[PATCH linux v9 0/5] drivers: hwmon: Add On-Chip Controller driver

[PATCH linux v9 0/5] drivers: hwmon: Add On-Chip Controller driver

[Eddie James]

From: "Edward A. James" <eajames@us.ibm.com>

This patchset adds a hwmon driver to support 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.

The driver provides an interface on a BMC to poll OCC sensor data, set
user power caps, and perform some basic OCC error handling. It interfaces
with userspace through hwmon.

The driver is currently functional only for the OCC on POWER8 chips.
Communicating with the POWER9 OCC requries FSI support.

since v8:
 * drop P9 sensors patch. This patch was mainly included to demonstrate
why we abstracted out the sensor-specific code into the occ_p8 functions.
However, since we haven't submitted the transfer protocol to the OCC for
P9 yet, we shouldn't submit this unused P9 code yet.
 * fix string access in hwmon read_string() function. Thanks Guenter.
 * change parameter to const char ** in read_string() function to match
upcoming hwmon code.

Edward A. James (5):
  hwmon: Add core On-Chip Controller support for POWER CPUs
  hwmon: occ: Add sysfs interface
  hwmon: occ: Add I2C transport implementation for SCOM operations
  hwmon: occ: Add callbacks for parsing P8 OCC datastructures
  hwmon: occ: Add hwmon implementation for the P8 OCC

 Documentation/devicetree/bindings/hwmon/occ.txt |  13 +
 Documentation/hwmon/occ                         | 113 ++++++
 MAINTAINERS                                     |   7 +
 drivers/hwmon/Kconfig                           |   2 +
 drivers/hwmon/Makefile                          |   1 +
 drivers/hwmon/occ/Kconfig                       |  28 ++
 drivers/hwmon/occ/Makefile                      |   3 +
 drivers/hwmon/occ/occ.c                         | 440 ++++++++++++++++++++++++
 drivers/hwmon/occ/occ.h                         |  77 +++++
 drivers/hwmon/occ/occ_p8.c                      | 256 ++++++++++++++
 drivers/hwmon/occ/occ_p8.h                      |  25 ++
 drivers/hwmon/occ/occ_p8_i2c.c                  |  99 ++++++
 drivers/hwmon/occ/occ_scom_i2c.c                |  69 ++++
 drivers/hwmon/occ/occ_scom_i2c.h                |  21 ++
 drivers/hwmon/occ/occ_sysfs.c                   | 253 ++++++++++++++
 drivers/hwmon/occ/occ_sysfs.h                   |  25 ++
 drivers/hwmon/occ/scom.h                        |  42 +++
 17 files changed, 1474 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/occ.txt
 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/occ_p8.c
 create mode 100644 drivers/hwmon/occ/occ_p8.h
 create mode 100644 drivers/hwmon/occ/occ_p8_i2c.c
 create mode 100644 drivers/hwmon/occ/occ_scom_i2c.c
 create mode 100644 drivers/hwmon/occ/occ_scom_i2c.h
 create mode 100644 drivers/hwmon/occ/occ_sysfs.c
 create mode 100644 drivers/hwmon/occ/occ_sysfs.h
 create mode 100644 drivers/hwmon/occ/scom.h

-- 
1.8.3.1

[PATCH linux v9 1/5] hwmon: Add core On-Chip Controller support for POWER CPUs

[Eddie James]

From: "Edward A. James" <eajames@us.ibm.com>

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@us.ibm.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 Documentation/hwmon/occ    |  42 +++++
 MAINTAINERS                |   7 +
 drivers/hwmon/Kconfig      |   2 +
 drivers/hwmon/Makefile     |   1 +
 drivers/hwmon/occ/Kconfig  |  13 ++
 drivers/hwmon/occ/Makefile |   1 +
 drivers/hwmon/occ/occ.c    | 440 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/hwmon/occ/occ.h    |  77 ++++++++
 drivers/hwmon/occ/scom.h   |  42 +++++
 9 files changed, 625 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..d1c863b
--- /dev/null
+++ b/Documentation/hwmon/occ
@@ -0,0 +1,42 @@
+=================
+Kernel driver occ
+=================
+
+Supported chips:
+ * POWER8
+ * POWER9
+
+Please note that the driver does not run on these processors. Instead, the
+driver runs on a connected service processor, such as an AST2400. (see the
+BMC - Host Communications section).
+
+Author: Eddie James <eajames@us.ibm.com>
+
+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 c776906..4e929fc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9266,6 +9266,13 @@ T:	git git://linuxtv.org/media_tree.git
 S:	Maintained
 F:	drivers/media/i2c/ov7670.c
 
+ON-CHIP CONTROLLER HWMON POWER8/POWER9 DRIVER
+M:	Eddie James <eajames@us.ibm.com>
+L:	openbmc@lists.ozlabs.org
+S:	Maintained
+F:	Documentation/hwmon/occ
+F:	drivers/hwmon/occ/
+
 ONENAND FLASH DRIVER
 M:	Kyungmin Park <kyungmin.park@samsung.com>
 L:	linux-mtd@lists.infradead.org
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 0649d53f3..6589933 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 5509edf..5b26067 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -170,6 +170,7 @@ obj-$(CONFIG_SENSORS_WM831X)	+= wm831x-hwmon.o
 obj-$(CONFIG_SENSORS_WM8350)	+= wm8350-hwmon.o
 obj-$(CONFIG_SENSORS_XGENE)	+= xgene-hwmon.o
 
