platform/surface: aggregator: Allow completion work-items to be executed in parallel

Currently, event completion work-items are restricted to be run strictly
in non-parallel fashion by the respectiv

platform/surface: aggregator: Allow completion work-items to be executed in parallel

Currently, event completion work-items are restricted to be run strictly
in non-parallel fashion by the respective workqueue. However, this has
lead to some problems:

In some instances, the event notifier function called inside this
completion workqueue takes a non-negligible amount of time to execute.
One such example is the battery event handling code (surface_battery.c),
which can result in a full battery information refresh, involving
further synchronous communication with the EC inside the event handler.
This is made worse if the communication fails spuriously, generally
incurring a multi-second timeout.

Since the event completions are run strictly non-parallel, this blocks
other events from being propagated to the respective subsystems. This
becomes especially noticeable for keyboard and touchpad input, which
also funnel their events through this system. Here, users have reported
occasional multi-second "freezes".

Note, however, that the event handling system was never intended to run
purely sequentially. Instead, we have one work struct per EC/SAM
subsystem, processing the event queue for that subsystem. These work
structs were intended to run in parallel, allowing sequential processing
of work items for each subsystem but parallel processing of work items
across subsystems.

The only restriction to this is the way the workqueue is created.
Therefore, replace create_workqueue() with alloc_workqueue() and do not
restrict the maximum number of parallel work items to be executed on
that queue, resolving any cross-subsystem blockage.

Fixes: c167b9c7e3d6 ("platform/surface: Add Surface Aggregator subsystem")
Link: https://github.com/linux-surface/linux-surface/issues/1026
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20230525210110.2785470-1-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Rename top-level request functions to avoid ambiguities

We currently have a struct ssam_request_sync and a function
ssam_request_sync(). While this is valid C, there ar

platform/surface: aggregator: Rename top-level request functions to avoid ambiguities

We currently have a struct ssam_request_sync and a function
ssam_request_sync(). While this is valid C, there are some downsides to
it.

One of these is that current Sphinx versions (>= 3.0) cannot
disambiguate between the two (see disucssion and pull request linked
below). It instead emits a "WARNING: Duplicate C declaration" and links
for the struct and function in the resulting documentation link to the
same entry (i.e. both to either function or struct documentation)
instead of their respective own entries.

While we could just ignore that and wait for a fix, there's also a point
to be made that the current naming can be somewhat confusing when
searching (e.g. via grep) or trying to understand the levels of
abstraction at play:

We currently have struct ssam_request_sync and associated functions
ssam_request_sync_[alloc|free|init|wait|...]() operating on this struct.
However, function ssam_request_sync() is one abstraction level above
this. Similarly, ssam_request_sync_with_buffer() is not a function
operating on struct ssam_request_sync, but rather a sibling to
ssam_request_sync(), both using the struct under the hood.

Therefore, rename the top level request functions:

ssam_request_sync() -> ssam_request_do_sync()
ssam_request_sync_with_buffer() -> ssam_request_do_sync_with_buffer()
ssam_request_sync_onstack() -> ssam_request_do_sync_onstack()

Link: https://lore.kernel.org/all/085e0ada65c11da9303d07e70c510dc45f21315b.1656756450.git.mchehab@kernel.org/
Link: https://github.com/sphinx-doc/sphinx/pull/8313
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20221220175608.1436273-2-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Improve documentation and handling of message target and source IDs

The `tid_in` and `tid_out` fields of the serial hub protocol command
struct (struct ssh_command) are

platform/surface: aggregator: Improve documentation and handling of message target and source IDs

The `tid_in` and `tid_out` fields of the serial hub protocol command
struct (struct ssh_command) are actually source and target IDs,
indicating the peer from which the message originated and the peer for
which it is intended.

Change the naming of those fields accordingly and improve the protocol
documentation. Additionally, introduce an enum containing all currently
known peers, i.e. targets and sources.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20221202223327.690880-3-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Add missing call to ssam_request_sync_free()

Although rare, ssam_request_sync_init() can fail. In that case, the
request should be freed via ssam_request_sync_free(). C

platform/surface: aggregator: Add missing call to ssam_request_sync_free()

Although rare, ssam_request_sync_init() can fail. In that case, the
request should be freed via ssam_request_sync_free(). Currently it is
leaked instead. Fix this.

