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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 | */ |
20 | const 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 | } |
40 | EXPORT_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 | */ |
55 | int 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 | } |
81 | EXPORT_SYMBOL(snd_fw_transaction); |
82 | |
83 | MODULE_DESCRIPTION("FireWire audio helper functions"); |
84 | MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>"); |
85 | MODULE_LICENSE("GPL v2"); |
86 |
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v2.6.34-rc5
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