+obj-$(CONFIG_SENSORS_IBM_OCC)	+= occ/
 obj-$(CONFIG_PMBUS)		+= pmbus/
 
 ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG
diff --git a/drivers/hwmon/occ/Kconfig b/drivers/hwmon/occ/Kconfig
new file mode 100644
index 0000000..61be588
--- /dev/null
+++ b/drivers/hwmon/occ/Kconfig
@@ -0,0 +1,13 @@
+#
+# On Chip Controller configuration
+#
+
+menuconfig SENSORS_IBM_OCC
+	bool "IBM On-Chip Controller"
+	help
+	  If you say yes here you get support to monitor IBM Power CPU
+	  sensors via the On-Chip Controller (OCC), from a service
+	  processor.
+
+	  Generally this is used by management controllers such as a BMC
+	  on an OpenPower system.
diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
new file mode 100644
index 0000000..3ed79a5
--- /dev/null
+++ b/drivers/hwmon/occ/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o
diff --git a/drivers/hwmon/occ/occ.c b/drivers/hwmon/occ/occ.c
new file mode 100644
index 0000000..afc21f8
--- /dev/null
+++ b/drivers/hwmon/occ/occ.c
@@ -0,0 +1,440 @@
+/*
+ * occ.c - OCC hwmon driver
+ *
+ * This file contains the methods and data structures for the OCC hwmon driver.
+ *
+ * Copyright 2017 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.
+ */
+
+#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;
+	u32 command_addr;
+	u32 response_addr;
+	unsigned long last_updated;
+	struct mutex update_lock;
+	struct occ_response response;
+	bool valid;
+	u8 *raw_data;
+};
+
+static int parse_occ_response(struct occ *driver, u16 num_bytes)
+{
+	int b;
+	int s;
+	unsigned int offset = SENSOR_BLOCK_OFFSET;
+	int sensor_type;
+	u8 num_sensor_blocks;
+	struct sensor_data_block_header *block;
+	void *sensors;
+	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");
+		return -ENODATA;
+	}
+
+	num_sensor_blocks = data[NUM_SENSOR_BLOCKS_OFFSET];
+	if (num_sensor_blocks == 0) {
+		dev_warn(dev, "no sensor blocks available\n");
+		return -ENODATA;
+	}
+
+	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");
+			return 0;
+		}
+
+		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;
+		}
+
+		sensors = &resp->data.blocks[b].sensors;
+		if (!sensors) {
+			/* first poll response */
+			sensors = driver->ops.alloc_sensor(dev, sensor_type,
+							   block->num_sensors);
+			if (!sensors)
+				return -ENOMEM;
+
+			resp->data.blocks[b].sensors = sensors;
+			resp->data.sensor_block_id[sensor_type] = b;
+			resp->data.blocks[b].header = *block;
+		} else if (block->sensor_length !=
+			 resp->data.blocks[b].header.sensor_length) {
+			dev_warn(dev,
+				 "different sensor length than first poll\n");
+			continue;
+		}
+
+		for (s = 0; s < block->num_sensors &&
+		     s < resp->data.blocks[b].header.num_sensors; s++) {
+			if (offset + block->sensor_length > num_bytes) {
+				dev_warn(dev, "exceeded data length\n");
+				return 0;
+			}
+
+			driver->ops.parse_sensor(data, sensors, sensor_type,
+						 offset, s);
+			offset += block->sensor_length;
+		}
+	}
+
+	return 0;
+}
+
+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, the on-chip bridge interface */
+	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->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->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)
+		return rc;
+
+	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);
+		return -EINVAL;
+	}
+
+	/* 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);
+			return rc;
+		}
+	}
+
+	/* 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);
+
+	return rc;
+}
+
+int occ_update_device(struct occ *driver)
+{
+	int rc = 0;
+
+	mutex_lock(&driver->update_lock);
+
+	if (time_after(jiffies, driver->last_updated + HZ) || !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;
+}
+
+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 ERR_PTR(rc);
+
+	type_id = driver->response.data.sensor_block_id[sensor_type];
+	if (type_id == -1)
+		return ERR_PTR(-ENODATA);
+
+	return driver->response.data.blocks[type_id].sensors;
+}
+
+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);
+}
+
+void occ_get_response_blocks(struct occ *occ, struct occ_blocks **blocks)
+{
+	*blocks = &occ->response.data;
+}
+
+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);
+}
+
+struct occ *occ_init(struct device *dev, void *bus,
+		     const struct occ_bus_ops *bus_ops,
+		     const struct occ_init_data *init)
+{
+	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 = *init->ops;
+	driver->command_addr = init->command_addr;
+	driver->response_addr = init->response_addr;
+
+	driver->raw_data = devm_kzalloc(dev, OCC_DATA_MAX, GFP_KERNEL);
+	if (!driver->raw_data)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&driver->update_lock);
+
+	return driver;
+}
+
+MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>");
+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..6732843
--- /dev/null
+++ b/drivers/hwmon/occ/occ.h
@@ -0,0 +1,77 @@
+/*
+ * occ.h - hwmon OCC driver
+ *
+ * This file contains data structures and function prototypes for common access
+ * between different bus protocols and host systems.
+ *
+ * Copyright 2017 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.
+ */
+
+#ifndef __OCC_H__
+#define __OCC_H__
+
+#include "scom.h"
+
+struct device;
+struct occ;
+
+enum sensor_type {
+	FREQ = 0,
+	TEMP,
+	POWER,
+	CAPS,
+	MAX_OCC_SENSOR_TYPE
+};
+
+/* 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;
+};
+
+struct occ_blocks {
+	int sensor_block_id[MAX_OCC_SENSOR_TYPE];
+	struct sensor_data_block blocks[MAX_OCC_SENSOR_TYPE];
+};
+
+struct occ_ops {
+	void (*parse_sensor)(u8 *data, void *sensor, int sensor_type, int off,
+			     int snum);
+	void *(*alloc_sensor)(struct device *dev, int sensor_type,
+			      int num_sensors);
+	int (*get_sensor)(struct occ *driver, int sensor_type, int sensor_num,
+			  u32 hwmon, long *val);
+};
+
+struct occ_init_data {
+	u32 command_addr;
+	u32 response_addr;
+	const struct occ_ops *ops;
+};
+
+struct occ *occ_init(struct device *dev, void *bus,
+		     const struct occ_bus_ops *bus_ops,
+		     const struct occ_init_data *init);
+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..4a891c4
--- /dev/null
+++ b/drivers/hwmon/occ/scom.h
@@ -0,0 +1,42 @@
+/*
+ * scom.h - hwmon OCC driver
+ *
+ * This file contains data structures for scom operations to the OCC
+ *
+ * Copyright 2017 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.
+ */
+
+#ifndef __SCOM_H__
+#define __SCOM_H__
+
+/*
+ * occ_bus_ops - represent the low-level transfer methods to communicate with
+ * the OCC.
+ *
+ * getscom - OCC scom read 8 bytes
+ * @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__ */
-- 
1.8.3.1

[PATCH linux v9 2/5] hwmon: occ: Add sysfs interface

[Eddie James]

From: "Edward A. James" <eajames@us.ibm.com>

Add a generic mechanism to expose the sensors provided by the OCC in
sysfs.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 Documentation/hwmon/occ       |  62 +++++++++++
 drivers/hwmon/occ/Makefile    |   2 +-
 drivers/hwmon/occ/occ_sysfs.c | 253 ++++++++++++++++++++++++++++++++++++++++++
 drivers/hwmon/occ/occ_sysfs.h |  25 +++++
 4 files changed, 341 insertions(+), 1 deletion(-)
 create mode 100644 drivers/hwmon/occ/occ_sysfs.c
 create mode 100644 drivers/hwmon/occ/occ_sysfs.h

diff --git a/Documentation/hwmon/occ b/Documentation/hwmon/occ
index d1c863b..580af26 100644
--- a/Documentation/hwmon/occ
+++ b/Documentation/hwmon/occ
@@ -27,6 +27,68 @@ 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.
 
+sysfs Entries
+-------------
+
+The OCC driver uses the hwmon sysfs framework to provide data to userspace.
+
+The driver exports a number of sysfs files for each type of sensor. The
+sensor-specific files vary depending on the processor type, though many of the
+attributes are common for both the POWER8 and POWER9.
+
+The hwmon interface cannot define every type of sensor that may be used.
+Therefore, the frequency sensor on the OCC uses the "input" type sensor defined
+by the hwmon interface, rather than defining a new type of custom sensor.
+
+Below are detailed the names and meaning of each sensor file for both types of
+processors. All sensors are read-only unless otherwise specified. <x> indicates
+the hwmon index. sensor id indicates the unique internal OCC identifer. Please
+see the POWER OCC specification for details on all these sensor values.
+
+frequency:
+	all processors:
+		in<x>_input - frequency value
+		in<x>_label - sensor id
+temperature:
+	POWER8:
+		temp<x>_input - temperature value
+		temp<x>_label - sensor id
+	POWER9 (in addition to above):
+		temp<x>_type - FRU type
+
+power:
+	POWER8:
+		power<x>_input - power value
+		power<x>_label - sensor id
+		power<x>_average - accumulator
+		power<x>_average_interval - update tag (number of samples in
+			accumulator)
+	POWER9:
+		power<x>_input - power value
+		power<x>_label - sensor id
+		power<x>_average_min - accumulator[0]
+		power<x>_average_max - accumulator[1] (64 bits total)
+		power<x>_average_interval - update tag
+		power<x>_reset_history - (function_id | (apss_channel << 8)
+
+caps:
+	POWER8:
+		power<x>_cap - current powercap
+		power<x>_cap_max - max powercap
+		power<x>_cap_min - min powercap
+		power<x>_max - normal powercap
+		power<x>_alarm - user powercap, r/w
+	POWER9:
+		power<x>_cap_alarm - user powercap source
+
+The driver also provides two sysfs entries through hwmon to better
+control the driver and monitor the master OCC. Though there may be multiple
+OCCs present on the system, these two files are only present for the "master"
+OCC.
+	name - read the name of the driver
+	update_interval - read or write the minimum interval for polling the
+		OCC.
+
 BMC - Host Communications
 -------------------------
 
diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
index 3ed79a5..67b5367 100644
--- a/drivers/hwmon/occ/Makefile
+++ b/drivers/hwmon/occ/Makefile
@@ -1 +1 @@
-obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o
+obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o occ_sysfs.o
diff --git a/drivers/hwmon/occ/occ_sysfs.c b/drivers/hwmon/occ/occ_sysfs.c
new file mode 100644
index 0000000..50b20e2
--- /dev/null
+++ b/drivers/hwmon/occ/occ_sysfs.c
@@ -0,0 +1,253 @@
+/*
+ * occ_sysfs.c - OCC sysfs interface
+ *
+ * This file contains the methods and data structures for implementing the OCC
+ * hwmon sysfs entries.
+ *
+ * Copyright 2017 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.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.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"
+#include "occ_sysfs.h"
+
+#define OCC_HWMON_NAME_LENGTH	32
+
+struct occ_sysfs {
+	struct device *dev;
+	struct occ *occ;
+
+	char label_buffer[OCC_HWMON_NAME_LENGTH + 1];
+	char hwmon_name[OCC_HWMON_NAME_LENGTH + 1];
+	const u32 *sensor_hwmon_configs;
+	struct hwmon_channel_info **occ_sensors;
+	struct hwmon_chip_info occ_info;
+	u16 user_powercap;
+};
+
+static int occ_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+			  u32 attr, int channel, long *val)
+{
+	int rc;
+	struct occ_sysfs *driver = dev_get_drvdata(dev);
+	struct occ *occ = driver->occ;
+
+	switch (type) {
+	case hwmon_in:
+		rc = occ_get_sensor_field(occ, FREQ, channel, attr, val);
+		break;
+	case hwmon_temp:
+		rc = occ_get_sensor_field(occ, TEMP, channel, attr, val);
+		break;
+	case hwmon_power:
+		rc = occ_get_sensor_field(occ, POWER, channel, attr, val);
+		break;
+	default:
+		rc = -EOPNOTSUPP;
+	}
+
+	return rc;
+}
+
+static int occ_hwmon_read_string(struct device *dev,
+				 enum hwmon_sensor_types type, u32 attr,
+				 int channel, const char **str)
+{
+	int rc;
+	unsigned long val = 0;
+	struct occ_sysfs *driver = dev_get_drvdata(dev);
+
+	if (!((type == hwmon_in && attr == hwmon_in_label) ||
+	    (type == hwmon_temp && attr == hwmon_temp_label) ||
+	    (type == hwmon_power && attr == hwmon_power_label)))
+		return -EOPNOTSUPP;
+
+	/* will fetch the "label", the sensor_id */
+	rc = occ_hwmon_read(dev, type, attr, channel, &val);
+	if (rc < 0)
+		return rc;
+
+	/* just use one label buffer for all sensors. works with current hwmon
+	 * implementation. only alternative is to store a buffer for each
+	 * sensor, which gets expensive quickly.
+	 */
+	rc = snprintf(driver->label_buffer, OCC_HWMON_NAME_LENGTH, "%lu", val);
+	if (rc > 0)
+		rc = 0;
+
+	*str = driver->label_buffer;
+
+	return rc;
+}
+
+static int occ_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
+			   u32 attr, int channel, long val)
+{
+	int rc;
+	struct occ_sysfs *driver = dev_get_drvdata(dev);
+
+	if (type == hwmon_power && attr == hwmon_power_alarm) {
+		rc = occ_set_user_powercap(driver->occ, val);
+		if (rc) {
+			dev_err(dev, "set user powercap failed:%d\n", rc);
+			return rc;
+		}
+
+		driver->user_powercap = val;
+
+		return rc;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static umode_t occ_is_visible(const void *data, enum hwmon_sensor_types type,
+			      u32 attr, int channel)
+{
+	const struct occ_sysfs *driver = data;
+
+	switch (type) {
+	case hwmon_chip:
+		if (attr == hwmon_chip_update_interval)
+			return 0644;
+		break;
+	case hwmon_in:
+		if (BIT(attr) & driver->sensor_hwmon_configs[0])
+			return 0444;
+		break;
+	case hwmon_temp:
+		if (BIT(attr) & driver->sensor_hwmon_configs[1])
+			return 0444;
+		break;
+	case hwmon_power:
+		/* user power limit */
+		if (attr == hwmon_power_alarm)
+			return 0644;
+		else if ((BIT(attr) & driver->sensor_hwmon_configs[2]) ||
+			 (BIT(attr) & driver->sensor_hwmon_configs[3]))
+			return 0444;
+		break;
+	default:
+		return 0;
+	}
+
+	return 0;
+}
+
+static const struct hwmon_ops occ_hwmon_ops = {
+	.is_visible = occ_is_visible,
+	.read = occ_hwmon_read,
+	.read_string = occ_hwmon_read_string,
+	.write = occ_hwmon_write,
+};
+
+static const enum hwmon_sensor_types occ_sensor_types[MAX_OCC_SENSOR_TYPE] = {
+	hwmon_in,
+	hwmon_temp,
+	hwmon_power,
+	hwmon_power
+};
+
+struct occ_sysfs *occ_sysfs_start(struct device *dev, struct occ *occ,
+				  const u32 *sensor_hwmon_configs,
+				  const char *name)
+{
+	int rc, i, j, num_sensors, index = 0, id;
+	char *brk;
+	struct occ_blocks *resp = NULL;
+	u32 *sensor_config;
+	struct occ_sysfs *hwmon = devm_kzalloc(dev, sizeof(struct occ_sysfs),
+					       GFP_KERNEL);
+	if (!hwmon)
+		return ERR_PTR(-ENOMEM);
+
+	/* need space for null-termination */
+	hwmon->occ_sensors =
+		devm_kzalloc(dev, sizeof(struct hwmon_channel_info *) *
+			     (MAX_OCC_SENSOR_TYPE + 1), GFP_KERNEL);
+	if (!hwmon->occ_sensors)
+		return ERR_PTR(-ENOMEM);
+
+	hwmon->occ = occ;
+	hwmon->sensor_hwmon_configs = sensor_hwmon_configs;
+	hwmon->occ_info.ops = &occ_hwmon_ops;
+	hwmon->occ_info.info =
+		(const struct hwmon_channel_info **)hwmon->occ_sensors;
+
+	occ_get_response_blocks(occ, &resp);
+
+	for (i = 0; i < MAX_OCC_SENSOR_TYPE; ++i)
+		resp->sensor_block_id[i] = -1;
+
+	/* read sensor data from occ */
+	rc = occ_update_device(occ);
+	if (rc)
+		return ERR_PTR(rc);
+
+	for (i = 0; i < MAX_OCC_SENSOR_TYPE; i++) {
+		id = resp->sensor_block_id[i];
+		if (id < 0)
+			continue;
+
+		num_sensors = resp->blocks[id].header.num_sensors;
+		/* need null-termination */
+		sensor_config = devm_kzalloc(dev,
+					     sizeof(u32) * (num_sensors + 1),
+					     GFP_KERNEL);
+		if (!sensor_config)
+			return ERR_PTR(-ENOMEM);
+
+		for (j = 0; j < num_sensors; j++)
+			sensor_config[j] = sensor_hwmon_configs[i];
+
+		hwmon->occ_sensors[index] =
+			devm_kzalloc(dev, sizeof(struct hwmon_channel_info),
+				     GFP_KERNEL);
+		if (!hwmon->occ_sensors[index])
+			return ERR_PTR(-ENOMEM);
+
+		hwmon->occ_sensors[index]->type = occ_sensor_types[i];
+		hwmon->occ_sensors[index]->config = sensor_config;
+		index++;
+	}
+
+	/* search for bad chars */
+	strncpy(hwmon->hwmon_name, name, OCC_HWMON_NAME_LENGTH);
+	brk = strpbrk(hwmon->hwmon_name, "-* \t\n");
+	while (brk) {
+		*brk = '_';
+		brk = strpbrk(brk,  "-* \t\n");
+	}
+
+	hwmon->dev = devm_hwmon_device_register_with_info(dev,
+							  hwmon->hwmon_name,
+							  hwmon,
+							  &hwmon->occ_info,
+							  NULL);
+	if (IS_ERR(hwmon->dev)) {
+		dev_err(dev, "cannot register hwmon device %s: %ld\n",
+			hwmon->hwmon_name, PTR_ERR(hwmon->dev));
+		return ERR_CAST(hwmon->dev);
+	}
+
+	return hwmon;
+}
+
+MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>");
+MODULE_DESCRIPTION("OCC sysfs driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hwmon/occ/occ_sysfs.h b/drivers/hwmon/occ/occ_sysfs.h
new file mode 100644
index 0000000..fcd4f59a
--- /dev/null
+++ b/drivers/hwmon/occ/occ_sysfs.h
@@ -0,0 +1,25 @@
+/*
+ * occ_sysfs.h - OCC sysfs interface
+ *
+ * This file contains the data structures and function prototypes for the OCC
+ * hwmon sysfs entries.
+ *
+ * Copyright 2017 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.
+ */
+
+#ifndef __OCC_SYSFS_H__
+#define __OCC_SYSFS_H__
+
+struct occ;
+struct device;
+struct occ_sysfs;
+
+struct occ_sysfs *occ_sysfs_start(struct device *dev, struct occ *occ,
+				  const u32 *sensor_hwmon_configs,
+				  const char *name);
+#endif /* __OCC_SYSFS_H__ */
-- 
1.8.3.1

