Re: [PATCH linux v4 1/6] hwmon: Add core On-Chip Controller support for POWER CPUs

[Guenter Roeck]

On 01/26/2017 03:19 PM, eajames.ibm@xxxxxxxxx wrote:
> From: "Edward A. James" <eajames@xxxxxxxxxx>
>
> Add core support for polling the OCC for it's sensor data and parsing that
> data into sensor-specific information.
>
> Signed-off-by: Edward A. James <eajames@xxxxxxxxxx>
> Signed-off-by: Andrew Jeffery <andrew@xxxxxxxx>
> ---
>  Documentation/hwmon/occ    |  40 ++++
>  MAINTAINERS                |   7 +
>  drivers/hwmon/Kconfig      |   2 +
>  drivers/hwmon/Makefile     |   1 +
>  drivers/hwmon/occ/Kconfig  |  15 ++
>  drivers/hwmon/occ/Makefile |   1 +
>  drivers/hwmon/occ/occ.c    | 479 +++++++++++++++++++++++++++++++++++++++++++++
>  drivers/hwmon/occ/occ.h    |  80 ++++++++
>  drivers/hwmon/occ/scom.h   |  47 +++++
>  9 files changed, 672 insertions(+)
>  create mode 100644 Documentation/hwmon/occ
>  create mode 100644 drivers/hwmon/occ/Kconfig
>  create mode 100644 drivers/hwmon/occ/Makefile
>  create mode 100644 drivers/hwmon/occ/occ.c
>  create mode 100644 drivers/hwmon/occ/occ.h
>  create mode 100644 drivers/hwmon/occ/scom.h
>
> diff --git a/Documentation/hwmon/occ b/Documentation/hwmon/occ
> new file mode 100644
> index 0000000..79d1642
> --- /dev/null
> +++ b/Documentation/hwmon/occ
> @@ -0,0 +1,40 @@
> +Kernel driver occ
> +=================
> +
> +Supported chips:
> + * ASPEED AST2400
> + * ASPEED AST2500
> +
> +Please note that the chip must be connected to a POWER8 or POWER9 processor
> +(see the BMC - Host Communications section).
> +
> +Author: Eddie James <eajames@xxxxxxxxxx>
> +
> +Description
> +-----------
> +
> +This driver implements support for the OCC (On-Chip Controller) on the IBM
> +POWER8 and POWER9 processors, from a BMC (Baseboard Management Controller). The
> +OCC is an embedded processor that provides real time power and thermal
> +monitoring.
> +
> +This driver provides an interface on a BMC to poll OCC sensor data, set user
> +power caps, and perform some basic OCC error handling.
> +
> +Currently, all versions of the OCC support four types of sensor data: power,
> +temperature, frequency, and "caps," which indicate limits and thresholds used
> +internally on the OCC.
> +
> +BMC - Host Communications
> +-------------------------
> +
> +For the POWER8 application, the BMC can communicate with the P8 over I2C bus.
> +However, to access the OCC register space, any data transfer must use a SCOM
> +operation. SCOM is a procedure to initiate a data transfer, typically of 8
> +bytes. SCOMs consist of writing a 32-bit command register and then
> +reading/writing two 32-bit data registers. This driver implements these
> +SCOM operations over I2C bus in order to communicate with the OCC.
> +
> +For the POWER9 application, the BMC can communicate with the P9 over FSI bus
> +and SBE engine. Once again, SCOM operations are required. This driver will
> +implement SCOM ops over FSI/SBE. This will require the FSI driver.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 5f0420a..f5d4195 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9112,6 +9112,13 @@ T:	git git://linuxtv.org/media_tree.git
>  S:	Maintained
>  F:	drivers/media/i2c/ov7670.c
>
> +ON-CHIP CONTROLLER HWMON DRIVER
> +M:	Eddie James <eajames@xxxxxxxxxx>
> +L:	linux-hwmon@xxxxxxxxxxxxxxx
> +S:	Maintained
> +F:	Documentation/hwmon/occ
> +F:	drivers/hwmon/occ/
> +
>  ONENAND FLASH DRIVER
>  M:	Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
>  L:	linux-mtd@xxxxxxxxxxxxxxxxxxx
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 190d270..e80ca81 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1240,6 +1240,8 @@ config SENSORS_NSA320
>  	  This driver can also be built as a module. If so, the module
>  	  will be called nsa320-hwmon.
