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acrn-kernel/drivers/usb/core/message.c

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/*
* message.c - synchronous message handling
*/
#include <linux/config.h>
#ifdef CONFIG_USB_DEBUG
#define DEBUG
#else
#undef DEBUG
#endif
#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 <asm/byteorder.h>
#include "hcd.h" /* for usbcore internals */
#include "usb.h"
static void usb_api_blocking_completion(struct urb *urb, struct pt_regs *regs)
{
complete((struct completion *)urb->context);
}
static void timeout_kill(unsigned long data)
{
struct urb *urb = (struct urb *) data;
usb_unlink_urb(urb);
}
// Starts urb and waits for completion or timeout
// note that this call is NOT interruptible, while
// many device driver i/o requests should be interruptible
static int usb_start_wait_urb(struct urb *urb, int timeout, int* actual_length)
{
struct completion done;
struct timer_list timer;
int status;
init_completion(&done);
urb->context = &done;
urb->transfer_flags |= URB_ASYNC_UNLINK;
urb->actual_length = 0;
status = usb_submit_urb(urb, GFP_NOIO);
if (status == 0) {
if (timeout > 0) {
init_timer(&timer);
timer.expires = jiffies + msecs_to_jiffies(timeout);
timer.data = (unsigned long)urb;
timer.function = timeout_kill;
/* grr. timeout _should_ include submit delays. */
add_timer(&timer);
}
wait_for_completion(&done);
status = urb->status;
/* note: HCDs return ETIMEDOUT for other reasons too */
if (status == -ECONNRESET) {
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
);
if (urb->actual_length > 0)
status = 0;
else
status = -ETIMEDOUT;
}
if (timeout > 0)
del_timer_sync(&timer);
}
if (actual_length)
*actual_length = urb->actual_length;
usb_free_urb(urb);
return status;
}
/*-------------------------------------------------------------------*/
// 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_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.
*/
int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe,
void *data, int len, int *actual_length, int timeout)
{
struct urb *urb;
if (len < 0)
return -EINVAL;
urb=usb_alloc_urb(0, GFP_KERNEL);
if (!urb)
return -ENOMEM;
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 pt_regs *regs)
{
struct usb_sg_request *io = (struct usb_sg_request *) urb->context;
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
|| urb->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",
urb->status, io->status);
// BUG ();
}
if (io->status == 0 && urb->status && urb->status != -ECONNRESET) {
int i, found, status;
io->status = urb->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) {
status = usb_unlink_urb (io->urbs [i]);
if (status != -EINPROGRESS && status != -EBUSY)
dev_err (&io->dev->dev,
"%s, unlink --> %d\n",
__FUNCTION__, status);
} 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,
unsigned 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_ASYNC_UNLINK | 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;
io->urbs [i]->status = -EINPROGRESS;
io->urbs [i]->actual_length = 0;
if (dma) {
/* hc may use _only_ transfer_dma */
io->urbs [i]->transfer_dma = sg_dma_address (sg + i);
len = sg_dma_len (sg + i);
} 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);
for (i = 0; i < entries && !io->status; i++) {
int retval;
io->urbs [i]->dev = io->dev;
retval = usb_submit_urb (io->urbs [i], SLAB_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;
i--;
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:
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.
*/
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 */
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_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. Note that several fields are
* converted to the host CPU's byte order: the USB version (bcdUSB), and
* vendors product and version fields (idVendor, idProduct, and bcdDevice).
* That lets device drivers compare against non-byteswapped constants.
*
* 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 && dev->bus->op && dev->bus->op->disable)
dev->bus->op->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 (!klist_node_attached(&interface->dev.knode_bus))
continue;
dev_dbg (&dev->dev, "unregistering interface %s\n",
interface->dev.bus_id);
usb_remove_sysfs_intf_files(interface);
kfree(interface->cur_altsetting->string);
interface->cur_altsetting->string = NULL;
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 */
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);
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) {
usb_set_device_state(dev, USB_STATE_ADDRESS);
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;
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);
}
return 0;
}
static void 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);
}
/*
* 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.
*
* 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 rwsem; 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;
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.
*/
if (cp && configuration == 0)
dev_warn(&dev->dev, "config 0 descriptor??\n");
if (dev->state == USB_STATE_SUSPENDED)
return -EHOSTUNREACH;
/* 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] = kmalloc(
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;
}
}
}
/* 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)
goto free_interfaces;
dev->actconfig = cp;
if (!cp)
usb_set_device_state(dev, USB_STATE_ADDRESS);
else {
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];
memset(intf, 0, sizeof(*intf));
intfc = cp->intf_cache[i];
intf->altsetting = intfc->altsetting;
intf->num_altsetting = intfc->num_altsetting;
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.dma_mask = dev->dev.dma_mask;
intf->dev.release = release_interface;
device_initialize (&intf->dev);
sprintf (&intf->dev.bus_id[0], "%d-%s:%d.%d",
dev->bus->busnum, dev->devpath,
configuration,
alt->desc.bInterfaceNumber);
}
kfree(new_interfaces);
if ((cp->desc.iConfiguration) &&
(cp->string == NULL)) {
cp->string = kmalloc(256, GFP_KERNEL);
if (cp->string)
usb_string(dev, cp->desc.iConfiguration, cp->string, 256);
}
/* 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];
struct usb_interface_descriptor *desc;
desc = &intf->altsetting [0].desc;
dev_dbg (&dev->dev,
"adding %s (config #%d, interface %d)\n",
intf->dev.bus_id, configuration,
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;
}
if ((intf->cur_altsetting->desc.iInterface) &&
(intf->cur_altsetting->string == NULL)) {
intf->cur_altsetting->string = kmalloc(256, GFP_KERNEL);
if (intf->cur_altsetting->string)
usb_string(dev, intf->cur_altsetting->desc.iInterface,
intf->cur_altsetting->string, 256);
}
usb_create_sysfs_intf_files (intf);
}
}
return 0;
}
// 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_get_string);
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);
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