diff options
Diffstat (limited to 'drivers/usb/gadget/function/f_fs.c')
| -rw-r--r-- | drivers/usb/gadget/function/f_fs.c | 3780 |
1 files changed, 3780 insertions, 0 deletions
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c new file mode 100644 index 000000000..49eb4e3c7 --- /dev/null +++ b/drivers/usb/gadget/function/f_fs.c @@ -0,0 +1,3780 @@ +// 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/hid.h> +#include <linux/module.h> +#include <linux/sched/signal.h> +#include <linux/uio.h> +#include <asm/unaligned.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 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; + + 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; +} + +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; + + 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); + + usb_ep_free_request(io_data->ep, io_data->req); + + if (io_data->read) + kfree(io_data->to_free); + kfree(io_data->buf); + 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); + spin_unlock_irq(&epfile->ffs->eps_lock); + + data = kmalloc(data_len, GFP_KERNEL); + 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; + req->buf = data; + req->length = data_len; + + 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 { + req->buf = data; + 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: + kfree(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, void *_data, int silent) +{ + struct ffs_sb_fill_data *data = _data; + 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; +} + +static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts) +{ + ENTER(); + + if (!opts || !*opts) + return 0; + + for (;;) { + unsigned long value; + char *eq, *comma; + + /* Option limit */ + comma = strchr(opts, ','); + if (comma) + *comma = 0; + + /* Value limit */ + eq = strchr(opts, '='); + if (unlikely(!eq)) { + pr_err("'=' missing in %s\n", opts); + return -EINVAL; + } + *eq = 0; + + /* Parse value */ + if (kstrtoul(eq + 1, 0, &value)) { + pr_err("%s: invalid value: %s\n", opts, eq + 1); + return -EINVAL; + } + + /* Interpret option */ + switch (eq - opts) { + case 13: + if (!memcmp(opts, "no_disconnect", 13)) + data->no_disconnect = !!value; + else + goto invalid; + break; + case 5: + if (!memcmp(opts, "rmode", 5)) + data->root_mode = (value & 0555) | S_IFDIR; + else if (!memcmp(opts, "fmode", 5)) + data->perms.mode = (value & 0666) | S_IFREG; + else + goto invalid; + break; + + case 4: + if (!memcmp(opts, "mode", 4)) { + data->root_mode = (value & 0555) | S_IFDIR; + data->perms.mode = (value & 0666) | S_IFREG; + } else { + goto invalid; + } + break; + + case 3: + if (!memcmp(opts, "uid", 3)) { + data->perms.uid = make_kuid(current_user_ns(), value); + if (!uid_valid(data->perms.uid)) { + pr_err("%s: unmapped value: %lu\n", opts, value); + return -EINVAL; + } + } else if (!memcmp(opts, "gid", 3)) { + data->perms.gid = make_kgid(current_user_ns(), value); + if (!gid_valid(data->perms.gid)) { + pr_err("%s: unmapped value: %lu\n", opts, value); + return -EINVAL; + } + } else { + goto invalid; + } + break; + + default: +invalid: + pr_err("%s: invalid option\n", opts); + return -EINVAL; + } + + /* Next iteration */ + if (!comma) + break; + opts = comma + 1; + } + + return 0; +} + +/* "mount -t functionfs dev_name /dev/function" ends up here */ + +static struct dentry * +ffs_fs_mount(struct file_system_type *t, int flags, + const char *dev_name, void *opts) +{ + struct ffs_sb_fill_data data = { + .perms = { + .mode = S_IFREG | 0600, + .uid = GLOBAL_ROOT_UID, + .gid = GLOBAL_ROOT_GID, + }, + .root_mode = S_IFDIR | 0500, + .no_disconnect = false, + }; + struct dentry *rv; + int ret; + struct ffs_data *ffs; + + ENTER(); + + ret = ffs_fs_parse_opts(&data, opts); + if (unlikely(ret < 0)) + return ERR_PTR(ret); + + ffs = ffs_data_new(dev_name); + if (unlikely(!ffs)) + return ERR_PTR(-ENOMEM); + ffs->file_perms = data.perms; + ffs->no_disconnect = data.no_disconnect; + + ffs->dev_name = kstrdup(dev_name, GFP_KERNEL); + if (unlikely(!ffs->dev_name)) { + ffs_data_put(ffs); + return ERR_PTR(-ENOMEM); + } + + ret = ffs_acquire_dev(dev_name, ffs); + if (ret) { + ffs_data_put(ffs); + return ERR_PTR(ret); + } + data.ffs_data = ffs; + + rv = mount_nodev(t, flags, &data, ffs_sb_fill); + if (IS_ERR(rv) && data.ffs_data) + ffs_data_put(data.ffs_data); + return rv; +} + +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", + .mount = ffs_fs_mount, + .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 (WARN_ON(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)) { + usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req); + ffs->ep0req = NULL; + ffs->gadget = NULL; + clear_bit(FFS_FL_BOUND, &ffs->flags); + 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) +{ + 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); + } + 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 HID_DT_HID: + pr_vdebug("hid descriptor\n"); + if (length != sizeof(struct hid_descriptor)) + goto inv_length; + break; + + 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; + + 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); + 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; + + /* + * We back up bEndpointAddress because autoconfig overwrites + * it with physical endpoint address. + */ + bEndpointAddress = ds->bEndpointAddress; + 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; + } + 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 creq->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); + + 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; + + ffs_event_add(ffs, FUNCTIONFS_UNBIND); +} + +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"); |