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Date:   Wed, 25 Jul 2018 09:19:28 -0700
From:   Guenter Roeck <linux@roeck-us.net>
To:     Eddie James <eajames@linux.vnet.ibm.com>
Cc:     linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org,
        devicetree@vger.kernel.org, linux-doc@vger.kernel.org,
        gregkh@linuxfoundation.org, benh@kernel.crashing.org,
        jdelvare@suse.com, mark.rutland@arm.com, openbmc@lists.ozlabs.org,
        robh+dt@kernel.org, joel@jms.id.au,
        Andrew Jeffery <andrew@aj.id.au>
Subject: Re: [PATCH v4 1/9] fsi: Add On-Chip Controller (OCC) driver
Message-ID: <20180725161928.GA21161@roeck-us.net>
References: <1531342898-15790-1-git-send-email-eajames@linux.vnet.ibm.com>
 <1531342898-15790-2-git-send-email-eajames@linux.vnet.ibm.com>
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On Wed, Jul 11, 2018 at 04:01:30PM -0500, Eddie James wrote:
> The OCC is a device embedded on a POWER processor that collects and
> aggregates sensor data from the processor and system. The OCC can
> provide the raw sensor data as well as perform thermal and power
> management on the system.
> 
> This driver provides an atomic communications channel between a service
> processor (e.g. a BMC) and the OCC. The driver is dependent on the FSI
> SBEFIFO driver to get hardware access through the SBE to the OCC SRAM.
> Commands are issued to the SBE to send or fetch data to the SRAM.
> 
> Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Signed-off-by: Joel Stanley <joel@jms.id.au>
> ---
>  drivers/fsi/Kconfig     |  10 +
>  drivers/fsi/Makefile    |   1 +
>  drivers/fsi/fsi-occ.c   | 609 ++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/fsi-occ.h |  34 +++
>  4 files changed, 654 insertions(+)
>  create mode 100644 drivers/fsi/fsi-occ.c
>  create mode 100644 include/linux/fsi-occ.h
> 
> diff --git a/drivers/fsi/Kconfig b/drivers/fsi/Kconfig
> index 24f84a9..322cec3 100644
> --- a/drivers/fsi/Kconfig
> +++ b/drivers/fsi/Kconfig
> @@ -39,4 +39,14 @@ config FSI_SBEFIFO
>  	a pipe-like FSI device for communicating with the self boot engine
>  	(SBE) on POWER processors.
>  
> +config FSI_OCC
> +	tristate "OCC SBEFIFO client device driver"
> +	depends on FSI_SBEFIFO
> +	---help---
> +	This option enables an SBEFIFO based On-Chip Controller (OCC) device
> +	driver. The OCC is a device embedded on a POWER processor that collects
> +	and aggregates sensor data from the processor and system. The OCC can
> +	provide the raw sensor data as well as perform thermal and power
> +	management on the system.
> +
>  endif
> diff --git a/drivers/fsi/Makefile b/drivers/fsi/Makefile
> index 851182e..75fdc6d 100644
> --- a/drivers/fsi/Makefile
> +++ b/drivers/fsi/Makefile
> @@ -4,3 +4,4 @@ obj-$(CONFIG_FSI_MASTER_HUB) += fsi-master-hub.o
>  obj-$(CONFIG_FSI_MASTER_GPIO) += fsi-master-gpio.o
>  obj-$(CONFIG_FSI_SCOM) += fsi-scom.o
>  obj-$(CONFIG_FSI_SBEFIFO) += fsi-sbefifo.o
> +obj-$(CONFIG_FSI_OCC) += fsi-occ.o
> diff --git a/drivers/fsi/fsi-occ.c b/drivers/fsi/fsi-occ.c
> new file mode 100644
> index 0000000..bba67a6
> --- /dev/null
> +++ b/drivers/fsi/fsi-occ.c
> @@ -0,0 +1,609 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * On-Chip Controller Driver
> + *
> + * Copyright (C) IBM Corporation 2018
> + *
> + * 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.

I thought the whole idea of using SPDX license identifiers was to get rid
of this boilerplate.

> + */
> +
> +#include <asm/unaligned.h>

asm includes should be after generic includes.

> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +#include <linux/fs.h>
> +#include <linux/fsi-sbefifo.h>
> +#include <linux/gfp.h>
> +#include <linux/idr.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/fsi-occ.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/sched.h>
> +#include <linux/slab.h>
> +#include <linux/uaccess.h>
> +
> +#define OCC_SRAM_BYTES		4096
> +#define OCC_CMD_DATA_BYTES	4090
> +#define OCC_RESP_DATA_BYTES	4089
> +
> +#define OCC_SRAM_CMD_ADDR	0xFFFBE000
> +#define OCC_SRAM_RSP_ADDR	0xFFFBF000
> +
> +/*
> + * Assume we don't have much FFDC, if we do we'll overflow and
> + * fail the command. This needs to be big enough for simple
> + * commands as well.
> + */
> +#define OCC_SBE_STATUS_WORDS	32
> +
> +#define OCC_TIMEOUT_MS		1000
> +#define OCC_CMD_IN_PRG_WAIT_MS	50
> +
> +struct occ {
> +	struct device *dev;
> +	struct device *sbefifo;
> +	char name[32];
> +	int idx;
> +	struct miscdevice mdev;
> +	struct mutex occ_lock;
> +};
> +
> +#define to_occ(x)	container_of((x), struct occ, mdev)
> +
> +struct occ_response {
> +	u8 seq_no;
> +	u8 cmd_type;
> +	u8 return_status;
> +	__be16 data_length;
> +	u8 data[OCC_RESP_DATA_BYTES + 2];	/* two bytes checksum */
> +} __packed;
> +
> +struct occ_client {
> +	struct occ *occ;
> +	struct mutex lock;
> +	size_t data_size;
> +	size_t read_offset;
> +	u8 *buffer;
> +};
> +
> +#define to_client(x)	container_of((x), struct occ_client, xfr)
> +
> +static DEFINE_IDA(occ_ida);
> +
> +static int occ_open(struct inode *inode, struct file *file)
> +{
> +	struct occ_client *client = kzalloc(sizeof(*client), GFP_KERNEL);
> +	struct miscdevice *mdev = file->private_data;
> +	struct occ *occ = to_occ(mdev);
> +
> +	if (!client)
> +		return -ENOMEM;
> +
> +	client->buffer = (u8 *)__get_free_page(GFP_KERNEL);
> +	if (!client->buffer) {
> +		kfree(client);
> +		return -ENOMEM;
> +	}
> +
> +	client->occ = occ;
> +	mutex_init(&client->lock);
> +	file->private_data = client;
> +
> +	/* We allocate a 1-page buffer, make sure it all fits */
> +	BUILD_BUG_ON((OCC_CMD_DATA_BYTES + 3) > PAGE_SIZE);
> +	BUILD_BUG_ON((OCC_RESP_DATA_BYTES + 7) > PAGE_SIZE);
> +
> +	return 0;
> +}
> +
> +static ssize_t occ_read(struct file *file, char __user *buf, size_t len,
> +			loff_t *offset)
> +{
> +	struct occ_client *client = file->private_data;
> +	ssize_t rc = 0;
> +
> +	if (!client)
> +		return -ENODEV;
> +
> +	if (len > OCC_SRAM_BYTES)
> +		return -EINVAL;
> +
> +	mutex_lock(&client->lock);
> +
> +	/* This should not be possible ... */
> +	if (WARN_ON_ONCE(client->read_offset > client->data_size)) {
> +		rc = -EIO;
> +		goto done;
> +	}
> +
> +	/* Grab how much data we have to read */
> +	rc = min(len, client->data_size - client->read_offset);
> +	if (copy_to_user(buf, client->buffer + client->read_offset, rc))
> +		rc = -EFAULT;
> +	else
> +		client->read_offset += rc;
> +
> + done:
> +	mutex_unlock(&client->lock);