>
> +source drivers/hwmon/occ/Kconfig
> +
>  config SENSORS_PCF8591
>  	tristate "Philips PCF8591 ADC/DAC"
>  	depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index d2cb7e8..c7ec5d4 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -169,6 +169,7 @@ obj-$(CONFIG_SENSORS_WM831X)	+= wm831x-hwmon.o
>  obj-$(CONFIG_SENSORS_WM8350)	+= wm8350-hwmon.o
>  obj-$(CONFIG_SENSORS_XGENE)	+= xgene-hwmon.o
>
> +obj-$(CONFIG_SENSORS_PPC_OCC)	+= occ/
>  obj-$(CONFIG_PMBUS)		+= pmbus/
>
>  ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG
> diff --git a/drivers/hwmon/occ/Kconfig b/drivers/hwmon/occ/Kconfig
> new file mode 100644
> index 0000000..cdb64a7
> --- /dev/null
> +++ b/drivers/hwmon/occ/Kconfig
> @@ -0,0 +1,15 @@
> +#
> +# On Chip Controller configuration
> +#
> +
> +menuconfig SENSORS_PPC_OCC
> +	bool "PPC On-Chip Controller"
> +	help
> +	  If you say yes here you get support to monitor Power CPU
> +	  sensors via the On-Chip Controller (OCC).
> +
> +	  Generally this is used by management controllers such as a BMC
> +	  on an OpenPower system.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called occ.
> diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
> new file mode 100644
> index 0000000..93cb52f
> --- /dev/null
> +++ b/drivers/hwmon/occ/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o
> diff --git a/drivers/hwmon/occ/occ.c b/drivers/hwmon/occ/occ.c
> new file mode 100644
> index 0000000..3b233d8
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ.c
> @@ -0,0 +1,479 @@
> +/*
> + * occ.c - OCC hwmon driver
> + *
> + * This file contains the methods and data structures for the OCC hwmon driver.
> + *
> + * Copyright 2016 IBM Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This 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.
> + */
> +
> +#include <asm/unaligned.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/jiffies.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/slab.h>
> +#include "occ.h"
> +
> +#define OCC_DATA_MAX		4096
> +#define OCC_DATA_MIN		40
> +#define OCC_BMC_TIMEOUT_MS	20000
> +
> +/* To generate attn to OCC */
> +#define ATTN_DATA		0x0006B035
> +
> +/* For BMC to read/write SRAM */
> +#define OCB_ADDRESS		0x0006B070
> +#define OCB_DATA		0x0006B075
> +#define OCB_STATUS_CONTROL_AND	0x0006B072
> +#define OCB_STATUS_CONTROL_OR	0x0006B073
> +
> +/* To init OCB */
> +#define OCB_AND_INIT0		0xFBFFFFFF
> +#define OCB_AND_INIT1		0xFFFFFFFF
> +#define OCB_OR_INIT0		0x08000000
> +#define OCB_OR_INIT1		0x00000000
> +
> +/* To generate attention on OCC */
> +#define ATTN0			0x01010000
> +#define ATTN1			0x00000000
> +
> +/* OCC return status */
> +#define RESP_RETURN_CMD_IN_PRG	0xFF
> +#define RESP_RETURN_SUCCESS	0
