gpu: host1x: Do not setup DMA for virtual devices

The host1x devices are virtual compound devices and do not perform DMA
accesses themselves, so they do not need to be set up for DMA.

Ideally we would also not need to set up DMA masks for the virtual
devices, but we currently still need those for legacy support on old
hardware.

Tested-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240314154943.2487549-1-thierry.reding@gmail.com

gpu: host1x: bus: make host1x_bus_type const

Since commit d492cc2573a0 ("driver core: device.h: make struct
bus_type a const *"), the driver core can properly handle constant
struct bus_type, move the host1x_bus_type variable to be a constant
structure as well, placing it into read-only memory which can not be
modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240213-bus_cleanup-host1x-v1-1-54ec51b5d14f@marliere.net

gpu: host1x: Stop open-coding of_device_uevent()

There is apparently no reasons to open-code of_device_uevent() besides:
- The helper receives a struct device while we want to use the of_node
member of the struct device *parent*.
- of_device_uevent() could not be called by modules because of a missing
EXPORT_SYMBOL*().

In practice, the former point is not very constraining, just calling
of_device_uevent(dev->parent, ...) would have made the trick.

The latter point is more an observation rather than a real blocking
point because nothing prevented of_uevent() (called by the inline
function of_device_uevent()) to be exported to modules. In practice,
this helper is now exported, so nothing prevent us from using
of_device_uevent() anymore.

Let's use the core helper directly instead of open-coding it.

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Mikko Perttunen <mperttunen@nvidia.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230622213214.3586530-3-miquel.raynal@bootlin.com

gpu: host1x: Make host1x_client_unregister() return void

This function returned zero unconditionally. Make it return no value and
simplify all callers accordingly.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Thierry Reding <treding@nvidia.com>

driver core: make struct bus_type.uevent() take a const *

The uevent() callback in struct bus_type should not be modifying the
device that is passed into it, so mark it as a const * and propagate the
function signature changes out into all relevant subsystems that use
this callback.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230111113018.459199-16-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

gpu: host1x: Add missing DMA API include

Host1x seems to be relying on picking up dma-mapping.h transitively from
iova.h, which has no reason to include it in the first place. Fix the
former issue before we totally break things by fixing the latter one.

CC: Thierry Reding <thierry.reding@gmail.com>
CC: Mikko Perttunen <mperttunen@nvidia.com>
CC: dri-devel@lists.freedesktop.org
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Drop excess kernel-doc entry @key

Fix kernel-doc warning in host1x:

../drivers/gpu/host1x/bus.c:774: warning: Excess function parameter 'key' description in '__host1x_client_register'

Fixes: 0cfe5a6e758f ("gpu: host1x: Split up client initalization and registration")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-tegra@vger.kernel.org
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drm/tegra: Implement buffer object cache

This cache is used to avoid mapping and unmapping buffer objects
unnecessarily. Mappings are cached per client and stay hot until
the buffer object is destroyed.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Split up client initalization and registration

In some cases we may need to initialize the host1x client first before
registering it. This commit adds a new helper that will do nothing but
the initialization of the data structure.

At the same time, the initialization is removed from the registration
function. Note, however, that for simplicity we explicitly initialize
the client when the host1x_client_register() function is called, as
opposed to the low-level __host1x_client_register() function. This
allows existing callers to remain unchanged.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Add early init and late exit callbacks

These callbacks can be used by client drivers to run code during early
init and during late exit. Early init callbacks are run prior to the
regular init callbacks while late exit callbacks run after the regular
exit callbacks.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Use different lock classes for each client

To avoid false lockdep warnings, give each client lock a different
lock class, passed from the initialization site by macro.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu/host1x: bus: Add missing description for 'driver'

Fixes the following W=1 kernel build warning(s):

drivers/gpu/host1x/bus.c:40: warning: Function parameter or member 'driver' not described in 'host1x_subdev_add'

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201105144517.1826692-2-lee.jones@linaro.org

gpu: host1x: Detach driver on unregister

Currently when a host1x device driver is unregistered, it is not
detached from the host1x controller, which means that the device
will stay around and when the driver is registered again, it may
bind to the old, stale device rather than the new one that was
created from scratch upon driver registration. This in turn can
cause various weird crashes within the driver core because it is
confronted with a device that was already deleted.

Fix this by detaching the driver from the host1x controller when
it is unregistered. This ensures that the deleted device also is
no longer present in the device list that drivers will bind to.

