Guenter Roeck <linux@roeck-us.net> wrote on 01/23/2017 04:15:40 PM:
> On Mon, Jan 23, 2017 at 04:01:25PM -0600, Edward James wrote:
> >
> >
> > On Sat, Jan 21, 2017 at 12:08 PM, Guenter Roeck <linux@roeck-us.net> wrote:
> > > On 01/16/2017 01:13 PM, eajames.ibm@gmail.com 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 | 271
> > >> ++++++++++++++++++++++++++++++++++++++++++
> > >> drivers/hwmon/occ/occ_sysfs.h | 44 +++++++
> > >> 4 files changed, 378 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..2f20c40
> > >> --- /dev/null
> > >> +++ b/drivers/hwmon/occ/occ_sysfs.c
> > >> @@ -0,0 +1,271 @@
> > >> +/*
> > >> + * 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 RESP_RETURN_CMD_INVAL 0x13
> > >> +
> > >> +static int occ_hwmon_read(struct device *dev, enum hwmon_sensor_types
> > >> type,
> > >> + u32 attr, int channel, long *val)
> > >> +{
> > >> + int rc = 0;
> > >
> > >
> > > Unnecessary initialization.
> >
> > Got it.
> >
> > >
> > >
> > >> + struct occ_sysfs *driver = dev_get_drvdata(dev);
> > >> + struct occ *occ = driver->occ;
> > >> +
> > >> + switch (type) {
> > >> + case hwmon_in:
> > >> + rc = occ_get_sensor_value(occ, FREQ, channel, attr,
> > val);
> > >> + break;
> > >> + case hwmon_temp:
> > >> + rc = occ_get_sensor_value(occ, TEMP, channel, attr,
> > val);
> > >> + break;
> > >> + case hwmon_power:
> > >> + rc = occ_get_sensor_value(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;
> > >> +
> > >> + rc = occ_hwmon_read(dev, type, attr, channel, &val);
> > >> + if (rc < 0)
> > >> + return rc;
> > >> +
> > >> + rc = snprintf(*str, PAGE_SIZE - 1, "%ld", val);
> > >
> > >
> > > val is unsigned long.
> > >
> > > I am quite confused what this is for, though. The function is used for
> > > string attributes,
> > > or in other words for labels. What is the benefit of having a label that
> > > returns the same
> > > data as the value attribute ? Is this maybe a misunderstanding ?
> >
> > So this does work, though I admit it's a bit confusing.
> > occ_get_sensor_value returns either the value or the occ sensor id
> > depending on the "type" passed in. I'll rename occ_get_sensor_value
> > and add a comment.
> >
> > >
> > >> + 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 = 0;
> > >> + struct occ_sysfs *driver = dev_get_drvdata(dev);
> > >> +
> > >> + if (type == hwmon_chip && attr == hwmon_chip_update_interval) {
> > >> + occ_set_update_interval(driver->occ, val);
> > >
> > >
> > > As mentioned in the other patch, please drop. This is not the intended
> > use
> > > case
> > > for this attribute.
> >
> > OK.
> >
> > >
> > >
> > >> + return 0;
> > >> + } else if (type == hwmon_power && attr == hwmon_power_alarm) {
> > >> + rc = occ_set_user_powercap(driver->occ, val);
> > >> + if (rc) {
> > >> + if (rc == RESP_RETURN_CMD_INVAL) {
> > >> + dev_err(dev,
> > >> + "set invalid powercap value:
> > >> %ld\n",
> > >> + val);
> > >> + return -EINVAL;
> > >> + }
> > >> +
> > >> + dev_err(dev, "set user powercap failed: 0x:%x
> > \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 S_IRUGO | S_IWUSR;
> > >> + break;
> > >> + case hwmon_in:
> > >> + if (BIT(attr) & driver->sensor_hwmon_configs[0])
> > >> + return S_IRUGO;
> > >> + break;
> > >> + case hwmon_temp:
> > >> + if (BIT(attr) & driver->sensor_hwmon_configs[1])
> > >> + return S_IRUGO;
> > >> + break;
> > >> + case hwmon_power:
> > >> + /* user power limit */
> > >> + if (attr == hwmon_power_alarm)
> > >> + return S_IRUGO | S_IWUSR;
> > >> + else if ((BIT(attr) & driver->sensor_hwmon_configs[2])
> > ||
> > >> + (BIT(attr) & driver->sensor_hwmon_configs[3]))
> > >> + return S_IRUGO;
> > >> + break;
> > >> + default:
> > >> + return 0;
> > >
> > >
> > > Might as well use break; here for consistency.
> > >
> > >
> > >> + }
> > >> +
> > >> + 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 u32 occ_chip_config[] = {
> > >> + HWMON_C_UPDATE_INTERVAL,
> > >> + 0
> > >> +};
> > >> +
> > >> +static const struct hwmon_channel_info occ_chip = {
> > >> + .type = hwmon_chip,
> > >> + .config = occ_chip_config
> > >> +};
> > >> +
> > >> +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)
> > >> +{
> > >> + bool master_occ = false;
> > >> + int rc, i, j, sensor_num, 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 and occ chip */
> > >> + hwmon->occ_sensors =
> > >> + devm_kzalloc(dev, sizeof(struct hwmon_channel_info *) *
> > >> + (MAX_OCC_SENSOR_TYPE + 2), GFP_KERNEL);
> > >> + if (!hwmon->occ_sensors)
> > >> + return ERR_PTR(-ENOMEM);
> > >> +
> > >> + hwmon->occ = occ;
> > >> + hwmon->sensor_hwmon_configs = (u32 *)sensor_hwmon_configs;
> > >
> > >
> > > Either this is a const or it isn't. If it isn't, it should not be passed
> > in
> > > as const.
