spi_qsd: Add core message queue feature

Add support to use new message queue feature provided
by SPI core framework. It is having benefits of saving
code space and getting the benefits of improvements
implemented in the core. User can set the priority
of message queue at compile time.

Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
Signed-off-by: Sana Venkat Raju <c_vsana@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
spi_qsd: Add support for multiple BAM descriptors

Currently SPI driver is queuing a single BAM descriptor
at a time. The BAM engine supports queuing of multiple
transfer descriptors.

Add support to spi driver to queue multiple descriptors.

CRs-Fixed: 546346
Change-Id: Iaee9b3b362832262b75e46e19ad18552d037620b
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
Signed-off-by: Sana Venkat Raju <c_vsana@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
spi_qsd: Fix bug in multi-xfer bam mode transaction

Spi doesn't handle multiple xfer per message scenario
(eg:Rd->Wr or Wr->Rd) correctly and spi request
stuck indefinetly in while loop when total byte count
is not 0.

increment both(rx,tx) references so next bam
transaction will be queued correctly. Flush the
bam pipes after each transactions.

CRs-Fixed: 637693
Change-Id: I455df38be2f9687b1eb2a704466f6974dfb83a22
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
spi_qsd: Initialize wait queue

Due to missing initialization of wait queue
issues reported on customer builds. This patch
adds the missing wait queue initialization code.

Signed-off-by: Sana Venkat Raju <c_vsana@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>