> +#define RESP_RETURN_CMD_INVAL	0x11
> +#define RESP_RETURN_CMD_LEN	0x12
> +#define RESP_RETURN_DATA_INVAL	0x13
> +#define RESP_RETURN_CHKSUM	0x14
> +#define RESP_RETURN_OCC_ERR	0x15
> +#define RESP_RETURN_STATE	0x16
> +
> +/* time interval to retry on "command in progress" return status */
> +#define CMD_IN_PRG_INT_MS	100
> +#define CMD_IN_PRG_RETRIES	(OCC_BMC_TIMEOUT_MS / CMD_IN_PRG_INT_MS)
> +
> +/* OCC command definitions */
> +#define OCC_POLL		0
> +#define OCC_SET_USER_POWR_CAP	0x22
> +
> +/* OCC poll command data */
> +#define OCC_POLL_STAT_SENSOR	0x10
> +
> +/* OCC response data offsets */
> +#define RESP_RETURN_STATUS		2
> +#define RESP_DATA_LENGTH		3
> +#define RESP_HEADER_OFFSET		5
> +#define SENSOR_STR_OFFSET		37
> +#define NUM_SENSOR_BLOCKS_OFFSET	43
> +#define SENSOR_BLOCK_OFFSET		45
> +
> +/* occ_poll_header
> + * structure to match the raw occ poll response data
> + */
> +struct occ_poll_header {
> +	u8 status;
> +	u8 ext_status;
> +	u8 occs_present;
> +	u8 config;
> +	u8 occ_state;
> +	u8 mode;
> +	u8 ips_status;
> +	u8 error_log_id;
> +	u32 error_log_addr_start;
> +	u16 error_log_length;
> +	u8 reserved2;
> +	u8 reserved3;
> +	u8 occ_code_level[16];
> +	u8 sensor_eye_catcher[6];
> +	u8 num_sensor_blocks;
> +	u8 sensor_data_version;
> +} __attribute__((packed, aligned(4)));
> +
> +struct occ_response {
> +	struct occ_poll_header header;
> +	struct occ_blocks data;
> +};
> +
> +struct occ {
> +	struct device *dev;
> +	void *bus;
> +	struct occ_bus_ops bus_ops;
> +	struct occ_ops ops;
> +	struct occ_config config;
> +	unsigned long update_interval;
> +	unsigned long last_updated;
> +	struct mutex update_lock;
> +	struct occ_response response;
> +	bool valid;
> +	u8 *raw_data;
> +};
> +
> +static int occ_check_sensor(struct occ *driver, u8 sensor_length,
> +			    u8 num_sensors, enum sensor_type t, int b)
> +{
> +	struct occ_response *resp = &driver->response;
> +	struct sensor_data_block *block = &resp->data.blocks[b];
> +
> +	if (block->sensors) {
> +		/* empty block, release old data */
> +		if (num_sensors == 0 || sensor_length == 0) {
> +			devm_kfree(driver->dev, block->sensors);
> +			block->sensors = NULL;
> +			return -ENODATA;
> +		}
> +
> +		/* different num sensors or length, re-alloc */
> +		if (num_sensors != block->header.num_sensors ||
> +		    sensor_length != block->header.sensor_length)
> +			devm_kfree(driver->dev, block->sensors);
> +		else
> +			return 0;
> +	}
> +
> +	/* each sensor type is a different size */
> +	block->sensors = driver->ops.alloc_sensor(t, num_sensors);
> +	if (!block->sensors)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +
> +static int parse_occ_response(struct occ *driver, u16 num_bytes)
