struct peci_adapter *adapter, u8 addr)
+{
+	struct peci_ping_msg msg;
+
+	msg.addr = addr;
+
+	return peci_command(adapter, PECI_CMD_PING, &msg);
+}
+
+#if IS_ENABLED(CONFIG_OF)
+static const struct of_device_id *
+peci_of_match_device(const struct of_device_id *matches,
+		     struct peci_client *client)
+{
+	if (!(client && matches))
+		return NULL;
+
+	return of_match_device(matches, &client->dev);
+}
+#endif
+
+static const struct peci_device_id *
+peci_match_id(const struct peci_device_id *id, struct peci_client *client)
+{
+	if (!(id && client))
+		return NULL;
+
+	while (id->name[0]) {
+		if (strcmp(client->name, id->name) == 0)
+			return id;
+		id++;
+	}
+
+	return NULL;
+}
+
+static int peci_device_match(struct device *dev, struct device_driver *drv)
+{
+	struct peci_client *client = peci_verify_client(dev);
+	struct peci_driver *driver;
+
+	/* Attempt an OF style match */
+	if (peci_of_match_device(drv->of_match_table, client))
+		return 1;
+
+	driver = to_peci_driver(drv);
+
+	if (peci_match_id(driver->id_table, client))
+		return 1;
+
+	return 0;
+}
+
+static int peci_device_probe(struct device *dev)
+{
+	struct peci_client	*client = peci_verify_client(dev);
+	struct peci_driver	*driver;
+	int status = -EINVAL;
+
+	if (!client)
+		return 0;
+
+	if (!peci_of_match_device(dev->driver->of_match_table, client))
+		return -ENODEV;
+
+	dev_dbg(dev, "%s: name:%s\n", __func__, client->name);
+
+	driver = to_peci_driver(dev->driver);
+	if (driver->probe)
+		status = driver->probe(client);
+
+	return status;
+}
+
+static int peci_device_remove(struct device *dev)
+{
+	struct peci_client *client = peci_verify_client(dev);
+	struct peci_driver *driver;
+	int status = 0;
+
+	if (!client || !dev->driver)
+		return 0;
+
+	driver = to_peci_driver(dev->driver);
+	if (driver->remove) {
+		dev_dbg(dev, "%s: name:%s\n", __func__, client->name);
+		status = driver->remove(client);
+	}
+
+	return status;
+}
+
+static void peci_device_shutdown(struct device *dev)
+{
+	struct peci_client *client = peci_verify_client(dev);
+	struct peci_driver *driver;
+
+	if (!client || !dev->driver)
+		return;
+
+	dev_dbg(dev, "%s: name:%s\n", __func__, client->name);
+
+	driver = to_peci_driver(dev->driver);
+	if (driver->shutdown)
+		driver->shutdown(client);
+}
+
+static struct bus_type peci_bus_type = {
+	.name		= "peci",
+	.match		= peci_device_match,
+	.probe		= peci_device_probe,
+	.remove		= peci_device_remove,
+	.shutdown	= peci_device_shutdown,
+};
+
+static void peci_unregister_device(struct peci_client *client)
+{
+	if (client->dev.of_node)
+		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
+
+	device_unregister(&client->dev);
+}
+
+static int peci_check_addr_validity(u8 addr)
+{
+	if (addr < PECI_BASE_ADDR && addr > PECI_BASE_ADDR + PECI_OFFSET_MAX)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int peci_check_client_busy(struct device *dev, void *client_new_p)
+{
+	struct peci_client *client = peci_verify_client(dev);
+	struct peci_client *client_new = client_new_p;
+
+	if (client && client->addr == client_new->addr &&
+	    client->idx == client_new->idx)
+		return -EBUSY;
+
+	return 0;
+}
+
+static struct peci_client *peci_new_device(struct peci_adapter *adapter,
+					   struct peci_board_info const *info)
+{
