diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/usb/gadget/legacy/inode.c | 2137 |
1 files changed, 2137 insertions, 0 deletions
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c new file mode 100644 index 000000000..d605bc2e7 --- /dev/null +++ b/drivers/usb/gadget/legacy/inode.c @@ -0,0 +1,2137 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * inode.c -- user mode filesystem api for usb gadget controllers + * + * Copyright (C) 2003-2004 David Brownell + * Copyright (C) 2003 Agilent Technologies + */ + + +/* #define VERBOSE_DEBUG */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/fs_context.h> +#include <linux/pagemap.h> +#include <linux/uts.h> +#include <linux/wait.h> +#include <linux/compiler.h> +#include <linux/uaccess.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/poll.h> +#include <linux/kthread.h> +#include <linux/aio.h> +#include <linux/uio.h> +#include <linux/refcount.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/moduleparam.h> + +#include <linux/usb/gadgetfs.h> +#include <linux/usb/gadget.h> + + +/* + * The gadgetfs API maps each endpoint to a file descriptor so that you + * can use standard synchronous read/write calls for I/O. There's some + * O_NONBLOCK and O_ASYNC/FASYNC style i/o support. Example usermode + * drivers show how this works in practice. You can also use AIO to + * eliminate I/O gaps between requests, to help when streaming data. + * + * Key parts that must be USB-specific are protocols defining how the + * read/write operations relate to the hardware state machines. There + * are two types of files. One type is for the device, implementing ep0. + * The other type is for each IN or OUT endpoint. In both cases, the + * user mode driver must configure the hardware before using it. + * + * - First, dev_config() is called when /dev/gadget/$CHIP is configured + * (by writing configuration and device descriptors). Afterwards it + * may serve as a source of device events, used to handle all control + * requests other than basic enumeration. + * + * - Then, after a SET_CONFIGURATION control request, ep_config() is + * called when each /dev/gadget/ep* file is configured (by writing + * endpoint descriptors). Afterwards these files are used to write() + * IN data or to read() OUT data. To halt the endpoint, a "wrong + * direction" request is issued (like reading an IN endpoint). + * + * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe + * not possible on all hardware. For example, precise fault handling with + * respect to data left in endpoint fifos after aborted operations; or + * selective clearing of endpoint halts, to implement SET_INTERFACE. + */ + +#define DRIVER_DESC "USB Gadget filesystem" +#define DRIVER_VERSION "24 Aug 2004" + +static const char driver_desc [] = DRIVER_DESC; +static const char shortname [] = "gadgetfs"; + +MODULE_DESCRIPTION (DRIVER_DESC); +MODULE_AUTHOR ("David Brownell"); +MODULE_LICENSE ("GPL"); + +static int ep_open(struct inode *, struct file *); + + +/*----------------------------------------------------------------------*/ + +#define GADGETFS_MAGIC 0xaee71ee7 + +/* /dev/gadget/$CHIP represents ep0 and the whole device */ +enum ep0_state { + /* DISABLED is the initial state. */ + STATE_DEV_DISABLED = 0, + + /* Only one open() of /dev/gadget/$CHIP; only one file tracks + * ep0/device i/o modes and binding to the controller. Driver + * must always write descriptors to initialize the device, then + * the device becomes UNCONNECTED until enumeration. + */ + STATE_DEV_OPENED, + + /* From then on, ep0 fd is in either of two basic modes: + * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it + * - SETUP: read/write will transfer control data and succeed; + * or if "wrong direction", performs protocol stall + */ + STATE_DEV_UNCONNECTED, + STATE_DEV_CONNECTED, + STATE_DEV_SETUP, + + /* UNBOUND means the driver closed ep0, so the device won't be + * accessible again (DEV_DISABLED) until all fds are closed. + */ + STATE_DEV_UNBOUND, +}; + +/* enough for the whole queue: most events invalidate others */ +#define N_EVENT 5 + +#define RBUF_SIZE 256 + +struct dev_data { + spinlock_t lock; + refcount_t count; + int udc_usage; + enum ep0_state state; /* P: lock */ + struct usb_gadgetfs_event event [N_EVENT]; + unsigned ev_next; + struct fasync_struct *fasync; + u8 current_config; + + /* drivers reading ep0 MUST handle control requests (SETUP) + * reported that way; else the host will time out. + */ + unsigned usermode_setup : 1, + setup_in : 1, + setup_can_stall : 1, + setup_out_ready : 1, + setup_out_error : 1, + setup_abort : 1, + gadget_registered : 1; + unsigned setup_wLength; + + /* the rest is basically write-once */ + struct usb_config_descriptor *config, *hs_config; + struct usb_device_descriptor *dev; + struct usb_request *req; + struct usb_gadget *gadget; + struct list_head epfiles; + void *buf; + wait_queue_head_t wait; + struct super_block *sb; + struct dentry *dentry; + + /* except this scratch i/o buffer for ep0 */ + u8 rbuf[RBUF_SIZE]; +}; + +static inline void get_dev (struct dev_data *data) +{ + refcount_inc (&data->count); +} + +static void put_dev (struct dev_data *data) +{ + if (likely (!refcount_dec_and_test (&data->count))) + return; + /* needs no more cleanup */ + BUG_ON (waitqueue_active (&data->wait)); + kfree (data); +} + +static struct dev_data *dev_new (void) +{ + struct dev_data *dev; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) + return NULL; + dev->state = STATE_DEV_DISABLED; + refcount_set (&dev->count, 1); + spin_lock_init (&dev->lock); + INIT_LIST_HEAD (&dev->epfiles); + init_waitqueue_head (&dev->wait); + return dev; +} + +/*----------------------------------------------------------------------*/ + +/* other /dev/gadget/$ENDPOINT files represent endpoints */ +enum ep_state { + STATE_EP_DISABLED = 0, + STATE_EP_READY, + STATE_EP_ENABLED, + STATE_EP_UNBOUND, +}; + +struct ep_data { + struct mutex lock; + enum ep_state state; + refcount_t count; + struct dev_data *dev; + /* must hold dev->lock before accessing ep or req */ + struct usb_ep *ep; + struct usb_request *req; + ssize_t status; + char name [16]; + struct usb_endpoint_descriptor desc, hs_desc; + struct list_head epfiles; + wait_queue_head_t wait; + struct dentry *dentry; +}; + +static inline void get_ep (struct ep_data *data) +{ + refcount_inc (&data->count); +} + +static void put_ep (struct ep_data *data) +{ + if (likely (!refcount_dec_and_test (&data->count))) + return; + put_dev (data->dev); + /* needs no more cleanup */ + BUG_ON (!list_empty (&data->epfiles)); + BUG_ON (waitqueue_active (&data->wait)); + kfree (data); +} + +/*----------------------------------------------------------------------*/ + +/* most "how to use the hardware" policy choices