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sound/firewire/lib.c
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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 "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
",
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");
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