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/*
* miscellaneous helper functions
*
* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
* Licensed under the terms of the GNU General Public License, version 2.
*/
#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);
static void async_midi_port_callback(struct fw_card *card, int rcode,
void *data, size_t length,
void *callback_data)
{
struct snd_fw_async_midi_port *port = callback_data;
struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
if (rcode == RCODE_COMPLETE && substream != NULL)
snd_rawmidi_transmit_ack(substream, port->consume_bytes);
else if (!rcode_is_permanent_error(rcode))
/* To start next transaction immediately for recovery. */
port->next_ktime = ktime_set(0, 0);
port->idling = true;
if (!snd_rawmidi_transmit_empty(substream))
schedule_work(&port->work);
}
static void midi_port_work(struct work_struct *work)
{
struct snd_fw_async_midi_port *port =
container_of(work, struct snd_fw_async_midi_port, work);
struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
int generation;
int type;
/* Under transacting. */
if (!port->idling)
return;
/* Nothing to do. */
if (substream == NULL || snd_rawmidi_transmit_empty(substream))
return;
/* Do it in next chance. */
if (ktime_after(port->next_ktime, ktime_get())) {
schedule_work(&port->work);
return;
}
/*
* Fill the buffer. The callee must use snd_rawmidi_transmit_peek().
* Later, snd_rawmidi_transmit_ack() is called.
*/
memset(port->buf, 0, port->len);
port->consume_bytes = port->fill(substream, port->buf);
if (port->consume_bytes <= 0) {
/* Do it in next chance, immediately. */
if (port->consume_bytes == 0) {
port->next_ktime = ktime_set(0, 0);
schedule_work(&port->work);
}
return;
}
/* Calculate type of transaction. */
if (port->len == 4)
type = TCODE_WRITE_QUADLET_REQUEST;
else
type = TCODE_WRITE_BLOCK_REQUEST;
/* Set interval to next transaction. */
port->next_ktime = ktime_add_ns(ktime_get(),
port->consume_bytes * 8 * NSEC_PER_SEC / 31250);
/* Start this transaction. */
port->idling = false;
/*
* In Linux FireWire core, when generation is updated with memory
* barrier, node id has already been updated. In this module, After
* this smp_rmb(), load/store instructions to memory are completed.
* Thus, both of generation and node id are available with recent
* values. This is a light-serialization solution to handle bus reset
* events on IEEE 1394 bus.
*/
generation = port->parent->generation;
smp_rmb();
fw_send_request(port->parent->card, &port->transaction, type,
port->parent->node_id, generation,
port->parent->max_speed, port->addr,
port->buf, port->len, async_midi_port_callback,
port);
}
/**
* snd_fw_async_midi_port_init - initialize asynchronous MIDI port structure
* @port: the asynchronous MIDI port to initialize
* @unit: the target of the asynchronous transaction
* @addr: the address to which transactions are transferred
* @len: the length of transaction
* @fill: the callback function to fill given buffer, and returns the
* number of consumed bytes for MIDI message.
*
*/
int snd_fw_async_midi_port_init(struct snd_fw_async_midi_port *port,
struct fw_unit *unit, u64 addr, unsigned int len,
snd_fw_async_midi_port_fill fill)
{
port->len = DIV_ROUND_UP(len, 4) * 4;
port->buf = kzalloc(port->len, GFP_KERNEL);
if (port->buf == NULL)
return -ENOMEM;
port->parent = fw_parent_device(unit);
port->addr = addr;
port->fill = fill;
port->idling = true;
port->next_ktime = ktime_set(0, 0);
INIT_WORK(&port->work, midi_port_work);
return 0;
}
EXPORT_SYMBOL(snd_fw_async_midi_port_init);
/**
* snd_fw_async_midi_port_destroy - free asynchronous MIDI port structure
* @port: the asynchronous MIDI port structure
*/
void snd_fw_async_midi_port_destroy(struct snd_fw_async_midi_port *port)
{
snd_fw_async_midi_port_finish(port);
cancel_work_sync(&port->work);
kfree(port->buf);
}
EXPORT_SYMBOL(snd_fw_async_midi_port_destroy);
MODULE_DESCRIPTION("FireWire audio helper functions");
MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
MODULE_LICENSE("GPL v2");
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