ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/drivers/usb/gadget/function/f_fs.c b/marvell/linux/drivers/usb/gadget/function/f_fs.c
new file mode 100644
index 0000000..9b5f9d5
--- /dev/null
+++ b/marvell/linux/drivers/usb/gadget/function/f_fs.c
@@ -0,0 +1,3911 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * f_fs.c -- user mode file system API for USB composite function controllers
+ *
+ * Copyright (C) 2010 Samsung Electronics
+ * Author: Michal Nazarewicz <mina86@mina86.com>
+ *
+ * Based on inode.c (GadgetFS) which was:
+ * Copyright (C) 2003-2004 David Brownell
+ * Copyright (C) 2003 Agilent Technologies
+ */
+
+
+/* #define DEBUG */
+/* #define VERBOSE_DEBUG */
+
+#include <linux/blkdev.h>
+#include <linux/pagemap.h>
+#include <linux/export.h>
+#include <linux/fs_parser.h>
+#include <linux/hid.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/sched/signal.h>
+#include <linux/uio.h>
+#include <linux/vmalloc.h>
+#include <asm/unaligned.h>
+
+#include <linux/usb/ccid.h>
+#include <linux/usb/composite.h>
+#include <linux/usb/functionfs.h>
+
+#include <linux/aio.h>
+#include <linux/mmu_context.h>
+#include <linux/poll.h>
+#include <linux/eventfd.h>
+
+#include "u_fs.h"
+#include "u_f.h"
+#include "u_os_desc.h"
+#include "configfs.h"
+
+#define FUNCTIONFS_MAGIC 0xa647361 /* Chosen by a honest dice roll ;) */
+
+/* Reference counter handling */
+static void ffs_data_get(struct ffs_data *ffs);
+static void ffs_data_put(struct ffs_data *ffs);
+/* Creates new ffs_data object. */
+static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
+ __attribute__((malloc));
+
+/* Opened counter handling. */
+static void ffs_data_opened(struct ffs_data *ffs);
+static void ffs_data_closed(struct ffs_data *ffs);
+
+/* Called with ffs->mutex held; take over ownership of data. */
+static int __must_check
+__ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
+static int __must_check
+__ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
+
+
+/* The function structure ***************************************************/
+
+struct ffs_ep;
+
+struct ffs_function {
+ struct usb_configuration *conf;
+ struct usb_gadget *gadget;
+ struct ffs_data *ffs;
+
+ struct ffs_ep *eps;
+ u8 eps_revmap[16];
+ short *interfaces_nums;
+
+ struct usb_function function;
+};
+
+
+static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
+{
+ return container_of(f, struct ffs_function, function);
+}
+
+
+static inline enum ffs_setup_state
+ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
+{
+ return (enum ffs_setup_state)
+ cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
+}
+
+
+static void ffs_func_eps_disable(struct ffs_function *func);
+static int __must_check ffs_func_eps_enable(struct ffs_function *func);
+
+static int ffs_func_bind(struct usb_configuration *,
+ struct usb_function *);
+static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
+static void ffs_func_disable(struct usb_function *);
+static int ffs_func_setup(struct usb_function *,
+ const struct usb_ctrlrequest *);
+static bool ffs_func_req_match(struct usb_function *,
+ const struct usb_ctrlrequest *,
+ bool config0);
+static void ffs_func_suspend(struct usb_function *);
+static void ffs_func_resume(struct usb_function *);
+
+
+static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
+static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
+
+
+/* The endpoints structures *************************************************/
+
+struct ffs_ep {
+ struct usb_ep *ep; /* P: ffs->eps_lock */
+ struct usb_request *req; /* P: epfile->mutex */
+
+ /* [0]: full speed, [1]: high speed, [2]: super speed */
+ struct usb_endpoint_descriptor *descs[3];
+
+ u8 num;
+
+ int status; /* P: epfile->mutex */
+};
+
+struct ffs_epfile {
+ /* Protects ep->ep and ep->req. */
+ struct mutex mutex;
+
+ struct ffs_data *ffs;
+ struct ffs_ep *ep; /* P: ffs->eps_lock */
+
+ struct dentry *dentry;
+
+ /*
+ * Buffer for holding data from partial reads which may happen since
+ * we’re rounding user read requests to a multiple of a max packet size.
+ *
+ * The pointer is initialised with NULL value and may be set by
+ * __ffs_epfile_read_data function to point to a temporary buffer.
+ *
+ * In normal operation, calls to __ffs_epfile_read_buffered will consume
+ * data from said buffer and eventually free it. Importantly, while the
+ * function is using the buffer, it sets the pointer to NULL. This is
+ * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
+ * can never run concurrently (they are synchronised by epfile->mutex)
+ * so the latter will not assign a new value to the pointer.
+ *
+ * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
+ * valid) and sets the pointer to READ_BUFFER_DROP value. This special
+ * value is crux of the synchronisation between ffs_func_eps_disable and
+ * __ffs_epfile_read_data.
+ *
+ * Once __ffs_epfile_read_data is about to finish it will try to set the
+ * pointer back to its old value (as described above), but seeing as the
+ * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
+ * the buffer.
+ *
+ * == State transitions ==
+ *
+ * • ptr == NULL: (initial state)
+ * ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
+ * ◦ __ffs_epfile_read_buffered: nop
+ * ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
+ * ◦ reading finishes: n/a, not in ‘and reading’ state
+ * • ptr == DROP:
+ * ◦ __ffs_epfile_read_buffer_free: nop
+ * ◦ __ffs_epfile_read_buffered: go to ptr == NULL
+ * ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
+ * ◦ reading finishes: n/a, not in ‘and reading’ state
+ * • ptr == buf:
+ * ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
+ * ◦ __ffs_epfile_read_buffered: go to ptr == NULL and reading
+ * ◦ __ffs_epfile_read_data: n/a, __ffs_epfile_read_buffered
+ * is always called first
+ * ◦ reading finishes: n/a, not in ‘and reading’ state
+ * • ptr == NULL and reading:
+ * ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
+ * ◦ __ffs_epfile_read_buffered: n/a, mutex is held
+ * ◦ __ffs_epfile_read_data: n/a, mutex is held
+ * ◦ reading finishes and …
+ * … all data read: free buf, go to ptr == NULL
+ * … otherwise: go to ptr == buf and reading
+ * • ptr == DROP and reading:
+ * ◦ __ffs_epfile_read_buffer_free: nop
+ * ◦ __ffs_epfile_read_buffered: n/a, mutex is held
+ * ◦ __ffs_epfile_read_data: n/a, mutex is held
+ * ◦ reading finishes: free buf, go to ptr == DROP
+ */
+ struct ffs_buffer *read_buffer;
+#define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
+
+ char name[5];
+
+ unsigned char in; /* P: ffs->eps_lock */
+ unsigned char isoc; /* P: ffs->eps_lock */
+
+ unsigned char _pad;
+};
+
+struct ffs_buffer {
+ size_t length;
+ char *data;
+ char storage[];
+};
+
+/* ffs_io_data structure ***************************************************/
+
+struct ffs_io_data {
+ bool aio;
+ bool read;
+
+ struct kiocb *kiocb;
+ struct iov_iter data;
+ const void *to_free;
+ char *buf;
+
+ struct mm_struct *mm;
+ struct work_struct work;
+
+ struct usb_ep *ep;
+ struct usb_request *req;
+ struct sg_table sgt;
+ bool use_sg;
+
+ struct ffs_data *ffs;
+};
+
+struct ffs_desc_helper {
+ struct ffs_data *ffs;
+ unsigned interfaces_count;
+ unsigned eps_count;
+};
+
+static int __must_check ffs_epfiles_create(struct ffs_data *ffs);
+static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
+
+static struct dentry *
+ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
+ const struct file_operations *fops);
+
+/* Devices management *******************************************************/
+
+DEFINE_MUTEX(ffs_lock);
+EXPORT_SYMBOL_GPL(ffs_lock);
+
+static struct ffs_dev *_ffs_find_dev(const char *name);
+static struct ffs_dev *_ffs_alloc_dev(void);
+static void _ffs_free_dev(struct ffs_dev *dev);
+static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data);
+static void ffs_release_dev(struct ffs_dev *ffs_dev);
+static int ffs_ready(struct ffs_data *ffs);
+static void ffs_closed(struct ffs_data *ffs);
+
+/* Misc helper functions ****************************************************/
+
+static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
+ __attribute__((warn_unused_result, nonnull));
+static char *ffs_prepare_buffer(const char __user *buf, size_t len)
+ __attribute__((warn_unused_result, nonnull));
+
+
+/* Control file aka ep0 *****************************************************/
+
+static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
+{
+ struct ffs_data *ffs = req->context;
+
+ complete(&ffs->ep0req_completion);
+}
+
+static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
+ __releases(&ffs->ev.waitq.lock)
+{
+ struct usb_request *req = ffs->ep0req;
+ int ret;
+
+ if (!req) {
+ spin_unlock_irq(&ffs->ev.waitq.lock);
+ return -EINVAL;
+ }
+
+ req->zero = len < le16_to_cpu(ffs->ev.setup.wLength);
+
+ spin_unlock_irq(&ffs->ev.waitq.lock);
+
+ req->buf = data;
+ req->length = len;
+
+ /*
+ * UDC layer requires to provide a buffer even for ZLP, but should
+ * not use it at all. Let's provide some poisoned pointer to catch
+ * possible bug in the driver.
+ */
+ if (req->buf == NULL)
+ req->buf = (void *)0xDEADBABE;
+
+ reinit_completion(&ffs->ep0req_completion);
+
+ ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
+ if (unlikely(ret < 0))
+ return ret;
+
+ ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
+ if (unlikely(ret)) {
+ usb_ep_dequeue(ffs->gadget->ep0, req);
+ return -EINTR;
+ }
+
+ ffs->setup_state = FFS_NO_SETUP;
+ return req->status ? req->status : req->actual;
+}
+
+static int __ffs_ep0_stall(struct ffs_data *ffs)
+{
+ if (ffs->ev.can_stall) {
+ pr_vdebug("ep0 stall\n");
+ usb_ep_set_halt(ffs->gadget->ep0);
+ ffs->setup_state = FFS_NO_SETUP;
+ return -EL2HLT;
+ } else {
+ pr_debug("bogus ep0 stall!\n");
+ return -ESRCH;
+ }
+}
+
+static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
+ size_t len, loff_t *ptr)
+{
+ struct ffs_data *ffs = file->private_data;
+ ssize_t ret;
+ char *data;
+
+ ENTER();
+
+ /* Fast check if setup was canceled */
+ if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
+ return -EIDRM;
+
+ /* Acquire mutex */
+ ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
+ if (unlikely(ret < 0))
+ return ret;
+
+ /* Check state */
+ switch (ffs->state) {
+ case FFS_READ_DESCRIPTORS:
+ case FFS_READ_STRINGS:
+ /* Copy data */
+ if (unlikely(len < 16)) {
+ ret = -EINVAL;
+ break;
+ }
+
+ data = ffs_prepare_buffer(buf, len);
+ if (IS_ERR(data)) {
+ ret = PTR_ERR(data);
+ break;
+ }
+
+ /* Handle data */
+ if (ffs->state == FFS_READ_DESCRIPTORS) {
+ pr_info("read descriptors\n");
+ ret = __ffs_data_got_descs(ffs, data, len);
+ if (unlikely(ret < 0))
+ break;
+
+ ffs->state = FFS_READ_STRINGS;
+ ret = len;
+ } else {
+ pr_info("read strings\n");
+ ret = __ffs_data_got_strings(ffs, data, len);
+ if (unlikely(ret < 0))
+ break;
+
+ ret = ffs_epfiles_create(ffs);
+ if (unlikely(ret)) {
+ ffs->state = FFS_CLOSING;
+ break;
+ }
+
+ ffs->state = FFS_ACTIVE;
+ mutex_unlock(&ffs->mutex);
+
+ ret = ffs_ready(ffs);
+ if (unlikely(ret < 0)) {
+ ffs->state = FFS_CLOSING;
+ return ret;
+ }
+
+ return len;
+ }
+ break;
+
+ case FFS_ACTIVE:
+ data = NULL;
+ /*
+ * We're called from user space, we can use _irq
+ * rather then _irqsave
+ */
+ spin_lock_irq(&ffs->ev.waitq.lock);
+ switch (ffs_setup_state_clear_cancelled(ffs)) {
+ case FFS_SETUP_CANCELLED:
+ ret = -EIDRM;
+ goto done_spin;
+
+ case FFS_NO_SETUP:
+ ret = -ESRCH;
+ goto done_spin;
+
+ case FFS_SETUP_PENDING:
+ break;
+ }
+
+ /* FFS_SETUP_PENDING */
+ if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
+ spin_unlock_irq(&ffs->ev.waitq.lock);
+ ret = __ffs_ep0_stall(ffs);
+ break;
+ }
+
+ /* FFS_SETUP_PENDING and not stall */
+ len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
+
+ spin_unlock_irq(&ffs->ev.waitq.lock);
+
+ data = ffs_prepare_buffer(buf, len);
+ if (IS_ERR(data)) {
+ ret = PTR_ERR(data);
+ break;
+ }
+
+ spin_lock_irq(&ffs->ev.waitq.lock);
+
+ /*
+ * We are guaranteed to be still in FFS_ACTIVE state
+ * but the state of setup could have changed from
+ * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
+ * to check for that. If that happened we copied data
+ * from user space in vain but it's unlikely.
+ *
+ * For sure we are not in FFS_NO_SETUP since this is
+ * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
+ * transition can be performed and it's protected by
+ * mutex.
+ */
+ if (ffs_setup_state_clear_cancelled(ffs) ==
+ FFS_SETUP_CANCELLED) {
+ ret = -EIDRM;
+done_spin:
+ spin_unlock_irq(&ffs->ev.waitq.lock);
+ } else {
+ /* unlocks spinlock */
+ ret = __ffs_ep0_queue_wait(ffs, data, len);
+ }
+ kfree(data);
+ break;
+
+ default:
+ ret = -EBADFD;
+ break;
+ }
+
+ mutex_unlock(&ffs->mutex);
+ return ret;
+}
+
+/* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
+static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
+ size_t n)
+ __releases(&ffs->ev.waitq.lock)
+{
+ /*
+ * n cannot be bigger than ffs->ev.count, which cannot be bigger than
+ * size of ffs->ev.types array (which is four) so that's how much space
+ * we reserve.