> +
> +	return rc;
> +}
> +
> +static ssize_t occ_write(struct file *file, const char __user *buf,
> +			 size_t len, loff_t *offset)
> +{
> +	struct occ_client *client = file->private_data;
> +	size_t rlen, data_length;
> +	u16 checksum = 0;
> +	ssize_t rc, i;
> +	u8 *cmd;
> +
> +	if (!client)
> +		return -ENODEV;
> +
> +	if (len > (OCC_CMD_DATA_BYTES + 3) || len < 3)
> +		return -EINVAL;
> +
> +	mutex_lock(&client->lock);
> +
> +	/* Construct the command */
> +	cmd = client->buffer;
> +
> +	/* Sequence number (we could increment and compare with response) */
> +	cmd[0] = 1;
> +
> +	/*
> +	 * Copy the user command (assume user data follows the occ command
> +	 * format)
> +	 * byte 0: command type
> +	 * bytes 1-2: data length (msb first)
> +	 * bytes 3-n: data
> +	 */
> +	if (copy_from_user(&cmd[1], buf, len)) {
> +		rc = -EFAULT;
> +		goto done;
> +	}
> +
> +	/* Extract data length */
> +	data_length = (cmd[2] << 8) + cmd[3];
> +	if (data_length > OCC_CMD_DATA_BYTES) {
> +		rc = -EINVAL;
> +		goto done;
> +	}
> +
> +	/* Calculate checksum */
> +	for (i = 0; i < data_length + 4; ++i)
> +		checksum += cmd[i];
> +
> +	cmd[data_length + 4] = checksum >> 8;
> +	cmd[data_length + 5] = checksum & 0xFF;
> +
> +	/* Submit command */
> +	rlen = PAGE_SIZE;
> +	rc = fsi_occ_submit(client->occ->dev, cmd, data_length + 6, cmd,
> +			    &rlen);
> +	if (rc)
> +		goto done;
> +
> +	/* Set read tracking data */
> +	client->data_size = rlen;
> +	client->read_offset = 0;
> +
> +	/* Done */
> +	rc = len;
> +
> + done:
> +	mutex_unlock(&client->lock);
> +
> +	return rc;
> +}
> +
> +static int occ_release(struct inode *inode, struct file *file)
> +{
> +	struct occ_client *client = file->private_data;
> +
> +	free_page((unsigned long)client->buffer);
> +	kfree(client);
> +
> +	return 0;
> +}
> +
> +static const struct file_operations occ_fops = {
> +	.owner = THIS_MODULE,
> +	.open = occ_open,
> +	.read = occ_read,
> +	.write = occ_write,
> +	.release = occ_release,
> +};
> +
> +static int occ_verify_checksum(struct occ_response *resp, u16 data_length)
> +{
> +	/* Fetch the two bytes after the data for the checksum. */
> +	u16 checksum_resp = get_unaligned_be16(&resp->data[data_length]);
> +	u16 checksum;
> +	u16 i;
> +
> +	checksum = resp->seq_no;
> +	checksum += resp->cmd_type;
> +	checksum += resp->return_status;
> +	checksum += (data_length >> 8) + (data_length & 0xFF);
> +
> +	for (i = 0; i < data_length; ++i)
> +		checksum += resp->data[i];
> +
> +	if (checksum != checksum_resp)
> +		return -EBADMSG;
> +
> +	return 0;
> +}
> +
> +static int occ_getsram(struct occ *occ, u32 address, void *data, ssize_t len)
> +{
> +	u32 data_len = ((len + 7) / 8) * 8;	/* must be multiples of 8 B */
> +	size_t resp_len, resp_data_len;
> +	__be32 *resp, cmd[5];
> +	int rc;
> +
> +	/*
> +	 * Magic sequence to do SBE getsram command. SBE will fetch data from
> +	 * specified SRAM address.
