TILER is a block in OMAP4's DMM which lets DSS fetch frames in a rotated manner.
Physical memory can be mapped to a portion of OMAP's system address space called
TILER address space. The TILER address space is split into 8 views. Each view
represents a rotated or mirrored form of the mapped physical memory. When a
DISPC overlay's base address is programmed to one of these views, the TILER
fetches the pixels according to the orientation of the view. A view is further
split into 4 containers, each container holds elements of a particular size.
Rotation can be achieved at the granularity of elements in the container. For
more information on TILER, refer to the Memory Subsytem section in OMAP4 TRM.
Rotation type TILER has been added which is used to exploit the capabilities of
these 8 views for performing various rotations.
When fetching from addresses mapped to TILER space, the DISPC DMA can fetch
pixels in either 1D or 2D bursts. The fetch depends on which TILER container we
are accessing. Accessing 8, 16 and 32 bit sized containers requires 2D bursts,
and page mode sized containers require 1D bursts.
The DSS2 user is expected to provide the Tiler address of the view that it is
interested in. This is passed to the paddr and p_uv_addr parameters in
omap_overlay_info. It is also expected to provide the stride value based on the
view's orientation and container type, this should be passed to the screen_width
parameter of omap_overlay_info. In calc_tiler_rotation_offset screen_width is
used to calculate the required row_inc for DISPC. x_predecim and y_predecim are
also used to calculate row_inc and pix_inc thereby adding predecimation support
for TILER.
Signed-off-by: Chandrabhanu Mahapatra <cmahapatra@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
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