/* * f_fs.c -- user mode file system API for USB composite function controllers * * Copyright (C) 2010 Samsung Electronics * Author: Michal Nazarewicz * * Based on inode.c (GadgetFS) which was: * Copyright (C) 2003-2004 David Brownell * Copyright (C) 2003 Agilent Technologies * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ /* #define DEBUG */ /* #define VERBOSE_DEBUG */ #include #include #include #include #include #include #include #include #include #include #include #include "u_fs.h" #include "u_f.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(void) __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 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; wait_queue_head_t wait; struct ffs_data *ffs; struct ffs_ep *ep; /* P: ffs->eps_lock */ struct dentry *dentry; char name[5]; unsigned char in; /* P: ffs->eps_lock */ unsigned char isoc; /* P: ffs->eps_lock */ unsigned char _pad; }; /* ffs_io_data structure ***************************************************/ struct ffs_io_data { bool aio; bool read; struct kiocb *kiocb; const struct iovec *iovec; unsigned long nr_segs; char __user *buf; size_t len; struct mm_struct *mm; struct work_struct work; struct usb_ep *ep; struct usb_request *req; }; static int __must_check ffs_epfiles_create(struct ffs_data *ffs); static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count); static struct inode *__must_check ffs_sb_create_file(struct super_block *sb, const char *name, void *data, const struct file_operations *fops, struct dentry **dentry_p); /* 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 int _ffs_name_dev(struct ffs_dev *dev, const char *name); static void _ffs_free_dev(struct ffs_dev *dev); static void *ffs_acquire_dev(const char *dev_name); static void ffs_release_dev(struct ffs_data *ffs_data); 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_all(&ffs->ep0req_completion); } static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len) { 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; } set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags); 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; } static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf, size_t n) { /* * We are holding ffs->ev.waitq.lock and ffs->mutex and we need * to release them. */ struct usb_functionfs_event events[n]; unsigned i = 0; memset(events, 0, sizeof events); 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); if (n < ffs->ev.count) { ffs->ev.count -= n; memmove(ffs->ev.types, ffs->ev.types + n, ffs->ev.count * sizeof *ffs->ev.types); } else { ffs->ev.count = 0; } spin_unlock_irq(&ffs->ev.waitq.lock); mutex_unlock(&ffs->mutex); return unlikely(__copy_to_user(buf, events, sizeof events)) ? -EFAULT : sizeof events; } 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; } 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 0; } 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 unsigned int ffs_ep0_poll(struct file *file, poll_table *wait) { struct ffs_data *ffs = file->private_data; unsigned int mask = POLLWRNORM; 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 |= POLLOUT; break; case FFS_ACTIVE: switch (ffs->setup_state) { case FFS_NO_SETUP: if (ffs->ev.count) mask |= POLLIN; break; case FFS_SETUP_PENDING: case FFS_SETUP_CANCELLED: mask |= (POLLIN | POLLOUT); break; } case FFS_CLOSING: 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 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; if (io_data->read && ret > 0) { int i; size_t pos = 0; use_mm(io_data->mm); for (i = 0; i < io_data->nr_segs; i++) { if (unlikely(copy_to_user(io_data->iovec[i].iov_base, &io_data->buf[pos], io_data->iovec[i].iov_len))) { ret = -EFAULT; break; } pos += io_data->iovec[i].iov_len; } unuse_mm(io_data->mm); } aio_complete(io_data->kiocb, ret, ret); usb_ep_free_request(io_data->ep, io_data->req); io_data->kiocb->private = NULL; if (io_data->read) kfree(io_data->iovec); 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; ENTER(); INIT_WORK(&io_data->work, ffs_user_copy_worker); schedule_work(&io_data->work); } static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) { struct ffs_epfile *epfile = file->private_data; struct ffs_ep *ep; char *data = NULL; ssize_t ret, data_len; int halt; /* Are we still active? */ if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) { ret = -ENODEV; goto error; } /* Wait for endpoint to be enabled */ ep = epfile->ep; if (!ep) { if (file->f_flags & O_NONBLOCK) { ret = -EAGAIN; goto error; } ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep)); if (ret) { ret = -EINTR; goto error; } } /* Do we halt? */ halt = (!io_data->read == !epfile->in); if (halt && epfile->isoc) { ret = -EINVAL; goto error; } /* Allocate & copy */ if (!halt) { /* * if we _do_ wait above, the epfile->ffs->gadget might be NULL * before the waiting completes, so do not assign to 'gadget' earlier */ struct usb_gadget *gadget = epfile->ffs->gadget; /* * Controller may require buffer size to be aligned to * maxpacketsize of an out endpoint. */ data_len = io_data->read ? usb_ep_align_maybe(gadget, ep->ep, io_data->len) : io_data->len; data = kmalloc(data_len, GFP_KERNEL); if (unlikely(!data)) return -ENOMEM; if (io_data->aio && !io_data->read) { int i; size_t pos = 0; for (i = 0; i < io_data->nr_segs; i++) { if (unlikely(copy_from_user(&data[pos], io_data->iovec[i].iov_base, io_data->iovec[i].iov_len))) { ret = -EFAULT; goto error; } pos += io_data->iovec[i].iov_len; } } else { if (!io_data->read && unlikely(__copy_from_user(data, io_data->buf, io_data->len))) { ret = -EFAULT; goto error; } } } /* We will be using request */ ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK); if (unlikely(ret)) goto error; spin_lock_irq(&epfile->ffs->eps_lock); if (epfile->ep != ep) { /* In the meantime, endpoint got disabled or changed. */ ret = -ESHUTDOWN; spin_unlock_irq(&epfile->ffs->eps_lock); } else if (halt) { /* Halt */ if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep)) usb_ep_set_halt(ep->ep); spin_unlock_irq(&epfile->ffs->eps_lock); ret = -EBADMSG; } else { /* Fire the request */ struct usb_request *req; if (io_data->aio) { req = usb_ep_alloc_request(ep->ep, GFP_KERNEL); if (unlikely(!req)) goto error_lock; req->buf = data; req->length = io_data->len; io_data->buf = data; io_data->ep = ep->ep; io_data->req = req; req->context = io_data; req->complete = ffs_epfile_async_io_complete; ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC); if (unlikely(ret)) { usb_ep_free_request(ep->ep, req); goto error_lock; } ret = -EIOCBQUEUED; spin_unlock_irq(&epfile->ffs->eps_lock); } else { DECLARE_COMPLETION_ONSTACK(done); req = ep->req; req->buf = data; req->length = io_data->len; req->context = &done; req->complete = ffs_epfile_io_complete; ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC); spin_unlock_irq(&epfile->ffs->eps_lock); if (unlikely(ret < 0)) { /* nop */ } else if (unlikely( wait_for_completion_interruptible(&done))) { ret = -EINTR; usb_ep_dequeue(ep->ep, req); } else { /* * XXX We may end up silently droping data * here. Since data_len (i.e. req->length) may * be bigger than len (after being rounded up * to maxpacketsize), we may end up with more * data then user space has space for. */ ret = ep->status; if (io_data->read && ret > 0) { ret = min_t(size_t, ret, io_data->len); if (unlikely(copy_to_user(io_data->buf, data, ret))) ret = -EFAULT; } } kfree(data); } } mutex_unlock(&epfile->mutex); return ret; error_lock: spin_unlock_irq(&epfile->ffs->eps_lock); mutex_unlock(&epfile->mutex); error: kfree(data); return ret; } static ssize_t ffs_epfile_write(struct file *file, const char __user *buf, size_t len, loff_t *ptr) { struct ffs_io_data io_data; ENTER(); io_data.aio = false; io_data.read = false; io_data.buf = (char * __user)buf; io_data.len = len; return ffs_epfile_io(file, &io_data); } static ssize_t ffs_epfile_read(struct file *file, char __user *buf, size_t len, loff_t *ptr) { struct ffs_io_data io_data; ENTER(); io_data.aio = false; io_data.read = true; io_data.buf = buf; io_data.len = len; return ffs_epfile_io(file, &io_data); } 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 0; } 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; int value; ENTER(); spin_lock_irq(&epfile->ffs->eps_lock); 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_irq(&epfile->ffs->eps_lock); return value; } static ssize_t ffs_epfile_aio_write(struct kiocb *kiocb, const struct iovec *iovec, unsigned long nr_segs, loff_t loff) { struct ffs_io_data *io_data; ENTER(); io_data = kmalloc(sizeof(*io_data), GFP_KERNEL); if (unlikely(!io_data)) return -ENOMEM; io_data->aio = true; io_data->read = false; io_data->kiocb = kiocb; io_data->iovec = iovec; io_data->nr_segs = nr_segs; io_data->len = kiocb->ki_nbytes; io_data->mm = current->mm; kiocb->private = io_data; kiocb_set_cancel_fn(kiocb, ffs_aio_cancel); return ffs_epfile_io(kiocb->ki_filp, io_data); } static ssize_t ffs_epfile_aio_read(struct kiocb *kiocb, const struct iovec *iovec, unsigned long nr_segs, loff_t loff) { struct ffs_io_data *io_data; struct iovec *iovec_copy; ENTER(); iovec_copy = kmalloc_array(nr_segs, sizeof(*iovec_copy), GFP_KERNEL); if (unlikely(!iovec_copy)) return -ENOMEM; memcpy(iovec_copy, iovec, sizeof(struct iovec)*nr_segs); io_data = kmalloc(sizeof(*io_data), GFP_KERNEL); if (unlikely(!io_data)) { kfree(iovec_copy); return -ENOMEM; } io_data->aio = true; io_data->read = true; io_data->kiocb = kiocb; io_data->iovec = iovec_copy; io_data->nr_segs = nr_segs; io_data->len = kiocb->ki_nbytes; io_data->mm = current->mm; kiocb->private = io_data; kiocb_set_cancel_fn(kiocb, ffs_aio_cancel); return ffs_epfile_io(kiocb->ki_filp, io_data); } static int ffs_epfile_release(struct inode *inode, struct file *file) { struct ffs_epfile *epfile = inode->i_private; ENTER(); 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; int ret; ENTER(); if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) return -ENODEV; spin_lock_irq(&epfile->ffs->eps_lock); if (likely(epfile->ep)) { 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; default: ret = -ENOTTY; } } else { ret = -ENODEV; } spin_unlock_irq(&epfile->ffs->eps_lock); return ret; } static const struct file_operations ffs_epfile_operations = { .llseek = no_llseek, .open = ffs_epfile_open, .write = ffs_epfile_write, .read = ffs_epfile_read, .aio_write = ffs_epfile_aio_write, .aio_read = ffs_epfile_aio_read, .release = ffs_epfile_release, .unlocked_ioctl = ffs_epfile_ioctl, }; /* 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 timespec current_time = CURRENT_TIME; inode->i_ino = get_next_ino(); inode->i_mode = perms->mode; inode->i_uid = perms->uid; inode->i_gid = perms->gid; inode->i_atime = current_time; inode->i_mtime = current_time; inode->i_ctime = current_time; inode->i_private = data; if (fops) inode->i_fop = fops; if (iops) inode->i_op = iops; } return inode; } /* Create "regular" file */ static struct inode *ffs_sb_create_file(struct super_block *sb, const char *name, void *data, const struct file_operations *fops, struct dentry **dentry_p) { 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); if (dentry_p) *dentry_p = dentry; return inode; } /* 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; 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_CACHE_SIZE; sb->s_blocksize_bits = PAGE_CACHE_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, NULL))) 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 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, }; struct dentry *rv; int ret; void *ffs_dev; struct ffs_data *ffs; ENTER(); ret = ffs_fs_parse_opts(&data, opts); if (unlikely(ret < 0)) return ERR_PTR(ret); ffs = ffs_data_new(); if (unlikely(!ffs)) return ERR_PTR(-ENOMEM); ffs->file_perms = data.perms; ffs->dev_name = kstrdup(dev_name, GFP_KERNEL); if (unlikely(!ffs->dev_name)) { ffs_data_put(ffs); return ERR_PTR(-ENOMEM); } ffs_dev = ffs_acquire_dev(dev_name); if (IS_ERR(ffs_dev)) { ffs_data_put(ffs); return ERR_CAST(ffs_dev); } ffs->private_data = ffs_dev; data.ffs_data = ffs; rv = mount_nodev(t, flags, &data, ffs_sb_fill); if (IS_ERR(rv) && data.ffs_data) { ffs_release_dev(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_release_dev(sb->s_fs_info); ffs_data_put(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(); atomic_inc(&ffs->ref); } static void ffs_data_opened(struct ffs_data *ffs) { ENTER(); atomic_inc(&ffs->ref); atomic_inc(&ffs->opened); } static void ffs_data_put(struct ffs_data *ffs) { ENTER(); if (unlikely(atomic_dec_and_test(&ffs->ref))) { pr_info("%s(): freeing\n", __func__); ffs_data_clear(ffs); BUG_ON(waitqueue_active(&ffs->ev.waitq) || waitqueue_active(&ffs->ep0req_completion.wait)); kfree(ffs->dev_name); kfree(ffs); } } static void ffs_data_closed(struct ffs_data *ffs) { ENTER(); if (atomic_dec_and_test(&ffs->opened)) { ffs->state = FFS_CLOSING; ffs_data_reset(ffs); } ffs_data_put(ffs); } static struct ffs_data *ffs_data_new(void) { struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL); if (unlikely(!ffs)) return NULL; ENTER(); atomic_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_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) { ENTER(); if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags)) ffs_closed(ffs); BUG_ON(ffs->gadget); if (ffs->epfiles) ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count); 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->epfiles = NULL; 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; } 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; for (lang = ffs->stringtabs; *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); init_waitqueue_head(&epfile->wait); sprintf(epfiles->name, "ep%u", i); if (!unlikely(ffs_sb_create_file(ffs->sb, epfiles->name, epfile, &ffs_epfile_operations, &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) || waitqueue_active(&epfile->wait)); 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 = func->eps; struct ffs_epfile *epfile = func->ffs->epfiles; unsigned count = func->ffs->eps_count; unsigned long flags; spin_lock_irqsave(&func->ffs->eps_lock, flags); do { /* pending requests get nuked */ if (likely(ep->ep)) usb_ep_disable(ep->ep); epfile->ep = NULL; ++ep; ++epfile; } while (--count); spin_unlock_irqrestore(&func->ffs->eps_lock, flags); } static int ffs_func_eps_enable(struct ffs_function *func) { struct ffs_data *ffs = func->ffs; struct ffs_ep *ep = func->eps; struct ffs_epfile *epfile = ffs->epfiles; unsigned count = ffs->eps_count; unsigned long flags; int ret = 0; spin_lock_irqsave(&func->ffs->eps_lock, flags); do { struct usb_endpoint_descriptor *ds; int desc_idx; if (ffs->gadget->speed == USB_SPEED_SUPER) desc_idx = 2; else if (ffs->gadget->speed == USB_SPEED_HIGH) desc_idx = 1; else desc_idx = 0; /* fall-back to lower speed if desc missing for current speed */ do { ds = ep->descs[desc_idx]; } while (!ds && --desc_idx >= 0); if (!ds) { ret = -EINVAL; break; } ep->ep->driver_data = ep; ep->ep->desc = ds; ret = usb_ep_enable(ep->ep); if (likely(!ret)) { epfile->ep = ep; epfile->in = usb_endpoint_dir_in(ds); epfile->isoc = usb_endpoint_xfer_isoc(ds); } else { break; } wake_up(&epfile->wait); ++ep; ++epfile; } while (--count); 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 }; typedef int (*ffs_entity_callback)(enum ffs_entity_type entity, u8 *valuep, struct usb_descriptor_header *desc, void *priv); static int __must_check ffs_do_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_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_data *ffs = priv; 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 >= ffs->interfaces_count) ffs->interfaces_count = *valuep + 1; break; case FFS_STRING: /* * Strings are indexed from 1 (0 is magic ;) reserved * for languages list or some such) */ if (*valuep > ffs->strings_count) ffs->strings_count = *valuep; break; case FFS_ENDPOINT: /* Endpoints are indexed from 1 as well. */ if ((*valuep & USB_ENDPOINT_NUMBER_MASK) > ffs->eps_count) ffs->eps_count = (*valuep & USB_ENDPOINT_NUMBER_MASK); break; } return 0; } static int __ffs_data_got_descs(struct ffs_data *ffs, char *const _data, size_t len) { char *data = _data, *raw_descs; unsigned counts[3], flags; int ret = -EINVAL, i; 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); if (flags & ~(FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC | FUNCTIONFS_HAS_SS_DESC)) { ret = -ENOSYS; goto error; } data += 12; len -= 12; break; default: goto error; } /* 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; } } /* Read descriptors */ raw_descs = data; for (i = 0; i < 3; ++i) { if (!counts[i]) continue; ret = ffs_do_descs(counts[i], data, len, __ffs_data_do_entity, 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]; 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; struct usb_string *strings, *s; const char *data = _data; ENTER(); if (unlikely(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); strings = s; } /* For each language */ data += 16; len -= 16; do { /* lang_count > 0 so we can use do-while */ unsigned needed = needed_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_count); 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; 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: BUG(); } { 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); } 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_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, 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 = (ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK) - 1; 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; 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; } 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 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); 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; func->ffs = ffs_opts->dev->ffs_data; if (!ffs_opts->no_configfs) ffs_dev_unlock(); if (ret) return ERR_PTR(ret); func->conf = c; func->gadget = c->cdev->gadget; ffs_data_get(func->ffs); /* * 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 = gadget_is_dualspeed(func->gadget) && func->ffs->hs_descs_count; const int super = gadget_is_superspeed(func->gadget) && func->ffs->ss_descs_count; int fs_len, hs_len, ret; /* 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, 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 = kmalloc(vla_group_size(d), GFP_KERNEL); if (unlikely(!vlabuf)) return -ENOMEM; /* Zero */ memset(vla_ptr(vlabuf, d, eps), 0, d_eps__sz); /* 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); for (ret = ffs->eps_count; ret; --ret) { struct ffs_ep *ptr; ptr = vla_ptr(vlabuf, d, eps); ptr[ret].