> +	 */
> +	cmd[0] = cpu_to_be32(0x5);
> +	cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_OCC_SRAM);
> +	cmd[2] = cpu_to_be32(1);
> +	cmd[3] = cpu_to_be32(address);
> +	cmd[4] = cpu_to_be32(data_len);
> +
> +	resp_len = (data_len >> 2) + OCC_SBE_STATUS_WORDS;
> +	resp = kzalloc(resp_len << 2, GFP_KERNEL);
> +	if (!resp)
> +		return -ENOMEM;
> +
> +	rc = sbefifo_submit(occ->sbefifo, cmd, 5, resp, &resp_len);
> +	if (rc)
> +		goto free;
> +
> +	rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_GET_OCC_SRAM,
> +				  resp, resp_len, &resp_len);
> +	if (rc)
> +		goto free;
> +
> +	resp_data_len = be32_to_cpu(resp[resp_len - 1]);
> +	if (resp_data_len != data_len) {
> +		dev_err(occ->dev, "SRAM read expected %d bytes got %zd\n",
> +			data_len, resp_data_len);
> +		rc = -EBADMSG;
> +	} else {
> +		memcpy(data, resp, len);
> +	}
> +
> +free:
> +	/* Convert positive SBEI status */
> +	if (rc > 0) {
> +		dev_err(occ->dev, "SRAM read returned failure status: %08x\n",
> +			rc);
> +		rc = -EBADMSG;
> +	}
> +
> +	kfree(resp);
> +	return rc;
> +}
> +
> +static int occ_putsram(struct occ *occ, u32 address, const void *data,
> +		       ssize_t len)
> +{
> +	size_t cmd_len, buf_len, resp_len, resp_data_len;
> +	u32 data_len = ((len + 7) / 8) * 8;	/* must be multiples of 8 B */
> +	__be32 *buf;
> +	int rc;
> +
> +	/*
> +	 * We use the same buffer for command and response, make
> +	 * sure it's big enough
> +	 */
> +	resp_len = OCC_SBE_STATUS_WORDS;
> +	cmd_len = (data_len >> 2) + 5;
> +	buf_len = max(cmd_len, resp_len);
> +	buf = kzalloc(buf_len << 2, GFP_KERNEL);
> +	if (!buf)
> +		return -ENOMEM;
> +
> +	/*
> +	 * Magic sequence to do SBE putsram command. SBE will transfer
> +	 * data to specified SRAM address.
> +	 */
> +	buf[0] = cpu_to_be32(cmd_len);
> +	buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
> +	buf[2] = cpu_to_be32(1);
> +	buf[3] = cpu_to_be32(address);
> +	buf[4] = cpu_to_be32(data_len);
> +
> +	memcpy(&buf[5], data, len);
> +
> +	rc = sbefifo_submit(occ->sbefifo, buf, cmd_len, buf, &resp_len);
> +	if (rc)
> +		goto free;
> +
> +	rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
> +				  buf, resp_len, &resp_len);
> +	if (rc)
> +		goto free;
> +
> +	if (resp_len != 1) {
> +		dev_err(occ->dev, "SRAM write response length invalid: %zd\n",
> +			resp_len);
> +		rc = -EBADMSG;
> +	} else {
> +		resp_data_len = be32_to_cpu(buf[0]);
> +		if (resp_data_len != data_len) {
> +			dev_err(occ->dev,
> +				"SRAM write expected %d bytes got %zd\n",
> +				data_len, resp_data_len);
> +			rc = -EBADMSG;
> +		}
> +	}
> +
> +free:
> +	/* Convert positive SBEI status */
> +	if (rc > 0) {
> +		dev_err(occ->dev, "SRAM write returned failure status: %08x\n",
> +			rc);
> +		rc = -EBADMSG;
> +	}
> +
> +	kfree(buf);
> +	return rc;
> +}
> +
> +static int occ_trigger_attn(struct occ *occ)
> +{
> +	__be32 buf[OCC_SBE_STATUS_WORDS];
> +	size_t resp_len, resp_data_len;
> +	int rc;
> +
> +	BUILD_BUG_ON(OCC_SBE_STATUS_WORDS < 7);
> +	resp_len = OCC_SBE_STATUS_WORDS;
> +
> +	buf[0] = cpu_to_be32(0x5 + 0x2);        /* Chip-op length in words */
> +	buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
> +	buf[2] = cpu_to_be32(0x3);              /* Mode: Circular */
> +	buf[3] = cpu_to_be32(0x0);              /* Address: ignore in mode 3 */
> +	buf[4] = cpu_to_be32(0x8);              /* Data length in bytes */
> +	buf[5] = cpu_to_be32(0x20010000);       /* Trigger OCC attention */
> +	buf[6] = 0;