Fixes: c167b9c7e3d6 ("platform/surface: Add Surface Aggregator subsystem")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20221220175608.1436273-1-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: Update copyright year of various drivers

Update the copyright of various Surface drivers to the current year.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https:/

platform/surface: Update copyright year of various drivers

Update the copyright of various Surface drivers to the current year.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220624205800.1355621-4-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Allow notifiers to avoid communication on unregistering

When SSAM client devices have been (physically) hot-removed,
communication attempts with those devices may fail

platform/surface: aggregator: Allow notifiers to avoid communication on unregistering

When SSAM client devices have been (physically) hot-removed,
communication attempts with those devices may fail and time out. This
can even extend to event notifiers, due to which timeouts may occur
during device removal, slowing down that process.

Add a parameter to the notifier unregister function that allows skipping
communication with the EC to prevent this. Furthermore, add wrappers for
registering and unregistering notifiers belonging to SSAM client devices
that automatically check if the device has been marked as hot-removed
and communication should be avoided.

Note that non-SSAM client devices can generally not be hot-removed, so
also add a convenience wrapper for those, defaulting to allow
communication.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220527023447.2460025-4-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Drop unnecessary variable initialization

The status variable in ssam_controller_event_disable() is always set, no
need to initialize it.

Signed-off-by: Maximilian Luz

platform/surface: aggregator: Drop unnecessary variable initialization

The status variable in ssam_controller_event_disable() is always set, no
need to initialize it.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210604210907.25738-3-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Do not return uninitialized value

The status variable in ssam_nf_refcount_disable_free() is only set when
the reference count equals zero. Otherwise, it is returned
uni

platform/surface: aggregator: Do not return uninitialized value

The status variable in ssam_nf_refcount_disable_free() is only set when
the reference count equals zero. Otherwise, it is returned
uninitialized. Fix this by always initializing status to zero.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 640ee17199e4 ("platform/surface: aggregator: Allow enabling of events without notifiers")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210604210907.25738-2-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Update copyright

It's 2021, update the copyright accordingly.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>

platform/surface: aggregator: Update copyright

It's 2021, update the copyright accordingly.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210604134755.535590-4-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Allow enabling of events without notifiers

We can already enable and disable SAM events via one of two ways: either
via a (non-observer) notifier tied to a specific eve

platform/surface: aggregator: Allow enabling of events without notifiers

We can already enable and disable SAM events via one of two ways: either
via a (non-observer) notifier tied to a specific event group, or a
generic event enable/disable request. In some instances, however,
neither method may be desirable.

The first method will tie the event enable request to a specific
notifier, however, when we want to receive notifications for multiple
event groups of the same target category and forward this to the same
notifier callback, we may receive duplicate events, i.e. one event per
registered notifier. The second method will bypass the internal
reference counting mechanism, meaning that a disable request will
disable the event regardless of any other client driver using it, which
may break the functionality of that driver.

To address this problem, add new functions that allow enabling and
disabling of events via the event reference counting mechanism built
into the controller, without needing to register a notifier.

This can then be used in combination with observer notifiers to process
multiple events of the same target category without duplication in the
same callback function.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210604134755.535590-3-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Allow registering notifiers without enabling events

Currently, each SSAM event notifier is directly tied to one group of
events. This makes sense as registering a notif

platform/surface: aggregator: Allow registering notifiers without enabling events

Currently, each SSAM event notifier is directly tied to one group of
events. This makes sense as registering a notifier will automatically
take care of enabling the corresponding event group and normally drivers
only need notifications for a very limited number of events, associated
with different callbacks for each group.

However, there are rare cases, especially for debugging, when we want to
get notifications for a whole event target category instead of just a
single group of events in that category. Registering multiple notifiers,
i.e. one per group, may be infeasible due to two issues: a) we might not
know every event enable/disable specification as some events are
auto-enabled by the EC and b) forwarding this to the same callback will
lead to duplicate events as we might not know the full event
specification to perform the appropriate filtering.

This commit introduces observer-notifiers, which are notifiers that are
not tied to a specific event group and do not attempt to manage any
events. In other words, they can be registered without enabling any
event group or incrementing the corresponding reference count and just
act as silent observers, listening to all currently/previously enabled
events based on their match-specification.

