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// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * miscellaneous helper functions
 4 *
 5 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
 
 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
70MODULE_DESCRIPTION("FireWire audio helper functions");
71MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
72MODULE_LICENSE("GPL");