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1/*
2 * miscellaneous helper functions
3 *
4 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
5 * Licensed under the terms of the GNU General Public License, version 2.
6 */
7
8#include <linux/delay.h>
9#include <linux/device.h>
10#include <linux/firewire.h>
11#include <linux/module.h>
12#include "lib.h"
13
14#define ERROR_RETRY_DELAY_MS 20
15
16/**
17 * snd_fw_transaction - send a request and wait for its completion
18 * @unit: the driver's unit on the target device
19 * @tcode: the transaction code
20 * @offset: the address in the target's address space
21 * @buffer: input/output data
22 * @length: length of @buffer
23 * @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the
24 * request only in that generation; use %FW_QUIET to suppress error
25 * messages
26 *
27 * Submits an asynchronous request to the target device, and waits for the
28 * response. The node ID and the current generation are derived from @unit.
29 * On a bus reset or an error, the transaction is retried a few times.
30 * Returns zero on success, or a negative error code.
31 */
32int snd_fw_transaction(struct fw_unit *unit, int tcode,
33 u64 offset, void *buffer, size_t length,
34 unsigned int flags)
35{
36 struct fw_device *device = fw_parent_device(unit);
37 int generation, rcode, tries = 0;
38
39 generation = flags & FW_GENERATION_MASK;
40 for (;;) {
41 if (!(flags & FW_FIXED_GENERATION)) {
42 generation = device->generation;
43 smp_rmb(); /* node_id vs. generation */
44 }
45 rcode = fw_run_transaction(device->card, tcode,
46 device->node_id, generation,
47 device->max_speed, offset,
48 buffer, length);
49
50 if (rcode == RCODE_COMPLETE)
51 return 0;
52
53 if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
54 return -EAGAIN;
55
56 if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
57 if (!(flags & FW_QUIET))
58 dev_err(&unit->device,
59 "transaction failed: %s\n",
60 fw_rcode_string(rcode));
61 return -EIO;
62 }
63
64 msleep(ERROR_RETRY_DELAY_MS);
65 }
66}
67EXPORT_SYMBOL(snd_fw_transaction);
68
69MODULE_DESCRIPTION("FireWire audio helper functions");
70MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
71MODULE_LICENSE("GPL v2");
1/*
2 * miscellaneous helper functions
3 *
4 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
5 * Licensed under the terms of the GNU General Public License, version 2.
6 */
7
8#include <linux/delay.h>
9#include <linux/device.h>
10#include <linux/firewire.h>
11#include <linux/module.h>
12#include <linux/slab.h>
13#include "lib.h"
14
15#define ERROR_RETRY_DELAY_MS 20
16
17/**
18 * snd_fw_transaction - send a request and wait for its completion
19 * @unit: the driver's unit on the target device
20 * @tcode: the transaction code
21 * @offset: the address in the target's address space
22 * @buffer: input/output data
23 * @length: length of @buffer
24 * @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the
25 * request only in that generation; use %FW_QUIET to suppress error
26 * messages
27 *
28 * Submits an asynchronous request to the target device, and waits for the
29 * response. The node ID and the current generation are derived from @unit.
30 * On a bus reset or an error, the transaction is retried a few times.
31 * Returns zero on success, or a negative error code.
32 */
33int snd_fw_transaction(struct fw_unit *unit, int tcode,
34 u64 offset, void *buffer, size_t length,
35 unsigned int flags)
36{
37 struct fw_device *device = fw_parent_device(unit);
38 int generation, rcode, tries = 0;
39
40 generation = flags & FW_GENERATION_MASK;
41 for (;;) {
42 if (!(flags & FW_FIXED_GENERATION)) {
43 generation = device->generation;
44 smp_rmb(); /* node_id vs. generation */
45 }
46 rcode = fw_run_transaction(device->card, tcode,
47 device->node_id, generation,
48 device->max_speed, offset,
49 buffer, length);
50
51 if (rcode == RCODE_COMPLETE)
52 return 0;
53
54 if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
55 return -EAGAIN;
56
57 if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
58 if (!(flags & FW_QUIET))
59 dev_err(&unit->device,
60 "transaction failed: %s\n",
61 fw_rcode_string(rcode));
62 return -EIO;
63 }
64
65 msleep(ERROR_RETRY_DELAY_MS);
66 }
67}
68EXPORT_SYMBOL(snd_fw_transaction);
69
70#define PROBE_DELAY_MS (2 * MSEC_PER_SEC)
71
72/**
73 * snd_fw_schedule_registration - schedule work for sound card registration
74 * @unit: an instance for unit on IEEE 1394 bus
75 * @dwork: delayed work with callback function
76 *
77 * This function is not designed for general purposes. When new unit is
78 * connected to IEEE 1394 bus, the bus is under bus-reset state because of
79 * topological change. In this state, units tend to fail both of asynchronous
80 * and isochronous communication. To avoid this problem, this function is used
81 * to postpone sound card registration after the state. The callers must
82 * set up instance of delayed work in advance.