> > > If it is, it can be declared const in struct occ_sysfs.
> >
> > It is const, i'll fix.
> >
> > >
> > >
> > >> + hwmon->occ_info.ops = &occ_hwmon_ops;
> > >> + hwmon->occ_info.info =
> > >> + (const struct hwmon_channel_info **)hwmon->occ_sensors;
> > >
> > >
> > > Why is this typecast needed ?
> >
> > struct hwmon_chip_info {
> > const struct hwmon_ops *ops;
> > const struct hwmon_channel_info **info;
> > };
> >
> > My compiler throws an error without a cast here.
> >
> > occ_sysfs.c:195:23: error: assignment from incompatible pointer type
> > [-Werror=incompatible-pointer-types]
> > | hwmon->occ_info.info = hwmon->occ_sensors;
> >
> > occ_sensors is not const, as it's dynamically zero-allocated and then
> > if we poll and get a sensor, we allocate a new hwmon_channel_info. Not
> > sure what the best solution is here except to cast.
> >
>
> Your statement makes me quite concerned. "if we poll and get a sensor, we
> allocate a new hwmon_channel_info". Are you doing that before or after
> registering with the hwmon core ? Hopefully before.
All before registration. There is no changing of hwmon attributes after we
probe the driver. But we need the first poll response to allocate the
hwmon_channel_info structures and others to match the sensors found in the
first poll response.
>
> > >
> > >
> > >> +
> > >> + 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) {
> > >> + dev_err(dev, "cannot get occ sensor data: %d\n", rc);
> > >> + return ERR_PTR(rc);
> > >> + }
> > >> + if (!resp->blocks)
> > >> + return ERR_PTR(-ENOMEM);
> > >> +
> > >> + master_occ = resp->sensor_block_id[CAPS] >= 0;
> > >> +
> > >> + for (i = 0; i < MAX_OCC_SENSOR_TYPE; i++) {
> > >> + id = resp->sensor_block_id[i];
> > >> + if (id < 0)
> > >> + continue;
> > >> +
> > >> + sensor_num = resp->blocks[id].header.sensor_num;
> > >> + /* need null-termination */
> > >> + sensor_config = devm_kzalloc(dev,
> > >> + sizeof(u32) * (sensor_num +
> > >> 1),
> > >> + GFP_KERNEL);
> > >> + if (!sensor_config)
> > >> + return ERR_PTR(-ENOMEM);
> > >> +
> > >> + for (j = 0; j < sensor_num; 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++;
> > >> + }
> > >
> > >
> > > I had the impression from patch 1 that the number of sensors can change
> > at
> > > runtime.
> > > If so, this doesn't really work well; the sysfs attributes won't be
> > updated
> > > in this
> > > case.
> > >
> > > Can it really happen that the sensor information can change ?
> >
> > Well, the number of sensors won't change while we are running. But we
> > don't know how many sensors we have when we start up. So this first
> > poll will tell us how many we need and allow the driver to initialize
> > the correct number of hwmon attributes. But yes, it shouldn't change while
> > we
> > are running.
> >
> I'll have to look into the other patch again. I seem to recall that it does
> handle changing number of sensors, but I may be wrong.
Yes, the core driver does handle varying sensors. But this was designed mainly
just to handle the first poll response. The core doesn't know which poll
response is the first, so it made sense to just handle any number of sensors
each time we poll.
Also, the OCC specification doesn't indicate that the poll
response *must* have the same number of sensors each time it's polled... so
perhaps it may change in some conditions. But the hwmon attributes won't change.
That's OK for us.
>
> > >
> > >> +
> > >> + /* only need one of these for any number of occs */
> > >> + if (master_occ)
> > >> + hwmon->occ_sensors[index] =
> > >> + (struct hwmon_channel_info *)&occ_chip;
> > >
> > >
> > > Why this typecast ?
> >
> > occ_chip is const but my occ_sensors field isn't.
> >
> Hmm .. I'll have to have a closer look. Maybe I need to make the core fields
> non-const. Having to use typecasts isn't really desirable and defeats the
> purpose.
OK, agreed, thanks.
Eddie
>
> Guenter
>
> > >
> > >
> > >> +
> > >> + /* 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..7de92e7
> > >> --- /dev/null
> > >> +++ b/drivers/hwmon/occ/occ_sysfs.h
> > >> @@ -0,0 +1,44 @@
> > >> +/*
> > >> + * 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__
> > >> +
> > >> +#include <linux/hwmon.h>
> > >> +
> > >> +struct occ;
> > >> +struct device;
> > >> +
> > >> +#define OCC_HWMON_NAME_LENGTH 32
> > >> +
> > >> +struct occ_sysfs {
> > >> + struct device *dev;
> > >> + struct occ *occ;
> > >> +
> > >> + char hwmon_name[OCC_HWMON_NAME_LENGTH + 1];
> > >> + u32 *sensor_hwmon_configs;
> > >> + struct hwmon_channel_info **occ_sensors;
> > >> + struct hwmon_chip_info occ_info;
> > >> + u16 user_powercap;
> > >> +};
> > >
> > >
> > > Is this information used outside the sysfs code ? If not, it should be
> > > defined
> > > in the source file and not be available outside of it.
> >
> > OK. It is used in p8_occ_i2c.c but none of the members are accessed so
> > we shouldn't need it defined there, just declared, you're right.
> >
> >
> > >
> > >
> > >> +
> > >> +struct occ_sysfs *occ_sysfs_start(struct device *dev, struct occ *occ,
> > >> + const u32 *sensor_hwmon_configs,
> > >> + const char *name);
> > >> +#endif /* __OCC_SYSFS_H__ */
> > >>
> > >
>