driver core: Constify API device_find_child() and adapt for various usages

Constify the following API:
struct device *device_find_child(struct device *dev, void *data,
int (*match)(struct device *

driver core: Constify API device_find_child() and adapt for various usages

Constify the following API:
struct device *device_find_child(struct device *dev, void *data,
int (*match)(struct device *dev, void *data));
To :
struct device *device_find_child(struct device *dev, const void *data,
device_match_t match);
typedef int (*device_match_t)(struct device *dev, const void *data);
with the following reasons:

- Protect caller's match data @*data which is for comparison and lookup
and the API does not actually need to modify @*data.

- Make the API's parameters (@match)() and @data have the same type as
all of other device finding APIs (bus|class|driver)_find_device().

- All kinds of existing device match functions can be directly taken
as the API's argument, they were exported by driver core.

Constify the API and adapt for various existing usages.

BTW, various subsystem changes are squashed into this commit to meet
'git bisect' requirement, and this commit has the minimal and simplest
changes to complement squashing shortcoming, and that may bring extra
code improvement.

Reviewed-by: Alison Schofield <[email protected]>
Reviewed-by: Takashi Sakamoto <[email protected]>
Acked-by: Uwe Kleine-König <[email protected]> # for drivers/pwm
Signed-off-by: Zijun Hu <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>
Reviewed-by: Mathieu Poirier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: have match() callback in struct bus_type take a const *

In the match() callback, the struct device_driver * should not be
changed, so change the function callback to be a const *. This

driver core: have match() callback in struct bus_type take a const *

In the match() callback, the struct device_driver * should not be
changed, so change the function callback to be a const *. This is one
step of many towards making the driver core safe to have struct
device_driver in read-only memory.

Because the match() callback is in all busses, all busses are modified
to handle this properly. This does entail switching some container_of()
calls to container_of_const() to properly handle the constant *.

For some busses, like PCI and USB and HV, the const * is cast away in
the match callback as those busses do want to modify those structures at
this point in time (they have a local lock in the driver structure.)
That will have to be changed in the future if they wish to have their
struct device * in read-only-memory.

Cc: Rafael J. Wysocki <[email protected]>
Reviewed-by: Alex Elder <[email protected]>
Acked-by: Sumit Garg <[email protected]>
Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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rpmsg: core: Make rpmsg_class constant

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so m

rpmsg: core: Make rpmsg_class constant

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the rpmsg_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <[email protected]>
Suggested-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Ricardo B. Marliere <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mathieu Poirier <[email protected]>

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rpmsg: core: Make rpmsg_bus const

Now that the driver core can properly handle constant struct bus_type,
move the rpmsg_bus variable to be a constant structure as well,
placing it into read-only mem

rpmsg: core: Make rpmsg_bus const

Now that the driver core can properly handle constant struct bus_type,
move the rpmsg_bus 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 <[email protected]>
Suggested-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Ricardo B. Marliere <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mathieu Poirier <[email protected]>

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rpmsg: core: Replace deprecated strncpy with strscpy

strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
inte

rpmsg: core: Replace deprecated strncpy with strscpy

strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

We expect chinfo.name to be NUL-terminated based on its usage with
strncmp():

rpmsg_core.c:
389: if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))

Moreover, NUL-padding is not required as chinfo has stack default
initialized all fields to zero:

rpmsg_core.c:
539: struct rpmsg_channel_info chinfo = {};

Considering the above, a suitable replacement is `strscpy` [2] due to
the fact that it guarantees NUL-termination on the destination buffer
without unnecessarily NUL-padding.

Also, favor the more idiomatic strscpy() usage of:
(dest, src, sizeof(dest)).

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: [email protected]
Signed-off-by: Justin Stitt <[email protected]>
Link: https://lore.kernel.org/r/20231020-strncpy-drivers-rpmsg-rpmsg_core-c-v1-1-a86b7930c1cf@google.com
Signed-off-by: Mathieu Poirier <[email protected]>

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rpmsg: core: Add signal API support

Some transports like Glink support the state notifications between
clients using flow control signals similar to serial protocol signals.
Local glink client drive

rpmsg: core: Add signal API support

Some transports like Glink support the state notifications between
clients using flow control signals similar to serial protocol signals.
Local glink client drivers can send and receive flow control status
to glink clients running on remote processors.

Add APIs to support sending and receiving of flow control status by
rpmsg clients.