[PATCH linux v9 3/5] hwmon: occ: Add I2C transport implementation for SCOM operations

[Eddie James]

From: "Edward A. James" <eajames@us.ibm.com>

Add functions to send SCOM operations over I2C bus. The BMC can
communicate with the Power8 host processor over I2C, but needs to use
SCOM operations in order to access the OCC register space.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 drivers/hwmon/occ/Makefile       |  2 +-
 drivers/hwmon/occ/occ_scom_i2c.c | 69 ++++++++++++++++++++++++++++++++++++++++
 drivers/hwmon/occ/occ_scom_i2c.h | 21 ++++++++++++
 3 files changed, 91 insertions(+), 1 deletion(-)
 create mode 100644 drivers/hwmon/occ/occ_scom_i2c.c
 create mode 100644 drivers/hwmon/occ/occ_scom_i2c.h

diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
index 67b5367..9cc36e7 100644
--- a/drivers/hwmon/occ/Makefile
+++ b/drivers/hwmon/occ/Makefile
@@ -1 +1 @@
-obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o occ_sysfs.o
+obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o occ_sysfs.o occ_scom_i2c.o
diff --git a/drivers/hwmon/occ/occ_scom_i2c.c b/drivers/hwmon/occ/occ_scom_i2c.c
new file mode 100644
index 0000000..351cbc5
--- /dev/null
+++ b/drivers/hwmon/occ/occ_scom_i2c.c
@@ -0,0 +1,69 @@
+/*
+ * occ_scom_i2c.c - hwmon OCC driver
+ *
+ * This file contains the functions for performing SCOM operations over I2C bus
+ * to access the OCC.
+ *
+ * Copyright 2017 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.
+ */
+
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "occ_scom_i2c.h"
+#include "scom.h"
+
+int occ_i2c_getscom(void *bus, u32 address, u64 *data)
+{
+	ssize_t rc;
+	__be64 buf;
+	struct i2c_client *client = bus;
+	struct i2c_msg msgs[2];
+
+	msgs[0].addr = client->addr;
+	msgs[0].flags = client->flags & I2C_M_TEN;
+	msgs[0].len = sizeof(u32);
+	msgs[0].buf = (char *)&address;
+
+	msgs[1].addr = client->addr;
+	msgs[1].flags = (client->flags & I2C_M_TEN) | I2C_M_RD;
+	msgs[1].len = sizeof(u64);
+	msgs[1].buf = (char *)&buf;
+
+	rc = i2c_transfer(client->adapter, msgs, 2);
+	if (rc < 0)
+		return rc;
+
+	*data = be64_to_cpu(buf);
+
+	return 0;
+}
+
+int occ_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1)
+{
+	u32 buf[3];
+	ssize_t rc;
+	struct i2c_client *client = bus;
+
+	/* send raw data, user can handle endian */
+	buf[0] = address;
+	buf[1] = data1;
+	buf[2] = data0;
+
+	rc = i2c_master_send(client, (const char *)buf, sizeof(u32) * 3);
+	if (rc < 0)
+		return rc;
+	else if (rc != sizeof(u32) * 3)
+		return -EIO;
+
+	return 0;
+}
+
+MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>");
+MODULE_DESCRIPTION("I2C OCC SCOM transport");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hwmon/occ/occ_scom_i2c.h b/drivers/hwmon/occ/occ_scom_i2c.h
new file mode 100644
index 0000000..f84647d
--- /dev/null
+++ b/drivers/hwmon/occ/occ_scom_i2c.h
@@ -0,0 +1,21 @@
+/*
+ * occ_scom_i2c.h - hwmon OCC driver
+ *
+ * This file contains function protoypes for peforming SCOM operations over I2C
+ * bus to access the OCC.
+ *
+ * Copyright 2017 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.
+ */
+
+#ifndef __OCC_SCOM_I2C_H__
+#define __OCC_SCOM_I2C_H__
+
+int occ_i2c_getscom(void *bus, u32 address, u64 *data);
+int occ_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1);
+
+#endif /* __OCC_SCOM_I2C_H__ */
-- 
1.8.3.1

[PATCH linux v9 4/5] hwmon: occ: Add callbacks for parsing P8 OCC datastructures

[Eddie James]

From: "Edward A. James" <eajames@us.ibm.com>

Add functions to parse the data structures that are specific to the OCC
on the POWER8 processor. These are the sensor data structures, including
temperature, frequency, power, and "caps."

Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 Documentation/hwmon/occ    |   9 ++
 drivers/hwmon/occ/Makefile |   2 +-
 drivers/hwmon/occ/occ_p8.c | 256 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/hwmon/occ/occ_p8.h |  25 +++++
 4 files changed, 291 insertions(+), 1 deletion(-)
 create mode 100644 drivers/hwmon/occ/occ_p8.c
 create mode 100644 drivers/hwmon/occ/occ_p8.h

diff --git a/Documentation/hwmon/occ b/Documentation/hwmon/occ
index 580af26..4ec8842 100644
--- a/Documentation/hwmon/occ
+++ b/Documentation/hwmon/occ
@@ -27,6 +27,15 @@ 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.
 