+ */
+ struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
+ const size_t size = n * sizeof *events;
+ unsigned i = 0;
+
+ memset(events, 0, size);
+
+ do {
+ events[i].type = ffs->ev.types[i];
+ if (events[i].type == FUNCTIONFS_SETUP) {
+ events[i].u.setup = ffs->ev.setup;
+ ffs->setup_state = FFS_SETUP_PENDING;
+ }
+ } while (++i < n);
+
+ ffs->ev.count -= n;
+ if (ffs->ev.count)
+ memmove(ffs->ev.types, ffs->ev.types + n,
+ ffs->ev.count * sizeof *ffs->ev.types);
+
+ spin_unlock_irq(&ffs->ev.waitq.lock);
+ mutex_unlock(&ffs->mutex);
+
+ return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
+}
+
+static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
+ size_t len, loff_t *ptr)
+{
+ struct ffs_data *ffs = file->private_data;
+ char *data = NULL;
+ size_t n;
+ int ret;
+
+ ENTER();
+
+ /* Fast check if setup was canceled */
+ if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
+ return -EIDRM;
+
+ /* Acquire mutex */
+ ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
+ if (unlikely(ret < 0))
+ return ret;
+
+ /* Check state */
+ if (ffs->state != FFS_ACTIVE) {
+ ret = -EBADFD;
+ goto done_mutex;
+ }
+
+ /*
+ * We're called from user space, we can use _irq rather then
+ * _irqsave
+ */
+ spin_lock_irq(&ffs->ev.waitq.lock);
+
+ switch (ffs_setup_state_clear_cancelled(ffs)) {
+ case FFS_SETUP_CANCELLED:
+ ret = -EIDRM;
+ break;
+
+ case FFS_NO_SETUP:
+ n = len / sizeof(struct usb_functionfs_event);
+ if (unlikely(!n)) {
+ ret = -EINVAL;
+ break;
+ }
+
+ if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
+ ret = -EAGAIN;
+ break;
+ }
+
+ if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
+ ffs->ev.count)) {
+ ret = -EINTR;
+ break;
+ }
+
+ /* unlocks spinlock */
+ return __ffs_ep0_read_events(ffs, buf,
+ min(n, (size_t)ffs->ev.count));
+
+ case FFS_SETUP_PENDING:
+ if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
+ spin_unlock_irq(&ffs->ev.waitq.lock);
+ ret = __ffs_ep0_stall(ffs);
+ goto done_mutex;
+ }
+
+ len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
+
+ spin_unlock_irq(&ffs->ev.waitq.lock);
+
+ if (likely(len)) {
+ data = kmalloc(len, GFP_KERNEL);
+ if (unlikely(!data)) {
+ ret = -ENOMEM;
+ goto done_mutex;
+ }
+ }
+
+ spin_lock_irq(&ffs->ev.waitq.lock);
+
+ /* See ffs_ep0_write() */
+ if (ffs_setup_state_clear_cancelled(ffs) ==
+ FFS_SETUP_CANCELLED) {
+ ret = -EIDRM;
+ break;
+ }
+
+ /* unlocks spinlock */
+ ret = __ffs_ep0_queue_wait(ffs, data, len);
+ if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
+ ret = -EFAULT;
+ goto done_mutex;
+
+ default:
+ ret = -EBADFD;
+ break;
+ }
+
+ spin_unlock_irq(&ffs->ev.waitq.lock);
+done_mutex:
+ mutex_unlock(&ffs->mutex);
+ kfree(data);
+ return ret;
+}
+
+static int ffs_ep0_open(struct inode *inode, struct file *file)
+{
+ struct ffs_data *ffs = inode->i_private;
+
+ ENTER();
+
+ if (unlikely(ffs->state == FFS_CLOSING))
+ return -EBUSY;
+
+ file->private_data = ffs;
+ ffs_data_opened(ffs);
+
+ return stream_open(inode, file);
+}
+
+static int ffs_ep0_release(struct inode *inode, struct file *file)
+{
+ struct ffs_data *ffs = file->private_data;
+
+ ENTER();
+
+ ffs_data_closed(ffs);
+
+ return 0;
+}
+
+static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
+{
+ struct ffs_data *ffs = file->private_data;
+ struct usb_gadget *gadget = ffs->gadget;
+ long ret;
+
+ ENTER();
+
+ if (code == FUNCTIONFS_INTERFACE_REVMAP) {
+ struct ffs_function *func = ffs->func;
+ ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
+ } else if (gadget && gadget->ops->ioctl) {
+ ret = gadget->ops->ioctl(gadget, code, value);
+ } else {
+ ret = -ENOTTY;
+ }
+
+ return ret;
+}
+
+static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
+{
+ struct ffs_data *ffs = file->private_data;
+ __poll_t mask = EPOLLWRNORM;
+ int ret;
+
+ poll_wait(file, &ffs->ev.waitq, wait);
+
+ ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
+ if (unlikely(ret < 0))
+ return mask;
+
+ switch (ffs->state) {
+ case FFS_READ_DESCRIPTORS:
+ case FFS_READ_STRINGS:
+ mask |= EPOLLOUT;
+ break;
+
+ case FFS_ACTIVE:
+ switch (ffs->setup_state) {
+ case FFS_NO_SETUP:
+ if (ffs->ev.count)
+ mask |= EPOLLIN;
+ break;
+
+ case FFS_SETUP_PENDING:
+ case FFS_SETUP_CANCELLED:
+ mask |= (EPOLLIN | EPOLLOUT);
+ break;
+ }
+ case FFS_CLOSING:
+ break;
+ case FFS_DEACTIVATED:
+ break;
+ }
+
+ mutex_unlock(&ffs->mutex);
+
+ return mask;
+}
+
+static const struct file_operations ffs_ep0_operations = {
+ .llseek = no_llseek,
+
+ .open = ffs_ep0_open,
+ .write = ffs_ep0_write,
+ .read = ffs_ep0_read,
+ .release = ffs_ep0_release,
+ .unlocked_ioctl = ffs_ep0_ioctl,
+ .poll = ffs_ep0_poll,
+};
+
+
+/* "Normal" endpoints operations ********************************************/
+
+static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
+{
+ ENTER();
+ if (likely(req->context)) {
+ struct ffs_ep *ep = _ep->driver_data;
+ ep->status = req->status ? req->status : req->actual;
+ complete(req->context);
+ }
+}
+
+static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
+{
+ ssize_t ret = copy_to_iter(data, data_len, iter);
+ if (likely(ret == data_len))
+ return ret;
+
+ if (unlikely(iov_iter_count(iter)))
+ return -EFAULT;
+
+ /*
+ * Dear user space developer!
+ *
+ * TL;DR: To stop getting below error message in your kernel log, change
+ * user space code using functionfs to align read buffers to a max
+ * packet size.
+ *
+ * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
+ * packet size. When unaligned buffer is passed to functionfs, it
+ * internally uses a larger, aligned buffer so that such UDCs are happy.
+ *
+ * Unfortunately, this means that host may send more data than was
+ * requested in read(2) system call. f_fs doesn’t know what to do with
+ * that excess data so it simply drops it.
+ *
+ * Was the buffer aligned in the first place, no such problem would
+ * happen.
+ *
+ * Data may be dropped only in AIO reads. Synchronous reads are handled
+ * by splitting a request into multiple parts. This splitting may still
+ * be a problem though so it’s likely best to align the buffer
+ * regardless of it being AIO or not..
+ *
+ * This only affects OUT endpoints, i.e. reading data with a read(2),
+ * aio_read(2) etc. system calls. Writing data to an IN endpoint is not
+ * affected.
+ */
+ pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
+ "Align read buffer size to max packet size to avoid the problem.\n",
+ data_len, ret);
+
+ return ret;
+}
+
+/*
+ * allocate a virtually contiguous buffer and create a scatterlist describing it
+ * @sg_table - pointer to a place to be filled with sg_table contents
+ * @size - required buffer size
+ */
+static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
+{
+ struct page **pages;
+ void *vaddr, *ptr;
+ unsigned int n_pages;
+ int i;
+
+ vaddr = vmalloc(sz);
+ if (!vaddr)
+ return NULL;
+
+ n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+ pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
+ if (!pages) {
+ vfree(vaddr);
+
+ return NULL;
+ }
+ for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
+ pages[i] = vmalloc_to_page(ptr);
+
+ if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
+ kvfree(pages);
+ vfree(vaddr);
+
+ return NULL;
+ }
+ kvfree(pages);
+
+ return vaddr;
+}
+
+static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
+ size_t data_len)
+{
+ if (io_data->use_sg)
+ return ffs_build_sg_list(&io_data->sgt, data_len);
+
+ return kmalloc(data_len, GFP_KERNEL);
+}
+
+static inline void ffs_free_buffer(struct ffs_io_data *io_data)
+{
+ if (!io_data->buf)
+ return;
+
+ if (io_data->use_sg) {
+ sg_free_table(&io_data->sgt);
+ vfree(io_data->buf);
+ } else {
+ kfree(io_data->buf);
+ }
+}
+
+static void ffs_user_copy_worker(struct work_struct *work)
+{
+ struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
+ work);
+ int ret = io_data->req->status ? io_data->req->status :
+ io_data->req->actual;
+ bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
+ unsigned long flags;
+
+ if (io_data->read && ret > 0) {
+ mm_segment_t oldfs = get_fs();
+
+ set_fs(USER_DS);
+ use_mm(io_data->mm);
+ ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
+ unuse_mm(io_data->mm);
+ set_fs(oldfs);
+ }
+
+ io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
+
+ if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
+ eventfd_signal(io_data->ffs->ffs_eventfd, 1);
+
+ spin_lock_irqsave(&io_data->ffs->eps_lock, flags);
+ usb_ep_free_request(io_data->ep, io_data->req);
+ io_data->req = NULL;
+ spin_unlock_irqrestore(&io_data->ffs->eps_lock, flags);
+
+ if (io_data->read)
+ kfree(io_data->to_free);
+ ffs_free_buffer(io_data);
+ kfree(io_data);
+}
+
+static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
+ struct usb_request *req)
+{
+ struct ffs_io_data *io_data = req->context;
+ struct ffs_data *ffs = io_data->ffs;
+
+ ENTER();
+
+ INIT_WORK(&io_data->work, ffs_user_copy_worker);
+ queue_work(ffs->io_completion_wq, &io_data->work);
+}
+
+static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
+{
+ /*
+ * See comment in struct ffs_epfile for full read_buffer pointer
+ * synchronisation story.
+ */
+ struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
+ if (buf && buf != READ_BUFFER_DROP)
+ kfree(buf);
+}
+
+/* Assumes epfile->mutex is held. */
+static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
+ struct iov_iter *iter)
+{
+ /*
+ * Null out epfile->read_buffer so ffs_func_eps_disable does not free
+ * the buffer while we are using it. See comment in struct ffs_epfile
+ * for full read_buffer pointer synchronisation story.
+ */
+ struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
+ ssize_t ret;
+ if (!buf || buf == READ_BUFFER_DROP)
+ return 0;
+
+ ret = copy_to_iter(buf->data, buf->length, iter);
+ if (buf->length == ret) {
+ kfree(buf);
+ return ret;
+ }
+
+ if (unlikely(iov_iter_count(iter))) {
+ ret = -EFAULT;
+ } else {
+ buf->length -= ret;
+ buf->data += ret;
+ }
+
+ if (cmpxchg(&epfile->read_buffer, NULL, buf))
+ kfree(buf);
+
+ return ret;
+}
+
+/* Assumes epfile->mutex is held. */
+static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
+ void *data, int data_len,
+ struct iov_iter *iter)
+{
+ struct ffs_buffer *buf;
+
+ ssize_t ret = copy_to_iter(data, data_len, iter);
+ if (likely(data_len == ret))
+ return ret;
+
+ if (unlikely(iov_iter_count(iter)))
+ return -EFAULT;
+
+ /* See ffs_copy_to_iter for more context. */
+ pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
+ data_len, ret);
+
+ data_len -= ret;
+ buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+ buf->length = data_len;
+ buf->data = buf->storage;
+ memcpy(buf->storage, data + ret, data_len);
+
+ /*
+ * At this point read_buffer is NULL or READ_BUFFER_DROP (if
+ * ffs_func_eps_disable has been called in the meanwhile). See comment
+ * in struct ffs_epfile for full read_buffer pointer synchronisation
+ * story.
+ */
+ if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
+ kfree(buf);
+
+ return ret;
+}
+
+static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
+{
+ struct ffs_epfile *epfile = file->private_data;
+ struct usb_request *req;
+ struct ffs_ep *ep;
+ char *data = NULL;
+ ssize_t ret, data_len = -EINVAL;
+ int halt;
+
+ /* Are we still active? */
+ if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
+ return -ENODEV;
+
+ /* Wait for endpoint to be enabled */
+ ep = epfile->ep;
+ if (!ep) {
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(
+ epfile->ffs->wait, (ep = epfile->ep));
+ if (ret)
+ return -EINTR;
+ }
+
+ /* Do we halt? */
+ halt = (!io_data->read == !epfile->in);
+ if (halt && epfile->isoc)
+ return -EINVAL;
+
+ /* We will be using request and read_buffer */
+ ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
+ if (unlikely(ret))
+ goto error;
+
+ /* Allocate & copy */
+ if (!halt) {
+ struct usb_gadget *gadget;
+
+ /*
+ * Do we have buffered data from previous partial read? Check
+ * that for synchronous case only because we do not have
+ * facility to ‘wake up’ a pending asynchronous read and push
+ * buffered data to it which we would need to make things behave
+ * consistently.
