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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273// SPDX-License-Identifier: GPL-2.0-only/* * miscellaneous helper functions * * Copyright (c) Clemens Ladisch <clemens@ladisch.de> */
#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);
MODULE_DESCRIPTION("FireWire audio helper functions");MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");MODULE_LICENSE("GPL");