+The format for the POWER8 OCC sensor data can be found in the P8 OCC
+specification:
+github.com/open-power/docs/blob/master/occ/OCC_OpenPwr_FW_Interfaces.pdf
+This document provides the details of the OCC sensors: power, frequency,
+temperature, and caps. These sensor formats are specific to the POWER8 OCC. A
+number of data structures, such as command format, response headers, and the
+like, are also defined in this specification, and are common to both POWER8 and
+POWER9 OCCs.
+
 sysfs Entries
 -------------
 
diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
index 9cc36e7..f59cca4 100644
--- a/drivers/hwmon/occ/Makefile
+++ b/drivers/hwmon/occ/Makefile
@@ -1 +1 @@
-obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o occ_sysfs.o occ_scom_i2c.o
+obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o occ_sysfs.o occ_scom_i2c.o occ_p8.o
diff --git a/drivers/hwmon/occ/occ_p8.c b/drivers/hwmon/occ/occ_p8.c
new file mode 100644
index 0000000..ae8b453
--- /dev/null
+++ b/drivers/hwmon/occ/occ_p8.c
@@ -0,0 +1,256 @@
+/*
+ * occ_p8.c - OCC hwmon driver
+ *
+ * This file contains the Power8-specific methods and data structures for
+ * the OCC hwmon driver.
+ *
+ * Copyright 2017 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.
+ */
+
+#include <asm/unaligned.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include "occ.h"
+#include "occ_p8.h"
+
+/* P8 OCC sensor data format */
+struct p8_occ_sensor {
+	u16 sensor_id;
+	u16 value;
+};
+
+struct p8_power_sensor {
+	u16 sensor_id;
+	u32 update_tag;
+	u32 accumulator;
+	u16 value;
+};
+
+struct p8_caps_sensor {
+	u16 curr_powercap;
+	u16 curr_powerreading;
+	u16 norm_powercap;
+	u16 max_powercap;
+	u16 min_powercap;
+	u16 user_powerlimit;
+};
+
+/* value, sensor_id */
+#define FREQ_SENSOR_CONFIG	(HWMON_I_INPUT | HWMON_I_LABEL)
+#define TEMP_SENSOR_CONFIG	(HWMON_T_INPUT | HWMON_T_LABEL)
+
+/* value, sensor_id, accumulator, update_tag */
+#define POWER_SENSOR_CONFIG					\
+(								\
+	HWMON_P_INPUT | HWMON_P_LABEL | HWMON_P_AVERAGE |	\
+	HWMON_P_AVERAGE_INTERVAL				\
+)
+
+/* curr_powercap, max_powercap, min_powercap, norm_powercap, user_powerlimit */
+#define CAPS_SENSOR_CONFIG						\
+(									\
+	HWMON_P_CAP | HWMON_P_CAP_MAX | HWMON_P_CAP_MIN | HWMON_P_MAX |	\
+	HWMON_P_ALARM							\
+)
+
+static const u32 p8_sensor_hwmon_configs[MAX_OCC_SENSOR_TYPE] = {
+	FREQ_SENSOR_CONFIG,
+	TEMP_SENSOR_CONFIG,
+	POWER_SENSOR_CONFIG,
+	CAPS_SENSOR_CONFIG,
+};
+
+void p8_parse_sensor(u8 *data, void *sensor, int sensor_type, int off,
+		     int snum)
+{
+	switch (sensor_type) {
+	case FREQ:
+	case TEMP:
+	{
+		struct p8_occ_sensor *os =
+			&(((struct p8_occ_sensor *)sensor)[snum]);
+
+		os->sensor_id = be16_to_cpu(get_unaligned((u16 *)&data[off]));
+		os->value = be16_to_cpu(get_unaligned((u16 *)&data[off + 2]));
+	}
+		break;
+	case POWER:
+	{
+		struct p8_power_sensor *ps =
+			&(((struct p8_power_sensor *)sensor)[snum]);
+
+		ps->sensor_id = be16_to_cpu(get_unaligned((u16 *)&data[off]));
+		ps->update_tag =
+			be32_to_cpu(get_unaligned((u32 *)&data[off + 2]));
+		ps->accumulator =
+			be32_to_cpu(get_unaligned((u32 *)&data[off + 6]));
+		ps->value = be16_to_cpu(get_unaligned((u16 *)&data[off + 10]));
+	}
+		break;
+	case CAPS:
+	{
+		struct p8_caps_sensor *cs =
+			&(((struct p8_caps_sensor *)sensor)[snum]);
+
+		cs->curr_powercap =
+			be16_to_cpu(get_unaligned((u16 *)&data[off]));
+		cs->curr_powerreading =
+			be16_to_cpu(get_unaligned((u16 *)&data[off + 2]));
+		cs->norm_powercap =
+			be16_to_cpu(get_unaligned((u16 *)&data[off + 4]));
+		cs->max_powercap =
+			be16_to_cpu(get_unaligned((u16 *)&data[off + 6]));
+		cs->min_powercap =
+			be16_to_cpu(get_unaligned((u16 *)&data[off + 8]));
+		cs->user_powerlimit =
+			be16_to_cpu(get_unaligned((u16 *)&data[off + 10]));
+	}
+		break;
+	};
+}
+
+void *p8_alloc_sensor(struct device *dev, int sensor_type, int num_sensors)
+{
+	switch (sensor_type) {
+	case FREQ:
+	case TEMP:
+		return devm_kzalloc(dev, num_sensors *
+				    sizeof(struct p8_occ_sensor), GFP_KERNEL);
+	case POWER:
+		return devm_kzalloc(dev, num_sensors *
+				    sizeof(struct p8_power_sensor),
+				    GFP_KERNEL);
+	case CAPS:
+		return devm_kzalloc(dev, num_sensors *
+				    sizeof(struct p8_caps_sensor), GFP_KERNEL);
+	default:
+		return NULL;
+	}
+}
+
+int p8_get_sensor(struct occ *driver, int sensor_type, int sensor_num,
+		  u32 hwmon, long *val)
+{
+	int rc = 0;
+	void *sensor;
+
+	if (sensor_type == POWER) {
+		if (hwmon == hwmon_power_cap || hwmon == hwmon_power_cap_max ||
+		    hwmon == hwmon_power_cap_min || hwmon == hwmon_power_max ||
+		    hwmon == hwmon_power_alarm)
+			sensor_type = CAPS;
+	}
+
+	sensor = occ_get_sensor(driver, sensor_type);
+	if (!sensor)
+		return -ENODEV;
+
+	switch (sensor_type) {
+	case FREQ:
+	case TEMP:
+	{
+		struct p8_occ_sensor *os =
+			&(((struct p8_occ_sensor *)sensor)[sensor_num]);
+
+		if (hwmon == hwmon_in_input || hwmon == hwmon_temp_input)
+			*val = os->value;
+		else if (hwmon == hwmon_in_label || hwmon == hwmon_temp_label)
+			*val = os->sensor_id;
+		else
+			rc = -EOPNOTSUPP;
+	}
+		break;
+	case POWER:
+	{
+		struct p8_power_sensor *ps =
+			&(((struct p8_power_sensor *)sensor)[sensor_num]);
+
+		switch (hwmon) {
+		case hwmon_power_input:
+			*val = ps->value;
+			break;
+		case hwmon_power_label:
+			*val = ps->sensor_id;
+			break;
+		case hwmon_power_average:
+			*val = ps->accumulator;
+			break;
+		case hwmon_power_average_interval:
+			*val = ps->update_tag;
+			break;
+		default:
+			rc = -EOPNOTSUPP;
+		}
+	}
+		break;
+	case CAPS:
+	{
+		struct p8_caps_sensor *cs =
+			&(((struct p8_caps_sensor *)sensor)[sensor_num]);
+
+		switch (hwmon) {
+		case hwmon_power_cap:
+			*val = cs->curr_powercap;
+			break;
+		case hwmon_power_cap_max:
+			*val = cs->max_powercap;
+			break;
+		case hwmon_power_cap_min:
+			*val = cs->min_powercap;
+			break;
+		case hwmon_power_max:
+			*val = cs->norm_powercap;
+			break;
+		case hwmon_power_alarm:
+			*val = cs->user_powerlimit;
+			break;
+		default:
+			rc = -EOPNOTSUPP;
+		}
+	}
+		break;
+	default:
+		rc = -EINVAL;
+	}
+
+	return rc;
+}
+
+static const struct occ_ops p8_ops = {
+	.parse_sensor = p8_parse_sensor,
+	.alloc_sensor = p8_alloc_sensor,
+	.get_sensor = p8_get_sensor,
+};
+
+static const struct occ_init_data p8_init = {
+	.command_addr = 0xFFFF6000,
+	.response_addr = 0xFFFF7000,
+	.ops = &p8_ops,
+};
+
+const u32 *p8_get_sensor_hwmon_configs()
+{
+	return p8_sensor_hwmon_configs;
+}
+
+struct occ *p8_occ_init(struct device *dev, void *bus,
+			const struct occ_bus_ops *bus_ops)
+{
+	return occ_init(dev, bus, bus_ops, &p8_init);
+}
+
+MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>");
+MODULE_DESCRIPTION("P8 OCC sensors");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hwmon/occ/occ_p8.h b/drivers/hwmon/occ/occ_p8.h
new file mode 100644
index 0000000..5f9cceb
--- /dev/null
+++ b/drivers/hwmon/occ/occ_p8.h
@@ -0,0 +1,25 @@
+/*
+ * occ_p8.h - OCC hwmon driver
+ *
+ * This file contains Power8-specific function prototypes
+ *
+ * Copyright 2017 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.
+ */
+
+#ifndef __OCC_P8_H__
+#define __OCC_P8_H__
+
+struct device;
+struct occ;
+struct occ_bus_ops;
+
+const u32 *p8_get_sensor_hwmon_configs(void);
+struct occ *p8_occ_init(struct device *dev, void *bus,
+			const struct occ_bus_ops *bus_ops);
+
+#endif /* __OCC_P8_H__ */
-- 
1.8.3.1

