dma: add channel request API that supports deferred probe

dma_request_slave_channel() simply returns NULL whenever DMA channel
lookup fails. Lookup could fail for two distinct reasons:

a) No DMA specification exists for the channel name.
   This includes situations where no DMA specifications exist at all, or
   other general lookup problems.

b) A DMA specification does exist, yet the driver for that channel is not
   yet registered.

Case (b) should trigger deferred probe in client drivers. However, since
they have no way to differentiate the two situations, it cannot.

Implement new function dma_request_slave_channel_reason(), which performs
identically to dma_request_slave_channel(), except that it returns an
error-pointer rather than NULL, which allows callers to detect when
deferred probe should occur.

Eventually, all drivers should be converted to this new API, the old API
removed, and the new API renamed to the more desirable name. This patch
doesn't convert the existing API and all drivers in one go, since some
drivers call dma_request_slave_channel() then dma_request_channel() if
that fails. That would require either modifying dma_request_channel() in
the same way, or adding extra error-handling code to all affected
drivers, and there are close to 100 drivers using the other API, rather
than just the 15-20 or so that use dma_request_slave_channel(), which
might be tenable in a single patch.

acpi_dma_request_slave_chan_by_name() doesn't currently implement
deferred probe. It should, but this will be addressed later.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: dmaengine@vger.kernel.org
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
v3:
* s/_or_err/_reason/ in the new API name.
* Simplify changes to of_dma_request_slave_channel() so that the new
  "bool defer" parameter is not needed.
* Revert changes to acpi-dma.c and handle the return value conversion
  in dma_request_slave_channel_reason() instead.
* Mention that acpi_dma_request_slave_chan_by_name() should implement
  deferred probe, but that will happen later.
v2:
* include <linux/err.h> in <linux/dmaengine.h>
* Return -ENODATA if slave_id or chan_id out-of-range.
* Return an error-pointer not NULL if we can't find a matching DMA
  controller or translate the channel.

This patch is a dependency for:
* A series that reworks many of the Tegra drivers.
* A series that enhances ASoC's dmaengine code to support deferred probe.

As such, it needs to go into a topic branch on its own, based directly
on 3.13-rc1. If the DMA maintainers ack the patches I'm happy to create
this topic branch myself and send a pull request to the DMA tree. Or the
patches can be applied to a topic branch by the DMA maintainers and I
will merge their topic branch into the Tegra rework branch that I
mentioned.
dma: add common of_dma_slave_xlate()

mmp_pdma.c implements a custom of_xlate() function that is 95% identical
to what Tegra will need. Create a function to implement the common part,
so everyone doesn't just cut/paste the implementation.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
This patch is a dependency for a series that reworks many of the Tegra
drivers.

As such, it needs to go into a topic branch on its own, based directly
on 3.13-rc1. If the DMA maintainers ack the patches I'm happy to create
this topic branch myself and send a pull request to the DMA tree. Or the
patches can be applied to a topic branch by the DMA maintainers and I
will merge their topic branch into the Tegra rework branch that I
mentioned.

Note that this patch is independant from the "dma: add channel request
API that supports deferred probe" which I just sent, so it could
(should?) be a different topic branch.
dma: mmp_pdma: use of_dma_slave_xlate()

Use the new common of_dma_slave_xlate() function to avoid duplicating
most of the of_xlate() implementation.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
This patch depends on the previous "dma: add common
of_dma_slave_xlate()", but isn't a dependency for other branches, so
can be applied just to the regular drivers/dma tree once the dependency
is merged in.
ASoC: dmaengine: support deferred probe for DMA channels

Enhance dmaengine_pcm_request_chan_of() to support deferred probe for
DMA channels, by using the new dma_request_slave_channel_or_err() API.
This prevents snd_dmaengine_pcm_register() from succeeding without
acquiring DMA channels due to the relevant DMA controller not yet being
registered.

Cc: treding@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: alsa-devel@alsa-project.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Mark Brown <broonie@linaro.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
---
v2: Call dmaengine_pcm_release_chan() if dmaengine_pcm_request_chan_of()
    fails, to clean up any partial allocations.

This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
ASoC: dmaengine: add custom DMA config to snd_dmaengine_pcm_config

Add fields to struct snd_dmaengine_pcm_config to allow custom:

- DMA channel names.

  This is useful when the default "tx" and "rx" channel names don't
  apply, for example if a HW module supports multiple channels, each
  having different DMA channel names. This is the case with the FIFOs
  in Tegra's AHUB. This new facility can replace
  SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME.