Essentially, this allows us to register one single notifier for a full
event target category, meaning that we can process all events of that
target category in a single callback without duplication. Specifically,
this will be used in the cdev debug interface to forward events to
user-space via a device file from which the events can be read.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210604134755.535590-2-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Fix event disable function

Disabling events silently fails due to the wrong command ID being used.
Instead of the command ID for the disable call, the command ID for th

platform/surface: aggregator: Fix event disable function

Disabling events silently fails due to the wrong command ID being used.
Instead of the command ID for the disable call, the command ID for the
enable call was being used. This causes the disable call to enable the
event instead. As the event is already enabled when we call this
function, the EC silently drops this command and does nothing.

Use the correct command ID for disabling the event to fix this.

Fixes: c167b9c7e3d6 ("platform/surface: Add Surface Aggregator subsystem")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210603000636.568846-1-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Fix event disable function

Disabling events silently fails due to the wrong command ID being used.
Instead of the command ID for the disable call, the command ID for th

platform/surface: aggregator: Fix event disable function

Disabling events silently fails due to the wrong command ID being used.
Instead of the command ID for the disable call, the command ID for the
enable call was being used. This causes the disable call to enable the
event instead. As the event is already enabled when we call this
function, the EC silently drops this command and does nothing.

Use the correct command ID for disabling the event to fix this.

Fixes: c167b9c7e3d6 ("platform/surface: Add Surface Aggregator subsystem")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210603000636.568846-1-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Do not mark interrupt as shared

Having both IRQF_NO_AUTOEN and IRQF_SHARED set causes
request_threaded_irq() to return with -EINVAL (see comment in flag
validation in t

platform/surface: aggregator: Do not mark interrupt as shared

Having both IRQF_NO_AUTOEN and IRQF_SHARED set causes
request_threaded_irq() to return with -EINVAL (see comment in flag
validation in that function). As the interrupt is currently not shared
between multiple devices, drop the IRQF_SHARED flag.

Fixes: 507cf5a2f1e2 ("platform/surface: aggregator: move to use request_irq by IRQF_NO_AUTOEN flag")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210505133635.1499703-1-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: fix a bit test

The "funcs" variable is a u64. If "func" is more than 31 then the
BIT() shift will wrap instead of testing the high bits.

Fixes: c167b9c7e3d6 ("platfor

platform/surface: aggregator: fix a bit test

The "funcs" variable is a u64. If "func" is more than 31 then the
BIT() shift will wrap instead of testing the high bits.

Fixes: c167b9c7e3d6 ("platform/surface: Add Surface Aggregator subsystem")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/YH6UUhJhGk3mk13b@mwanda
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: move to use request_irq by IRQF_NO_AUTOEN flag

disable_irq() after request_irq() still has a time gap in which
interrupts can come. request_irq() with IRQF_NO_AUTOEN fl

platform/surface: aggregator: move to use request_irq by IRQF_NO_AUTOEN flag

disable_irq() after request_irq() still has a time gap in which
interrupts can come. request_irq() with IRQF_NO_AUTOEN flag will
disable IRQ auto-enable because of requesting.

this patch is made base on "add IRQF_NO_AUTOEN for request_irq" which
is being merged: https://lore.kernel.org/patchwork/patch/1388765/

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/1617778852-26492-1-git-send-email-tiantao6@hisilicon.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Make SSAM_DEFINE_SYNC_REQUEST_x define static functions

The SSAM_DEFINE_SYNC_REQUEST_x() macros are intended to reduce
boiler-plate code for SSAM request definitions by

platform/surface: aggregator: Make SSAM_DEFINE_SYNC_REQUEST_x define static functions

The SSAM_DEFINE_SYNC_REQUEST_x() macros are intended to reduce
boiler-plate code for SSAM request definitions by defining a wrapper
function for the specified request. The client device variants of those
macros, i.e. SSAM_DEFINE_SYNC_REQUEST_CL_x() in particular rely on the
multi-device (MD) variants, e.g.:

#define SSAM_DEFINE_SYNC_REQUEST_CL_R(name, rtype, spec...) \
SSAM_DEFINE_SYNC_REQUEST_MD_R(__raw_##name, rtype, spec) \
int name(struct ssam_device *sdev, rtype *ret) \
{ \
return __raw_##name(sdev->ctrl, sdev->uid.target, \
sdev->uid.instance, ret); \
}

This now creates the problem that it is not possible to declare the
generated functions static via

static SSAM_DEFINE_SYNC_REQUEST_CL_R(...)

as this will only apply to the function defined by the multi-device
macro, i.e. SSAM_DEFINE_SYNC_REQUEST_MD_R(). Thus compiling with
`-Wmissing-prototypes' rightfully complains that there is a 'static'
keyword missing.

