This patch adds support to read 64-bit sensor values. This method is
used to read energy sensors and counters which are of type u64.
Signed-off-by: NShilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Parallel sensor reads could run out of async tokens due to
opal_get_sensor_data grabbing tokens but then doing the sensor
read behind a mutex, essentially serializing the (possibly
asynchronous and relatively slow) sensor read.

It turns out that the mutex isn't needed at all, not only
should the OPAL interface allow concurrent reads, the implementation
is certainly safe for that, and if any sensor we were reading
from somewhere isn't, doing the mutual exclusion in the kernel
is the wrong place to do it, OPAL should be doing it for the kernel.

So, remove the mutex.

Additionally, we shouldn't be printing out an error when we don't
get a token as the only way this should happen is if we've been
interrupted in down_interruptible() on the semaphore.
Reported-by: NRobert Lippert <rlippert@google.com>
Signed-off-by: NStewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: NCyril Bur <cyrilbur@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

OPAL returns OPAL_WRONG_STATE upon failing to provide sensor data due to
core sleeping/offline. Add a check in opal_get_sensor_data() for sensor
read failure with OPAL_WRONG_STATE return code and return -EIO.
Signed-off-by: NVipin K Parashar <vipin@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

An opal_msg of type OPAL_MSG_ASYNC_COMP contains the return code in the
params[1] struct member. However this isn't intuitive or obvious when
reading the code and requires that a user look at the skiboot
documentation or opal-api.h to verify this.

Add an inline function to get the return code from an opal_msg and update
call sites accordingly.
Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Most of the OPAL subsystems are always compiled in for PowerNV and
many of them need to be initialised before or after other OPAL
subsystems. Rather than trying to control this ordering through
machine initcalls it is clearer and easier to control initialisation
order with explicit calls in opal_init.
Signed-off-by: NAlistair Popple <alistair@popple.id.au>
Cc: Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Currently, when a sensor value is read, the kernel calls OPAL, which in
turn builds a message for the FSP, and waits for a message back.

The new device tree for OPAL sensors [1] adds new sensors that can be
read synchronously (core temperatures for instance) and that don't need
to wait for a response.

This patch modifies the opal call to accept an OPAL_SUCCESS return value
and cover the case above.

[1] https://lists.ozlabs.org/pipermail/skiboot/2015-March/000639.htmlSigned-off-by: NCédric Le Goater <clg@fr.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

OPAL has its own list of return codes. The patch provides a translation
of such codes in errnos for the opal_sensor_read call, and possibly
others if needed.
Signed-off-by: NCédric Le Goater <clg@fr.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The current driver probe() function assumes the sensor device to be
always present and gets executed every time if the driver is loaded,
but the appropriate hardware could not be present.

So, move the platform device creation as part of platform init code
and use the 'id_table' to check if the device is present or not.
Signed-off-by: NNeelesh Gupta <neelegup@linux.vnet.ibm.com>
Acked-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

One OPAL call and one device tree property needed byte swapping.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

OPAL defines opal_msg as a big endian struct so we have to
byte swap it on little endian builds.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This patch enables fetching of various platform sensor data through
OPAL and expects a sensor handle from the driver to pass to OPAL.
Signed-off-by: NNeelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>