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846 giacomo 1
#include <linuxcomp.h>
2
 
3
#include <linux/config.h>
4
#include <linux/module.h>
5
#include <linux/string.h>
6
#include <linux/bitops.h>
7
#include <linux/slab.h>
8
#include <linux/init.h>
9
 
10
#ifdef CONFIG_USB_DEBUG
11
        #define DEBUG
12
#else
13
        #undef DEBUG
14
#endif
15
#include <linux/usb.h>
16
#include "hcd.h"
17
 
18
/**
19
 * usb_init_urb - initializes a urb so that it can be used by a USB driver
20
 * @urb: pointer to the urb to initialize
21
 *
22
 * Initializes a urb so that the USB subsystem can use it properly.
23
 *
24
 * If a urb is created with a call to usb_alloc_urb() it is not
25
 * necessary to call this function.  Only use this if you allocate the
26
 * space for a struct urb on your own.  If you call this function, be
27
 * careful when freeing the memory for your urb that it is no longer in
28
 * use by the USB core.
29
 *
30
 * Only use this function if you _really_ understand what you are doing.
31
 */
32
void usb_init_urb(struct urb *urb)
33
{
34
        if (urb) {
35
                memset(urb, 0, sizeof(*urb));
36
                urb->count = (atomic_t)ATOMIC_INIT(1);
37
                spin_lock_init(&urb->lock);
38
        }
39
}
40
 
41
/**
42
 * usb_alloc_urb - creates a new urb for a USB driver to use
43
 * @iso_packets: number of iso packets for this urb
44
 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
45
 *      valid options for this.
46
 *
47
 * Creates an urb for the USB driver to use, initializes a few internal
48
 * structures, incrementes the usage counter, and returns a pointer to it.
49
 *
50
 * If no memory is available, NULL is returned.
51
 *
52
 * If the driver want to use this urb for interrupt, control, or bulk
53
 * endpoints, pass '0' as the number of iso packets.
54
 *
55
 * The driver must call usb_free_urb() when it is finished with the urb.
56
 */
57
struct urb *usb_alloc_urb(int iso_packets, int mem_flags)
58
{
59
        struct urb *urb;
60
 
61
        urb = (struct urb *)kmalloc(sizeof(struct urb) +
62
                iso_packets * sizeof(struct usb_iso_packet_descriptor),
63
                mem_flags);
64
        if (!urb) {
65
                err("alloc_urb: kmalloc failed");
66
                return NULL;
67
        }
68
        usb_init_urb(urb);
69
        return urb;
70
}
71
 
72
/**
73
 * usb_free_urb - frees the memory used by a urb when all users of it are finished
74
 * @urb: pointer to the urb to free
75
 *
76
 * Must be called when a user of a urb is finished with it.  When the last user
77
 * of the urb calls this function, the memory of the urb is freed.
78
 *
79
 * Note: The transfer buffer associated with the urb is not freed, that must be
80
 * done elsewhere.
81
 */
82
void usb_free_urb(struct urb *urb)
83
{
84
        if (urb)
85
                if (atomic_dec_and_test(&urb->count))
86
                        kfree(urb);
87
}
88
 
89
/**
90
 * usb_get_urb - increments the reference count of the urb
91
 * @urb: pointer to the urb to modify
92
 *
93
 * This must be  called whenever a urb is transferred from a device driver to a
94
 * host controller driver.  This allows proper reference counting to happen
95
 * for urbs.
96
 *
97
 * A pointer to the urb with the incremented reference counter is returned.
98
 */
99
struct urb * usb_get_urb(struct urb *urb)
100
{
101
        if (urb) {
102
                atomic_inc(&urb->count);
103
                return urb;
104
        } else
105
                return NULL;
106
}
107
 