> +{
> +	int b;
> +	int s;
> +	int rc;
> +	unsigned int offset = SENSOR_BLOCK_OFFSET;
> +	int sensor_type;
> +	u8 num_sensor_blocks;
> +	struct sensor_data_block_header *block;
> +	struct device *dev = driver->dev;
> +	u8 *data = driver->raw_data;
> +	struct occ_response *resp = &driver->response;
> +
> +	/* check if the data is valid */
> +	if (strncmp(&data[SENSOR_STR_OFFSET], "SENSOR", 6) != 0) {
> +		dev_err(dev, "no SENSOR string in response\n");
> +		rc = -ENODATA;
> +		goto err;
> +	}
> +
> +	num_sensor_blocks = data[NUM_SENSOR_BLOCKS_OFFSET];
> +	if (num_sensor_blocks == 0) {
> +		dev_warn(dev, "no sensor blocks available\n");
> +		rc = -ENODATA;
> +		goto err;
> +	}
> +
> +	memcpy(&resp->header, &data[RESP_HEADER_OFFSET],
> +	       sizeof(struct occ_poll_header));
> +
> +	/* data length starts at actual data */
> +	num_bytes += RESP_HEADER_OFFSET;
> +
> +	/* translate fields > 1 byte */
> +	resp->header.error_log_addr_start =
> +		be32_to_cpu(resp->header.error_log_addr_start);
> +	resp->header.error_log_length =
> +		be16_to_cpu(resp->header.error_log_length);
> +
> +	for (b = 0; b < num_sensor_blocks && b < MAX_OCC_SENSOR_TYPE; b++) {
> +		if (offset + sizeof(struct sensor_data_block_header) >
> +		    num_bytes) {
> +			dev_warn(dev, "exceeded data length\n");
> +			goto err;
> +		}
> +
> +		block = (struct sensor_data_block_header *)&data[offset];
> +		offset += sizeof(struct sensor_data_block_header);
> +
> +		if (strncmp(block->sensor_type, "FREQ", 4) == 0)
> +			sensor_type = FREQ;
> +		else if (strncmp(block->sensor_type, "TEMP", 4) == 0)
> +			sensor_type = TEMP;
> +		else if (strncmp(block->sensor_type, "POWR", 4) == 0)
> +			sensor_type = POWER;
> +		else if (strncmp(block->sensor_type, "CAPS", 4) == 0)
> +			sensor_type = CAPS;
> +		else {
> +			dev_warn(dev, "sensor type not supported %.4s\n",
> +				block->sensor_type);
> +			continue;
> +		}
> +
> +		rc = occ_check_sensor(driver, block->sensor_length,
> +				      block->num_sensors, sensor_type, b);
> +		if (rc == -ENOMEM)
> +			goto err;
> +		else if (rc)
> +			continue;
> +
> +		resp->data.sensor_block_id[sensor_type] = b;
> +		/* copy block data over to response pointer */
> +		resp->data.blocks[b].header = *block;
> +		for (s = 0; s < block->num_sensors; s++) {
> +			if (offset + block->sensor_length > num_bytes) {
> +				dev_warn(dev, "exceeded data length\n");
> +				goto err;
> +			}
> +
> +			driver->ops.parse_sensor(data,
> +						 resp->data.blocks[b].sensors,
> +						 sensor_type, offset, s);
> +			offset += block->sensor_length;
> +		}
> +	}
> +
> +	return 0;
> +err:
> +	return rc;

Please no unnecessary gotos. The code jumping here can return directly.

