2 * miscellaneous helper functions
4 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
5 * Licensed under the terms of the GNU General Public License, version 2.
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>
15 #define ERROR_RETRY_DELAY_MS 20
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
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.
33 int snd_fw_transaction(struct fw_unit *unit, int tcode,
34 u64 offset, void *buffer, size_t length,
37 struct fw_device *device = fw_parent_device(unit);
38 int generation, rcode, tries = 0;
40 generation = flags & FW_GENERATION_MASK;
42 if (!(flags & FW_FIXED_GENERATION)) {
43 generation = device->generation;
44 smp_rmb(); /* node_id vs. generation */
46 rcode = fw_run_transaction(device->card, tcode,
47 device->node_id, generation,
48 device->max_speed, offset,
51 if (rcode == RCODE_COMPLETE)
54 if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
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));
65 msleep(ERROR_RETRY_DELAY_MS);
68 EXPORT_SYMBOL(snd_fw_transaction);
70 static void async_midi_port_callback(struct fw_card *card, int rcode,
71 void *data, size_t length,
74 struct snd_fw_async_midi_port *port = callback_data;
75 struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
77 if (rcode == RCODE_COMPLETE && substream != NULL)
78 snd_rawmidi_transmit_ack(substream, port->consume_bytes);
83 static void midi_port_work(struct work_struct *work)
85 struct snd_fw_async_midi_port *port =
86 container_of(work, struct snd_fw_async_midi_port, work);
87 struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
91 /* Under transacting. */
96 if (substream == NULL || snd_rawmidi_transmit_empty(substream))
100 * Fill the buffer. The callee must use snd_rawmidi_transmit_peek().
101 * Later, snd_rawmidi_transmit_ack() is called.
103 memset(port->buf, 0, port->len);
104 port->consume_bytes = port->fill(substream, port->buf);
105 if (port->consume_bytes <= 0) {
106 /* Do it in next chance, immediately. */
107 if (port->consume_bytes == 0)
108 schedule_work(&port->work);
112 /* Calculate type of transaction. */
114 type = TCODE_WRITE_QUADLET_REQUEST;
116 type = TCODE_WRITE_BLOCK_REQUEST;
118 /* Start this transaction. */
119 port->idling = false;
122 * In Linux FireWire core, when generation is updated with memory
123 * barrier, node id has already been updated. In this module, After
124 * this smp_rmb(), load/store instructions to memory are completed.
125 * Thus, both of generation and node id are available with recent
126 * values. This is a light-serialization solution to handle bus reset
127 * events on IEEE 1394 bus.
129 generation = port->parent->generation;
132 fw_send_request(port->parent->card, &port->transaction, type,
133 port->parent->node_id, generation,
134 port->parent->max_speed, port->addr,
135 port->buf, port->len, async_midi_port_callback,
140 * snd_fw_async_midi_port_init - initialize asynchronous MIDI port structure
141 * @port: the asynchronous MIDI port to initialize
142 * @unit: the target of the asynchronous transaction
143 * @addr: the address to which transactions are transferred
144 * @len: the length of transaction
145 * @fill: the callback function to fill given buffer, and returns the
146 * number of consumed bytes for MIDI message.
149 int snd_fw_async_midi_port_init(struct snd_fw_async_midi_port *port,
150 struct fw_unit *unit, u64 addr, unsigned int len,
151 snd_fw_async_midi_port_fill fill)
153 port->len = DIV_ROUND_UP(len, 4) * 4;
154 port->buf = kzalloc(port->len, GFP_KERNEL);
155 if (port->buf == NULL)
158 port->parent = fw_parent_device(unit);
163 INIT_WORK(&port->work, midi_port_work);
167 EXPORT_SYMBOL(snd_fw_async_midi_port_init);
170 * snd_fw_async_midi_port_destroy - free asynchronous MIDI port structure
171 * @port: the asynchronous MIDI port structure
173 void snd_fw_async_midi_port_destroy(struct snd_fw_async_midi_port *port)
175 snd_fw_async_midi_port_finish(port);
176 cancel_work_sync(&port->work);
179 EXPORT_SYMBOL(snd_fw_async_midi_port_destroy);
181 MODULE_DESCRIPTION("FireWire audio helper functions");
182 MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
183 MODULE_LICENSE("GPL v2");