+	struct peci_client *client;
+	int rc;
+
+	client = kzalloc(sizeof(*client), GFP_KERNEL);
+	if (!client)
+		return NULL;
+
+	client->adapter = adapter;
+	client->addr = info->addr;
+	strlcpy(client->name, info->type, sizeof(client->name));
+
+	rc = peci_check_addr_validity(client->addr);
+	if (rc) {
+		dev_err(&adapter->dev, "Invalid PECI CPU address 0x%02hx\n",
+			client->addr);
+		goto err_free_client_silent;
+	}
+
+	/* Check client's online status */
+	rc = peci_detect(adapter, client->addr);
+	if (rc)
+		goto err_free_client;
+
+	for (client->idx = 0; client->idx < PECI_DEV_IDX_MAX; client->idx++) {
+		rc = device_for_each_child(&adapter->dev, client,
+					   peci_check_client_busy);
+		if (!rc)
+			break;
+	}
+
+	if (rc || client->idx == PECI_DEV_IDX_MAX)
+		goto err_free_client;
+
+	client->dev.parent = &client->adapter->dev;
+	client->dev.bus = &peci_bus_type;
+	client->dev.type = &peci_client_type;
+	client->dev.of_node = info->of_node;
+	dev_set_name(&client->dev, "%d-%02x:%02x",
+		     adapter->nr, client->addr, client->idx);
+
+	rc = device_register(&client->dev);
+	if (rc)
+		goto err_free_client;
+
+	dev_dbg(&adapter->dev, "client [%s] registered with bus id %s\n",
+		client->name, dev_name(&client->dev));
+
+	return client;
+
+err_free_client:
+	dev_err(&adapter->dev,
+		"Failed to register peci client %s at 0x%02x (%d)\n",
+		client->name, client->addr, rc);
+err_free_client_silent:
+	kfree(client);
+	return NULL;
+}
+
+#if IS_ENABLED(CONFIG_OF)
+static struct peci_client *peci_of_register_device(struct peci_adapter *adapter,
+						   struct device_node *node)
+{
+	struct peci_board_info info = {};
+	struct peci_client *result;
+	const __be32 *addr_be;
+	u32 addr;
+	int len;
+
+	dev_dbg(&adapter->dev, "register %s\n", node->full_name);
+
+	if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
+		dev_err(&adapter->dev, "modalias failure on %s\n",
+			node->full_name);
+		return ERR_PTR(-EINVAL);
+	}
+
+	addr_be = of_get_property(node, "reg", &len);
+	if (!addr_be || len < sizeof(*addr_be)) {
+		dev_err(&adapter->dev, "invalid reg on %s\n",
+			node->full_name);
+		return ERR_PTR(-EINVAL);
+	}
+
+	addr = be32_to_cpup(addr_be);
+
+	if (peci_check_addr_validity(addr)) {
+		dev_err(&adapter->dev, "invalid addr=%x on %s\n",
+			addr, node->full_name);
+		return ERR_PTR(-EINVAL);
+	}
+
+	info.addr = addr;
+	info.of_node = of_node_get(node);
+
+	result = peci_new_device(adapter, &info);
+	if (!result)
+		result = ERR_PTR(-EINVAL);
+
+	of_node_put(node);
+	return result;
+}
+
+static void peci_of_register_devices(struct peci_adapter *adapter)
+{
+	struct device_node *bus, *node;
+	struct peci_client *client;
+
+	/* Only register child devices if the adapter has a node pointer set */
+	if (!adapter->dev.of_node)
+		return;
+
+	bus = of_get_child_by_name(adapter->dev.of_node, "peci-bus");
+	if (!bus)
+		bus = of_node_get(adapter->dev.of_node);
+
+	for_each_available_child_of_node(bus, node) {
+		if (of_node_test_and_set_flag(node, OF_POPULATED))
+			continue;
+
+		client = peci_of_register_device(adapter, node);
+		if (IS_ERR(client)) {
+			dev_warn(&adapter->dev,
+				 "Failed to create PECI device for %s\n",
+				 node->full_name);
+			of_node_clear_flag(node, OF_POPULATED);
+		}
+	}
+
+	of_node_put(bus);
