sound/firewire/lib.c - kernel/quantenna - Git at Google

 /*
  * 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);

 #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);

 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");
	/*
	* 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);

	#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);

	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");