+ */
+ if (!io_data->aio && io_data->read) {
+ ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
+ if (ret)
+ goto error_mutex;
+ }
+
+ /*
+ * if we _do_ wait above, the epfile->ffs->gadget might be NULL
+ * before the waiting completes, so do not assign to 'gadget'
+ * earlier
+ */
+ gadget = epfile->ffs->gadget;
+
+ spin_lock_irq(&epfile->ffs->eps_lock);
+ /* In the meantime, endpoint got disabled or changed. */
+ if (epfile->ep != ep) {
+ ret = -ESHUTDOWN;
+ goto error_lock;
+ }
+ data_len = iov_iter_count(&io_data->data);
+ /*
+ * Controller may require buffer size to be aligned to
+ * maxpacketsize of an out endpoint.
+ */
+ if (io_data->read)
+ data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
+
+ io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
+ spin_unlock_irq(&epfile->ffs->eps_lock);
+
+ data = ffs_alloc_buffer(io_data, data_len);
+ if (unlikely(!data)) {
+ ret = -ENOMEM;
+ goto error_mutex;
+ }
+ if (!io_data->read &&
+ !copy_from_iter_full(data, data_len, &io_data->data)) {
+ ret = -EFAULT;
+ goto error_mutex;
+ }
+ }
+
+ spin_lock_irq(&epfile->ffs->eps_lock);
+
+ if (epfile->ep != ep) {
+ /* In the meantime, endpoint got disabled or changed. */
+ ret = -ESHUTDOWN;
+ } else if (halt) {
+ ret = usb_ep_set_halt(ep->ep);
+ if (!ret)
+ ret = -EBADMSG;
+ } else if (unlikely(data_len == -EINVAL)) {
+ /*
+ * Sanity Check: even though data_len can't be used
+ * uninitialized at the time I write this comment, some
+ * compilers complain about this situation.
+ * In order to keep the code clean from warnings, data_len is
+ * being initialized to -EINVAL during its declaration, which
+ * means we can't rely on compiler anymore to warn no future
+ * changes won't result in data_len being used uninitialized.
+ * For such reason, we're adding this redundant sanity check
+ * here.
+ */
+ WARN(1, "%s: data_len == -EINVAL\n", __func__);
+ ret = -EINVAL;
+ } else if (!io_data->aio) {
+ DECLARE_COMPLETION_ONSTACK(done);
+ bool interrupted = false;
+
+ req = ep->req;
+ if (io_data->use_sg) {
+ req->buf = NULL;
+ req->sg = io_data->sgt.sgl;
+ req->num_sgs = io_data->sgt.nents;
+ } else {
+ req->buf = data;
+ req->num_sgs = 0;
+ }
+ req->length = data_len;
+
+ io_data->buf = data;
+
+ req->context = &done;
+ req->complete = ffs_epfile_io_complete;
+
+ ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
+ if (unlikely(ret < 0))
+ goto error_lock;
+
+ spin_unlock_irq(&epfile->ffs->eps_lock);
+
+ if (unlikely(wait_for_completion_interruptible(&done))) {
+ /*
+ * To avoid race condition with ffs_epfile_io_complete,
+ * dequeue the request first then check
+ * status. usb_ep_dequeue API should guarantee no race
+ * condition with req->complete callback.
+ */
+ usb_ep_dequeue(ep->ep, req);
+ wait_for_completion(&done);
+ interrupted = ep->status < 0;
+ }
+
+ if (interrupted)
+ ret = -EINTR;
+ else if (io_data->read && ep->status > 0)
+ ret = __ffs_epfile_read_data(epfile, data, ep->status,
+ &io_data->data);
+ else
+ ret = ep->status;
+ goto error_mutex;
+ } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
+ ret = -ENOMEM;
+ } else {
+ if (io_data->use_sg) {
+ req->buf = NULL;
+ req->sg = io_data->sgt.sgl;
+ req->num_sgs = io_data->sgt.nents;
+ } else {
+ req->buf = data;
+ req->num_sgs = 0;
+ }
+ req->length = data_len;
+
+ io_data->buf = data;
+ io_data->ep = ep->ep;
+ io_data->req = req;
+ io_data->ffs = epfile->ffs;
+
+ req->context = io_data;
+ req->complete = ffs_epfile_async_io_complete;
+
+ ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
+ if (unlikely(ret)) {
+ io_data->req = NULL;
+ usb_ep_free_request(ep->ep, req);
+ goto error_lock;
+ }
+
+ ret = -EIOCBQUEUED;
+ /*
+ * Do not kfree the buffer in this function. It will be freed
+ * by ffs_user_copy_worker.
+ */
+ data = NULL;
+ }
+
+error_lock:
+ spin_unlock_irq(&epfile->ffs->eps_lock);
+error_mutex:
+ mutex_unlock(&epfile->mutex);
+error:
+ if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
+ ffs_free_buffer(io_data);
+ return ret;
+}
+
+static int
+ffs_epfile_open(struct inode *inode, struct file *file)
+{
+ struct ffs_epfile *epfile = inode->i_private;
+
+ ENTER();
+
+ if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
+ return -ENODEV;
+
+ file->private_data = epfile;
+ ffs_data_opened(epfile->ffs);
+
+ return stream_open(inode, file);
+}
+
+static int ffs_aio_cancel(struct kiocb *kiocb)
+{
+ struct ffs_io_data *io_data = kiocb->private;
+ struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
+ unsigned long flags;
+ int value;
+
+ ENTER();
+
+ spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
+
+ if (likely(io_data && io_data->ep && io_data->req))
+ value = usb_ep_dequeue(io_data->ep, io_data->req);
+ else
+ value = -EINVAL;
+
+ spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
+
+ return value;
+}
+
+static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
+{
+ struct ffs_io_data io_data, *p = &io_data;
+ ssize_t res;
+
+ ENTER();
+
+ if (!is_sync_kiocb(kiocb)) {
+ p = kzalloc(sizeof(io_data), GFP_KERNEL);
+ if (unlikely(!p))
+ return -ENOMEM;
+ p->aio = true;
+ } else {
+ memset(p, 0, sizeof(*p));
+ p->aio = false;
+ }
+
+ p->read = false;
+ p->kiocb = kiocb;
+ p->data = *from;
+ p->mm = current->mm;
+
+ kiocb->private = p;
+
+ if (p->aio)
+ kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
+
+ res = ffs_epfile_io(kiocb->ki_filp, p);
+ if (res == -EIOCBQUEUED)
+ return res;
+ if (p->aio)
+ kfree(p);
+ else
+ *from = p->data;
+ return res;
+}
+
+static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
+{
+ struct ffs_io_data io_data, *p = &io_data;
+ ssize_t res;
+
+ ENTER();
+
+ if (!is_sync_kiocb(kiocb)) {
+ p = kzalloc(sizeof(io_data), GFP_KERNEL);
+ if (unlikely(!p))
+ return -ENOMEM;
+ p->aio = true;
+ } else {
+ memset(p, 0, sizeof(*p));
+ p->aio = false;
+ }
+
+ p->read = true;
+ p->kiocb = kiocb;
+ if (p->aio) {
+ p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
+ if (!p->to_free) {
+ kfree(p);
+ return -ENOMEM;
+ }
+ } else {
+ p->data = *to;
+ p->to_free = NULL;
+ }
+ p->mm = current->mm;
+
+ kiocb->private = p;
+
+ if (p->aio)
+ kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
+
+ res = ffs_epfile_io(kiocb->ki_filp, p);
+ if (res == -EIOCBQUEUED)
+ return res;
+
+ if (p->aio) {
+ kfree(p->to_free);
+ kfree(p);
+ } else {
+ *to = p->data;
+ }
+ return res;
+}
+
+static int
+ffs_epfile_release(struct inode *inode, struct file *file)
+{
+ struct ffs_epfile *epfile = inode->i_private;
+
+ ENTER();
+
+ __ffs_epfile_read_buffer_free(epfile);
+ ffs_data_closed(epfile->ffs);
+
+ return 0;
+}
+
+static long ffs_epfile_ioctl(struct file *file, unsigned code,
+ unsigned long value)
+{
+ struct ffs_epfile *epfile = file->private_data;
+ struct ffs_ep *ep;
+ int ret;
+
+ ENTER();
+
+ if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
+ return -ENODEV;
+
+ /* Wait for endpoint to be enabled */
+ ep = epfile->ep;
+ if (!ep) {
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(
+ epfile->ffs->wait, (ep = epfile->ep));
+ if (ret)
+ return -EINTR;
+ }
+
+ spin_lock_irq(&epfile->ffs->eps_lock);
+
+ /* In the meantime, endpoint got disabled or changed. */
+ if (epfile->ep != ep) {
+ spin_unlock_irq(&epfile->ffs->eps_lock);
+ return -ESHUTDOWN;
+ }
+
+ switch (code) {
+ case FUNCTIONFS_FIFO_STATUS:
+ ret = usb_ep_fifo_status(epfile->ep->ep);
+ break;
+ case FUNCTIONFS_FIFO_FLUSH:
+ usb_ep_fifo_flush(epfile->ep->ep);
+ ret = 0;
+ break;
+ case FUNCTIONFS_CLEAR_HALT:
+ ret = usb_ep_clear_halt(epfile->ep->ep);
+ break;
+ case FUNCTIONFS_ENDPOINT_REVMAP:
+ ret = epfile->ep->num;
+ break;
+ case FUNCTIONFS_ENDPOINT_DESC:
+ {
+ int desc_idx;
+ struct usb_endpoint_descriptor desc1, *desc;
+
+ switch (epfile->ffs->gadget->speed) {
+ case USB_SPEED_SUPER:
+ case USB_SPEED_SUPER_PLUS:
+ desc_idx = 2;
+ break;
+ case USB_SPEED_HIGH:
+ desc_idx = 1;
+ break;
+ default:
+ desc_idx = 0;
+ }
+
+ desc = epfile->ep->descs[desc_idx];
+ memcpy(&desc1, desc, desc->bLength);
+
+ spin_unlock_irq(&epfile->ffs->eps_lock);
+ ret = copy_to_user((void __user *)value, &desc1, desc1.bLength);
+ if (ret)
+ ret = -EFAULT;
+ return ret;
+ }
+ default:
+ ret = -ENOTTY;
+ }
+ spin_unlock_irq(&epfile->ffs->eps_lock);
+
+ return ret;
+}
+
+#ifdef CONFIG_COMPAT
+static long ffs_epfile_compat_ioctl(struct file *file, unsigned code,
+ unsigned long value)
+{
+ return ffs_epfile_ioctl(file, code, value);
+}
+#endif
+
+static const struct file_operations ffs_epfile_operations = {
+ .llseek = no_llseek,
+
+ .open = ffs_epfile_open,
+ .write_iter = ffs_epfile_write_iter,
+ .read_iter = ffs_epfile_read_iter,
+ .release = ffs_epfile_release,
+ .unlocked_ioctl = ffs_epfile_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ffs_epfile_compat_ioctl,
+#endif
+};
+
+
+/* File system and super block operations ***********************************/
+
+/*
+ * Mounting the file system creates a controller file, used first for
+ * function configuration then later for event monitoring.
+ */
+
+static struct inode *__must_check
+ffs_sb_make_inode(struct super_block *sb, void *data,
+ const struct file_operations *fops,
+ const struct inode_operations *iops,
+ struct ffs_file_perms *perms)
+{
+ struct inode *inode;
+
+ ENTER();
+
+ inode = new_inode(sb);
+
+ if (likely(inode)) {
+ struct timespec64 ts = current_time(inode);
+
+ inode->i_ino = get_next_ino();
+ inode->i_mode = perms->mode;
+ inode->i_uid = perms->uid;
+ inode->i_gid = perms->gid;
+ inode->i_atime = ts;
+ inode->i_mtime = ts;
+ inode->i_ctime = ts;
+ inode->i_private = data;
+ if (fops)
+ inode->i_fop = fops;
+ if (iops)
+ inode->i_op = iops;
+ }
+
+ return inode;
+}
+
+/* Create "regular" file */
+static struct dentry *ffs_sb_create_file(struct super_block *sb,
+ const char *name, void *data,
+ const struct file_operations *fops)
+{
+ struct ffs_data *ffs = sb->s_fs_info;
+ struct dentry *dentry;
+ struct inode *inode;
+
+ ENTER();
+
+ dentry = d_alloc_name(sb->s_root, name);
+ if (unlikely(!dentry))
+ return NULL;
+
+ inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
+ if (unlikely(!inode)) {
+ dput(dentry);
+ return NULL;
+ }
+
+ d_add(dentry, inode);
+ return dentry;
+}
+
+/* Super block */
+static const struct super_operations ffs_sb_operations = {
+ .statfs = simple_statfs,
+ .drop_inode = generic_delete_inode,
+};
+
+struct ffs_sb_fill_data {
+ struct ffs_file_perms perms;
+ umode_t root_mode;
+ const char *dev_name;
+ bool no_disconnect;
+ struct ffs_data *ffs_data;
+};
+
+static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
+{
+ struct ffs_sb_fill_data *data = fc->fs_private;
+ struct inode *inode;
+ struct ffs_data *ffs = data->ffs_data;
+
+ ENTER();
+
+ ffs->sb = sb;
+ data->ffs_data = NULL;
+ sb->s_fs_info = ffs;
+ sb->s_blocksize = PAGE_SIZE;
+ sb->s_blocksize_bits = PAGE_SHIFT;
+ sb->s_magic = FUNCTIONFS_MAGIC;
+ sb->s_op = &ffs_sb_operations;
+ sb->s_time_gran = 1;
+
+ /* Root inode */
+ data->perms.mode = data->root_mode;
+ inode = ffs_sb_make_inode(sb, NULL,
+ &simple_dir_operations,
+ &simple_dir_inode_operations,
+ &data->perms);
+ sb->s_root = d_make_root(inode);
+ if (unlikely(!sb->s_root))
+ return -ENOMEM;
+
+ /* EP0 file */
+ if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
+ &ffs_ep0_operations)))
+ return -ENOMEM;
+
+ return 0;
+}
+
+enum {
+ Opt_no_disconnect,
+ Opt_rmode,
+ Opt_fmode,
+ Opt_mode,
+ Opt_uid,
+ Opt_gid,
+};
+
+static const struct fs_parameter_spec ffs_fs_param_specs[] = {
+ fsparam_bool ("no_disconnect", Opt_no_disconnect),
+ fsparam_u32 ("rmode", Opt_rmode),
+ fsparam_u32 ("fmode", Opt_fmode),
+ fsparam_u32 ("mode", Opt_mode),
+ fsparam_u32 ("uid", Opt_uid),
+ fsparam_u32 ("gid", Opt_gid),
+ {}
+};
+
+static const struct fs_parameter_description ffs_fs_fs_parameters = {
+ .name = "kAFS",
+ .specs = ffs_fs_param_specs,
+};
+
+static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+ struct ffs_sb_fill_data *data = fc->fs_private;
+ struct fs_parse_result result;
+ int opt;
+
+ ENTER();
+
+ opt = fs_parse(fc, &ffs_fs_fs_parameters, param, &result);
+ if (opt < 0)
+ return opt;
+
+ switch (opt) {
+ case Opt_no_disconnect:
+ data->no_disconnect = result.boolean;
+ break;
+ case Opt_rmode:
+ data->root_mode = (result.uint_32 & 0555) | S_IFDIR;
+ break;
+ case Opt_fmode:
+ data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
+ break;
+ case Opt_mode:
+ data->root_mode = (result.uint_32 & 0555) | S_IFDIR;
+ data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
+ break;
+
+ case Opt_uid:
+ data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
+ if (!uid_valid(data->perms.uid))
+ goto unmapped_value;
+ break;
+ case Opt_gid:
+ data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
+ if (!gid_valid(data->perms.gid))
+ goto unmapped_value;
+ break;
+
+ default:
+ return -ENOPARAM;
+ }
+
+ return 0;
+
+unmapped_value:
+ return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
+}
+
+/*
+ * Set up the superblock for a mount.
