Driver can receive HW not ready interrupt unexpectedly.
E.g. for cards that go donwn to D3cold.
Trigger link reset in this case to synchronize driver and
firmware state.
No need to do that sync if driver is going down or interrupt is
received before driver started initial link reset sequence.
Introduce UNINITIALIZED device state to allow interrupt handler
to ignore interrupts before first init.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250918130435.3327400-2-alexander.usyskin@intel.com
mei_device lifetime was managed by devm procedure of parent device.
But such memory is freed on device_del.
Mei_device object is used by client object that may be alive after
parent device is removed.
It may lead to use-after-free if discrete graphics driver unloads
mei_gsc auxiliary device while user-space holds open handle to mei
character device.
Connect mei_device structure lifteme to mei class device lifetime
by adding mei_device free to class device remove callback.
Move exising parent device pointer to separate field in mei_device
to avoid misuse.
Allocate character device dynamically and allow to control its own
lifetime as it may outlive mei_device structure while character
device closes after parent device is removed from the system.
Leave power management on parent device as we overwrite pci runtime
pm procedure and user-space is expecting it there.
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14201
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://lore.kernel.org/r/20250826125617.1166546-1-alexander.usyskin@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
GSC devices perform legal firmware initiated resets due to state transition
that may appear as unexpected to the driver. Lower the log level for those
devices to debug level and save the firmware status registers.
When the device comes out of the reset it is possible to check whether the
resets was due to a firmware error or an exception
and only than produce a warning.
Signed-off-by: Vitaly Lubart <vitaly.lubart@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20231015080540.95922-1-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During the hardware start sequence, do not overwrite the driver state
and do not proceed with the initialization sequence if the state
was changed while the driver was waiting for the start interrupt.
This can happen if the driver's removal/stop procedure was triggered
from the parent level while the driver is waiting for the start
interrupt. This may lead to stray the reset work or the timer
after driver were removed.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20220215080438.264876-4-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Expose mei device state to user-space through sysfs.
This gives indication to applications that driver is in transition,
usefully mostly to detect link reset state.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use unified version of the copyright notice in the files
Update copyright years according the year the files
were touched, except this patch and SPDX conversions.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Replace boiler plate licenses texts with the SPDX license
identifiers in the mei files header.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Implement circular buffer protocol over receive dma
buffer. Add extension to the mei message header that holds
length of the buffer on the dma buffer.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Limit the number of queued writes per client.
Writes above this threshold are blocked till place
in the transmit queue is available.
The limit is configurable via sysfs and defaults to 50.
The implementation should provide blocking I/O behavior.
Prior to this change one would end up in the hands of OOM.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When mei driver is powering down due to suspend or shutdown
it will iterate over the mei client bus and disconnect
each client device attached in turn.
The power down flow consist of the link rest, which causes all clients
get disconnected at once, hence the individual disconnection
can be omitted and significantly reduce power down flow.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
AMTHIF has special support in the mei drive, it handles multiplexing
multiple user space connection above single me client connection.
Since there is no additional addressing information there is a strict
requirement on the traffic order on each connection and on the "read
after write" order within the connection. This creates a lot of
complexity mostly because the other client types do not necessarily fall
under the same restriction. After carefully studying the use of the
AMTHIF client, we came to conclusion that the multiplexing is not really
utilized by any application and we may safely remove that support and
significantly simplify the driver.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
