The stall timer worker checks periodically if there is a stalled i/o
transaction. The issue with the current implementation is that the timer
is ticking also when there is no pending i/o transaction.
This patch provides a simple change that prevents rescheduling
of the delayed work when there is no pending i/o.

Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

mei_amthif_read have only one difference from mei_read, it is not
calling mei_read_start().
Make mei_read_start return immediately for amthif client and drop the
special mei_amthif_read function.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

With the introduction of the receive control flow credits prefixed with
rx_ we add tx_ prefix to the variables and function used for tracking
the transmit control flow credits.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use RX flow control counter in the host client structure to
track the number of simultaneous outstanding reads.
This eliminates search in queues and makes ground for
enabling for parallel read.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Store the file associated with a client in the host client structure,
this enables dropping the special amthif client file pointer from struct
mei_device, and this is also a preparation for changing the way rx
packet allocation for fixed_address clients
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

iamthif_current_cb was used in request cancel in amthif code.
Now a canceled request is discarded only at the end of the processing
and the variable lost its purpose and can be safely removed.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

AMTHIF code now uses read completed queue to store replies from the FW.
It is possible to send the next request as soon as a read from the FW is
completed. With these changes we don't need the READ_COMPLETE state.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The control messages are usually small, around 8 bytes, and can be
allocated on the stack.
Using on stack allocation allows us to drop 'wr_msg' a rather large
buffer reserved in the mei_dev structure and relax contention
of this device global buffer.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When a message is received and amthif client is not in reading state
the message is ignored and left dangling in the queue. This may happen
after one of the amthif host connections is closed w/o completing the
reading. Another client will pick up a wrong message on next read
attempt which will lead to link reset.
To prevent this the driver has to properly discard the message when
amthif client is not in reading state.

Cc: <stable@vger.kernel.org> #4.2+
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Global me_client_index is used only during the enumeration process and
can be effectively replaced by me_addr data from the last enumeration
response as we always enumerate clients in the increasing order.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The amthif FW client can appear after the end of client enumeration.
Amthif host client initialization is done now at FW client discovery
time.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signal the FW that it can send an HBM enumeration answer immediately,
without waiting for FW initialization completion, meaning before
all the FW clients are ready and registered.

Organize enumeration response options to enum as a byproduct.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since clients can be now added and removed during runtime
we need to run bus rescan whenever me_clients list is modified.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The reserved host clients can be obsoleted now, a portion of the
platforms is shipped without iAMT enabled, where the reservation is not
relevant and for platforms with iAMT dynamic allocation is sufficient.
Dropping reserved ids makes enumeration more flexible and generic
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Enable by default connection to fixed address clients
from user-space for skylake and newer platform.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Call wake_up cl->ev_wait only in case there is no bus client registered
to the event notification.
Second, since we don't have exclusive waiter wake_up_interruptible_all
is not used correctly here.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In this particular case this more correct and safer to check if the RX
event is set in the event mask rather than query waitqueue_active
Since the check is already performed in the mei_cl_bus_rx_event
function,  it is just required to check for its return value.
Second, since we don't have exclusive waiter wake_up_interruptible_all
is not used correctly here.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now when we have per client rd_completed list we can remove
the amthif specific amthif_rd_complete_list.
In addition in the function mei_amthif_read do not loop over the
rd_completed list like the original code as the code path is unlocked.
Reviewed-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The driver uses three names file, fp, and file_object for
struct file type. To improve code clarity and adjust to my taste
rename file_object to more common and shorter fp.
Reviewed-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The struct file file pointer is used as an opaque handle to for a
connected client, for this part the pointer should be immutable and
should be set to count.
Reviewed-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since the driver now uses a list for storing read packets instead of
single variable a pending read is no longer blocking other connections.
A pending read will be discarded up the file closure.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is a possible integer overflow following by a buffer overflow
when accumulating messages coming from the FW to compose a full payload.
Occurrence of wrap around has to be prevented for next message size
calculation.
For unsigned integer the addition overflow has occurred when the
result is smaller than one of the arguments.
To simplify the fix, the types of buf.size and buf_idx are set to the
same width, namely size_t also to be aligned with the type of length
parameter in file read/write ops.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of integrating the iAMT watchdog in the mei core driver
we will create a watchdog device on the mei client bus and
create a driver for it.

