/* * message.c - synchronous message handling */ #include <linux/pci.h> /* for scatterlist macros */ #include <linux/usb.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/init.h> #include <linux/mm.h> #include <linux/timer.h> #include <linux/ctype.h> #include <linux/device.h> #include <linux/usb/quirks.h> #include <asm/byteorder.h> #include <asm/scatterlist.h> #include "hcd.h" /* for usbcore internals */ #include "usb.h" static void usb_api_blocking_completion(struct urb *urb) { complete((struct completion *)urb->context); } /* * Starts urb and waits for completion or timeout. Note that this call * is NOT interruptible. Many device driver i/o requests should be * interruptible and therefore these drivers should implement their * own interruptible routines. */ static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length) { struct completion done; unsigned long expire; int retval; int status = urb->status; init_completion(&done); urb->context = &done; urb->actual_length = 0; retval = usb_submit_urb(urb, GFP_NOIO); if (unlikely(retval)) goto out; expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT; if (!wait_for_completion_timeout(&done, expire)) { dev_dbg(&urb->dev->dev, "%s timed out on ep%d%s len=%d/%d\n", current->comm, usb_pipeendpoint(urb->pipe), usb_pipein(urb->pipe) ? "in" : "out", urb->actual_length, urb->transfer_buffer_length); usb_kill_urb(urb); retval = status == -ENOENT ? -ETIMEDOUT : status; } else retval = status; out: if (actual_length) *actual_length = urb->actual_length; usb_free_urb(urb); return retval; } /*-------------------------------------------------------------------*/ // returns status (negative) or length (positive) static int usb_internal_control_msg(struct usb_device *usb_dev, unsigned int pipe, struct usb_ctrlrequest *cmd, void *data, int len, int timeout) { struct urb *urb; int retv; int length; urb = usb_alloc_urb(0, GFP_NOIO); if (!urb) return -ENOMEM; usb_fill_control_urb(urb, usb_dev, pipe, (unsigned char *)cmd, data, len, usb_api_blocking_completion, NULL); retv = usb_start_wait_urb(urb, timeout, &length); if (retv < 0) return retv; else return length; } /** * usb_control_msg - Builds a control urb, sends it off and waits for completion * @dev: pointer to the usb device to send the message to * @pipe: endpoint "pipe" to send the message to * @request: USB message request value * @requesttype: USB message request type value * @value: USB message value * @index: USB message index value * @data: pointer to the data to send * @size: length in bytes of the data to send * @timeout: time in msecs to wait for the message to complete before * timing out (if 0 the wait is forever) * Context: !in_interrupt () * * This function sends a simple control message to a specified endpoint * and waits for the message to complete, or timeout. * * If successful, it returns the number of bytes transferred, otherwise a negative error number. * * Don't use this function from within an interrupt context, like a * bottom half handler. If you need an asynchronous message, or need to send * a message from within interrupt context, use usb_submit_urb() * If a thread in your driver uses this call, make sure your disconnect() * method can wait for it to complete. Since you don't have a handle on * the URB used, you can't cancel the request. */ int usb_control_msg(struct usb_device *dev, unsigned int pipe, __u8 request, __u8 requesttype, __u16 value, __u16 index, void *data, __u16 size, int timeout) { struct usb_ctrlrequest *dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO); int ret; if (!dr) return -ENOMEM; dr->bRequestType= requesttype; dr->bRequest = request; dr->wValue = cpu_to_le16p(&value); dr->wIndex = cpu_to_le16p(&index); dr->wLength = cpu_to_le16p(&size); //dbg("usb_control_msg"); ret = usb_internal_control_msg(dev, pipe, dr, data, size, timeout); kfree(dr); return ret; } /** * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion * @usb_dev: pointer to the usb device to send the message to * @pipe: endpoint "pipe" to send the message to * @data: pointer to the data to send * @len: length in bytes of the data to send * @actual_length: pointer to a location to put the actual length transferred in bytes * @timeout: time in msecs to wait for the message to complete before * timing out (if 0 the wait is forever) * Context: !in_interrupt () * * This function sends a simple interrupt message to a specified endpoint and * waits for the message to complete, or timeout. * * If successful, it returns 0, otherwise a negative error number. The number * of actual bytes transferred will be stored in the actual_length paramater. * * Don't use this function from within an interrupt context, like a bottom half * handler. If you need an asynchronous message, or need to send a message * from within interrupt context, use usb_submit_urb() If a thread in your * driver uses this call, make sure your disconnect() method can wait for it to * complete. Since you don't have a handle on the URB used, you can't cancel * the request. */ int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe, void *data, int len, int *actual_length, int timeout) { return usb_bulk_msg(usb_dev, pipe, data, len, actual_length, timeout); } EXPORT_SYMBOL_GPL(usb_interrupt_msg); /** * usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion * @usb_dev: pointer to the usb device to send the message to * @pipe: endpoint "pipe" to send the message to * @data: pointer to the data to send * @len: length in bytes of the data to send * @actual_length: pointer to a location to put the actual length transferred in bytes * @timeout: time in msecs to wait for the message to complete before * timing out (if 0 the wait is forever) * Context: !in_interrupt () * * This function sends a simple bulk message to a specified endpoint * and waits for the message to complete, or timeout. * * If successful, it returns 0, otherwise a negative error number. * The number of actual bytes transferred will be stored in the * actual_length paramater. * * Don't use this function from within an interrupt context, like a * bottom half handler. If you need an asynchronous message, or need to * send a message from within interrupt context, use usb_submit_urb() * If a thread in your driver uses this call, make