+ */
+static int ffs_fs_get_tree(struct fs_context *fc)
+{
+ struct ffs_sb_fill_data *ctx = fc->fs_private;
+ struct ffs_data *ffs;
+ int ret;
+
+ ENTER();
+
+ if (!fc->source)
+ return invalf(fc, "No source specified");
+
+ ffs = ffs_data_new(fc->source);
+ if (unlikely(!ffs))
+ return -ENOMEM;
+ ffs->file_perms = ctx->perms;
+ ffs->no_disconnect = ctx->no_disconnect;
+
+ ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
+ if (unlikely(!ffs->dev_name)) {
+ ffs_data_put(ffs);
+ return -ENOMEM;
+ }
+
+ ret = ffs_acquire_dev(ffs->dev_name, ffs);
+ if (ret) {
+ ffs_data_put(ffs);
+ return ret;
+ }
+
+ ctx->ffs_data = ffs;
+ return get_tree_nodev(fc, ffs_sb_fill);
+}
+
+static void ffs_fs_free_fc(struct fs_context *fc)
+{
+ struct ffs_sb_fill_data *ctx = fc->fs_private;
+
+ if (ctx) {
+ if (ctx->ffs_data) {
+ ffs_data_put(ctx->ffs_data);
+ }
+
+ kfree(ctx);
+ }
+}
+
+static const struct fs_context_operations ffs_fs_context_ops = {
+ .free = ffs_fs_free_fc,
+ .parse_param = ffs_fs_parse_param,
+ .get_tree = ffs_fs_get_tree,
+};
+
+static int ffs_fs_init_fs_context(struct fs_context *fc)
+{
+ struct ffs_sb_fill_data *ctx;
+
+ ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ ctx->perms.mode = S_IFREG | 0600;
+ ctx->perms.uid = GLOBAL_ROOT_UID;
+ ctx->perms.gid = GLOBAL_ROOT_GID;
+ ctx->root_mode = S_IFDIR | 0500;
+ ctx->no_disconnect = false;
+
+ fc->fs_private = ctx;
+ fc->ops = &ffs_fs_context_ops;
+ return 0;
+}
+
+static void
+ffs_fs_kill_sb(struct super_block *sb)
+{
+ ENTER();
+
+ kill_litter_super(sb);
+ if (sb->s_fs_info)
+ ffs_data_closed(sb->s_fs_info);
+}
+
+static struct file_system_type ffs_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "functionfs",
+ .init_fs_context = ffs_fs_init_fs_context,
+ .parameters = &ffs_fs_fs_parameters,
+ .kill_sb = ffs_fs_kill_sb,
+};
+MODULE_ALIAS_FS("functionfs");
+
+
+/* Driver's main init/cleanup functions *************************************/
+
+static int functionfs_init(void)
+{
+ int ret;
+
+ ENTER();
+
+ ret = register_filesystem(&ffs_fs_type);
+ if (likely(!ret))
+ pr_info("file system registered\n");
+ else
+ pr_err("failed registering file system (%d)\n", ret);
+
+ return ret;
+}
+
+static void functionfs_cleanup(void)
+{
+ ENTER();
+
+ pr_info("unloading\n");
+ unregister_filesystem(&ffs_fs_type);
+}
+
+
+/* ffs_data and ffs_function construction and destruction code **************/
+
+static void ffs_data_clear(struct ffs_data *ffs);
+static void ffs_data_reset(struct ffs_data *ffs);
+
+static void ffs_data_get(struct ffs_data *ffs)
+{
+ ENTER();
+
+ refcount_inc(&ffs->ref);
+}
+
+static void ffs_data_opened(struct ffs_data *ffs)
+{
+ ENTER();
+
+ refcount_inc(&ffs->ref);
+ if (atomic_add_return(1, &ffs->opened) == 1 &&
+ ffs->state == FFS_DEACTIVATED) {
+ ffs->state = FFS_CLOSING;
+ ffs_data_reset(ffs);
+ }
+}
+
+static void ffs_data_put(struct ffs_data *ffs)
+{
+ ENTER();
+
+ if (unlikely(refcount_dec_and_test(&ffs->ref))) {
+ pr_info("%s(): freeing\n", __func__);
+ ffs_data_clear(ffs);
+ ffs_release_dev(ffs->private_data);
+ BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
+ waitqueue_active(&ffs->ep0req_completion.wait) ||
+ waitqueue_active(&ffs->wait));
+ destroy_workqueue(ffs->io_completion_wq);
+ kfree(ffs->dev_name);
+ kfree(ffs);
+ }
+}
+
+static void ffs_data_closed(struct ffs_data *ffs)
+{
+ struct ffs_epfile *epfiles;
+ unsigned long flags;
+
+ ENTER();
+
+ if (atomic_dec_and_test(&ffs->opened)) {
+ if (ffs->no_disconnect) {
+ ffs->state = FFS_DEACTIVATED;
+ spin_lock_irqsave(&ffs->eps_lock, flags);
+ epfiles = ffs->epfiles;
+ ffs->epfiles = NULL;
+ spin_unlock_irqrestore(&ffs->eps_lock,
+ flags);
+
+ if (epfiles)
+ ffs_epfiles_destroy(epfiles,
+ ffs->eps_count);
+
+ if (ffs->setup_state == FFS_SETUP_PENDING)
+ __ffs_ep0_stall(ffs);
+ } else {
+ ffs->state = FFS_CLOSING;
+ ffs_data_reset(ffs);
+ }
+ }
+ if (atomic_read(&ffs->opened) < 0) {
+ ffs->state = FFS_CLOSING;
+ ffs_data_reset(ffs);
+ }
+
+ ffs_data_put(ffs);
+}
+
+static struct ffs_data *ffs_data_new(const char *dev_name)
+{
+ struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
+ if (unlikely(!ffs))
+ return NULL;
+
+ ENTER();
+
+ ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
+ if (!ffs->io_completion_wq) {
+ kfree(ffs);
+ return NULL;
+ }
+
+ refcount_set(&ffs->ref, 1);
+ atomic_set(&ffs->opened, 0);
+ ffs->state = FFS_READ_DESCRIPTORS;
+ mutex_init(&ffs->mutex);
+ spin_lock_init(&ffs->eps_lock);
+ init_waitqueue_head(&ffs->ev.waitq);
+ init_waitqueue_head(&ffs->wait);
+ init_completion(&ffs->ep0req_completion);
+
+ /* XXX REVISIT need to update it in some places, or do we? */
+ ffs->ev.can_stall = 1;
+
+ return ffs;
+}
+
+static void ffs_data_clear(struct ffs_data *ffs)
+{
+ struct ffs_epfile *epfiles;
+ unsigned long flags;
+
+ ENTER();
+
+ ffs_closed(ffs);
+
+ BUG_ON(ffs->gadget);
+
+ spin_lock_irqsave(&ffs->eps_lock, flags);
+ epfiles = ffs->epfiles;
+ ffs->epfiles = NULL;
+ spin_unlock_irqrestore(&ffs->eps_lock, flags);
+
+ /*
+ * potential race possible between ffs_func_eps_disable
+ * & ffs_epfile_release therefore maintaining a local
+ * copy of epfile will save us from use-after-free.
+ */
+ if (epfiles) {
+ ffs_epfiles_destroy(epfiles, ffs->eps_count);
+ ffs->epfiles = NULL;
+ }
+
+ if (ffs->ffs_eventfd) {
+ eventfd_ctx_put(ffs->ffs_eventfd);
+ ffs->ffs_eventfd = NULL;
+ }
+
+ kfree(ffs->raw_descs_data);
+ kfree(ffs->raw_strings);
+ kfree(ffs->stringtabs);
+}
+
+static void ffs_data_reset(struct ffs_data *ffs)
+{
+ ENTER();
+
+ ffs_data_clear(ffs);
+
+ ffs->raw_descs_data = NULL;
+ ffs->raw_descs = NULL;
+ ffs->raw_strings = NULL;
+ ffs->stringtabs = NULL;
+
+ ffs->raw_descs_length = 0;
+ ffs->fs_descs_count = 0;
+ ffs->hs_descs_count = 0;
+ ffs->ss_descs_count = 0;
+
+ ffs->strings_count = 0;
+ ffs->interfaces_count = 0;
+ ffs->eps_count = 0;
+
+ ffs->ev.count = 0;
+
+ ffs->state = FFS_READ_DESCRIPTORS;
+ ffs->setup_state = FFS_NO_SETUP;
+ ffs->flags = 0;
+
+ ffs->ms_os_descs_ext_prop_count = 0;
+ ffs->ms_os_descs_ext_prop_name_len = 0;
+ ffs->ms_os_descs_ext_prop_data_len = 0;
+}
+
+
+static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
+{
+ struct usb_gadget_strings **lang;
+ int first_id;
+
+ ENTER();
+
+ if ((ffs->state != FFS_ACTIVE
+ || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
+ return -EBADFD;
+
+ first_id = usb_string_ids_n(cdev, ffs->strings_count);
+ if (unlikely(first_id < 0))
+ return first_id;
+
+ ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
+ if (unlikely(!ffs->ep0req))
+ return -ENOMEM;
+ ffs->ep0req->complete = ffs_ep0_complete;
+ ffs->ep0req->context = ffs;
+
+ lang = ffs->stringtabs;
+ if (lang) {
+ for (; *lang; ++lang) {
+ struct usb_string *str = (*lang)->strings;
+ int id = first_id;
+ for (; str->s; ++id, ++str)
+ str->id = id;
+ }
+ }
+
+ ffs->gadget = cdev->gadget;
+ ffs_data_get(ffs);
+ return 0;
+}
+
+static void functionfs_unbind(struct ffs_data *ffs)
+{
+ ENTER();
+
+ if (!WARN_ON(!ffs->gadget)) {
+ /* dequeue before freeing ep0req */
+ usb_ep_dequeue(ffs->gadget->ep0, ffs->ep0req);
+ mutex_lock(&ffs->mutex);
+ usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
+ ffs->ep0req = NULL;
+ ffs->gadget = NULL;
+ clear_bit(FFS_FL_BOUND, &ffs->flags);
+ mutex_unlock(&ffs->mutex);
+ ffs_data_put(ffs);
+ }
+}
+
+static int ffs_epfiles_create(struct ffs_data *ffs)
+{
+ struct ffs_epfile *epfile, *epfiles;
+ unsigned i, count;
+
+ ENTER();
+
+ count = ffs->eps_count;
+ epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
+ if (!epfiles)
+ return -ENOMEM;
+
+ epfile = epfiles;
+ for (i = 1; i <= count; ++i, ++epfile) {
+ epfile->ffs = ffs;
+ mutex_init(&epfile->mutex);
+ if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
+ sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
+ else
+ sprintf(epfile->name, "ep%u", i);
+ epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
+ epfile,
+ &ffs_epfile_operations);
+ if (unlikely(!epfile->dentry)) {
+ ffs_epfiles_destroy(epfiles, i - 1);
+ return -ENOMEM;
+ }
+ }
+
+ ffs->epfiles = epfiles;
+ return 0;
+}
+
+static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
+{
+ struct ffs_epfile *epfile = epfiles;
+
+ ENTER();
+
+ for (; count; --count, ++epfile) {
+ BUG_ON(mutex_is_locked(&epfile->mutex));
+ if (epfile->dentry) {
+ d_delete(epfile->dentry);
+ dput(epfile->dentry);
+ epfile->dentry = NULL;
+ }
+ }
+
+ kfree(epfiles);
+}
+
+static void ffs_func_eps_disable(struct ffs_function *func)
+{
+ struct ffs_ep *ep;
+ struct ffs_epfile *epfile;
+ unsigned short count;
+ unsigned long flags;
+
+ spin_lock_irqsave(&func->ffs->eps_lock, flags);
+ count = func->ffs->eps_count;
+ epfile = func->ffs->epfiles;
+ ep = func->eps;
+ while (count--) {
+ /* pending requests get nuked */
+ if (likely(ep->ep))
+ usb_ep_disable(ep->ep);
+ ++ep;
+
+ if (epfile) {
+ epfile->ep = NULL;
+ __ffs_epfile_read_buffer_free(epfile);
+ ++epfile;
+ }
+ }
+ spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
+}
+
+static int ffs_func_eps_enable(struct ffs_function *func)
+{
+ struct ffs_data *ffs;
+ struct ffs_ep *ep;
+ struct ffs_epfile *epfile;
+ unsigned short count;
+ unsigned long flags;
+ int ret = 0;
+
+ spin_lock_irqsave(&func->ffs->eps_lock, flags);
+ ffs = func->ffs;
+ ep = func->eps;
+ epfile = ffs->epfiles;
+ count = ffs->eps_count;
+ while(count--) {
+ ep->ep->driver_data = ep;
+
+ ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
+ if (ret) {
+ pr_err("%s: config_ep_by_speed(%s) returned %d\n",
+ __func__, ep->ep->name, ret);
+ break;
+ }
+
+ ret = usb_ep_enable(ep->ep);
+ if (likely(!ret)) {
+ epfile->ep = ep;
+ epfile->in = usb_endpoint_dir_in(ep->ep->desc);
+ epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
+ } else {
+ break;
+ }
+
+ ++ep;
+ ++epfile;
+ }
+
+ wake_up_interruptible(&ffs->wait);
+ spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
+
+ return ret;
+}
+
+
+/* Parsing and building descriptors and strings *****************************/
+
+/*
+ * This validates if data pointed by data is a valid USB descriptor as
+ * well as record how many interfaces, endpoints and strings are
+ * required by given configuration. Returns address after the
+ * descriptor or NULL if data is invalid.