> +}
> +
> +static u8 occ_send_cmd(struct occ *driver, u8 seq, u8 type, u16 length,
> +		       const u8 *data, u8 *resp)
> +{
> +	u32 cmd1, cmd2 = 0;
> +	u16 checksum = 0;
> +	bool retry = false;
> +	int i, rc, tries = 0;
> +
> +	cmd1 = (seq << 24) | (type << 16) | length;
> +	memcpy(&cmd2, data, length);
> +	cmd2 <<= ((4 - length) * 8);
> +
> +	/* checksum: sum of every bytes of cmd1, cmd2 */
> +	for (i = 0; i < 4; i++) {
> +		checksum += (cmd1 >> (i * 8)) & 0xFF;
> +		checksum += (cmd2 >> (i * 8)) & 0xFF;
> +	}
> +
> +	cmd2 |= checksum << ((2 - length) * 8);
> +
> +	/* Init OCB */
> +	rc = driver->bus_ops.putscom(driver->bus, OCB_STATUS_CONTROL_OR,
> +				     OCB_OR_INIT0, OCB_OR_INIT1);
> +	if (rc)
> +		goto err;
> +
> +	rc = driver->bus_ops.putscom(driver->bus, OCB_STATUS_CONTROL_AND,
> +				     OCB_AND_INIT0, OCB_AND_INIT1);
> +	if (rc)
> +		goto err;
> +
> +	/* Send command, 2nd half of the 64-bit addr is unused (write 0) */
> +	rc = driver->bus_ops.putscom(driver->bus, OCB_ADDRESS,
> +				     driver->config.command_addr, 0);
> +	if (rc)
> +		goto err;
> +
> +	rc = driver->bus_ops.putscom(driver->bus, OCB_DATA, cmd1, cmd2);
> +	if (rc)
> +		goto err;
> +
> +	/* Trigger attention */
> +	rc = driver->bus_ops.putscom(driver->bus, ATTN_DATA, ATTN0, ATTN1);
> +	if (rc)
> +		goto err;
> +
> +	/* Get response data */
> +	rc = driver->bus_ops.putscom(driver->bus, OCB_ADDRESS,
> +				     driver->config.response_addr, 0);
> +	if (rc)
> +		goto err;
> +
> +	do {
> +		if (retry) {
> +			set_current_state(TASK_INTERRUPTIBLE);
> +			schedule_timeout(msecs_to_jiffies(CMD_IN_PRG_INT_MS));
> +		}
> +
> +		rc = driver->bus_ops.getscom(driver->bus, OCB_DATA,
> +					     (u64 *)resp);
> +		if (rc)
> +			goto err;
> +
> +		/* retry if we get "command in progress" return status */
> +		retry = resp[RESP_RETURN_STATUS] == RESP_RETURN_CMD_IN_PRG &&
> +			tries++ < CMD_IN_PRG_RETRIES;
> +	} while (retry);
> +
> +	/* check the occ response */
> +	switch (resp[RESP_RETURN_STATUS]) {
> +	case RESP_RETURN_CMD_IN_PRG:
> +		rc = -EALREADY;
> +		break;
> +	case RESP_RETURN_SUCCESS:
> +		rc = 0;
> +		break;
> +	case RESP_RETURN_CMD_INVAL:
> +	case RESP_RETURN_CMD_LEN:
> +	case RESP_RETURN_DATA_INVAL:
> +	case RESP_RETURN_CHKSUM:
> +		rc = -EINVAL;
> +		break;
> +	case RESP_RETURN_OCC_ERR:
> +		rc = -EREMOTE;
> +		break;
> +	default:
> +		rc = -EFAULT;
> +	}
> +
> +	if (rc < 0)
> +		dev_warn(driver->dev, "occ bad response:%d\n",
> +			 resp[RESP_RETURN_STATUS]);
> +
> +	return rc;
> +
> +err:
> +	dev_err(driver->dev, "scom op failed rc:%d\n", rc);
> +	return rc;
> +}
> +
> +static int occ_get_all(struct occ *driver)
> +{
> +	int i = 0, rc;
> +	u8 *occ_data = driver->raw_data;
> +	u16 num_bytes;
> +	const u8 poll_cmd_data = OCC_POLL_STAT_SENSOR;
> +	struct device *dev = driver->dev;
> +
> +	memset(occ_data, 0, OCC_DATA_MAX);
> +
> +	rc = occ_send_cmd(driver, 0, OCC_POLL, 1, &poll_cmd_data, occ_data);
> +	if (rc)
> +		goto out;
> +
> +	num_bytes = get_unaligned((u16 *)&occ_data[RESP_DATA_LENGTH]);
> +	num_bytes = be16_to_cpu(num_bytes);
> +
> +	if (num_bytes > OCC_DATA_MAX || num_bytes < OCC_DATA_MIN) {
> +		dev_err(dev, "bad OCC data length:%d\n", num_bytes);
> +		rc = -EINVAL;
> +		goto out;
> +	}
> +
> +	/* read remaining data, 8 byte scoms at a time */
> +	for (i = 8; i < num_bytes + 8; i += 8) {
> +		rc = driver->bus_ops.getscom(driver->bus, OCB_DATA,
> +					     (u64 *)&occ_data[i]);
> +		if (rc) {
> +			dev_err(dev, "getscom op failed rc:%d\n", rc);
> +			goto out;
> +		}
> +	}
> +
> +	/* don't need more sanity checks; buffer is alloc'd for max response
> +	 * size so we just check for valid data in parse_occ_response
> +	 */
> +	rc = parse_occ_response(driver, num_bytes);
> +
> +out:

Same as above - this label is unnecessary.