83 */
84void snd_fw_schedule_registration(struct fw_unit *unit,
85 struct delayed_work *dwork)
86{
87 u64 now, delay;
88
89 now = get_jiffies_64();
90 delay = fw_parent_device(unit)->card->reset_jiffies
91 + msecs_to_jiffies(PROBE_DELAY_MS);
92
93 if (time_after64(delay, now))
94 delay -= now;
95 else
96 delay = 0;
97
98 mod_delayed_work(system_wq, dwork, delay);
99}
100EXPORT_SYMBOL(snd_fw_schedule_registration);
101
102static void async_midi_port_callback(struct fw_card *card, int rcode,
103 void *data, size_t length,
104 void *callback_data)
105{
106 struct snd_fw_async_midi_port *port = callback_data;
107 struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
108
109 /* This port is closed. */
110 if (substream == NULL)
111 return;
112
113 if (rcode == RCODE_COMPLETE)
114 snd_rawmidi_transmit_ack(substream, port->consume_bytes);
115 else if (!rcode_is_permanent_error(rcode))
116 /* To start next transaction immediately for recovery. */
117 port->next_ktime = 0;
118 else
119 /* Don't continue processing. */
120 port->error = true;
121
122 port->idling = true;
123
124 if (!snd_rawmidi_transmit_empty(substream))
125 schedule_work(&port->work);
126}
127
128static void midi_port_work(struct work_struct *work)
129{
130 struct snd_fw_async_midi_port *port =
131 container_of(work, struct snd_fw_async_midi_port, work);
132 struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
133 int generation;
134 int type;
135
136 /* Under transacting or error state. */
137 if (!port->idling || port->error)
138 return;
139
140 /* Nothing to do. */
141 if (substream == NULL || snd_rawmidi_transmit_empty(substream))
142 return;
143
144 /* Do it in next chance. */
145 if (ktime_after(port->next_ktime, ktime_get())) {
146 schedule_work(&port->work);
147 return;
148 }
149
150 /*
151 * Fill the buffer. The callee must use snd_rawmidi_transmit_peek().
152 * Later, snd_rawmidi_transmit_ack() is called.
153 */
154 memset(port->buf, 0, port->len);
155 port->consume_bytes = port->fill(substream, port->buf);
156 if (port->consume_bytes <= 0) {
157 /* Do it in next chance, immediately. */
158 if (port->consume_bytes == 0) {
159 port->next_ktime = 0;
160 schedule_work(&port->work);
161 } else {
162 /* Fatal error. */
163 port->error = true;
164 }
165 return;
166 }
167
168 /* Calculate type of transaction. */
169 if (port->len == 4)
170 type = TCODE_WRITE_QUADLET_REQUEST;
171 else
172 type = TCODE_WRITE_BLOCK_REQUEST;
173
174 /* Set interval to next transaction. */
175 port->next_ktime = ktime_add_ns(ktime_get(),
176 port->consume_bytes * 8 * NSEC_PER_SEC / 31250);
177
178 /* Start this transaction. */
179 port->idling = false;
180
181 /*
182 * In Linux FireWire core, when generation is updated with memory
183 * barrier, node id has already been updated. In this module, After
184 * this smp_rmb(), load/store instructions to memory are completed.
185 * Thus, both of generation and node id are available with recent
186 * values. This is a light-serialization solution to handle bus reset
187 * events on IEEE 1394 bus.
188 */
189 generation = port->parent->generation;
190 smp_rmb();
191
192 fw_send_request(port->parent->card, &port->transaction, type,
193 port->parent->node_id, generation,
194 port->parent->max_speed, port->addr,
195 port->buf, port->len, async_midi_port_callback,
196 port);
197}
198
199/**
200 * snd_fw_async_midi_port_init - initialize asynchronous MIDI port structure
201 * @port: the asynchronous MIDI port to initialize
202 * @unit: the target of the asynchronous transaction
203 * @addr: the address to which transactions are transferred
204 * @len: the length of transaction
205 * @fill: the callback function to fill given buffer, and returns the
206 * number of consumed bytes for MIDI message.
207 *
208 */
209int snd_fw_async_midi_port_init(struct snd_fw_async_midi_port *port,
210 struct fw_unit *unit, u64 addr, unsigned int len,
211 snd_fw_async_midi_port_fill fill)
212{
213 port->len = DIV_ROUND_UP(len, 4) * 4;
214 port->buf = kzalloc(port->len, GFP_KERNEL);
215 if (port->buf == NULL)
216 return -ENOMEM;
217
218 port->parent = fw_parent_device(unit);
219 port->addr = addr;
220 port->fill = fill;
221 port->idling = true;
222 port->next_ktime = 0;
223 port->error = false;
224
225 INIT_WORK(&port->work, midi_port_work);
226
227 return 0;
228}
229EXPORT_SYMBOL(snd_fw_async_midi_port_init);
230
231/**
232 * snd_fw_async_midi_port_destroy - free asynchronous MIDI port structure
233 * @port: the asynchronous MIDI port structure
234 */
235void snd_fw_async_midi_port_destroy(struct snd_fw_async_midi_port *port)
236{
237 snd_fw_async_midi_port_finish(port);
238 cancel_work_sync(&port->work);
239 kfree(port->buf);
240}
241EXPORT_SYMBOL(snd_fw_async_midi_port_destroy);
242
243MODULE_DESCRIPTION("FireWire audio helper functions");
244MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
245MODULE_LICENSE("GPL v2");