- DMA device

  This allows requesting DMA channels for a device other than the device
  which is registering the "PCM" driver. This is quite unusual, but is
  currently useful on Tegra. In much HW, and in Tegra20, each DAI HW
  module contains its own FIFOs which DMA writes to. However, in Tegra30,
  the DMA FIFOs were split out AHUB HW module, which then routes the data
  through a cross-bar, and into the DAI HW modules. However, the current
  ASoC driver structure does not expose this detail, and acts as if the
  FIFOs are still part of the DAI HW modules. Consequently, the "PCM"
  driver is registered with the DAI HW module, yet the DMA channels must
  be looked up in the AHUB HW module's device tree node. This new config
  field allows that to happen. Eventually, the Tegra drivers will be
  reworked to fully expose the AHUB, and this config field can be
  removed.

Cc: treding@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: alsa-devel@alsa-project.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Mark Brown <broonie@linaro.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
---
v2:
* dev_warn() in dmaengine_pcm_request_chan_of() if config->dev is set;
  drivers generally shouldn't need this feature, and should be re-
  structured if they do.

This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
ARM: tegra: add missing clock documentation to DT bindings

Many of the Tegra DT binding documents say nothing about the clocks or
clock-names properties, yet those are present and required in DT files.
This patch simply updates the documentation file to match the implicit
definition of the binding, based on real-world DT content.

All Tegra bindings that mention clocks are updated to have consistent
wording and formatting of the clock-related properties.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: devicetree@vger.kernel.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-By: Terje Bergstrom <tbergstrom@nvidia.com>
---
v2:
* Removed duplicate documentation for "clocks" property in some nodes.
* Modified dsi example node to match binding requirements.
---
Series cover letter:

This series implements a common reset framework driver for Tegra, and
updates all relevant Tegra drivers to use it. It also removes the custom
DMA bindings and replaced them with the standard DMA DT bindings.

Historically, the Tegra clock driver has exported a custom API for module
reset. This series removes that API, and transitions DT and drivers to
the new reset framework.

The custom API used a "struct clk" to identify which module to reset, and
consequently some DT bindings and drivers required clocks to be provided
where they really needed just a reset identifier instead. Due to this
known deficiency, I have always considered most Tegra bindings to be
unstable. This series removes this excuse for instability, although I
still consider some Tegra bindings unstable due to the need to convert to
the common DMA bindings.

Historically, Tegra DMA channels have been represented in DT using a
custom nvidia,dma-request-selector property. Now that standard DMA DT
bindings exist, convert all Tegra bindings, DTs, and drivers to use the
standard instead.

This series makes a DT-ABI-incompatible change to:
- Require reset specifiers in DT where relevant.
- Require standard DMA specifiers.
- Remove clock specifiers from DT where they were only needed for reset.
- Remove legacy DMA specifier properties.

I anticipate merging this whole series into the Tegra and arm-soc trees
as its own branch, due to internal dependencies. This branch will be
stable and can then be merged into any other subsystem trees should any
conflicts arise.

Cc: ac100@lists.launchpad.net
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: alsa-devel@alsa-project.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: devel@driverdev.osuosl.org
Cc: devicetree@vger.kernel.org
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: dri-devel@lists.freedesktop.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Julian Andres Klode <jak@jak-linux.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-i2c@vger.kernel.org
Cc: linux-input@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Cc: linux-spi@vger.kernel.org
Cc: linux-tegra@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: Marc Dietrich <marvin24@gmx.de>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: pdeschrijver@nvidia.com
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Terje Bergström <tbergstrom@nvidia.com>
Cc: treding@nvidia.com
Cc: Wolfram Sang <wsa@the-dreams.de>
ARM: tegra: document reset properties in DT bindings

Update all the Tegra DT bindings to require resets/reset-names properties
where the HW module has reset inputs. Remove any entries from clocks or
clock-names that were only required to identify reset inputs, rather than
referring to real clocks.

This is a DT-ABI-incompatible change. It is the first of two changes
required for me to consider the Tegra DT bindings as stable, the other
being conversion to the common DMA DT bindings.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: devicetree@vger.kernel.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-By: Terje Bergstrom <tbergstrom@nvidia.com>
ARM: tegra: document use of standard DMA DT bindings

Update all the Tegra DT bindings to require the standard dmas/dma-names
properties rather than non-standard nvidia,dma-request-selector property.

This is a DT-ABI-incompatible change. It is the second of two changes
required for me to consider the Tegra DT bindings as stable, the other
being the previous conversion to the common reset bindings.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: devicetree@vger.kernel.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
v3: s/iommu/dma/ in the binding doc.
v2: Document the #iommu-cells property in the DMA controller binding.
ARM: tegra: update DT files to add reset properties

An earlier patch updated the Tegra DT bindings to require resets and
reset-names properties to be filled in. This patch updates the DT files
to include those properties.