[PATCH linux v9 5/5] hwmon: occ: Add hwmon implementation for the P8 OCC

[Eddie James]

From: "Edward A. James" <eajames@us.ibm.com>

Add code to tie the hwmon sysfs code and the POWER8 OCC code together,
as well as probe the entire driver from the I2C bus. I2C is the
communication method between the BMC and the P8 OCC.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/hwmon/occ.txt | 13 ++++
 drivers/hwmon/occ/Kconfig                       | 15 ++++
 drivers/hwmon/occ/Makefile                      |  4 +-
 drivers/hwmon/occ/occ_p8_i2c.c                  | 99 +++++++++++++++++++++++++
 4 files changed, 130 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/hwmon/occ.txt
 create mode 100644 drivers/hwmon/occ/occ_p8_i2c.c

diff --git a/Documentation/devicetree/bindings/hwmon/occ.txt b/Documentation/devicetree/bindings/hwmon/occ.txt
new file mode 100644
index 0000000..b0d2b36
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/occ.txt
@@ -0,0 +1,13 @@
+HWMON I2C driver for IBM POWER CPU OCC (On Chip Controller)
+
+Required properties:
+ - compatible: must be "ibm,p8-occ-i2c"
+ - reg: physical address
+
+Example:
+i2c3: i2c-bus@100 {
+	occ@50 {
+		compatible = "ibm,p8-occ-i2c";
+		reg = <0x50>;
+	};
+};
diff --git a/drivers/hwmon/occ/Kconfig b/drivers/hwmon/occ/Kconfig
index 61be588..d521720 100644
--- a/drivers/hwmon/occ/Kconfig
+++ b/drivers/hwmon/occ/Kconfig
@@ -11,3 +11,18 @@ menuconfig SENSORS_IBM_OCC
 
 	  Generally this is used by management controllers such as a BMC
 	  on an OpenPower system.
+
+if SENSORS_IBM_OCC
+
+config SENSORS_IBM_OCC_P8_I2C
+	tristate "POWER8 OCC hwmon support"
+	depends on I2C
+	help
+	  Provide a hwmon sysfs interface for the POWER8 On-Chip Controller,
+	  exposing temperature, frequency and power measurements. This
+	  interface runs on the service processor, not the POWER CPU.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called hwmon_occ_p8.
+
+endif
diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
index f59cca4..864b044 100644
--- a/drivers/hwmon/occ/Makefile
+++ b/drivers/hwmon/occ/Makefile
@@ -1 +1,3 @@
-obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o occ_sysfs.o occ_scom_i2c.o occ_p8.o
+obj-$(CONFIG_SENSORS_IBM_OCC_P8_I2C) += hwmon_occ_p8.o
+
+hwmon_occ_p8-objs := occ.o occ_sysfs.o occ_scom_i2c.o occ_p8.o occ_p8_i2c.o
diff --git a/drivers/hwmon/occ/occ_p8_i2c.c b/drivers/hwmon/occ/occ_p8_i2c.c
new file mode 100644
index 0000000..2b4f6dd
--- /dev/null
+++ b/drivers/hwmon/occ/occ_p8_i2c.c
@@ -0,0 +1,99 @@
+/*
+ * occ_p8_i2c.c - hwmon OCC driver
+ *
+ * This file contains the i2c layer for accessing the P8 OCC over i2c bus.
+ *
+ * Copyright 2017 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.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include "occ_p8.h"
+#include "occ_scom_i2c.h"
+#include "occ_sysfs.h"
+#include "scom.h"
+
+#define OCC_P8_I2C_NAME	"p8-occ-i2c"
+
+int p8_i2c_getscom(void *bus, u32 address, u64 *data)
+{
+	/* P8 i2c slave requires scom address to be shifted by 1 */
+	address = address << 1;
+
+	return occ_i2c_getscom(bus, address, data);
+}
+
+int p8_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1)
+{
+	/* P8 i2c slave requires scom address to be shifted by 1 */
+	address = address << 1;
+
+	return occ_i2c_putscom(bus, address, data0, data1);
+}
+
+static const struct occ_bus_ops p8_bus_ops = {
+	.getscom = p8_i2c_getscom,
+	.putscom = p8_i2c_putscom,
+};
+
+static int p8_occ_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct occ *occ;
+	struct occ_sysfs *hwmon;
+	const u32 *sensor_hwmon_configs = p8_get_sensor_hwmon_configs();
+
+	occ = p8_occ_init(&client->dev, client, &p8_bus_ops);
+	if (IS_ERR(occ))
+		return PTR_ERR(occ);
+
+	hwmon = occ_sysfs_start(&client->dev, occ, sensor_hwmon_configs,
+				OCC_P8_I2C_NAME);
+	if (IS_ERR(hwmon))
+		return PTR_ERR(hwmon);
+
+	i2c_set_clientdata(client, occ);
+
+	return 0;
+}
+
+/* used by old-style board info. */
+static const struct i2c_device_id occ_ids[] = {
+	{ OCC_P8_I2C_NAME, 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, occ_ids);
+
+/* used by device table */
+static const struct of_device_id occ_of_match[] = {
+	{ .compatible = "ibm,p8-occ-i2c" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, occ_of_match);
+
+static struct i2c_driver p8_occ_driver = {
+	.class = I2C_CLASS_HWMON,
+	.driver = {
+		.name = OCC_P8_I2C_NAME,
+		.of_match_table = occ_of_match,
+	},
+	.probe = p8_occ_probe,
+	.id_table = occ_ids,
+};
+
+module_i2c_driver(p8_occ_driver);
+
+MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>");
+MODULE_DESCRIPTION("BMC P8 OCC hwmon driver");
+MODULE_LICENSE("GPL");
-- 
1.8.3.1

