In an entirely unrelated discussion where I pointed out a stupid thinko
of mine, Rasmus piped up and noted that that obvious mistake already
existed elsewhere in the kernel tree.
An "error pointer" is the negative error value encoded as a pointer,
making the whole "return error or valid pointer" use-case simple and
straightforward. We use it all over the kernel.
But the key here is that errors are _negative_ error numbers, not the
horrid UNIX user-level model of "-1 and the value of 'errno'".
The Apple mailbox driver used the positive error values, and thus just
returned invalid normal pointers instead of actual errors.
Of course, the reason nobody ever noticed is that the errors presumably
never actually happen, so this is fixing a conceptual bug rather than an
actual one.
Reported-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Link: https://lore.kernel.org/all/5c30afe0-f9fb-45d5-9333-dd914a1ea93a@prevas.dk/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other and pull in various other headers. In
preparation to fix this, adjust the includes for what is actually needed.
platform_device.h is implicitly included by of_platform.h, but that's going
to be removed.
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Hector Martin <marcan@marcan.st>
This new driver is based on the existing apple-mailbox driver, but
replaces the usage of the mailbox subsystem with directly exported
symbols.
As part of this refactor, this adds support for using the hardware FIFOs
(not supported in mailbox) and implicitly fixes a bunch of bugs caused
by bad interactions with the mailbox subsystem. It also adds runtime-PM
support.
The new config symbol is APPLE_MBOX, while the module name remains
identical ("apple-mailbox"). The configs are mutually exclusive in
Kconfig, to avoid conflicts.
Acked-by: Eric Curtin <ecurtin@redhat.com>
Acked-by: Neal Gompa <neal@gompa.dev>
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Hector Martin <marcan@marcan.st>