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 = vla_ptr(vlabuf, d, ss_descs); ret = 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(ret < 0)) goto error; } /* * 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; /* 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); if (IS_ERR(ffs_opts)) return PTR_ERR(ffs_opts); return _ffs_func_bind(c, f); } /* Other USB function hooks *************************************************/ 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_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) but what to do with any * other request? */ 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; break; default: 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 0; } 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; list_for_each_entry(dev, &ffs_devices, entry) { if (!dev->name || !name) continue; 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 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_dev_lock(); _ffs_free_dev(opts->dev); ffs_dev_unlock(); kfree(opts); } #define MAX_INST_NAME_LEN 40 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name) { struct f_fs_opts *opts; char *ptr; const char *tmp; int name_len, ret; name_len = strlen(name) + 1; if (name_len > MAX_INST_NAME_LEN) return -ENAMETOOLONG; ptr = kstrndup(name, name_len, GFP_KERNEL); if (!ptr) return -ENOMEM; opts = to_f_fs_opts(fi); tmp = NULL; ffs_dev_lock(); tmp = opts->dev->name_allocated ? opts->dev->name : NULL; ret = _ffs_name_dev(opts->dev, ptr); if (ret) { kfree(ptr); ffs_dev_unlock(); return ret; } opts->dev->name_allocated = true; ffs_dev_unlock(); kfree(tmp); return 0; } 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; } if (!--opts->refcnt) functionfs_unbind(ffs); /* cleanup after autoconfig */ spin_lock_irqsave(&func->ffs->eps_lock, flags); do { if (ep->ep && ep->req) usb_ep_free_request(ep->ep, ep->req); ep->req = NULL; ++ep; } while (--count); 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->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.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; } /* * ffs_lock must be taken by the caller of this function * The caller is responsible for "name" being available whenever f_fs needs it */ static int _ffs_name_dev(struct ffs_dev *dev, const char *name) { struct ffs_dev *existing; existing = _ffs_do_find_dev(name); if (existing) return -EBUSY; dev->name = name; return 0; } /* * The caller is responsible for "name" being available whenever f_fs needs it */ int ffs_name_dev(struct ffs_dev *dev, const char *name) { int ret; ffs_dev_lock(); ret = _ffs_name_dev(dev, name); 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); if (dev->name_allocated) kfree(dev->name); kfree(dev); if (list_empty(&ffs_devices)) functionfs_cleanup(); } static void *ffs_acquire_dev(const char *dev_name) { struct ffs_dev *ffs_dev; ENTER(); ffs_dev_lock(); ffs_dev = _ffs_find_dev(dev_name); if (!ffs_dev) ffs_dev = ERR_PTR(-ENODEV); else if (ffs_dev->mounted) ffs_dev = ERR_PTR(-EBUSY); else if (ffs_dev->ffs_acquire_dev_callback && ffs_dev->ffs_acquire_dev_callback(ffs_dev)) ffs_dev = ERR_PTR(-ENODEV); else ffs_dev->mounted = true; ffs_dev_unlock(); return ffs_dev; } static void ffs_release_dev(struct ffs_data *ffs_data) { struct ffs_dev *ffs_dev; ENTER(); ffs_dev_lock(); ffs_dev = ffs_data->private_data; if (ffs_dev) { ffs_dev->mounted = false; 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; ffs_obj->ffs_data = ffs; if (ffs_obj->ffs_ready_callback) ret = ffs_obj->ffs_ready_callback(ffs); done: ffs_dev_unlock(); return ret; } static void ffs_closed(struct ffs_data *ffs) { struct ffs_dev *ffs_obj; ENTER(); ffs_dev_lock(); ffs_obj = ffs->private_data; if (!ffs_obj) goto done; ffs_obj->desc_ready = false; if (ffs_obj->ffs_closed_callback) ffs_obj->ffs_closed_callback(ffs); if (!ffs_obj->opts || ffs_obj->opts->no_configfs || !ffs_obj->opts->func_inst.group.cg_item.ci_parent) goto done; unregister_gadget_item(ffs_obj->opts-> func_inst.group.cg_item.ci_parent->ci_parent); 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");