+}
+
+static int peci_of_match_node(struct device *dev, void *data)
+{
+	return dev->of_node == data;
+}
+
+/* must call put_device() when done with returned peci_client device */
+static struct peci_client *peci_of_find_device(struct device_node *node)
+{
+	struct peci_client *client;
+	struct device *dev;
+
+	dev = bus_find_device(&peci_bus_type, NULL, node, peci_of_match_node);
+	if (!dev)
+		return NULL;
+
+	client = peci_verify_client(dev);
+	if (!client)
+		put_device(dev);
+
+	return client;
+}
+
+/* must call put_device() when done with returned peci_adapter device */
+static struct peci_adapter *peci_of_find_adapter(struct device_node *node)
+{
+	struct peci_adapter *adapter;
+	struct device *dev;
+
+	dev = bus_find_device(&peci_bus_type, NULL, node, peci_of_match_node);
+	if (!dev)
+		return NULL;
+
+	adapter = peci_verify_adapter(dev);
+	if (!adapter)
+		put_device(dev);
+
+	return adapter;
+}
+#else
+static void peci_of_register_devices(struct peci_adapter *adapter) { }
+#endif /* CONFIG_OF */
+
+#if IS_ENABLED(CONFIG_OF_DYNAMIC)
+static int peci_of_notify(struct notifier_block *nb,
+			  unsigned long action,
+			  void *arg)
+{
+	struct of_reconfig_data *rd = arg;
+	struct peci_adapter *adapter;
+	struct peci_client *client;
+
+	switch (of_reconfig_get_state_change(action, rd)) {
+	case OF_RECONFIG_CHANGE_ADD:
+		adapter = peci_of_find_adapter(rd->dn->parent);
+		if (!adapter)
+			return NOTIFY_OK;	/* not for us */
+
+		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
+			put_device(&adapter->dev);
+			return NOTIFY_OK;
+		}
+
+		client = peci_of_register_device(adapter, rd->dn);
+		put_device(&adapter->dev);
+
+		if (IS_ERR(client)) {
+			dev_err(&adapter->dev,
+				"failed to create client for '%s'\n",
+				rd->dn->full_name);
+			of_node_clear_flag(rd->dn, OF_POPULATED);
+			return notifier_from_errno(PTR_ERR(client));
+		}
+		break;
+	case OF_RECONFIG_CHANGE_REMOVE:
+		/* already depopulated? */
+		if (!of_node_check_flag(rd->dn, OF_POPULATED))
+			return NOTIFY_OK;
+
+		/* find our device by node */
+		client = peci_of_find_device(rd->dn);
+		if (!client)
+			return NOTIFY_OK;	/* no? not meant for us */
+
+		/* unregister takes one ref away */
+		peci_unregister_device(client);
+
+		/* and put the reference of the find */
+		put_device(&client->dev);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block peci_of_notifier = {
+	.notifier_call = peci_of_notify,
+};
+#else
+extern struct notifier_block peci_of_notifier;
+#endif /* CONFIG_OF_DYNAMIC */
+
+static int peci_register_adapter(struct peci_adapter *adapter)
+{
+	int rc = -EINVAL;
+
+	/* Can't register until after driver model init */
+	if (WARN_ON(!is_registered))
+		goto err_free_idr;
+
+	if (WARN(!adapter->name[0], "peci adapter has no name"))
+		goto err_free_idr;
+
+	if (WARN(!adapter->xfer, "peci adapter has no xfer function\n"))
+		goto err_free_idr;
+
+	rt_mutex_init(&adapter->bus_lock);
+
+	dev_set_name(&adapter->dev, "peci%d", adapter->nr);
+	adapter->dev.bus = &peci_bus_type;
+	adapter->dev.type = &peci_adapter_type;
+	device_initialize(&adapter->dev);
+
+	/* cdev */
+	cdev_init(&adapter->cdev, &peci_fops);
+	adapter->cdev.owner = THIS_MODULE;
+	adapter->cdev.kobj.parent = &adapter->dev.kobj;
+	adapter->dev.devt = MKDEV(MAJOR(peci_devt), adapter->nr);