108
 
109
/*-------------------------------------------------------------------*/
110
 
111
/**
112
 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
113
 * @urb: pointer to the urb describing the request
114
 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
115
 *      of valid options for this.
116
 *
117
 * This submits a transfer request, and transfers control of the URB
118
 * describing that request to the USB subsystem.  Request completion will
119
 * be indicated later, asynchronously, by calling the completion handler.
120
 * The three types of completion are success, error, and unlink
121
 * (also called "request cancellation").
122
 * URBs may be submitted in interrupt context.
123
 *
124
 * The caller must have correctly initialized the URB before submitting
125
 * it.  Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
126
 * available to ensure that most fields are correctly initialized, for
127
 * the particular kind of transfer, although they will not initialize
128
 * any transfer flags.
129
 *
130
 * Successful submissions return 0; otherwise this routine returns a
131
 * negative error number.  If the submission is successful, the complete()
132
 * callback from the urb will be called exactly once, when the USB core and
133
 * host controller driver are finished with the urb.  When the completion
134
 * function is called, control of the URB is returned to the device
135
 * driver which issued the request.  The completion handler may then
136
 * immediately free or reuse that URB.
137
 *
138
 * For control endpoints, the synchronous usb_control_msg() call is
139
 * often used (in non-interrupt context) instead of this call.
140
 * That is often used through convenience wrappers, for the requests
141
 * that are standardized in the USB 2.0 specification.  For bulk
142
 * endpoints, a synchronous usb_bulk_msg() call is available.
143
 *
144
 * Request Queuing:
145
 *
146
 * URBs may be submitted to endpoints before previous ones complete, to
147
 * minimize the impact of interrupt latencies and system overhead on data
148
 * throughput.  This is required for continuous isochronous data streams,
149
 * and may also be required for some kinds of interrupt transfers. Such
150
 * queueing also maximizes bandwidth utilization by letting USB controllers
151
 * start work on later requests before driver software has finished the
152
 * completion processing for earlier requests.
153
 *
154
 * Bulk and Isochronous URBs may always be queued.  At this writing, all
155
 * mainstream host controller drivers support queueing for control and
156
 * interrupt transfer requests.
157
 *
158
 * Reserved Bandwidth Transfers:
159
 *
160
 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
161
 * using the interval specified in the urb.  Submitting the first urb to
162
 * the endpoint reserves the bandwidth necessary to make those transfers.
163
 * If the USB subsystem can't allocate sufficient bandwidth to perform
164
 * the periodic request, submitting such a periodic request should fail.
165
 *
166
 * Device drivers must explicitly request that repetition, by ensuring that
167
 * some URB is always on the endpoint's queue (except possibly for short
168
 * periods during completion callacks).  When there is no longer an urb
169
 * queued, the endpoint's bandwidth reservation is canceled.  This means
170
 * drivers can use their completion handlers to ensure they keep bandwidth
171
 * they need, by reinitializing and resubmitting the just-completed urb
172
 * until the driver longer needs that periodic bandwidth.
173
 *
174
 * Memory Flags:
175
 *
176
 * The general rules for how to decide which mem_flags to use
177
 * are the same as for kmalloc.  There are four
178
 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
179
 * GFP_ATOMIC.
180
 *
181
 * GFP_NOFS is not ever used, as it has not been implemented yet.
182
 *
183
 * GFP_ATOMIC is used when
184
 *   (a) you are inside a completion handler, an interrupt, bottom half,
185
 *       tasklet or timer, or
186
 *   (b) you are holding a spinlock or rwlock (does not apply to
187
 *       semaphores), or
188
 *   (c) current->state != TASK_RUNNING, this is the case only after
189
 *       you've changed it.
190
 *
191
 * GFP_NOIO is used in the block io path and error handling of storage
192
 * devices.
193
 *
194
 * All other situations use GFP_KERNEL.
195
 *
196
 * Some more specific rules for mem_flags can be inferred, such as
197
 *  (1) start_xmit, timeout, and receive methods of network drivers must
198
 *      use GFP_ATOMIC (they are called with a spinlock held);
199
 *  (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
200
 *      called with a spinlock held);
201
 *  (3) If you use a kernel thread with a network driver you must use
202
 *      GFP_NOIO, unless (b) or (c) apply;
203
 *  (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
204
 *      apply or your are in a storage driver's block io path;
205
 *  (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
206
 *  (6) changing firmware on a running storage or net device uses
207
 *      GFP_NOIO, unless b) or c) apply
208
 *
209
 */
210
int usb_submit_urb(struct urb *urb, int mem_flags)
211
{
212
        int                     pipe, temp, max;
213
        struct usb_device       *dev;
214
        struct usb_operations   *op;
215
        int                     is_out;
216
 
