greybus: Avoid fake flexible array for response data

FORTIFY_SOURCE has been ignoring 0-sized destinations while the kernel
code base has been converted to flexible arrays. In order to enforce
the 0-sized destinations (e.g. with __counted_by), the remaining 0-sized
destinations need to be handled. Instead of converting an empty struct
into using a flexible array, just directly use a pointer without any
additional indirection. Remove struct gb_bootrom_get_firmware_response
and struct gb_fw_download_fetch_firmware_response.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20240304211940.it.083-kees@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: greybus: Remove usage of the deprecated ida_simple_xx() API

ida_alloc() and ida_free() should be preferred to the deprecated
ida_simple_get() and ida_simple_remove().

Note that the upper limit of ida_simple_get() is exclusive, buInputt the one of
ida_alloc_range()/ida_alloc_max() is inclusive. So a -1 has been added when
needed.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/2e7bbdaf8a495bb1273396395b5c779363287581.1705350141.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: greybus: move core include files to include/linux/greybus/

With the goal of moving the core of the greybus code out of staging, the
include files need to be moved to include/linux/greybus.h and
include/linux/greybus/

Cc: Vaibhav Hiremath <hvaibhav.linux@gmail.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Vaibhav Agarwal <vaibhav.sr@gmail.com>
Cc: Rui Miguel Silva <rmfrfs@gmail.com>
Cc: David Lin <dtwlin@gmail.com>
Cc: "Bryan O'Donoghue" <pure.logic@nexus-software.ie>
Cc: greybus-dev@lists.linaro.org
Cc: devel@driverdev.osuosl.org
Acked-by: Mark Greer <mgreer@animalcreek.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Alex Elder <elder@kernel.org>
Link: https://lore.kernel.org/r/20190825055429.18547-8-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: greybus: Remove redundant license text

Now that the SPDX tag is in all greybus 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: Vaibhav Hiremath <hvaibhav.linux@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Acked-by: Vaibhav Agarwal <vaibhav.sr@gmail.com>
Acked-by: David Lin <dtwlin@gmail.com>
Acked-by: Johan Hovold <johan@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Mark Greer <mgreer@animalcreek.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Acked-by: "Bryan O'Donoghue" <pure.logic@nexus-software.ie>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: greybus: add SPDX identifiers to all greybus driver files

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

Update the drivers/staging/greybus 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: Vaibhav Hiremath <hvaibhav.linux@gmail.com>
Cc: "Bryan O'Donoghue" <pure.logic@nexus-software.ie>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Acked-by: Vaibhav Agarwal <vaibhav.sr@gmail.com>
Acked-by: David Lin <dtwlin@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Acked-by: Johan Hovold <johan@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Mark Greer <mgreer@animalcreek.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: greybus: fix "line over 80 characters" coding style issues

This patch fixes only obvious lines.
There are still more issues.

Signed-off-by: Gioh Kim <gi-oh.kim@profitbricks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

greybus: firmware: s/should/must

Replace 'should' with 'must' to clear the expectation a bit more.

Reported-by: Alex Elder <alex.elder@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: firmware: s/_LEN/_SIZE

Alex Elder pointed out that the macros also count the trailing NULL
('\0') character and so it should be using SIZE instead of LEN.

This patch makes that change.

Reported-by: Alex Elder <alex.elder@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: firmware: Remove extra parenthesis

Remove the unnecessary parenthesis.

Reported-by: Alex Elder <alex.elder@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: firmware: use 'tag' instead of 'firmware_tag'

We already have another direct pointer for this, use that instead.

Testing Done: Compiled.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: move all firmware prefix strings to one place

The firmware prefix is hard-coded in a few different places. Put it all
in one handy #define, for when/if we ever decide to change it in the
future...

Testing: 'strings gb-firmware.ko gb-bootrom.ko | grep ara_' produced the
same output before and after this patch.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sandeep Patil <sspatil@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: fw-download: Replace timer with delayed-work

The timeout-handlers need to call routines that can sleep and those
can't be called from interrupt context. The timer-handler is called in
interrupt context and so will hit a BUG() in vmalloc.c.

This patch moves away from timers to delayed-work, whose timeout handler
gets called in process context and can call the sleep-able routines
safely.

Note that this issue wasn't hit earlier when the initial patch for
timeouts was implemented due to some issues in the build arche_420. But
with the new build arche_440, the BUG started crashing the phone on
timeouts and so this fix is required.

Tested on EVT 1.5 by triggering fake timeouts, by not sending
release-firmware request for example. This is tested with build
arche_440.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: fw-download: Introduce timeouts for firmware downloads

As per greybus specification, the AP can apply, implementation
dependent, timeouts for:

- The time interval between the Find Firmware Response and the first
Fetch Firmware Request.
- The time interval between a Fetch Firmware Response and the next Fetch
Firmware Request.
- The time interval between a Fetch Firmware Response and the Release
Firmware Request.
- The time interval between the Find Firmware Response and the Release
Firmware Request.

This patch implements those timeouts.

The timeout period for the first three cases is fixed to one-second and
the timeout for the last one is finalized at runtime, dependent on the
total size of the firmware.

There can be two possible paths now, which may race for freeing or
getting the 'struct fw_request'. They are:
- Request handler: initiated from the Module side.
- Timeout handler: initiated on timeout of the programmed timer.

And so a mutex is added to avoid races.

Every caller which needs to access the 'struct fw_request' increments
the reference count, so that the structure doesn't get freed in
parallel. Once the structure is freed and reference is put by all the
users, the structure is freed.

If we timeout while waiting for a request from the Module, the AP frees
the 'struct fw_request', but does *not* free the request-id. This is
done to guarantee that a delayed request from the Module for the expired
id, doesn't get access to a new 'struct fw_request' allocated later with
the same id.

Tested with gbsim by hacking its code to delay the release request and
indefinitely fetch the same section of the firmware package. Both timed
out on the AP side and the 'struct fw_request' is free properly. Further
requests work fine after few are timed out. And rmmod (followed by more
similar testing) works just fine.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: fw-download: Manage firmware requests with kref

This patch updates the fw-download core to manage firmware requests with
kref. This is required for the next patch, which will introduce timeouts
for firmware downloads.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: fw-download: Create a macro for length of firmware file's name

Create a macro representing the length of the firmware file's name and
use that instead of using magic number in the code.

Suggested-by: Greg Kroah-Hartman <gregkh@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

greybus: firmware: Add firmware-download protocol driver

This patch adds Firmware Download Protocol support to firmware core,
which allows an Interface to download a firmware package over Unipro.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Jun Li <li_jun@projectara.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>