> +	return rc;
> +}
> +
> +int occ_update_device(struct occ *driver)
> +{
> +	int rc = 0;
> +
> +	mutex_lock(&driver->update_lock);
> +
> +	if (time_after(jiffies, driver->last_updated + driver->update_interval)

Can you make update_interval a constant ?

> +	    || !driver->valid) {
> +		driver->valid = true;
> +
> +		rc = occ_get_all(driver);
> +		if (rc)
> +			driver->valid = false;
> +
> +		driver->last_updated = jiffies;
> +	}
> +
> +	mutex_unlock(&driver->update_lock);
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL(occ_update_device);
> +
> +void *occ_get_sensor(struct occ *driver, int sensor_type)
> +{
> +	int rc;
> +	int type_id;
> +
> +	/* occ_update_device locks the update lock */
> +	rc = occ_update_device(driver);
> +	if (rc)
> +		return NULL;

NULL or ERR_PTR() ?

> +
> +	type_id = driver->response.data.sensor_block_id[sensor_type];
> +	if (type_id == -1)
> +		return NULL;
> +
> +	return driver->response.data.blocks[type_id].sensors;
> +}
> +EXPORT_SYMBOL(occ_get_sensor);
> +
> +int occ_get_sensor_field(struct occ *occ, int sensor_type, int sensor_num,
> +			 u32 hwmon, long *val)
> +{
> +	return occ->ops.get_sensor(occ, sensor_type, sensor_num, hwmon, val);
> +}
> +EXPORT_SYMBOL(occ_get_sensor_value);

Ad 0day found, something got messed up here. Please fix and resubmit.

> +
> +void occ_get_response_blocks(struct occ *occ, struct occ_blocks **blocks)
> +{
> +	*blocks = &occ->response.data;
> +}
> +EXPORT_SYMBOL(occ_get_response_blocks);
> +
> +int occ_set_user_powercap(struct occ *occ, u16 cap)
> +{
> +	u8 resp[8];
> +
> +	cap = cpu_to_be16(cap);
> +
> +	return occ_send_cmd(occ, 0, OCC_SET_USER_POWR_CAP, 2, (const u8 *)&cap,
> +			    resp);
> +}
> +EXPORT_SYMBOL(occ_set_user_powercap);
> +
> +struct occ *occ_start(struct device *dev, void *bus,
> +		      struct occ_bus_ops *bus_ops, const struct occ_ops *ops,
> +		      const struct occ_config *config)
> +{
> +	struct occ *driver = devm_kzalloc(dev, sizeof(struct occ), GFP_KERNEL);
> +
> +	if (!driver)
> +		return ERR_PTR(-ENOMEM);
> +
> +	driver->dev = dev;
> +	driver->bus = bus;
> +	driver->bus_ops = *bus_ops;
> +	driver->ops = *ops;
> +	driver->config = *config;
> +	driver->raw_data = devm_kzalloc(dev, OCC_DATA_MAX, GFP_KERNEL);
> +	if (!driver->raw_data)
> +		return ERR_PTR(-ENOMEM);
> +
> +	driver->update_interval = HZ;
> +	mutex_init(&driver->update_lock);
> +
> +	return driver;
> +}
> +EXPORT_SYMBOL(occ_start);
> +
> +MODULE_AUTHOR("Eddie James <eajames@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("OCC hwmon core driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/hwmon/occ/occ.h b/drivers/hwmon/occ/occ.h
> new file mode 100644
> index 0000000..41f11b2
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ.h
> @@ -0,0 +1,80 @@
> +/*
> + * occ.h - hwmon OCC driver
> + *
> + * This file contains data structures and function prototypes for common access
> + * between different bus protocols and host systems.
