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#include <linuxcomp.h>

#include <linux/config.h>

#include <linux/module.h>

#include <linux/string.h>

#include <linux/bitops.h>

#include <linux/slab.h>

#include <linux/init.h>

#ifdef CONFIG_USB_DEBUG

        #define DEBUG

#else

        #undef DEBUG

#endif

#include <linux/usb.h>

#include "hcd.h"

/**

 * usb_init_urb - initializes a urb so that it can be used by a USB driver

 * @urb: pointer to the urb to initialize

 *

 * Initializes a urb so that the USB subsystem can use it properly.

 *

 * If a urb is created with a call to usb_alloc_urb() it is not

 * necessary to call this function.  Only use this if you allocate the

 * space for a struct urb on your own.  If you call this function, be

 * careful when freeing the memory for your urb that it is no longer in

 * use by the USB core.

 *

 * Only use this function if you _really_ understand what you are doing.

 */

void usb_init_urb(struct urb *urb)

{

        if (urb) {

                memset(urb, 0, sizeof(*urb));

                urb->count = (atomic_t)ATOMIC_INIT(1);

                spin_lock_init(&urb->lock);

        }

}

/**

 * usb_alloc_urb - creates a new urb for a USB driver to use

 * @iso_packets: number of iso packets for this urb

 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of

 *      valid options for this.

 *

 * Creates an urb for the USB driver to use, initializes a few internal

 * structures, incrementes the usage counter, and returns a pointer to it.

 *

 * If no memory is available, NULL is returned.

 *

 * If the driver want to use this urb for interrupt, control, or bulk

 * endpoints, pass '0' as the number of iso packets.

 *

 * The driver must call usb_free_urb() when it is finished with the urb.

 */

struct urb *usb_alloc_urb(int iso_packets, int mem_flags)

{

        struct urb *urb;

        urb = (struct urb *)kmalloc(sizeof(struct urb) +

                iso_packets * sizeof(struct usb_iso_packet_descriptor),

                mem_flags);

        if (!urb) {

                err("alloc_urb: kmalloc failed");

                return NULL;

        }

        usb_init_urb(urb);

        return urb;

}

/**

 * usb_free_urb - frees the memory used by a urb when all users of it are finished

 * @urb: pointer to the urb to free

 *

 * Must be called when a user of a urb is finished with it.  When the last user

 * of the urb calls this function, the memory of the urb is freed.

 *

 * Note: The transfer buffer associated with the urb is not freed, that must be

 * done elsewhere.

 */

void usb_free_urb(struct urb *urb)

{

        if (urb)

                if (atomic_dec_and_test(&urb->count))

                        kfree(urb);

}

/**

 * usb_get_urb - increments the reference count of the urb

 * @urb: pointer to the urb to modify

 *

 * This must be  called whenever a urb is transferred from a device driver to a

 * host controller driver.  This allows proper reference counting to happen

 * for urbs.

 *

 * A pointer to the urb with the incremented reference counter is returned.

 */

struct urb * usb_get_urb(struct urb *urb)

{

        if (urb) {

                atomic_inc(&urb->count);

                return urb;

        } else

                return NULL;

}

/*-------------------------------------------------------------------*/

/**

 * usb_submit_urb - issue an asynchronous transfer request for an endpoint

 * @urb: pointer to the urb describing the request

 * @mem_flags: the type of memory to allocate, see kmalloc() for a list

 *      of valid options for this.

 *

 * This submits a transfer request, and transfers control of the URB

 * describing that request to the USB subsystem.  Request completion will

 * be indicated later, asynchronously, by calling the completion handler.

 * The three types of completion are success, error, and unlink

 * (also called "request cancellation").

 * URBs may be submitted in interrupt context.

 *

 * The caller must have correctly initialized the URB before submitting

 * it.  Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are

 * available to ensure that most fields are correctly initialized, for

 * the particular kind of transfer, although they will not initialize

 * any transfer flags.

 *

 * Successful submissions return 0; otherwise this routine returns a

 * negative error number.  If the submission is successful, the complete()

 * callback from the urb will be called exactly once, when the USB core and

 * host controller driver are finished with the urb.  When the completion

 * function is called, control of the URB is returned to the device

 * driver which issued the request.  The completion handler may then

 * immediately free or reuse that URB.

 *

 * For control endpoints, the synchronous usb_control_msg() call is

 * often used (in non-interrupt context) instead of this call.

 * That is often used through convenience wrappers, for the requests

 * that are standardized in the USB 2.0 specification.  For bulk

 * endpoints, a synchronous usb_bulk_msg() call is available.

 *

 * Request Queuing:

 *

 * URBs may be submitted to endpoints before previous ones complete, to

 * minimize the impact of interrupt latencies and system overhead on data

 * throughput.  This is required for continuous isochronous data streams,

 * and may also be required for some kinds of interrupt transfers. Such

 * queueing also maximizes bandwidth utilization by letting USB controllers

 * start work on later requests before driver software has finished the

 * completion processing for earlier requests.