sure your disconnect() * method can wait for it to complete. Since you don't have a handle on * the URB used, you can't cancel the request. * * Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT * ioctl, users are forced to abuse this routine by using it to submit * URBs for interrupt endpoints. We will take the liberty of creating * an interrupt URB (with the default interval) if the target is an * interrupt endpoint. */ int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe, void *data, int len, int *actual_length, int timeout) { struct urb *urb; struct usb_host_endpoint *ep; ep = (usb_pipein(pipe) ? usb_dev->ep_in : usb_dev->ep_out) [usb_pipeendpoint(pipe)]; if (!ep || len < 0) return -EINVAL; urb = usb_alloc_urb(0, GFP_KERNEL); if (!urb) return -ENOMEM; if ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT) { pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30); usb_fill_int_urb(urb, usb_dev, pipe, data, len, usb_api_blocking_completion, NULL, ep->desc.bInterval); } else usb_fill_bulk_urb(urb, usb_dev, pipe, data, len, usb_api_blocking_completion, NULL); return usb_start_wait_urb(urb, timeout, actual_length); } /*-------------------------------------------------------------------*/ static void sg_clean (struct usb_sg_request *io) { if (io->urbs) { while (io->entries--) usb_free_urb (io->urbs [io->entries]); kfree (io->urbs); io->urbs = NULL; } if (io->dev->dev.dma_mask != NULL) usb_buffer_unmap_sg (io->dev, io->pipe, io->sg, io->nents); io->dev = NULL; } static void sg_complete (struct urb *urb) { struct usb_sg_request *io = urb->context; int status = urb->status; spin_lock (&io->lock); /* In 2.5 we require hcds' endpoint queues not to progress after fault * reports, until the completion callback (this!) returns. That lets * device driver code (like this routine) unlink queued urbs first, * if it needs to, since the HC won't work on them at all. So it's * not possible for page N+1 to overwrite page N, and so on. * * That's only for "hard" faults; "soft" faults (unlinks) sometimes * complete before the HCD can get requests away from hardware, * though never during cleanup after a hard fault. */ if (io->status && (io->status != -ECONNRESET || status != -ECONNRESET) && urb->actual_length) { dev_err (io->dev->bus->controller, "dev %s ep%d%s scatterlist error %d/%d\n", io->dev->devpath, usb_pipeendpoint (urb->pipe), usb_pipein (urb->pipe) ? "in" : "out", status, io->status); // BUG (); } if (io->status == 0 && status && status != -ECONNRESET) { int i, found, retval; io->status = status; /* the previous urbs, and this one, completed already. * unlink pending urbs so they won't rx/tx bad data. * careful: unlink can sometimes be synchronous... */ spin_unlock (&io->lock); for (i = 0, found = 0; i < io->entries; i++) { if (!io->urbs [i] || !io->urbs [i]->dev) continue; if (found) { retval = usb_unlink_urb (io->urbs [i]); if (retval != -EINPROGRESS && retval != -ENODEV && retval != -EBUSY) dev_err (&io->dev->dev, "%s, unlink --> %d\n", __FUNCTION__, retval); } else if (urb == io->urbs [i]) found = 1; } spin_lock (&io->lock); } urb->dev = NULL; /* on the last completion, signal usb_sg_wait() */ io->bytes += urb->actual_length; io->count--; if (!io->count) complete (&io->complete); spin_unlock (&io->lock); } /** * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request * @io: request block being initialized. until usb_sg_wait() returns, * treat this as a pointer to an opaque block of memory, * @dev: the usb device that will send or receive the data * @pipe: endpoint "pipe" used to transfer the data * @period: polling rate for interrupt endpoints, in frames or * (for high speed endpoints) microframes; ignored for bulk * @sg: scatterlist entries * @nents: how many entries in the scatterlist * @length: how many bytes to send from the scatterlist, or zero to * send every byte identified in the list. * @mem_flags: SLAB_* flags affecting memory allocations in this call * * Returns zero for success, else a negative errno value. This initializes a * scatter/gather request, allocating resources such as I/O mappings and urb * memory (except maybe memory used by USB controller drivers). * * The request must be issued using usb_sg_wait(), which waits for the I/O to * complete (or to be canceled) and then cleans up all resources allocated by * usb_sg_init(). * * The request may be canceled with usb_sg_cancel(), either before or after * usb_sg_wait() is called. */ int usb_sg_init ( struct usb_sg_request *io, struct usb_device *dev, unsigned pipe, unsigned period, struct scatterlist *sg, int nents, size_t length, gfp_t mem_flags ) { int i; int urb_flags; int dma; if (!io || !dev || !sg || usb_pipecontrol (pipe) || usb_pipeisoc (pipe) || nents <= 0) return -EINVAL; spin_lock_init (&io->lock); io->dev = dev; io->pipe = pipe; io->sg = sg; io->nents = nents; /* not all host controllers use DMA (like the mainstream pci ones); * they can use PIO (sl811) or be software over another transport. */ dma = (dev->dev.dma_mask != NULL); if (dma) io->entries = usb_buffer_map_sg (dev, pipe, sg, nents); else io->entries = nents; /* initialize all the urbs we'll use */ if (io->entries <= 0) return io->entries; io->count = io->entries; io->urbs = kmalloc (io->entries * sizeof *io->urbs, mem_flags); if (!io->urbs) goto nomem; urb_flags = URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT; if (usb_pipein (pipe)) urb_flags |= URB_SHORT_NOT_OK; for (i = 0; i < io->entries; i++) { unsigned len; io->urbs [i] = usb_alloc_urb (0, mem_flags); if (!io->urbs [i]) { io->entries = i; goto nomem; } io->urbs [i]->dev = NULL; io->urbs [i]->pipe = pipe; io->urbs [i]->interval = period; io->urbs [i]->transfer_flags = urb_flags; io->urbs [i]->complete = sg_complete; io->urbs [i]->context = io; /* * Some systems need to revert to PIO when DMA is temporarily * unavailable. For their sakes, both transfer_buffer and * transfer_dma are set when possible. However this can only * work on systems without HIGHMEM, since DMA buffers located * in high memory are not directly addressable by the CPU for * PIO ... so when HIGHMEM is in use, transfer_buffer is NULL * to prevent stale pointers and to help spot bugs. */ if (dma) { io->urbs [i]->transfer_dma = sg_dma_address (sg + i); len = sg_dma_len (sg + i); #ifdef