+	rc = cdev_add(&adapter->cdev, adapter->dev.devt, 1);
+	if (rc) {
+		pr_err("adapter '%s': can't add cdev (%d)\n",
+		       adapter->name, rc);
+		goto err_free_idr;
+	}
+	rc = device_add(&adapter->dev);
+	if (rc) {
+		pr_err("adapter '%s': can't add device (%d)\n",
+		       adapter->name, rc);
+		goto err_del_cdev;
+	}
+
+	dev_dbg(&adapter->dev, "adapter [%s] registered\n", adapter->name);
+
+	/* create pre-declared device nodes */
+	peci_of_register_devices(adapter);
+
+	return 0;
+
+err_del_cdev:
+	cdev_del(&adapter->cdev);
+err_free_idr:
+	mutex_lock(&core_lock);
+	idr_remove(&peci_adapter_idr, adapter->nr);
+	mutex_unlock(&core_lock);
+	return rc;
+}
+
+static int peci_add_numbered_adapter(struct peci_adapter *adapter)
+{
+	int id;
+
+	mutex_lock(&core_lock);
+	id = idr_alloc(&peci_adapter_idr, adapter,
+		       adapter->nr, adapter->nr + 1, GFP_KERNEL);
+	mutex_unlock(&core_lock);
+	if (WARN(id < 0, "couldn't get idr"))
+		return id == -ENOSPC ? -EBUSY : id;
+
+	return peci_register_adapter(adapter);
+}
+
+int peci_add_adapter(struct peci_adapter *adapter)
+{
+	struct device *dev = &adapter->dev;
+	int id;
+
+	if (dev->of_node) {
+		id = of_alias_get_id(dev->of_node, "peci");
+		if (id >= 0) {
+			adapter->nr = id;
+			return peci_add_numbered_adapter(adapter);
+		}
+	}
+
+	mutex_lock(&core_lock);
+	id = idr_alloc(&peci_adapter_idr, adapter, 0, 0, GFP_KERNEL);
+	mutex_unlock(&core_lock);
+	if (WARN(id < 0, "couldn't get idr"))
+		return id;
+
+	adapter->nr = id;
+
+	return peci_register_adapter(adapter);
+}
+EXPORT_SYMBOL_GPL(peci_add_adapter);
+
+static int peci_unregister_client(struct device *dev, void *dummy)
+{
+	struct peci_client *client = peci_verify_client(dev);
+
+	if (client)
+		peci_unregister_device(client);
+
+	return 0;
+}
+
+void peci_del_adapter(struct peci_adapter *adapter)
+{
+	struct peci_adapter *found;
+
+	/* First make sure that this adapter was ever added */
+	mutex_lock(&core_lock);
+	found = idr_find(&peci_adapter_idr, adapter->nr);
+	mutex_unlock(&core_lock);
+
+	if (found != adapter)
+		return;
+
+	/**
+	 * Detach any active clients. This can't fail, thus we do not
+	 * check the returned value.
+	 */
+	device_for_each_child(&adapter->dev, NULL, peci_unregister_client);
+
+	/* device name is gone after device_unregister */
+	dev_dbg(&adapter->dev, "adapter [%s] unregistered\n", adapter->name);
+
+	device_unregister(&adapter->dev);
+
+	/* free cdev */
+	cdev_del(&adapter->cdev);
+
+	/* free bus id */
+	mutex_lock(&core_lock);
+	idr_remove(&peci_adapter_idr, adapter->nr);
+	mutex_unlock(&core_lock);
+}
+EXPORT_SYMBOL_GPL(peci_del_adapter);
+
+/**
+ * A peci_driver is used with one or more peci_client (device) nodes to access
+ * peci clients, on a bus instance associated with some peci_adapter.
+ */
+int peci_register_driver(struct module *owner, struct peci_driver *driver)
+{
+	int rc;
+
+	/* Can't register until after driver model init */
+	if (WARN_ON(!is_registered))
+		return -EAGAIN;
+
+	/* add the driver to the list of peci drivers in the driver core */
+	driver->driver.owner = owner;
+	driver->driver.bus = &peci_bus_type;
+
+	/**
+	 * When registration returns, the driver core
+	 * will have called probe() for all matching-but-unbound devices.
