[deliverable/linux.git] / sound / firewire / lib.c

/*
 * 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);
	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");
Commit	Line	Data
31ef9134 CL	1	/*
	2	* miscellaneous helper functions
	3	*
	4	* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
	5	* Licensed under the terms of the GNU General Public License, version 2.
	6	*/
	7
	8	#include <linux/delay.h>
	9	#include <linux/device.h>
	10	#include <linux/firewire.h>
	11	#include <linux/module.h>
585d7cba	12	#include <linux/slab.h>
31ef9134 CL	13	#include "lib.h"
31ef9134 CL	14
1b70485f	15	#define ERROR_RETRY_DELAY_MS 20
31ef9134	16
31ef9134 CL	17	/**
	18	* snd_fw_transaction - send a request and wait for its completion
	19	* @unit: the driver's unit on the target device
	20	* @tcode: the transaction code
	21	* @offset: the address in the target's address space
	22	* @buffer: input/output data
	23	* @length: length of @buffer
1b70485f CL	24	* @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the
	25	* request only in that generation; use %FW_QUIET to suppress error
	26	* messages
31ef9134 CL	27	*
	28	* Submits an asynchronous request to the target device, and waits for the
	29	* response. The node ID and the current generation are derived from @unit.
	30	* On a bus reset or an error, the transaction is retried a few times.
	31	* Returns zero on success, or a negative error code.
	32	*/
	33	int snd_fw_transaction(struct fw_unit *unit, int tcode,
1b70485f CL	34	u64 offset, void *buffer, size_t length,
1b70485f CL	35	unsigned int flags)
31ef9134 CL	36	{
	37	struct fw_device *device = fw_parent_device(unit);
	38	int generation, rcode, tries = 0;
	39
1b70485f	40	generation = flags & FW_GENERATION_MASK;
31ef9134	41	for (;;) {
1b70485f CL	42	if (!(flags & FW_FIXED_GENERATION)) {
	43	generation = device->generation;
	44	smp_rmb(); /* node_id vs. generation */
	45	}
31ef9134 CL	46	rcode = fw_run_transaction(device->card, tcode,
	47	device->node_id, generation,
	48	device->max_speed, offset,
	49	buffer, length);
	50
	51	if (rcode == RCODE_COMPLETE)
	52	return 0;
	53
1b70485f CL	54	if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
	55	return -EAGAIN;
	56
31ef9134	57	if (rcode_is_permanent_error(rcode) \|\| ++tries >= 3) {
1b70485f CL	58	if (!(flags & FW_QUIET))
	59	dev_err(&unit->device,
	60	"transaction failed: %s\n",
	61	fw_rcode_string(rcode));
31ef9134 CL	62	return -EIO;
	63	}
	64
	65	msleep(ERROR_RETRY_DELAY_MS);
	66	}
	67	}
	68	EXPORT_SYMBOL(snd_fw_transaction);
	69
585d7cba TS	70	static void async_midi_port_callback(struct fw_card *card, int rcode,
	71	void *data, size_t length,
	72	void *callback_data)
	73	{
	74	struct snd_fw_async_midi_port *port = callback_data;
	75	struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
	76
	77	if (rcode == RCODE_COMPLETE && substream != NULL)
	78	snd_rawmidi_transmit_ack(substream, port->consume_bytes);
ea848b7b TS	79	else if (!rcode_is_permanent_error(rcode))
	80	/* To start next transaction immediately for recovery. */
	81	port->next_ktime = ktime_set(0, 0);
bde3e288 TS	82	else
	83	/* Don't continue processing. */
	84	port->error = true;
d3ef9cb9 TS	85
d3ef9cb9 TS	86	port->idling = true;
e8a40d9b TS	87
	88	if (!snd_rawmidi_transmit_empty(substream))
	89	schedule_work(&port->work);
585d7cba TS	90	}
	91
	92	static void midi_port_work(struct work_struct *work)
	93	{
	94	struct snd_fw_async_midi_port *port =
	95	container_of(work, struct snd_fw_async_midi_port, work);
	96	struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
	97	int generation;
	98	int type;
	99
bde3e288 TS	100	/* Under transacting or error state. */
bde3e288 TS	101	if (!port->idling \|\| port->error)
d3ef9cb9 TS	102	return;
d3ef9cb9 TS	103
585d7cba TS	104	/* Nothing to do. */
	105	if (substream == NULL \|\| snd_rawmidi_transmit_empty(substream))
	106	return;
	107
ea848b7b TS	108	/* Do it in next chance. */
	109	if (ktime_after(port->next_ktime, ktime_get())) {
	110	schedule_work(&port->work);
	111	return;
	112	}
	113
585d7cba TS	114	/*
	115	* Fill the buffer. The callee must use snd_rawmidi_transmit_peek().