217
        if (!urb || urb->hcpriv || !urb->complete)
218
                return -EINVAL;
219
        if (!(dev = urb->dev) ||
220
            (dev->state < USB_STATE_DEFAULT) ||
221
            (!dev->bus) || (dev->devnum <= 0))
222
                return -ENODEV;
223
        if (!(op = dev->bus->op) || !op->submit_urb)
224
                return -ENODEV;
225
 
226
        urb->status = -EINPROGRESS;
227
        urb->actual_length = 0;
228
        urb->bandwidth = 0;
229
 
230
        /* Lots of sanity checks, so HCDs can rely on clean data
231
         * and don't need to duplicate tests
232
         */
233
        pipe = urb->pipe;
234
        temp = usb_pipetype (pipe);
235
        is_out = usb_pipeout (pipe);
236
 
237
        if (!usb_pipecontrol (pipe) && dev->state < USB_STATE_CONFIGURED)
238
                return -ENODEV;
239
 
240
        /* (actually HCDs may need to duplicate this, endpoint might yet
241
         * stall due to queued bulk/intr transactions that complete after
242
         * we check)
243
         */
244
        if (usb_endpoint_halted (dev, usb_pipeendpoint (pipe), is_out))
245
                return -EPIPE;
246
 
247
        /* FIXME there should be a sharable lock protecting us against
248
         * config/altsetting changes and disconnects, kicking in here.
249
         * (here == before maxpacket, and eventually endpoint type,
250
         * checks get made.)
251
         */
252
 
253
        max = usb_maxpacket (dev, pipe, is_out);
254
        if (max <= 0) {
255
                dbg ("%s: bogus endpoint %d-%s on usb-%s-%s (bad maxpacket %d)",
256
                        __FUNCTION__,
257
                        usb_pipeendpoint (pipe), is_out ? "OUT" : "IN",
258
                        dev->bus->bus_name, dev->devpath,
259
                        max);
260
                return -EMSGSIZE;
261
        }
262
 
263
        /* periodic transfers limit size per frame/uframe,
264
         * but drivers only control those sizes for ISO.
265
         * while we're checking, initialize return status.
266
         */
267
        if (temp == PIPE_ISOCHRONOUS) {
268
                int     n, len;
269
 
270
                /* "high bandwidth" mode, 1-3 packets/uframe? */
271
                if (dev->speed == USB_SPEED_HIGH) {
272
                        int     mult = 1 + ((max >> 11) & 0x03);
273
                        max &= 0x03ff;
274
                        max *= mult;
275
                }
276
 
277
                if (urb->number_of_packets <= 0)                   
278
                        return -EINVAL;
279
                for (n = 0; n < urb->number_of_packets; n++) {
280
                        len = urb->iso_frame_desc [n].length;
281
                        if (len < 0 || len > max)
282
                                return -EMSGSIZE;
283
                        urb->iso_frame_desc [n].status = -EXDEV;
284
                        urb->iso_frame_desc [n].actual_length = 0;
285
                }
286
        }
287
 
288
        /* the I/O buffer must be mapped/unmapped, except when length=0 */
289
        if (urb->transfer_buffer_length < 0)
290
                return -EMSGSIZE;
291
 
292
#ifdef DEBUG
293
        /* stuff that drivers shouldn't do, but which shouldn't
294
         * cause problems in HCDs if they get it wrong.
295
         */
296
        {
297
        unsigned int    orig_flags = urb->transfer_flags;
298
        unsigned int    allowed;
299
 
300
        /* enforce simple/standard policy */
301
        allowed = URB_ASYNC_UNLINK;     // affects later unlinks
302
        allowed |= (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP);
303
        allowed |= URB_NO_INTERRUPT;
304
        switch (temp) {
305
        case PIPE_BULK:
306
                if (is_out)
307
                        allowed |= URB_ZERO_PACKET;
308
                /* FALLTHROUGH */
309
        case PIPE_CONTROL:
310
                allowed |= URB_NO_FSBR; /* only affects UHCI */
311
                /* FALLTHROUGH */
312
        default:                        /* all non-iso endpoints */
313
                if (!is_out)
314
                        allowed |= URB_SHORT_NOT_OK;
315
                break;
316
        case PIPE_ISOCHRONOUS:
317
                allowed |= URB_ISO_ASAP;
318
                break;
319
        }
320
        urb->transfer_flags &= allowed;
321
 