 *

 * Bulk and Isochronous URBs may always be queued.  At this writing, all

 * mainstream host controller drivers support queueing for control and

 * interrupt transfer requests.

 *

 * Reserved Bandwidth Transfers:

 *

 * Periodic transfers (interrupt or isochronous) are performed repeatedly,

 * using the interval specified in the urb.  Submitting the first urb to

 * the endpoint reserves the bandwidth necessary to make those transfers.

 * If the USB subsystem can't allocate sufficient bandwidth to perform

 * the periodic request, submitting such a periodic request should fail.

 *

 * Device drivers must explicitly request that repetition, by ensuring that

 * some URB is always on the endpoint's queue (except possibly for short

 * periods during completion callacks).  When there is no longer an urb

 * queued, the endpoint's bandwidth reservation is canceled.  This means

 * drivers can use their completion handlers to ensure they keep bandwidth

 * they need, by reinitializing and resubmitting the just-completed urb

 * until the driver longer needs that periodic bandwidth.

 *

 * Memory Flags:

 *

 * The general rules for how to decide which mem_flags to use

 * are the same as for kmalloc.  There are four

 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and

 * GFP_ATOMIC.

 *

 * GFP_NOFS is not ever used, as it has not been implemented yet.

 *

 * GFP_ATOMIC is used when

 *   (a) you are inside a completion handler, an interrupt, bottom half,

 *       tasklet or timer, or

 *   (b) you are holding a spinlock or rwlock (does not apply to

 *       semaphores), or

 *   (c) current->state != TASK_RUNNING, this is the case only after

 *       you've changed it.

 *

 * GFP_NOIO is used in the block io path and error handling of storage

 * devices.

 *

 * All other situations use GFP_KERNEL.

 *

 * Some more specific rules for mem_flags can be inferred, such as

 *  (1) start_xmit, timeout, and receive methods of network drivers must

 *      use GFP_ATOMIC (they are called with a spinlock held);

 *  (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also

 *      called with a spinlock held);

 *  (3) If you use a kernel thread with a network driver you must use

 *      GFP_NOIO, unless (b) or (c) apply;

 *  (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)

 *      apply or your are in a storage driver's block io path;

 *  (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and

 *  (6) changing firmware on a running storage or net device uses

 *      GFP_NOIO, unless b) or c) apply

 *

 */

int usb_submit_urb(struct urb *urb, int mem_flags)

{

        int                     pipe, temp, max;

        struct usb_device       *dev;

        struct usb_operations   *op;

        int                     is_out;

        if (!urb || urb->hcpriv || !urb->complete)

                return -EINVAL;

        if (!(dev = urb->dev) ||

            (dev->state < USB_STATE_DEFAULT) ||

            (!dev->bus) || (dev->devnum <= 0))

                return -ENODEV;

        if (!(op = dev->bus->op) || !op->submit_urb)

                return -ENODEV;

        urb->status = -EINPROGRESS;

        urb->actual_length = 0;

        urb->bandwidth = 0;

        /* Lots of sanity checks, so HCDs can rely on clean data

         * and don't need to duplicate tests

         */

        pipe = urb->pipe;

        temp = usb_pipetype (pipe);

        is_out = usb_pipeout (pipe);

        if (!usb_pipecontrol (pipe) && dev->state < USB_STATE_CONFIGURED)

                return -ENODEV;

        /* (actually HCDs may need to duplicate this, endpoint might yet

         * stall due to queued bulk/intr transactions that complete after

         * we check)

         */

        if (usb_endpoint_halted (dev, usb_pipeendpoint (pipe), is_out))

                return -EPIPE;

        /* FIXME there should be a sharable lock protecting us against

         * config/altsetting changes and disconnects, kicking in here.

         * (here == before maxpacket, and eventually endpoint type,

         * checks get made.)

         */

        max = usb_maxpacket (dev, pipe, is_out);

        if (max <= 0) {

                dbg ("%s: bogus endpoint %d-%s on usb-%s-%s (bad maxpacket %d)",

                        __FUNCTION__,

                        usb_pipeendpoint (pipe), is_out ? "OUT" : "IN",

                        dev->bus->bus_name, dev->devpath,

                        max);

                return -EMSGSIZE;

        }

        /* periodic transfers limit size per frame/uframe,

         * but drivers only control those sizes for ISO.

         * while we're checking, initialize return status.

         */

        if (temp == PIPE_ISOCHRONOUS) {

                int     n, len;

                /* "high bandwidth" mode, 1-3 packets/uframe? */

                if (dev->speed == USB_SPEED_HIGH) {

                        int     mult = 1 + ((max >> 11) & 0x03);

                        max &= 0x03ff;

                        max *= mult;

                }

                if (urb->number_of_packets <= 0)                   

                        return -EINVAL;

                for (n = 0; n < urb->number_of_packets; n++) {

                        len = urb->iso_frame_desc [n].length;

                        if (len < 0 || len > max)

                                return -EMSGSIZE;

                        urb->iso_frame_desc [n].status = -EXDEV;

                        urb->iso_frame_desc [n].actual_length = 0;

                }

        }

        /* the I/O buffer must be mapped/unmapped, except when length=0 */

        if (urb->transfer_buffer_length < 0)

                return -EMSGSIZE;

#ifdef DEBUG

        /* stuff that drivers shouldn't do, but which shouldn't

         * cause problems in HCDs if they get it wrong.