are in userspace: + * mapping endpoint roles (which the driver needs) to the capabilities + * which the usb controller has. most of those capabilities are exposed + * implicitly, starting with the driver name and then endpoint names. + */ + +static const char *CHIP; +static DEFINE_MUTEX(sb_mutex); /* Serialize superblock operations */ + +/*----------------------------------------------------------------------*/ + +/* NOTE: don't use dev_printk calls before binding to the gadget + * at the end of ep0 configuration, or after unbind. + */ + +/* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */ +#define xprintk(d,level,fmt,args...) \ + printk(level "%s: " fmt , shortname , ## args) + +#ifdef DEBUG +#define DBG(dev,fmt,args...) \ + xprintk(dev , KERN_DEBUG , fmt , ## args) +#else +#define DBG(dev,fmt,args...) \ + do { } while (0) +#endif /* DEBUG */ + +#ifdef VERBOSE_DEBUG +#define VDEBUG DBG +#else +#define VDEBUG(dev,fmt,args...) \ + do { } while (0) +#endif /* DEBUG */ + +#define ERROR(dev,fmt,args...) \ + xprintk(dev , KERN_ERR , fmt , ## args) +#define INFO(dev,fmt,args...) \ + xprintk(dev , KERN_INFO , fmt , ## args) + + +/*----------------------------------------------------------------------*/ + +/* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso) + * + * After opening, configure non-control endpoints. Then use normal + * stream read() and write() requests; and maybe ioctl() to get more + * precise FIFO status when recovering from cancellation. + */ + +static void epio_complete (struct usb_ep *ep, struct usb_request *req) +{ + struct ep_data *epdata = ep->driver_data; + + if (!req->context) + return; + if (req->status) + epdata->status = req->status; + else + epdata->status = req->actual; + complete ((struct completion *)req->context); +} + +/* tasklock endpoint, returning when it's connected. + * still need dev->lock to use epdata->ep. + */ +static int +get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write) +{ + int val; + + if (f_flags & O_NONBLOCK) { + if (!mutex_trylock(&epdata->lock)) + goto nonblock; + if (epdata->state != STATE_EP_ENABLED && + (!is_write || epdata->state != STATE_EP_READY)) { + mutex_unlock(&epdata->lock); +nonblock: + val = -EAGAIN; + } else + val = 0; + return val; + } + + val = mutex_lock_interruptible(&epdata->lock); + if (val < 0) + return val; + + switch (epdata->state) { + case STATE_EP_ENABLED: + return 0; + case STATE_EP_READY: /* not configured yet */ + if (is_write) + return 0; + fallthrough; + case STATE_EP_UNBOUND: /* clean disconnect */ + break; + // case STATE_EP_DISABLED: /* "can't happen" */ + default: /* error! */ + pr_debug ("%s: ep %p not available, state %d\n", + shortname, epdata, epdata->state); + } + mutex_unlock(&epdata->lock); + return -ENODEV; +} + +static ssize_t +ep_io (struct ep_data *epdata, void *buf, unsigned len) +{ + DECLARE_COMPLETION_ONSTACK (done); + int value; + + spin_lock_irq (&epdata->dev->lock); + if (likely (epdata->ep != NULL)) { + struct usb_request *req = epdata->req; + + req->context = &done; + req->complete = epio_complete; + req->buf = buf; + req->length = len; + value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC); + } else + value = -ENODEV; + spin_unlock_irq (&epdata->dev->lock); + + if (likely (value == 0)) { + value = wait_for_completion_interruptible(&done); + if (value != 0) { + spin_lock_irq (&epdata->dev->lock); + if (likely (epdata->ep != NULL)) { + DBG (epdata->dev, "%s i/o interrupted\n", + epdata->name); + usb_ep_dequeue (epdata->ep, epdata->req); + spin_unlock_irq (&epdata->dev->lock); + + wait_for_completion(&done); + if (epdata->status == -ECONNRESET) + epdata->status = -EINTR; + } else { + spin_unlock_irq (&epdata->dev->lock); + + DBG (epdata->dev, "endpoint gone\n"); + wait_for_completion(&done); + epdata->status = -ENODEV; + } + } + return epdata->status; + } + return value; +} + +static int +ep_release (struct inode *inode, struct file *fd) +{ + struct ep_data *data = fd->private_data; + int value; + + value = mutex_lock_interruptible(&data->lock); + if (value < 0) + return value; + + /* clean up if this can be reopened */ + if (data->state != STATE_EP_UNBOUND) { + data->state = STATE_EP_DISABLED; + data->desc.bDescriptorType = 0; + data->hs_desc.bDescriptorType = 0; + usb_ep_disable(data->ep); + } + mutex_unlock(&data->lock); + put_ep (data); + return 0; +} + +static long ep_ioctl(struct file *fd, unsigned code, unsigned long value) +{ + struct ep_data *data = fd->private_data; + int status; + + if ((status = get_ready_ep (fd->f_flags, data, false)) < 0) + return status; + + spin_lock_irq (&data->dev->lock); + if (likely (data->ep != NULL)) { + switch (code) { + case GADGETFS_FIFO_STATUS: + status = usb_ep_fifo_status (data->ep); + break; + case GADGETFS_FIFO_FLUSH: + usb_ep_fifo_flush (data->ep); + break; + case GADGETFS_CLEAR_HALT: + status = usb_ep_clear_halt (data->ep); + break; + default: + status = -ENOTTY; + } + } else + status = -ENODEV; + spin_unlock_irq (&data->dev->lock); + mutex_unlock(&data->lock); + return status; +} + +/*----------------------------------------------------------------------*/ + +/* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */ + +struct kiocb_priv { + struct usb_request *req; + struct ep_data *epdata; + struct kiocb *iocb; + struct mm_struct *mm; + struct work_struct work; + void *buf; + struct iov_iter to; + const void *to_free; + unsigned actual; +}; + +static int ep_aio_cancel(struct kiocb *iocb) +{ + struct kiocb_priv *priv = iocb->private; + struct ep_data *epdata; + int value; + + local_irq_disable(); + epdata = priv->epdata; + // spin_lock(&epdata->dev->lock); + if (likely(epdata && epdata->ep && priv->req)) + value = usb_ep_dequeue (epdata->ep, priv->req); + else + value = -EINVAL; + // spin_unlock(&epdata->dev->lock); + local_irq_enable(); + + return value; +} + +static void ep_user_copy_worker(struct work_struct *work) +{ + struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work); + struct mm_struct *mm = priv->mm; + struct kiocb *iocb = priv->iocb; + size_t ret; + + kthread_use_mm(mm); + ret = copy_to_iter(priv->buf, priv->actual, &priv->to); + kthread_unuse_mm(mm); + if (!ret) + ret = -EFAULT; + + /* completing the iocb can drop the ctx and mm, don't touch mm after */ + iocb->ki_complete(iocb, ret); + + kfree(priv->buf); + kfree(priv->to_free); + kfree(priv); +} + +static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req) +{ + struct kiocb *iocb = req->context; + struct kiocb_priv *priv = iocb->private; + struct ep_data *epdata = priv->epdata; + + /* lock against disconnect (and ideally, cancel) */ + spin_lock(&epdata->dev->lock); + priv->req = NULL; + priv->epdata = NULL; + + /* if this was a write or a read returning no data then we + * don't