322
        /* fail if submitter gave bogus flags */
323
        if (urb->transfer_flags != orig_flags) {
324
                err ("BOGUS urb flags, %x --> %x",
325
                        orig_flags, urb->transfer_flags);
326
                return -EINVAL;
327
        }
328
        }
329
#endif
330
        /*
331
         * Force periodic transfer intervals to be legal values that are
332
         * a power of two (so HCDs don't need to).
333
         *
334
         * FIXME want bus->{intr,iso}_sched_horizon values here.  Each HC
335
         * supports different values... this uses EHCI/UHCI defaults (and
336
         * EHCI can use smaller non-default values).
337
         */
338
        switch (temp) {
339
        case PIPE_ISOCHRONOUS:
340
        case PIPE_INTERRUPT:
341
                /* too small? */
342
                if (urb->interval <= 0)
343
                        return -EINVAL;
344
                /* too big? */
345
                switch (dev->speed) {
346
                case USB_SPEED_HIGH:    /* units are microframes */
347
                        // NOTE usb handles 2^15
348
                        if (urb->interval > (1024 * 8))
349
                                urb->interval = 1024 * 8;
350
                        temp = 1024 * 8;
351
                        break;
352
                case USB_SPEED_FULL:    /* units are frames/msec */
353
                case USB_SPEED_LOW:
354
                        if (temp == PIPE_INTERRUPT) {
355
                                if (urb->interval > 255)
356
                                        return -EINVAL;
357
                                // NOTE ohci only handles up to 32
358
                                temp = 128;
359
                        } else {
360
                                if (urb->interval > 1024)
361
                                        urb->interval = 1024;
362
                                // NOTE usb and ohci handle up to 2^15
363
                                temp = 1024;
364
                        }
365
                        break;
366
                default:
367
                        return -EINVAL;
368
                }
369
                /* power of two? */
370
                while (temp > urb->interval)
371
                        temp >>= 1;
372
                urb->interval = temp;
373
        }
374
 
375
        return op->submit_urb (urb, mem_flags);
376
}
377
 
378
/*-------------------------------------------------------------------*/
379
 
380
/**
381
 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
382
 * @urb: pointer to urb describing a previously submitted request
383
 *
384
 * This routine cancels an in-progress request.  URBs complete only
385
 * once per submission, and may be canceled only once per submission.
386
 * Successful cancelation means the requests's completion handler will
387
 * be called with a status code indicating that the request has been
388
 * canceled (rather than any other code) and will quickly be removed
389
 * from host controller data structures.
390
 *
391
 * When the URB_ASYNC_UNLINK transfer flag for the URB is clear, this
392
 * request is synchronous.  Success is indicated by returning zero,
393
 * at which time the urb will have been unlinked and its completion
394
 * handler will have been called with urb->status -ENOENT.  Failure is
395
 * indicated by any other return value.
396
 *
397
 * The synchronous cancelation mode may not be used
398
 * when unlinking an urb from an interrupt context, such as a bottom
399
 * half or a completion handler; or when holding a spinlock; or in
400
 * other cases when the caller can't schedule().
401
 *
402
 * When the URB_ASYNC_UNLINK transfer flag for the URB is set, this
403
 * request is asynchronous.  Success is indicated by returning -EINPROGRESS,
404
 * at which time the urb will normally not have been unlinked.
405
 * The completion function will see urb->status -ECONNRESET.  Failure
406
 * is indicated by any other return value.
407
 */
408
int usb_unlink_urb(struct urb *urb)
409
{
410
        if (urb && urb->dev && urb->dev->bus && urb->dev->bus->op)
411
                return urb->dev->bus->op->unlink_urb(urb);
412
        else
413
                return -ENODEV;
414
}
415
 
416
EXPORT_SYMBOL(usb_init_urb);
417
EXPORT_SYMBOL(usb_alloc_urb);
418
EXPORT_SYMBOL(usb_free_urb);
419
EXPORT_SYMBOL(usb_get_urb);
420
EXPORT_SYMBOL(usb_submit_urb);
421
EXPORT_SYMBOL(usb_unlink_urb);
422