To solve this, make all SSAM_DEFINE_SYNC_REQUEST_x() macros define
static functions. Non-client-device macros are also changed for
consistency. In general, we expect those functions to be only used
locally in the respective drivers for the corresponding interfaces, so
having to define a wrapper function to be able to export this should be
the odd case out.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: b78b4982d763 ("platform/surface: Add platform profile driver")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210304190524.1172197-1-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Add trace points

Add trace points to the Surface Aggregator subsystem core. These trace
points can be used to track packets, requests, and allocations. They are
further

platform/surface: aggregator: Add trace points

Add trace points to the Surface Aggregator subsystem core. These trace
points can be used to track packets, requests, and allocations. They are
further intended for debugging and testing/validation, specifically in
combination with the error injection capabilities introduced in the
subsequent commit.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20201221183959.1186143-5-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: aggregator: Add event item allocation caching

Event items are used for completing Surface Aggregator EC events, i.e.
placing event command data and payload on a workqueue for later

platform/surface: aggregator: Add event item allocation caching

Event items are used for completing Surface Aggregator EC events, i.e.
placing event command data and payload on a workqueue for later
processing to avoid doing said processing directly on the receiver
thread. This means that event items are allocated for each incoming
event, regardless of that event being transmitted via sequenced or
unsequenced packets.

On the Surface Book 3 and Surface Laptop 3, touchpad HID input events
(unsequenced), can constitute a larger amount of traffic, and therefore
allocation of event items. This warrants caching event items to reduce
memory fragmentation. The size of the cached objects is specifically
tuned to accommodate keyboard and touchpad input events and their
payloads on those devices. As a result, this effectively also covers
most other event types. In case of a larger event payload, event item
allocation will fall back to kzalloc().

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20201221183959.1186143-4-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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platform/surface: Add Surface Aggregator subsystem

Add Surface System Aggregator Module core and Surface Serial Hub driver,
required for the embedded controller found on Microsoft Surface devices.

platform/surface: Add Surface Aggregator subsystem

Add Surface System Aggregator Module core and Surface Serial Hub driver,
required for the embedded controller found on Microsoft Surface devices.

The Surface System Aggregator Module (SSAM, SAM or Surface Aggregator)
is an embedded controller (EC) found on 4th and later generation
Microsoft Surface devices, with the exception of the Surface Go series.
This EC provides various functionality, depending on the device in
question. This can include battery status and thermal reporting (5th and
later generations), but also HID keyboard (6th+) and touchpad input
(7th+) on Surface Laptop and Surface Book 3 series devices.

This patch provides the basic necessities for communication with the SAM
EC on 5th and later generation devices. On these devices, the EC
provides an interface that acts as serial device, called the Surface
Serial Hub (SSH). 4th generation devices, on which the EC interface is
provided via an HID-over-I2C device, are not supported by this patch.

Specifically, this patch adds a driver for the SSH device (device HID
MSHW0084 in ACPI), as well as a controller structure and associated API.
This represents the functional core of the Surface Aggregator kernel
subsystem, introduced with this patch, and will be expanded upon in
subsequent commits.

The SSH driver acts as the main attachment point for this subsystem and
sets-up and manages the controller structure. The controller in turn
provides a basic communication interface, allowing to send requests from
host to EC and receiving the corresponding responses, as well as
managing and receiving events, sent from EC to host. It is structured
into multiple layers, with the top layer presenting the API used by
other kernel drivers and the lower layers modeled after the serial
protocol used for communication.

Said other drivers are then responsible for providing the (Surface model
specific) functionality accessible through the EC (e.g. battery status
reporting, thermal information, ...) via said controller structure and
API, and will be added in future commits.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20201221183959.1186143-2-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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