need to copy anything to userspace, so we can + * complete the aio request immediately. + */ + if (priv->to_free == NULL || unlikely(req->actual == 0)) { + kfree(req->buf); + kfree(priv->to_free); + kfree(priv); + iocb->private = NULL; + iocb->ki_complete(iocb, + req->actual ? req->actual : (long)req->status); + } else { + /* ep_copy_to_user() won't report both; we hide some faults */ + if (unlikely(0 != req->status)) + DBG(epdata->dev, "%s fault %d len %d\n", + ep->name, req->status, req->actual); + + priv->buf = req->buf; + priv->actual = req->actual; + INIT_WORK(&priv->work, ep_user_copy_worker); + schedule_work(&priv->work); + } + + usb_ep_free_request(ep, req); + spin_unlock(&epdata->dev->lock); + put_ep(epdata); +} + +static ssize_t ep_aio(struct kiocb *iocb, + struct kiocb_priv *priv, + struct ep_data *epdata, + char *buf, + size_t len) +{ + struct usb_request *req; + ssize_t value; + + iocb->private = priv; + priv->iocb = iocb; + + kiocb_set_cancel_fn(iocb, ep_aio_cancel); + get_ep(epdata); + priv->epdata = epdata; + priv->actual = 0; + priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */ + + /* each kiocb is coupled to one usb_request, but we can't + * allocate or submit those if the host disconnected. + */ + spin_lock_irq(&epdata->dev->lock); + value = -ENODEV; + if (unlikely(epdata->ep == NULL)) + goto fail; + + req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC); + value = -ENOMEM; + if (unlikely(!req)) + goto fail; + + priv->req = req; + req->buf = buf; + req->length = len; + req->complete = ep_aio_complete; + req->context = iocb; + value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC); + if (unlikely(0 != value)) { + usb_ep_free_request(epdata->ep, req); + goto fail; + } + spin_unlock_irq(&epdata->dev->lock); + return -EIOCBQUEUED; + +fail: + spin_unlock_irq(&epdata->dev->lock); + kfree(priv->to_free); + kfree(priv); + put_ep(epdata); + return value; +} + +static ssize_t +ep_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct file *file = iocb->ki_filp; + struct ep_data *epdata = file->private_data; + size_t len = iov_iter_count(to); + ssize_t value; + char *buf; + + if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0) + return value; + + /* halt any endpoint by doing a "wrong direction" i/o call */ + if (usb_endpoint_dir_in(&epdata->desc)) { + if (usb_endpoint_xfer_isoc(&epdata->desc) || + !is_sync_kiocb(iocb)) { + mutex_unlock(&epdata->lock); + return -EINVAL; + } + DBG (epdata->dev, "%s halt\n", epdata->name); + spin_lock_irq(&epdata->dev->lock); + if (likely(epdata->ep != NULL)) + usb_ep_set_halt(epdata->ep); + spin_unlock_irq(&epdata->dev->lock); + mutex_unlock(&epdata->lock); + return -EBADMSG; + } + + buf = kmalloc(len, GFP_KERNEL); + if (unlikely(!buf)) { + mutex_unlock(&epdata->lock); + return -ENOMEM; + } + if (is_sync_kiocb(iocb)) { + value = ep_io(epdata, buf, len); + if (value >= 0 && (copy_to_iter(buf, value, to) != value)) + value = -EFAULT; + } else { + struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL); + value = -ENOMEM; + if (!priv) + goto fail; + priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL); + if (!priv->to_free) { + kfree(priv); + goto fail; + } + value = ep_aio(iocb, priv, epdata, buf, len); + if (value == -EIOCBQUEUED) + buf = NULL; + } +fail: + kfree(buf); + mutex_unlock(&epdata->lock); + return value; +} + +static ssize_t ep_config(struct ep_data *, const char *, size_t); + +static ssize_t +ep_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct ep_data *epdata = file->private_data; + size_t len = iov_iter_count(from); + bool configured; + ssize_t value; + char *buf; + + if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0) + return value; + + configured = epdata->state == STATE_EP_ENABLED; + + /* halt any endpoint by doing a "wrong direction" i/o call */ + if (configured && !usb_endpoint_dir_in(&epdata->desc)) { + if (usb_endpoint_xfer_isoc(&epdata->desc) || + !is_sync_kiocb(iocb)) { + mutex_unlock(&epdata->lock); + return -EINVAL; + } + DBG (epdata->dev, "%s halt\n", epdata->name); + spin_lock_irq(&epdata->dev->lock); + if (likely(epdata->ep != NULL)) + usb_ep_set_halt(epdata->ep); + spin_unlock_irq(&epdata->dev->lock); + mutex_unlock(&epdata->lock); + return -EBADMSG; + } + + buf = kmalloc(len, GFP_KERNEL); + if (unlikely(!buf)) { + mutex_unlock(&epdata->lock); + return -ENOMEM; + } + + if (unlikely(!copy_from_iter_full(buf, len, from))) { + value = -EFAULT; + goto out; + } + + if (unlikely(!configured)) { + value = ep_config(epdata, buf, len); + } else if (is_sync_kiocb(iocb)) { + value = ep_io(epdata, buf, len); + } else { + struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL); + value = -ENOMEM; + if (priv) { + value = ep_aio(iocb, priv, epdata, buf, len); + if (value == -EIOCBQUEUED) + buf = NULL; + } + } +out: + kfree(buf); + mutex_unlock(&epdata->lock); + return value; +} + +/*----------------------------------------------------------------------*/ + +/* used after endpoint configuration */ +static const struct file_operations ep_io_operations = { + .owner = THIS_MODULE, + + .open = ep_open, + .release = ep_release, + .llseek = no_llseek, + .unlocked_ioctl = ep_ioctl, + .read_iter = ep_read_iter, + .write_iter = ep_write_iter, +}; + +/* ENDPOINT INITIALIZATION + * + * fd = open ("/dev/gadget/$ENDPOINT", O_RDWR) + * status = write (fd, descriptors, sizeof descriptors) + * + * That write establishes the endpoint configuration, configuring + * the controller to process bulk, interrupt, or isochronous transfers + * at the right maxpacket size, and so on. + * + * The descriptors are message type 1, identified by a host order u32 + * at the beginning of what's written. Descriptor order is: full/low + * speed descriptor, then optional high speed descriptor. + */ +static ssize_t +ep_config (struct ep_data *data, const char *buf, size_t len) +{ + struct usb_ep *ep; + u32 tag; + int value, length = len; + + if (data->state != STATE_EP_READY) { + value = -EL2HLT; + goto fail; + } + + value = len; + if (len < USB_DT_ENDPOINT_SIZE + 4) + goto fail0; + + /* we might need to change message format someday */ + memcpy(&tag, buf, 4); + if (tag != 1) { + DBG(data->dev, "config %s, bad tag %d\n", data->name, tag); + goto fail0; + } + buf += 4; + len -= 4; + + /* NOTE: audio endpoint extensions not accepted here; + * just don't include the extra bytes. + */ + + /* full/low speed descriptor, then high speed */ + memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE); + if (data->desc.bLength != USB_DT_ENDPOINT_SIZE + || data->desc.bDescriptorType != USB_DT_ENDPOINT) + goto fail0; + if (len != USB_DT_ENDPOINT_SIZE) { + if (len != 2 * USB_DT_ENDPOINT_SIZE) + goto fail0; + memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE, + USB_DT_ENDPOINT_SIZE); + if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE + || data->hs_desc.bDescriptorType + != USB_DT_ENDPOINT) { + DBG(data->dev, "config %s, bad hs length or type\n", + data->name); + goto fail0; + } + } + + spin_lock_irq (&data->dev->lock); + if (data->dev->state == STATE_DEV_UNBOUND) { + value = -ENOENT; + goto gone; + } else { + ep = data->ep; + if (ep == NULL) { + value = -ENODEV; + goto gone; + } + } + switch (data->dev->gadget->speed) { + case USB_SPEED_LOW: + case USB_SPEED_FULL: + ep->desc = &data->desc; + break; + case USB_SPEED_HIGH: + /* fails if caller didn't provide that descriptor... */ + ep->desc = &data->hs_desc; + break; + default: + DBG(data->dev, "unconnected, %s init abandoned\n", + data->name); + value = -EINVAL; + goto gone; + } + value = usb_ep_enable(ep); + if (value == 0) { + data->state = STATE_EP_ENABLED; + value = length; + } +gone: + spin_unlock_irq (&data->dev->lock); + if (value < 0) { +fail: + data->desc.bDescriptorType = 0; + data->hs_desc.bDescriptorType = 0; + } + return value; +fail0: + value = -EINVAL; + goto fail; +} + +static int +ep_open (struct inode *inode, struct file *fd) +{ + struct ep_data *data = inode->i_private; + int value = -EBUSY; + + if (mutex_lock_interruptible(&data->lock) != 0) + return -EINTR; + spin_lock_irq (&data->dev->lock); + if (data->dev->state == STATE_DEV_UNBOUND) + value = -ENOENT; + else if (data->state == STATE_EP_DISABLED) { + value = 0; + data->state = STATE_EP_READY; + get_ep (data); + fd->private_data = data; + VDEBUG (data->dev, "%s ready\n", data->name); + } else + DBG (data->dev, "%s state %d\n", + data->name, data->state); + spin_unlock_irq (&data->dev->lock); + mutex_unlock(&data->lock); + return value; +} + +/*----------------------------------------------------------------------*/ + +/* EP0 IMPLEMENTATION can be partly in userspace. + * + * Drivers that use this facility receive various events, including + * control requests the kernel doesn't handle. Drivers that don't + * use this facility may be too simple-minded for real applications. + */ + +static inline void ep0_readable (struct dev_data *dev) +{ + wake_up (&dev->wait); + kill_fasync (&dev->fasync, SIGIO, POLL_IN); +} + +static void clean_req (struct usb_ep *ep, struct usb_request *req) +{ + struct dev_data *dev = ep->driver_data; + + if (req->buf != dev->rbuf) { + kfree(req->buf); + req->buf = dev->rbuf; + } + req->complete = epio_complete; + dev->setup_out_ready = 0; +} + +static void ep0_complete (struct usb_ep *ep, struct usb_request *req) +{ + struct dev_data *dev = ep->driver_data; + unsigned long flags; + int free = 1; + + /* for control OUT, data must still get to userspace */ + spin_lock_irqsave(&dev->lock, flags); + if (!dev->setup_in) { + dev->setup_out_error = (req->status != 0); + if (!dev->setup_out_error) + free = 0; + dev->setup_out_ready = 1; + ep0_readable (dev); + } + + /* clean up as appropriate */ + if (free && req->buf != &dev->rbuf) + clean_req (ep, req); + req->complete = epio_complete; + spin_unlock_irqrestore(&dev->lock, flags); +} + +static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len) +{ + struct dev_data *dev = ep->driver_data; + + if (dev->setup_out_ready) { + DBG (dev, "ep0 request busy!\n"); + return -EBUSY; + } + if (len > sizeof (dev->rbuf)) + req->buf = kmalloc(len, GFP_ATOMIC); + if (req->buf == NULL) { + req->buf = dev->rbuf; + return -ENOMEM; + } + req->complete = ep0_complete; + req->length = len; + req->zero = 0; + return 0; +} + +static ssize_t +ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr) +{ + struct dev_data *dev = fd->private_data; + ssize_t retval; + enum ep0_state state; + + spin_lock_irq (&dev->lock); + if (dev->state <= STATE_DEV_OPENED) { + retval = -EINVAL; + goto done; + } + + /* report fd mode change before acting on it */ + if (dev->setup_abort) { + dev->setup_abort = 0; + retval = -EIDRM; + goto done; + } + + /* control DATA stage */ + if ((state = dev->state) == STATE_DEV_SETUP) { + + if (dev->setup_in) { /* stall IN */ + VDEBUG(dev, "ep0in stall\n"); + (void) usb_ep_set_halt (dev->gadget->ep0); + retval = -EL2HLT; + dev->state = STATE_DEV_CONNECTED; + + } else if (len == 0) { /* ack SET_CONFIGURATION etc */ + struct usb_ep *ep = dev->gadget->ep0; + struct usb_request *req = dev->req; + + if ((retval = setup_req (ep, req, 0)) == 0) { + ++dev->udc_usage; + spin_unlock_irq (&dev->lock); + retval = usb_ep_queue (ep, req, GFP_KERNEL); + spin_lock_irq (&dev->lock); + --dev->udc_usage; + } + dev->state = STATE_DEV_CONNECTED; + + /* assume that was SET_CONFIGURATION */ + if (dev->current_config) { + unsigned power; + + if (gadget_is_dualspeed(dev->gadget) + && (dev->gadget->speed + == USB_SPEED_HIGH)) + power = dev->hs_config->bMaxPower; + else + power = dev->config->bMaxPower; + usb_gadget_vbus_draw(dev->gadget, 2 * power); + } + + } else { /* collect OUT data */ + if ((fd->f_flags & O_NONBLOCK) != 0 + && !dev->setup_out_ready) { + retval = -EAGAIN; + goto done; + } + spin_unlock_irq (&dev->lock); + retval = wait_event_interruptible (dev->wait, + dev->setup_out_ready != 0); + + /* FIXME state could change from under us */ + spin_lock_irq (&dev->lock); + if (retval) + goto done; + + if (dev->state != STATE_DEV_SETUP) { + retval = -ECANCELED; + goto done; + } + dev->state = STATE_DEV_CONNECTED; + + if (dev->setup_out_error) + retval = -EIO; + else { + len = min (len, (size_t)dev->req->actual); + ++dev->udc_usage; + spin_unlock_irq(&dev->lock); + if (copy_to_user (buf, dev->req->buf, len)) + retval = -EFAULT; + else + retval = len; + spin_lock_irq(&dev->lock); + --dev->udc_usage; + clean_req (dev->gadget->ep0, dev->req); + /* NOTE userspace can't yet choose to stall */ + } + } + goto done; + } + + /* else normal: return event data */ + if (len < sizeof dev->event [0]) { + retval = -EINVAL; + goto done; + } + len -= len % sizeof (struct usb_gadgetfs_event); + dev->usermode_setup = 1; + +scan: + /* return queued events right away */ + if (dev->ev_next != 0) { + unsigned i, n; + + n = len / sizeof (struct usb_gadgetfs_event); + if (dev->ev_next < n) + n = dev->ev_next; + + /* ep0 i/o has special semantics during STATE_DEV_SETUP */ + for (i = 0; i < n; i++) { + if (dev->event [i].type == GADGETFS_SETUP) { + dev->state = STATE_DEV_SETUP; + n = i + 1; + break; + } + } + spin_unlock_irq (&dev->lock); + len = n * sizeof (struct usb_gadgetfs_event); + if (copy_to_user (buf, &dev->event, len)) + retval = -EFAULT; + else + retval = len; + if (len > 0) { + /* NOTE this doesn't guard against broken drivers; + * concurrent ep0 readers may lose events. + */ + spin_lock_irq (&dev->lock); + if (dev->ev_next > n) { + memmove(&dev->event[0], &dev->event[n], + sizeof (struct usb_gadgetfs_event) + * (dev->ev_next - n)); + } + dev->ev_next -= n; + spin_unlock_irq (&dev->lock); + } + return retval; + } + if (fd->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + goto done; + } + + switch (state) { + default: + DBG (dev, "fail %s, state %d\n", __func__, state); + retval = -ESRCH; + break; + case STATE_DEV_UNCONNECTED: + case STATE_DEV_CONNECTED: + spin_unlock_irq (&dev->lock); + DBG (dev, "%s wait\n", __func__); + + /* wait for events */ + retval = wait_event_interruptible (dev->wait, + dev->ev_next != 0); + if (retval < 0) + return retval; + spin_lock_irq (&dev->lock); + goto scan; + } + +done: + spin_unlock_irq (&dev->lock); + return retval; +} + +static struct usb_gadgetfs_event * +next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type) +{ + struct usb_gadgetfs_event *event; + unsigned i; + + switch (type) { + /* these events purge the queue */ + case GADGETFS_DISCONNECT: + if (dev->state == STATE_DEV_SETUP) + dev->setup_abort = 1; + fallthrough; + case GADGETFS_CONNECT: + dev->ev_next = 0; + break; + case GADGETFS_SETUP: /* previous request timed out */ + case GADGETFS_SUSPEND: /* same effect */ + /* these events can't be repeated */ + for (i = 0; i != dev->ev_next; i++) { + if (dev->event [i].type != type) + continue; + DBG(dev, "discard old event[%d] %d\n", i, type); + dev->ev_next--; + if (i == dev->ev_next) + break; + /* indices start at zero, for simplicity */ + memmove (&dev->event [i], &dev->event [i + 1], + sizeof (struct usb_gadgetfs_event) + * (dev->ev_next - i)); + } + break; + default: + BUG (); + } + VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type); + event = &dev->event [dev->ev_next++]; + BUG_ON (dev->ev_next > N_EVENT); + memset (event, 0, sizeof *event); + event->type = type; + return event; +} + +static ssize_t +ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr) +{ + struct dev_data *dev = fd->private_data; + ssize_t retval = -ESRCH; + + /* report fd mode change before acting on it */ + if (dev->setup_abort) { + dev->setup_abort = 0; + retval = -EIDRM; + + /* data and/or status stage for control request */ + } else if (dev->state == STATE_DEV_SETUP) { + + len = min_t(size_t, len, dev->setup_wLength); + if (dev->setup_in) { + retval = setup_req (dev->gadget->ep0, dev->req, len); + if (retval == 0) { + dev->state = STATE_DEV_CONNECTED; + ++dev->udc_usage; + spin_unlock_irq (&dev->lock); + if (copy_from_user (dev->req->buf, buf, len)) + retval = -EFAULT; + else { + if (len < dev->setup_wLength) + dev->req->zero = 1; + retval = usb_ep_queue ( + dev->gadget->ep0, dev->req, + GFP_KERNEL); + } + spin_lock_irq(&dev->lock); + --dev->udc_usage; + if (retval < 0) { + clean_req (dev->gadget->ep0, dev->req); + } else + retval = len; + + return retval; + } + + /* can stall some OUT transfers */ + } else if (dev->setup_can_stall) { + VDEBUG(dev, "ep0out stall\n"); + (void) usb_ep_set_halt (dev->gadget->ep0); + retval = -EL2HLT; + dev->state = STATE_DEV_CONNECTED; + } else { + DBG(dev, "bogus ep0out stall!\n"); + } + } else + DBG (dev, "fail %s, state %d\n", __func__, dev->state); + + return retval; +} + +static int +ep0_fasync (int f, struct file *fd, int on) +{ + struct dev_data *dev = fd->private_data; + // caller must F_SETOWN before signal delivery happens + VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off"); + return fasync_helper (f, fd, on, &dev->fasync); +} + +static struct usb_gadget_driver gadgetfs_driver; + +static int +dev_release (struct inode *inode, struct file *fd) +{ + struct dev_data *dev = fd->private_data; + + /* closing ep0 === shutdown all */ + + if (dev->gadget_registered) { + usb_gadget_unregister_driver (&gadgetfs_driver); + dev->gadget_registered = false; + } + + /* at this point "good" hardware has disconnected the + * device from USB; the host won't see it any more. + * alternatively, all host requests will time out. + */ + + kfree (dev->buf); + dev->buf = NULL; + + /* other endpoints were all decoupled from this device */ + spin_lock_irq(&dev->lock); + dev->state = STATE_DEV_DISABLED; + spin_unlock_irq(&dev->lock); + + put_dev (dev); + return 0; +} + +static __poll_t +ep0_poll (struct file *fd, poll_table *wait) +{ + struct dev_data *dev = fd->private_data; + __poll_t mask = 0; + + if (dev->state <= STATE_DEV_OPENED) + return DEFAULT_POLLMASK; + + poll_wait(fd, &dev->wait, wait); + + spin_lock_irq(&dev->lock); + + /* report fd mode change before acting on it */ + if (dev->setup_abort) { + dev->setup_abort = 0; + mask = EPOLLHUP; + goto out; + } + + if (dev->state == STATE_DEV_SETUP) { + if (dev->setup_in || dev->setup_can_stall) + mask = EPOLLOUT; + } else { + if (dev->ev_next != 0) + mask = EPOLLIN; + } +out: + spin_unlock_irq(&dev->lock); + return mask; +} + +static long gadget_dev_ioctl (struct file *fd, unsigned code, unsigned long value) +{ + struct dev_data *dev = fd->private_data; + struct usb_gadget *gadget = dev->gadget; + long ret = -ENOTTY; + + spin_lock_irq(&dev->lock); + if (dev->state == STATE_DEV_OPENED || + dev->state == STATE_DEV_UNBOUND) { + /* Not bound to a UDC */ + } else if (gadget->ops->ioctl) { + ++dev->udc_usage; + spin_unlock_irq(&dev->lock); + + ret = gadget->ops->ioctl (gadget, code, value); + + spin_lock_irq(&dev->lock); + --dev->udc_usage; + } + spin_unlock_irq(&dev->lock); + + return ret; +} + +/*----------------------------------------------------------------------*/ + +/* The in-kernel gadget driver handles most ep0 issues, in particular + * enumerating the single configuration (as provided from user space). + * + * Unrecognized ep0 requests may be handled in user space. + */ + +static void make_qualifier (struct dev_data *dev) +{ + struct usb_qualifier_descriptor qual; + struct usb_device_descriptor *desc; + + qual.bLength = sizeof qual; + qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER; + qual.bcdUSB = cpu_to_le16 (0x0200); + + desc = dev->dev; + qual.bDeviceClass = desc->bDeviceClass; + qual.bDeviceSubClass = desc->bDeviceSubClass; + qual.bDeviceProtocol = desc->bDeviceProtocol; + + /* assumes ep0 uses the same value for both speeds ... */ + qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket; + + qual.bNumConfigurations = 1; + qual.bRESERVED = 0; + + memcpy (dev->rbuf, &qual, sizeof qual); +} + +static int +config_buf (struct dev_data *dev, u8 type, unsigned index) +{ + int len; + int hs = 0; + + /* only one configuration */ + if (index > 0) + return -EINVAL; + + if (gadget_is_dualspeed(dev->gadget)) { + hs = (dev->gadget->speed == USB_SPEED_HIGH); + if (type == USB_DT_OTHER_SPEED_CONFIG) + hs = !hs; + } + if (hs) { + dev->req->buf = dev->hs_config; + len = le16_to_cpu(dev->hs_config->wTotalLength); + } else { + dev->req->buf = dev->config; + len = le16_to_cpu(dev->config->wTotalLength); + } + ((u8 *)dev->req->buf) [1] = type; + return len; +} + +static int +gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl) +{ + struct dev_data *dev = get_gadget_data (gadget); + struct usb_request *req = dev->req; + int value = -EOPNOTSUPP; + struct usb_gadgetfs_event *event; + u16 w_value = le16_to_cpu(ctrl->wValue); + u16 w_length = le16_to_cpu(ctrl->wLength); + + if (w_length > RBUF_SIZE) { + if (ctrl->bRequestType & USB_DIR_IN) { + /* Cast away the const, we are going to overwrite on purpose. */ + __le16 *temp = (__le16 *)&ctrl->wLength; + + *temp = cpu_to_le16(RBUF_SIZE); + w_length = RBUF_SIZE; + } else { + return value; + } + } + + spin_lock (&dev->lock); + dev->setup_abort = 0; + if (dev->state == STATE_DEV_UNCONNECTED) { + if (gadget_is_dualspeed(gadget) + && gadget->speed == USB_SPEED_HIGH + && dev->hs_config == NULL) { + spin_unlock(&dev->lock); + ERROR (dev, "no high speed config??