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 "lib.h"
13
14#define ERROR_RETRY_DELAY_MS	5
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 *
24 * Submits an asynchronous request to the target device, and waits for the
25 * response.  The node ID and the current generation are derived from @unit.
26 * On a bus reset or an error, the transaction is retried a few times.
27 * Returns zero on success, or a negative error code.
28 */
29int snd_fw_transaction(struct fw_unit *unit, int tcode,
30		       u64 offset, void *buffer, size_t length)
 
31{
32	struct fw_device *device = fw_parent_device(unit);
33	int generation, rcode, tries = 0;
34
 
35	for (;;) {
36		generation = device->generation;
37		smp_rmb(); /* node_id vs. generation */
 
 
38		rcode = fw_run_transaction(device->card, tcode,
39					   device->node_id, generation,
40					   device->max_speed, offset,
41					   buffer, length);
42
43		if (rcode == RCODE_COMPLETE)
44			return 0;
45
 
 
 
46		if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
47			dev_err(&unit->device, "transaction failed: %s\n",
48				fw_rcode_string(rcode));
 
 
49			return -EIO;
50		}
51
52		msleep(ERROR_RETRY_DELAY_MS);
53	}
54}
55EXPORT_SYMBOL(snd_fw_transaction);
56
57MODULE_DESCRIPTION("FireWire audio helper functions");
58MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
59MODULE_LICENSE("GPL v2");