linux-toradex.git/drivers/base/driver.c, branch v5.19-rc1

driver core: Extend deferred probe timeout on driver registration

2022-05-19T17:32:33+00:00

The deferred probe timer that's used for this currently starts at
late_initcall and runs for driver_deferred_probe_timeout seconds. The
assumption being that all available drivers would be loaded and
registered before the timer expires. This means, the
driver_deferred_probe_timeout has to be pretty large for it to cover the
worst case. But if we set the default value for it to cover the worst
case, it would significantly slow down the average case. For this
reason, the default value is set to 0.

Also, with CONFIG_MODULES=y and the current default values of
driver_deferred_probe_timeout=0 and fw_devlink=on, devices with missing
drivers will cause their consumer devices to always defer their probes.
This is because device links created by fw_devlink defer the probe even
before the consumer driver's probe() is called.

Instead of a fixed timeout, if we extend an unexpired deferred probe
timer on every successful driver registration, with the expectation more
modules would be loaded in the near future, then the default value of
driver_deferred_probe_timeout only needs to be as long as the worst case
time difference between two consecutive module loads.

So let's implement that and set the default value to 10 seconds when
CONFIG_MODULES=y.

Cc: Greg Kroah-Hartman 
Cc: "Rafael J. Wysocki" 
Cc: Rob Herring 
Cc: Linus Walleij 
Cc: Will Deacon 
Cc: Ulf Hansson 
Cc: Kevin Hilman 
Cc: Thierry Reding 
Cc: Mark Brown 
Cc: Pavel Machek 
Cc: Geert Uytterhoeven 
Cc: Yoshihiro Shimoda 
Cc: Paul Kocialkowski 
Cc: linux-gpio@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: iommu@lists.linux-foundation.org
Reviewed-by: Mark Brown 
Acked-by: Rob Herring 
Signed-off-by: Saravana Kannan 
Link: https://lore.kernel.org/r/20220429220933.1350374-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman

driver: platform: Add helper for safer setting of driver_override

2022-04-22T15:13:53+00:00

Several core drivers and buses expect that driver_override is a
dynamically allocated memory thus later they can kfree() it.

However such assumption is not documented, there were in the past and
there are already users setting it to a string literal. This leads to
kfree() of static memory during device release (e.g. in error paths or
during unbind):

    kernel BUG at ../mm/slub.c:3960!
    Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
    ...
    (kfree) from [] (platform_device_release+0x88/0xb4)
    (platform_device_release) from [] (device_release+0x2c/0x90)
    (device_release) from [] (kobject_put+0xec/0x20c)
    (kobject_put) from [] (exynos5_clk_probe+0x154/0x18c)
    (exynos5_clk_probe) from [] (platform_drv_probe+0x6c/0xa4)
    (platform_drv_probe) from [] (really_probe+0x280/0x414)
    (really_probe) from [] (driver_probe_device+0x78/0x1c4)
    (driver_probe_device) from [] (bus_for_each_drv+0x74/0xb8)
    (bus_for_each_drv) from [] (__device_attach+0xd4/0x16c)
    (__device_attach) from [] (bus_probe_device+0x88/0x90)
    (bus_probe_device) from [] (device_add+0x3dc/0x62c)
    (device_add) from [] (of_platform_device_create_pdata+0x94/0xbc)
    (of_platform_device_create_pdata) from [] (of_platform_bus_create+0x1a8/0x4fc)
    (of_platform_bus_create) from [] (of_platform_bus_create+0x20c/0x4fc)
    (of_platform_bus_create) from [] (of_platform_populate+0x84/0x118)
    (of_platform_populate) from [] (of_platform_default_populate_init+0xa0/0xb8)
    (of_platform_default_populate_init) from [] (do_one_initcall+0x8c/0x404)

Provide a helper which clearly documents the usage of driver_override.
This will allow later to reuse the helper and reduce the amount of
duplicated code.

Convert the platform driver to use a new helper and make the
driver_override field const char (it is not modified by the core).