	116	* Later, snd_rawmidi_transmit_ack() is called.
	117	*/
	118	memset(port->buf, 0, port->len);
	119	port->consume_bytes = port->fill(substream, port->buf);
	120	if (port->consume_bytes <= 0) {
	121	/* Do it in next chance, immediately. */
ea848b7b TS	122	if (port->consume_bytes == 0) {
ea848b7b TS	123	port->next_ktime = ktime_set(0, 0);
585d7cba	124	schedule_work(&port->work);
bde3e288 TS	125	} else {
	126	/* Fatal error. */
	127	port->error = true;
ea848b7b	128	}
585d7cba TS	129	return;
	130	}
	131
	132	/* Calculate type of transaction. */
	133	if (port->len == 4)
	134	type = TCODE_WRITE_QUADLET_REQUEST;
	135	else
	136	type = TCODE_WRITE_BLOCK_REQUEST;
	137
ea848b7b TS	138	/* Set interval to next transaction. */
	139	port->next_ktime = ktime_add_ns(ktime_get(),
	140	port->consume_bytes * 8 * NSEC_PER_SEC / 31250);
	141
585d7cba	142	/* Start this transaction. */
d3ef9cb9 TS	143	port->idling = false;
d3ef9cb9 TS	144
585d7cba TS	145	/*
	146	* In Linux FireWire core, when generation is updated with memory
	147	* barrier, node id has already been updated. In this module, After
	148	* this smp_rmb(), load/store instructions to memory are completed.
	149	* Thus, both of generation and node id are available with recent
	150	* values. This is a light-serialization solution to handle bus reset
	151	* events on IEEE 1394 bus.
	152	*/
	153	generation = port->parent->generation;
	154	smp_rmb();
	155
	156	fw_send_request(port->parent->card, &port->transaction, type,
	157	port->parent->node_id, generation,
	158	port->parent->max_speed, port->addr,
	159	port->buf, port->len, async_midi_port_callback,
	160	port);
	161	}
	162
	163	/**
	164	* snd_fw_async_midi_port_init - initialize asynchronous MIDI port structure
	165	* @port: the asynchronous MIDI port to initialize
	166	* @unit: the target of the asynchronous transaction
	167	* @addr: the address to which transactions are transferred
	168	* @len: the length of transaction
	169	* @fill: the callback function to fill given buffer, and returns the
	170	* number of consumed bytes for MIDI message.
	171	*
	172	*/
	173	int snd_fw_async_midi_port_init(struct snd_fw_async_midi_port *port,
	174	struct fw_unit *unit, u64 addr, unsigned int len,
	175	snd_fw_async_midi_port_fill fill)
	176	{
	177	port->len = DIV_ROUND_UP(len, 4) * 4;
	178	port->buf = kzalloc(port->len, GFP_KERNEL);
	179	if (port->buf == NULL)
	180	return -ENOMEM;
	181
	182	port->parent = fw_parent_device(unit);
	183	port->addr = addr;
	184	port->fill = fill;
d3ef9cb9	185	port->idling = true;
ea848b7b	186	port->next_ktime = ktime_set(0, 0);
bde3e288	187	port->error = false;
585d7cba TS	188
	189	INIT_WORK(&port->work, midi_port_work);
	190
	191	return 0;
	192	}
	193	EXPORT_SYMBOL(snd_fw_async_midi_port_init);
	194
	195	/**
	196	* snd_fw_async_midi_port_destroy - free asynchronous MIDI port structure
	197	* @port: the asynchronous MIDI port structure
	198	*/
	199	void snd_fw_async_midi_port_destroy(struct snd_fw_async_midi_port *port)
	200	{
	201	snd_fw_async_midi_port_finish(port);
	202	cancel_work_sync(&port->work);
	203	kfree(port->buf);
	204	}
	205	EXPORT_SYMBOL(snd_fw_async_midi_port_destroy);
	206
31ef9134 CL	207	MODULE_DESCRIPTION("FireWire audio helper functions");
	208	MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
	209	MODULE_LICENSE("GPL v2");