usb: gadget: ffs: remove ENTER() macro

ENTER() used to show function name which called during runtime, ftrace can
be used to get same information, let's remove it.

Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
Link: https://lore.kernel.org/r/1679911940-4727-1-git-send-email-quic_linyyuan@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: gadget: Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style in
header files related to USB peripheral controller drivers.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

usb: gadget: Change Andrzej Pietrasiewicz's e-mail address

My @samusung.com address is going to cease existing soon, so change it to
an address which can actually be used to contact me.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

USB: gadget: function: Remove redundant license text

Now that the SPDX tag is in all USB 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: Oliver Neukum <oneukum@suse.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Jerry Zhang <zhangjerry@google.com>
Cc: John Keeping <john@metanate.com>
Cc: Krzysztof Opasiak <k.opasiak@samsung.com>
Cc: Abdulhadi Mohamed <abdulahhadi2@gmail.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Janusz Dziedzic <januszx.dziedzic@linux.intel.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Vincent Pelletier <plr.vincent@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: add SPDX identifiers to all remaining files in drivers/usb/

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/usb/ and include/linux/usb* 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: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: gadget: ffs: handle I/O completion in-order

By submitting completed transfers to the system workqueue there is no
guarantee that completion events will be queued up in the correct order,
as in multi-processor systems there is a thread running for each
processor and the work items are not bound to a particular core.

This means that several completions are in the queue at the same time,
they may be processed in parallel and complete out of order, resulting
in data appearing corrupt when read by userspace.

Create a single-threaded workqueue for FunctionFS so that data completed
requests is passed to userspace in the order in which they complete.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

usb: gadget: function: f_fs: Move epfile waitqueue to ffs_data.

There were individual waitqueues for each epfile but eps_enable
would iterate through all of them, resulting in essentially the
same wakeup time.

The waitqueue represents the function being enabled, so a central
waitqueue in ffs_data makes more sense and is less redundant.

Also use wake_up_interruptible to reflect use of
wait_event_interruptible.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Jerry Zhang <zhangjerry@google.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

usb: gadget: f_fs: simplify ffs_dev name handling

Currently ffs_dev::name can be either allocated by the client of
the ffs_dev structure or by the f_fs.c core itself. The former
is used by g_ffs while the latter happens with configfs.

Historically, g_ffs did not need to allocate separate buffer for
the name so what is now f_fs.c core never cared about freeing
that space. With configfs the name needs to be copied since the
memory is not guaranteed to be availeble after ffs_set_inst_name
finishes.

The complication is therefore here to avoid allocations in the
g_ffs case but it complicates the code inproportinally to
benefits it provides. In particular, g_ffs is considered
‘legacy’ so optimising for its sake is unlikely to be worth the
effort.

With that observation in mind, simplify the code by unifying the
code paths in g_ffs and configfs paths. Furthermore, instead of
allocating a new buffer for the name, simply embed it in the
ffs_dev structure. This further makes the memory management
less convoluted and error-prone.

The configfs interface for functionfs imposed a limit of 40
characters for the name so this results in a 41-byte buffer
added to the structure. (For short names this may lead to
wasted memory but the actual amount is not immediately obvious
and depends on pointer size and which slab buckets the structure
and name would fall into).

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers, usb: convert ffs_data.ref from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: gadget: f_fs: Accept up to 30 endpoints.

It is allowed by the USB specification to enabled same-address, opposite-
direction endpoints simultaneously, which means 30 non-zero endpoints
are allowed. So double eps_addrmap length to 30.
The original code only accepted 14 descriptors out of a likely intended 15
(as there are 15 endpoint addresses, ignoring direction), because the first
eps_addrmap entry is unused (it is a placeholder for endpoint zero). So
increase eps_addrmap length by one to 31.

Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

usb: gadget: ffs: add eventfd notification about ffs events

Add eventfd which notifies userspace about ep0 events and AIO completion
events. It simplifies using of FunctionFS with event loop, because now
we need to poll on single file (instead of polling on ep0 and eventfd's
supplied to AIO layer).