         */

        {

        unsigned int    orig_flags = urb->transfer_flags;

        unsigned int    allowed;

        /* enforce simple/standard policy */

        allowed = URB_ASYNC_UNLINK;     // affects later unlinks

        allowed |= (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP);

        allowed |= URB_NO_INTERRUPT;

        switch (temp) {

        case PIPE_BULK:

                if (is_out)

                        allowed |= URB_ZERO_PACKET;

                /* FALLTHROUGH */

        case PIPE_CONTROL:

                allowed |= URB_NO_FSBR; /* only affects UHCI */

                /* FALLTHROUGH */

        default:                        /* all non-iso endpoints */

                if (!is_out)

                        allowed |= URB_SHORT_NOT_OK;

                break;

        case PIPE_ISOCHRONOUS:

                allowed |= URB_ISO_ASAP;

                break;

        }

        urb->transfer_flags &= allowed;

        /* fail if submitter gave bogus flags */

        if (urb->transfer_flags != orig_flags) {

                err ("BOGUS urb flags, %x --> %x",

                        orig_flags, urb->transfer_flags);

                return -EINVAL;

        }

        }

#endif

        /*

         * Force periodic transfer intervals to be legal values that are

         * a power of two (so HCDs don't need to).

         *

         * FIXME want bus->{intr,iso}_sched_horizon values here.  Each HC

         * supports different values... this uses EHCI/UHCI defaults (and

         * EHCI can use smaller non-default values).

         */

        switch (temp) {

        case PIPE_ISOCHRONOUS:

        case PIPE_INTERRUPT:

                /* too small? */

                if (urb->interval <= 0)

                        return -EINVAL;

                /* too big? */

                switch (dev->speed) {

                case USB_SPEED_HIGH:    /* units are microframes */

                        // NOTE usb handles 2^15

                        if (urb->interval > (1024 * 8))

                                urb->interval = 1024 * 8;

                        temp = 1024 * 8;

                        break;

                case USB_SPEED_FULL:    /* units are frames/msec */

                case USB_SPEED_LOW:

                        if (temp == PIPE_INTERRUPT) {

                                if (urb->interval > 255)

                                        return -EINVAL;

                                // NOTE ohci only handles up to 32

                                temp = 128;

                        } else {

                                if (urb->interval > 1024)

                                        urb->interval = 1024;

                                // NOTE usb and ohci handle up to 2^15

                                temp = 1024;

                        }

                        break;

                default:

                        return -EINVAL;

                }

                /* power of two? */

                while (temp > urb->interval)

                        temp >>= 1;

                urb->interval = temp;

        }

        return op->submit_urb (urb, mem_flags);

}

/*-------------------------------------------------------------------*/

/**

 * usb_unlink_urb - abort/cancel a transfer request for an endpoint

 * @urb: pointer to urb describing a previously submitted request

 *

 * This routine cancels an in-progress request.  URBs complete only

 * once per submission, and may be canceled only once per submission.

 * Successful cancelation means the requests's completion handler will

 * be called with a status code indicating that the request has been

 * canceled (rather than any other code) and will quickly be removed

 * from host controller data structures.

 *

 * When the URB_ASYNC_UNLINK transfer flag for the URB is clear, this

 * request is synchronous.  Success is indicated by returning zero,

 * at which time the urb will have been unlinked and its completion

 * handler will have been called with urb->status -ENOENT.  Failure is

 * indicated by any other return value.

 *

 * The synchronous cancelation mode may not be used

 * when unlinking an urb from an interrupt context, such as a bottom

 * half or a completion handler; or when holding a spinlock; or in

 * other cases when the caller can't schedule().

 *

 * When the URB_ASYNC_UNLINK transfer flag for the URB is set, this

 * request is asynchronous.  Success is indicated by returning -EINPROGRESS,

 * at which time the urb will normally not have been unlinked.

 * The completion function will see urb->status -ECONNRESET.  Failure

 * is indicated by any other return value.

 */

int usb_unlink_urb(struct urb *urb)

{

        if (urb && urb->dev && urb->dev->bus && urb->dev->bus->op)

                return urb->dev->bus->op->unlink_urb(urb);

        else

                return -ENODEV;

}

EXPORT_SYMBOL(usb_init_urb);

EXPORT_SYMBOL(usb_alloc_urb);

EXPORT_SYMBOL(usb_free_urb);

EXPORT_SYMBOL(usb_get_urb);

EXPORT_SYMBOL(usb_submit_urb);

EXPORT_SYMBOL(usb_unlink_urb);