/* * 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 "lib.h" #define ERROR_RETRY_DELAY_MS	5 /** * 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",				fw_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 <clemens@ladisch.de>");MODULE_LICENSE("GPL v2");