+	 */
+	rc = driver_register(&driver->driver);
+	if (rc)
+		return rc;
+
+	pr_debug("driver [%s] registered\n", driver->driver.name);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(peci_register_driver);
+
+void peci_del_driver(struct peci_driver *driver)
+{
+	driver_unregister(&driver->driver);
+	pr_debug("driver [%s] unregistered\n", driver->driver.name);
+}
+EXPORT_SYMBOL_GPL(peci_del_driver);
+
+static int __init peci_init(void)
+{
+	int ret;
+
+	ret = bus_register(&peci_bus_type);
+	if (ret < 0) {
+		pr_err("peci: Failed to register PECI bus type!\n");
+		return ret;
+	}
+
+	ret = alloc_chrdev_region(&peci_devt, 0, PECI_CDEV_MAX, "peci");
+	if (ret < 0) {
+		pr_err("peci: Failed to allocate chr dev region!\n");
+		bus_unregister(&peci_bus_type);
+		return ret;
+	}
+
+	crc8_populate_msb(peci_crc8_table, PECI_CRC8_POLYNOMIAL);
+
+	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
+		WARN_ON(of_reconfig_notifier_register(&peci_of_notifier));
+
+	is_registered = true;
+
+	return 0;
+}
+
+static void __exit peci_exit(void)
+{
+	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
+		WARN_ON(of_reconfig_notifier_unregister(&peci_of_notifier));
+
+	unregister_chrdev_region(peci_devt, PECI_CDEV_MAX);
+	bus_unregister(&peci_bus_type);
+}
+
+postcore_initcall(peci_init);
+module_exit(peci_exit);
+
+MODULE_AUTHOR("Jason M Biils <jason.m.bills@linux.intel.com>");
+MODULE_AUTHOR("Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>");
+MODULE_DESCRIPTION("PECI bus core module");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/peci.h b/include/linux/peci.h
new file mode 100644
index 000000000000..8730deb6673c
--- /dev/null
+++ b/include/linux/peci.h
@@ -0,0 +1,107 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2018 Intel Corporation */
+
+#ifndef __LINUX_PECI_H
+#define __LINUX_PECI_H
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/peci-ioctl.h>
+#include <linux/rtmutex.h>
+
+#define PECI_BUFFER_SIZE  32
+#define PECI_NAME_SIZE    32
+
+struct peci_xfer_msg {
+	u8	addr;
+	u8	tx_len;
+	u8	rx_len;
+	u8	tx_buf[PECI_BUFFER_SIZE];
+	u8	rx_buf[PECI_BUFFER_SIZE];
+} __attribute__((__packed__));
+
+struct peci_board_info {
+	char			type[PECI_NAME_SIZE];
+	u8			addr;	/* CPU client address */
+	struct device_node	*of_node;
+};
+
+struct peci_adapter {
+	struct module	*owner;
+	struct rt_mutex	bus_lock;
+	struct device	dev;
+	struct cdev	cdev;
+	int		nr;
+	char		name[PECI_NAME_SIZE];
+	int		(*xfer)(struct peci_adapter *adapter,
+				struct peci_xfer_msg *msg);
+	uint		cmd_mask;
+};
+
+static inline struct peci_adapter *to_peci_adapter(void *d)
+{
+	return container_of(d, struct peci_adapter, dev);
+}
+
+static inline void *peci_get_adapdata(const struct peci_adapter *adapter)
+{
+	return dev_get_drvdata(&adapter->dev);
+}
+
+static inline void peci_set_adapdata(struct peci_adapter *adapter, void *data)
+{
+	dev_set_drvdata(&adapter->dev, data);
+}
+
+struct peci_client {
+	struct device		dev;		/* the device structure */
+	struct peci_adapter	*adapter;	/* the adapter we sit on */
