hwmon: (occ) Check for device property for setting OCC active during probe

A previous commit changed the existing behavior of the driver to skip
attempting to communicate with the OCC during probe. Return to the
previous default behavior of automatically communicating with the OCC
and make it optional with a new device-tree property.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220809200701.218059-4-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

hwmon: (occ) Replace open-coded variant of %*phN specifier

printf()-like functions in the kernel have extensions, such as
%*phN to dump small pieces of memory as hex bytes.

Replace custom approach with the direct use of %*phN.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220726143110.4809-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Prevent power cap command overwriting poll response

Currently, the response to the power cap command overwrites the
first eight bytes of the poll response, since the commands use
the same buffer. This means that user's get the wrong data between
the time of sending the power cap and the next poll response update.
Fix this by specifying a different buffer for the power cap command
response.

Fixes: 5b5513b88002 ("hwmon: Add On-Chip Controller (OCC) hwmon driver")
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220628203029.51747-1-eajames@linux.ibm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Lock mutex in shutdown to prevent race with occ_active

Unbinding the driver or removing the parent device at the same time
as using the OCC active sysfs file can cause the driver to unregister
the hwmon device twice. Prevent this by locking the occ mutex in the
shutdown function.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220606185455.21126-1-eajames@linux.ibm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Delay hwmon registration until user request

Instead of registering the hwmon device at probe time, use the
existing "occ_active" sysfs file to control when the driver polls
the OCC for sensor data and registers with hwmon. The reason for
this change is that the SBE, which is the device by which the
driver communicates with the OCC, cannot handle communications
during certain system state transitions, resulting in
unrecoverable system errors.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220427140443.11428-1-eajames@linux.ibm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Add soft minimum power cap attribute

Export the power caps data for the soft minimum power cap through hwmon.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20220215151022.7498-5-eajames@linux.ibm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Remove sequence numbering and checksum calculation

Checksumming of the request and sequence numbering is now done in the
OCC interface driver in order to keep unique sequence numbers. So
remove those in the hwmon driver. Also, add the command length to the
send_cmd function pointer, since the checksum must be placed in the
last two bytes of the command. The submit interface must receive the
exact size of the command - previously it could be rounded to the
nearest 8 bytes with no consequence.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210721190231.117185-3-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

hwmon: (occ) Fix P10 VRM temp sensors

The P10 (temp sensor version 0x10) doesn't do the same VRM status
reporting that was used on P9. It just reports the temperature, so
drop the check for VRM fru type in the sysfs show function, and don't
set the name to "alarm".

Fixes: db4919ec86 ("hwmon: (occ) Add new temperature sensor type")
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20210929153604.14968-1-eajames@linux.ibm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Print response status in first poll error message

In order to better debug problems starting up the driver, print
the response status from the OCC in the error logged when the first
poll command fails.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210209171235.20624-5-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

hwmon: (occ) Start sequence number at one

Initialize the sequence number at one, rather than zero, in order
to prevent false matches with the zero-initialized OCC SRAM
buffer before the OCC is fully initialized.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210209171235.20624-4-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

hwmon: (occ) Fix poll rate limiting

The poll rate limiter time was initialized at zero. This breaks the
comparison in time_after if jiffies is large. Switch to storing the
next update time rather than the previous time, and initialize the
time when the device is probed.

Fixes: c10e753d43eb ("hwmon (occ): Add sensor types and versions")
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20210429151336.18980-1-eajames@linux.ibm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: replace snprintf in show functions with sysfs_emit

coccicheck complains about the use of snprintf() in sysfs
show functions.

drivers/hwmon/ina3221.c:701:8-16: WARNING: use scnprintf or sprintf

This results in a large number of patch submissions. Fix it all in
one go using the following coccinelle rules. Use sysfs_emit instead
of scnprintf or sprintf since that makes more sense.

@depends on patch@
identifier show, dev, attr, buf;
@@

ssize_t show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
return
- snprintf(buf, \( PAGE_SIZE \| PAGE_SIZE - 1 \),
+ sysfs_emit(buf,
...);
...>
}

@depends on patch@
identifier show, dev, attr, buf, rc;
@@

ssize_t show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
rc =
- snprintf(buf, \( PAGE_SIZE \| PAGE_SIZE - 1 \),
+ sysfs_emit(buf,
...);
...>
}

While at it, remove unnecessary braces and as well as unnecessary
else after return statements to address checkpatch warnings in the
resulting patch.

Cc: Zihao Tang <tangzihao1@hisilicon.com>
Cc: Jay Fang <f.fangjian@huawei.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Add new temperature sensor type

The latest version of the On-Chip Controller (OCC) has a different
format for the temperature sensor data. Add a new temperature sensor
version to handle this data.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20201120010315.190737-4-joel@jms.id.au
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

hwmon: (occ) Fix division by zero issue

The code in occ_get_powr_avg() invokes div64_u64() without checking the
divisor. In case the divisor is zero, kernel gets an "Division by zero
in kernel" error.

Check the divisor and make it return 0 if the divisor is 0.