Reported-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Tested-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drm/tegra: Do not implement runtime PM

The Tegra DRM driver heavily relies on the implementations for runtime
suspend/resume to be called at specific times. Unfortunately, there are
some cases where that doesn't work. One example is if the user disables
runtime PM for a given subdevice. Another example is that the PM core
acquires a reference to runtime PM during system sleep, effectively
preventing devices from going into low power modes. This is intentional
to avoid nasty race conditions, but it also causes system sleep to not
function properly on all Tegra systems.

Fix this by not implementing runtime PM at all. Instead, a minimal,
reference-counted suspend/resume infrastructure is added to the host1x
bus. This has the benefit that it can be used regardless of the system
power state (or any transitions we might be in), or whether or not the
user allows runtime PM.

Atomic modesetting guarantees that these functions will end up being
called at the right point in time, so the pitfalls for the more generic
runtime PM do not apply here.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Rename "parent" to "host"

Rename the host1x clients' parent to "host" because that more closely
describes what it is. The parent can be confused with the parent device
in terms of the device hierarchy. Subsequent patches will add a new
member that refers to the parent in that hierarchy.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Do not limit DMA segment size

host1x nor any its clients have any limitations on the DMA segment size,
so don't pretend that they do.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Do not link logical devices to DT nodes

Logical devices created by the host1x bus infrastructure don't need to
be associated with a device tree node. Doing so will cause the driver
core to attempt to hook up IOMMU operations and fail because it is not
a real device.

However, for backwards-compatibility, we need to provide various OF_*
uevent variables that were previously provided by of_device_uevent() and
which are parsed by libdrm in userspace when querying the available
devices. Do this by implementing a uevent callback for the host1x bus.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Increase maximum DMA segment size

Recent versions of the DMA API debug code have started to warn about
violations of the maximum DMA segment size. This is because the segment
size defaults to 64 KiB, which can easily be exceeded in large buffer
allocations such as used in DRM/KMS for framebuffers.

Technically the Tegra SMMU and ARM SMMU don't have a maximum segment
size (they map individual pages irrespective of whether they are
contiguous or not), so the choice of 4 MiB is a bit arbitrary here. The
maximum segment size is a 32-bit unsigned integer, though, so we can't
set it to the correct maximum size, which would be the size of the
aperture.

Signed-off-by: Thierry Reding <treding@nvidia.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
version 2 as published by the free software foundation this program
is distributed in the hope it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 228 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171438.107155473@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

gpu: host1x: Represent host1x bus devices in debugfs

This new debugfs file represents the state of host1x bus devices,
specifying the list of subdevices and marking which ones have
successfully registered.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Remove spurious tab

All other assignments have a single space around the = sign, so remove
the spurious tab for consistency.

Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers: remove force dma flag from buses

With each bus implementing its own DMA configuration callback, there is no
need for bus to explicitly set the force_dma flag. Modify the
of_dma_configure function to accept an input parameter which specifies if
implicit DMA configuration is required when it is not described by the
firmware.

Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> # PCI parts
Reviewed-by: Rob Herring <robh@kernel.org>
[hch: tweaked the changelog a bit]
Signed-off-by: Christoph Hellwig <hch@lst.de>

dma-mapping: move dma configuration to bus infrastructure

ACPI/OF support for configuration of DMA is a bus specific aspect, and
thus should be configured by the bus. Introduces a 'dma_configure' bus
method so that busses can control their DMA capabilities.

Also update the PCI, Platform, ACPI and host1x buses to use the new
method.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> # PCI parts
Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[hch: simplified host1x_dma_configure based on a comment from Thierry,
rewrote changelog]
Signed-off-by: Christoph Hellwig <hch@lst.de>

gpu: host1x: Cleanup on initialization failure

When an error happens during the initialization of one of the sub-
devices, make sure to properly cleanup all sub-devices that have been
initialized up to that point.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Call of_dma_configure() after setting bus

of_dma_configure() now checks the device's bus before configuring it, so
we need to set the device's bus before calling.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers: flag buses which demand DMA configuration

We do not want the common dma_configure() pathway to apply
indiscriminately to all devices, since there are plenty of buses which
do not have DMA capability, and if their child devices were used for
DMA API calls it would only be indicative of a driver bug. However,
there are a number of buses for which DMA is implicitly expected even
when not described by firmware - those we whitelist with an automatic
opt-in to dma_configure(), assuming that the DMA address space and the
physical address space are equivalent if not otherwise specified.