+	u8			addr;		/* CPU client address */
+	u8			idx;		/* device index */
+	char			name[PECI_NAME_SIZE];
+};
+
+static inline struct peci_client *to_peci_client(void *d)
+{
+	return container_of(d, struct peci_client, dev);
+}
+
+struct peci_device_id {
+	char		name[PECI_NAME_SIZE];
+	kernel_ulong_t	driver_data;	/* Data private to the driver */
+};
+
+struct peci_driver {
+	int				(*probe)(struct peci_client *client);
+	int				(*remove)(struct peci_client *client);
+	void				(*shutdown)(struct peci_client *client);
+	struct device_driver		driver;
+	const struct peci_device_id	*id_table;
+};
+
+static inline struct peci_driver *to_peci_driver(void *d)
+{
+	return container_of(d, struct peci_driver, driver);
+}
+
+/**
+ * module_peci_driver() - Helper macro for registering a modular PECI driver
+ * @__peci_driver: peci_driver struct
+ *
+ * Helper macro for PECI drivers which do not do anything special in module
+ * init/exit. This eliminates a lot of boilerplate. Each module may only
+ * use this macro once, and calling it replaces module_init() and module_exit()
+ */
+#define module_peci_driver(__peci_driver) \
+	module_driver(__peci_driver, peci_add_driver, peci_del_driver)
+
+/* use a define to avoid include chaining to get THIS_MODULE */
+#define peci_add_driver(driver) peci_register_driver(THIS_MODULE, driver)
+
+int  peci_register_driver(struct module *owner, struct peci_driver *drv);
+void peci_del_driver(struct peci_driver *driver);
+int  peci_add_adapter(struct peci_adapter *adapter);
+void peci_del_adapter(struct peci_adapter *adapter);
+int  peci_command(struct peci_adapter *adpater, enum peci_cmd cmd, void *vmsg);
+
+#endif /* __LINUX_PECI_H */
diff --git a/include/uapi/linux/peci-ioctl.h b/include/uapi/linux/peci-ioctl.h
new file mode 100644
index 000000000000..ec73847b9400
--- /dev/null
+++ b/include/uapi/linux/peci-ioctl.h
@@ -0,0 +1,200 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2018 Intel Corporation */
+
+#ifndef __PECI_IOCTL_H
+#define __PECI_IOCTL_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/* Base Address of 48d */
+#define PECI_BASE_ADDR  0x30  /* The PECI client's default address of 0x30 */
+#define PECI_OFFSET_MAX 8     /* Max numver of CPU clients */
+
+/* PCI Access */
+#define MAX_PCI_READ_LEN 24   /* Number of bytes of the PCI Space read */
+
+#define PCI_BUS0_CPU0      0x00
+#define PCI_BUS0_CPU1      0x80
+#define PCI_CPUBUSNO_BUS   0x00
+#define PCI_CPUBUSNO_DEV   0x08
+#define PCI_CPUBUSNO_FUNC  0x02
+#define PCI_CPUBUSNO       0xcc
+#define PCI_CPUBUSNO_1     0xd0
+#define PCI_CPUBUSNO_VALID 0xd4
+
+/* Package Identifier Read Parameter Value */
+#define PKG_ID_CPU_ID               0x0000  /* CPUID Info */
+#define PKG_ID_PLATFORM_ID          0x0001  /* Platform ID */
+#define PKG_ID_UNCORE_ID            0x0002  /* Uncore Device ID */
+#define PKG_ID_MAX_THREAD_ID        0x0003  /* Max Thread ID */
+#define PKG_ID_MICROCODE_REV        0x0004  /* CPU Microcode Update Revision */