Signed-off-by: Deepak Kumar Singh <[email protected]>
Signed-off-by: Sarannya S <[email protected]>
Acked-by: Arnaud Pouliquen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Andersson <[email protected]>

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driver core: class: remove module * from class_create()

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
s

driver core: class: remove module * from class_create()

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
something. So just remove it and fix up all callers of the function in
the kernel tree at the same time.

Cc: "Rafael J. Wysocki" <[email protected]>
Acked-by: Benjamin Tissoires <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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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 th

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 <[email protected]>
Acked-by: Hans de Goede <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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rpmsg: Strcpy is not safe, use strscpy_pad() instead

Replace strcpy() with strscpy_pad() for copying the rpmsg
device name in rpmsg_register_device_override().

Reported-by: kernel test robot <lkp@i

rpmsg: Strcpy is not safe, use strscpy_pad() instead

Replace strcpy() with strscpy_pad() for copying the rpmsg
device name in rpmsg_register_device_override().

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Saud Farooqui <[email protected]>
Link: https://lore.kernel.org/r/PA4P189MB14210AA95DCA3715AFA7F4A68BB59@PA4P189MB1421.EURP189.PROD.OUTLOOK.COM
Signed-off-by: Mathieu Poirier <[email protected]>

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rpmsg: Fix possible refcount leak in rpmsg_register_device_override()

rpmsg_register_device_override need to call put_device to free vch when
driver_set_override fails.

Fix this by adding a put_dev

rpmsg: Fix possible refcount leak in rpmsg_register_device_override()

rpmsg_register_device_override need to call put_device to free vch when
driver_set_override fails.

Fix this by adding a put_device() to the error path.

Fixes: bb17d110cbf2 ("rpmsg: Fix calling device_lock() on non-initialized device")
Reviewed-by: Krzysztof Kozlowski <[email protected]>
Signed-off-by: Hangyu Hua <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mathieu Poirier <[email protected]>

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rpmsg: use local 'dev' variable

'&rpdev->dev' is already cached as local variable, so use it to simplify
the code.

Signed-off-by: Krzysztof Kozlowski <[email protected]>
Link: https://

rpmsg: use local 'dev' variable

'&rpdev->dev' is already cached as local variable, so use it to simplify
the code.

Signed-off-by: Krzysztof Kozlowski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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rpmsg: Fix calling device_lock() on non-initialized device

driver_set_override() helper uses device_lock() so it should not be
called before rpmsg_register_device() (which calls device_register()).

rpmsg: Fix calling device_lock() on non-initialized device

driver_set_override() helper uses device_lock() so it should not be
called before rpmsg_register_device() (which calls device_register()).
Effect can be seen with CONFIG_DEBUG_MUTEXES:

DEBUG_LOCKS_WARN_ON(lock->magic != lock)
WARNING: CPU: 3 PID: 57 at kernel/locking/mutex.c:582 __mutex_lock+0x1ec/0x430
...
Call trace:
__mutex_lock+0x1ec/0x430
mutex_lock_nested+0x44/0x50
driver_set_override+0x124/0x150
qcom_glink_native_probe+0x30c/0x3b0
glink_rpm_probe+0x274/0x350
platform_probe+0x6c/0xe0
really_probe+0x17c/0x3d0
__driver_probe_device+0x114/0x190
driver_probe_device+0x3c/0xf0
...

Refactor the rpmsg_register_device() function to use two-step device
registering (initialization + add) and call driver_set_override() in
proper moment.

This moves the code around, so while at it also NULL-ify the
rpdev->driver_override in error path to be sure it won't be kfree()
second time.

Fixes: 42cd402b8fd4 ("rpmsg: Fix kfree() of static memory on setting driver_override")
Reported-by: Marek Szyprowski <[email protected]>
Signed-off-by: Krzysztof Kozlowski <[email protected]>
Tested-by: Marek Szyprowski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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rpmsg: Constify local variable in field store macro

Memory pointed by variable 'old' in field store macro is not modified,
so it can be made a pointer to const.

Signed-off-by: Krzysztof Kozlowski <

rpmsg: Constify local variable in field store macro

Memory pointed by variable 'old' in field store macro is not modified,
so it can be made a pointer to const.

Signed-off-by: Krzysztof Kozlowski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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rpmsg: Create the rpmsg class in core instead of in rpmsg char

Migrate the creation of the rpmsg class from the rpmsg_char
to the core that the class is usable by the rpmsg_char and
the future rpmsg

rpmsg: Create the rpmsg class in core instead of in rpmsg char

Migrate the creation of the rpmsg class from the rpmsg_char
to the core that the class is usable by the rpmsg_char and
the future rpmsg_ctrl module.

