source: mainline/uspace/drv/bus/usb/xhci/isoch.h@ 708d8fcd

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 708d8fcd was 708d8fcd, checked in by Ondřej Hlavatý <aearsis@…>, 8 years ago

xhci: rewritten isochronous transfers

There was a fundamental problem with relying on hardware to send
RING_OVERRUN/UNDERRUN events, which QEMU (and possibly others) do not
send. That resulted in not knowing if the transfer is still on schedule,
and having to ring the doorbell every time. That is not feasible,
because then the transfer can be more frequent than it should be.
Furthermore, it ignored the fact that isochronous TRBs are to be
scheduled not too late, but also not too soon (see 4.11.2.5 of the xHCI
spec).

Now, scheduling the TRBs to hardware is called feeding, and can be
delayed by setting a timer. Ring overruns/underruns are detected also at
the end of handling an event.

  • Property mode set to 100644
File size: 3.7 KB
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1/*
2 * Copyright (c) 2017 HelUSB3 team
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup drvusbxhci
30 * @{
31 */
32/** @file
33 * @brief Data structures and functions related to isochronous transfers.
34 */
35
36#ifndef XHCI_ISOCH_H
37#define XHCI_ISOCH_H
38
39#include <usb/host/dma_buffer.h>
40
41#include "trb_ring.h"
42
43#include "transfers.h"
44
45typedef struct xhci_endpoint xhci_endpoint_t;
46
47typedef enum {
48 ISOCH_EMPTY, /* Unused yet */
49 ISOCH_FILLED, /* The data buffer is valid */
50 ISOCH_FED, /* The data buffer is in possession of xHC */
51 ISOCH_COMPLETE, /* The error code is valid */
52} xhci_isoch_transfer_state_t;
53
54typedef struct {
55 /** Buffer with data */
56 dma_buffer_t data;
57 /** Used buffer size */
58 size_t size;
59
60 /** Current state */
61 xhci_isoch_transfer_state_t state;
62
63 /** Microframe to which to schedule */
64 uint32_t mfindex;
65
66 /** Physical address of enqueued TRB */
67 uintptr_t interrupt_trb_phys;
68
69 /** Result of the transfer. Valid only if status == ISOCH_COMPLETE. */
70 int error;
71} xhci_isoch_transfer_t;
72
73typedef struct {
74 /** Protects common buffers. */
75 fibril_mutex_t guard;
76
77 /** Signals filled buffer. */
78 fibril_condvar_t avail;
79
80 /** Defers handing buffers to the HC. */
81 fibril_timer_t *feeding_timer;
82
83 /** The maximum size of an isochronous transfer and therefore the size of buffers */
84 size_t max_size;
85
86 /** The MFINDEX at which the last TRB was scheduled. */
87 uint32_t last_mfindex;
88
89 /** Isochronous scheduled transfers with respective buffers */
90 #define XHCI_ISOCH_BUFFER_COUNT 4
91 xhci_isoch_transfer_t transfers[XHCI_ISOCH_BUFFER_COUNT];
92
93 /**
94 * Out: Next buffer that will be handed to HW.
95 * In: Invalid. Hidden inside HC.
96 */
97 size_t hw_enqueue;
98
99 /**
100 * Out: Next buffer that will be used for writing.
101 * In: Next buffer that will be enqueued to be written by the HC
102 */
103 size_t enqueue;
104
105 /**
106 * Out: First buffer that will be checked for completion
107 * In: Next buffer to be read from, when valid.
108 */
109 size_t dequeue;
110} xhci_isoch_t;
111
112typedef struct usb_endpoint_descriptors usb_endpoint_descriptors_t;
113
114void isoch_init(xhci_endpoint_t *, const usb_endpoint_descriptors_t *);
115void isoch_fini(xhci_endpoint_t *);
116int isoch_alloc_transfers(xhci_endpoint_t *);
117
118int isoch_schedule_out(xhci_transfer_t *);
119int isoch_schedule_in(xhci_transfer_t *);
120int isoch_handle_transfer_event(xhci_hc_t *, xhci_endpoint_t *, xhci_trb_t *);
121
122#endif
123
124/**
125 * @}
126 */
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