[PATCH linux v5 2/6] hwmon: occ: Add sysfs interface

eajames.ibm
2017-01-31T00:13:19Z

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 | 251 ++++++++++++++++++++++++++++++++++++++++++
drivers/hwmon/occ/occ_sysfs.h | 30 +++++
4 files changed, 344 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 79d1642..d0bdf06 100644
--- a/Documentation/hwmon/occ
+++ b/Documentation/hwmon/occ
@@ -25,6 +25,68 @@ 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 93cb52f..a6881f9 100644
--- a/drivers/hwmon/occ/Makefile
+++ b/drivers/hwmon/occ/Makefile
@@ -1 +1 @@
-obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o
+obj-$(CONFIG_SENSORS_PPC_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..9598f78
--- /dev/null
+++ b/drivers/hwmon/occ/occ_sysfs.c
@@ -0,0 +1,251 @@
+/*
+ * occ_sysfs.c - OCC sysfs interface
+ *
+ * This file contains the methods and data structures for implementing the OCC
+ * hwmon sysfs entries.
+ *
+ * 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 <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 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, char **str)
+{
+ int rc;
+ unsigned long val = 0;
+
+ 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;
+
+ rc = snprintf(*str, PAGE_SIZE - 1, "%lu", val);
+ if (rc > 0)
+ rc = 0;
+
+ 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 00644;
+ break;
+ case hwmon_in:
+ if (BIT(attr) & driver->sensor_hwmon_configs[0])
+ return 00444;
+ break;
+ case hwmon_temp:
+ if (BIT(attr) & driver->sensor_hwmon_configs[1])
+ return 00444;
+ break;
+ case hwmon_power:
+ /* user power limit */
+ if (attr == hwmon_power_alarm)
+ return 00644;
+ else if ((BIT(attr) & driver->sensor_hwmon_configs[2]) ||
+ (BIT(attr) & driver->sensor_hwmon_configs[3]))
+ return 00444;
+ 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;
+}
+EXPORT_SYMBOL(occ_sysfs_start);
+
+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..462f9d2
--- /dev/null
+++ b/drivers/hwmon/occ/occ_sysfs.h
@@ -0,0 +1,30 @@
+/*
+ * occ_sysfs.h - OCC sysfs interface
+ *
+ * This file contains the data structures and function prototypes for the OCC
+ * hwmon sysfs entries.
+ *
+ * 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_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