Suggested-by: Bjorn Andersson <[email protected]>
Signed-off-by: Arnaud Pouliquen <[email protected]>
Reviewed-by: Bjorn Andersson <[email protected]>
Signed-off-by: Bjorn Andersson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rpmsg: core: Clean up resources on announce_create failure.

During the rpmsg_dev_probe, if rpdev->ops->announce_create returns an
error, the rpmsg device and default endpoint should be freed before

rpmsg: core: Clean up resources on announce_create failure.

During the rpmsg_dev_probe, if rpdev->ops->announce_create returns an
error, the rpmsg device and default endpoint should be freed before
exiting the function.

Fixes: 5e619b48677c ("rpmsg: Split rpmsg core and virtio backend")
Suggested-by: Bjorn Andersson <[email protected]>
Signed-off-by: Arnaud Pouliquen <[email protected]>
Reviewed-by: Bjorn Andersson <[email protected]>
Cc: stable <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mathieu Poirier <[email protected]>

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rpmsg: Fix documentation return formatting

kernel documentation specification:
"The return value, if any, should be described in a dedicated section
named Return."

Signed-off-by: Arnaud Pouliquen <

rpmsg: Fix documentation return formatting

kernel documentation specification:
"The return value, if any, should be described in a dedicated section
named Return."

Signed-off-by: Arnaud Pouliquen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mathieu Poirier <[email protected]>

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rpmsg: core: add API to get MTU

Return the rpmsg buffer MTU for sending message, so rpmsg users
can split a long message in several sub rpmsg buffers.

Reviewed-by: Mathieu Poirier <mathieu.poirier@

rpmsg: core: add API to get MTU

Return the rpmsg buffer MTU for sending message, so rpmsg users
can split a long message in several sub rpmsg buffers.

Reviewed-by: Mathieu Poirier <[email protected]>
Reviewed-by: Bjorn Andersson <[email protected]>
Acked-by: Suman Anna <[email protected]>
Signed-off-by: Arnaud Pouliquen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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bus: Make remove callback return void

The driver core ignores the return value of this callback because there
is only little it can do when a device disappears.

This is the final bit of a long last

bus: Make remove callback return void

The driver core ignores the return value of this callback because there
is only little it can do when a device disappears.

This is the final bit of a long lasting cleanup quest where several
buses were converted to also return void from their remove callback.
Additionally some resource leaks were fixed that were caused by drivers
returning an error code in the expectation that the driver won't go
away.

With struct bus_type::remove returning void it's prevented that newly
implemented buses return an ignored error code and so don't anticipate
wrong expectations for driver authors.

Reviewed-by: Tom Rix <[email protected]> (For fpga)
Reviewed-by: Mathieu Poirier <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]> (For drivers/s390 and drivers/vfio)
Acked-by: Russell King (Oracle) <[email protected]> (For ARM, Amba and related parts)
Acked-by: Mark Brown <[email protected]>
Acked-by: Chen-Yu Tsai <[email protected]> (for sunxi-rsb)
Acked-by: Pali Rohár <[email protected]>
Acked-by: Mauro Carvalho Chehab <[email protected]> (for media)
Acked-by: Hans de Goede <[email protected]> (For drivers/platform)
Acked-by: Alexandre Belloni <[email protected]>
Acked-By: Vinod Koul <[email protected]>
Acked-by: Juergen Gross <[email protected]> (For xen)
Acked-by: Lee Jones <[email protected]> (For mfd)
Acked-by: Johannes Thumshirn <[email protected]> (For mcb)
Acked-by: Johan Hovold <[email protected]>
Acked-by: Srinivas Kandagatla <[email protected]> (For slimbus)
Acked-by: Kirti Wankhede <[email protected]> (For vfio)
Acked-by: Maximilian Luz <[email protected]>
Acked-by: Heikki Krogerus <[email protected]> (For ulpi and typec)
Acked-by: Samuel Iglesias Gonsálvez <[email protected]> (For ipack)
Acked-by: Geoff Levand <[email protected]> (For ps3)
Acked-by: Yehezkel Bernat <[email protected]> (For thunderbolt)
Acked-by: Alexander Shishkin <[email protected]> (For intel_th)
Acked-by: Dominik Brodowski <[email protected]> (For pcmcia)
Acked-by: Rafael J. Wysocki <[email protected]> (For ACPI)
Acked-by: Bjorn Andersson <[email protected]> (rpmsg and apr)
Acked-by: Srinivas Pandruvada <[email protected]> (For intel-ish-hid)
Acked-by: Dan Williams <[email protected]> (For CXL, DAX, and NVDIMM)
Acked-by: William Breathitt Gray <[email protected]> (For isa)
Acked-by: Stefan Richter <[email protected]> (For firewire)
Acked-by: Benjamin Tissoires <[email protected]> (For hid)
Acked-by: Thorsten Scherer <[email protected]> (For siox)
Acked-by: Sven Van Asbroeck <[email protected]> (For anybuss)
Acked-by: Ulf Hansson <[email protected]> (For MMC)
Acked-by: Wolfram Sang <[email protected]> # for I2C
Acked-by: Sudeep Holla <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Acked-by: Dmitry Torokhov <[email protected]>
Acked-by: Finn Thain <[email protected]>
Signed-off-by: Uwe Kleine-König <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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rpmsg: core: Add driver_data for rpmsg_device_id