Note that any legacy clocks and clock-names entries that are replaced by
reset properties are not yet removed; the drivers must be updated to use
the new resets and reset-names properties first.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: devicetree@vger.kernel.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
ARM: tegra: update DT files to add DMA properties

This patch switches the Tegra DT files to use the standard DMA DT bindings
rather than custom properties. Note that the legacy properties are not yet
removed; the drivers must be updated to use the new properties first.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: devicetree@vger.kernel.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
ARM: tegra: select the reset framework

The Tegra clock driver is built unconditionally when Tegra support is
enabled. In order to avoid having to ifdef the forthcoming reset driver
implementation, have ARCH_TEGRA select RESET_CONTROLLER.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
clk: tegra: implement a reset driver

The Tegra CAR module implements both a clock and reset controller. So
far, the driver exposes the clock feature via the common clock API and
the reset feature using a custom API. This patch adds an implementation
of the common reset framework API (include/linux/reset*.h). The legacy
reset implementation will be removed once all drivers have been
converted.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
pci: tegra: use reset framework

Tegra's clock driver now provides an implementation of the common
reset API (include/linux/reset.h). Use this instead of the old Tegra-
specific API; that will soon be removed.

The old Tegra-specific API used a struct clock to represent the module
to reset. Some of the clocks retrieved during probe() were only used for
reset purposes, and indeed aren't even true clocks. So, there's no need
to get() them any more.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
drm/tegra: use reset framework

Tegra's clock driver now provides an implementation of the common
reset API (include/linux/reset.h). Use this instead of the old Tegra-
specific API; that will soon be removed.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-By: Terje Bergstrom <tbergstrom@nvidia.com>
---
This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
ARM: tegra: pass reset to tegra_powergate_sequence_power_up()

Tegra's clock driver now provides an implementation of the common
reset API (include/linux/reset.h). Use this instead of the old Tegra-
specific API; that will soon be removed.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-pci@vger.kernel.org
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-By: Terje Bergstrom <tbergstrom@nvidia.com>
---
This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
dma: tegra: use reset framework

Tegra's clock driver now provides an implementation of the common
reset API (include/linux/reset.h). Use this instead of the old Tegra-
specific API; that will soon be removed.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
dma: tegra: register as an OF DMA controller

Call of_dma_controller_register() so that DMA clients can look up the
Tegra DMA controller using standard APIs. This requires the OF filter
function to save off the DMA slave ID, and for tegra_dma_slave_config()
not to over-write this information; once DMA client drivers are converted
to dma_request_slave_channel() and DT-based lookups, they won't set this
field of struct dma_slave_config anymore.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
v2: Use of_dma_slave_xlate() rather than of_dma_simple_xlate(), as
    suggested by Arnd Bergmann.

This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
ASoC: tegra: use reset framework

Tegra's clock driver now provides an implementation of the common
reset API (include/linux/reset.h). Use this instead of the old Tegra-
specific API; that will soon be removed.

This change also renames "clock"/"clk" to "modules"/"mod" in symbols
related to entries in configlink_clocks[], since:
- We don't care about clock handles any more, but rather reset handles,
  so the old name isn't applicable.
- It really is a list of modules on the bus, about which we currently
  only care about reset handles.
If we start caring about any other aspect of the modules in the future,
we won't have to rename all these symbols again.

Note: The addition of "depends COMMON_CLOCK" is something that was missing
before, not a new requirement.

Cc: treding@nvidia.com
Cc: pdeschrijver@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: alsa-devel@alsa-project.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
ASoC: tegra: call pm_runtime APIs around register accesses

Call pm_runtime_get_sync() before all register accesses; the HW requires
clocks to be running when accessing registers.

This hasn't been needed to date, since all register IO was performed
while playback was active, and hence the ASoC core had already called
pm_runtime_get(). However, an imminent future commit will allocate and
set up the FIFOs and routing during probe(), when that "protection"
won't be in place.

Cc: treding@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: alsa-devel@alsa-project.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Mark Brown <broonie@linaro.org>
---
This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
ASoC: tegra: allocate AHUB FIFO during probe() not startup()

Teh Tegra30 I2S driver currently allocates DMA FIFOs from the AHUB only
when an audio stream starts playback. This is theoretically nice for
resource sharing, but makes no practical difference for any configuration
the drivers currently support. However, this deferral prevents conversion
to the standard DMA DT bindings, since conversion requires knowledge of
the specific DMA channel to be allocated, which in turn depends on which
specific FIFO was allocated.

For this reason, move the FIFO allocate into probe() to allow later
conversion to the standard DMA DT bindings.

Cc: treding@nvidia.com
Cc: linux-tegra@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: alsa-devel@alsa-project.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Mark Brown <broonie@linaro.org>
---
This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.