CONFIG_HIGHMEM io->urbs[i]->transfer_buffer = NULL; #else io->urbs[i]->transfer_buffer = page_address(sg[i].page) + sg[i].offset; #endif } else { /* hc may use _only_ transfer_buffer */ io->urbs [i]->transfer_buffer = page_address (sg [i].page) + sg [i].offset; len = sg [i].length; } if (length) { len = min_t (unsigned, len, length); length -= len; if (length == 0) io->entries = i + 1; } io->urbs [i]->transfer_buffer_length = len; } io->urbs [--i]->transfer_flags &= ~URB_NO_INTERRUPT; /* transaction state */ io->status = 0; io->bytes = 0; init_completion (&io->complete); return 0; nomem: sg_clean (io); return -ENOMEM; } /** * usb_sg_wait - synchronously execute scatter/gather request * @io: request block handle, as initialized with usb_sg_init(). * some fields become accessible when this call returns. * Context: !in_interrupt () * * This function blocks until the specified I/O operation completes. It * leverages the grouping of the related I/O requests to get good transfer * rates, by queueing the requests. At higher speeds, such queuing can * significantly improve USB throughput. * * There are three kinds of completion for this function. * (1) success, where io->status is zero. The number of io->bytes * transferred is as requested. * (2) error, where io->status is a negative errno value. The number * of io->bytes transferred before the error is usually less * than requested, and can be nonzero. * (3) cancellation, a type of error with status -ECONNRESET that * is initiated by usb_sg_cancel(). * * When this function returns, all memory allocated through usb_sg_init() or * this call will have been freed. The request block parameter may still be * passed to usb_sg_cancel(), or it may be freed. It could also be * reinitialized and then reused. * * Data Transfer Rates: * * Bulk transfers are valid for full or high speed endpoints. * The best full speed data rate is 19 packets of 64 bytes each * per frame, or 1216 bytes per millisecond. * The best high speed data rate is 13 packets of 512 bytes each * per microframe, or 52 KBytes per millisecond. * * The reason to use interrupt transfers through this API would most likely * be to reserve high speed bandwidth, where up to 24 KBytes per millisecond * could be transferred. That capability is less useful for low or full * speed interrupt endpoints, which allow at most one packet per millisecond, * of at most 8 or 64 bytes (respectively). */ void usb_sg_wait (struct usb_sg_request *io) { int i, entries = io->entries; /* queue the urbs. */ spin_lock_irq (&io->lock); i = 0; while (i < entries && !io->status) { int retval; io->urbs [i]->dev = io->dev; retval = usb_submit_urb (io->urbs [i], GFP_ATOMIC); /* after we submit, let completions or cancelations fire; * we handshake using io->status. */ spin_unlock_irq (&io->lock); switch (retval) { /* maybe we retrying will recover */ case -ENXIO: // hc didn't queue this one case -EAGAIN: case -ENOMEM: io->urbs[i]->dev = NULL; retval = 0; yield (); break; /* no error? continue immediately. * * NOTE: to work better with UHCI (4K I/O buffer may * need 3K of TDs) it may be good to limit how many * URBs are queued at once; N milliseconds? */ case 0: ++i; cpu_relax (); break; /* fail any uncompleted urbs */ default: io->urbs [i]->dev = NULL; io->urbs [i]->status = retval; dev_dbg (&io->dev->dev, "%s, submit --> %d\n", __FUNCTION__, retval); usb_sg_cancel (io); } spin_lock_irq (&io->lock); if (retval && (io->status == 0 || io->status == -ECONNRESET)) io->status = retval; } io->count -= entries - i; if (io->count == 0) complete (&io->complete); spin_unlock_irq (&io->lock); /* OK, yes, this could be packaged as non-blocking. * So could the submit loop above ... but it's easier to * solve neither problem than to solve both! */ wait_for_completion (&io->complete); sg_clean (io); } /** * usb_sg_cancel - stop scatter/gather i/o issued by usb_sg_wait() * @io: request block, initialized with usb_sg_init() * * This stops a request after it has been started by usb_sg_wait(). * It can also prevents one initialized by usb_sg_init() from starting, * so that call just frees resources allocated to the request. */ void usb_sg_cancel (struct usb_sg_request *io) { unsigned long flags; spin_lock_irqsave (&io->lock, flags); /* shut everything down, if it didn't already */ if (!io->status) { int i; io->status = -ECONNRESET; spin_unlock (&io->lock); for (i = 0; i < io->entries; i++) { int retval; if (!io->urbs [i]->dev) continue; retval = usb_unlink_urb (io->urbs [i]); if (retval != -EINPROGRESS && retval != -EBUSY) dev_warn (&io->dev->dev, "%s, unlink --> %d\n", __FUNCTION__, retval); } spin_lock (&io->lock); } spin_unlock_irqrestore (&io->lock, flags); } /*-------------------------------------------------------------------*/ /** * usb_get_descriptor - issues a generic GET_DESCRIPTOR request * @dev: the device whose descriptor is being retrieved * @type: the descriptor type (USB_DT_*) * @index: the number of the descriptor * @buf: where to put the descriptor * @size: how big is "buf"? * Context: !in_interrupt () * * Gets a USB descriptor. Convenience functions exist to simplify * getting some types of descriptors. Use * usb_get_string() or usb_string() for USB_DT_STRING. * Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG) * are part of the device structure. * In addition to a number of USB-standard descriptors, some * devices also use class-specific or vendor-specific descriptors. * * This call is synchronous, and may not be used in an interrupt context. * * Returns the number of bytes received on success, or else the status code * returned by the underlying usb_control_msg() call. */ int usb_get_descriptor(struct usb_device *dev, unsigned char type, unsigned char index, void *buf, int size) { int i; int result; memset(buf,0,size); // Make sure we parse really received data for (i = 0; i < 3; ++i) { /* retry on length 0 or stall; some devices are flakey */ result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), USB_REQ_GET_DESCRIPTOR, USB_DIR_IN, (type << 8) + index, 0, buf, size, USB_CTRL_GET_TIMEOUT); if (result == 0 || result == -EPIPE) continue; if (result > 1 && ((u8 *)buf)[1] != type) { result = -EPROTO; continue; } break; } return result; } /** * usb_get_string - gets a string descriptor * @dev: the device whose string descriptor is being retrieved * @langid: code for language chosen (from string descriptor zero) * @index: the number of the descriptor * @buf: where to put the string * @size: how big is "buf"? * Context: !in_interrupt () * * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character, * in little-endian byte order). * The usb_string() function will often be a convenient way to turn * these strings into kernel-printable form. * * Strings may be referenced in device, configuration, interface, or other * descriptors, and could also be used in vendor-specific ways. * * This call is synchronous, and may not be used in an interrupt context. * * Returns the number of bytes received on success, or else the status code * returned by the underlying usb_control_msg() call. */ static int usb_get_string(struct usb_device *dev, unsigned short langid, unsigned char index, void *buf, int size) { int i; int result; for (i = 0; i < 3; ++i) { /* retry on length 0 or stall; some devices are flakey */ result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), USB_REQ_GET_DESCRIPTOR, USB_DIR_IN, (USB_DT_STRING << 8) + index, langid, buf, size, USB_CTRL_GET_TIMEOUT); if (!(result == 0 || result == -EPIPE)) break; } return result; } static void usb_try_string_workarounds(unsigned char *buf, int *length) { int newlength, oldlength = *length; for (newlength = 2; newlength + 1 < oldlength; newlength += 2) if (!isprint(buf[newlength]) || buf[newlength + 1]) break; if (newlength > 2) { buf[0] = newlength; *length = newlength; } } static int usb_string_sub(struct usb_device *dev, unsigned int langid, unsigned int index, unsigned char *buf) { int rc; /* Try to read the string descriptor by asking for the maximum * possible number of bytes */ if (dev->quirks & USB_QUIRK_STRING_FETCH_255) rc = -EIO; else rc = usb_get_string(dev, langid, index, buf, 255); /* If that failed try to read the descriptor length, then * ask for just that many bytes */ if (rc < 2) { rc = usb_get_string(dev, langid, index, buf, 2); if (rc == 2) rc = usb_get_string(dev, langid, index, buf, buf[0]); } if (rc >= 2) { if (!buf[0] && !buf[1]) usb_try_string_workarounds(buf, &rc); /* There might be extra junk at the end of the descriptor */ if (buf[0] < rc) rc = buf[0]; rc = rc - (rc & 1); /* force a multiple of two */ } if (rc < 2) rc = (rc < 0 ? rc : -EINVAL); return rc; } /** * usb_string - returns ISO 8859-1 version of a string descriptor * @dev: the device whose string descriptor is being retrieved * @index: the number of the descriptor * @buf: where to put the string * @size: how big is "buf"? * Context: !in_interrupt () * * This converts the UTF-16LE encoded strings returned by devices, from * usb_get_string_descriptor(), to null-terminated ISO-8859-1 encoded ones * that are more usable in most kernel contexts. Note that all characters * in the chosen descriptor that can't be encoded using ISO-8859-1 * are converted to the question mark ("?") character, and this function * chooses strings in the first language supported by the device. * * The ASCII (or, redundantly, "US-ASCII") character set is the seven-bit * subset of ISO 8859-1. ISO-8859-1 is the eight-bit subset of Unicode, * and is appropriate for use many uses of English and several other * Western European languages. (But it doesn't include the "Euro" symbol.) * * This call is synchronous, and may not be used in an interrupt context. * * Returns length of the string (>= 0) or usb_control_msg status (< 0). */ int usb_string(struct usb_device *dev, int index, char *buf, size_t size) { unsigned char *tbuf; int err; unsigned int u, idx; if (dev->state == USB_STATE_SUSPENDED) return -EHOSTUNREACH; if (size <= 0 || !buf || !index) return -EINVAL; buf[0] = 0; tbuf = kmalloc(256, GFP_KERNEL); if (!tbuf) return -ENOMEM; /* get langid for strings if it's not yet known */ if (!dev->have_langid) { err = usb_string_sub(dev, 0, 0, tbuf); if (err < 0) { dev_err (&dev->dev, "string descriptor 0 read error: %d\n", err); goto errout; } else if (err < 4) { dev_err (&dev->dev, "string descriptor 0 too short\n"); err = -EINVAL; goto errout; } else { dev->have_langid = 1; dev->string_langid = tbuf[2] | (tbuf[3]<< 8); /* always use the first langid listed */ dev_dbg (&dev->dev, "default language 0x%04x\n", dev->string_langid); } } err = usb_string_sub(dev, dev->string_langid, index, tbuf); if (err < 0) goto errout; size--; /* leave room for trailing NULL char in output buffer */ for (idx = 0, u = 2; u < err; u += 2) { if (idx >= size) break; if (tbuf[u+1]) /* high byte */ buf[idx++] = '?'; /* non ISO-8859-1 character */ else buf[idx++] = tbuf[u]; } buf[idx] = 0; err = idx; if (tbuf[1] != USB_DT_STRING) dev_dbg(&dev->dev, "wrong descriptor type %02x for string %d (\"%s\")\n", tbuf[1], index, buf); errout: kfree(tbuf); return err; } /** * usb_cache_string - read a string descriptor and cache it for later use * @udev: the device whose string descriptor is being read * @index: the descriptor index * * Returns a pointer to a kmalloc'ed buffer containing the descriptor string, * or NULL if the index is 0 or the string could not be read. */ char *usb_cache_string(struct usb_device *udev, int index) { char *buf; char *smallbuf = NULL; int len; if (index > 0 && (buf = kmalloc(256, GFP_KERNEL)) != NULL) { if ((len = usb_string(udev, index, buf, 256)) > 0) { if ((smallbuf = kmalloc(++len, GFP_KERNEL)) == NULL) return buf; memcpy(smallbuf, buf, len); } kfree(buf); } return smallbuf; } /* * usb_get_device_descriptor - (re)reads the device descriptor (usbcore) * @dev: the device whose device descriptor is being updated * @size: how much of the descriptor to read * Context: !in_interrupt () * * Updates the copy of the device descriptor stored in the device structure, * which dedicates space for this purpose. * * Not exported, only for use by the core. If drivers really want to read * the device descriptor directly, they can call usb_get_descriptor() with * type = USB_DT_DEVICE and index = 0. * * This call is synchronous, and may not be used in an interrupt context. * * Returns the number of bytes received on success, or else the status code * returned by the underlying usb_control_msg() call. */ int usb_get_device_descriptor(struct usb_device *dev, unsigned int