+ */
+
+enum ffs_entity_type {
+ FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
+};
+
+enum ffs_os_desc_type {
+ FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
+};
+
+typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
+ u8 *valuep,
+ struct usb_descriptor_header *desc,
+ void *priv);
+
+typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
+ struct usb_os_desc_header *h, void *data,
+ unsigned len, void *priv);
+
+static int __must_check ffs_do_single_desc(char *data, unsigned len,
+ ffs_entity_callback entity,
+ void *priv, int *current_class)
+{
+ struct usb_descriptor_header *_ds = (void *)data;
+ u8 length;
+ int ret;
+
+ ENTER();
+
+ /* At least two bytes are required: length and type */
+ if (len < 2) {
+ pr_vdebug("descriptor too short\n");
+ return -EINVAL;
+ }
+
+ /* If we have at least as many bytes as the descriptor takes? */
+ length = _ds->bLength;
+ if (len < length) {
+ pr_vdebug("descriptor longer then available data\n");
+ return -EINVAL;
+ }
+
+#define __entity_check_INTERFACE(val) 1
+#define __entity_check_STRING(val) (val)
+#define __entity_check_ENDPOINT(val) ((val) & USB_ENDPOINT_NUMBER_MASK)
+#define __entity(type, val) do { \
+ pr_vdebug("entity " #type "(%02x)\n", (val)); \
+ if (unlikely(!__entity_check_ ##type(val))) { \
+ pr_vdebug("invalid entity's value\n"); \
+ return -EINVAL; \
+ } \
+ ret = entity(FFS_ ##type, &val, _ds, priv); \
+ if (unlikely(ret < 0)) { \
+ pr_debug("entity " #type "(%02x); ret = %d\n", \
+ (val), ret); \
+ return ret; \
+ } \
+ } while (0)
+
+ /* Parse descriptor depending on type. */
+ switch (_ds->bDescriptorType) {
+ case USB_DT_DEVICE:
+ case USB_DT_CONFIG:
+ case USB_DT_STRING:
+ case USB_DT_DEVICE_QUALIFIER:
+ /* function can't have any of those */
+ pr_vdebug("descriptor reserved for gadget: %d\n",
+ _ds->bDescriptorType);
+ return -EINVAL;
+
+ case USB_DT_INTERFACE: {
+ struct usb_interface_descriptor *ds = (void *)_ds;
+ pr_vdebug("interface descriptor\n");
+ if (length != sizeof *ds)
+ goto inv_length;
+
+ __entity(INTERFACE, ds->bInterfaceNumber);
+ if (ds->iInterface)
+ __entity(STRING, ds->iInterface);
+ *current_class = ds->bInterfaceClass;
+ }
+ break;
+
+ case USB_DT_ENDPOINT: {
+ struct usb_endpoint_descriptor *ds = (void *)_ds;
+ pr_vdebug("endpoint descriptor\n");
+ if (length != USB_DT_ENDPOINT_SIZE &&
+ length != USB_DT_ENDPOINT_AUDIO_SIZE)
+ goto inv_length;
+ __entity(ENDPOINT, ds->bEndpointAddress);
+ }
+ break;
+
+ case USB_TYPE_CLASS | 0x01:
+ if (*current_class == USB_INTERFACE_CLASS_HID) {
+ pr_vdebug("hid descriptor\n");
+ if (length != sizeof(struct hid_descriptor))
+ goto inv_length;
+ break;
+ } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
+ pr_vdebug("ccid descriptor\n");
+ if (length != sizeof(struct ccid_descriptor))
+ goto inv_length;
+ break;
+ } else {
+ pr_vdebug("unknown descriptor: %d for class %d\n",
+ _ds->bDescriptorType, *current_class);
+ return -EINVAL;
+ }
+
+ case USB_DT_OTG:
+ if (length != sizeof(struct usb_otg_descriptor))
+ goto inv_length;
+ break;
+
+ case USB_DT_INTERFACE_ASSOCIATION: {
+ struct usb_interface_assoc_descriptor *ds = (void *)_ds;
+ pr_vdebug("interface association descriptor\n");
+ if (length != sizeof *ds)
+ goto inv_length;
+ if (ds->iFunction)
+ __entity(STRING, ds->iFunction);
+ }
+ break;
+
+ case USB_DT_SS_ENDPOINT_COMP:
+ pr_vdebug("EP SS companion descriptor\n");
+ if (length != sizeof(struct usb_ss_ep_comp_descriptor))
+ goto inv_length;
+ break;
+
+ case USB_DT_OTHER_SPEED_CONFIG:
+ case USB_DT_INTERFACE_POWER:
+ case USB_DT_DEBUG:
+ case USB_DT_SECURITY:
+ case USB_DT_CS_RADIO_CONTROL:
+ /* TODO */
+ pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
+ return -EINVAL;
+
+ default:
+ /* We should never be here */
+ pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
+ return -EINVAL;
+
+inv_length:
+ pr_vdebug("invalid length: %d (descriptor %d)\n",
+ _ds->bLength, _ds->bDescriptorType);
+ return -EINVAL;
+ }
+
+#undef __entity
+#undef __entity_check_DESCRIPTOR
+#undef __entity_check_INTERFACE
+#undef __entity_check_STRING
+#undef __entity_check_ENDPOINT
+
+ return length;
+}
+
+static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
+ ffs_entity_callback entity, void *priv)
+{
+ const unsigned _len = len;
+ unsigned long num = 0;
+ int current_class = -1;
+
+ ENTER();
+
+ for (;;) {
+ int ret;
+
+ if (num == count)
+ data = NULL;
+
+ /* Record "descriptor" entity */
+ ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
+ if (unlikely(ret < 0)) {
+ pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
+ num, ret);
+ return ret;
+ }
+
+ if (!data)
+ return _len - len;
+
+ ret = ffs_do_single_desc(data, len, entity, priv,
+ ¤t_class);
+ if (unlikely(ret < 0)) {
+ pr_debug("%s returns %d\n", __func__, ret);
+ return ret;
+ }
+
+ len -= ret;
+ data += ret;
+ ++num;
+ }
+}
+
+static int __ffs_data_do_entity(enum ffs_entity_type type,
+ u8 *valuep, struct usb_descriptor_header *desc,
+ void *priv)
+{
+ struct ffs_desc_helper *helper = priv;
+ struct usb_endpoint_descriptor *d;
+
+ ENTER();
+
+ switch (type) {
+ case FFS_DESCRIPTOR:
+ break;
+
+ case FFS_INTERFACE:
+ /*
+ * Interfaces are indexed from zero so if we
+ * encountered interface "n" then there are at least
+ * "n+1" interfaces.
+ */
+ if (*valuep >= helper->interfaces_count)
+ helper->interfaces_count = *valuep + 1;
+ break;
+
+ case FFS_STRING:
+ /*
+ * Strings are indexed from 1 (0 is reserved
+ * for languages list)
+ */
+ if (*valuep > helper->ffs->strings_count)
+ helper->ffs->strings_count = *valuep;
+ break;
+
+ case FFS_ENDPOINT:
+ d = (void *)desc;
+ helper->eps_count++;
+ if (helper->eps_count >= FFS_MAX_EPS_COUNT)
+ return -EINVAL;
+ /* Check if descriptors for any speed were already parsed */
+ if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
+ helper->ffs->eps_addrmap[helper->eps_count] =
+ d->bEndpointAddress;
+ else if (helper->ffs->eps_addrmap[helper->eps_count] !=
+ d->bEndpointAddress)
+ return -EINVAL;
+ break;
+ }
+
+ return 0;
+}
+
+static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
+ struct usb_os_desc_header *desc)
+{
+ u16 bcd_version = le16_to_cpu(desc->bcdVersion);
+ u16 w_index = le16_to_cpu(desc->wIndex);
+
+ if (bcd_version != 1) {
+ pr_vdebug("unsupported os descriptors version: %d",
+ bcd_version);
+ return -EINVAL;
+ }
+ switch (w_index) {
+ case 0x4:
+ *next_type = FFS_OS_DESC_EXT_COMPAT;
+ break;
+ case 0x5:
+ *next_type = FFS_OS_DESC_EXT_PROP;
+ break;
+ default:
+ pr_vdebug("unsupported os descriptor type: %d", w_index);
+ return -EINVAL;
+ }
+
+ return sizeof(*desc);
+}
+
+/*
+ * Process all extended compatibility/extended property descriptors
+ * of a feature descriptor
+ */
+static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
+ enum ffs_os_desc_type type,
+ u16 feature_count,
+ ffs_os_desc_callback entity,
+ void *priv,
+ struct usb_os_desc_header *h)
+{
+ int ret;
+ const unsigned _len = len;
+
+ ENTER();
+
+ /* loop over all ext compat/ext prop descriptors */
+ while (feature_count--) {
+ ret = entity(type, h, data, len, priv);
+ if (unlikely(ret < 0)) {
+ pr_debug("bad OS descriptor, type: %d\n", type);
+ return ret;
+ }
+ data += ret;
+ len -= ret;
+ }
+ return _len - len;
+}
+
+/* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
+static int __must_check ffs_do_os_descs(unsigned count,
+ char *data, unsigned len,
+ ffs_os_desc_callback entity, void *priv)
+{
+ const unsigned _len = len;
+ unsigned long num = 0;
+
+ ENTER();
+
+ for (num = 0; num < count; ++num) {
+ int ret;
+ enum ffs_os_desc_type type;
+ u16 feature_count;
+ struct usb_os_desc_header *desc = (void *)data;
+
+ if (len < sizeof(*desc))
+ return -EINVAL;
+
+ /*
+ * Record "descriptor" entity.
+ * Process dwLength, bcdVersion, wIndex, get b/wCount.
+ * Move the data pointer to the beginning of extended
+ * compatibilities proper or extended properties proper
+ * portions of the data
+ */
+ if (le32_to_cpu(desc->dwLength) > len)
+ return -EINVAL;
+
+ ret = __ffs_do_os_desc_header(&type, desc);
+ if (unlikely(ret < 0)) {
+ pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
+ num, ret);
+ return ret;
+ }
+ /*
+ * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
+ */
+ feature_count = le16_to_cpu(desc->wCount);
+ if (type == FFS_OS_DESC_EXT_COMPAT &&
+ (feature_count > 255 || desc->Reserved))
+ return -EINVAL;
+ len -= ret;
+ data += ret;
+
+ /*
+ * Process all function/property descriptors
+ * of this Feature Descriptor
+ */
+ ret = ffs_do_single_os_desc(data, len, type,
+ feature_count, entity, priv, desc);
+ if (unlikely(ret < 0)) {
+ pr_debug("%s returns %d\n", __func__, ret);
+ return ret;
+ }
+
+ len -= ret;
+ data += ret;
+ }
+ return _len - len;
+}
+
+/**
+ * Validate contents of the buffer from userspace related to OS descriptors.
+ */
+static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
+ struct usb_os_desc_header *h, void *data,
+ unsigned len, void *priv)
+{
+ struct ffs_data *ffs = priv;
+ u8 length;
+
+ ENTER();
+
+ switch (type) {
+ case FFS_OS_DESC_EXT_COMPAT: {
+ struct usb_ext_compat_desc *d = data;
+ int i;
+
+ if (len < sizeof(*d) ||
+ d->bFirstInterfaceNumber >= ffs->interfaces_count)
+ return -EINVAL;
+ if (d->Reserved1 != 1) {
+ /*
+ * According to the spec, Reserved1 must be set to 1
+ * but older kernels incorrectly rejected non-zero
+ * values. We fix it here to avoid returning EINVAL
+ * in response to values we used to accept.