This patch removes the watchdog code from the mei core driver.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We left few function prototypes in the header file after
moving nfc logic to bus.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

KDoc function section start with double start:  /** instead of /*
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Its a bit odd that debugfs_create_bool() takes 'u32 *' as an argument,
when all it needs is a boolean pointer.

It would be better to update this API to make it accept 'bool *'
instead, as that will make it more consistent and often more convenient.
Over that bool takes just a byte.

That required updates to all user sites as well, in the same commit
updating the API. regmap core was also using
debugfs_{read|write}_file_bool(), directly and variable types were
updated for that to be bool as well.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NMark Brown <broonie@kernel.org>
Acked-by: NCharles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use mei_cl_bus_ for internal bus function consistently.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Enable drivers on mei client bus to subscribe
to asynchronous event notifications.
Introduce events_mask to the existing callback infrastructure
so it is possible to handle both RX and event notification.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A process can be informed about client notification also via
SIGIO with POLL_PRI event.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

mei_cl_notify_get is to be called by a host client
to wait, receive, and ack the event notification.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Only FW version 2.0 and newer support the async event
notification. For backward compatibility block the feature
if the FW version is older then 2.0
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Implement sending and reception handlers for the
async event notification hbm commands.
Add client notification book keeping data required for the messages
    notify_en to indicate whether notification is enabled
    notify_ev to indicate whether an event is pending
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

For the FW with  HBM version >= 2.0 we don't need to reset the whole
device in case of a particular client failing to connect, it is enough
to send disconnect a request to bring the device to the stable state.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

HBM version 2.0 and above allows ME clients in the system to
register/unregister after the system is fully initialized.
Clients may be added or removed after enum_resp message was
received

1. To preserve backward compatibility the driver can opt-in to receive
client add messages by setting allow_add field in enum_req

2. A new client is added upon reception of MEI_HBM_ADD_CLIENT_REQ_CMD

3. A client is removed in a lazy manner when connection request
respond with MEI_HBMS_CLIENT_NOT_FOUND status
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

MEI bus was designed around nfc and was hard to extend.
Instead of the hard coded way of adding the devices on the mei bus
we scan the whole me client list and create a device for each
eligible me client (mei_cl_bus_rescan); currently we support
only clients with single connection and fixed address clients.
NFC radio name detection is run as a fixup routine

The patch replaces handling the device list based on struct me_cl
to device list based on me_cl_devices. The creating a connection
is pushed from the device creation time to device enablement.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove the dependency on struct ndev from the nfc device
name creation function so it is possible to use it
in a fixup routine
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Split the device registration into allocation and device struct
initialization, device setup, and the final device registration.
This why it is possible to run fixups and quirks during the setup stage
on an initialized device. Each fixup routine effects do_match flag.
If the flag is set to false at the end the device won't be
registered on the bus.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of holding the list of host clients (me_cl)
we want to keep the list me client devices (mei_cl_device)
This way we can create host to me client connection only when needed.
Add list head to mei_cl_device and cl_bus_lock
Add bus_added flag to the me client (mei_me_client) to track if
the appropriate mei_cl_device was already created and is_added
flag to mei_cl_device to track if it was already added to the device
list across the bus rescans
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In the mei bus layer there is use of different variables
of driver and device types with no clear naming convention.
There are generic struct device and struct driver,
then mei_cl_{device, driver}, and finally mei_device which
in this context serves as a bus device.

The patch sets following naming convention:

the variables of type struct device remains dev
the variables of type struct driver remains drv
the variables of type struct mei_cl_device are now cldev
the variables of type struct mei_cl_driver are now cldrv
the variables of type struct mei_device are now bus, in bus
layer context
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>