msm: ipc: Add IPC Logging support to IPC Router

IPC Router to log debug & Router-to-Router messages onto the IPC Log
buffer. This will enable debugging the IPC Router initialization
issues and Router-to-Router communication issues, using debugfs without
logging to the kernel logs.

Change-Id: I90d968baf355f2f9abe95ea53d8b059781e8fbc6
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc: Change IPC log file name for IPC Router

Change the name of the files that contain the IPC log information
from the IPC Router. This change is done to reflect the module name
as a part of the IPC log file name.

Change-Id: I541aa5866251348b472eba6d1b3d1840500387f9
Signed-off-by: Zaheerulla Meer <zmeer@codeaurora.org>
msm: ipc: Update recvmsg operation to be non-blocking by default

Update the IPC Router recvmsg operation to be non-blocking by default
and return 0 when there is no data to read.

CRs-Fixed: 464634
Change-Id: I1f43e3a36d72312372a3ac141d506c81a613c408
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc_router: Fix potential leaks and null dereferences

Added null pointer checks to avoid potential null pointer dereferences
and free statements to avoid potential memory leaks

Change-Id: I0553dfe6c61260a700a9dc6a411dcec6483e0eb8
Signed-off-by: Brent Hronik <bhronik@codeaurora.org>
msm: ipc: Pass RESUME_TX events to the endpoints

IPC Message Router blocks the endpoints from transmission if the transmit
message count for the destination endpoint reaches the quota count. This
will cause the asynchronous message transfer to block, which violates the
defintion of asynchronous behavior.

Return -EAGAIN when the transmit message count for the destination
endpoint reaches the quota count. In addition, after receiving the
resume_tx event from the remote endpoints notify all the local endpoints
that are waiting on the remote endpoint's resume_tx event.

CRs-Fixed: 473573
Change-Id: I82b49d268394bb8c064d88fd6a2799a5e9ec566f
Signed-off-by: Zaheerulla Meer <zmeer@codeaurora.org>
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc: Do not broadcast remove client messages, if possible

Remove client message is broadcast to all subsystems within the system.
If a client has never communicated over any link, then do not send the
remove client message over any link. If a client has been communicating
only over a specific link, then send the remove client message only over
that link. If a client has been communicating over multiple links, then
broadcast the remove client message.

CRs-Fixed: 454809
Change-Id: I007c7f1ace66191ce9cbf0bad033381c4f3b750f
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc: Return -ENODEV when remote port is not found

Current implementation returns -ENOMEM when look up for a remote port
fails.

Return -ENODEV instead of -ENOMEM.

Change-Id: I7022e760631b3faaf7f1ba7952c8569905c4ee5a
Signed-off-by: Zaheerulla Meer <zmeer@codeaurora.org>
msm: ipc: Check pointer validity before dereferencing it

Transport OPEN and CLOSE events are handled by dynamically allocating a
work. Check that the work item is properly allocated before dereferencing
it.

Change-Id: Icb73548f0747494791f14f9c8014f8effd4b844c
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc: Post a packet to a local port using a common routine

A packet is posted to a local port from multiple locations within the
IPC router code. This causes the same code to be repeated in multiple
locations.

Add a common routine to perform that operation, reduce the code
redundancy and avoid any potential bug due to incomplete code repetition.

Change-Id: I4ed43feb3ea8bb88479b89814846d5ea20bb3665
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc: Refactor the code that processes control messages

process_control_msg function looks lengthy and heavily indented.

Refactor the code that processes each type of control message into a
separate function of its own.

Change-Id: Id7c4038dd4369a182ed855bd6b1e66ce07f5b8c3
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc: Cleanup unused elements

Some of the mutexes, lists and wait queues are just initialized and left
unused in IPC Router. Cleanup those unused variables/elements.

Change-Id: Ifa363afd4315f8c24eb47c74fd44ac02d0b77eff
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc: Add check to avoid integer & buffer overflow

In IPC Router configure security rule operation, add check to avoid
integer overflow and hence a buffer overflow.