FunctionFS eventfd is not triggered if another eventfd is supplied to
AIO layer (in AIO request). It can be useful, for example, when we want
to handle AIO transations for chosen endpoint in separate thread.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: gadget: f_fs: add "no_disconnect" mode

Since we can compose gadgets from many functions, there is the problem
related to gadget breakage while FunctionFS daemon being closed. FFS
function is userspace code so there is no way to know when it will close
files (it doesn't matter what is the reason of this situation, it can
be daemon logic, program breakage, process kill or any other). So when
we have another function in gadget which, for example, sends some amount
of data, does some software update or implements some real-time functionality,
we may want to keep the gadget connected despite FFS function is no longer
functional.

We can't just remove one of functions from gadget since it has been
enumerated, so the only way to keep entire gadget working is to make
broken FFS function deactivated but still visible to host. For this
purpose this patch introduces "no_disconnect" mode. It can be enabled
by setting mount option "no_disconnect=1", and results with defering
function disconnect to the moment of reopen ep0 file or filesystem
unmount. After closing all endpoint files, FunctionFS is set to state
FFS_DEACTIVATED.

When ffs->state == FFS_DEACTIVATED:
- function is still bound and visible to host,
- setup requests are automatically stalled,
- transfers on other endpoints are refused,
- epfiles, except ep0, are deleted from the filesystem,
- opening ep0 causes the function to be closed, and then FunctionFS
is ready for descriptors and string write,
- altsetting change causes the function to be closed - we want to keep
function alive until another functions are potentialy used, altsetting
change means that another configuration is being selected or USB cable
was unplugged, which indicates that we don't need to stay longer in
FFS_DEACTIVATED state
- unmounting of the FunctionFS instance causes the function to be closed.

Tested-by: David Cohen <david.a.cohen@linux.intel.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: gadget: f_fs: virtual endpoint address mapping

This patch introduces virtual endpoint address mapping. It separates
function logic form physical endpoint addresses making it more hardware
independent.

Following modifications changes user space API, so to enable them user
have to switch on the FUNCTIONFS_VIRTUAL_ADDR flag in descriptors.

Endpoints are now refered using virtual endpoint addresses chosen by
user in endpoint descpriptors. This applies to each context when endpoint
address can be used:
- when accessing endpoint files in FunctionFS filesystemi (in file name),
- in setup requests directed to specific endpoint (in wIndex field),
- in descriptors returned by FUNCTIONFS_ENDPOINT_DESC ioctl.

In endpoint file names the endpoint address number is formatted as
double-digit hexadecimal value ("ep%02x") which has few advantages -
it is easy to parse, allows to easly recognize endpoint direction basing
on its name (IN endpoint number starts with digit 8, and OUT with 0)
which can be useful for debugging purpose, and it makes easier to introduce
further features allowing to use each endpoint number in both directions
to have more endpoints available for function if hardware supports this
(for example we could have ep01 which is endpoint 1 with OUT direction,
and ep81 which is endpoint 1 with IN direction).

Physical endpoint address can be still obtained using ioctl named
FUNCTIONFS_ENDPOINT_REVMAP, but now it's not neccesary to handle
USB transactions properly.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: gadget: f_fs: fix the redundant ep files problem

Up to now, when endpoint addresses in descriptors were non-consecutive,
there were created redundant files, which could cause problems in kernel,
when user tried to read/write to them. It was result of fact that maximum
endpoint address was taken as total number of endpoints in function.

This patch adds endpoint descriptors counting and storing their addresses
in eps_addrmap to verify their cohesion in each speed.

Endpoint address map would be also useful for further features, just like
vitual endpoint address mapping.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: gadget: Gadget directory cleanup - group usb functions

The drivers/usb/gadget directory contains many files.
Files which are related can be distributed into separate directories.
This patch moves the USB functions implementations into a separate directory.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>