Most device_id structs provide a driver_data field that can be used
by drivers to associate data more easily for a particular device ID.
Add the same

rpmsg: core: Add driver_data for rpmsg_device_id

Most device_id structs provide a driver_data field that can be used
by drivers to associate data more easily for a particular device ID.
Add the same for the rpmsg_device_id.

Cc: Bjorn Andersson <[email protected]>
Signed-off-by: Stephan Gerhold <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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rpmsg: core: Add channel creation internal API

Add the channel creation API as a first step to be able to define the
name service announcement as a rpmsg driver independent from the RPMsg
virtio bus

rpmsg: core: Add channel creation internal API

Add the channel creation API as a first step to be able to define the
name service announcement as a rpmsg driver independent from the RPMsg
virtio bus.

Tested-by: Guennadi Liakhovetski <[email protected]>
Signed-off-by: Arnaud Pouliquen <[email protected]>
Signed-off-by: Mathieu Poirier <[email protected]>
Reviewed-by: Guennadi Liakhovetski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Andersson <[email protected]>

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rpmsg: Guard against null endpoint ops in destroy

In RPMSG GLINK the chrdev device will allocate an ept as part of the
rpdev creation. This device will not register endpoint ops even though
it has a

rpmsg: Guard against null endpoint ops in destroy

In RPMSG GLINK the chrdev device will allocate an ept as part of the
rpdev creation. This device will not register endpoint ops even though
it has an allocated ept. Protect against the case where the device is
being destroyed.

Signed-off-by: Chris Lew <[email protected]>
Signed-off-by: Arun Kumar Neelakantam <[email protected]>
Signed-off-by: Deepak Kumar Singh <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Andersson <[email protected]>

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rpmsg: fix a comment typo for rpmsg_device_match()

Should be 'a' rather than 'an'.

Signed-off-by: WANG Wenhu <[email protected]>
Link: https://lore.kernel.org/r/20200313165049.62907-1-wenhu.wang@

rpmsg: fix a comment typo for rpmsg_device_match()

Should be 'a' rather than 'an'.

Signed-off-by: WANG Wenhu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Andersson <[email protected]>

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rpmsg: core: fix comments

Minor typos, grammar and copy/paste issues. Fix for consistency. No
functional or semantic change.

Signed-off-by: Pierre-Louis Bossart <[email protected]

rpmsg: core: fix comments

Minor typos, grammar and copy/paste issues. Fix for consistency. No
functional or semantic change.

Signed-off-by: Pierre-Louis Bossart <[email protected]>
Signed-off-by: Bjorn Andersson <[email protected]>

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rpmsg: core: Make remove handler for rpmsg driver optional.

Most other bus (for example, SPI, i2c) have the remove handler for
driver optional. Make remove handler for rpmsg driver optional too.

Si

rpmsg: core: Make remove handler for rpmsg driver optional.

Most other bus (for example, SPI, i2c) have the remove handler for
driver optional. Make remove handler for rpmsg driver optional too.

Signed-off-by: Pi-Hsun Shih <[email protected]>
Signed-off-by: Bjorn Andersson <[email protected]>

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rpmsg: core: add support to power domains for devices

Some of the rpmsg devices need to switch on power domains to communicate
with remote processor. For example on Qualcomm DB820c platform LPASS
po

rpmsg: core: add support to power domains for devices

Some of the rpmsg devices need to switch on power domains to communicate
with remote processor. For example on Qualcomm DB820c platform LPASS
power domain needs to switched on for any kind of audio services.
This patch adds the missing power domain support in rpmsg core.

Without this patch attempting to play audio via QDSP on DB820c would
reboot the system.

Signed-off-by: Srinivas Kandagatla <[email protected]>
Signed-off-by: Bjorn Andersson <[email protected]>

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