linux/drivers/usb/core/message.c

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/*
* 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"
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
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 status;
init_completion(&done);
urb->context = &done;
urb->actual_length = 0;
status = usb_submit_urb(urb, GFP_NOIO);
if (unlikely(status))
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);
status = urb->status == -ENOENT ? -ETIMEDOUT : urb->status;
} else
status = urb->status;
out:
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_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) {
int interval;
if (usb_dev->speed == USB_SPEED_HIGH)
interval = 1 << min(15, ep->desc.bInterval - 1);
else
interval = ep->desc.bInterval;
pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
usb_fill_int_urb(urb, usb_dev, pipe, data, len,
usb_api_blocking_completion, NULL, interval);
} 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;
}
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
static void sg_complete (struct urb *urb)
{
struct usb_sg_request *io = 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 != -ENODEV
&& 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,
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;
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], 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;
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.
*/
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;
}
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.
*
* @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);
}
[PATCH] USB: Consider power budget when choosing configuration This patch (as609) changes the way we keep track of power budgeting for USB hubs and devices, and it updates the choose_configuration routine to take this information into account. (This is something we should have been doing all along.) A new field in struct usb_device holds the amount of bus current available from the upstream port, and the usb_hub structure keeps track of the current available for each downstream port. Two new rules for configuration selection are added: Don't select a self-powered configuration when only bus power is available. Don't select a configuration requiring more bus power than is available. However the first rule is #if-ed out, because I found that the internal hub in my HP USB keyboard claims that its only configuration is self-powered. The rule would prevent the configuration from being chosen, leaving the hub & keyboard unconfigured. Since similar descriptor errors may turn out to be fairly common, it seemed wise not to include a rule that would break automatic configuration unnecessarily for such devices. The second rule may also trigger unnecessarily, although this should be less common. More likely it will annoy people by sometimes failing to accept configurations that should never have been chosen in the first place. The patch also changes usbcore's reaction when no configuration is suitable. Instead of raising an error and rejecting the device, now the core will simply leave the device unconfigured. People can always work around such problems by installing configurations manually through sysfs. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-11-23 17:03:12 +00:00
/* 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;
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);
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);