\n"); + return -EINVAL; + } + + dev->state = STATE_DEV_CONNECTED; + + INFO (dev, "connected\n"); + event = next_event (dev, GADGETFS_CONNECT); + event->u.speed = gadget->speed; + ep0_readable (dev); + + /* host may have given up waiting for response. we can miss control + * requests handled lower down (device/endpoint status and features); + * then ep0_{read,write} will report the wrong status. controller + * driver will have aborted pending i/o. + */ + } else if (dev->state == STATE_DEV_SETUP) + dev->setup_abort = 1; + + req->buf = dev->rbuf; + req->context = NULL; + switch (ctrl->bRequest) { + + case USB_REQ_GET_DESCRIPTOR: + if (ctrl->bRequestType != USB_DIR_IN) + goto unrecognized; + switch (w_value >> 8) { + + case USB_DT_DEVICE: + value = min (w_length, (u16) sizeof *dev->dev); + dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket; + req->buf = dev->dev; + break; + case USB_DT_DEVICE_QUALIFIER: + if (!dev->hs_config) + break; + value = min (w_length, (u16) + sizeof (struct usb_qualifier_descriptor)); + make_qualifier (dev); + break; + case USB_DT_OTHER_SPEED_CONFIG: + case USB_DT_CONFIG: + value = config_buf (dev, + w_value >> 8, + w_value & 0xff); + if (value >= 0) + value = min (w_length, (u16) value); + break; + case USB_DT_STRING: + goto unrecognized; + + default: // all others are errors + break; + } + break; + + /* currently one config, two speeds */ + case USB_REQ_SET_CONFIGURATION: + if (ctrl->bRequestType != 0) + goto unrecognized; + if (0 == (u8) w_value) { + value = 0; + dev->current_config = 0; + usb_gadget_vbus_draw(gadget, 8 /* mA */ ); + // user mode expected to disable endpoints + } else { + u8 config, power; + + if (gadget_is_dualspeed(gadget) + && gadget->speed == USB_SPEED_HIGH) { + config = dev->hs_config->bConfigurationValue; + power = dev->hs_config->bMaxPower; + } else { + config = dev->config->bConfigurationValue; + power = dev->config->bMaxPower; + } + + if (config == (u8) w_value) { + value = 0; + dev->current_config = config; + usb_gadget_vbus_draw(gadget, 2 * power); + } + } + + /* report SET_CONFIGURATION like any other control request, + * except that usermode may not stall this. the next + * request mustn't be allowed start until this finishes: + * endpoints and threads set up, etc. + * + * NOTE: older PXA hardware (before PXA 255: without UDCCFR) + * has bad/racey automagic that prevents synchronizing here. + * even kernel mode drivers often miss them. + */ + if (value == 0) { + INFO (dev, "configuration #%d\n", dev->current_config); + usb_gadget_set_state(gadget, USB_STATE_CONFIGURED); + if (dev->usermode_setup) { + dev->setup_can_stall = 0; + goto delegate; + } + } + break; + +#ifndef CONFIG_USB_PXA25X + /* PXA automagically handles this request too */ + case USB_REQ_GET_CONFIGURATION: + if (ctrl->bRequestType != 0x80) + goto unrecognized; + *(u8 *)req->buf = dev->current_config; + value = min (w_length, (u16) 1); + break; +#endif + + default: +unrecognized: + VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n", + dev->usermode_setup ? "delegate" : "fail", + ctrl->bRequestType, ctrl->bRequest, + w_value, le16_to_cpu(ctrl->wIndex), w_length); + + /* if there's an ep0 reader, don't stall */ + if (dev->usermode_setup) { + dev->setup_can_stall = 1; +delegate: + dev->setup_in = (ctrl->bRequestType & USB_DIR_IN) + ? 1 : 0; + dev->setup_wLength = w_length; + dev->setup_out_ready = 0; + dev->setup_out_error = 0; + + /* read DATA stage for OUT right away */ + if (unlikely (!dev->setup_in && w_length)) { + value = setup_req (gadget->ep0, dev->req, + w_length); + if (value < 0) + break; + + ++dev->udc_usage; + spin_unlock (&dev->lock); + value = usb_ep_queue (gadget->ep0, dev->req, + GFP_KERNEL); + spin_lock (&dev->lock); + --dev->udc_usage; + if (value < 0) { + clean_req (gadget->ep0, dev->req); + break; + } + + /* we can't currently stall these */ + dev->setup_can_stall = 0; + } + + /* state changes when reader collects event */ + event = next_event (dev, GADGETFS_SETUP); + event->u.setup = *ctrl; + ep0_readable (dev); + spin_unlock (&dev->lock); + return 0; + } + } + + /* proceed with data transfer and status phases? */ + if (value >= 0 && dev->state != STATE_DEV_SETUP) { + req->length = value; + req->zero = value < w_length; + + ++dev->udc_usage; + spin_unlock (&dev->lock); + value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL); + spin_lock(&dev->lock); + --dev->udc_usage; + spin_unlock(&dev->lock); + if (value < 0) { + DBG (dev, "ep_queue --> %d\n", value); + req->status = 0; + } + return value; + } + + /* device stalls when value < 0 */ + spin_unlock (&dev->lock); + return value; +} + +static void destroy_ep_files (struct dev_data *dev) +{ + DBG (dev, "%s %d\n", __func__, dev->state); + + /* dev->state must prevent interference */ + spin_lock_irq (&dev->lock); + while (!list_empty(&dev->epfiles)) { + struct ep_data *ep; + struct inode *parent; + struct dentry *dentry; + + /* break link to FS */ + ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles); + list_del_init (&ep->epfiles); + spin_unlock_irq (&dev->lock); + + dentry = ep->dentry; + ep->dentry = NULL; + parent = d_inode(dentry->d_parent); + + /* break link to controller */ + mutex_lock(&ep->lock); + if (ep->state == STATE_EP_ENABLED) + (void) usb_ep_disable (ep->ep); + ep->state = STATE_EP_UNBOUND; + usb_ep_free_request (ep->ep, ep->req); + ep->ep = NULL; + mutex_unlock(&ep->lock); + + wake_up (&ep->wait); + put_ep (ep); + + /* break link to dcache */ + inode_lock(parent); + d_delete (dentry); + dput (dentry); + inode_unlock(parent); + + spin_lock_irq (&dev->lock); + } + spin_unlock_irq (&dev->lock); +} + + +static struct dentry * +gadgetfs_create_file (struct super_block *sb, char const *name, + void *data, const struct file_operations *fops); + +static int activate_ep_files (struct dev_data *dev) +{ + struct usb_ep *ep; + struct ep_data *data; + + gadget_for_each_ep (ep, dev->gadget) { + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + goto enomem0; + data->state = STATE_EP_DISABLED; + mutex_init(&data->lock); + init_waitqueue_head (&data->wait); + + strncpy (data->name, ep->name, sizeof (data->name) - 1); + refcount_set (&data->count, 1); + data->dev = dev; + get_dev (dev); + + data->ep = ep; + ep->driver_data = data; + + data->req = usb_ep_alloc_request (ep, GFP_KERNEL); + if (!data->req) + goto enomem1; + + data->dentry = gadgetfs_create_file (dev->sb, data->name, + data, &ep_io_operations); + if (!data->dentry) + goto enomem2; + list_add_tail (&data->epfiles, &dev->epfiles); + } + return 0; + +enomem2: + usb_ep_free_request (ep, data->req); +enomem1: + put_dev (dev); + kfree (data); +enomem0: + DBG (dev, "%s enomem\n", __func__); + destroy_ep_files (dev); + return -ENOMEM; +} + +static void +gadgetfs_unbind (struct usb_gadget *gadget) +{ + struct dev_data *dev = get_gadget_data (gadget); + + DBG (dev, "%s\n", __func__); + + spin_lock_irq (&dev->lock); + dev->state = STATE_DEV_UNBOUND; + while (dev->udc_usage > 0) { + spin_unlock_irq(&dev->lock); + usleep_range(1000, 2000); + spin_lock_irq(&dev->lock); + } + spin_unlock_irq (&dev->lock); + + destroy_ep_files (dev); + gadget->ep0->driver_data = NULL; + set_gadget_data (gadget, NULL); + + /* we've already been disconnected ... no i/o is active */ + if (dev->req) + usb_ep_free_request (gadget->ep0, dev->req); + DBG (dev, "%s done\n", __func__); + put_dev (dev); +} + +static struct dev_data *the_device; + +static int gadgetfs_bind(struct usb_gadget *gadget, + struct usb_gadget_driver *driver) +{ + struct dev_data *dev = the_device; + + if (!dev) + return -ESRCH; + if (0 != strcmp (CHIP, gadget->name)) { + pr_err("%s expected %s controller not %s\n", + shortname, CHIP, gadget->name); + return -ENODEV; + } + + set_gadget_data (gadget, dev); + dev->gadget = gadget; + gadget->ep0->driver_data = dev; + + /* preallocate control response and buffer */ + dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL); + if (!dev->req) + goto enomem; + dev->req->context = NULL; + dev->req->complete = epio_complete; + + if (activate_ep_files (dev) < 0) + goto enomem; + + INFO (dev, "bound to %s driver\n", gadget->name); + spin_lock_irq(&dev->lock); + dev->state = STATE_DEV_UNCONNECTED; + spin_unlock_irq(&dev->lock); + get_dev (dev); + return 0; + +enomem: + gadgetfs_unbind (gadget); + return -ENOMEM; +} + +static void +gadgetfs_disconnect (struct usb_gadget *gadget) +{ + struct dev_data *dev = get_gadget_data (gadget); + unsigned long flags; + + spin_lock_irqsave (&dev->lock, flags); + if (dev->state == STATE_DEV_UNCONNECTED) + goto exit; + dev->state = STATE_DEV_UNCONNECTED; + + INFO (dev, "disconnected\n"); + next_event (dev, GADGETFS_DISCONNECT); + ep0_readable (dev); +exit: + spin_unlock_irqrestore (&dev->lock, flags); +} + +static void +gadgetfs_suspend (struct usb_gadget *gadget) +{ + struct dev_data *dev = get_gadget_data (gadget); + unsigned long flags; + + INFO (dev, "suspended from state %d\n", dev->state); + spin_lock_irqsave(&dev->lock, flags); + switch (dev->state) { + case STATE_DEV_SETUP: // VERY odd... host died?? + case STATE_DEV_CONNECTED: + case STATE_DEV_UNCONNECTED: + next_event (dev, GADGETFS_SUSPEND); + ep0_readable (dev); + fallthrough; + default: + break; + } + spin_unlock_irqrestore(&dev->lock, flags); +} + +static struct usb_gadget_driver gadgetfs_driver = { + .function = (char *) driver_desc, + .bind = gadgetfs_bind, + .unbind = gadgetfs_unbind, + .setup = gadgetfs_setup, + .reset = gadgetfs_disconnect, + .disconnect = gadgetfs_disconnect, + .suspend = gadgetfs_suspend, + + .driver = { + .name = shortname, + }, +}; + +/*----------------------------------------------------------------------*/ +/* DEVICE INITIALIZATION + * + * fd = open ("/dev/gadget/$CHIP", O_RDWR) + * status = write (fd, descriptors, sizeof descriptors) + * + * That write establishes the device configuration, so the kernel can + * bind to the controller ... guaranteeing it can handle enumeration + * at all necessary speeds. Descriptor order is: + * + * . message tag (u32, host order) ... for now, must be zero; it + * would change to support features like multi-config devices + * . full/low speed config ... all wTotalLength bytes (with interface, + * class, altsetting, endpoint, and other descriptors) + * . high speed config ... all descriptors, for high speed operation; + * this one's optional except for high-speed hardware + * . device descriptor + * + * Endpoints are not yet enabled. Drivers must wait until device + * configuration and interface altsetting changes create + * the need to configure (or unconfigure) them. + * + * After initialization, the device stays active for as long as that + * $CHIP file is open. Events must then be read from that descriptor, + * such as configuration notifications. + */ + +static int is_valid_config(struct usb_config_descriptor *config, + unsigned int total) +{ + return config->bDescriptorType == USB_DT_CONFIG + && config->bLength == USB_DT_CONFIG_SIZE + && total >= USB_DT_CONFIG_SIZE + && config->bConfigurationValue != 0 + && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0 + && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0; + /* FIXME if gadget->is_otg, _must_ include an otg descriptor */ + /* FIXME check lengths: walk to end */ +} + +static ssize_t +dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr) +{ + struct dev_data *dev = fd->private_data; + ssize_t value, length = len; + unsigned total; + u32 tag; + char *kbuf; + + spin_lock_irq(&dev->lock); + if (dev->state > STATE_DEV_OPENED) { + value = ep0_write(fd, buf, len, ptr); + spin_unlock_irq(&dev->lock); + return value; + } + spin_unlock_irq(&dev->lock); + + if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) || + (len > PAGE_SIZE * 4)) + return -EINVAL; + + /* we might need to change message format someday */ + if (copy_from_user (&tag, buf, 4)) + return -EFAULT; + if (tag != 0) + return -EINVAL; + buf += 4; + length -= 4; + + kbuf = memdup_user(buf, length); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + + spin_lock_irq (&dev->lock); + value = -EINVAL; + if (dev->buf) { + spin_unlock_irq(&dev->lock); + kfree(kbuf); + return value; + } + dev->buf = kbuf; + + /* full or low speed config */ + dev->config = (void *) kbuf; + total = le16_to_cpu(dev->config->wTotalLength); + if (!is_valid_config(dev->config, total) || + total > length - USB_DT_DEVICE_SIZE) + goto fail; + kbuf += total; + length -= total; + + /* optional high speed config */ + if (kbuf [1] == USB_DT_CONFIG) { + dev->hs_config = (void *) kbuf; + total = le16_to_cpu(dev->hs_config->wTotalLength); + if (!is_valid_config(dev->hs_config, total) || + total > length - USB_DT_DEVICE_SIZE) + goto