> + *
> + * Copyright 2016 IBM Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This 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.
> + */
> +
> +#ifndef __OCC_H__
> +#define __OCC_H__
> +
> +#include "scom.h"
> +
> +struct device;
> +struct occ;
> +
> +/* sensor_data_block_header
> + * structure to match the raw occ sensor block header
> + */
> +struct sensor_data_block_header {
> +	u8 sensor_type[4];
> +	u8 reserved0;
> +	u8 sensor_format;
> +	u8 sensor_length;
> +	u8 num_sensors;
> +} __attribute__((packed, aligned(4)));
> +
> +struct sensor_data_block {
> +	struct sensor_data_block_header header;
> +	void *sensors;
> +};
> +
> +enum sensor_type {
> +	FREQ = 0,
> +	TEMP,
> +	POWER,
> +	CAPS,
> +	MAX_OCC_SENSOR_TYPE
> +};
> +
> +struct occ_ops {
> +	void (*parse_sensor)(u8 *data, void *sensor, int sensor_type, int off,
> +			     int snum);
> +	void *(*alloc_sensor)(int sensor_type, int num_sensors);
> +	int (*get_sensor)(struct occ *driver, int sensor_type, int sensor_num,
> +			  u32 hwmon, long *val);
> +};
> +
> +struct occ_config {
> +	u32 command_addr;
> +	u32 response_addr;
> +};
> +
> +struct occ_blocks {
> +	int sensor_block_id[MAX_OCC_SENSOR_TYPE];
> +	struct sensor_data_block blocks[MAX_OCC_SENSOR_TYPE];
> +};
> +
> +struct occ *occ_start(struct device *dev, void *bus,
> +		      struct occ_bus_ops *bus_ops, const struct occ_ops *ops,
> +		      const struct occ_config *config);
> +void *occ_get_sensor(struct occ *occ, int sensor_type);
> +int occ_get_sensor_field(struct occ *occ, int sensor_type, int sensor_num,
> +			 u32 hwmon, long *val);
> +void occ_get_response_blocks(struct occ *occ, struct occ_blocks **blocks);
> +int occ_update_device(struct occ *driver);
> +int occ_set_user_powercap(struct occ *occ, u16 cap);
> +
> +#endif /* __OCC_H__ */
> diff --git a/drivers/hwmon/occ/scom.h b/drivers/hwmon/occ/scom.h
> new file mode 100644
> index 0000000..b0691f3
> --- /dev/null
> +++ b/drivers/hwmon/occ/scom.h
> @@ -0,0 +1,47 @@
> +/*
> + * scom.h - hwmon OCC driver
> + *
> + * This file contains data structures for scom operations to the OCC
> + *
> + * Copyright 2016 IBM Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This 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.
> + */
> +
> +#ifndef __SCOM_H__
> +#define __SCOM_H__
> +
> +/*
> + * occ_bus_ops - represent the low-level transfer methods to communicate with
> + * the OCC.
> + *
> + * getscom - OCC scom read
> + * @bus: handle to slave device
> + * @address: address
> + * @data: where to store data read from slave; buffer size must be at least
> + * eight bytes.
> + *
> + * Returns 0 on success or a negative errno on error
> + *
> + * putscom - OCC scom write
> + * @bus: handle to slave device
> + * @address: address
> + * @data0: first data word to write
> + * @data1: second data word to write
> + *
> + * Returns 0 on success or a negative errno on error
> + */
> +struct occ_bus_ops {
> +	int (*getscom)(void *bus, u32 address, u64 *data);
> +	int (*putscom)(void *bus, u32 address, u32 data0, u32 data1);
> +};
> +
> +#endif /* __SCOM_H__ */