> +
> +	rc = sbefifo_submit(occ->sbefifo, buf, 7, buf, &resp_len);
> +	if (rc)
> +		goto error;
> +
> +	rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
> +				  buf, resp_len, &resp_len);
> +	if (rc)
> +		goto error;
> +
> +	if (resp_len != 1) {
> +		dev_err(occ->dev, "SRAM attn response length invalid: %zd\n",
> +			resp_len);
> +		rc = -EBADMSG;
> +	} else {
> +		resp_data_len = be32_to_cpu(buf[0]);
> +		if (resp_data_len != 8) {
> +			dev_err(occ->dev,
> +				"SRAM attn expected 8 bytes got %zd\n",
> +				resp_data_len);
> +			rc = -EBADMSG;
> +		}
> +	}
> +
> + error:
> +	/* Convert positive SBEI status */
> +	if (rc > 0) {
> +		dev_err(occ->dev, "SRAM attn returned failure status: %08x\n",
> +			rc);
> +		rc = -EBADMSG;
> +	}
> +
> +	return rc;
> +}
> +
> +int fsi_occ_submit(struct device *dev, const void *request, size_t req_len,
> +		   void *response, size_t *resp_len)
> +{
> +	const unsigned long timeout = msecs_to_jiffies(OCC_TIMEOUT_MS);
> +	const unsigned long wait_time =
> +		msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS);
> +	struct occ *occ = dev_get_drvdata(dev);
> +	struct occ_response *resp = response;
> +	u16 resp_data_length;
> +	unsigned long start;
> +	int rc;
> +
> +	if (!occ)
> +		return -ENODEV;
> +
> +	if (*resp_len < 7) {
> +		dev_dbg(dev, "Bad resplen %zd\n", *resp_len);
> +		return -EINVAL;
> +	}
> +
> +	mutex_lock(&occ->occ_lock);
> +
> +	rc = occ_putsram(occ, OCC_SRAM_CMD_ADDR, request, req_len);
> +	if (rc)
> +		goto done;
> +
> +	rc = occ_trigger_attn(occ);
> +	if (rc)
> +		goto done;
> +
> +	/* Read occ response header */
> +	start = jiffies;
> +	do {
> +		rc = occ_getsram(occ, OCC_SRAM_RSP_ADDR, resp, 8);
> +		if (rc)
> +			goto done;
> +
> +		if (resp->return_status == OCC_RESP_CMD_IN_PRG) {
> +			rc = -ETIMEDOUT;
> +
> +			if (time_after(jiffies, start + timeout))
> +				break;
> +
> +			set_current_state(TASK_UNINTERRUPTIBLE);
> +			schedule_timeout(wait_time);
> +		}
> +	} while (rc);
> +
> +	/* Extract size of response data */
> +	resp_data_length = get_unaligned_be16(&resp->data_length);
> +
> +	/* Message size is data length + 5 bytes header + 2 bytes checksum */
> +	if ((resp_data_length + 7) > *resp_len) {
> +		rc = -EMSGSIZE;
> +		goto done;
> +	}
> +
> +	dev_dbg(dev, "resp_status=%02x resp_data_len=%d\n",
> +		resp->return_status, resp_data_length);
> +
> +	/* Grab the rest */
> +	if (resp_data_length > 1) {
> +		/* already got 3 bytes resp, also need 2 bytes checksum */
> +		rc = occ_getsram(occ, OCC_SRAM_RSP_ADDR + 8,
> +				 &resp->data[3], resp_data_length - 1);
> +		if (rc)
> +			goto done;
> +	}
> +
> +	*resp_len = resp_data_length + 7;
> +	rc = occ_verify_checksum(resp, resp_data_length);
> +
> + done:
> +	mutex_unlock(&occ->occ_lock);
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL_GPL(fsi_occ_submit);
> +
> +static int occ_unregister_child(struct device *dev, void *data)
> +{
> +	struct platform_device *hwmon_dev = to_platform_device(dev);
> +
> +	platform_device_unregister(hwmon_dev);
> +
> +	return 0;
> +}
> +
> +static int occ_probe(struct platform_device *pdev)
> +{
> +	int rc;
> +	u32 reg;
> +	struct occ *occ;
> +	struct platform_device *hwmon_dev;
> +	struct device *dev = &pdev->dev;
> +	struct platform_device_info hwmon_dev_info = {
> +		.parent = dev,
> +		.name = "occ-hwmon",
> +	};
> +
> +	occ = devm_kzalloc(dev, sizeof(*occ), GFP_KERNEL);
> +	if (!occ)
> +		return -ENOMEM;
> +
> +	occ->dev = dev;
