There be should check return value from dma_set_mask to throw some info
if fail to set dma mask.

Detected by CoverityScan, CID# 1443983:  Error handling issues (CHECKED_RETURN)

Fixes: f6f9279f2bf0 ("misc: fastrpc: Add Qualcomm fastrpc basic driver model")
Signed-off-by: Bo YU <tsu.yubo@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In case of error, the function dma_buf_get() returns ERR_PTR() and never
returns NULL. The NULL test in the return value check should be replaced
with IS_ERR().

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This change fixes fastrpc_device_open() when no session is available and
return an error in such case.

Signed-off-by: Thierry Escande <thierry.escande@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

User process can involve dealing with big buffer sizes, and also passing
buffers from one compute context bank to other compute context bank for
complex dsp algorithms.

This patch adds support to fastrpc to make it a proper dmabuf exporter
to avoid making copies of buffers.

Co-developed-by: Thierry Escande <thierry.escande@linaro.org>
Signed-off-by: Thierry Escande <thierry.escande@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch adds support to create or attach remote shell process.
The shell process called fastrpc_shell_0 is usually loaded on the DSP
when a user process is spawned.

Most of the work is derived from various downstream Qualcomm kernels.
Credits to various Qualcomm authors who have contributed to this code.
Specially Tharun Kumar Merugu <mtharu@codeaurora.org>

Co-developed-by: Thierry Escande <thierry.escande@linaro.org>
Signed-off-by: Thierry Escande <thierry.escande@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch adds support to compute context invoke method on the
remote processor (DSP).
This involves setting up the functions input and output arguments,
input and output handles and mapping the dmabuf fd for the
argument/handle buffers.

The below diagram depicts invocation of a single method where the
client and objects reside on different processors. An object could
expose multiple methods which can be grouped together and referred
to as an interface.

,--------,        ,------,  ,-----------,  ,------,        ,--------,
|        | method |      |  |           |  |      | method |        |
| Client |------->| Stub |->| Transport |->| Skel |------->| Object |
|        |        |      |  |           |  |      |        |        |
`--------`        `------`  `-----------`  `------`        `--------`

Client:    Linux user mode process that initiates the remote invocation
Stub:      Auto generated code linked in with the user mode process that
           takes care of marshaling parameters
Transport: Involved in carrying an invocation from a client to an
           object. This involves two portions: 1) FastRPC Linux
           kernel driver that receives the remote invocation, queues
           them up and then waits for the response after signaling the
           remote side. 2) Service running on the remote side that
           dequeues the messages from the queue and dispatches them for
           processing.
Skel:      Auto generated code that takes care of un-marshaling
           parameters
Object:    Method implementation

Most of the work is derived from various downstream Qualcomm kernels.
Credits to various Qualcomm authors who have contributed to this code.
Specially Tharun Kumar Merugu <mtharu@codeaurora.org>

Co-developed-by: Thierry Escande <thierry.escande@linaro.org>
Signed-off-by: Thierry Escande <thierry.escande@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch adds basic driver model for Qualcomm FastRPC driver which
implements an IPC (Inter-Processor Communication) mechanism that
allows for clients to transparently make remote method invocations
across processor boundaries.

Each DSP rpmsg channel is represented as fastrpc channel context and
is exposed as a character device for userspace interface.
Each compute context bank is represented as fastrpc-session-context,
which are dynamically managed by the channel context char device.

Co-developed-by: Thierry Escande <thierry.escande@linaro.org>
Signed-off-by: Thierry Escande <thierry.escande@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>