size) { struct usb_device_descriptor *desc; int ret; if (size > sizeof(*desc)) return -EINVAL; desc = kmalloc(sizeof(*desc), GFP_NOIO); if (!desc) return -ENOMEM; ret = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, size); if (ret >= 0) memcpy(&dev->descriptor, desc, size); kfree(desc); return ret; } /** * usb_get_status - issues a GET_STATUS call * @dev: the device whose status is being checked * @type: USB_RECIP_*; for device, interface, or endpoint * @target: zero (for device), else interface or endpoint number * @data: pointer to two bytes of bitmap data * Context: !in_interrupt () * * Returns device, interface, or endpoint status. Normally only of * interest to see if the device is self powered, or has enabled the * remote wakeup facility; or whether a bulk or interrupt endpoint * is halted ("stalled"). * * Bits in these status bitmaps are set using the SET_FEATURE request, * and cleared using the CLEAR_FEATURE request. The usb_clear_halt() * function should be used to clear halt ("stall") status. * * This call is synchronous, and may not be used in an interrupt context. * * Returns the number of bytes received on success, or else the status code * returned by the underlying usb_control_msg() call. */ int usb_get_status(struct usb_device *dev, int type, int target, void *data) { int ret; u16 *status = kmalloc(sizeof(*status), GFP_KERNEL); if (!status) return -ENOMEM; ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), USB_REQ_GET_STATUS, USB_DIR_IN | type, 0, target, status, sizeof(*status), USB_CTRL_GET_TIMEOUT); *(u16 *)data = *status; kfree(status); return ret; } /** * usb_clear_halt - tells device to clear endpoint halt/stall condition * @dev: device whose endpoint is halted * @pipe: endpoint "pipe" being cleared * Context: !in_interrupt () * * This is used to clear halt conditions for bulk and interrupt endpoints, * as reported by URB completion status. Endpoints that are halted are * sometimes referred to as being "stalled". Such endpoints are unable * to transmit or receive data until the halt status is cleared. Any URBs * queued for such an endpoint should normally be unlinked by the driver * before clearing the halt condition, as described in sections 5.7.5 * and 5.8.5 of the USB 2.0 spec. * * Note that control and isochronous endpoints don't halt, although control * endpoints report "protocol stall" (for unsupported requests) using the * same status code used to report a true stall. * * This call is synchronous, and may not be used in an interrupt context. * * Returns zero on success, or else the status code returned by the * underlying usb_control_msg() call. */ int usb_clear_halt(struct usb_device *dev, int pipe) { int result; int endp = usb_pipeendpoint(pipe); if (usb_pipein (pipe)) endp |= USB_DIR_IN; /* we don't care if it wasn't halted first. in fact some devices * (like some ibmcam model 1 units) seem to expect hosts to make * this request for iso endpoints, which can't halt! */ result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT, USB_ENDPOINT_HALT, endp, NULL, 0, USB_CTRL_SET_TIMEOUT); /* don't un-halt or force to DATA0 except on success */ if (result < 0) return result; /* NOTE: seems like Microsoft and Apple don't bother verifying * the clear "took", so some devices could lock up if you check... * such as the Hagiwara FlashGate DUAL. So we won't bother. * * NOTE: make sure the logic here doesn't diverge much from * the copy in usb-storage, for as long as we need two copies. */ /* toggle was reset by the clear */ usb_settoggle(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe), 0); return 0; } /** * usb_disable_endpoint -- Disable an endpoint by address * @dev: the device whose endpoint is being disabled * @epaddr: the endpoint's address. Endpoint number for output, * endpoint number + USB_DIR_IN for input * * Deallocates hcd/hardware state for this endpoint ... and nukes all * pending urbs. * * If the HCD hasn't registered a disable() function, this sets the * endpoint's maxpacket size to 0 to prevent further submissions. */ void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr) { unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK; struct usb_host_endpoint *ep; if (!dev) return; if (usb_endpoint_out(epaddr)) { ep = dev->ep_out[epnum]; dev->ep_out[epnum] = NULL; } else { ep = dev->ep_in[epnum]; dev->ep_in[epnum] = NULL; } if (ep && dev->bus) usb_hcd_endpoint_disable(dev, ep); } /** * usb_disable_interface -- Disable all endpoints for an interface * @dev: the device whose interface is being disabled * @intf: pointer to the interface descriptor * * Disables all the endpoints for the interface's current altsetting. */ void usb_disable_interface(struct usb_device *dev, struct usb_interface *intf) { struct usb_host_interface *alt = intf->cur_altsetting; int i; for (i = 0; i < alt->desc.bNumEndpoints; ++i) { usb_disable_endpoint(dev, alt->endpoint[i].desc.bEndpointAddress); } } /* * usb_disable_device - Disable all the endpoints for a USB device * @dev: the device whose endpoints are being disabled * @skip_ep0: 0 to disable endpoint 0, 1 to skip it. * * Disables all the device's endpoints, potentially including endpoint 0. * Deallocates hcd/hardware state for the endpoints (nuking all or most * pending urbs) and usbcore state for the interfaces, so that usbcore * must usb_set_configuration() before any interfaces could be used. */ void usb_disable_device(struct usb_device *dev, int skip_ep0) { int i; dev_dbg(&dev->dev, "%s nuking %s URBs\n", __FUNCTION__, skip_ep0 ? "non-ep0" : "all"); for (i = skip_ep0; i < 16; ++i) { usb_disable_endpoint(dev, i); usb_disable_endpoint(dev, i + USB_DIR_IN); } dev->toggle[0] = dev->toggle[1] = 0; /* getting rid of interfaces will disconnect * any drivers bound to them (a key side effect) */ if (dev->actconfig) { for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) { struct usb_interface *interface; /* remove this interface if it has been registered */ interface = dev->actconfig->interface[i]; if (!device_is_registered(&interface->dev)) continue; dev_dbg (&dev->dev, "unregistering interface %s\n", interface->dev.bus_id); usb_remove_sysfs_intf_files(interface); device_del (&interface->dev); } /* Now that the interfaces are unbound, nobody should * try to access them. */ for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) { put_device (&dev->actconfig->interface[i]->dev); dev->actconfig->interface[i] = NULL; } dev->actconfig = NULL; if (dev->state == USB_STATE_CONFIGURED) usb_set_device_state(dev, USB_STATE_ADDRESS); } } /* * usb_enable_endpoint - Enable an endpoint for USB communications * @dev: the device whose interface is being enabled * @ep: the endpoint * * Resets the endpoint toggle, and sets dev->ep_{in,out} pointers. * For control endpoints, both the input and output sides are handled. */ static void usb_enable_endpoint(struct usb_device *dev, struct usb_host_endpoint *ep) { unsigned int epaddr = ep->desc.bEndpointAddress; unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK; int is_control; is_control = ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_CONTROL); if (usb_endpoint_out(epaddr) || is_control) { usb_settoggle(dev, epnum, 1, 0); dev->ep_out[epnum] = ep; } if (!usb_endpoint_out(epaddr) || is_control) { usb_settoggle(dev, epnum, 0, 0); dev->ep_in[epnum] = ep; } } /* * usb_enable_interface - Enable all the endpoints for an interface * @dev: the device whose interface is being enabled * @intf: pointer to the interface descriptor * * Enables all the endpoints for the interface's current altsetting. */ static void usb_enable_interface(struct usb_device *dev, struct usb_interface *intf) { struct usb_host_interface *alt = intf->cur_altsetting; int i; for (i = 0; i < alt->desc.bNumEndpoints; ++i) usb_enable_endpoint(dev, &alt->endpoint[i]); } /** * usb_set_interface - Makes a particular alternate setting be current * @dev: the device whose interface is being updated * @interface: the interface being updated * @alternate: the setting being chosen. * Context: !in_interrupt () * * This is used to enable data transfers on interfaces that may not * be enabled by default. Not all devices support such configurability. * Only the driver bound to an interface may change its setting. * * Within any given configuration, each interface may have several * alternative settings. These are often used to control levels of * bandwidth consumption. For example, the default setting for a high * speed interrupt endpoint may not send more than 64 bytes per microframe, * while interrupt transfers of up to 3KBytes per microframe are legal. * Also, isochronous endpoints may never be part of an * interface's default setting. To access such bandwidth, alternate * interface settings must be made current. * * Note that in the Linux USB subsystem, bandwidth associated with * an endpoint in a given alternate setting is not reserved until an URB * is submitted that needs that bandwidth. Some other operating systems * allocate bandwidth early, when a configuration is chosen. * * This call is synchronous, and may not be used in an interrupt context. * Also, drivers must not change altsettings while urbs are scheduled for * endpoints in that interface; all such urbs must first be completed * (perhaps forced by unlinking). * * Returns zero on success, or else the status code returned by the * underlying usb_control_msg() call. */ int usb_set_interface(struct usb_device *dev, int interface, int alternate) { struct usb_interface *iface; struct usb_host_interface *alt; int ret; int manual = 0; if (dev->state == USB_STATE_SUSPENDED) return -EHOSTUNREACH; iface = usb_ifnum_to_if(dev, interface); if (!iface) { dev_dbg(&dev->dev, "selecting invalid interface %d\n", interface); return -EINVAL; } alt = usb_altnum_to_altsetting(iface, alternate); if (!alt) { warn("selecting invalid altsetting %d", alternate); return -EINVAL; } ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE, alternate, interface, NULL, 0, 5000); /* 9.4.10 says devices don't need this and are free to STALL the * request if the interface only has one alternate setting. */ if (ret == -EPIPE && iface->num_altsetting == 1) { dev_dbg(&dev->dev, "manual set_interface for iface %d, alt %d\n", interface, alternate); manual = 1; } else if (ret < 0) return ret; /* FIXME drivers shouldn't need to replicate/bugfix the logic here * when they implement async or easily-killable versions of this or * other "should-be-internal" functions (like clear_halt). * should hcd+usbcore postprocess control requests? */ /* prevent submissions using previous endpoint settings */ if (device_is_registered(&iface->dev)) usb_remove_sysfs_intf_files(iface); usb_disable_interface(dev, iface); iface->cur_altsetting = alt; /* If the interface only has one altsetting and the device didn't * accept the request, we attempt to carry out the equivalent action * by manually clearing the HALT feature for each endpoint in the * new altsetting. */ if (manual) { int i; for (i = 0; i < alt->desc.bNumEndpoints; i++) { unsigned int epaddr = alt->endpoint[i].desc.bEndpointAddress; unsigned int pipe = __create_pipe(dev, USB_ENDPOINT_NUMBER_MASK & epaddr) | (usb_endpoint_out(epaddr) ? USB_DIR_OUT : USB_DIR_IN); usb_clear_halt(dev, pipe); } } /* 9.1.1.5: reset toggles for all endpoints in the new altsetting * * Note: * Despite EP0 is always present in all interfaces/AS, the list of * endpoints from the descriptor does not contain EP0. Due to its * omnipresence one might expect EP0 being considered "affected" by * any SetInterface request and hence assume toggles need to be reset. * However, EP0 toggles are re-synced for every individual transfer * during the SETUP stage - hence EP0 toggles are "don't care" here. * (Likewise, EP0 never "halts" on well designed devices.) */ usb_enable_interface(dev, iface); if (device_is_registered(&iface->dev)) usb_create_sysfs_intf_files(iface); return 0; } /** * usb_reset_configuration - lightweight device reset * @dev: the device whose configuration is being reset * * This issues a standard SET_CONFIGURATION request to the device using * the current configuration. The effect is to reset most USB-related * state in the device, including interface altsettings (reset to zero), * endpoint halts (cleared), and data toggle (only for bulk and interrupt * endpoints). Other usbcore state is unchanged, including bindings of * usb device drivers to interfaces. * * Because this affects multiple interfaces, avoid using this with composite * (multi-interface) devices. Instead, the driver for each interface may * use