+ */
+ pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
+ d->Reserved1 = 1;
+ }
+ for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
+ if (d->Reserved2[i])
+ return -EINVAL;
+
+ length = sizeof(struct usb_ext_compat_desc);
+ }
+ break;
+ case FFS_OS_DESC_EXT_PROP: {
+ struct usb_ext_prop_desc *d = data;
+ u32 type, pdl;
+ u16 pnl;
+
+ if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
+ return -EINVAL;
+ length = le32_to_cpu(d->dwSize);
+ if (len < length)
+ return -EINVAL;
+ type = le32_to_cpu(d->dwPropertyDataType);
+ if (type < USB_EXT_PROP_UNICODE ||
+ type > USB_EXT_PROP_UNICODE_MULTI) {
+ pr_vdebug("unsupported os descriptor property type: %d",
+ type);
+ return -EINVAL;
+ }
+ pnl = le16_to_cpu(d->wPropertyNameLength);
+ if (length < 14 + pnl) {
+ pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
+ length, pnl, type);
+ return -EINVAL;
+ }
+ pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
+ if (length != 14 + pnl + pdl) {
+ pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
+ length, pnl, pdl, type);
+ return -EINVAL;
+ }
+ ++ffs->ms_os_descs_ext_prop_count;
+ /* property name reported to the host as "WCHAR"s */
+ ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
+ ffs->ms_os_descs_ext_prop_data_len += pdl;
+ }
+ break;
+ default:
+ pr_vdebug("unknown descriptor: %d\n", type);
+ return -EINVAL;
+ }
+ return length;
+}
+
+static int __ffs_data_got_descs(struct ffs_data *ffs,
+ char *const _data, size_t len)
+{
+ char *data = _data, *raw_descs;
+ unsigned os_descs_count = 0, counts[3], flags;
+ int ret = -EINVAL, i;
+ struct ffs_desc_helper helper;
+
+ ENTER();
+
+ if (get_unaligned_le32(data + 4) != len)
+ goto error;
+
+ switch (get_unaligned_le32(data)) {
+ case FUNCTIONFS_DESCRIPTORS_MAGIC:
+ flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
+ data += 8;
+ len -= 8;
+ break;
+ case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
+ flags = get_unaligned_le32(data + 8);
+ ffs->user_flags = flags;
+ if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
+ FUNCTIONFS_HAS_HS_DESC |
+ FUNCTIONFS_HAS_SS_DESC |
+ FUNCTIONFS_HAS_MS_OS_DESC |
+ FUNCTIONFS_VIRTUAL_ADDR |
+ FUNCTIONFS_EVENTFD |
+ FUNCTIONFS_ALL_CTRL_RECIP |
+ FUNCTIONFS_CONFIG0_SETUP)) {
+ ret = -ENOSYS;
+ goto error;
+ }
+ data += 12;
+ len -= 12;
+ break;
+ default:
+ goto error;
+ }
+
+ if (flags & FUNCTIONFS_EVENTFD) {
+ if (len < 4)
+ goto error;
+ ffs->ffs_eventfd =
+ eventfd_ctx_fdget((int)get_unaligned_le32(data));
+ if (IS_ERR(ffs->ffs_eventfd)) {
+ ret = PTR_ERR(ffs->ffs_eventfd);
+ ffs->ffs_eventfd = NULL;
+ goto error;
+ }
+ data += 4;
+ len -= 4;
+ }
+
+ /* Read fs_count, hs_count and ss_count (if present) */
+ for (i = 0; i < 3; ++i) {
+ if (!(flags & (1 << i))) {
+ counts[i] = 0;
+ } else if (len < 4) {
+ goto error;
+ } else {
+ counts[i] = get_unaligned_le32(data);
+ data += 4;
+ len -= 4;
+ }
+ }
+ if (flags & (1 << i)) {
+ if (len < 4) {
+ goto error;
+ }
+ os_descs_count = get_unaligned_le32(data);
+ data += 4;
+ len -= 4;
+ };
+
+ /* Read descriptors */
+ raw_descs = data;
+ helper.ffs = ffs;
+ for (i = 0; i < 3; ++i) {
+ if (!counts[i])
+ continue;
+ helper.interfaces_count = 0;
+ helper.eps_count = 0;
+ ret = ffs_do_descs(counts[i], data, len,
+ __ffs_data_do_entity, &helper);
+ if (ret < 0)
+ goto error;
+ if (!ffs->eps_count && !ffs->interfaces_count) {
+ ffs->eps_count = helper.eps_count;
+ ffs->interfaces_count = helper.interfaces_count;
+ } else {
+ if (ffs->eps_count != helper.eps_count) {
+ ret = -EINVAL;
+ goto error;
+ }
+ if (ffs->interfaces_count != helper.interfaces_count) {
+ ret = -EINVAL;
+ goto error;
+ }
+ }
+ data += ret;
+ len -= ret;
+ }
+ if (os_descs_count) {
+ ret = ffs_do_os_descs(os_descs_count, data, len,
+ __ffs_data_do_os_desc, ffs);
+ if (ret < 0)
+ goto error;
+ data += ret;
+ len -= ret;
+ }
+
+ if (raw_descs == data || len) {
+ ret = -EINVAL;
+ goto error;
+ }
+
+ ffs->raw_descs_data = _data;
+ ffs->raw_descs = raw_descs;
+ ffs->raw_descs_length = data - raw_descs;
+ ffs->fs_descs_count = counts[0];
+ ffs->hs_descs_count = counts[1];
+ ffs->ss_descs_count = counts[2];
+ ffs->ms_os_descs_count = os_descs_count;
+
+ return 0;
+
+error:
+ kfree(_data);
+ return ret;
+}
+
+static int __ffs_data_got_strings(struct ffs_data *ffs,
+ char *const _data, size_t len)
+{
+ u32 str_count, needed_count, lang_count;
+ struct usb_gadget_strings **stringtabs, *t;
+ const char *data = _data;
+ struct usb_string *s;
+
+ ENTER();
+
+ if (unlikely(len < 16 ||
+ get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
+ get_unaligned_le32(data + 4) != len))
+ goto error;
+ str_count = get_unaligned_le32(data + 8);
+ lang_count = get_unaligned_le32(data + 12);
+
+ /* if one is zero the other must be zero */
+ if (unlikely(!str_count != !lang_count))
+ goto error;
+
+ /* Do we have at least as many strings as descriptors need? */
+ needed_count = ffs->strings_count;
+ if (unlikely(str_count < needed_count))
+ goto error;
+
+ /*
+ * If we don't need any strings just return and free all
+ * memory.
+ */
+ if (!needed_count) {
+ kfree(_data);
+ return 0;
+ }
+
+ /* Allocate everything in one chunk so there's less maintenance. */
+ {
+ unsigned i = 0;
+ vla_group(d);
+ vla_item(d, struct usb_gadget_strings *, stringtabs,
+ lang_count + 1);
+ vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
+ vla_item(d, struct usb_string, strings,
+ lang_count*(needed_count+1));
+
+ char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
+
+ if (unlikely(!vlabuf)) {
+ kfree(_data);
+ return -ENOMEM;
+ }
+
+ /* Initialize the VLA pointers */
+ stringtabs = vla_ptr(vlabuf, d, stringtabs);
+ t = vla_ptr(vlabuf, d, stringtab);
+ i = lang_count;
+ do {
+ *stringtabs++ = t++;
+ } while (--i);
+ *stringtabs = NULL;
+
+ /* stringtabs = vlabuf = d_stringtabs for later kfree */
+ stringtabs = vla_ptr(vlabuf, d, stringtabs);
+ t = vla_ptr(vlabuf, d, stringtab);
+ s = vla_ptr(vlabuf, d, strings);
+ }
+
+ /* For each language */
+ data += 16;
+ len -= 16;
+
+ do { /* lang_count > 0 so we can use do-while */
+ unsigned needed = needed_count;
+ u32 str_per_lang = str_count;
+
+ if (unlikely(len < 3))
+ goto error_free;
+ t->language = get_unaligned_le16(data);
+ t->strings = s;
+ ++t;
+
+ data += 2;
+ len -= 2;
+
+ /* For each string */
+ do { /* str_count > 0 so we can use do-while */
+ size_t length = strnlen(data, len);
+
+ if (unlikely(length == len))
+ goto error_free;
+
+ /*
+ * User may provide more strings then we need,
+ * if that's the case we simply ignore the
+ * rest
+ */
+ if (likely(needed)) {
+ /*
+ * s->id will be set while adding
+ * function to configuration so for
+ * now just leave garbage here.
+ */
+ s->s = data;
+ --needed;
+ ++s;
+ }
+
+ data += length + 1;
+ len -= length + 1;
+ } while (--str_per_lang);
+
+ s->id = 0; /* terminator */
+ s->s = NULL;
+ ++s;
+
+ } while (--lang_count);
+
+ /* Some garbage left? */
+ if (unlikely(len))
+ goto error_free;
+
+ /* Done! */
+ ffs->stringtabs = stringtabs;
+ ffs->raw_strings = _data;
+
+ return 0;
+
+error_free:
+ kfree(stringtabs);
+error:
+ kfree(_data);
+ return -EINVAL;
+}
+
+
+/* Events handling and management *******************************************/
+
+static void __ffs_event_add(struct ffs_data *ffs,
+ enum usb_functionfs_event_type type)
+{
+ enum usb_functionfs_event_type rem_type1, rem_type2 = type;
+ int neg = 0;
+
+ /*
+ * Abort any unhandled setup
+ *
+ * We do not need to worry about some cmpxchg() changing value
+ * of ffs->setup_state without holding the lock because when
+ * state is FFS_SETUP_PENDING cmpxchg() in several places in
+ * the source does nothing.
+ */
+ if (ffs->setup_state == FFS_SETUP_PENDING)
+ ffs->setup_state = FFS_SETUP_CANCELLED;
+
+ /*
+ * Logic of this function guarantees that there are at most four pending
+ * evens on ffs->ev.types queue. This is important because the queue
+ * has space for four elements only and __ffs_ep0_read_events function
+ * depends on that limit as well. If more event types are added, those
+ * limits have to be revisited or guaranteed to still hold.
+ */
+ switch (type) {
+ case FUNCTIONFS_RESUME:
+ rem_type2 = FUNCTIONFS_SUSPEND;
+ /* FALL THROUGH */
+ case FUNCTIONFS_SUSPEND:
+ case FUNCTIONFS_SETUP:
+ rem_type1 = type;
+ /* Discard all similar events */
+ break;
+
+ case FUNCTIONFS_BIND:
+ case FUNCTIONFS_UNBIND:
+ case FUNCTIONFS_DISABLE:
+ case FUNCTIONFS_ENABLE:
+ /* Discard everything other then power management. */
+ rem_type1 = FUNCTIONFS_SUSPEND;
+ rem_type2 = FUNCTIONFS_RESUME;
+ neg = 1;
+ break;
+
+ default:
+ WARN(1, "%d: unknown event, this should not happen\n", type);
+ return;
+ }
+
+ {
+ u8 *ev = ffs->ev.types, *out = ev;
+ unsigned n = ffs->ev.count;
+ for (; n; --n, ++ev)
+ if ((*ev == rem_type1 || *ev == rem_type2) == neg)
+ *out++ = *ev;
+ else
+ pr_vdebug("purging event %d\n", *ev);
+ ffs->ev.count = out - ffs->ev.types;
+ }
+
+ pr_vdebug("adding event %d\n", type);
+ ffs->ev.types[ffs->ev.count++] = type;
+ wake_up_locked(&ffs->ev.waitq);
+ if (ffs->ffs_eventfd)
+ eventfd_signal(ffs->ffs_eventfd, 1);
+}
+
+static void ffs_event_add(struct ffs_data *ffs,
+ enum usb_functionfs_event_type type)
+{
+ unsigned long flags;
+ spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
+ __ffs_event_add(ffs, type);
+ spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
+}
+
+/* Bind/unbind USB function hooks *******************************************/
+
+static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
+{
+ int i;
+
+ for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
+ if (ffs->eps_addrmap[i] == endpoint_address)
+ return i;
+ return -ENOENT;
+}
+
+static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
+ struct usb_descriptor_header *desc,
+ void *priv)
+{
+ struct usb_endpoint_descriptor *ds = (void *)desc;
+ struct ffs_function *func = priv;
+ struct ffs_ep *ffs_ep;
+ unsigned ep_desc_id;
+ int idx;
+ static const char *speed_names[] = { "full", "high", "super" };
+
+ if (type != FFS_DESCRIPTOR)
+ return 0;
+
+ /*
+ * If ss_descriptors is not NULL, we are reading super speed
+ * descriptors; if hs_descriptors is not NULL, we are reading high
+ * speed descriptors; otherwise, we are reading full speed
+ * descriptors.
+ */
+ if (func->function.ss_descriptors) {
+ ep_desc_id = 2;
+ func->function.ss_descriptors[(long)valuep] = desc;
+ } else if (func->function.hs_descriptors) {
+ ep_desc_id = 1;
+ func->function.hs_descriptors[(long)valuep] = desc;
+ } else {
+ ep_desc_id = 0;
+ func->function.fs_descriptors[(long)valuep] = desc;
+ }
+
+ if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
+ return 0;
+
+ idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
+ if (idx < 0)
+ return idx;
+
+ ffs_ep = func->eps + idx;
+
+ if (unlikely(ffs_ep->descs[ep_desc_id])) {
+ pr_err("two %sspeed descriptors for EP %d\n",
+ speed_names[ep_desc_id],
+ ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
+ return -EINVAL;
+ }
+ ffs_ep->descs[ep_desc_id] = ds;
+
+ ffs_dump_mem(": Original ep desc", ds, ds->bLength);
+ if (ffs_ep->ep) {
+ ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
+ if (!ds->wMaxPacketSize)
+ ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
+ } else {
+ struct usb_request *req;
+ struct usb_ep *ep;
+ u8 bEndpointAddress;
+ u16 wMaxPacketSize;
+
+ /*
+ * We back up bEndpointAddress because autoconfig overwrites
+ * it with physical endpoint address.
+ */
+ bEndpointAddress = ds->bEndpointAddress;
+ /*
+ * We back up wMaxPacketSize because autoconfig treats
+ * endpoint descriptors as if they were full speed.
+ */
+ wMaxPacketSize = ds->wMaxPacketSize;
+ pr_vdebug("autoconfig\n");
+ ep = usb_ep_autoconfig(func->gadget, ds);
+ if (unlikely(!ep))
+ return -ENOTSUPP;
+ ep->driver_data = func->eps + idx;
+
+ req = usb_ep_alloc_request(ep, GFP_KERNEL);
+ if (unlikely(!req))
+ return -ENOMEM;
+
+ ffs_ep->ep = ep;
+ ffs_ep->req = req;
+ func->eps_revmap[ds->bEndpointAddress &
+ USB_ENDPOINT_NUMBER_MASK] = idx + 1;
+ /*
+ * If we use virtual address mapping, we restore
+ * original bEndpointAddress value.
+ */
+ if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
+ ds->bEndpointAddress = bEndpointAddress;
+ /*
+ * Restore wMaxPacketSize which was potentially
+ * overwritten by autoconfig.
