The raw message frame length is unaligned and explicitly marked as
little endian. It should not be accessed without the appropriate
accessor functions. Fix this.
Note that payload.len already contains the correct length after parsing
via sshp_parse_frame(), so we can simply use that instead.
Reported-by: kernel-test-robot <lkp@intel.com>
Fixes: c167b9c7e3 ("platform/surface: Add Surface Aggregator subsystem")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Acked-by: Mark Gross <mgross@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210211124149.2439007-1-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
The braces of the unlikely() macro inside the if condition only cover
the subtraction part, not the whole statement. This causes the result of
the subtraction to be converted to zero or one. While that still works
in this context, it causes static analysis tools to complain (and is
just plain wrong).
Fix the bracket placement and, while at it, simplify the if-condition.
Also add a comment to the if-condition explaining what we expect the
result to be and what happens on the failure path, as it seems to have
caused a bit of confusion.
This commit should not cause any difference in behavior or generated
code.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: c167b9c7e3 ("platform/surface: Add Surface Aggregator subsystem")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210126172202.1428367-1-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Both, ssh_rtl_rx_start() and ssh_rtl_tx_start() functions, do not exist
and have been consolidated into ssh_rtl_start(). Nevertheless,
kernel-doc references the former functions. Replace those references
with references to ssh_rtl_start().
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210114150826.19109-1-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
A function has a different name between their prototype
and its kernel-doc markup:
../drivers/platform/surface/aggregator/ssh_request_layer.c:1065: warning: expecting prototype for ssh_rtl_tx_start(). Prototype was for ssh_rtl_start() instead
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/4a6bf33cfbd06654d78294127f2b6d354d073089.1610610937.git.mchehab+huawei@kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
The Surface Aggregator EC provides varying functionality, depending on
the Surface device. To manage this functionality, we use dedicated
client devices for each subsystem or virtual device of the EC. While
some of these clients are described as standard devices in ACPI and the
corresponding client drivers can be implemented as platform drivers in
the kernel (making use of the controller API already present), many
devices, especially on newer Surface models, cannot be found there.
To simplify management of these devices, we introduce a new bus and
client device type for the Surface Aggregator subsystem. The new device
type takes care of managing the controller reference, essentially
guaranteeing its validity for as long as the client device exists, thus
alleviating the need to manually establish device links for that purpose
in the client driver (as has to be done with the platform devices).
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20201221183959.1186143-7-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
This commit adds error injection hooks to the Surface Serial Hub
communication protocol implementation, to:
- simulate simple serial transmission errors,
- drop packets, requests, and responses, simulating communication
failures and potentially trigger retransmission timeouts, as well as
- inject invalid data into submitted and received packets.
Together with the trace points introduced in the previous commit, these
facilities are intended to aid in testing, validation, and debugging of
the Surface Aggregator communication layer.
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/20201221183959.1186143-6-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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>
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>
Surface Serial Hub communication is, in its core, packet based. Each
sequenced packet requires to be acknowledged, via an ACK-type control
packet. In case invalid data has been received by the driver, a NAK-type
(not-acknowledge/negative acknowledge) control packet is sent,
triggering retransmission.
Control packets are therefore a core communication primitive and used
frequently enough (with every sequenced packet transmission sent by the
embedded controller, including events and request responses) that it may
warrant caching their allocations to reduce possible memory
fragmentation.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20201221183959.1186143-3-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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>