Commit 723288836628 ("of: restrict DMA configuration") introduced a
short-term fix by comparing explicit bus types, but this approach is far
from pretty, doesn't scale well, and fails to cope at all with bus
drivers which may be built as modules, like host1x. Let's refine things
by making that opt-in a property of the bus type, which neatly addresses
those problems and lets the decision of whether firmware description of
DMA capability should be optional or mandatory stay internal to the bus
drivers themselves.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

gpu: host1x: Support sub-devices recursively

The display architecture in Tegra186 changes slightly compared to
earlier Tegra generations, which requires that we recursively scan
host1x sub-devices from device tree.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu/host1x: Remove excess parameter in host1x_subdev_add docs

Fixes the following warning when building docs:
../drivers/gpu/host1x/bus.c:50: warning: Excess function parameter 'driver' description in 'host1x_subdev_add'

Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170720174746.29100-4-seanpaul@chromium.org

gpu: host1x: Flesh out kerneldoc

Improve kerneldoc for the public parts of the host1x infrastructure in
preparation for adding driver-specific part to the GPU documentation.

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Fix host1x driver shutdown

Shutting down a host1x device currently crashes if the device has failed
to probe. The root cause is that the host1x shutdown is implemented as a
struct bus_type callback, but in turn relies on the driver bound to the
device. On failure to probe, no driver will be bound and cause the code
to crash.

Fix this by moving the ->probe(), ->remove() and ->shutdown() callbacks
to the driver rather than the bus.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Set OF node for new host1x devices

We use the OF node of the host1x device's parent because it's the
closest we have.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: bus: Add missing of_node_put()

for_each_child_of_node() performs an of_node_get() on each iteration, so
to break out of the loop an of_node_put() is required.

Found using Coccinelle. The semantic patch used for this is as follows:

// <smpl>
@@
expression e;
local idexpression n;
@@

for_each_child_of_node(..., n) {
... when != of_node_put(n)
when != e = n
(
return n;
|
+ of_node_put(n);
? return ...;
)
...
}
// </smpl>

Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Set DMA ops on device creation

Currently host1x-instanciated devices have their dma_ops left to NULL,
which makes any DMA operation (like buffer import) on ARM64 fallback
to the dummy_dma_ops and fail with an error.

This patch calls of_dma_configure() with the host1x node when creating
such a device, so the proper DMA operations are set.

Suggested-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Remove core driver on unregister

When unregistering a host1x driver, make sure to unregister the core
driver as well to prevent it from sticking around and oppose reloading
of the driver.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Provide a proper struct bus_type

Previously the struct bus_type exported by the host1x infrastructure was
only a very basic skeleton. Turn that implementation into a more full-
fledged bus to support proper probe ordering and power management.

Note that the bus infrastructure needs to be available before any of the
drivers can be registered. This is automatically ensured if all drivers
are built as loadable modules (via symbol dependencies). If all drivers
are built-in there are no such guarantees and the link order determines
the initcall ordering. Adjust drivers/gpu/Makefile to make sure that the
host1x bus infrastructure is initialized prior to any of its users (only
drm/tegra currently).

v2: Fix building host1x and tegra-drm as modules
Reported-by: Dave Airlie <airlied@gmail.com>

Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Mark Zhang <markz@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Factor out __host1x_device_del()

This function is needed in several places, so factor it out.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Call host1x_device_add() under lock

Instead of locking within host1x_device_add(), call it under the lock to
make the locking more consistent.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Call ->remove() only when a device is bound

When a driver's ->probe() function fails, the host1x bus must not call
its ->remove() function because the driver will already have cleaned up
in the error handling path in ->probe().

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Rename internal functions for clarity

The internal host1x_{,un}register_client() functions can potentially be
confused with public the host1x_client_{,un}register() functions.

Rename them to host1x_{add,del}_client() to remove some of the possible
confusion.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Export public API

Make the public API symbols visible so that depending drivers can be
built as a module.

Signed-off-by: Thierry Reding <treding@nvidia.com>

gpu: host1x: Fix a few sparse warnings

Include the bus.h header, so that various function declarations are
visible in the source file that implements those functions. This keeps
sparse from suggesting that they should be made static.

Make the host1x_bus_type variable static since it isn't used globally.

Finally replace the slightly unsafe dev_set_name(dev, name) by the more
secure dev_set_name(dev, "%s", name).

Signed-off-by: Thierry Reding <treding@nvidia.com>

drm/tegra: Move subdevice infrastructure to host1x

The Tegra DRM driver currently uses some infrastructure to defer the DRM
core initialization until all required devices have registered. The same
infrastructure can potentially be used by any other driver that requires
more than a single sub-device of the host1x module.

Make the infrastructure more generic and keep only the DRM specific code
in the DRM part of the driver. Eventually this will make it easy to move
the DRM driver part back to the DRM subsystem.

Signed-off-by: Thierry Reding <treding@nvidia.com>