+ */
+ ds->wMaxPacketSize = wMaxPacketSize;
+ }
+ ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
+
+ return 0;
+}
+
+static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
+ struct usb_descriptor_header *desc,
+ void *priv)
+{
+ struct ffs_function *func = priv;
+ unsigned idx;
+ u8 newValue;
+
+ switch (type) {
+ default:
+ case FFS_DESCRIPTOR:
+ /* Handled in previous pass by __ffs_func_bind_do_descs() */
+ return 0;
+
+ case FFS_INTERFACE:
+ idx = *valuep;
+ if (func->interfaces_nums[idx] < 0) {
+ int id = usb_interface_id(func->conf, &func->function);
+ if (unlikely(id < 0))
+ return id;
+ func->interfaces_nums[idx] = id;
+ }
+ newValue = func->interfaces_nums[idx];
+ break;
+
+ case FFS_STRING:
+ /* String' IDs are allocated when fsf_data is bound to cdev */
+ newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
+ break;
+
+ case FFS_ENDPOINT:
+ /*
+ * USB_DT_ENDPOINT are handled in
+ * __ffs_func_bind_do_descs().
+ */
+ if (desc->bDescriptorType == USB_DT_ENDPOINT)
+ return 0;
+
+ idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
+ if (unlikely(!func->eps[idx].ep))
+ return -EINVAL;
+
+ {
+ struct usb_endpoint_descriptor **descs;
+ descs = func->eps[idx].descs;
+ newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
+ }
+ break;
+ }
+
+ pr_vdebug("%02x -> %02x\n", *valuep, newValue);
+ *valuep = newValue;
+ return 0;
+}
+
+static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
+ struct usb_os_desc_header *h, void *data,
+ unsigned len, void *priv)
+{
+ struct ffs_function *func = priv;
+ u8 length = 0;
+
+ switch (type) {
+ case FFS_OS_DESC_EXT_COMPAT: {
+ struct usb_ext_compat_desc *desc = data;
+ struct usb_os_desc_table *t;
+
+ t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
+ t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
+ memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
+ ARRAY_SIZE(desc->CompatibleID) +
+ ARRAY_SIZE(desc->SubCompatibleID));
+ length = sizeof(*desc);
+ }
+ break;
+ case FFS_OS_DESC_EXT_PROP: {
+ struct usb_ext_prop_desc *desc = data;
+ struct usb_os_desc_table *t;
+ struct usb_os_desc_ext_prop *ext_prop;
+ char *ext_prop_name;
+ char *ext_prop_data;
+
+ t = &func->function.os_desc_table[h->interface];
+ t->if_id = func->interfaces_nums[h->interface];
+
+ ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
+ func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
+
+ ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
+ ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
+ ext_prop->data_len = le32_to_cpu(*(__le32 *)
+ usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
+ length = ext_prop->name_len + ext_prop->data_len + 14;
+
+ ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
+ func->ffs->ms_os_descs_ext_prop_name_avail +=
+ ext_prop->name_len;
+
+ ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
+ func->ffs->ms_os_descs_ext_prop_data_avail +=
+ ext_prop->data_len;
+ memcpy(ext_prop_data,
+ usb_ext_prop_data_ptr(data, ext_prop->name_len),
+ ext_prop->data_len);
+ /* unicode data reported to the host as "WCHAR"s */
+ switch (ext_prop->type) {
+ case USB_EXT_PROP_UNICODE:
+ case USB_EXT_PROP_UNICODE_ENV:
+ case USB_EXT_PROP_UNICODE_LINK:
+ case USB_EXT_PROP_UNICODE_MULTI:
+ ext_prop->data_len *= 2;
+ break;
+ }
+ ext_prop->data = ext_prop_data;
+
+ memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
+ ext_prop->name_len);
+ /* property name reported to the host as "WCHAR"s */
+ ext_prop->name_len *= 2;
+ ext_prop->name = ext_prop_name;
+
+ t->os_desc->ext_prop_len +=
+ ext_prop->name_len + ext_prop->data_len + 14;
+ ++t->os_desc->ext_prop_count;
+ list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
+ }
+ break;
+ default:
+ pr_vdebug("unknown descriptor: %d\n", type);
+ }
+
+ return length;
+}
+
+static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
+ struct usb_configuration *c)
+{
+ struct ffs_function *func = ffs_func_from_usb(f);
+ struct f_fs_opts *ffs_opts =
+ container_of(f->fi, struct f_fs_opts, func_inst);
+ struct ffs_data *ffs_data;
+ int ret;
+
+ ENTER();
+
+ /*
+ * Legacy gadget triggers binding in functionfs_ready_callback,
+ * which already uses locking; taking the same lock here would
+ * cause a deadlock.
+ *
+ * Configfs-enabled gadgets however do need ffs_dev_lock.
+ */
+ if (!ffs_opts->no_configfs)
+ ffs_dev_lock();
+ ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
+ ffs_data = ffs_opts->dev->ffs_data;
+ if (!ffs_opts->no_configfs)
+ ffs_dev_unlock();
+ if (ret)
+ return ERR_PTR(ret);
+
+ func->ffs = ffs_data;
+ func->conf = c;
+ func->gadget = c->cdev->gadget;
+
+ /*
+ * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
+ * configurations are bound in sequence with list_for_each_entry,
+ * in each configuration its functions are bound in sequence
+ * with list_for_each_entry, so we assume no race condition
+ * with regard to ffs_opts->bound access
+ */
+ if (!ffs_opts->refcnt) {
+ ret = functionfs_bind(func->ffs, c->cdev);
+ if (ret)
+ return ERR_PTR(ret);
+ }
+ ffs_opts->refcnt++;
+ func->function.strings = func->ffs->stringtabs;
+
+ return ffs_opts;
+}
+
+static int _ffs_func_bind(struct usb_configuration *c,
+ struct usb_function *f)
+{
+ struct ffs_function *func = ffs_func_from_usb(f);
+ struct ffs_data *ffs = func->ffs;
+
+ const int full = !!func->ffs->fs_descs_count;
+ const int high = !!func->ffs->hs_descs_count;
+ const int super = !!func->ffs->ss_descs_count;
+
+ int fs_len, hs_len, ss_len, ret, i;
+ struct ffs_ep *eps_ptr;
+
+ /* Make it a single chunk, less management later on */
+ vla_group(d);
+ vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
+ vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
+ full ? ffs->fs_descs_count + 1 : 0);
+ vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
+ high ? ffs->hs_descs_count + 1 : 0);
+ vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
+ super ? ffs->ss_descs_count + 1 : 0);
+ vla_item_with_sz(d, short, inums, ffs->interfaces_count);
+ vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
+ c->cdev->use_os_string ? ffs->interfaces_count : 0);
+ vla_item_with_sz(d, char[16], ext_compat,
+ c->cdev->use_os_string ? ffs->interfaces_count : 0);
+ vla_item_with_sz(d, struct usb_os_desc, os_desc,
+ c->cdev->use_os_string ? ffs->interfaces_count : 0);
+ vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
+ ffs->ms_os_descs_ext_prop_count);
+ vla_item_with_sz(d, char, ext_prop_name,
+ ffs->ms_os_descs_ext_prop_name_len);
+ vla_item_with_sz(d, char, ext_prop_data,
+ ffs->ms_os_descs_ext_prop_data_len);
+ vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
+ char *vlabuf;
+
+ ENTER();
+
+ /* Has descriptors only for speeds gadget does not support */
+ if (unlikely(!(full | high | super)))
+ return -ENOTSUPP;
+
+ /* Allocate a single chunk, less management later on */
+ vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
+ if (unlikely(!vlabuf))
+ return -ENOMEM;
+
+ ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
+ ffs->ms_os_descs_ext_prop_name_avail =
+ vla_ptr(vlabuf, d, ext_prop_name);
+ ffs->ms_os_descs_ext_prop_data_avail =
+ vla_ptr(vlabuf, d, ext_prop_data);
+
+ /* Copy descriptors */
+ memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
+ ffs->raw_descs_length);
+
+ memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
+ eps_ptr = vla_ptr(vlabuf, d, eps);
+ for (i = 0; i < ffs->eps_count; i++)
+ eps_ptr[i].num = -1;
+
+ /* Save pointers
+ * d_eps == vlabuf, func->eps used to kfree vlabuf later
+ */
+ func->eps = vla_ptr(vlabuf, d, eps);
+ func->interfaces_nums = vla_ptr(vlabuf, d, inums);
+
+ /*
+ * Go through all the endpoint descriptors and allocate
+ * endpoints first, so that later we can rewrite the endpoint
+ * numbers without worrying that it may be described later on.
+ */
+ if (likely(full)) {
+ func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
+ fs_len = ffs_do_descs(ffs->fs_descs_count,
+ vla_ptr(vlabuf, d, raw_descs),
+ d_raw_descs__sz,
+ __ffs_func_bind_do_descs, func);
+ if (unlikely(fs_len < 0)) {
+ ret = fs_len;
+ goto error;
+ }
+ } else {
+ fs_len = 0;
+ }
+
+ if (likely(high)) {
+ func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
+ hs_len = ffs_do_descs(ffs->hs_descs_count,
+ vla_ptr(vlabuf, d, raw_descs) + fs_len,
+ d_raw_descs__sz - fs_len,
+ __ffs_func_bind_do_descs, func);
+ if (unlikely(hs_len < 0)) {
+ ret = hs_len;
+ goto error;
+ }
+ } else {
+ hs_len = 0;
+ }
+
+ if (likely(super)) {
+ func->function.ss_descriptors = func->function.ssp_descriptors =
+ vla_ptr(vlabuf, d, ss_descs);
+ ss_len = ffs_do_descs(ffs->ss_descs_count,
+ vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
+ d_raw_descs__sz - fs_len - hs_len,
+ __ffs_func_bind_do_descs, func);
+ if (unlikely(ss_len < 0)) {
+ ret = ss_len;
+ goto error;
+ }
+ } else {
+ ss_len = 0;
+ }
+
+ /*
+ * Now handle interface numbers allocation and interface and
+ * endpoint numbers rewriting. We can do that in one go
+ * now.
+ */
+ ret = ffs_do_descs(ffs->fs_descs_count +
+ (high ? ffs->hs_descs_count : 0) +
+ (super ? ffs->ss_descs_count : 0),
+ vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
+ __ffs_func_bind_do_nums, func);
+ if (unlikely(ret < 0))
+ goto error;
+
+ func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
+ if (c->cdev->use_os_string) {
+ for (i = 0; i < ffs->interfaces_count; ++i) {
+ struct usb_os_desc *desc;
+
+ desc = func->function.os_desc_table[i].os_desc =
+ vla_ptr(vlabuf, d, os_desc) +
+ i * sizeof(struct usb_os_desc);
+ desc->ext_compat_id =
+ vla_ptr(vlabuf, d, ext_compat) + i * 16;
+ INIT_LIST_HEAD(&desc->ext_prop);
+ }
+ ret = ffs_do_os_descs(ffs->ms_os_descs_count,
+ vla_ptr(vlabuf, d, raw_descs) +
+ fs_len + hs_len + ss_len,
+ d_raw_descs__sz - fs_len - hs_len -
+ ss_len,
+ __ffs_func_bind_do_os_desc, func);
+ if (unlikely(ret < 0))
+ goto error;
+ }
+ func->function.os_desc_n =
+ c->cdev->use_os_string ? ffs->interfaces_count : 0;
+
+ /* And we're done */
+ ffs_event_add(ffs, FUNCTIONFS_BIND);
+ return 0;
+
+error:
+ /* XXX Do we need to release all claimed endpoints here? */
+ return ret;
+}
+
+static int ffs_func_bind(struct usb_configuration *c,
+ struct usb_function *f)
+{
+ struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
+ struct ffs_function *func = ffs_func_from_usb(f);
+ int ret;
+
+ if (IS_ERR(ffs_opts))
+ return PTR_ERR(ffs_opts);
+
+ ret = _ffs_func_bind(c, f);
+ if (ret && !--ffs_opts->refcnt)
+ functionfs_unbind(func->ffs);
+
+ return ret;
+}
+
+
+/* Other USB function hooks *************************************************/
+
+static void ffs_reset_work(struct work_struct *work)
+{
+ struct ffs_data *ffs = container_of(work,
+ struct ffs_data, reset_work);
+ ffs_data_reset(ffs);
+}
+
+static int ffs_func_set_alt(struct usb_function *f,
+ unsigned interface, unsigned alt)
+{
+ struct ffs_function *func = ffs_func_from_usb(f);
+ struct ffs_data *ffs = func->ffs;
+ int ret = 0, intf;
+
+ if (alt != (unsigned)-1) {
+ intf = ffs_func_revmap_intf(func, interface);
+ if (unlikely(intf < 0))
+ return intf;
+ }
+
+ if (ffs->func)
+ ffs_func_eps_disable(ffs->func);
+
+ if (ffs->state == FFS_DEACTIVATED) {
+ ffs->state = FFS_CLOSING;
+ INIT_WORK(&ffs->reset_work, ffs_reset_work);
+ schedule_work(&ffs->reset_work);
+ return -ENODEV;
+ }
+
+ if (ffs->state != FFS_ACTIVE)
+ return -ENODEV;
+
+ if (alt == (unsigned)-1) {
+ ffs->func = NULL;
+ ffs_event_add(ffs, FUNCTIONFS_DISABLE);
+ return 0;
+ }
+
+ ffs->func = func;
+ ret = ffs_func_eps_enable(func);
+ if (likely(ret >= 0))
+ ffs_event_add(ffs, FUNCTIONFS_ENABLE);
+ return ret;
+}
+
+static void ffs_func_disable(struct usb_function *f)
+{
+ ffs_func_set_alt(f, 0, (unsigned)-1);
+}
+
+static int ffs_func_setup(struct usb_function *f,
+ const struct usb_ctrlrequest *creq)
+{
+ struct ffs_function *func = ffs_func_from_usb(f);
+ struct ffs_data *ffs = func->ffs;
+ unsigned long flags;
+ int ret;
+
+ ENTER();
+
+ pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
+ pr_vdebug("creq->bRequest = %02x\n", creq->bRequest);
+ pr_vdebug("creq->wValue = %04x\n", le16_to_cpu(creq->wValue));
+ pr_vdebug("creq->wIndex = %04x\n", le16_to_cpu(creq->wIndex));
+ pr_vdebug("creq->wLength = %04x\n", le16_to_cpu(creq->wLength));
+
+ /*
+ * Most requests directed to interface go through here
+ * (notable exceptions are set/get interface) so we need to
+ * handle them. All other either handled by composite or
+ * passed to usb_configuration->setup() (if one is set). No
+ * matter, we will handle requests directed to endpoint here
+ * as well (as it's straightforward). Other request recipient
+ * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
+ * is being used.
