dmaengine: omap-dma: consolidate writes to DMA registers

There's no need to keep writing registers which don't change value in
omap_dma_start_sg().  Move this into omap_dma_start_desc() and merge
the register updates together.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: control start/stop directly

Program the non-cyclic mode DMA start/stop directly, rather than via
arch/arm/plat-omap/dma.c.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: move reading of dma position to omap-dma.c

Read the current DMA position from the hardware directly rather than via
arch/arm/plat-omap/dma.c.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: consolidate setup of CSDP

Consolidate the setup of the channel source destination parameters
register.  This way, we calculate the required CSDP value when we setup
a transfer descriptor, and only write it to the device registers once
when we start the descriptor.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: consolidate setup of CCR

Consolidate the setup of the channel control register.  Prepare the
basic value in the preparation of the DMA descriptor, and write it into
the register upon descriptor execution.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: provide register definitions

Provide our own set of more complete register definitions; this allows
us to get rid of the meaningless 1 << n constants scattered throughout
this code.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: move CCR buffering disable errata out of the fast path

Since we record the CCR register in the dma transaction, we can move the
processing of the iframe buffering errata out of the omap_dma_start().
Move it to the preparation functions.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: consolidate clearing channel status register

Consolidate clearing of the channel status register, rather than open
coding the same functionality in two places.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
drm: Add support for two-ended allocation, v3

Clients like i915 need to segregate cache domains within the GTT which
can lead to small amounts of fragmentation. By allocating the uncached
buffers from the bottom and the cacheable buffers from the top, we can
reduce the amount of wasted space and also optimize allocation of the
mappable portion of the GTT to only those buffers that require CPU
access through the GTT.

For other drivers, allocating small bos from one end and large ones
from the other helps improve the quality of fragmentation.

Based on drm_mm work by Chris Wilson.

v3: Changed to use a TTM placement flag
v2: Updated kerneldoc

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Christian König <deathsimple@vodafone.de>
Signed-off-by: Lauri Kasanen <cand@gmx.com>
Signed-off-by: David Airlie <airlied@redhat.com>
drm/radeon: Use two-ended allocation by size, v2

This decreases eviction by up to 20%, by improving the fragmentation
quality. No harm in normal cases that fit VRAM fully (PTS gaming suite).

In some cases, even the VRAM-fitting cases improved slightly (openarena, urban terror).

512kb was measured as the most optimal threshold for 3d workloads common to radeon.
Other drivers may need different thresholds according to their workloads.

v2: Nicer formatting
Signed-off-by: Lauri Kasanen <cand@gmx.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
dmaengine: omap-dma: improve efficiency loading C.SA/C.EI/C.FI registers

The only thing which changes is which registers are written, so put this
in local variables instead.  This results in smaller code.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: move clnk_ctrl setting to preparation functions

Move the clnk_ctrl setup to the preparation functions, saving its
value in the omap_desc.  This only needs to be set once per descriptor,
not for each segment, so set it in omap_dma_start_desc() rather than
omap_dma_start().

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: move barrier to omap_dma_start_desc()

We don't need to issue a barrier for every segment of a DMA transfer;
doing this just once per descriptor will do.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: use cached CCR value when enabling DMA

We don't need to read-modify-write the CCR register; we already know
what value it should contain at this point.  Use the cached CCR value
when setting the enable bit.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: provide register read/write functions

Provide a pair of channel register accessors, and a pair of global
accessors for non-channel specific registers.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dmaengine: omap-dma: cleanup errata 3.3 handling

Provide a function to read the CSAC/CDAC register, working around the
OMAP 3.2/3.3 erratum (which requires two reads of the register if the
first returned zero.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: omap: remove references to disable_irq_lch

The disable_irq_lch method is never actually used, so there's not much
point it existing; remove it.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: omap: remove almost-const variables

dma_stride and dma_common_ch_start are only ever initialised to one
known value at initialisation, and are private to each of these files.
There's no point these being variables at all.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: omap: clean up DMA register accesses

We can do much better with this by using a structure to describe each
register, rather than code.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: omap: dma: get rid of errata global

There's no need for this to be a global variable; move it into the
errata configuration function instead.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>