105 строки
3.1 KiB
C
105 строки
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* miscellaneous helper functions
|
|
*
|
|
* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
|
|
*/
|
|
|
|
#include <linux/delay.h>
|
|
#include <linux/device.h>
|
|
#include <linux/firewire.h>
|
|
#include <linux/module.h>
|
|
#include <linux/slab.h>
|
|
#include "lib.h"
|
|
|
|
#define ERROR_RETRY_DELAY_MS 20
|
|
|
|
/**
|
|
* snd_fw_transaction - send a request and wait for its completion
|
|
* @unit: the driver's unit on the target device
|
|
* @tcode: the transaction code
|
|
* @offset: the address in the target's address space
|
|
* @buffer: input/output data
|
|
* @length: length of @buffer
|
|
* @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the
|
|
* request only in that generation; use %FW_QUIET to suppress error
|
|
* messages
|
|
*
|
|
* Submits an asynchronous request to the target device, and waits for the
|
|
* response. The node ID and the current generation are derived from @unit.
|
|
* On a bus reset or an error, the transaction is retried a few times.
|
|
* Returns zero on success, or a negative error code.
|
|
*/
|
|
int snd_fw_transaction(struct fw_unit *unit, int tcode,
|
|
u64 offset, void *buffer, size_t length,
|
|
unsigned int flags)
|
|
{
|
|
struct fw_device *device = fw_parent_device(unit);
|
|
int generation, rcode, tries = 0;
|
|
|
|
generation = flags & FW_GENERATION_MASK;
|
|
for (;;) {
|
|
if (!(flags & FW_FIXED_GENERATION)) {
|
|
generation = device->generation;
|
|
smp_rmb(); /* node_id vs. generation */
|
|
}
|
|
rcode = fw_run_transaction(device->card, tcode,
|
|
device->node_id, generation,
|
|
device->max_speed, offset,
|
|
buffer, length);
|
|
|
|
if (rcode == RCODE_COMPLETE)
|
|
return 0;
|
|
|
|
if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
|
|
return -EAGAIN;
|
|
|
|
if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
|
|
if (!(flags & FW_QUIET))
|
|
dev_err(&unit->device,
|
|
"transaction failed: %s\n",
|
|
fw_rcode_string(rcode));
|
|
return -EIO;
|
|
}
|
|
|
|
msleep(ERROR_RETRY_DELAY_MS);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(snd_fw_transaction);
|
|
|
|
#define PROBE_DELAY_MS (2 * MSEC_PER_SEC)
|
|
|
|
/**
|
|
* snd_fw_schedule_registration - schedule work for sound card registration
|
|
* @unit: an instance for unit on IEEE 1394 bus
|
|
* @dwork: delayed work with callback function
|
|
*
|
|
* This function is not designed for general purposes. When new unit is
|
|
* connected to IEEE 1394 bus, the bus is under bus-reset state because of
|
|
* topological change. In this state, units tend to fail both of asynchronous
|
|
* and isochronous communication. To avoid this problem, this function is used
|
|
* to postpone sound card registration after the state. The callers must
|
|
* set up instance of delayed work in advance.
|
|
*/
|
|
void snd_fw_schedule_registration(struct fw_unit *unit,
|
|
struct delayed_work *dwork)
|
|
{
|
|
u64 now, delay;
|
|
|
|
now = get_jiffies_64();
|
|
delay = fw_parent_device(unit)->card->reset_jiffies
|
|
+ msecs_to_jiffies(PROBE_DELAY_MS);
|
|
|
|
if (time_after64(delay, now))
|
|
delay -= now;
|
|
else
|
|
delay = 0;
|
|
|
|
mod_delayed_work(system_wq, dwork, delay);
|
|
}
|
|
EXPORT_SYMBOL(snd_fw_schedule_registration);
|
|
|
|
MODULE_DESCRIPTION("FireWire audio helper functions");
|
|
MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
|
|
MODULE_LICENSE("GPL v2");
|