1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
/*
* miscellaneous helper functions
*
* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
* Licensed under the terms of the GNU General Public License, version 2.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/firewire.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "lib.h"
#define ERROR_RETRY_DELAY_MS 20
/**
* snd_fw_transaction - send a request and wait for its completion
* @unit: the driver's unit on the target device
* @tcode: the transaction code
* @offset: the address in the target's address space
* @buffer: input/output data
* @length: length of @buffer
* @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the
* request only in that generation; use %FW_QUIET to suppress error
* messages
*
* Submits an asynchronous request to the target device, and waits for the
* response. The node ID and the current generation are derived from @unit.
* On a bus reset or an error, the transaction is retried a few times.
* Returns zero on success, or a negative error code.
*/
int snd_fw_transaction(struct fw_unit *unit, int tcode,
u64 offset, void *buffer, size_t length,
unsigned int flags)
{
struct fw_device *device = fw_parent_device(unit);
int generation, rcode, tries = 0;
generation = flags & FW_GENERATION_MASK;
for (;;) {
if (!(flags & FW_FIXED_GENERATION)) {
generation = device->generation;
smp_rmb(); /* node_id vs. generation */
}
rcode = fw_run_transaction(device->card, tcode,
device->node_id, generation,
device->max_speed, offset,
buffer, length);
if (rcode == RCODE_COMPLETE)
return 0;
if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
return -EAGAIN;
if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
if (!(flags & FW_QUIET))
dev_err(&unit->device,
"transaction failed: %s\n",
fw_rcode_string(rcode));
return -EIO;
}
msleep(ERROR_RETRY_DELAY_MS);
}
}
EXPORT_SYMBOL(snd_fw_transaction);
static void async_midi_port_callback(struct fw_card *card, int rcode,
void *data, size_t length,
void *callback_data)
{
struct snd_fw_async_midi_port *port = callback_data;
struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
if (rcode == RCODE_COMPLETE && substream != NULL)
snd_rawmidi_transmit_ack(substream, port->consume_bytes);
}
static void midi_port_work(struct work_struct *work)
{
struct snd_fw_async_midi_port *port =
container_of(work, struct snd_fw_async_midi_port, work);
struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
int generation;
int type;
/* Nothing to do. */
if (substream == NULL || snd_rawmidi_transmit_empty(substream))
return;
/*
* Fill the buffer. The callee must use snd_rawmidi_transmit_peek().
* Later, snd_rawmidi_transmit_ack() is called.
*/
memset(port->buf, 0, port->len);
port->consume_bytes = port->fill(substream, port->buf);
if (port->consume_bytes <= 0) {
/* Do it in next chance, immediately. */
if (port->consume_bytes == 0)
schedule_work(&port->work);
return;
}
/* Calculate type of transaction. */
if (port->len == 4)
type = TCODE_WRITE_QUADLET_REQUEST;
else
type = TCODE_WRITE_BLOCK_REQUEST;
/* Start this transaction. */
/*
* In Linux FireWire core, when generation is updated with memory
* barrier, node id has already been updated. In this module, After
* this smp_rmb(), load/store instructions to memory are completed.
* Thus, both of generation and node id are available with recent
* values. This is a light-serialization solution to handle bus reset
* events on IEEE 1394 bus.
*/
generation = port->parent->generation;
smp_rmb();
fw_send_request(port->parent->card, &port->transaction, type,
port->parent->node_id, generation,
port->parent->max_speed, port->addr,
port->buf, port->len, async_midi_port_callback,
port);
}
/**
* snd_fw_async_midi_port_init - initialize asynchronous MIDI port structure
* @port: the asynchronous MIDI port to initialize
* @unit: the target of the asynchronous transaction
* @addr: the address to which transactions are transferred
* @len: the length of transaction
* @fill: the callback function to fill given buffer, and returns the
* number of consumed bytes for MIDI message.
*
*/
int snd_fw_async_midi_port_init(struct snd_fw_async_midi_port *port,
struct fw_unit *unit, u64 addr, unsigned int len,
snd_fw_async_midi_port_fill fill)
{
port->len = DIV_ROUND_UP(len, 4) * 4;
port->buf = kzalloc(port->len, GFP_KERNEL);
if (port->buf == NULL)
return -ENOMEM;
port->parent = fw_parent_device(unit);
port->addr = addr;
port->fill = fill;
INIT_WORK(&port->work, midi_port_work);
return 0;
}
EXPORT_SYMBOL(snd_fw_async_midi_port_init);
/**
* snd_fw_async_midi_port_destroy - free asynchronous MIDI port structure
* @port: the asynchronous MIDI port structure
*/
void snd_fw_async_midi_port_destroy(struct snd_fw_async_midi_port *port)
{
snd_fw_async_midi_port_finish(port);
cancel_work_sync(&port->work);
kfree(port->buf);
}
EXPORT_SYMBOL(snd_fw_async_midi_port_destroy);
MODULE_DESCRIPTION("FireWire audio helper functions");
MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
MODULE_LICENSE("GPL v2");
|
