The SCMI protocol can be used to get power estimates from firmware
corresponding to each performance state of a device. Although these power
costs are already managed by the SCMI firmware driver, they are not
exposed to any external subsystem yet.
Fix this by adding a new get_power() interface to the exisiting perf_ops
defined for the SCMI protocol.
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Replace all the memcpy() for copying name strings from the firmware with
strlcpy() to make sure we are bounded by the source buffer size and we
also always have NULL-terminated strings.
This is needed to avoid out of bounds accesses if the firmware returns
a non-terminated string.
Reported-by: Olof Johansson <olof@lixom.net>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Firmware can provide zero as values for sustained performance level and
corresponding sustained frequency in kHz in order to hide the actual
frequencies and provide only abstract values. It may endup with divide
by zero scenario resulting in kernel panic.
Let's set the multiplication factor to one if either one or both of them
(sustained_perf_level and sustained_freq) are set to zero.
Fixes: a9e3fbfaa0 ("firmware: arm_scmi: add initial support for performance protocol")
Reported-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
The "pi->dom_info" buffer is allocated in init() and it can't be NULL
here. These tests are sort of weird as well because if "pi->dom_info"
was NULL but "domain" was non-zero then it would lead to an Oops.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Just after the initial patches were queued, Jonathan Cameron mentioned
that scmi_one_xfer_{get_put} were not very clear and suggested to use
scmi_xfer_{alloc,free}. While I agree to some extent, the reason not to
have alloc/free as these are preallocated buffers and these functions
just returns a reference to free slot in that preallocated array.
However it was agreed to drop "_one" as it's implicit that we are always
dealing with one slot anyways.
This patch updates the name accordingly dropping "_one" in both {get,put}
functions. Also scmi_one_xfer_init is renamed as scmi_xfer_get_init to
reflect the fact that it gets the free slots and then initialise it.
Reported-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Most of the scmi code follows the suggestion from Greg KH on a totally
different thread[0] to have the subsystem name first, followed by the
noun and finally the verb with couple of these exceptions.
This patch fixes them so that all the functions names are aligned to
that practice.
[0] https://www.spinics.net/lists/arm-kernel/msg583673.html
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
In order to implement fast CPU DVFS switching, we need to perform all
DVFS operations atomically. Since SCMI transfer already provide option
to choose between pooling vs interrupt driven(default), we can opt for
polling based transfers for set,get performance domain operations.
This patch adds option to choose between polling vs interrupt driven
SCMI transfers for set,get performance level operations.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
The performance protocol is intended for the performance management of
group(s) of device(s) that run in the same performance domain. It
includes even the CPUs. A performance domain is defined by a set of
devices that always have to run at the same performance level.
For example, a set of CPUs that share a voltage domain, and have a
common frequency control, is said to be in the same performance domain.
The commands in this protocol provide functionality to describe the
protocol version, describe various attribute flags, set and get the
performance level of a domain. It also supports discovery of the list
of performance levels supported by a performance domain, and the
properties of each performance level.
This patch adds basic support for the performance protocol.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