usb_set_interface() on the interfaces it claims. Be careful though; * some devices don't support the SET_INTERFACE request, and others won't * reset all the interface state (notably data toggles). Resetting the whole * configuration would affect other drivers' interfaces. * * The caller must own the device lock. * * Returns zero on success, else a negative error code. */ int usb_reset_configuration(struct usb_device *dev) { int i, retval; struct usb_host_config *config; if (dev->state == USB_STATE_SUSPENDED) return -EHOSTUNREACH; /* caller must have locked the device and must own * the usb bus readlock (so driver bindings are stable); * calls during probe() are fine */ for (i = 1; i < 16; ++i) { usb_disable_endpoint(dev, i); usb_disable_endpoint(dev, i + USB_DIR_IN); } config = dev->actconfig; retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), USB_REQ_SET_CONFIGURATION, 0, config->desc.bConfigurationValue, 0, NULL, 0, USB_CTRL_SET_TIMEOUT); if (retval < 0) return retval; dev->toggle[0] = dev->toggle[1] = 0; /* re-init hc/hcd interface/endpoint state */ for (i = 0; i < config->desc.bNumInterfaces; i++) { struct usb_interface *intf = config->interface[i]; struct usb_host_interface *alt; if (device_is_registered(&intf->dev)) usb_remove_sysfs_intf_files(intf); alt = usb_altnum_to_altsetting(intf, 0); /* No altsetting 0? We'll assume the first altsetting. * We could use a GetInterface call, but if a device is * so non-compliant that it doesn't have altsetting 0 * then I wouldn't trust its reply anyway. */ if (!alt) alt = &intf->altsetting[0]; intf->cur_altsetting = alt; usb_enable_interface(dev, intf); if (device_is_registered(&intf->dev)) usb_create_sysfs_intf_files(intf); } return 0; } void usb_release_interface(struct device *dev) { struct usb_interface *intf = to_usb_interface(dev); struct usb_interface_cache *intfc = altsetting_to_usb_interface_cache(intf->altsetting); kref_put(&intfc->ref, usb_release_interface_cache); kfree(intf); } #ifdef CONFIG_HOTPLUG static int usb_if_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size) { struct usb_device *usb_dev; struct usb_interface *intf; struct usb_host_interface *alt; int i = 0; int length = 0; if (!dev) return -ENODEV; /* driver is often null here; dev_dbg() would oops */ pr_debug ("usb %s: uevent\n", dev->bus_id); intf = to_usb_interface(dev); usb_dev = interface_to_usbdev(intf); alt = intf->cur_altsetting; if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length, "INTERFACE=%d/%d/%d", alt->desc.bInterfaceClass, alt->desc.bInterfaceSubClass, alt->desc.bInterfaceProtocol)) return -ENOMEM; if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length, "MODALIAS=usb:v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02X", le16_to_cpu(usb_dev->descriptor.idVendor), le16_to_cpu(usb_dev->descriptor.idProduct), le16_to_cpu(usb_dev->descriptor.bcdDevice), usb_dev->descriptor.bDeviceClass, usb_dev->descriptor.bDeviceSubClass, usb_dev->descriptor.bDeviceProtocol, alt->desc.bInterfaceClass, alt->desc.bInterfaceSubClass, alt->desc.bInterfaceProtocol)) return -ENOMEM; envp[i] = NULL; return 0; } #else static int usb_if_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size) { return -ENODEV; } #endif /* CONFIG_HOTPLUG */ struct device_type usb_if_device_type = { .name = "usb_interface", .release = usb_release_interface, .uevent = usb_if_uevent, }; static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev, struct usb_host_config *config, u8 inum) { struct usb_interface_assoc_descriptor *retval = NULL; struct usb_interface_assoc_descriptor *intf_assoc; int first_intf; int last_intf; int i; for (i = 0; (i < USB_MAXIADS && config->intf_assoc[i]); i++) { intf_assoc = config->intf_assoc[i]; if (intf_assoc->bInterfaceCount == 0) continue; first_intf = intf_assoc->bFirstInterface; last_intf = first_intf + (intf_assoc->bInterfaceCount - 1); if (inum >= first_intf && inum <= last_intf) { if (!retval) retval = intf_assoc; else dev_err(&dev->dev, "Interface #%d referenced" " by multiple IADs\n", inum); } } return retval; } /* * usb_set_configuration - Makes a particular device setting be current * @dev: the device whose configuration is being updated * @configuration: the configuration being chosen. * Context: !in_interrupt(), caller owns the device lock * * This is used to enable non-default device modes. Not all devices * use this kind of configurability; many devices only have one * configuration. * * @configuration is the value of the configuration to be installed. * According to the USB spec (e.g. section 9.1.1.5), configuration values * must be non-zero; a value of zero indicates that the device in * unconfigured. However some devices erroneously use 0 as one of their * configuration values. To help manage such devices, this routine will * accept @configuration = -1 as indicating the device should be put in * an unconfigured state. * * USB device configurations may affect Linux interoperability, * power consumption and the functionality available. For example, * the default configuration is limited to using 100mA of bus power, * so that when certain device functionality requires more power, * and the device is bus powered, that functionality should be in some * non-default device configuration. Other device modes may also be * reflected as configuration options, such as whether two ISDN * channels are available independently; and choosing between open * standard device protocols (like CDC) or proprietary ones. * * Note that USB has an additional level of device configurability, * associated with interfaces. That configurability is accessed using * usb_set_interface(). * * This call is synchronous. The calling context must be able to sleep, * must own the device lock, and must not hold the driver model's USB * bus mutex; usb device driver probe() methods cannot use this routine. * * Returns zero on success, or else the status code returned by the * underlying call that failed. On successful completion, each interface * in the original device configuration has been destroyed, and each one * in the new configuration has been probed by all relevant usb device * drivers currently known to the kernel. */ int usb_set_configuration(struct usb_device *dev, int configuration) { int i, ret; struct usb_host_config *cp = NULL; struct usb_interface **new_interfaces = NULL; int n, nintf; if (configuration == -1) configuration = 0; else { for (i = 0; i < dev->descriptor.bNumConfigurations; i++) { if (dev->config[i].desc.bConfigurationValue == configuration) { cp = &dev->config[i]; break; } } } if ((!cp && configuration != 0)) return -EINVAL; /* The USB spec says configuration 0 means unconfigured. * But if a device includes a configuration numbered 0, * we will accept it as a correctly configured state. * Use -1 if you really want to unconfigure the device. */ if (cp && configuration == 0) dev_warn(&dev->dev, "config 0 descriptor??