Reviewed-by: Rafael J. Wysocki 
Acked-by: Rafael J. Wysocki 
Signed-off-by: Krzysztof Kozlowski 
Link: https://lore.kernel.org/r/20220419113435.246203-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Greg Kroah-Hartman

drivers: base: Convert to printk alias functions

2020-07-10T12:16:44+00:00

The file mixes printk calls together with calls to pr_*().
Covert to printk alias functions to unify the code.

Signed-off-by: Matthias Brugger 
Link: https://lore.kernel.org/r/20200608095217.21162-2-matthias.bgg@kernel.org
Signed-off-by: Greg Kroah-Hartman

device.h: move 'struct driver' stuff out to device/driver.h

2019-12-16T09:11:16+00:00

device.h has everything and the kitchen sink when it comes to struct
device things, so split out the struct driver things things to a
separate .h file to make things easier to maintain and manage over time.

Cc: "Rafael J. Wysocki" 
Cc: Suzuki K Poulose 
Cc: Saravana Kannan 
Cc: Heikki Krogerus 
Link: https://lore.kernel.org/r/20191209193303.1694546-7-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver_find_device: Unify the match function with class_find_device()

2019-06-24T03:22:31+00:00

The driver_find_device() accepts a match function pointer to
filter the devices for lookup, similar to bus/class_find_device().
However, there is a minor difference in the prototype for the
match parameter for driver_find_device() with the now unified
version accepted by {bus/class}_find_device(), where it doesn't
accept a "const" qualifier for the data argument. This prevents
us from reusing the generic match functions for driver_find_device().

For this reason, change the prototype of the driver_find_device() to
make the "match" parameter in line with {bus/class}_find_device()
and adjust its callers to use the const qualifier. Also, we could
now promote the "data" parameter to const as we pass it down
as a const parameter to the match functions.

Cc: Corey Minyard 
Cc: Russell King 
Cc: Thierry Reding 
Cc: Greg Kroah-Hartman 
Cc: "Rafael J. Wysocki" 
Cc: Will Deacon 
Cc: Joerg Roedel 
Cc: Peter Oberparleiter 
Cc: Sebastian Ott 
Cc: David Airlie 
Cc: Daniel Vetter 
Cc: Nehal Shah 
Cc: Shyam Sundar S K 
Cc: Lee Jones 
Cc: Christian Borntraeger 
Signed-off-by: Suzuki K Poulose 
Signed-off-by: Greg Kroah-Hartman

driver-core: return EINVAL error instead of BUG_ON()

2018-05-25T16:18:45+00:00

I triggerd the BUG_ON() in driver_register() when booting a domU Xen
domain. Since there was no contextual information logged, I needed to
attach kgdb to determine the culprit (the wmi-bmof driver in my
case). The BUG_ON() was added in commit f48f3febb2cb ("driver-core: do
not register a driver with bus_type not registered").

Instead of running into a BUG_ON() we print an error message
identifying the, likely faulty, driver but continue booting.

Signed-off-by: Florian Schmaus 
Signed-off-by: Greg Kroah-Hartman

drivers: base: omit redundant interations

2017-12-18T15:47:27+00:00

When error happens, these interators return the error, no interation should
be continued, so make the change for getting out of while immediately.

Signed-off-by: Gimcuan Hui 
Signed-off-by: Greg Kroah-Hartman

driver core: Remove redundant license text

2017-12-07T17:36:44+00:00

Now that the SPDX tag is in all driver core files, that identifies the
license in a specific and legally-defined manner.  So the extra GPL text
wording can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text.  And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Johannes Berg 
Cc: "Luis R. Rodriguez" 
Signed-off-by: Greg Kroah-Hartman

driver core: add SPDX identifiers to all driver core files

2017-12-07T17:36:43+00:00

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the driver core files files with the correct SPDX license
identifier based on the license text in the file itself.  The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Johannes Berg 
Cc: "Luis R. Rodriguez" 
Cc: William Breathitt Gray 
Cc: Thomas Gleixner 
Cc: Kate Stewart 
Cc: Philippe Ombredanne 
Signed-off-by: Greg Kroah-Hartman

driver core: add missing blank line after declaration

2015-03-25T13:36:30+00:00

Found using checkpatch.pl
Signed-off-by: Lavinia Tache 
Signed-off-by: Greg Kroah-Hartman