Re: [PATCH linux v9 2/5] hwmon: occ: Add sysfs interface

[Guenter Roeck]

On 03/14/2017 01:55 PM, Eddie James wrote:
> From: "Edward A. James" <eajames@us.ibm.com>
>
> Add a generic mechanism to expose the sensors provided by the OCC in
> sysfs.
>
> Signed-off-by: Edward A. James <eajames@us.ibm.com>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> ---
>  Documentation/hwmon/occ       |  62 +++++++++++
>  drivers/hwmon/occ/Makefile    |   2 +-
>  drivers/hwmon/occ/occ_sysfs.c | 253 ++++++++++++++++++++++++++++++++++++++++++
>  drivers/hwmon/occ/occ_sysfs.h |  25 +++++
>  4 files changed, 341 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/hwmon/occ/occ_sysfs.c
>  create mode 100644 drivers/hwmon/occ/occ_sysfs.h
>
> diff --git a/Documentation/hwmon/occ b/Documentation/hwmon/occ
> index d1c863b..580af26 100644
> --- a/Documentation/hwmon/occ
> +++ b/Documentation/hwmon/occ
> @@ -27,6 +27,68 @@ 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.
>
> +sysfs Entries
> +-------------
> +
> +The OCC driver uses the hwmon sysfs framework to provide data to userspace.
> +
> +The driver exports a number of sysfs files for each type of sensor. The
> +sensor-specific files vary depending on the processor type, though many of the
> +attributes are common for both the POWER8 and POWER9.
> +
> +The hwmon interface cannot define every type of sensor that may be used.
> +Therefore, the frequency sensor on the OCC uses the "input" type sensor defined
> +by the hwmon interface, rather than defining a new type of custom sensor.
> +
> +Below are detailed the names and meaning of each sensor file for both types of
> +processors. All sensors are read-only unless otherwise specified. <x> indicates
> +the hwmon index. sensor id indicates the unique internal OCC identifer. Please
> +see the POWER OCC specification for details on all these sensor values.
> +
> +frequency:
> +	all processors:
> +		in<x>_input - frequency value
> +		in<x>_label - sensor id
> +temperature:
> +	POWER8:
> +		temp<x>_input - temperature value
> +		temp<x>_label - sensor id
> +	POWER9 (in addition to above):
> +		temp<x>_type - FRU type
> +
> +power:
> +	POWER8:
> +		power<x>_input - power value
> +		power<x>_label - sensor id
> +		power<x>_average - accumulator
> +		power<x>_average_interval - update tag (number of samples in
> +			accumulator)
> +	POWER9:
> +		power<x>_input - power value
> +		power<x>_label - sensor id
> +		power<x>_average_min - accumulator[0]
> +		power<x>_average_max - accumulator[1] (64 bits total)
> +		power<x>_average_interval - update tag
> +		power<x>_reset_history - (function_id | (apss_channel << 8)
> +
> +caps:
> +	POWER8:
> +		power<x>_cap - current powercap
> +		power<x>_cap_max - max powercap
> +		power<x>_cap_min - min powercap
> +		power<x>_max - normal powercap
> +		power<x>_alarm - user powercap, r/w
> +	POWER9:
> +		power<x>_cap_alarm - user powercap source
> +
> +The driver also provides two sysfs entries through hwmon to better
> +control the driver and monitor the master OCC. Though there may be multiple
> +OCCs present on the system, these two files are only present for the "master"
> +OCC.
> +	name - read the name of the driver
> +	update_interval - read or write the minimum interval for polling the
> +		OCC.
> +
>  BMC - Host Communications
>  -------------------------
>
> diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
> index 3ed79a5..67b5367 100644
> --- a/drivers/hwmon/occ/Makefile
> +++ b/drivers/hwmon/occ/Makefile
> @@ -1 +1 @@
> -obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o
> +obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o occ_sysfs.o
> diff --git a/drivers/hwmon/occ/occ_sysfs.c b/drivers/hwmon/occ/occ_sysfs.c
> new file mode 100644
> index 0000000..50b20e2
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ_sysfs.c
> @@ -0,0 +1,253 @@
> +/*
> + * occ_sysfs.c - OCC sysfs interface
> + *
> + * This file contains the methods and data structures for implementing the OCC
> + * hwmon sysfs entries.
> + *
> + * Copyright 2017 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.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.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"
> +#include "occ_sysfs.h"
> +
> +#define OCC_HWMON_NAME_LENGTH	32
> +
> +struct occ_sysfs {
> +	struct device *dev;
> +	struct occ *occ;
> +
> +	char label_buffer[OCC_HWMON_NAME_LENGTH + 1];
> +	char hwmon_name[OCC_HWMON_NAME_LENGTH + 1];
> +	const u32 *sensor_hwmon_configs;
> +	struct hwmon_channel_info **occ_sensors;
> +	struct hwmon_chip_info occ_info;
> +	u16 user_powercap;
> +};
> +
> +static int occ_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
> +			  u32 attr, int channel, long *val)
> +{
> +	int rc;
> +	struct occ_sysfs *driver = dev_get_drvdata(dev);
> +	struct occ *occ = driver->occ;
> +
> +	switch (type) {
> +	case hwmon_in:
> +		rc = occ_get_sensor_field(occ, FREQ, channel, attr, val);
> +		break;
> +	case hwmon_temp:
> +		rc = occ_get_sensor_field(occ, TEMP, channel, attr, val);
> +		break;
> +	case hwmon_power:
> +		rc = occ_get_sensor_field(occ, POWER, channel, attr, val);
> +		break;
> +	default:
> +		rc = -EOPNOTSUPP;
> +	}
> +
> +	return rc;
> +}
> +
> +static int occ_hwmon_read_string(struct device *dev,
> +				 enum hwmon_sensor_types type, u32 attr,
> +				 int channel, const char **str)
> +{
> +	int rc;
> +	unsigned long val = 0;
> +	struct occ_sysfs *driver = dev_get_drvdata(dev);
> +
> +	if (!((type == hwmon_in && attr == hwmon_in_label) ||
> +	    (type == hwmon_temp && attr == hwmon_temp_label) ||
> +	    (type == hwmon_power && attr == hwmon_power_label)))
> +		return -EOPNOTSUPP;
> +
> +	/* will fetch the "label", the sensor_id */
> +	rc = occ_hwmon_read(dev, type, attr, channel, &val);
> +	if (rc < 0)
> +		return rc;
> +
> +	/* just use one label buffer for all sensors. works with current hwmon
> +	 * implementation. only alternative is to store a buffer for each
> +	 * sensor, which gets expensive quickly.
> +	 */

Sorry for the late reply.

No, this doesn't work and is racy. Reading all labels from multiple threads
in parallel will result in random data.

The label is supposed to be constant for each sensor. If it isn't, it is not
a label. Either create it as constant and use the generated string, or drop
the attribute.