+ */
+ if (ffs->state != FFS_ACTIVE)
+ return -ENODEV;
+
+ switch (creq->bRequestType & USB_RECIP_MASK) {
+ case USB_RECIP_INTERFACE:
+ ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
+ if (unlikely(ret < 0))
+ return ret;
+ break;
+
+ case USB_RECIP_ENDPOINT:
+ ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
+ if (unlikely(ret < 0))
+ return ret;
+ if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
+ ret = func->ffs->eps_addrmap[ret];
+ break;
+
+ default:
+ if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
+ ret = le16_to_cpu(creq->wIndex);
+ else
+ return -EOPNOTSUPP;
+ }
+
+ spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
+ ffs->ev.setup = *creq;
+ ffs->ev.setup.wIndex = cpu_to_le16(ret);
+ __ffs_event_add(ffs, FUNCTIONFS_SETUP);
+ spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
+
+ return ffs->ev.setup.wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
+}
+
+static bool ffs_func_req_match(struct usb_function *f,
+ const struct usb_ctrlrequest *creq,
+ bool config0)
+{
+ struct ffs_function *func = ffs_func_from_usb(f);
+
+ if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
+ return false;
+
+ switch (creq->bRequestType & USB_RECIP_MASK) {
+ case USB_RECIP_INTERFACE:
+ return (ffs_func_revmap_intf(func,
+ le16_to_cpu(creq->wIndex)) >= 0);
+ case USB_RECIP_ENDPOINT:
+ return (ffs_func_revmap_ep(func,
+ le16_to_cpu(creq->wIndex)) >= 0);
+ default:
+ return (bool) (func->ffs->user_flags &
+ FUNCTIONFS_ALL_CTRL_RECIP);
+ }
+}
+
+static void ffs_func_suspend(struct usb_function *f)
+{
+ ENTER();
+ ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
+}
+
+static void ffs_func_resume(struct usb_function *f)
+{
+ ENTER();
+ ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
+}
+
+
+/* Endpoint and interface numbers reverse mapping ***************************/
+
+static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
+{
+ num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
+ return num ? num : -EDOM;
+}
+
+static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
+{
+ short *nums = func->interfaces_nums;
+ unsigned count = func->ffs->interfaces_count;
+
+ for (; count; --count, ++nums) {
+ if (*nums >= 0 && *nums == intf)
+ return nums - func->interfaces_nums;
+ }
+
+ return -EDOM;
+}
+
+
+/* Devices management *******************************************************/
+
+static LIST_HEAD(ffs_devices);
+
+static struct ffs_dev *_ffs_do_find_dev(const char *name)
+{
+ struct ffs_dev *dev;
+
+ if (!name)
+ return NULL;
+
+ list_for_each_entry(dev, &ffs_devices, entry) {
+ if (strcmp(dev->name, name) == 0)
+ return dev;
+ }
+
+ return NULL;
+}
+
+/*
+ * ffs_lock must be taken by the caller of this function
+ */
+static struct ffs_dev *_ffs_get_single_dev(void)
+{
+ struct ffs_dev *dev;
+
+ if (list_is_singular(&ffs_devices)) {
+ dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
+ if (dev->single)
+ return dev;
+ }
+
+ return NULL;
+}
+
+/*
+ * ffs_lock must be taken by the caller of this function
+ */
+static struct ffs_dev *_ffs_find_dev(const char *name)
+{
+ struct ffs_dev *dev;
+
+ dev = _ffs_get_single_dev();
+ if (dev)
+ return dev;
+
+ return _ffs_do_find_dev(name);
+}
+
+/* Configfs support *********************************************************/
+
+static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
+{
+ return container_of(to_config_group(item), struct f_fs_opts,
+ func_inst.group);
+}
+
+static void ffs_attr_release(struct config_item *item)
+{
+ struct f_fs_opts *opts = to_ffs_opts(item);
+
+ usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations ffs_item_ops = {
+ .release = ffs_attr_release,
+};
+
+static const struct config_item_type ffs_func_type = {
+ .ct_item_ops = &ffs_item_ops,
+ .ct_owner = THIS_MODULE,
+};
+
+
+/* Function registration interface ******************************************/
+
+static void ffs_free_inst(struct usb_function_instance *f)
+{
+ struct f_fs_opts *opts;
+
+ opts = to_f_fs_opts(f);
+ ffs_release_dev(opts->dev);
+ ffs_dev_lock();
+ _ffs_free_dev(opts->dev);
+ ffs_dev_unlock();
+ kfree(opts);
+}
+
+static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
+{
+ if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
+ return -ENAMETOOLONG;
+ return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
+}
+
+static struct usb_function_instance *ffs_alloc_inst(void)
+{
+ struct f_fs_opts *opts;
+ struct ffs_dev *dev;
+
+ opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+ if (!opts)
+ return ERR_PTR(-ENOMEM);
+
+ opts->func_inst.set_inst_name = ffs_set_inst_name;
+ opts->func_inst.free_func_inst = ffs_free_inst;
+ ffs_dev_lock();
+ dev = _ffs_alloc_dev();
+ ffs_dev_unlock();
+ if (IS_ERR(dev)) {
+ kfree(opts);
+ return ERR_CAST(dev);
+ }
+ opts->dev = dev;
+ dev->opts = opts;
+
+ config_group_init_type_name(&opts->func_inst.group, "",
+ &ffs_func_type);
+ return &opts->func_inst;
+}
+
+static void ffs_free(struct usb_function *f)
+{
+ kfree(ffs_func_from_usb(f));
+}
+
+static void ffs_func_unbind(struct usb_configuration *c,
+ struct usb_function *f)
+{
+ struct ffs_function *func = ffs_func_from_usb(f);
+ struct ffs_data *ffs = func->ffs;
+ struct f_fs_opts *opts =
+ container_of(f->fi, struct f_fs_opts, func_inst);
+ struct ffs_ep *ep = func->eps;
+ unsigned count = ffs->eps_count;
+ unsigned long flags;
+
+ ENTER();
+ if (ffs->func == func) {
+ ffs_func_eps_disable(func);
+ ffs->func = NULL;
+ }
+
+ /* Drain any pending AIO completions */
+ drain_workqueue(ffs->io_completion_wq);
+
+ ffs_event_add(ffs, FUNCTIONFS_UNBIND);
+ if (!--opts->refcnt)
+ functionfs_unbind(ffs);
+
+ /* cleanup after autoconfig */
+ spin_lock_irqsave(&func->ffs->eps_lock, flags);
+ while (count--) {
+ if (ep->ep && ep->req)
+ usb_ep_free_request(ep->ep, ep->req);
+ ep->req = NULL;
+ ++ep;
+ }
+ spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
+ kfree(func->eps);
+ func->eps = NULL;
+ /*
+ * eps, descriptors and interfaces_nums are allocated in the
+ * same chunk so only one free is required.
+ */
+ func->function.fs_descriptors = NULL;
+ func->function.hs_descriptors = NULL;
+ func->function.ss_descriptors = NULL;
+ func->function.ssp_descriptors = NULL;
+ func->interfaces_nums = NULL;
+
+}
+
+static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
+{
+ struct ffs_function *func;
+
+ ENTER();
+
+ func = kzalloc(sizeof(*func), GFP_KERNEL);
+ if (unlikely(!func))
+ return ERR_PTR(-ENOMEM);
+
+ func->function.name = "Function FS Gadget";
+
+ func->function.bind = ffs_func_bind;
+ func->function.unbind = ffs_func_unbind;
+ func->function.set_alt = ffs_func_set_alt;
+ func->function.disable = ffs_func_disable;
+ func->function.setup = ffs_func_setup;
+ func->function.req_match = ffs_func_req_match;
+ func->function.suspend = ffs_func_suspend;
+ func->function.resume = ffs_func_resume;
+ func->function.free_func = ffs_free;
+
+ return &func->function;
+}
+
+/*
+ * ffs_lock must be taken by the caller of this function
+ */
+static struct ffs_dev *_ffs_alloc_dev(void)
+{
+ struct ffs_dev *dev;
+ int ret;
+
+ if (_ffs_get_single_dev())
+ return ERR_PTR(-EBUSY);
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev)
+ return ERR_PTR(-ENOMEM);
+
+ if (list_empty(&ffs_devices)) {
+ ret = functionfs_init();
+ if (ret) {
+ kfree(dev);
+ return ERR_PTR(ret);
+ }
+ }
+
+ list_add(&dev->entry, &ffs_devices);
+
+ return dev;
+}
+
+int ffs_name_dev(struct ffs_dev *dev, const char *name)
+{
+ struct ffs_dev *existing;
+ int ret = 0;
+
+ ffs_dev_lock();
+
+ existing = _ffs_do_find_dev(name);
+ if (!existing)
+ strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
+ else if (existing != dev)
+ ret = -EBUSY;
+
+ ffs_dev_unlock();
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ffs_name_dev);
+
+int ffs_single_dev(struct ffs_dev *dev)
+{
+ int ret;
+
+ ret = 0;
+ ffs_dev_lock();
+
+ if (!list_is_singular(&ffs_devices))
+ ret = -EBUSY;
+ else
+ dev->single = true;
+
+ ffs_dev_unlock();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ffs_single_dev);
+
+/*
+ * ffs_lock must be taken by the caller of this function
+ */
+static void _ffs_free_dev(struct ffs_dev *dev)
+{
+ list_del(&dev->entry);
+
+ kfree(dev);
+ if (list_empty(&ffs_devices))
+ functionfs_cleanup();
+}
+
+static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data)
+{
+ int ret = 0;
+ struct ffs_dev *ffs_dev;
+
+ ENTER();
+ ffs_dev_lock();
+
+ ffs_dev = _ffs_find_dev(dev_name);
+ if (!ffs_dev) {
+ ret = -ENOENT;
+ } else if (ffs_dev->mounted) {
+ ret = -EBUSY;
+ } else if (ffs_dev->ffs_acquire_dev_callback &&
+ ffs_dev->ffs_acquire_dev_callback(ffs_dev)) {
+ ret = -ENOENT;
+ } else {
+ ffs_dev->mounted = true;
+ ffs_dev->ffs_data = ffs_data;
+ ffs_data->private_data = ffs_dev;
+ }
+
+ ffs_dev_unlock();
+ return ret;
+}
+
+static void ffs_release_dev(struct ffs_dev *ffs_dev)
+{
+ ENTER();
+ ffs_dev_lock();
+
+ if (ffs_dev && ffs_dev->mounted) {
+ ffs_dev->mounted = false;
+ if (ffs_dev->ffs_data) {
+ ffs_dev->ffs_data->private_data = NULL;
+ ffs_dev->ffs_data = NULL;
+ }
+
+ if (ffs_dev->ffs_release_dev_callback)
+ ffs_dev->ffs_release_dev_callback(ffs_dev);
+ }
+
+ ffs_dev_unlock();
+}
+
+static int ffs_ready(struct ffs_data *ffs)
+{
+ struct ffs_dev *ffs_obj;
+ int ret = 0;
+
+ ENTER();
+ ffs_dev_lock();
+
+ ffs_obj = ffs->private_data;
+ if (!ffs_obj) {
+ ret = -EINVAL;
+ goto done;
+ }
+ if (WARN_ON(ffs_obj->desc_ready)) {
+ ret = -EBUSY;
+ goto done;
+ }
+
+ ffs_obj->desc_ready = true;
+
+ if (ffs_obj->ffs_ready_callback) {
+ ret = ffs_obj->ffs_ready_callback(ffs);
+ if (ret)
+ goto done;
+ }
+
+ set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
+done:
+ ffs_dev_unlock();
+ return ret;
+}
+
+static void ffs_closed(struct ffs_data *ffs)
+{
+ struct ffs_dev *ffs_obj;
+ struct f_fs_opts *opts;
+ struct config_item *ci;
+
+ ENTER();
+ ffs_dev_lock();
+
+ ffs_obj = ffs->private_data;
+ if (!ffs_obj)
+ goto done;
+
+ ffs_obj->desc_ready = false;
+
+ if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
+ ffs_obj->ffs_closed_callback)
+ ffs_obj->ffs_closed_callback(ffs);
+
+ if (ffs_obj->opts)
+ opts = ffs_obj->opts;
+ else
+ goto done;
+
+ if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
+ || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
+ goto done;
+
+ ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
+ ffs_dev_unlock();
+
+ if (test_bit(FFS_FL_BOUND, &ffs->flags))
+ unregister_gadget_item(ci);
+ return;
+done:
+ ffs_dev_unlock();
+}
+
+/* Misc helper functions ****************************************************/
+
+static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
+{
+ return nonblock
+ ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
+ : mutex_lock_interruptible(mutex);
+}
+
+static char *ffs_prepare_buffer(const char __user *buf, size_t len)
+{
+ char *data;
+
+ if (unlikely(!len))
+ return NULL;
+
+ data = kmalloc(len, GFP_KERNEL);
+ if (unlikely(!data))
+ return ERR_PTR(-ENOMEM);
+
+ if (unlikely(copy_from_user(data, buf, len))) {
+ kfree(data);
+ return ERR_PTR(-EFAULT);
+ }
+
+ pr_vdebug("Buffer from user space:\n");
+ ffs_dump_mem("", data, len);
+
+ return data;
+}
+
+DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michal Nazarewicz");