\n"); /* Allocate memory for new interfaces before doing anything else, * so that if we run out then nothing will have changed. */ n = nintf = 0; if (cp) { nintf = cp->desc.bNumInterfaces; new_interfaces = kmalloc(nintf * sizeof(*new_interfaces), GFP_KERNEL); if (!new_interfaces) { dev_err(&dev->dev, "Out of memory"); return -ENOMEM; } for (; n < nintf; ++n) { new_interfaces[n] = kzalloc( sizeof(struct usb_interface), GFP_KERNEL); if (!new_interfaces[n]) { dev_err(&dev->dev, "Out of memory"); ret = -ENOMEM; free_interfaces: while (--n >= 0) kfree(new_interfaces[n]); kfree(new_interfaces); return ret; } } i = dev->bus_mA - cp->desc.bMaxPower * 2; if (i < 0) dev_warn(&dev->dev, "new config #%d exceeds power " "limit by %dmA\n", configuration, -i); } /* Wake up the device so we can send it the Set-Config request */ ret = usb_autoresume_device(dev); if (ret) goto free_interfaces; /* if it's already configured, clear out old state first. * getting rid of old interfaces means unbinding their drivers. */ if (dev->state != USB_STATE_ADDRESS) usb_disable_device (dev, 1); // Skip ep0 if ((ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), USB_REQ_SET_CONFIGURATION, 0, configuration, 0, NULL, 0, USB_CTRL_SET_TIMEOUT)) < 0) { /* All the old state is gone, so what else can we do? * The device is probably useless now anyway. */ cp = NULL; } dev->actconfig = cp; if (!cp) { usb_set_device_state(dev, USB_STATE_ADDRESS); usb_autosuspend_device(dev); goto free_interfaces; } usb_set_device_state(dev, USB_STATE_CONFIGURED); /* Initialize the new interface structures and the * hc/hcd/usbcore interface/endpoint state. */ for (i = 0; i < nintf; ++i) { struct usb_interface_cache *intfc; struct usb_interface *intf; struct usb_host_interface *alt; cp->interface[i] = intf = new_interfaces[i]; intfc = cp->intf_cache[i]; intf->altsetting = intfc->altsetting; intf->num_altsetting = intfc->num_altsetting; intf->intf_assoc = find_iad(dev, cp, i); kref_get(&intfc->ref); alt = usb_altnum_to_altsetting(intf, 0); /* No altsetting 0? We'll assume the first altsetting. * We could use a GetInterface call, but if a device is * so non-compliant that it doesn't have altsetting 0 * then I wouldn't trust its reply anyway. */ if (!alt) alt = &intf->altsetting[0]; intf->cur_altsetting = alt; usb_enable_interface(dev, intf); intf->dev.parent = &dev->dev; intf->dev.driver = NULL; intf->dev.bus = &usb_bus_type; intf->dev.type = &usb_if_device_type; intf->dev.dma_mask = dev->dev.dma_mask; device_initialize (&intf->dev); mark_quiesced(intf); sprintf (&intf->dev.bus_id[0], "%d-%s:%d.%d", dev->bus->busnum, dev->devpath, configuration, alt->desc.bInterfaceNumber); } kfree(new_interfaces); if (cp->string == NULL) cp->string = usb_cache_string(dev, cp->desc.iConfiguration); /* Now that all the interfaces are set up, register them * to trigger binding of drivers to interfaces. probe() * routines may install different altsettings and may * claim() any interfaces not yet bound. Many class drivers * need that: CDC, audio, video, etc. */ for (i = 0; i < nintf; ++i) { struct usb_interface *intf = cp->interface[i]; dev_dbg (&dev->dev, "adding %s (config #%d, interface %d)\n", intf->dev.bus_id, configuration, intf->cur_altsetting->desc.bInterfaceNumber); ret = device_add (&intf->dev); if (ret != 0) { dev_err(&dev->dev, "device_add(%s) --> %d\n", intf->dev.bus_id, ret); continue; } usb_create_sysfs_intf_files (intf); } usb_autosuspend_device(dev); return 0; } struct set_config_request { struct usb_device *udev; int config; struct work_struct work; }; /* Worker routine for usb_driver_set_configuration() */ static void driver_set_config_work(struct work_struct *work) { struct set_config_request *req = container_of(work, struct set_config_request, work); usb_lock_device(req->udev); usb_set_configuration(req->udev, req->config); usb_unlock_device(req->udev); usb_put_dev(req->udev); kfree(req); } /** * usb_driver_set_configuration - Provide a way for drivers to change device configurations * @udev: the device whose configuration is being updated * @config: the configuration being chosen. * Context: In process context, must be able to sleep * * Device interface drivers are not allowed to change device configurations. * This is because changing configurations will destroy the interface the * driver is bound to and create new ones; it would be like a floppy-disk * driver telling the computer to replace the floppy-disk drive with a * tape drive! * * Still, in certain specialized circumstances the need may arise. This * routine gets around the normal restrictions by using a work thread to * submit the change-config request. * * Returns 0 if the request was succesfully queued, error code otherwise. * The caller has no way to know whether the queued request will eventually * succeed. */ int usb_driver_set_configuration(struct usb_device *udev, int config) { struct set_config_request *req; req = kmalloc(sizeof(*req), GFP_KERNEL); if (!req) return -ENOMEM; req->udev = udev; req->config = config; INIT_WORK(&req->work, driver_set_config_work); usb_get_dev(udev); schedule_work(&req->work); return 0; } EXPORT_SYMBOL_GPL(usb_driver_set_configuration); // synchronous request completion model EXPORT_SYMBOL(usb_control_msg); EXPORT_SYMBOL(usb_bulk_msg); EXPORT_SYMBOL(usb_sg_init); EXPORT_SYMBOL(usb_sg_cancel); EXPORT_SYMBOL(usb_sg_wait); // synchronous control message convenience routines EXPORT_SYMBOL(usb_get_descriptor); EXPORT_SYMBOL(usb_get_status); EXPORT_SYMBOL(usb_string); // synchronous calls that also maintain usbcore state EXPORT_SYMBOL(usb_clear_halt); EXPORT_SYMBOL(usb_reset_configuration); EXPORT_SYMBOL(usb_set_interface);