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-rw-r--r--sound/firewire/lib.c85
1 files changed, 85 insertions, 0 deletions
diff --git a/sound/firewire/lib.c b/sound/firewire/lib.c
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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 5
15
16/**
17 * rcode_string - convert a firewire result code to a string
18 * @rcode: the result
19 */
20const char *rcode_string(unsigned int rcode)
21{
22 static const char *const names[] = {
23 [RCODE_COMPLETE] = "complete",
24 [RCODE_CONFLICT_ERROR] = "conflict error",
25 [RCODE_DATA_ERROR] = "data error",
26 [RCODE_TYPE_ERROR] = "type error",
27 [RCODE_ADDRESS_ERROR] = "address error",
28 [RCODE_SEND_ERROR] = "send error",
29 [RCODE_CANCELLED] = "cancelled",
30 [RCODE_BUSY] = "busy",
31 [RCODE_GENERATION] = "generation",
32 [RCODE_NO_ACK] = "no ack",
33 };
34
35 if (rcode < ARRAY_SIZE(names) && names[rcode])
36 return names[rcode];
37 else
38 return "unknown";
39}
40EXPORT_SYMBOL(rcode_string);
41
42/**
43 * snd_fw_transaction - send a request and wait for its completion
44 * @unit: the driver's unit on the target device
45 * @tcode: the transaction code
46 * @offset: the address in the target's address space
47 * @buffer: input/output data
48 * @length: length of @buffer
49 *
50 * Submits an asynchronous request to the target device, and waits for the
51 * response. The node ID and the current generation are derived from @unit.
52 * On a bus reset or an error, the transaction is retried a few times.
53 * Returns zero on success, or a negative error code.
54 */
55int snd_fw_transaction(struct fw_unit *unit, int tcode,
56 u64 offset, void *buffer, size_t length)
57{
58 struct fw_device *device = fw_parent_device(unit);
59 int generation, rcode, tries = 0;
60
61 for (;;) {
62 generation = device->generation;
63 smp_rmb(); /* node_id vs. generation */
64 rcode = fw_run_transaction(device->card, tcode,
65 device->node_id, generation,
66 device->max_speed, offset,
67 buffer, length);
68
69 if (rcode == RCODE_COMPLETE)
70 return 0;
71
72 if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
73 dev_err(&unit->device, "transaction failed: %s\n",
74 rcode_string(rcode));
75 return -EIO;
76 }
77
78 msleep(ERROR_RETRY_DELAY_MS);
79 }
80}
81EXPORT_SYMBOL(snd_fw_transaction);
82
83MODULE_DESCRIPTION("FireWire audio helper functions");
84MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
85MODULE_LICENSE("GPL v2");