fail; + kbuf += total; + length -= total; + } else { + dev->hs_config = NULL; + } + + /* could support multiple configs, using another encoding! */ + + /* device descriptor (tweaked for paranoia) */ + if (length != USB_DT_DEVICE_SIZE) + goto fail; + dev->dev = (void *)kbuf; + if (dev->dev->bLength != USB_DT_DEVICE_SIZE + || dev->dev->bDescriptorType != USB_DT_DEVICE + || dev->dev->bNumConfigurations != 1) + goto fail; + dev->dev->bcdUSB = cpu_to_le16 (0x0200); + + /* triggers gadgetfs_bind(); then we can enumerate. */ + spin_unlock_irq (&dev->lock); + if (dev->hs_config) + gadgetfs_driver.max_speed = USB_SPEED_HIGH; + else + gadgetfs_driver.max_speed = USB_SPEED_FULL; + + value = usb_gadget_register_driver(&gadgetfs_driver); + if (value != 0) { + spin_lock_irq(&dev->lock); + goto fail; + } else { + /* at this point "good" hardware has for the first time + * let the USB the host see us. alternatively, if users + * unplug/replug that will clear all the error state. + * + * note: everything running before here was guaranteed + * to choke driver model style diagnostics. from here + * on, they can work ... except in cleanup paths that + * kick in after the ep0 descriptor is closed. + */ + value = len; + dev->gadget_registered = true; + } + return value; + +fail: + dev->config = NULL; + dev->hs_config = NULL; + dev->dev = NULL; + spin_unlock_irq (&dev->lock); + pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev); + kfree (dev->buf); + dev->buf = NULL; + return value; +} + +static int +gadget_dev_open (struct inode *inode, struct file *fd) +{ + struct dev_data *dev = inode->i_private; + int value = -EBUSY; + + spin_lock_irq(&dev->lock); + if (dev->state == STATE_DEV_DISABLED) { + dev->ev_next = 0; + dev->state = STATE_DEV_OPENED; + fd->private_data = dev; + get_dev (dev); + value = 0; + } + spin_unlock_irq(&dev->lock); + return value; +} + +static const struct file_operations ep0_operations = { + .llseek = no_llseek, + + .open = gadget_dev_open, + .read = ep0_read, + .write = dev_config, + .fasync = ep0_fasync, + .poll = ep0_poll, + .unlocked_ioctl = gadget_dev_ioctl, + .release = dev_release, +}; + +/*----------------------------------------------------------------------*/ + +/* FILESYSTEM AND SUPERBLOCK OPERATIONS + * + * Mounting the filesystem creates a controller file, used first for + * device configuration then later for event monitoring. + */ + + +/* FIXME PAM etc could set this security policy without mount options + * if epfiles inherited ownership and permissons from ep0 ... + */ + +static unsigned default_uid; +static unsigned default_gid; +static unsigned default_perm = S_IRUSR | S_IWUSR; + +module_param (default_uid, uint, 0644); +module_param (default_gid, uint, 0644); +module_param (default_perm, uint, 0644); + + +static struct inode * +gadgetfs_make_inode (struct super_block *sb, + void *data, const struct file_operations *fops, + int mode) +{ + struct inode *inode = new_inode (sb); + + if (inode) { + inode->i_ino = get_next_ino(); + inode->i_mode = mode; + inode->i_uid = make_kuid(&init_user_ns, default_uid); + inode->i_gid = make_kgid(&init_user_ns, default_gid); + inode->i_atime = inode->i_mtime = inode->i_ctime + = current_time(inode); + inode->i_private = data; + inode->i_fop = fops; + } + return inode; +} + +/* creates in fs root directory, so non-renamable and non-linkable. + * so inode and dentry are paired, until device reconfig. + */ +static struct dentry * +gadgetfs_create_file (struct super_block *sb, char const *name, + void *data, const struct file_operations *fops) +{ + struct dentry *dentry; + struct inode *inode; + + dentry = d_alloc_name(sb->s_root, name); + if (!dentry) + return NULL; + + inode = gadgetfs_make_inode (sb, data, fops, + S_IFREG | (default_perm & S_IRWXUGO)); + if (!inode) { + dput(dentry); + return NULL; + } + d_add (dentry, inode); + return dentry; +} + +static const struct super_operations gadget_fs_operations = { + .statfs = simple_statfs, + .drop_inode = generic_delete_inode, +}; + +static int +gadgetfs_fill_super (struct super_block *sb, struct fs_context *fc) +{ + struct inode *inode; + struct dev_data *dev; + int rc; + + mutex_lock(&sb_mutex); + + if (the_device) { + rc = -ESRCH; + goto Done; + } + + CHIP = usb_get_gadget_udc_name(); + if (!CHIP) { + rc = -ENODEV; + goto Done; + } + + /* superblock */ + sb->s_blocksize = PAGE_SIZE; + sb->s_blocksize_bits = PAGE_SHIFT; + sb->s_magic = GADGETFS_MAGIC; + sb->s_op = &gadget_fs_operations; + sb->s_time_gran = 1; + + /* root inode */ + inode = gadgetfs_make_inode (sb, + NULL, &simple_dir_operations, + S_IFDIR | S_IRUGO | S_IXUGO); + if (!inode) + goto Enomem; + inode->i_op = &simple_dir_inode_operations; + if (!(sb->s_root = d_make_root (inode))) + goto Enomem; + + /* the ep0 file is named after the controller we expect; + * user mode code can use it for sanity checks, like we do. + */ + dev = dev_new (); + if (!dev) + goto Enomem; + + dev->sb = sb; + dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations); + if (!dev->dentry) { + put_dev(dev); + goto Enomem; + } + + /* other endpoint files are available after hardware setup, + * from binding to a controller. + */ + the_device = dev; + rc = 0; + goto Done; + + Enomem: + kfree(CHIP); + CHIP = NULL; + rc = -ENOMEM; + + Done: + mutex_unlock(&sb_mutex); + return rc; +} + +/* "mount -t gadgetfs path /dev/gadget" ends up here */ +static int gadgetfs_get_tree(struct fs_context *fc) +{ + return get_tree_single(fc, gadgetfs_fill_super); +} + +static const struct fs_context_operations gadgetfs_context_ops = { + .get_tree = gadgetfs_get_tree, +}; + +static int gadgetfs_init_fs_context(struct fs_context *fc) +{ + fc->ops = &gadgetfs_context_ops; + return 0; +} + +static void +gadgetfs_kill_sb (struct super_block *sb) +{ + mutex_lock(&sb_mutex); + kill_litter_super (sb); + if (the_device) { + put_dev (the_device); + the_device = NULL; + } + kfree(CHIP); + CHIP = NULL; + mutex_unlock(&sb_mutex); +} + +/*----------------------------------------------------------------------*/ + +static struct file_system_type gadgetfs_type = { + .owner = THIS_MODULE, + .name = shortname, + .init_fs_context = gadgetfs_init_fs_context, + .kill_sb = gadgetfs_kill_sb, +}; +MODULE_ALIAS_FS("gadgetfs"); + +/*----------------------------------------------------------------------*/ + +static int __init gadgetfs_init (void) +{ + int status; + + status = register_filesystem (&gadgetfs_type); + if (status == 0) + pr_info ("%s: %s, version " DRIVER_VERSION "\n", + shortname, driver_desc); + return status; +} +module_init (gadgetfs_init); + +static void __exit gadgetfs_cleanup (void) +{ + pr_debug ("unregister %s\n", shortname); + unregister_filesystem (&gadgetfs_type); +} +module_exit (gadgetfs_cleanup); + |