+#define PKG_ID_MACHINE_CHECK_STATUS 0x0005  /* Machine Check Status */
+
+/* RdPkgConfig Index */
+#define MBX_INDEX_CPU_ID            0   /* Package Identifier Read */
+#define MBX_INDEX_VR_DEBUG          1   /* VR Debug */
+#define MBX_INDEX_PKG_TEMP_READ     2   /* Package Temperature Read */
+#define MBX_INDEX_ENERGY_COUNTER    3   /* Energy counter */
+#define MBX_INDEX_ENERGY_STATUS     4   /* DDR Energy Status */
+#define MBX_INDEX_WAKE_MODE_BIT     5   /* "Wake on PECI" Mode bit */
+#define MBX_INDEX_EPI               6   /* Efficient Performance Indication */
+#define MBX_INDEX_PKG_RAPL_PERF     8   /* Pkg RAPL Performance Status Read */
+#define MBX_INDEX_PER_CORE_DTS_TEMP 9   /* Per Core DTS Temperature Read */
+#define MBX_INDEX_DTS_MARGIN        10  /* DTS thermal margin */
+#define MBX_INDEX_SKT_PWR_THRTL_DUR 11  /* Socket Power Throttled Duration */
+#define MBX_INDEX_CFG_TDP_CONTROL   12  /* TDP Config Control */
+#define MBX_INDEX_CFG_TDP_LEVELS    13  /* TDP Config Levels */
+#define MBX_INDEX_DDR_DIMM_TEMP     14  /* DDR DIMM Temperature */
+#define MBX_INDEX_CFG_ICCMAX        15  /* Configurable ICCMAX */
+#define MBX_INDEX_TEMP_TARGET       16  /* Temperature Target Read */
+#define MBX_INDEX_CURR_CFG_LIMIT    17  /* Current Config Limit */
+#define MBX_INDEX_DIMM_TEMP_READ    20  /* Package Thermal Status Read */
+#define MBX_INDEX_DRAM_IMC_TMP_READ 22  /* DRAM IMC Temperature Read */
+#define MBX_INDEX_DDR_CH_THERM_STAT 23  /* DDR Channel Thermal Status */
+#define MBX_INDEX_PKG_POWER_LIMIT1  26  /* Package Power Limit1 */
+#define MBX_INDEX_PKG_POWER_LIMIT2  27  /* Package Power Limit2 */
+#define MBX_INDEX_TDP               28  /* Thermal design power minimum */
+#define MBX_INDEX_TDP_HIGH          29  /* Thermal design power maximum */
+#define MBX_INDEX_TDP_UNITS         30  /* Units for power/energy registers */
+#define MBX_INDEX_RUN_TIME          31  /* Accumulated Run Time */
+#define MBX_INDEX_CONSTRAINED_TIME  32  /* Thermally Constrained Time Read */
+#define MBX_INDEX_TURBO_RATIO       33  /* Turbo Activation Ratio */
+#define MBX_INDEX_DDR_RAPL_PL1      34  /* DDR RAPL PL1 */
+#define MBX_INDEX_DDR_PWR_INFO_HIGH 35  /* DRAM Power Info Read (high) */
+#define MBX_INDEX_DDR_PWR_INFO_LOW  36  /* DRAM Power Info Read (low) */
+#define MBX_INDEX_DDR_RAPL_PL2      37  /* DDR RAPL PL2 */
+#define MBX_INDEX_DDR_RAPL_STATUS   38  /* DDR RAPL Performance Status */
+#define MBX_INDEX_DDR_HOT_ABSOLUTE  43  /* DDR Hottest Dimm Absolute Temp */
+#define MBX_INDEX_DDR_HOT_RELATIVE  44  /* DDR Hottest Dimm Relative Temp */
+#define MBX_INDEX_DDR_THROTTLE_TIME 45  /* DDR Throttle Time */
+#define MBX_INDEX_DDR_THERM_STATUS  46  /* DDR Thermal Status */
+#define MBX_INDEX_TIME_AVG_TEMP     47  /* Package time-averaged temperature */
+#define MBX_INDEX_TURBO_RATIO_LIMIT 49  /* Turbo Ratio Limit Read */
+#define MBX_INDEX_HWP_AUTO_OOB      53  /* HWP Autonomous Out-of-band */
+#define MBX_INDEX_DDR_WARM_BUDGET   55  /* DDR Warm Power Budget */
