[media] v4l: ti-vpe: Create a vpdma helper library
The primary function of VPDMA is to move data between external memory
and internal processing modules(in our case, VPE) that source or sink
data. VPDMA is capable of buffering this data and then delivering the
data as demanded to the modules as programmed. The modules that source
or sink data are referred to as clients or ports. A channel is setup
inside the VPDMA to connect a specific memory buffer to a specific
client. The VPDMA centralizes the DMA control functions and buffering
required to allow all the clients to minimize the effect of long latency
times.
Add the following to the VPDMA helper:
- A data struct which describe VPDMA channels. For now, these channels
are the ones used only by VPE, the list of channels will increase when
VIP(Video Input Port) also uses the VPDMA library. This channel
information will be used to populate fields required by data
descriptors.
- Data structs which describe the different data types supported by
VPDMA. This data type information will be used to populate fields
required by data descriptors and used by the VPE driver to map a V4L2
format to the corresponding VPDMA data type.
- Provide VPDMA register offset definitions, functions to read, write
and modify VPDMA registers.
- Functions to create and submit a VPDMA list. A list is a group of
descriptors that makes up a set of DMA transfers that need to be
completed. Each descriptor will either perform a DMA transaction to
fetch input buffers and write to output buffers(data descriptors), or
configure the MMRs of sub blocks of VPE(configuration descriptors), or
provide control information to VPDMA (control descriptors).
- Functions to allocate, map and unmap buffers needed for the descriptor
list, payloads containing MMR values and scaler coefficients. These use
the DMA mapping APIs to ensure exclusive access to VPDMA.
- Functions to enable VPDMA interrupts. VPDMA can trigger an interrupt
on the VPE interrupt line when a descriptor list is parsed completely
and the DMA transactions are completed. This requires masking the events
in VPDMA registers and configuring some top level VPE interrupt
registers.
- Enable some VPDMA specific parameters: frame start event(when to start
DMA for a client) and line mode(whether each line fetched should be
mirrored or not).
- Function to load firmware required by VPDMA. VPDMA requires a firmware
for it's internal list manager. We add the required request_firmware
apis to fetch this firmware from user space.
- Function to dump VPDMA registers.
- A function to initialize and create a VPDMA instance, this will be
called by the VPE driver with it's platform device pointer, this
function will take care of loading VPDMA firmware and returning a
vpdma_data instance back to the VPE driver. The VIP driver will also
call the same init function to initialize it's own VPDMA instance.
Signed-off-by: Archit Taneja <archit@ti.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
3 files changed