Fixes: c10e753d43eb ("hwmon (occ): Add sensor types and versions")
Signed-off-by: Lei YU <mine260309@gmail.com>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/1562813088-23708-1-git-send-email-mine260309@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

OCC: FSI and hwmon: Add sequence numbering

Sequence numbering of the commands submitted to the OCC is required by
the OCC interface specification. Add sequence numbering and check for
the correct sequence number on the response.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Lei YU <mine260309@gmail.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>

hwmon: (occ) Add temp sensor value check

The occ driver supports two formats for the temp sensor value.

The OCC firmware for P8 supports only the first format, for which
no range checking or error processing is performed in the driver.
Inspecting the OCC sources for P8 reveals that OCC may send
a special value 0xFFFF to indicate that a sensor read timeout
has occurred, see

https://github.com/open-power/occ/blob/master_p8/src/occ/cmdh/cmdh_fsp_cmds.c#L395

That situation wasn't handled in the driver. This patch adds invalid
temp value check for the sensor data format 1 and handles it the same
way as it is done for the format 2, where EREMOTEIO is reported for
this case.

Signed-off-by: Alexander Soldatov <a.soldatov@yadro.com>
Signed-off-by: Alexander Amelkin <a.amelkin@yadro.com>
Reviewed-by: Alexander Amelkin <a.amelkin@yadro.com>
Cc: Edward A. James <eajames@us.ibm.com>
Cc: Joel Stanley <joel@jms.id.au>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Store error condition for rate-limited polls

The OCC driver limits the rate of sending poll commands to the OCC. If a
user reads a hwmon entry after a poll response resulted in an error and
is rate-limited, the error is invisible to the user. Fix this by storing
the last error and returning that in the rate-limited case.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Move common code to a separate module

Instead of duplicating the common code into the 2 (binary) drivers,
move the common code to a separate module. This is cleaner.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Eddie James <eajames@linux.ibm.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Tested-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Fix power sensor indexing

In the case of power sensor version 0xA0, the sensor indexing overlapped
with the "caps" power sensors, resulting in probe failure and kernel
warnings. Fix this by specifying the next index for each power sensor
version.

Fixes: 54076cb3b5ff ("hwmon (occ): Add sensor attributes and register ...")
Cc: stable@vger.kernel.org
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Fix license headers

Files have inconsistent license information.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: (occ) Fix potential integer overflow

Cast get_unaligned_be32(...) to u64 in order to give the compiler
complete information about the proper arithmetic to use and avoid
a potential integer overflow.

Notice that such function call is used in contexts that expect
expressions of type u64 (64 bits, unsigned); and the following
expressions are currently being evaluated using 32-bit
arithmetic:

val = get_unaligned_be32(&power->update_tag) *
occ->powr_sample_time_us;

val = get_unaligned_be32(&power->vdn.update_tag) *
occ->powr_sample_time_us;

Addresses-Coverity-ID: 1442357 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1442476 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1442508 ("Unintentional integer overflow")
Fixes: ff692d80b2e2 ("hwmon (occ): Add sensor types and versions")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon (occ): Add sysfs attributes for additional OCC data

The OCC provides a variety of additional information about the state of
the host processor, such as throttling, error conditions, and the number
of OCCs detected in the system. This information is essential to service
processor applications such as fan control and host management.
Therefore, export this data in the form of sysfs attributes attached to
the platform device (to which the hwmon device is also attached).

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon (occ): Add sensor attributes and register hwmon device

Setup the sensor attributes for every OCC sensor found by the first poll
response. Register the attributes with hwmon.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon (occ): Add sensor types and versions

Add structures to define all sensor types and versions. Add sysfs show
and store functions for each sensor type. Add a method to construct the
"set user power cap" command and send it to the OCC. Add rate limit to
polling the OCC (in case user-space reads our hwmon entries rapidly).

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon (occ): Parse OCC poll response

Add method to parse the response from the OCC poll command. This only
needs to be done during probe(), since the OCC shouldn't change the
number or format of sensors while it's running. The parsed response
allows quick access to sensor data, as well as information on the
number and version of sensors, which we need to instantiate hwmon
attributes.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

hwmon: Add On-Chip Controller (OCC) hwmon driver

The OCC is a device embedded on a POWER processor that collects and
aggregates sensor data from the processor and system. The OCC can
provide the raw sensor data as well as perform thermal and power
management on the system.

This driver provides a hwmon interface to the OCC from a service
processor (e.g. a BMC). The driver supports both POWER8 and POWER9 OCCs.
Communications with the POWER8 OCC are established over standard I2C
bus. The driver communicates with the POWER9 OCC through the FSI-based
OCC driver, which handles the lower-level communication details.

This patch lays out the structure of the OCC hwmon driver. There are two
platform drivers, one each for P8 and P9 OCCs. These are probed through
the I2C tree and the FSI-based OCC driver, respectively. The patch also
defines the first common structures and methods between the two OCC
versions.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
[groeck: Fix up SPDX license identifier]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>