CRs-Fixed: 457405
Change-Id: I5448e14242be764a7b7adfe650b2c9124701c2c5
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc: Add SMD link to interface with WCNSS

This new SMD link will enable QMI/IPC Router communication between
Application processor and WCNSS.

Change-Id: I140834bd193e110e636d3945aa5dc93b3306ef05
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc: Define locking hierarchy and use read/write semaphores

Define the hierarchy of different locks used in IPC Router. This will
help in avoiding the classic AB-BA locking scenario inside IPC Router.

Update some of the locks from mutexes to read/write semaphores. This
will help in improving parallelism. This will also improve the robustness
of the IPC Router when some of the remote subsystem stop responding
silently.

As part of the locking revamp, optimize the code path which handles
subsystem restart and cleanup some of the unused macros.

Change-Id: I2a1d81bcb90cbaf4dd5d7030efbf94f2f0758d55
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
msm: ipc: Fix potential AB-BA deadlock

In kernel QMI, while receiving responses continuously, there is a
classic out-of-order(AB-BA) deadlock scenario between IPC router and
Kernel QMI interface. The scenario is as below:

  1) IPC Router receives the message for kernel QMI port and acquires the
     corresponding port's port_rx_q_lock and then calls the notify
     function for that port which tries to acquire the handle_lock of the
     port.

  2) Kernel QMI interface, that runs independent of IPC Router activities,
     tries to send a message and acquires handle_lock for the port and
     tries to acquire the port's port_rx_q_lock to read the response from
     the port.

  3) This creates a classic AB-BA deadlock because port_rx_q_lock is
     locked at step 1 and handle_lock is acquired at step 2.

Fix the deadlock.

Change-Id: I532cff30b445e11baa715a570e5e853d9b71bab3
Signed-off-by: Zaheerulla Meer <zmeer@codeaurora.org>
msm: ipc: Make the kernel-space read operation as non-blocking

Update the read operations of kernel space to be non-blocking and
return -ENOMSG when there is no message to read.

Change-Id: I92f55d8829755078f34ff3cbe2dc9b16ed7988df
Signed-off-by: Zaheerulla Meer <zmeer@codeaurora.org>
msm: ipc: Handle the Resume_Tx events from remote endpoints

To prevent the QMI clients from flooding the remote services, IPC Router
transport supports a flow control mechanism. When the IPC Router
transport returns -EAGAIN during message transmission, queue the packet
into client's pending transaction queue for transmission during later
time. In addition, handle RESUME_TX events from the remote services and
use that event to transmit the packets in pending transaction queue.

Change-Id: Ib24256fd0dbeecb9d96ea03ffd86afe2b4cc1483
Signed-off-by: Zaheerulla Meer <zmeer@codeaurora.org>
msm: smem: Update SMEM log dump_sym to indicate QMI modules

SMEM Log dump_sym file indicates log information from QCCI/QCSI modules
as ONCRPC and log information from IPC Router as ROUTER which is
misleading.

Update the code so that dump_sym indicates correct module names.

Change-Id: I8e67ccce60780ec935cfc71d0854f156f3e922b8
Signed-off-by: Zaheerulla Meer <zmeer@codeaurora.org>
msm: ipc: Return error value on send failure

msm_ipc_router_send_msg() returns 0 instead of the error code when the
send helper function fails.

Return error code from helper function in failure cases.

Change-Id: Idef1ceef261945e30b57cd5e99fcb0b2651b31ab
Signed-off-by: Zaheerulla Meer <zmeer@codeaurora.org>
msm: ipc: Detect integer overflow before it happens

As per ANSI C Standard document, integer overflow is an undefined
behavior. So update the code to detect integer overflow before it happens.

CRs-Fixed: 491629
Change-Id: Ifd90c05266477c7734710bb94b9021f8bb9ab761
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>