> +	occ->sbefifo = dev->parent;
> +	mutex_init(&occ->occ_lock);
> +
> +	if (dev->of_node) {
> +		rc = of_property_read_u32(dev->of_node, "reg", &reg);
> +		if (!rc) {
> +			/* make sure we don't have a duplicate from dts */
> +			occ->idx = ida_simple_get(&occ_ida, reg, reg + 1,
> +						  GFP_KERNEL);
> +			if (occ->idx < 0)
> +				occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
> +							  GFP_KERNEL);
> +		} else {
> +			occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
> +						  GFP_KERNEL);
> +		}
> +	} else {
> +		occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, GFP_KERNEL);
> +	}
> +
> +	platform_set_drvdata(pdev, occ);
> +
> +	snprintf(occ->name, sizeof(occ->name), "occ%d", occ->idx);
> +	occ->mdev.fops = &occ_fops;
> +	occ->mdev.minor = MISC_DYNAMIC_MINOR;
> +	occ->mdev.name = occ->name;
> +	occ->mdev.parent = dev;
> +
> +	rc = misc_register(&occ->mdev);
> +	if (rc) {
> +		dev_err(dev, "failed to register miscdevice: %d\n", rc);
> +		ida_simple_remove(&occ_ida, occ->idx);
> +		return rc;
> +	}
> +
> +	hwmon_dev_info.id = occ->idx;
> +	hwmon_dev = platform_device_register_full(&hwmon_dev_info);
> +	if (!hwmon_dev)
> +		dev_warn(dev, "failed to create hwmon device\n");
> +

Not my call to make, but since you are using devicetree I would have
thought it would be possible to use something like of_platform_populate()
to register child drivers.

> +	return 0;
> +}
> +
> +static int occ_remove(struct platform_device *pdev)
> +{
> +	struct occ *occ = platform_get_drvdata(pdev);
> +
> +	misc_deregister(&occ->mdev);
> +
> +	device_for_each_child(&pdev->dev, NULL, occ_unregister_child);
> +
> +	ida_simple_remove(&occ_ida, occ->idx);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id occ_match[] = {
> +	{ .compatible = "ibm,p9-occ" },
> +	{ },
> +};
> +
> +static struct platform_driver occ_driver = {
> +	.driver = {
> +		.name = "occ",
> +		.of_match_table	= occ_match,
> +	},
> +	.probe	= occ_probe,
> +	.remove = occ_remove,
> +};
> +
> +static int occ_init(void)
> +{
> +	return platform_driver_register(&occ_driver);
> +}
> +
> +static void occ_exit(void)
> +{
> +	platform_driver_unregister(&occ_driver);
> +
> +	ida_destroy(&occ_ida);
> +}
> +
> +module_init(occ_init);
> +module_exit(occ_exit);
> +
> +MODULE_AUTHOR("Eddie James <eajames@linux.vnet.ibm.com>");
> +MODULE_DESCRIPTION("BMC P9 OCC driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/fsi-occ.h b/include/linux/fsi-occ.h
> new file mode 100644
> index 0000000..e28cf9a
> --- /dev/null
> +++ b/include/linux/fsi-occ.h
> @@ -0,0 +1,34 @@
> +/*
> + * On-Chip Controller Driver definitions and prototypes
> + *
> + * Copyright (C) IBM Corporation 2018
> + *
> + * 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.
> + */
> +
> +#ifndef LINUX_FSI_OCC_H
> +#define LINUX_FSI_OCC_H
> +
> +struct device;
> +
> +#define OCC_RESP_CMD_IN_PRG		0xFF
> +#define OCC_RESP_SUCCESS		0
> +#define OCC_RESP_CMD_INVAL		0x11
> +#define OCC_RESP_CMD_LEN_INVAL		0x12
> +#define OCC_RESP_DATA_INVAL		0x13
> +#define OCC_RESP_CHKSUM_ERR		0x14
> +#define OCC_RESP_INT_ERR		0x15
> +#define OCC_RESP_BAD_STATE		0x16
> +#define OCC_RESP_CRIT_EXCEPT		0xE0
> +#define OCC_RESP_CRIT_INIT		0xE1
> +#define OCC_RESP_CRIT_WATCHDOG		0xE2
> +#define OCC_RESP_CRIT_OCB		0xE3
> +#define OCC_RESP_CRIT_HW		0xE4
> +
> +int fsi_occ_submit(struct device *dev, const void *request, size_t req_len,
> +		   void *response, size_t *resp_len);
> +
> +#endif /* LINUX_FSI_OCC_H */