Guenter

Re: [PATCH linux v9 2/5] hwmon: occ: Add sysfs interface

[Eddie James]

On 04/02/2017 06:19 AM, Guenter Roeck wrote:
> On 03/14/2017 01:55 PM, Eddie James wrote:
>> From: "Edward A. James" <eajames@us.ibm.com>
>>
>> Add a generic mechanism to expose the sensors provided by the OCC in
>> sysfs.
>>
>> Signed-off-by: Edward A. James <eajames@us.ibm.com>
>> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
>> ---
>>  Documentation/hwmon/occ       |  62 +++++++++++
>>  drivers/hwmon/occ/Makefile    |   2 +-
>>  drivers/hwmon/occ/occ_sysfs.c | 253 
>> ++++++++++++++++++++++++++++++++++++++++++
>>  drivers/hwmon/occ/occ_sysfs.h |  25 +++++
>>  4 files changed, 341 insertions(+), 1 deletion(-)
>>  create mode 100644 drivers/hwmon/occ/occ_sysfs.c
>>  create mode 100644 drivers/hwmon/occ/occ_sysfs.h
>>
>> diff --git a/Documentation/hwmon/occ b/Documentation/hwmon/occ
>> index d1c863b..580af26 100644
>> --- a/Documentation/hwmon/occ
>> +++ b/Documentation/hwmon/occ
>> @@ -27,6 +27,68 @@ 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.
>>
>> +sysfs Entries
>> +-------------
>> +
>> +The OCC driver uses the hwmon sysfs framework to provide data to 
>> userspace.
>> +
>> +The driver exports a number of sysfs files for each type of sensor. The
>> +sensor-specific files vary depending on the processor type, though 
>> many of the
>> +attributes are common for both the POWER8 and POWER9.
>> +
>> +The hwmon interface cannot define every type of sensor that may be 
>> used.
>> +Therefore, the frequency sensor on the OCC uses the "input" type 
>> sensor defined
>> +by the hwmon interface, rather than defining a new type of custom 
>> sensor.
>> +
>> +Below are detailed the names and meaning of each sensor file for 
>> both types of
>> +processors. All sensors are read-only unless otherwise specified. 
>> <x> indicates
>> +the hwmon index. sensor id indicates the unique internal OCC 
>> identifer. Please
>> +see the POWER OCC specification for details on all these sensor values.
>> +
>> +frequency:
>> +    all processors:
>> +        in<x>_input - frequency value
>> +        in<x>_label - sensor id
>> +temperature:
>> +    POWER8:
>> +        temp<x>_input - temperature value
>> +        temp<x>_label - sensor id
>> +    POWER9 (in addition to above):
>> +        temp<x>_type - FRU type
>> +
>> +power:
>> +    POWER8:
>> +        power<x>_input - power value
>> +        power<x>_label - sensor id
>> +        power<x>_average - accumulator
>> +        power<x>_average_interval - update tag (number of samples in
>> +            accumulator)
>> +    POWER9:
>> +        power<x>_input - power value
>> +        power<x>_label - sensor id
>> +        power<x>_average_min - accumulator[0]
>> +        power<x>_average_max - accumulator[1] (64 bits total)
>> +        power<x>_average_interval - update tag
>> +        power<x>_reset_history - (function_id | (apss_channel << 8)
>> +
>> +caps:
>> +    POWER8:
>> +        power<x>_cap - current powercap
>> +        power<x>_cap_max - max powercap
>> +        power<x>_cap_min - min powercap
>> +        power<x>_max - normal powercap
>> +        power<x>_alarm - user powercap, r/w
>> +    POWER9:
>> +        power<x>_cap_alarm - user powercap source
>> +
>> +The driver also provides two sysfs entries through hwmon to better
>> +control the driver and monitor the master OCC. Though there may be 
>> multiple
>> +OCCs present on the system, these two files are only present for the 
>> "master"
>> +OCC.
>> +    name - read the name of the driver
>> +    update_interval - read or write the minimum interval for polling 
>> the
>> +        OCC.
>> +
>>  BMC - Host Communications
>>  -------------------------
>>
>> diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
>> index 3ed79a5..67b5367 100644
>> --- a/drivers/hwmon/occ/Makefile
>> +++ b/drivers/hwmon/occ/Makefile
>> @@ -1 +1 @@
>> -obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o
>> +obj-$(CONFIG_SENSORS_IBM_OCC) += occ.o occ_sysfs.o
>> diff --git a/drivers/hwmon/occ/occ_sysfs.c 
>> b/drivers/hwmon/occ/occ_sysfs.c
>> new file mode 100644
>> index 0000000..50b20e2
>> --- /dev/null
>> +++ b/drivers/hwmon/occ/occ_sysfs.c
>> @@ -0,0 +1,253 @@
>> +/*
>> + * occ_sysfs.c - OCC sysfs interface
>> + *
>> + * This file contains the methods and data structures for 
>> implementing the OCC
>> + * hwmon sysfs entries.
>> + *
>> + * Copyright 2017 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.
>> + */
>> +
>> +#include <linux/delay.h>
>> +#include <linux/device.h>
>> +#include <linux/err.h>
>> +#include <linux/hwmon.h>
>> +#include <linux/hwmon-sysfs.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"
>> +#include "occ_sysfs.h"
>> +
>> +#define OCC_HWMON_NAME_LENGTH    32
>> +
>> +struct occ_sysfs {
>> +    struct device *dev;
>> +    struct occ *occ;
>> +
>> +    char label_buffer[OCC_HWMON_NAME_LENGTH + 1];
>> +    char hwmon_name[OCC_HWMON_NAME_LENGTH + 1];
>> +    const u32 *sensor_hwmon_configs;
>> +    struct hwmon_channel_info **occ_sensors;
>> +    struct hwmon_chip_info occ_info;
>> +    u16 user_powercap;
>> +};
>> +
>> +static int occ_hwmon_read(struct device *dev, enum 
>> hwmon_sensor_types type,
>> +              u32 attr, int channel, long *val)
>> +{
>> +    int rc;
>> +    struct occ_sysfs *driver = dev_get_drvdata(dev);
>> +    struct occ *occ = driver->occ;
>> +
>> +    switch (type) {
>> +    case hwmon_in:
>> +        rc = occ_get_sensor_field(occ, FREQ, channel, attr, val);
>> +        break;
>> +    case hwmon_temp:
>> +        rc = occ_get_sensor_field(occ, TEMP, channel, attr, val);
>> +        break;
>> +    case hwmon_power:
>> +        rc = occ_get_sensor_field(occ, POWER, channel, attr, val);
>> +        break;
>> +    default:
>> +        rc = -EOPNOTSUPP;
>> +    }
>> +
>> +    return rc;
>> +}
>> +
>> +static int occ_hwmon_read_string(struct device *dev,
>> +                 enum hwmon_sensor_types type, u32 attr,
>> +                 int channel, const char **str)
>> +{
>> +    int rc;
>> +    unsigned long val = 0;
>> +    struct occ_sysfs *driver = dev_get_drvdata(dev);
>> +
>> +    if (!((type == hwmon_in && attr == hwmon_in_label) ||
>> +        (type == hwmon_temp && attr == hwmon_temp_label) ||
>> +        (type == hwmon_power && attr == hwmon_power_label)))
>> +        return -EOPNOTSUPP;
>> +
>> +    /* will fetch the "label", the sensor_id */
>> +    rc = occ_hwmon_read(dev, type, attr, channel, &val);
>> +    if (rc < 0)
>> +        return rc;
>> +
>> +    /* just use one label buffer for all sensors. works with current 
>> hwmon
>> +     * implementation. only alternative is to store a buffer for each
>> +     * sensor, which gets expensive quickly.
>> +     */
>
> Sorry for the late reply.
>
> No, this doesn't work and is racy. Reading all labels from multiple 
> threads
> in parallel will result in random data.
>
> The label is supposed to be constant for each sensor. If it isn't, it 
> is not
> a label. Either create it as constant and use the generated string, or 
> drop
> the attribute.
>
> Guenter

Thanks for catching that. The driver is undergoing some significant 
restructuring as a result of changes in design to the low-level driver 
for the P9 side of things (actually doing the communication with the 
OCC). Depending on how extensive the changes are (haven't had time to 
finalize), this patchset could be abandoned and I'll start again.

Thanks for the feedback so far.

Eddie