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![Thomas Gleixner](/assets/img/avatar_default.png)
ktime_set(S,N) was required for the timespec storage type and is still useful for situations where a Seconds and Nanoseconds part of a time value needs to be converted. For anything where the Seconds argument is 0, this is pointless and can be replaced with a simple assignment. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
245 lines
7 KiB
C
245 lines
7 KiB
C
/*
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* miscellaneous helper functions
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*
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* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
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* Licensed under the terms of the GNU General Public License, version 2.
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*/
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/firewire.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include "lib.h"
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#define ERROR_RETRY_DELAY_MS 20
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/**
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* snd_fw_transaction - send a request and wait for its completion
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* @unit: the driver's unit on the target device
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* @tcode: the transaction code
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* @offset: the address in the target's address space
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* @buffer: input/output data
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* @length: length of @buffer
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* @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the
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* request only in that generation; use %FW_QUIET to suppress error
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* messages
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*
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* Submits an asynchronous request to the target device, and waits for the
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* response. The node ID and the current generation are derived from @unit.
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* On a bus reset or an error, the transaction is retried a few times.
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* Returns zero on success, or a negative error code.
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*/
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int snd_fw_transaction(struct fw_unit *unit, int tcode,
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u64 offset, void *buffer, size_t length,
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unsigned int flags)
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{
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struct fw_device *device = fw_parent_device(unit);
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int generation, rcode, tries = 0;
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generation = flags & FW_GENERATION_MASK;
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for (;;) {
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if (!(flags & FW_FIXED_GENERATION)) {
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generation = device->generation;
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smp_rmb(); /* node_id vs. generation */
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}
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rcode = fw_run_transaction(device->card, tcode,
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device->node_id, generation,
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device->max_speed, offset,
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buffer, length);
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if (rcode == RCODE_COMPLETE)
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return 0;
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if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
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return -EAGAIN;
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if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
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if (!(flags & FW_QUIET))
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dev_err(&unit->device,
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"transaction failed: %s\n",
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fw_rcode_string(rcode));
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return -EIO;
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}
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msleep(ERROR_RETRY_DELAY_MS);
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}
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}
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EXPORT_SYMBOL(snd_fw_transaction);
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#define PROBE_DELAY_MS (2 * MSEC_PER_SEC)
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/**
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* snd_fw_schedule_registration - schedule work for sound card registration
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* @unit: an instance for unit on IEEE 1394 bus
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* @dwork: delayed work with callback function
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*
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* This function is not designed for general purposes. When new unit is
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* connected to IEEE 1394 bus, the bus is under bus-reset state because of
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* topological change. In this state, units tend to fail both of asynchronous
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* and isochronous communication. To avoid this problem, this function is used
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* to postpone sound card registration after the state. The callers must
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* set up instance of delayed work in advance.
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*/
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void snd_fw_schedule_registration(struct fw_unit *unit,
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struct delayed_work *dwork)
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{
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u64 now, delay;
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now = get_jiffies_64();
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delay = fw_parent_device(unit)->card->reset_jiffies
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+ msecs_to_jiffies(PROBE_DELAY_MS);
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if (time_after64(delay, now))
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delay -= now;
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else
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delay = 0;
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mod_delayed_work(system_wq, dwork, delay);
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}
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EXPORT_SYMBOL(snd_fw_schedule_registration);
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static void async_midi_port_callback(struct fw_card *card, int rcode,
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void *data, size_t length,
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void *callback_data)
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{
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struct snd_fw_async_midi_port *port = callback_data;
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struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
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/* This port is closed. */
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if (substream == NULL)
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return;
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if (rcode == RCODE_COMPLETE)
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snd_rawmidi_transmit_ack(substream, port->consume_bytes);
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else if (!rcode_is_permanent_error(rcode))
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/* To start next transaction immediately for recovery. */
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port->next_ktime = 0;
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else
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/* Don't continue processing. */
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port->error = true;
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port->idling = true;
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if (!snd_rawmidi_transmit_empty(substream))
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schedule_work(&port->work);
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}
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static void midi_port_work(struct work_struct *work)
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{
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struct snd_fw_async_midi_port *port =
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container_of(work, struct snd_fw_async_midi_port, work);
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struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
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int generation;
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int type;
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/* Under transacting or error state. */
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if (!port->idling || port->error)
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return;
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/* Nothing to do. */
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if (substream == NULL || snd_rawmidi_transmit_empty(substream))
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return;
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/* Do it in next chance. */
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if (ktime_after(port->next_ktime, ktime_get())) {
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schedule_work(&port->work);
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return;
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}
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/*
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* Fill the buffer. The callee must use snd_rawmidi_transmit_peek().
