The output drivers need some operations from the overlay managers, like
enable and set_timings. These will affect the dispc registers, and need
to be synchronized with the composition-side changes with overlays and
overlay managers.

We want to handle these calls in the apply.c in the compatibility mode,
but when in non-compat mode, the calls need to be handled by some other
component (e.g. omapdrm).

To make this possible, this patch creates a set of function pointers in
a dss_mgr_ops struct, that is used to redirect the calls into the
correct destination.

The non-compat users can install their mgr ops with
dss_install_mgr_ops() function.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

We currently attach an output to a dssdev in the initialization code for
dssdevices in display.c. This works, but doesn't quite make sense: an
output entity represents (surprisingly) an output of DSS, which is
managed by an output driver. The output driver also handles adding new
dssdev's for that particular output.

It makes more sense to make the output-dssdev connection in the output
driver. This is also in line with common display framework.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Links between DSS entities are made in dss_init_connections() when a panel
device is registered, and are removed in dss_uninit_connections() when the
device is unregistered. Modify these functions to incorporate the addition of
outputs.

The fields in omap_dss_device struct gives information on which output and
manager to connect to. The desired manager and output pointers are retrieved and
prepared to form the desired links. The output is linked to the device, and then
the manager to the output.

A helper function omapdss_get_output_from_device() is created to retrieve the
output from the display by checking it's type, and the module id in case of DSI.
Signed-off-by: NArchit Taneja <archit@ti.com>

An output entity represented by the struct omap_dss_output connects to a
omap_dss_device entity. Add functions to set or unset an output's device. This
is similar to how managers and devices were connected previously. An output can
connect to a device without being connected to a manager. However, the output
needs to eventually connect to a manager so that the connected panel can be
enabled.

Keep the omap_overlay_manager pointer in omap_dss_device for now to prevent
breaking things. This will be removed later when outputs are supported
completely.
Signed-off-by: NArchit Taneja <archit@ti.com>

The current OMAPDSS design contains 3 software entities: Overlays, Managers and
Devices. These map to pipelines, overlay managers and the panels respectively in
hardware. One or more overlays connect to a manager to represent a composition,
the manager connects to a device(generally a display) to display the content.

The part of DSS hardware which isn't represented by any of the above entities
are interfaces/outputs that connect to an overlay manager, i.e blocks like DSI,
HDMI, VENC and so on. Currently, an overlay manager directly connects to the
display, and the output to which it is actually connected is ignored. The panel
driver of the display is responsible of calling output specific functions to
configure the output.

Adding outputs as a new software entity gives us the following benefits:

- Have exact information on the possible connections between managers and
  outputs: A manager can't connect to each and every output, there only limited
  hardware links between a manager's video port and some of the outputs.

- Remove hacks related to connecting managers and devices: Currently, default
  links between managers and devices are set in a not so clean way. Matching is
  done via comparing the device type, and the display types supported by the
  manager. This isn't sufficient to establish all the possible links between
  managers, outputs and devices in hardware.

- Make panel drivers more generic: The DSS panel drivers currently call
  interface/output specific functions to configure the hardware IP. When making
  these calls, the driver isn't actually aware of the underlying output. The
  output driver extracts information from the panel's omap_dss_device pointer
  to figure out which interface it is connected to, and then configures the
  corresponding output block. An example of this is when a DSI panel calls
  dsi functions, the dsi driver figures out whether the panel is connected
  to DSI1 or DSI2. This isn't correct, and having output as entities will
  give the panel driver the exact information on which output to configure.
  Having outputs also gives the opportunity to make panel drivers generic
  across different platforms/SoCs, this is achieved as omap specific output
  calls can be replaced by ops of a particular output type.

- Have more complex connections between managers, outputs and devices: OMAPDSS
  currently doesn't support use cases like 2 outputs connect to a single
  device. This can be achieved by extending properties of outputs to connect to
  more managers or devices.

- Represent writeback as an output: The writeback pipeline fits well in OMAPDSS
  as compared to overlays, managers or devices.

Add a new struct to represent outputs. An output struct holds pointers to the
manager and device structs to which it is connected. Add functions which can
register/unregister an output, or look for one. Create an enum which represent
each output instance.
Signed-off-by: NArchit Taneja <archit@ti.com>

Resetting DISPC when a DISPC output is enabled causes the DSS to go into an
inconsistent state. Thus if the bootloader has enabled a display, the hwmod code
cannot reset the DISPC module just like that, but the outputs need to be
disabled first.

Add function dispc_disable_outputs() which disables all active overlay manager
and ensure all frame transfers are completed.

Modify omap_dss_reset() to call this function and clear DSS_CONTROL,
DSS_SDI_CONTROL and DSS_PLL_CONTROL so that DSS is in a clean state when the
DSS2 driver starts.

This resolves the hang issue(caused by a L3 error during boot) seen on the
beagle board C3, which has a factory bootloader that enables display. The issue
is resolved with this patch.

Thanks to Tomi and Sricharan for some additional testing.
Acked-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Tested-by: NR, Sricharan <r.sricharan@ti.com>
Signed-off-by: NArchit Taneja <archit@ti.com>
[paul@pwsan.com: restructured code, removed omap_{read,write}l(), removed
 cpu_is_omap*() calls and converted to dev_attr]
Signed-off-by: NPaul Walmsley <paul@pwsan.com>