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

/*
 * miscellaneous helper functions
 *
 * Copyright (c) Clemens Ladisch <[email protected]>
 * 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 "lib.h"

#define ERROR_RETRY_DELAY_MS	5

/**
 * rcode_string - convert a firewire result code to a string
 * @rcode: the result
 */
const char *rcode_string(unsigned int rcode)
{
	static const char *const names[] = {
		[RCODE_COMPLETE]	= "complete",
		[RCODE_CONFLICT_ERROR]	= "conflict error",
		[RCODE_DATA_ERROR]	= "data error",
		[RCODE_TYPE_ERROR]	= "type error",
		[RCODE_ADDRESS_ERROR]	= "address error",
		[RCODE_SEND_ERROR]	= "send error",
		[RCODE_CANCELLED]	= "cancelled",
		[RCODE_BUSY]		= "busy",
		[RCODE_GENERATION]	= "generation",
		[RCODE_NO_ACK]		= "no ack",
	};

	if (rcode < ARRAY_SIZE(names) && names[rcode])
		return names[rcode];
	else
		return "unknown";
}
EXPORT_SYMBOL(rcode_string);

/**
 * 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
 *
 * 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)
{
	struct fw_device *device = fw_parent_device(unit);
	int generation, rcode, tries = 0;

	for (;;) {
		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_is_permanent_error(rcode) || ++tries >= 3) {
			dev_err(&unit->device, "transaction failed: %s\n",
				rcode_string(rcode));
			return -EIO;
		}

		msleep(ERROR_RETRY_DELAY_MS);
	}
}
EXPORT_SYMBOL(snd_fw_transaction);

MODULE_DESCRIPTION("FireWire audio helper functions");
MODULE_AUTHOR("Clemens Ladisch <[email protected]>");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
31ef9134 CL	1	/*
	2	* miscellaneous helper functions
	3	*
	4	* Copyright (c) Clemens Ladisch <[email protected]>
	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>
	12	#include "lib.h"
	13
	14	#define ERROR_RETRY_DELAY_MS 5
	15
	16	/**
	17	* rcode_string - convert a firewire result code to a string
	18	* @rcode: the result
	19	*/
	20	const char *rcode_string(unsigned int rcode)
	21	{
	22	static const char *const names[] = {
	23	[RCODE_COMPLETE] = "complete",
	24	[RCODE_CONFLICT_ERROR] = "conflict error",
	25	[RCODE_DATA_ERROR] = "data error",
	26	[RCODE_TYPE_ERROR] = "type error",
	27	[RCODE_ADDRESS_ERROR] = "address error",
	28	[RCODE_SEND_ERROR] = "send error",
	29	[RCODE_CANCELLED] = "cancelled",
	30	[RCODE_BUSY] = "busy",
	31	[RCODE_GENERATION] = "generation",
	32	[RCODE_NO_ACK] = "no ack",
	33	};
	34
	35	if (rcode < ARRAY_SIZE(names) && names[rcode])
	36	return names[rcode];
	37	else
	38	return "unknown";
	39	}
	40	EXPORT_SYMBOL(rcode_string);
	41
	42	/**
	43	* snd_fw_transaction - send a request and wait for its completion
	44	* @unit: the driver's unit on the target device
	45	* @tcode: the transaction code
	46	* @offset: the address in the target's address space
	47	* @buffer: input/output data
	48	* @length: length of @buffer
	49	*
	50	* Submits an asynchronous request to the target device, and waits for the
	51	* response. The node ID and the current generation are derived from @unit.
	52	* On a bus reset or an error, the transaction is retried a few times.
	53	* Returns zero on success, or a negative error code.
	54	*/
	55	int snd_fw_transaction(struct fw_unit *unit, int tcode,
	56	u64 offset, void *buffer, size_t length)
	57	{
	58	struct fw_device *device = fw_parent_device(unit);
	59	int generation, rcode, tries = 0;
	60
	61	for (;;) {
	62	generation = device->generation;
	63	smp_rmb(); /* node_id vs. generation */
	64	rcode = fw_run_transaction(device->card, tcode,
65	device->node_id, generation,
66	device->max_speed, offset,
67	buffer, length);
68
69	if (rcode == RCODE_COMPLETE)
70	return 0;
71
72	if (rcode_is_permanent_error(rcode) \|\| ++tries >= 3) {
73	dev_err(&unit->device, "transaction failed: %s\n",
74	rcode_string(rcode));
75	return -EIO;
76	}
77
78	msleep(ERROR_RETRY_DELAY_MS);
79	}
80	}
81	EXPORT_SYMBOL(snd_fw_transaction);
82
83	MODULE_DESCRIPTION("FireWire audio helper functions");
84	MODULE_AUTHOR("Clemens Ladisch <[email protected]>");
85	MODULE_LICENSE("GPL v2");