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* Later, snd_rawmidi_transmit_ack() is called.
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*/
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memset(port->buf, 0, port->len);
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port->consume_bytes = port->fill(substream, port->buf);
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if (port->consume_bytes <= 0) {
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/* Do it in next chance, immediately. */
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if (port->consume_bytes == 0) {
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port->next_ktime = 0;
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schedule_work(&port->work);
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} else {
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/* Fatal error. */
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port->error = true;
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}
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return;
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}
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/* Calculate type of transaction. */
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if (port->len == 4)
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type = TCODE_WRITE_QUADLET_REQUEST;
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else
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type = TCODE_WRITE_BLOCK_REQUEST;
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/* Set interval to next transaction. */
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port->next_ktime = ktime_add_ns(ktime_get(),
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port->consume_bytes * 8 * NSEC_PER_SEC / 31250);
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/* Start this transaction. */
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port->idling = false;
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/*
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* In Linux FireWire core, when generation is updated with memory
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* barrier, node id has already been updated. In this module, After
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* this smp_rmb(), load/store instructions to memory are completed.
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* Thus, both of generation and node id are available with recent
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* values. This is a light-serialization solution to handle bus reset
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* events on IEEE 1394 bus.
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*/
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generation = port->parent->generation;
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smp_rmb();
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fw_send_request(port->parent->card, &port->transaction, type,
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port->parent->node_id, generation,
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port->parent->max_speed, port->addr,
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port->buf, port->len, async_midi_port_callback,
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port);
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}
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/**
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* snd_fw_async_midi_port_init - initialize asynchronous MIDI port structure
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* @port: the asynchronous MIDI port to initialize
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* @unit: the target of the asynchronous transaction
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* @addr: the address to which transactions are transferred
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* @len: the length of transaction
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* @fill: the callback function to fill given buffer, and returns the
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* number of consumed bytes for MIDI message.
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*
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*/
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int snd_fw_async_midi_port_init(struct snd_fw_async_midi_port *port,
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struct fw_unit *unit, u64 addr, unsigned int len,
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snd_fw_async_midi_port_fill fill)
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{
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port->len = DIV_ROUND_UP(len, 4) * 4;
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port->buf = kzalloc(port->len, GFP_KERNEL);
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if (port->buf == NULL)
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return -ENOMEM;
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port->parent = fw_parent_device(unit);
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port->addr = addr;
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port->fill = fill;
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port->idling = true;
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port->next_ktime = 0;
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port->error = false;
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INIT_WORK(&port->work, midi_port_work);
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return 0;
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}
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EXPORT_SYMBOL(snd_fw_async_midi_port_init);
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/**
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* snd_fw_async_midi_port_destroy - free asynchronous MIDI port structure
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* @port: the asynchronous MIDI port structure
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*/
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void snd_fw_async_midi_port_destroy(struct snd_fw_async_midi_port *port)
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{
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snd_fw_async_midi_port_finish(port);
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cancel_work_sync(&port->work);
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kfree(port->buf);
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}
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EXPORT_SYMBOL(snd_fw_async_midi_port_destroy);
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MODULE_DESCRIPTION("FireWire audio helper functions");
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MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
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MODULE_LICENSE("GPL v2");
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