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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);
- /* This port is closed. */
- if (substream == NULL)
- return;
- if (rcode == RCODE_COMPLETE)
- 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);
- else
- /* Don't continue processing. */
- port->error = true;
- 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 or error state. */
- if (!port->idling || port->error)
- 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);
- } else {
- /* Fatal error. */
- port->error = true;
- }
- 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);
- port->error = false;
- 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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