+#define MBX_INDEX_DDR_HOT_BUDGET    56  /* DDR Hot Power Budget */
+#define MBX_INDEX_PKG_PSYS_PWR_LIM3 57  /* Package/Psys Power Limit3 */
+#define MBX_INDEX_PKG_PSYS_PWR_LIM1 58  /* Package/Psys Power Limit1 */
+#define MBX_INDEX_PKG_PSYS_PWR_LIM2 59  /* Package/Psys Power Limit2 */
+#define MBX_INDEX_PKG_PSYS_PWR_LIM4 60  /* Package/Psys Power Limit4 */
+#define MBX_INDEX_PERF_LIMIT_REASON 65  /* Performance Limit Reasons */
+
+/* WrPkgConfig Index */
+#define MBX_INDEX_DIMM_AMBIENT 19
+#define MBX_INDEX_DIMM_TEMP    24
+
+enum peci_cmd {
+	PECI_CMD_XFER = 0,
+	PECI_CMD_PING,
+	PECI_CMD_GET_DIB,
+	PECI_CMD_GET_TEMP,
+	PECI_CMD_RD_PKG_CFG,
+	PECI_CMD_WR_PKG_CFG,
+	PECI_CMD_RD_IA_MSR,
+	PECI_CMD_WR_IA_MSR,
+	PECI_CMD_RD_PCI_CFG,
+	PECI_CMD_WR_PCI_CFG,
+	PECI_CMD_RD_PCI_CFG_LOCAL,
+	PECI_CMD_WR_PCI_CFG_LOCAL,
+	PECI_CMD_MAX
+};
+
+struct peci_ping_msg {
+	__u8 addr;
+} __attribute__((__packed__));
+
+struct peci_get_dib_msg {
+	__u8  addr;
+	__u32 dib;
+} __attribute__((__packed__));
+
+struct peci_get_temp_msg {
+	__u8  addr;
+	__s16 temp_raw;
+} __attribute__((__packed__));
+
+struct peci_rd_pkg_cfg_msg {
+	__u8  addr;
+	__u8  index;
+	__u16 param;
+	__u8  rx_len;
+	__u8  pkg_config[4];
+} __attribute__((__packed__));
+
+struct peci_wr_pkg_cfg_msg {
+	__u8  addr;
+	__u8  index;
+	__u16 param;
+	__u8  tx_len;
+	__u32 value;
+} __attribute__((__packed__));
+
+struct peci_rd_ia_msr_msg {
+	__u8  addr;
+	__u8  thread_id;
+	__u16 address;
+	__u64 value;
+} __attribute__((__packed__));
+
+struct peci_rd_pci_cfg_msg {
+	__u8  addr;
+	__u8  bus;
+	__u8  device;
+	__u8  function;
+	__u16 reg;
+	__u8  pci_config[4];
+} __attribute__((__packed__));
+
+struct peci_rd_pci_cfg_local_msg {
+	__u8  addr;
+	__u8  bus;
+	__u8  device;
+	__u8  function;
+	__u16 reg;
+	__u8  rx_len;
+	__u8  pci_config[4];
+} __attribute__((__packed__));
+
+struct peci_wr_pci_cfg_local_msg {
+	__u8  addr;
+	__u8  bus;
+	__u8  device;
+	__u8  function;
+	__u16 reg;
+	__u8  tx_len;
+	__u32 value;
+} __attribute__((__packed__));
+
+#define PECI_IOC_BASE  0xb6
+
+#define PECI_IOC_PING \
+	_IOWR(PECI_IOC_BASE, PECI_CMD_PING, struct peci_ping_msg)
+
+#define PECI_IOC_GET_DIB \
+	_IOWR(PECI_IOC_BASE, PECI_CMD_GET_DIB, struct peci_get_dib_msg)
+
+#define PECI_IOC_GET_TEMP \
+	_IOWR(PECI_IOC_BASE, PECI_CMD_GET_TEMP, struct peci_get_temp_msg)
+
+#define PECI_IOC_RD_PKG_CFG \
+	_IOWR(PECI_IOC_BASE, PECI_CMD_RD_PKG_CFG, struct peci_rd_pkg_cfg_msg)
+
+#define PECI_IOC_WR_PKG_CFG \
+	_IOWR(PECI_IOC_BASE, PECI_CMD_WR_PKG_CFG, struct peci_wr_pkg_cfg_msg)
+
+#define PECI_IOC_RD_IA_MSR \
+	_IOWR(PECI_IOC_BASE, PECI_CMD_RD_IA_MSR, struct peci_rd_ia_msr_msg)
+
+#define PECI_IOC_RD_PCI_CFG \
+	_IOWR(PECI_IOC_BASE, PECI_CMD_RD_PCI_CFG, struct peci_rd_pci_cfg_msg)
+
+#define PECI_IOC_RD_PCI_CFG_LOCAL \
+	_IOWR(PECI_IOC_BASE, PECI_CMD_RD_PCI_CFG_LOCAL, \
+	      struct peci_rd_pci_cfg_local_msg)
+
+#define PECI_IOC_WR_PCI_CFG_LOCAL \
+	_IOWR(PECI_IOC_BASE, PECI_CMD_WR_PCI_CFG_LOCAL, \
+	      struct peci_wr_pci_cfg_local_msg)
+
+#endif /* __PECI_IOCTL_H */